file.c

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/*
 * SPU file system -- file contents
 *
 * (C) Copyright IBM Deutschland Entwicklung GmbH 2005
 *
 * Author: Arnd Bergmann <[email protected]>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2, or (at your option)
 * any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 */

#undef DEBUG

#include <linux/fs.h>
#include <linux/ioctl.h>
#include <linux/export.h>
#include <linux/pagemap.h>
#include <linux/poll.h>
#include <linux/ptrace.h>
#include <linux/seq_file.h>
#include <linux/slab.h>

#include <asm/io.h>
#include <asm/time.h>
#include <asm/spu.h>
#include <asm/spu_info.h>
#include <asm/uaccess.h>

#include "spufs.h"
#include "sputrace.h"

#define SPUFS_MMAP_4K (PAGE_SIZE == 0x1000)

/* Simple attribute files */
struct spufs_attr {
    int (*get)(void *, u64 *);
    int (*set)(void *, u64);
    char get_buf[24];       /* enough to store a u64 and "\n\0" */
    char set_buf[24];
    void *data;
    const char *fmt;        /* format for read operation */
    struct mutex mutex;     /* protects access to these buffers */
};

static int spufs_attr_open(struct inode *inode, struct file *file,
        int (*get)(void *, u64 *), int (*set)(void *, u64),
        const char *fmt)
{
    struct spufs_attr *attr;

    attr = kmalloc(sizeof(*attr), GFP_KERNEL);
    if (!attr)
        return -ENOMEM;

    attr->get = get;
    attr->set = set;
    attr->data = inode->i_private;
    attr->fmt = fmt;
    mutex_init(&attr->mutex);
    file->private_data = attr;

    return nonseekable_open(inode, file);
}

static int spufs_attr_release(struct inode *inode, struct file *file)
{
       kfree(file->private_data);
    return 0;
}

static ssize_t spufs_attr_read(struct file *file, char __user *buf,
        size_t len, loff_t *ppos)
{
    struct spufs_attr *attr;
    size_t size;
    ssize_t ret;

    attr = file->private_data;
    if (!attr->get)
        return -EACCES;

    ret = mutex_lock_interruptible(&attr->mutex);
    if (ret)
        return ret;

    if (*ppos) {        /* continued read */
        size = strlen(attr->get_buf);
    } else {        /* first read */
        u64 val;
        ret = attr->get(attr->data, &val);
        if (ret)
            goto out;

        size = scnprintf(attr->get_buf, sizeof(attr->get_buf),
                 attr->fmt, (unsigned long long)val);
    }

    ret = simple_read_from_buffer(buf, len, ppos, attr->get_buf, size);
out:
    mutex_unlock(&attr->mutex);
    return ret;
}

static ssize_t spufs_attr_write(struct file *file, const char __user *buf,
        size_t len, loff_t *ppos)
{
    struct spufs_attr *attr;
    u64 val;
    size_t size;
    ssize_t ret;

    attr = file->private_data;
    if (!attr->set)
        return -EACCES;

    ret = mutex_lock_interruptible(&attr->mutex);
    if (ret)
        return ret;

    ret = -EFAULT;
    size = min(sizeof(attr->set_buf) - 1, len);
    if (copy_from_user(attr->set_buf, buf, size))
        goto out;

    ret = len; /* claim we got the whole input */
    attr->set_buf[size] = '\0';
    val = simple_strtol(attr->set_buf, NULL, 0);
    attr->set(attr->data, val);
out:
    mutex_unlock(&attr->mutex);
    return ret;
}

#define DEFINE_SPUFS_SIMPLE_ATTRIBUTE(__fops, __get, __set, __fmt)  \
static int __fops ## _open(struct inode *inode, struct file *file)  \
{                                   \
    __simple_attr_check_format(__fmt, 0ull);            \
    return spufs_attr_open(inode, file, __get, __set, __fmt);   \
}                                   \
static const struct file_operations __fops = {              \
    .owner   = THIS_MODULE,                     \
    .open    = __fops ## _open,                 \
    .release = spufs_attr_release,                  \
    .read    = spufs_attr_read,                 \
    .write   = spufs_attr_write,                    \
    .llseek  = generic_file_llseek,                 \
};


static int
spufs_mem_open(struct inode *inode, struct file *file)
{
    struct spufs_inode_info *i = SPUFS_I(inode);
    struct spu_context *ctx = i->i_ctx;

    mutex_lock(&ctx->mapping_lock);
    file->private_data = ctx;
    if (!i->i_openers++)
        ctx->local_store = inode->i_mapping;
    mutex_unlock(&ctx->mapping_lock);
    return 0;
}

static int
spufs_mem_release(struct inode *inode, struct file *file)
{
    struct spufs_inode_info *i = SPUFS_I(inode);
    struct spu_context *ctx = i->i_ctx;

    mutex_lock(&ctx->mapping_lock);
    if (!--i->i_openers)
        ctx->local_store = NULL;
    mutex_unlock(&ctx->mapping_lock);
    return 0;
}

static ssize_t
__spufs_mem_read(struct spu_context *ctx, char __user *buffer,
            size_t size, loff_t *pos)
{
    char *local_store = ctx->ops->get_ls(ctx);
    return simple_read_from_buffer(buffer, size, pos, local_store,
                    LS_SIZE);
}

static ssize_t
spufs_mem_read(struct file *file, char __user *buffer,
                size_t size, loff_t *pos)
{
    struct spu_context *ctx = file->private_data;
    ssize_t ret;

    ret = spu_acquire(ctx);
    if (ret)
        return ret;
    ret = __spufs_mem_read(ctx, buffer, size, pos);
    spu_release(ctx);

    return ret;
}

static ssize_t
spufs_mem_write(struct file *file, const char __user *buffer,
                    size_t size, loff_t *ppos)
{
    struct spu_context *ctx = file->private_data;
    char *local_store;
    loff_t pos = *ppos;
    int ret;

    if (pos > LS_SIZE)
        return -EFBIG;

    ret = spu_acquire(ctx);
    if (ret)
        return ret;

    local_store = ctx->ops->get_ls(ctx);
    size = simple_write_to_buffer(local_store, LS_SIZE, ppos, buffer, size);
    spu_release(ctx);

    return size;
}

static int
spufs_mem_mmap_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
{
    struct spu_context *ctx = vma->vm_file->private_data;
    unsigned long address = (unsigned long)vmf->virtual_address;
    unsigned long pfn, offset;

#ifdef CONFIG_SPU_FS_64K_LS
    struct spu_state *csa = &ctx->csa;
    int psize;

    /* Check what page size we are using */
    psize = get_slice_psize(vma->vm_mm, address);

    /* Some sanity checking */
    BUG_ON(csa->use_big_pages != (psize == MMU_PAGE_64K));

    /* Wow, 64K, cool, we need to align the address though */
    if (csa->use_big_pages) {
        BUG_ON(vma->vm_start & 0xffff);
        address &= ~0xfffful;
    }
#endif /* CONFIG_SPU_FS_64K_LS */

    offset = vmf->pgoff << PAGE_SHIFT;
    if (offset >= LS_SIZE)
        return VM_FAULT_SIGBUS;

    pr_debug("spufs_mem_mmap_fault address=0x%lx, offset=0x%lx\n",
            address, offset);

    if (spu_acquire(ctx))
        return VM_FAULT_NOPAGE;

    if (ctx->state == SPU_STATE_SAVED) {
        vma->vm_page_prot = pgprot_cached(vma->vm_page_prot);
        pfn = vmalloc_to_pfn(ctx->csa.lscsa->ls + offset);
    } else {
        vma->vm_page_prot = pgprot_noncached_wc(vma->vm_page_prot);
        pfn = (ctx->spu->local_store_phys + offset) >> PAGE_SHIFT;
    }
    vm_insert_pfn(vma, address, pfn);

    spu_release(ctx);

    return VM_FAULT_NOPAGE;
}

static int spufs_mem_mmap_access(struct vm_area_struct *vma,
                unsigned long address,
                void *buf, int len, int write)
{
    struct spu_context *ctx = vma->vm_file->private_data;
    unsigned long offset = address - vma->vm_start;
    char *local_store;

    if (write && !(vma->vm_flags & VM_WRITE))
        return -EACCES;
    if (spu_acquire(ctx))
        return -EINTR;
    if ((offset + len) > vma->vm_end)
        len = vma->vm_end - offset;
    local_store = ctx->ops->get_ls(ctx);
    if (write)
        memcpy_toio(local_store + offset, buf, len);
    else
        memcpy_fromio(buf, local_store + offset, len);
    spu_release(ctx);
    return len;
}

static const struct vm_operations_struct spufs_mem_mmap_vmops = {
    .fault = spufs_mem_mmap_fault,
    .access = spufs_mem_mmap_access,
};

static int spufs_mem_mmap(struct file *file, struct vm_area_struct *vma)
{
#ifdef CONFIG_SPU_FS_64K_LS
    struct spu_context  *ctx = file->private_data;
    struct spu_state    *csa = &ctx->csa;

    /* Sanity check VMA alignment */
    if (csa->use_big_pages) {
        pr_debug("spufs_mem_mmap 64K, start=0x%lx, end=0x%lx,"
             " pgoff=0x%lx\n", vma->vm_start, vma->vm_end,
             vma->vm_pgoff);
        if (vma->vm_start & 0xffff)
            return -EINVAL;
        if (vma->vm_pgoff & 0xf)
            return -EINVAL;
    }
#endif /* CONFIG_SPU_FS_64K_LS */

    if (!(vma->vm_flags & VM_SHARED))
        return -EINVAL;

    vma->vm_flags |= VM_IO | VM_PFNMAP;
    vma->vm_page_prot = pgprot_noncached_wc(vma->vm_page_prot);

    vma->vm_ops = &spufs_mem_mmap_vmops;
    return 0;
}

#ifdef CONFIG_SPU_FS_64K_LS
static unsigned long spufs_get_unmapped_area(struct file *file,
        unsigned long addr, unsigned long len, unsigned long pgoff,
        unsigned long flags)
{
    struct spu_context  *ctx = file->private_data;
    struct spu_state    *csa = &ctx->csa;

    /* If not using big pages, fallback to normal MM g_u_a */
    if (!csa->use_big_pages)
        return current->mm->get_unmapped_area(file, addr, len,
                              pgoff, flags);

    /* Else, try to obtain a 64K pages slice */
    return slice_get_unmapped_area(addr, len, flags,
                       MMU_PAGE_64K, 1, 0);
}
#endif /* CONFIG_SPU_FS_64K_LS */

static const struct file_operations spufs_mem_fops = {
    .open           = spufs_mem_open,
    .release        = spufs_mem_release,
    .read           = spufs_mem_read,
    .write          = spufs_mem_write,
    .llseek         = generic_file_llseek,
    .mmap           = spufs_mem_mmap,
#ifdef CONFIG_SPU_FS_64K_LS
    .get_unmapped_area  = spufs_get_unmapped_area,
#endif
};

static int spufs_ps_fault(struct vm_area_struct *vma,
                    struct vm_fault *vmf,
                    unsigned long ps_offs,
                    unsigned long ps_size)
{
    struct spu_context *ctx = vma->vm_file->private_data;
    unsigned long area, offset = vmf->pgoff << PAGE_SHIFT;
    int ret = 0;

    spu_context_nospu_trace(spufs_ps_fault__enter, ctx);

    if (offset >= ps_size)
        return VM_FAULT_SIGBUS;

    if (fatal_signal_pending(current))
        return VM_FAULT_SIGBUS;

    /*
     * Because we release the mmap_sem, the context may be destroyed while
     * we're in spu_wait. Grab an extra reference so it isn't destroyed
     * in the meantime.
     */
    get_spu_context(ctx);

    /*
     * We have to wait for context to be loaded before we have
     * pages to hand out to the user, but we don't want to wait
     * with the mmap_sem held.
     * It is possible to drop the mmap_sem here, but then we need
     * to return VM_FAULT_NOPAGE because the mappings may have
     * hanged.
     */
    if (spu_acquire(ctx))
        goto refault;

    if (ctx->state == SPU_STATE_SAVED) {
        up_read(&current->mm->mmap_sem);
        spu_context_nospu_trace(spufs_ps_fault__sleep, ctx);
        ret = spufs_wait(ctx->run_wq, ctx->state == SPU_STATE_RUNNABLE);
        spu_context_trace(spufs_ps_fault__wake, ctx, ctx->spu);
        down_read(&current->mm->mmap_sem);
    } else {
        area = ctx->spu->problem_phys + ps_offs;
        vm_insert_pfn(vma, (unsigned long)vmf->virtual_address,
                    (area + offset) >> PAGE_SHIFT);
        spu_context_trace(spufs_ps_fault__insert, ctx, ctx->spu);
    }

    if (!ret)
        spu_release(ctx);

refault:
    put_spu_context(ctx);
    return VM_FAULT_NOPAGE;
}

#if SPUFS_MMAP_4K
static int spufs_cntl_mmap_fault(struct vm_area_struct *vma,
                       struct vm_fault *vmf)
{
    return spufs_ps_fault(vma, vmf, 0x4000, SPUFS_CNTL_MAP_SIZE);
}

static const struct vm_operations_struct spufs_cntl_mmap_vmops = {
    .fault = spufs_cntl_mmap_fault,
};

/*
 * mmap support for problem state control area [0x4000 - 0x4fff].
 */
static int spufs_cntl_mmap(struct file *file, struct vm_area_struct *vma)
{
    if (!(vma->vm_flags & VM_SHARED))
        return -EINVAL;

    vma->vm_flags |= VM_IO | VM_PFNMAP;
    vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);

    vma->vm_ops = &spufs_cntl_mmap_vmops;
    return 0;
}
#else /* SPUFS_MMAP_4K */
#define spufs_cntl_mmap NULL
#endif /* !SPUFS_MMAP_4K */

static int spufs_cntl_get(void *data, u64 *val)
{
    struct spu_context *ctx = data;
    int ret;

    ret = spu_acquire(ctx);
    if (ret)
        return ret;
    *val = ctx->ops->status_read(ctx);
    spu_release(ctx);

    return 0;
}

static int spufs_cntl_set(void *data, u64 val)
{
    struct spu_context *ctx = data;
    int ret;

    ret = spu_acquire(ctx);
    if (ret)
        return ret;
    ctx->ops->runcntl_write(ctx, val);
    spu_release(ctx);

    return 0;
}

static int spufs_cntl_open(struct inode *inode, struct file *file)
{
    struct spufs_inode_info *i = SPUFS_I(inode);
    struct spu_context *ctx = i->i_ctx;

    mutex_lock(&ctx->mapping_lock);
    file->private_data = ctx;
    if (!i->i_openers++)
        ctx->cntl = inode->i_mapping;
    mutex_unlock(&ctx->mapping_lock);
    return simple_attr_open(inode, file, spufs_cntl_get,
                    spufs_cntl_set, "0x%08lx");
}

static int
spufs_cntl_release(struct inode *inode, struct file *file)
{
    struct spufs_inode_info *i = SPUFS_I(inode);
    struct spu_context *ctx = i->i_ctx;

    simple_attr_release(inode, file);

    mutex_lock(&ctx->mapping_lock);
    if (!--i->i_openers)
        ctx->cntl = NULL;
    mutex_unlock(&ctx->mapping_lock);
    return 0;
}

static const struct file_operations spufs_cntl_fops = {
    .open = spufs_cntl_open,
    .release = spufs_cntl_release,
    .read = simple_attr_read,
    .write = simple_attr_write,
    .llseek = generic_file_llseek,
    .mmap = spufs_cntl_mmap,
};

static int
spufs_regs_open(struct inode *inode, struct file *file)
{
    struct spufs_inode_info *i = SPUFS_I(inode);
    file->private_data = i->i_ctx;
    return 0;
}

static ssize_t
__spufs_regs_read(struct spu_context *ctx, char __user *buffer,
            size_t size, loff_t *pos)
{
    struct spu_lscsa *lscsa = ctx->csa.lscsa;
    return simple_read_from_buffer(buffer, size, pos,
                      lscsa->gprs, sizeof lscsa->gprs);
}

static ssize_t
spufs_regs_read(struct file *file, char __user *buffer,
        size_t size, loff_t *pos)
{
    int ret;
    struct spu_context *ctx = file->private_data;

    /* pre-check for file position: if we'd return EOF, there's no point
     * causing a deschedule */
    if (*pos >= sizeof(ctx->csa.lscsa->gprs))
        return 0;

    ret = spu_acquire_saved(ctx);
    if (ret)
        return ret;
    ret = __spufs_regs_read(ctx, buffer, size, pos);
    spu_release_saved(ctx);
    return ret;
}

static ssize_t
spufs_regs_write(struct file *file, const char __user *buffer,
         size_t size, loff_t *pos)
{
    struct spu_context *ctx = file->private_data;
    struct spu_lscsa *lscsa = ctx->csa.lscsa;
    int ret;

    if (*pos >= sizeof(lscsa->gprs))
        return -EFBIG;

    ret = spu_acquire_saved(ctx);
    if (ret)
        return ret;

    size = simple_write_to_buffer(lscsa->gprs, sizeof(lscsa->gprs), pos,
                    buffer, size);

    spu_release_saved(ctx);
    return size;
}

static const struct file_operations spufs_regs_fops = {
    .open    = spufs_regs_open,
    .read    = spufs_regs_read,
    .write   = spufs_regs_write,
    .llseek  = generic_file_llseek,
};

static ssize_t
__spufs_fpcr_read(struct spu_context *ctx, char __user * buffer,
            size_t size, loff_t * pos)
{
    struct spu_lscsa *lscsa = ctx->csa.lscsa;
    return simple_read_from_buffer(buffer, size, pos,
                      &lscsa->fpcr, sizeof(lscsa->fpcr));
}

static ssize_t
spufs_fpcr_read(struct file *file, char __user * buffer,
        size_t size, loff_t * pos)
{
    int ret;
    struct spu_context *ctx = file->private_data;

    ret = spu_acquire_saved(ctx);
    if (ret)
        return ret;
    ret = __spufs_fpcr_read(ctx, buffer, size, pos);
    spu_release_saved(ctx);
    return ret;
}

static ssize_t
spufs_fpcr_write(struct file *file, const char __user * buffer,
         size_t size, loff_t * pos)
{
    struct spu_context *ctx = file->private_data;
    struct spu_lscsa *lscsa = ctx->csa.lscsa;
    int ret;

    if (*pos >= sizeof(lscsa->fpcr))
        return -EFBIG;

    ret = spu_acquire_saved(ctx);
    if (ret)
        return ret;

    size = simple_write_to_buffer(&lscsa->fpcr, sizeof(lscsa->fpcr), pos,
                    buffer, size);

    spu_release_saved(ctx);
    return size;
}

static const struct file_operations spufs_fpcr_fops = {
    .open = spufs_regs_open,
    .read = spufs_fpcr_read,
    .write = spufs_fpcr_write,
    .llseek = generic_file_llseek,
};

/* generic open function for all pipe-like files */
static int spufs_pipe_open(struct inode *inode, struct file *file)
{
    struct spufs_inode_info *i = SPUFS_I(inode);
    file->private_data = i->i_ctx;

    return nonseekable_open(inode, file);
}

/*
 * Read as many bytes from the mailbox as possible, until
 * one of the conditions becomes true:
 *
 * - no more data available in the mailbox
 * - end of the user provided buffer
 * - end of the mapped area
 */
static ssize_t spufs_mbox_read(struct file *file, char __user *buf,
            size_t len, loff_t *pos)
{
    struct spu_context *ctx = file->private_data;
    u32 mbox_data, __user *udata;
    ssize_t count;

    if (len < 4)
        return -EINVAL;

    if (!access_ok(VERIFY_WRITE, buf, len))
        return -EFAULT;

    udata = (void __user *)buf;

    count = spu_acquire(ctx);
    if (count)
        return count;

    for (count = 0; (count + 4) <= len; count += 4, udata++) {
        int ret;
        ret = ctx->ops->mbox_read(ctx, &mbox_data);
        if (ret == 0)
            break;

        /*
         * at the end of the mapped area, we can fault
         * but still need to return the data we have
         * read successfully so far.
         */
        ret = __put_user(mbox_data, udata);
        if (ret) {
            if (!count)
                count = -EFAULT;
            break;
        }
    }
    spu_release(ctx);

    if (!count)
        count = -EAGAIN;

    return count;
}

static const struct file_operations spufs_mbox_fops = {
    .open   = spufs_pipe_open,
    .read   = spufs_mbox_read,
    .llseek = no_llseek,
};

static ssize_t spufs_mbox_stat_read(struct file *file, char __user *buf,
            size_t len, loff_t *pos)
{
    struct spu_context *ctx = file->private_data;
    ssize_t ret;
    u32 mbox_stat;

    if (len < 4)
        return -EINVAL;

    ret = spu_acquire(ctx);
    if (ret)
        return ret;

    mbox_stat = ctx->ops->mbox_stat_read(ctx) & 0xff;

    spu_release(ctx);

    if (copy_to_user(buf, &mbox_stat, sizeof mbox_stat))
        return -EFAULT;

    return 4;
}

static const struct file_operations spufs_mbox_stat_fops = {
    .open   = spufs_pipe_open,
    .read   = spufs_mbox_stat_read,
    .llseek = no_llseek,
};

/* low-level ibox access function */
size_t spu_ibox_read(struct spu_context *ctx, u32 *data)
{
    return ctx->ops->ibox_read(ctx, data);
}

static int spufs_ibox_fasync(int fd, struct file *file, int on)
{
    struct spu_context *ctx = file->private_data;

    return fasync_helper(fd, file, on, &ctx->ibox_fasync);
}

/* interrupt-level ibox callback function. */
void spufs_ibox_callback(struct spu *spu)
{
    struct spu_context *ctx = spu->ctx;

    if (!ctx)
        return;

    wake_up_all(&ctx->ibox_wq);
    kill_fasync(&ctx->ibox_fasync, SIGIO, POLLIN);
}

/*
 * Read as many bytes from the interrupt mailbox as possible, until
 * one of the conditions becomes true:
 *
 * - no more data available in the mailbox
 * - end of the user provided buffer
 * - end of the mapped area
 *
 * If the file is opened without O_NONBLOCK, we wait here until
 * any data is available, but return when we have been able to
 * read something.
 */
static ssize_t spufs_ibox_read(struct file *file, char __user *buf,
            size_t len, loff_t *pos)
{
    struct spu_context *ctx = file->private_data;
    u32 ibox_data, __user *udata;
    ssize_t count;

    if (len < 4)
        return -EINVAL;

    if (!access_ok(VERIFY_WRITE, buf, len))
        return -EFAULT;

    udata = (void __user *)buf;

    count = spu_acquire(ctx);
    if (count)
        goto out;

    /* wait only for the first element */
    count = 0;
    if (file->f_flags & O_NONBLOCK) {
        if (!spu_ibox_read(ctx, &ibox_data)) {
            count = -EAGAIN;
            goto out_unlock;
        }
    } else {
        count = spufs_wait(ctx->ibox_wq, spu_ibox_read(ctx, &ibox_data));
        if (count)
            goto out;
    }

    /* if we can't write at all, return -EFAULT */
    count = __put_user(ibox_data, udata);
    if (count)
        goto out_unlock;

    for (count = 4, udata++; (count + 4) <= len; count += 4, udata++) {
        int ret;
        ret = ctx->ops->ibox_read(ctx, &ibox_data);
        if (ret == 0)
            break;
        /*
         * at the end of the mapped area, we can fault
         * but still need to return the data we have
         * read successfully so far.
         */
        ret = __put_user(ibox_data, udata);
        if (ret)
            break;
    }

out_unlock:
    spu_release(ctx);
out:
    return count;
}

static unsigned int spufs_ibox_poll(struct file *file, poll_table *wait)
{
    struct spu_context *ctx = file->private_data;
    unsigned int mask;

    poll_wait(file, &ctx->ibox_wq, wait);

    /*
     * For now keep this uninterruptible and also ignore the rule
     * that poll should not sleep.  Will be fixed later.
     */
    mutex_lock(&ctx->state_mutex);
    mask = ctx->ops->mbox_stat_poll(ctx, POLLIN | POLLRDNORM);
    spu_release(ctx);

    return mask;
}

static const struct file_operations spufs_ibox_fops = {
    .open   = spufs_pipe_open,
    .read   = spufs_ibox_read,
    .poll   = spufs_ibox_poll,
    .fasync = spufs_ibox_fasync,
    .llseek = no_llseek,
};

static ssize_t spufs_ibox_stat_read(struct file *file, char __user *buf,
            size_t len, loff_t *pos)
{
    struct spu_context *ctx = file->private_data;
    ssize_t ret;
    u32 ibox_stat;

    if (len < 4)
        return -EINVAL;

    ret = spu_acquire(ctx);
    if (ret)
        return ret;
    ibox_stat = (ctx->ops->mbox_stat_read(ctx) >> 16) & 0xff;
    spu_release(ctx);

    if (copy_to_user(buf, &ibox_stat, sizeof ibox_stat))
        return -EFAULT;

    return 4;
}

static const struct file_operations spufs_ibox_stat_fops = {
    .open   = spufs_pipe_open,
    .read   = spufs_ibox_stat_read,
    .llseek = no_llseek,
};

/* low-level mailbox write */
size_t spu_wbox_write(struct spu_context *ctx, u32 data)
{
    return ctx->ops->wbox_write(ctx, data);
}

static int spufs_wbox_fasync(int fd, struct file *file, int on)
{
    struct spu_context *ctx = file->private_data;
    int ret;

    ret = fasync_helper(fd, file, on, &ctx->wbox_fasync);

    return ret;
}

/* interrupt-level wbox callback function. */
void spufs_wbox_callback(struct spu *spu)
{
    struct spu_context *ctx = spu->ctx;

    if (!ctx)
        return;

    wake_up_all(&ctx->wbox_wq);
    kill_fasync(&ctx->wbox_fasync, SIGIO, POLLOUT);
}

/*
 * Write as many bytes to the interrupt mailbox as possible, until
 * one of the conditions becomes true:
 *
 * - the mailbox is full
 * - end of the user provided buffer
 * - end of the mapped area
 *
 * If the file is opened without O_NONBLOCK, we wait here until
 * space is availabyl, but return when we have been able to
 * write something.
 */
static ssize_t spufs_wbox_write(struct file *file, const char __user *buf,
            size_t len, loff_t *pos)
{
    struct spu_context *ctx = file->private_data;
    u32 wbox_data, __user *udata;
    ssize_t count;

    if (len < 4)
        return -EINVAL;

    udata = (void __user *)buf;
    if (!access_ok(VERIFY_READ, buf, len))
        return -EFAULT;

    if (__get_user(wbox_data, udata))
        return -EFAULT;

    count = spu_acquire(ctx);
    if (count)
        goto out;

    /*
     * make sure we can at least write one element, by waiting
     * in case of !O_NONBLOCK
     */
    count = 0;
    if (file->f_flags & O_NONBLOCK) {
        if (!spu_wbox_write(ctx, wbox_data)) {
            count = -EAGAIN;
            goto out_unlock;
        }
    } else {
        count = spufs_wait(ctx->wbox_wq, spu_wbox_write(ctx, wbox_data));
        if (count)
            goto out;
    }


    /* write as much as possible */
    for (count = 4, udata++; (count + 4) <= len; count += 4, udata++) {
        int ret;
        ret = __get_user(wbox_data, udata);
        if (ret)
            break;

        ret = spu_wbox_write(ctx, wbox_data);
        if (ret == 0)
            break;
    }

out_unlock:
    spu_release(ctx);
out:
    return count;
}

static unsigned int spufs_wbox_poll(struct file *file, poll_table *wait)
{
    struct spu_context *ctx = file->private_data;
    unsigned int mask;

    poll_wait(file, &ctx->wbox_wq, wait);

    /*
     * For now keep this uninterruptible and also ignore the rule
     * that poll should not sleep.  Will be fixed later.
     */
    mutex_lock(&ctx->state_mutex);
    mask = ctx->ops->mbox_stat_poll(ctx, POLLOUT | POLLWRNORM);
    spu_release(ctx);

    return mask;
}

static const struct file_operations spufs_wbox_fops = {
    .open   = spufs_pipe_open,
    .write  = spufs_wbox_write,
    .poll   = spufs_wbox_poll,
    .fasync = spufs_wbox_fasync,
    .llseek = no_llseek,
};

static ssize_t spufs_wbox_stat_read(struct file *file, char __user *buf,
            size_t len, loff_t *pos)
{
    struct spu_context *ctx = file->private_data;
    ssize_t ret;
    u32 wbox_stat;

    if (len < 4)
        return -EINVAL;

    ret = spu_acquire(ctx);
    if (ret)
        return ret;
    wbox_stat = (ctx->ops->mbox_stat_read(ctx) >> 8) & 0xff;
    spu_release(ctx);

    if (copy_to_user(buf, &wbox_stat, sizeof wbox_stat))
        return -EFAULT;

    return 4;
}

static const struct file_operations spufs_wbox_stat_fops = {
    .open   = spufs_pipe_open,
    .read   = spufs_wbox_stat_read,
    .llseek = no_llseek,
};

static int spufs_signal1_open(struct inode *inode, struct file *file)
{
    struct spufs_inode_info *i = SPUFS_I(inode);
    struct spu_context *ctx = i->i_ctx;

    mutex_lock(&ctx->mapping_lock);
    file->private_data = ctx;
    if (!i->i_openers++)
        ctx->signal1 = inode->i_mapping;
    mutex_unlock(&ctx->mapping_lock);
    return nonseekable_open(inode, file);
}

static int
spufs_signal1_release(struct inode *inode, struct file *file)
{
    struct spufs_inode_info *i = SPUFS_I(inode);
    struct spu_context *ctx = i->i_ctx;

    mutex_lock(&ctx->mapping_lock);
    if (!--i->i_openers)
        ctx->signal1 = NULL;
    mutex_unlock(&ctx->mapping_lock);
    return 0;
}

static ssize_t __spufs_signal1_read(struct spu_context *ctx, char __user *buf,
            size_t len, loff_t *pos)
{
    int ret = 0;
    u32 data;

    if (len < 4)
        return -EINVAL;

    if (ctx->csa.spu_chnlcnt_RW[3]) {
        data = ctx->csa.spu_chnldata_RW[3];
        ret = 4;
    }

    if (!ret)
        goto out;

    if (copy_to_user(buf, &data, 4))
        return -EFAULT;

out:
    return ret;
}

static ssize_t spufs_signal1_read(struct file *file, char __user *buf,
            size_t len, loff_t *pos)
{
    int ret;
    struct spu_context *ctx = file->private_data;

    ret = spu_acquire_saved(ctx);
    if (ret)
        return ret;
    ret = __spufs_signal1_read(ctx, buf, len, pos);
    spu_release_saved(ctx);

    return ret;
}

static ssize_t spufs_signal1_write(struct file *file, const char __user *buf,
            size_t len, loff_t *pos)
{
    struct spu_context *ctx;
    ssize_t ret;
    u32 data;

    ctx = file->private_data;

    if (len < 4)
        return -EINVAL;

    if (copy_from_user(&data, buf, 4))
        return -EFAULT;

    ret = spu_acquire(ctx);
    if (ret)
        return ret;
    ctx->ops->signal1_write(ctx, data);
    spu_release(ctx);

    return 4;
}

static int
spufs_signal1_mmap_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
{
#if SPUFS_SIGNAL_MAP_SIZE == 0x1000
    return spufs_ps_fault(vma, vmf, 0x14000, SPUFS_SIGNAL_MAP_SIZE);
#elif SPUFS_SIGNAL_MAP_SIZE == 0x10000
    /* For 64k pages, both signal1 and signal2 can be used to mmap the whole
     * signal 1 and 2 area
     */
    return spufs_ps_fault(vma, vmf, 0x10000, SPUFS_SIGNAL_MAP_SIZE);
#else
#error unsupported page size
#endif
}

static const struct vm_operations_struct spufs_signal1_mmap_vmops = {
    .fault = spufs_signal1_mmap_fault,
};

static int spufs_signal1_mmap(struct file *file, struct vm_area_struct *vma)
{
    if (!(vma->vm_flags & VM_SHARED))
        return -EINVAL;

    vma->vm_flags |= VM_IO | VM_PFNMAP;
    vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);

    vma->vm_ops = &spufs_signal1_mmap_vmops;
    return 0;
}

static const struct file_operations spufs_signal1_fops = {
    .open = spufs_signal1_open,
    .release = spufs_signal1_release,
    .read = spufs_signal1_read,
    .write = spufs_signal1_write,
    .mmap = spufs_signal1_mmap,
    .llseek = no_llseek,
};

static const struct file_operations spufs_signal1_nosched_fops = {
    .open = spufs_signal1_open,
    .release = spufs_signal1_release,
    .write = spufs_signal1_write,
    .mmap = spufs_signal1_mmap,
    .llseek = no_llseek,
};

static int spufs_signal2_open(struct inode *inode, struct file *file)
{
    struct spufs_inode_info *i = SPUFS_I(inode);
    struct spu_context *ctx = i->i_ctx;

    mutex_lock(&ctx->mapping_lock);
    file->private_data = ctx;
    if (!i->i_openers++)
        ctx->signal2 = inode->i_mapping;
    mutex_unlock(&ctx->mapping_lock);
    return nonseekable_open(inode, file);
}

static int
spufs_signal2_release(struct inode *inode, struct file *file)
{
    struct spufs_inode_info *i = SPUFS_I(inode);
    struct spu_context *ctx = i->i_ctx;

    mutex_lock(&ctx->mapping_lock);
    if (!--i->i_openers)
        ctx->signal2 = NULL;
    mutex_unlock(&ctx->mapping_lock);
    return 0;
}

static ssize_t __spufs_signal2_read(struct spu_context *ctx, char __user *buf,
            size_t len, loff_t *pos)
{
    int ret = 0;
    u32 data;

    if (len < 4)
        return -EINVAL;

    if (ctx->csa.spu_chnlcnt_RW[4]) {
        data =  ctx->csa.spu_chnldata_RW[4];
        ret = 4;
    }

    if (!ret)
        goto out;

    if (copy_to_user(buf, &data, 4))
        return -EFAULT;

out:
    return ret;
}

static ssize_t spufs_signal2_read(struct file *file, char __user *buf,
            size_t len, loff_t *pos)
{
    struct spu_context *ctx = file->private_data;
    int ret;

    ret = spu_acquire_saved(ctx);
    if (ret)
        return ret;
    ret = __spufs_signal2_read(ctx, buf, len, pos);
    spu_release_saved(ctx);

    return ret;
}

static ssize_t spufs_signal2_write(struct file *file, const char __user *buf,
            size_t len, loff_t *pos)
{
    struct spu_context *ctx;
    ssize_t ret;
    u32 data;

    ctx = file->private_data;

    if (len < 4)
        return -EINVAL;

    if (copy_from_user(&data, buf, 4))
        return -EFAULT;

    ret = spu_acquire(ctx);
    if (ret)
        return ret;
    ctx->ops->signal2_write(ctx, data);
    spu_release(ctx);

    return 4;
}

#if SPUFS_MMAP_4K
static int
spufs_signal2_mmap_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
{
#if SPUFS_SIGNAL_MAP_SIZE == 0x1000
    return spufs_ps_fault(vma, vmf, 0x1c000, SPUFS_SIGNAL_MAP_SIZE);
#elif SPUFS_SIGNAL_MAP_SIZE == 0x10000
    /* For 64k pages, both signal1 and signal2 can be used to mmap the whole
     * signal 1 and 2 area
     */
    return spufs_ps_fault(vma, vmf, 0x10000, SPUFS_SIGNAL_MAP_SIZE);
#else
#error unsupported page size
#endif
}

static const struct vm_operations_struct spufs_signal2_mmap_vmops = {
    .fault = spufs_signal2_mmap_fault,
};

static int spufs_signal2_mmap(struct file *file, struct vm_area_struct *vma)
{
    if (!(vma->vm_flags & VM_SHARED))
        return -EINVAL;

    vma->vm_flags |= VM_IO | VM_PFNMAP;
    vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);

    vma->vm_ops = &spufs_signal2_mmap_vmops;
    return 0;
}
#else /* SPUFS_MMAP_4K */
#define spufs_signal2_mmap NULL
#endif /* !SPUFS_MMAP_4K */

static const struct file_operations spufs_signal2_fops = {
    .open = spufs_signal2_open,
    .release = spufs_signal2_release,
    .read = spufs_signal2_read,
    .write = spufs_signal2_write,
    .mmap = spufs_signal2_mmap,
    .llseek = no_llseek,
};

static const struct file_operations spufs_signal2_nosched_fops = {
    .open = spufs_signal2_open,
    .release = spufs_signal2_release,
    .write = spufs_signal2_write,
    .mmap = spufs_signal2_mmap,
    .llseek = no_llseek,
};

/*
 * This is a wrapper around DEFINE_SIMPLE_ATTRIBUTE which does the
 * work of acquiring (or not) the SPU context before calling through
 * to the actual get routine. The set routine is called directly.
 */
#define SPU_ATTR_NOACQUIRE  0
#define SPU_ATTR_ACQUIRE    1
#define SPU_ATTR_ACQUIRE_SAVED  2

#define DEFINE_SPUFS_ATTRIBUTE(__name, __get, __set, __fmt, __acquire)  \
static int __##__get(void *data, u64 *val)              \
{                                   \
    struct spu_context *ctx = data;                 \
    int ret = 0;                            \
                                    \
    if (__acquire == SPU_ATTR_ACQUIRE) {                \
        ret = spu_acquire(ctx);                 \
        if (ret)                        \
            return ret;                 \
        *val = __get(ctx);                  \
        spu_release(ctx);                   \
    } else if (__acquire == SPU_ATTR_ACQUIRE_SAVED) {       \
        ret = spu_acquire_saved(ctx);               \
        if (ret)                        \
            return ret;                 \
        *val = __get(ctx);                  \
        spu_release_saved(ctx);                 \
    } else                              \
        *val = __get(ctx);                  \
                                    \
    return 0;                           \
}                                   \
DEFINE_SPUFS_SIMPLE_ATTRIBUTE(__name, __##__get, __set, __fmt);

static int spufs_signal1_type_set(void *data, u64 val)
{
    struct spu_context *ctx = data;
    int ret;

    ret = spu_acquire(ctx);
    if (ret)
        return ret;
    ctx->ops->signal1_type_set(ctx, val);
    spu_release(ctx);

    return 0;
}

static u64 spufs_signal1_type_get(struct spu_context *ctx)
{
    return ctx->ops->signal1_type_get(ctx);
}
DEFINE_SPUFS_ATTRIBUTE(spufs_signal1_type, spufs_signal1_type_get,
               spufs_signal1_type_set, "%llu\n", SPU_ATTR_ACQUIRE);


static int spufs_signal2_type_set(void *data, u64 val)
{
    struct spu_context *ctx = data;
    int ret;

    ret = spu_acquire(ctx);
    if (ret)
        return ret;
    ctx->ops->signal2_type_set(ctx, val);
    spu_release(ctx);

    return 0;
}

static u64 spufs_signal2_type_get(struct spu_context *ctx)
{
    return ctx->ops->signal2_type_get(ctx);
}
DEFINE_SPUFS_ATTRIBUTE(spufs_signal2_type, spufs_signal2_type_get,
               spufs_signal2_type_set, "%llu\n", SPU_ATTR_ACQUIRE);

#if SPUFS_MMAP_4K
static int
spufs_mss_mmap_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
{
    return spufs_ps_fault(vma, vmf, 0x0000, SPUFS_MSS_MAP_SIZE);
}

static const struct vm_operations_struct spufs_mss_mmap_vmops = {
    .fault = spufs_mss_mmap_fault,
};

/*
 * mmap support for problem state MFC DMA area [0x0000 - 0x0fff].
 */
static int spufs_mss_mmap(struct file *file, struct vm_area_struct *vma)
{
    if (!(vma->vm_flags & VM_SHARED))
        return -EINVAL;

    vma->vm_flags |= VM_IO | VM_PFNMAP;
    vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);

    vma->vm_ops = &spufs_mss_mmap_vmops;
    return 0;
}
#else /* SPUFS_MMAP_4K */
#define spufs_mss_mmap NULL
#endif /* !SPUFS_MMAP_4K */

static int spufs_mss_open(struct inode *inode, struct file *file)
{
    struct spufs_inode_info *i = SPUFS_I(inode);
    struct spu_context *ctx = i->i_ctx;

    file->private_data = i->i_ctx;

    mutex_lock(&ctx->mapping_lock);
    if (!i->i_openers++)
        ctx->mss = inode->i_mapping;
    mutex_unlock(&ctx->mapping_lock);
    return nonseekable_open(inode, file);
}

static int
spufs_mss_release(struct inode *inode, struct file *file)
{
    struct spufs_inode_info *i = SPUFS_I(inode);
    struct spu_context *ctx = i->i_ctx;

    mutex_lock(&ctx->mapping_lock);
    if (!--i->i_openers)
        ctx->mss = NULL;
    mutex_unlock(&ctx->mapping_lock);
    return 0;
}

static const struct file_operations spufs_mss_fops = {
    .open    = spufs_mss_open,
    .release = spufs_mss_release,
    .mmap    = spufs_mss_mmap,
    .llseek  = no_llseek,
};

static int
spufs_psmap_mmap_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
{
    return spufs_ps_fault(vma, vmf, 0x0000, SPUFS_PS_MAP_SIZE);
}

static const struct vm_operations_struct spufs_psmap_mmap_vmops = {
    .fault = spufs_psmap_mmap_fault,
};

/*
 * mmap support for full problem state area [0x00000 - 0x1ffff].
 */
static int spufs_psmap_mmap(struct file *file, struct vm_area_struct *vma)
{
    if (!(vma->vm_flags & VM_SHARED))
        return -EINVAL;

    vma->vm_flags |= VM_IO | VM_PFNMAP;
    vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);

    vma->vm_ops = &spufs_psmap_mmap_vmops;
    return 0;
}

static int spufs_psmap_open(struct inode *inode, struct file *file)
{
    struct spufs_inode_info *i = SPUFS_I(inode);
    struct spu_context *ctx = i->i_ctx;

    mutex_lock(&ctx->mapping_lock);
    file->private_data = i->i_ctx;
    if (!i->i_openers++)
        ctx->psmap = inode->i_mapping;
    mutex_unlock(&ctx->mapping_lock);
    return nonseekable_open(inode, file);
}

static int
spufs_psmap_release(struct inode *inode, struct file *file)
{
    struct spufs_inode_info *i = SPUFS_I(inode);
    struct spu_context *ctx = i->i_ctx;

    mutex_lock(&ctx->mapping_lock);
    if (!--i->i_openers)
        ctx->psmap = NULL;
    mutex_unlock(&ctx->mapping_lock);
    return 0;
}

static const struct file_operations spufs_psmap_fops = {
    .open    = spufs_psmap_open,
    .release = spufs_psmap_release,
    .mmap    = spufs_psmap_mmap,
    .llseek  = no_llseek,
};


#if SPUFS_MMAP_4K
static int
spufs_mfc_mmap_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
{
    return spufs_ps_fault(vma, vmf, 0x3000, SPUFS_MFC_MAP_SIZE);
}

static const struct vm_operations_struct spufs_mfc_mmap_vmops = {
    .fault = spufs_mfc_mmap_fault,
};

/*
 * mmap support for problem state MFC DMA area [0x0000 - 0x0fff].
 */
static int spufs_mfc_mmap(struct file *file, struct vm_area_struct *vma)
{
    if (!(vma->vm_flags & VM_SHARED))
        return -EINVAL;

    vma->vm_flags |= VM_IO | VM_PFNMAP;
    vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);

    vma->vm_ops = &spufs_mfc_mmap_vmops;
    return 0;
}
#else /* SPUFS_MMAP_4K */
#define spufs_mfc_mmap NULL
#endif /* !SPUFS_MMAP_4K */

static int spufs_mfc_open(struct inode *inode, struct file *file)
{
    struct spufs_inode_info *i = SPUFS_I(inode);
    struct spu_context *ctx = i->i_ctx;

    /* we don't want to deal with DMA into other processes */
    if (ctx->owner != current->mm)
        return -EINVAL;

    if (atomic_read(&inode->i_count) != 1)
        return -EBUSY;

    mutex_lock(&ctx->mapping_lock);
    file->private_data = ctx;
    if (!i->i_openers++)
        ctx->mfc = inode->i_mapping;
    mutex_unlock(&ctx->mapping_lock);
    return nonseekable_open(inode, file);
}

static int
spufs_mfc_release(struct inode *inode, struct file *file)
{
    struct spufs_inode_info *i = SPUFS_I(inode);
    struct spu_context *ctx = i->i_ctx;

    mutex_lock(&ctx->mapping_lock);
    if (!--i->i_openers)
        ctx->mfc = NULL;
    mutex_unlock(&ctx->mapping_lock);
    return 0;
}

/* interrupt-level mfc callback function. */
void spufs_mfc_callback(struct spu *spu)
{
    struct spu_context *ctx = spu->ctx;

    if (!ctx)
        return;

    wake_up_all(&ctx->mfc_wq);

    pr_debug("%s %s\n", __func__, spu->name);
    if (ctx->mfc_fasync) {
        u32 free_elements, tagstatus;
        unsigned int mask;

        /* no need for spu_acquire in interrupt context */
        free_elements = ctx->ops->get_mfc_free_elements(ctx);
        tagstatus = ctx->ops->read_mfc_tagstatus(ctx);

        mask = 0;
        if (free_elements & 0xffff)
            mask |= POLLOUT;
        if (tagstatus & ctx->tagwait)
            mask |= POLLIN;

        kill_fasync(&ctx->mfc_fasync, SIGIO, mask);
    }
}

static int spufs_read_mfc_tagstatus(struct spu_context *ctx, u32 *status)
{
    /* See if there is one tag group is complete */
    /* FIXME we need locking around tagwait */
    *status = ctx->ops->read_mfc_tagstatus(ctx) & ctx->tagwait;
    ctx->tagwait &= ~*status;
    if (*status)
        return 1;

    /* enable interrupt waiting for any tag group,
       may silently fail if interrupts are already enabled */
    ctx->ops->set_mfc_query(ctx, ctx->tagwait, 1);
    return 0;
}

static ssize_t spufs_mfc_read(struct file *file, char __user *buffer,
            size_t size, loff_t *pos)
{
    struct spu_context *ctx = file->private_data;
    int ret = -EINVAL;
    u32 status;

    if (size != 4)
        goto out;

    ret = spu_acquire(ctx);
    if (ret)
        return ret;

    ret = -EINVAL;
    if (file->f_flags & O_NONBLOCK) {
        status = ctx->ops->read_mfc_tagstatus(ctx);
        if (!(status & ctx->tagwait))
            ret = -EAGAIN;
        else
            /* XXX(hch): shouldn't we clear ret here? */
            ctx->tagwait &= ~status;
    } else {
        ret = spufs_wait(ctx->mfc_wq,
               spufs_read_mfc_tagstatus(ctx, &status));
        if (ret)
            goto out;
    }
    spu_release(ctx);

    ret = 4;
    if (copy_to_user(buffer, &status, 4))
        ret = -EFAULT;

out:
    return ret;
}

static int spufs_check_valid_dma(struct mfc_dma_command *cmd)
{
    pr_debug("queueing DMA %x %llx %x %x %x\n", cmd->lsa,
         cmd->ea, cmd->size, cmd->tag, cmd->cmd);

    switch (cmd->cmd) {
    case MFC_PUT_CMD:
    case MFC_PUTF_CMD:
    case MFC_PUTB_CMD:
    case MFC_GET_CMD:
    case MFC_GETF_CMD:
    case MFC_GETB_CMD:
        break;
    default:
        pr_debug("invalid DMA opcode %x\n", cmd->cmd);
        return -EIO;
    }

    if ((cmd->lsa & 0xf) != (cmd->ea &0xf)) {
        pr_debug("invalid DMA alignment, ea %llx lsa %x\n",
                cmd->ea, cmd->lsa);
        return -EIO;
    }

    switch (cmd->size & 0xf) {
    case 1:
        break;
    case 2:
        if (cmd->lsa & 1)
            goto error;
        break;
    case 4:
        if (cmd->lsa & 3)
            goto error;
        break;
    case 8:
        if (cmd->lsa & 7)
            goto error;
        break;
    case 0:
        if (cmd->lsa & 15)
            goto error;
        break;
    error:
    default:
        pr_debug("invalid DMA alignment %x for size %x\n",
            cmd->lsa & 0xf, cmd->size);
        return -EIO;
    }

    if (cmd->size > 16 * 1024) {
        pr_debug("invalid DMA size %x\n", cmd->size);
        return -EIO;
    }

    if (cmd->tag & 0xfff0) {
        /* we reserve the higher tag numbers for kernel use */
        pr_debug("invalid DMA tag\n");
        return -EIO;
    }

    if (cmd->class) {
        /* not supported in this version */
        pr_debug("invalid DMA class\n");
        return -EIO;
    }

    return 0;
}

static int spu_send_mfc_command(struct spu_context *ctx,
                struct mfc_dma_command cmd,
                int *error)
{
    *error = ctx->ops->send_mfc_command(ctx, &cmd);
    if (*error == -EAGAIN) {
        /* wait for any tag group to complete
           so we have space for the new command */
        ctx->ops->set_mfc_query(ctx, ctx->tagwait, 1);
        /* try again, because the queue might be
           empty again */
        *error = ctx->ops->send_mfc_command(ctx, &cmd);
        if (*error == -EAGAIN)
            return 0;
    }
    return 1;
}

static ssize_t spufs_mfc_write(struct file *file, const char __user *buffer,
            size_t size, loff_t *pos)
{
    struct spu_context *ctx = file->private_data;
    struct mfc_dma_command cmd;
    int ret = -EINVAL;

    if (size != sizeof cmd)
        goto out;

    ret = -EFAULT;
    if (copy_from_user(&cmd, buffer, sizeof cmd))
        goto out;

    ret = spufs_check_valid_dma(&cmd);
    if (ret)
        goto out;

    ret = spu_acquire(ctx);
    if (ret)
        goto out;

    ret = spufs_wait(ctx->run_wq, ctx->state == SPU_STATE_RUNNABLE);
    if (ret)
        goto out;

    if (file->f_flags & O_NONBLOCK) {
        ret = ctx->ops->send_mfc_command(ctx, &cmd);
    } else {
        int status;
        ret = spufs_wait(ctx->mfc_wq,
                 spu_send_mfc_command(ctx, cmd, &status));
        if (ret)
            goto out;
        if (status)
            ret = status;
    }

    if (ret)
        goto out_unlock;

    ctx->tagwait |= 1 << cmd.tag;
    ret = size;

out_unlock:
    spu_release(ctx);
out:
    return ret;
}

static unsigned int spufs_mfc_poll(struct file *file,poll_table *wait)
{
    struct spu_context *ctx = file->private_data;
    u32 free_elements, tagstatus;
    unsigned int mask;

    poll_wait(file, &ctx->mfc_wq, wait);

    /*
     * For now keep this uninterruptible and also ignore the rule
     * that poll should not sleep.  Will be fixed later.
     */
    mutex_lock(&ctx->state_mutex);
    ctx->ops->set_mfc_query(ctx, ctx->tagwait, 2);
    free_elements = ctx->ops->get_mfc_free_elements(ctx);
    tagstatus = ctx->ops->read_mfc_tagstatus(ctx);
    spu_release(ctx);

    mask = 0;
    if (free_elements & 0xffff)
        mask |= POLLOUT | POLLWRNORM;
    if (tagstatus & ctx->tagwait)
        mask |= POLLIN | POLLRDNORM;

    pr_debug("%s: free %d tagstatus %d tagwait %d\n", __func__,
        free_elements, tagstatus, ctx->tagwait);

    return mask;
}

static int spufs_mfc_flush(struct file *file, fl_owner_t id)
{
    struct spu_context *ctx = file->private_data;
    int ret;

    ret = spu_acquire(ctx);
    if (ret)
        goto out;
#if 0
/* this currently hangs */
    ret = spufs_wait(ctx->mfc_wq,
             ctx->ops->set_mfc_query(ctx, ctx->tagwait, 2));
    if (ret)
        goto out;
    ret = spufs_wait(ctx->mfc_wq,
             ctx->ops->read_mfc_tagstatus(ctx) == ctx->tagwait);
    if (ret)
        goto out;
#else
    ret = 0;
#endif
    spu_release(ctx);
out:
    return ret;
}

static int spufs_mfc_fsync(struct file *file, loff_t start, loff_t end, int datasync)
{
    struct inode *inode = file->f_path.dentry->d_inode;
    int err = filemap_write_and_wait_range(inode->i_mapping, start, end);
    if (!err) {
        mutex_lock(&inode->i_mutex);
        err = spufs_mfc_flush(file, NULL);
        mutex_unlock(&inode->i_mutex);
    }
    return err;
}

static int spufs_mfc_fasync(int fd, struct file *file, int on)
{
    struct spu_context *ctx = file->private_data;

    return fasync_helper(fd, file, on, &ctx->mfc_fasync);
}

static const struct file_operations spufs_mfc_fops = {
    .open    = spufs_mfc_open,
    .release = spufs_mfc_release,
    .read    = spufs_mfc_read,
    .write   = spufs_mfc_write,
    .poll    = spufs_mfc_poll,
    .flush   = spufs_mfc_flush,
    .fsync   = spufs_mfc_fsync,
    .fasync  = spufs_mfc_fasync,
    .mmap    = spufs_mfc_mmap,
    .llseek  = no_llseek,
};

static int spufs_npc_set(void *data, u64 val)
{
    struct spu_context *ctx = data;
    int ret;

    ret = spu_acquire(ctx);
    if (ret)
        return ret;
    ctx->ops->npc_write(ctx, val);
    spu_release(ctx);

    return 0;
}

static u64 spufs_npc_get(struct spu_context *ctx)
{
    return ctx->ops->npc_read(ctx);
}
DEFINE_SPUFS_ATTRIBUTE(spufs_npc_ops, spufs_npc_get, spufs_npc_set,
               "0x%llx\n", SPU_ATTR_ACQUIRE);

static int spufs_decr_set(void *data, u64 val)
{
    struct spu_context *ctx = data;
    struct spu_lscsa *lscsa = ctx->csa.lscsa;
    int ret;

    ret = spu_acquire_saved(ctx);
    if (ret)
        return ret;
    lscsa->decr.slot[0] = (u32) val;
    spu_release_saved(ctx);

    return 0;
}

static u64 spufs_decr_get(struct spu_context *ctx)
{
    struct spu_lscsa *lscsa = ctx->csa.lscsa;
    return lscsa->decr.slot[0];
}
DEFINE_SPUFS_ATTRIBUTE(spufs_decr_ops, spufs_decr_get, spufs_decr_set,
               "0x%llx\n", SPU_ATTR_ACQUIRE_SAVED);

static int spufs_decr_status_set(void *data, u64 val)
{
    struct spu_context *ctx = data;
    int ret;

    ret = spu_acquire_saved(ctx);
    if (ret)
        return ret;
    if (val)
        ctx->csa.priv2.mfc_control_RW |= MFC_CNTL_DECREMENTER_RUNNING;
    else
        ctx->csa.priv2.mfc_control_RW &= ~MFC_CNTL_DECREMENTER_RUNNING;
    spu_release_saved(ctx);

    return 0;
}

static u64 spufs_decr_status_get(struct spu_context *ctx)
{
    if (ctx->csa.priv2.mfc_control_RW & MFC_CNTL_DECREMENTER_RUNNING)
        return SPU_DECR_STATUS_RUNNING;
    else
        return 0;
}
DEFINE_SPUFS_ATTRIBUTE(spufs_decr_status_ops, spufs_decr_status_get,
               spufs_decr_status_set, "0x%llx\n",
               SPU_ATTR_ACQUIRE_SAVED);

static int spufs_event_mask_set(void *data, u64 val)
{
    struct spu_context *ctx = data;
    struct spu_lscsa *lscsa = ctx->csa.lscsa;
    int ret;

    ret = spu_acquire_saved(ctx);
    if (ret)
        return ret;
    lscsa->event_mask.slot[0] = (u32) val;
    spu_release_saved(ctx);

    return 0;
}

static u64 spufs_event_mask_get(struct spu_context *ctx)
{
    struct spu_lscsa *lscsa = ctx->csa.lscsa;
    return lscsa->event_mask.slot[0];
}

DEFINE_SPUFS_ATTRIBUTE(spufs_event_mask_ops, spufs_event_mask_get,
               spufs_event_mask_set, "0x%llx\n",
               SPU_ATTR_ACQUIRE_SAVED);

static u64 spufs_event_status_get(struct spu_context *ctx)
{
    struct spu_state *state = &ctx->csa;
    u64 stat;
    stat = state->spu_chnlcnt_RW[0];
    if (stat)
        return state->spu_chnldata_RW[0];
    return 0;
}
DEFINE_SPUFS_ATTRIBUTE(spufs_event_status_ops, spufs_event_status_get,
               NULL, "0x%llx\n", SPU_ATTR_ACQUIRE_SAVED)

static int spufs_srr0_set(void *data, u64 val)
{
    struct spu_context *ctx = data;
    struct spu_lscsa *lscsa = ctx->csa.lscsa;
    int ret;

    ret = spu_acquire_saved(ctx);
    if (ret)
        return ret;
    lscsa->srr0.slot[0] = (u32) val;
    spu_release_saved(ctx);

    return 0;
}

static u64 spufs_srr0_get(struct spu_context *ctx)
{
    struct spu_lscsa *lscsa = ctx->csa.lscsa;
    return lscsa->srr0.slot[0];
}
DEFINE_SPUFS_ATTRIBUTE(spufs_srr0_ops, spufs_srr0_get, spufs_srr0_set,
               "0x%llx\n", SPU_ATTR_ACQUIRE_SAVED)

static u64 spufs_id_get(struct spu_context *ctx)
{
    u64 num;

    if (ctx->state == SPU_STATE_RUNNABLE)
        num = ctx->spu->number;
    else
        num = (unsigned int)-1;

    return num;
}
DEFINE_SPUFS_ATTRIBUTE(spufs_id_ops, spufs_id_get, NULL, "0x%llx\n",
               SPU_ATTR_ACQUIRE)

static u64 spufs_object_id_get(struct spu_context *ctx)
{
    /* FIXME: Should there really be no locking here? */
    return ctx->object_id;
}

static int spufs_object_id_set(void *data, u64 id)
{
    struct spu_context *ctx = data;
    ctx->object_id = id;

    return 0;
}

DEFINE_SPUFS_ATTRIBUTE(spufs_object_id_ops, spufs_object_id_get,
               spufs_object_id_set, "0x%llx\n", SPU_ATTR_NOACQUIRE);

static u64 spufs_lslr_get(struct spu_context *ctx)
{
    return ctx->csa.priv2.spu_lslr_RW;
}
DEFINE_SPUFS_ATTRIBUTE(spufs_lslr_ops, spufs_lslr_get, NULL, "0x%llx\n",
               SPU_ATTR_ACQUIRE_SAVED);

static int spufs_info_open(struct inode *inode, struct file *file)
{
    struct spufs_inode_info *i = SPUFS_I(inode);
    struct spu_context *ctx = i->i_ctx;
    file->private_data = ctx;
    return 0;
}

static int spufs_caps_show(struct seq_file *s, void *private)
{
    struct spu_context *ctx = s->private;

    if (!(ctx->flags & SPU_CREATE_NOSCHED))
        seq_puts(s, "sched\n");
    if (!(ctx->flags & SPU_CREATE_ISOLATE))
        seq_puts(s, "step\n");
    return 0;
}

static int spufs_caps_open(struct inode *inode, struct file *file)
{
    return single_open(file, spufs_caps_show, SPUFS_I(inode)->i_ctx);
}

static const struct file_operations spufs_caps_fops = {
    .open       = spufs_caps_open,
    .read       = seq_read,
    .llseek     = seq_lseek,
    .release    = single_release,
};

static ssize_t __spufs_mbox_info_read(struct spu_context *ctx,
            char __user *buf, size_t len, loff_t *pos)
{
    u32 data;

    /* EOF if there's no entry in the mbox */
    if (!(ctx->csa.prob.mb_stat_R & 0x0000ff))
        return 0;

    data = ctx->csa.prob.pu_mb_R;

    return simple_read_from_buffer(buf, len, pos, &data, sizeof data);
}

static ssize_t spufs_mbox_info_read(struct file *file, char __user *buf,
                   size_t len, loff_t *pos)
{
    int ret;
    struct spu_context *ctx = file->private_data;

    if (!access_ok(VERIFY_WRITE, buf, len))
        return -EFAULT;

    ret = spu_acquire_saved(ctx);
    if (ret)
        return ret;
    spin_lock(&ctx->csa.register_lock);
    ret = __spufs_mbox_info_read(ctx, buf, len, pos);
    spin_unlock(&ctx->csa.register_lock);
    spu_release_saved(ctx);

    return ret;
}

static const struct file_operations spufs_mbox_info_fops = {
    .open = spufs_info_open,
    .read = spufs_mbox_info_read,
    .llseek  = generic_file_llseek,
};

static ssize_t __spufs_ibox_info_read(struct spu_context *ctx,
                char __user *buf, size_t len, loff_t *pos)
{
    u32 data;

    /* EOF if there's no entry in the ibox */
    if (!(ctx->csa.prob.mb_stat_R & 0xff0000))
        return 0;

    data = ctx->csa.priv2.puint_mb_R;

    return simple_read_from_buffer(buf, len, pos, &data, sizeof data);
}

static ssize_t spufs_ibox_info_read(struct file *file, char __user *buf,
                   size_t len, loff_t *pos)
{
    struct spu_context *ctx = file->private_data;
    int ret;

    if (!access_ok(VERIFY_WRITE, buf, len))
        return -EFAULT;

    ret = spu_acquire_saved(ctx);
    if (ret)
        return ret;
    spin_lock(&ctx->csa.register_lock);
    ret = __spufs_ibox_info_read(ctx, buf, len, pos);
    spin_unlock(&ctx->csa.register_lock);
    spu_release_saved(ctx);

    return ret;
}

static const struct file_operations spufs_ibox_info_fops = {
    .open = spufs_info_open,
    .read = spufs_ibox_info_read,
    .llseek  = generic_file_llseek,
};

static ssize_t __spufs_wbox_info_read(struct spu_context *ctx,
            char __user *buf, size_t len, loff_t *pos)
{
    int i, cnt;
    u32 data[4];
    u32 wbox_stat;

    wbox_stat = ctx->csa.prob.mb_stat_R;
    cnt = 4 - ((wbox_stat & 0x00ff00) >> 8);
    for (i = 0; i < cnt; i++) {
        data[i] = ctx->csa.spu_mailbox_data[i];
    }

    return simple_read_from_buffer(buf, len, pos, &data,
                cnt * sizeof(u32));
}

static ssize_t spufs_wbox_info_read(struct file *file, char __user *buf,
                   size_t len, loff_t *pos)
{
    struct spu_context *ctx = file->private_data;
    int ret;

    if (!access_ok(VERIFY_WRITE, buf, len))
        return -EFAULT;

    ret = spu_acquire_saved(ctx);
    if (ret)
        return ret;
    spin_lock(&ctx->csa.register_lock);
    ret = __spufs_wbox_info_read(ctx, buf, len, pos);
    spin_unlock(&ctx->csa.register_lock);
    spu_release_saved(ctx);

    return ret;
}

static const struct file_operations spufs_wbox_info_fops = {
    .open = spufs_info_open,
    .read = spufs_wbox_info_read,
    .llseek  = generic_file_llseek,
};

static ssize_t __spufs_dma_info_read(struct spu_context *ctx,
            char __user *buf, size_t len, loff_t *pos)
{
    struct spu_dma_info info;
    struct mfc_cq_sr *qp, *spuqp;
    int i;

    info.dma_info_type = ctx->csa.priv2.spu_tag_status_query_RW;
    info.dma_info_mask = ctx->csa.lscsa->tag_mask.slot[0];
    info.dma_info_status = ctx->csa.spu_chnldata_RW[24];
    info.dma_info_stall_and_notify = ctx->csa.spu_chnldata_RW[25];
    info.dma_info_atomic_command_status = ctx->csa.spu_chnldata_RW[27];
    for (i = 0; i < 16; i++) {
        qp = &info.dma_info_command_data[i];
        spuqp = &ctx->csa.priv2.spuq[i];

        qp->mfc_cq_data0_RW = spuqp->mfc_cq_data0_RW;
        qp->mfc_cq_data1_RW = spuqp->mfc_cq_data1_RW;
        qp->mfc_cq_data2_RW = spuqp->mfc_cq_data2_RW;
        qp->mfc_cq_data3_RW = spuqp->mfc_cq_data3_RW;
    }

    return simple_read_from_buffer(buf, len, pos, &info,
                sizeof info);
}

static ssize_t spufs_dma_info_read(struct file *file, char __user *buf,
                  size_t len, loff_t *pos)
{
    struct spu_context *ctx = file->private_data;
    int ret;

    if (!access_ok(VERIFY_WRITE, buf, len))
        return -EFAULT;

    ret = spu_acquire_saved(ctx);
    if (ret)
        return ret;
    spin_lock(&ctx->csa.register_lock);
    ret = __spufs_dma_info_read(ctx, buf, len, pos);
    spin_unlock(&ctx->csa.register_lock);
    spu_release_saved(ctx);

    return ret;
}

static const struct file_operations spufs_dma_info_fops = {
    .open = spufs_info_open,
    .read = spufs_dma_info_read,
    .llseek = no_llseek,
};

static ssize_t __spufs_proxydma_info_read(struct spu_context *ctx,
            char __user *buf, size_t len, loff_t *pos)
{
    struct spu_proxydma_info info;
    struct mfc_cq_sr *qp, *puqp;
    int ret = sizeof info;
    int i;

    if (len < ret)
        return -EINVAL;

    if (!access_ok(VERIFY_WRITE, buf, len))
        return -EFAULT;

    info.proxydma_info_type = ctx->csa.prob.dma_querytype_RW;
    info.proxydma_info_mask = ctx->csa.prob.dma_querymask_RW;
    info.proxydma_info_status = ctx->csa.prob.dma_tagstatus_R;
    for (i = 0; i < 8; i++) {
        qp = &info.proxydma_info_command_data[i];
        puqp = &ctx->csa.priv2.puq[i];

        qp->mfc_cq_data0_RW = puqp->mfc_cq_data0_RW;
        qp->mfc_cq_data1_RW = puqp->mfc_cq_data1_RW;
        qp->mfc_cq_data2_RW = puqp->mfc_cq_data2_RW;
        qp->mfc_cq_data3_RW = puqp->mfc_cq_data3_RW;
    }

    return simple_read_from_buffer(buf, len, pos, &info,
                sizeof info);
}

static ssize_t spufs_proxydma_info_read(struct file *file, char __user *buf,
                   size_t len, loff_t *pos)
{
    struct spu_context *ctx = file->private_data;
    int ret;

    ret = spu_acquire_saved(ctx);
    if (ret)
        return ret;
    spin_lock(&ctx->csa.register_lock);
    ret = __spufs_proxydma_info_read(ctx, buf, len, pos);
    spin_unlock(&ctx->csa.register_lock);
    spu_release_saved(ctx);

    return ret;
}

static const struct file_operations spufs_proxydma_info_fops = {
    .open = spufs_info_open,
    .read = spufs_proxydma_info_read,
    .llseek = no_llseek,
};

static int spufs_show_tid(struct seq_file *s, void *private)
{
    struct spu_context *ctx = s->private;

    seq_printf(s, "%d\n", ctx->tid);
    return 0;
}

static int spufs_tid_open(struct inode *inode, struct file *file)
{
    return single_open(file, spufs_show_tid, SPUFS_I(inode)->i_ctx);
}

static const struct file_operations spufs_tid_fops = {
    .open       = spufs_tid_open,
    .read       = seq_read,
    .llseek     = seq_lseek,
    .release    = single_release,
};

static const char *ctx_state_names[] = {
    "user", "system", "iowait", "loaded"
};

static unsigned long long spufs_acct_time(struct spu_context *ctx,
        enum spu_utilization_state state)
{
    struct timespec ts;
    unsigned long long time = ctx->stats.times[state];

    /*
     * In general, utilization statistics are updated by the controlling
     * thread as the spu context moves through various well defined
     * state transitions, but if the context is lazily loaded its
     * utilization statistics are not updated as the controlling thread
     * is not tightly coupled with the execution of the spu context.  We
     * calculate and apply the time delta from the last recorded state
     * of the spu context.
     */
    if (ctx->spu && ctx->stats.util_state == state) {
        ktime_get_ts(&ts);
        time += timespec_to_ns(&ts) - ctx->stats.tstamp;
    }

    return time / NSEC_PER_MSEC;
}

static unsigned long long spufs_slb_flts(struct spu_context *ctx)
{
    unsigned long long slb_flts = ctx->stats.slb_flt;

    if (ctx->state == SPU_STATE_RUNNABLE) {
        slb_flts += (ctx->spu->stats.slb_flt -
                 ctx->stats.slb_flt_base);
    }

    return slb_flts;
}

static unsigned long long spufs_class2_intrs(struct spu_context *ctx)
{
    unsigned long long class2_intrs = ctx->stats.class2_intr;

    if (ctx->state == SPU_STATE_RUNNABLE) {
        class2_intrs += (ctx->spu->stats.class2_intr -
                 ctx->stats.class2_intr_base);
    }

    return class2_intrs;
}


static int spufs_show_stat(struct seq_file *s, void *private)
{
    struct spu_context *ctx = s->private;
    int ret;

    ret = spu_acquire(ctx);
    if (ret)
        return ret;

    seq_printf(s, "%s %llu %llu %llu %llu "
              "%llu %llu %llu %llu %llu %llu %llu %llu\n",
        ctx_state_names[ctx->stats.util_state],
        spufs_acct_time(ctx, SPU_UTIL_USER),
        spufs_acct_time(ctx, SPU_UTIL_SYSTEM),
        spufs_acct_time(ctx, SPU_UTIL_IOWAIT),
        spufs_acct_time(ctx, SPU_UTIL_IDLE_LOADED),
        ctx->stats.vol_ctx_switch,
        ctx->stats.invol_ctx_switch,
        spufs_slb_flts(ctx),
        ctx->stats.hash_flt,
        ctx->stats.min_flt,
        ctx->stats.maj_flt,
        spufs_class2_intrs(ctx),
        ctx->stats.libassist);
    spu_release(ctx);
    return 0;
}

static int spufs_stat_open(struct inode *inode, struct file *file)
{
    return single_open(file, spufs_show_stat, SPUFS_I(inode)->i_ctx);
}

static const struct file_operations spufs_stat_fops = {
    .open       = spufs_stat_open,
    .read       = seq_read,
    .llseek     = seq_lseek,
    .release    = single_release,
};

static inline int spufs_switch_log_used(struct spu_context *ctx)
{
    return (ctx->switch_log->head - ctx->switch_log->tail) %
        SWITCH_LOG_BUFSIZE;
}

static inline int spufs_switch_log_avail(struct spu_context *ctx)
{
    return SWITCH_LOG_BUFSIZE - spufs_switch_log_used(ctx);
}

static int spufs_switch_log_open(struct inode *inode, struct file *file)
{
    struct spu_context *ctx = SPUFS_I(inode)->i_ctx;
    int rc;

    rc = spu_acquire(ctx);
    if (rc)
        return rc;

    if (ctx->switch_log) {
        rc = -EBUSY;
        goto out;
    }

    ctx->switch_log = kmalloc(sizeof(struct switch_log) +
        SWITCH_LOG_BUFSIZE * sizeof(struct switch_log_entry),
        GFP_KERNEL);

    if (!ctx->switch_log) {
        rc = -ENOMEM;
        goto out;
    }

    ctx->switch_log->head = ctx->switch_log->tail = 0;
    init_waitqueue_head(&ctx->switch_log->wait);
    rc = 0;

out:
    spu_release(ctx);
    return rc;
}

static int spufs_switch_log_release(struct inode *inode, struct file *file)
{
    struct spu_context *ctx = SPUFS_I(inode)->i_ctx;
    int rc;

    rc = spu_acquire(ctx);
    if (rc)
        return rc;

    kfree(ctx->switch_log);
    ctx->switch_log = NULL;
    spu_release(ctx);

    return 0;
}

static int switch_log_sprint(struct spu_context *ctx, char *tbuf, int n)
{
    struct switch_log_entry *p;

    p = ctx->switch_log->log + ctx->switch_log->tail % SWITCH_LOG_BUFSIZE;

    return snprintf(tbuf, n, "%u.%09u %d %u %u %llu\n",
            (unsigned int) p->tstamp.tv_sec,
            (unsigned int) p->tstamp.tv_nsec,
            p->spu_id,
            (unsigned int) p->type,
            (unsigned int) p->val,
            (unsigned long long) p->timebase);
}

static ssize_t spufs_switch_log_read(struct file *file, char __user *buf,
                 size_t len, loff_t *ppos)
{
    struct inode *inode = file->f_path.dentry->d_inode;
    struct spu_context *ctx = SPUFS_I(inode)->i_ctx;
    int error = 0, cnt = 0;

    if (!buf)
        return -EINVAL;

    error = spu_acquire(ctx);
    if (error)
        return error;

    while (cnt < len) {
        char tbuf[128];
        int width;

        if (spufs_switch_log_used(ctx) == 0) {
            if (cnt > 0) {
                /* If there's data ready to go, we can
                 * just return straight away */
                break;

            } else if (file->f_flags & O_NONBLOCK) {
                error = -EAGAIN;
                break;

            } else {
                /* spufs_wait will drop the mutex and
                 * re-acquire, but since we're in read(), the
                 * file cannot be _released (and so
                 * ctx->switch_log is stable).
                 */
                error = spufs_wait(ctx->switch_log->wait,
                        spufs_switch_log_used(ctx) > 0);

                /* On error, spufs_wait returns without the
                 * state mutex held */
                if (error)
                    return error;

                /* We may have had entries read from underneath
                 * us while we dropped the mutex in spufs_wait,
                 * so re-check */
                if (spufs_switch_log_used(ctx) == 0)
                    continue;
            }
        }

        width = switch_log_sprint(ctx, tbuf, sizeof(tbuf));
        if (width < len)
            ctx->switch_log->tail =
                (ctx->switch_log->tail + 1) %
                 SWITCH_LOG_BUFSIZE;
        else
            /* If the record is greater than space available return
             * partial buffer (so far) */
            break;

        error = copy_to_user(buf + cnt, tbuf, width);
        if (error)
            break;
        cnt += width;
    }

    spu_release(ctx);

    return cnt == 0 ? error : cnt;
}

static unsigned int spufs_switch_log_poll(struct file *file, poll_table *wait)
{
    struct inode *inode = file->f_path.dentry->d_inode;
    struct spu_context *ctx = SPUFS_I(inode)->i_ctx;
    unsigned int mask = 0;
    int rc;

    poll_wait(file, &ctx->switch_log->wait, wait);

    rc = spu_acquire(ctx);
    if (rc)
        return rc;

    if (spufs_switch_log_used(ctx) > 0)
        mask |= POLLIN;

    spu_release(ctx);

    return mask;
}

static const struct file_operations spufs_switch_log_fops = {
    .owner      = THIS_MODULE,
    .open       = spufs_switch_log_open,
    .read       = spufs_switch_log_read,
    .poll       = spufs_switch_log_poll,
    .release    = spufs_switch_log_release,
    .llseek     = no_llseek,
};

void spu_switch_log_notify(struct spu *spu, struct spu_context *ctx,
        u32 type, u32 val)
{
    if (!ctx->switch_log)
        return;

    if (spufs_switch_log_avail(ctx) > 1) {
        struct switch_log_entry *p;

        p = ctx->switch_log->log + ctx->switch_log->head;
        ktime_get_ts(&p->tstamp);
        p->timebase = get_tb();
        p->spu_id = spu ? spu->number : -1;
        p->type = type;
        p->val = val;

        ctx->switch_log->head =
            (ctx->switch_log->head + 1) % SWITCH_LOG_BUFSIZE;
    }

    wake_up(&ctx->switch_log->wait);
}

static int spufs_show_ctx(struct seq_file *s, void *private)
{
    struct spu_context *ctx = s->private;
    u64 mfc_control_RW;

    mutex_lock(&ctx->state_mutex);
    if (ctx->spu) {
        struct spu *spu = ctx->spu;
        struct spu_priv2 __iomem *priv2 = spu->priv2;

        spin_lock_irq(&spu->register_lock);
        mfc_control_RW = in_be64(&priv2->mfc_control_RW);
        spin_unlock_irq(&spu->register_lock);
    } else {
        struct spu_state *csa = &ctx->csa;

        mfc_control_RW = csa->priv2.mfc_control_RW;
    }

    seq_printf(s, "%c flgs(%lx) sflgs(%lx) pri(%d) ts(%d) spu(%02d)"
        " %c %llx %llx %llx %llx %x %x\n",
        ctx->state == SPU_STATE_SAVED ? 'S' : 'R',
        ctx->flags,
        ctx->sched_flags,
        ctx->prio,
        ctx->time_slice,
        ctx->spu ? ctx->spu->number : -1,
        !list_empty(&ctx->rq) ? 'q' : ' ',
        ctx->csa.class_0_pending,
        ctx->csa.class_0_dar,
        ctx->csa.class_1_dsisr,
        mfc_control_RW,
        ctx->ops->runcntl_read(ctx),
        ctx->ops->status_read(ctx));

    mutex_unlock(&ctx->state_mutex);

    return 0;
}

static int spufs_ctx_open(struct inode *inode, struct file *file)
{
    return single_open(file, spufs_show_ctx, SPUFS_I(inode)->i_ctx);
}

static const struct file_operations spufs_ctx_fops = {
    .open           = spufs_ctx_open,
    .read           = seq_read,
    .llseek         = seq_lseek,
    .release        = single_release,
};

const struct spufs_tree_descr spufs_dir_contents[] = {
    { "capabilities", &spufs_caps_fops, 0444, },
    { "mem",  &spufs_mem_fops,  0666, LS_SIZE, },
    { "regs", &spufs_regs_fops,  0666, sizeof(struct spu_reg128[128]), },
    { "mbox", &spufs_mbox_fops, 0444, },
    { "ibox", &spufs_ibox_fops, 0444, },
    { "wbox", &spufs_wbox_fops, 0222, },
    { "mbox_stat", &spufs_mbox_stat_fops, 0444, sizeof(u32), },
    { "ibox_stat", &spufs_ibox_stat_fops, 0444, sizeof(u32), },
    { "wbox_stat", &spufs_wbox_stat_fops, 0444, sizeof(u32), },
    { "signal1", &spufs_signal1_fops, 0666, },
    { "signal2", &spufs_signal2_fops, 0666, },
    { "signal1_type", &spufs_signal1_type, 0666, },
    { "signal2_type", &spufs_signal2_type, 0666, },
    { "cntl", &spufs_cntl_fops,  0666, },
    { "fpcr", &spufs_fpcr_fops, 0666, sizeof(struct spu_reg128), },
    { "lslr", &spufs_lslr_ops, 0444, },
    { "mfc", &spufs_mfc_fops, 0666, },
    { "mss", &spufs_mss_fops, 0666, },
    { "npc", &spufs_npc_ops, 0666, },
    { "srr0", &spufs_srr0_ops, 0666, },
    { "decr", &spufs_decr_ops, 0666, },
    { "decr_status", &spufs_decr_status_ops, 0666, },
    { "event_mask", &spufs_event_mask_ops, 0666, },
    { "event_status", &spufs_event_status_ops, 0444, },
    { "psmap", &spufs_psmap_fops, 0666, SPUFS_PS_MAP_SIZE, },
    { "phys-id", &spufs_id_ops, 0666, },
    { "object-id", &spufs_object_id_ops, 0666, },
    { "mbox_info", &spufs_mbox_info_fops, 0444, sizeof(u32), },
    { "ibox_info", &spufs_ibox_info_fops, 0444, sizeof(u32), },
    { "wbox_info", &spufs_wbox_info_fops, 0444, sizeof(u32), },
    { "dma_info", &spufs_dma_info_fops, 0444,
        sizeof(struct spu_dma_info), },
    { "proxydma_info", &spufs_proxydma_info_fops, 0444,
        sizeof(struct spu_proxydma_info)},
    { "tid", &spufs_tid_fops, 0444, },
    { "stat", &spufs_stat_fops, 0444, },
    { "switch_log", &spufs_switch_log_fops, 0444 },
    {},
};

const struct spufs_tree_descr spufs_dir_nosched_contents[] = {
    { "capabilities", &spufs_caps_fops, 0444, },
    { "mem",  &spufs_mem_fops,  0666, LS_SIZE, },
    { "mbox", &spufs_mbox_fops, 0444, },
    { "ibox", &spufs_ibox_fops, 0444, },
    { "wbox", &spufs_wbox_fops, 0222, },
    { "mbox_stat", &spufs_mbox_stat_fops, 0444, sizeof(u32), },
    { "ibox_stat", &spufs_ibox_stat_fops, 0444, sizeof(u32), },
    { "wbox_stat", &spufs_wbox_stat_fops, 0444, sizeof(u32), },
    { "signal1", &spufs_signal1_nosched_fops, 0222, },
    { "signal2", &spufs_signal2_nosched_fops, 0222, },
    { "signal1_type", &spufs_signal1_type, 0666, },
    { "signal2_type", &spufs_signal2_type, 0666, },
    { "mss", &spufs_mss_fops, 0666, },
    { "mfc", &spufs_mfc_fops, 0666, },
    { "cntl", &spufs_cntl_fops,  0666, },
    { "npc", &spufs_npc_ops, 0666, },
    { "psmap", &spufs_psmap_fops, 0666, SPUFS_PS_MAP_SIZE, },
    { "phys-id", &spufs_id_ops, 0666, },
    { "object-id", &spufs_object_id_ops, 0666, },
    { "tid", &spufs_tid_fops, 0444, },
    { "stat", &spufs_stat_fops, 0444, },
    {},
};

const struct spufs_tree_descr spufs_dir_debug_contents[] = {
    { ".ctx", &spufs_ctx_fops, 0444, },
    {},
};

const struct spufs_coredump_reader spufs_coredump_read[] = {
    { "regs", __spufs_regs_read, NULL, sizeof(struct spu_reg128[128])},
    { "fpcr", __spufs_fpcr_read, NULL, sizeof(struct spu_reg128) },
    { "lslr", NULL, spufs_lslr_get, 19 },
    { "decr", NULL, spufs_decr_get, 19 },
    { "decr_status", NULL, spufs_decr_status_get, 19 },
    { "mem", __spufs_mem_read, NULL, LS_SIZE, },
    { "signal1", __spufs_signal1_read, NULL, sizeof(u32) },
    { "signal1_type", NULL, spufs_signal1_type_get, 19 },
    { "signal2", __spufs_signal2_read, NULL, sizeof(u32) },
    { "signal2_type", NULL, spufs_signal2_type_get, 19 },
    { "event_mask", NULL, spufs_event_mask_get, 19 },
    { "event_status", NULL, spufs_event_status_get, 19 },
    { "mbox_info", __spufs_mbox_info_read, NULL, sizeof(u32) },
    { "ibox_info", __spufs_ibox_info_read, NULL, sizeof(u32) },
    { "wbox_info", __spufs_wbox_info_read, NULL, 4 * sizeof(u32)},
    { "dma_info", __spufs_dma_info_read, NULL, sizeof(struct spu_dma_info)},
    { "proxydma_info", __spufs_proxydma_info_read,
               NULL, sizeof(struct spu_proxydma_info)},
    { "object-id", NULL, spufs_object_id_get, 19 },
    { "npc", NULL, spufs_npc_get, 19 },
    { NULL },
};