pci-dma.c

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/*
** PARISC 1.1 Dynamic DMA mapping support.
** This implementation is for PA-RISC platforms that do not support
** I/O TLBs (aka DMA address translation hardware).
** See Documentation/DMA-API-HOWTO.txt for interface definitions.
**
**      (c) Copyright 1999,2000 Hewlett-Packard Company
**      (c) Copyright 2000 Grant Grundler
**  (c) Copyright 2000 Philipp Rumpf <[email protected]>
**      (c) Copyright 2000 John Marvin
**
** "leveraged" from 2.3.47: arch/ia64/kernel/pci-dma.c.
** (I assume it's from David Mosberger-Tang but there was no Copyright)
**
** AFAIK, all PA7100LC and PA7300LC platforms can use this code.
**
** - ggg
*/

#include <linux/init.h>
#include <linux/gfp.h>
#include <linux/mm.h>
#include <linux/pci.h>
#include <linux/proc_fs.h>
#include <linux/seq_file.h>
#include <linux/string.h>
#include <linux/types.h>
#include <linux/scatterlist.h>
#include <linux/export.h>

#include <asm/cacheflush.h>
#include <asm/dma.h>    /* for DMA_CHUNK_SIZE */
#include <asm/io.h>
#include <asm/page.h>   /* get_order */
#include <asm/pgalloc.h>
#include <asm/uaccess.h>
#include <asm/tlbflush.h>   /* for purge_tlb_*() macros */

static struct proc_dir_entry * proc_gsc_root __read_mostly = NULL;
static unsigned long pcxl_used_bytes __read_mostly = 0;
static unsigned long pcxl_used_pages __read_mostly = 0;

extern unsigned long pcxl_dma_start; /* Start of pcxl dma mapping area */
static spinlock_t   pcxl_res_lock;
static char    *pcxl_res_map;
static int     pcxl_res_hint;
static int     pcxl_res_size;

#ifdef DEBUG_PCXL_RESOURCE
#define DBG_RES(x...)   printk(x)
#else
#define DBG_RES(x...)
#endif


/*
** Dump a hex representation of the resource map.
*/

#ifdef DUMP_RESMAP
static
void dump_resmap(void)
{
    u_long *res_ptr = (unsigned long *)pcxl_res_map;
    u_long i = 0;

    printk("res_map: ");
    for(; i < (pcxl_res_size / sizeof(unsigned long)); ++i, ++res_ptr)
        printk("%08lx ", *res_ptr);

    printk("\n");
}
#else
static inline void dump_resmap(void) {;}
#endif

static int pa11_dma_supported( struct device *dev, u64 mask)
{
    return 1;
}

static inline int map_pte_uncached(pte_t * pte,
        unsigned long vaddr,
        unsigned long size, unsigned long *paddr_ptr)
{
    unsigned long end;
    unsigned long orig_vaddr = vaddr;

    vaddr &= ~PMD_MASK;
    end = vaddr + size;
    if (end > PMD_SIZE)
        end = PMD_SIZE;
    do {
        unsigned long flags;

        if (!pte_none(*pte))
            printk(KERN_ERR "map_pte_uncached: page already exists\n");
        set_pte(pte, __mk_pte(*paddr_ptr, PAGE_KERNEL_UNC));
        purge_tlb_start(flags);
        pdtlb_kernel(orig_vaddr);
        purge_tlb_end(flags);
        vaddr += PAGE_SIZE;
        orig_vaddr += PAGE_SIZE;
        (*paddr_ptr) += PAGE_SIZE;
        pte++;
    } while (vaddr < end);
    return 0;
}

static inline int map_pmd_uncached(pmd_t * pmd, unsigned long vaddr,
        unsigned long size, unsigned long *paddr_ptr)
{
    unsigned long end;
    unsigned long orig_vaddr = vaddr;

    vaddr &= ~PGDIR_MASK;
    end = vaddr + size;
    if (end > PGDIR_SIZE)
        end = PGDIR_SIZE;
    do {
        pte_t * pte = pte_alloc_kernel(pmd, vaddr);
        if (!pte)
            return -ENOMEM;
        if (map_pte_uncached(pte, orig_vaddr, end - vaddr, paddr_ptr))
            return -ENOMEM;
        vaddr = (vaddr + PMD_SIZE) & PMD_MASK;
        orig_vaddr += PMD_SIZE;
        pmd++;
    } while (vaddr < end);
    return 0;
}

static inline int map_uncached_pages(unsigned long vaddr, unsigned long size,
        unsigned long paddr)
{
    pgd_t * dir;
    unsigned long end = vaddr + size;

    dir = pgd_offset_k(vaddr);
    do {
        pmd_t *pmd;
        
        pmd = pmd_alloc(NULL, dir, vaddr);
        if (!pmd)
            return -ENOMEM;
        if (map_pmd_uncached(pmd, vaddr, end - vaddr, &paddr))
            return -ENOMEM;
        vaddr = vaddr + PGDIR_SIZE;
        dir++;
    } while (vaddr && (vaddr < end));
    return 0;
}

static inline void unmap_uncached_pte(pmd_t * pmd, unsigned long vaddr,
        unsigned long size)
{
    pte_t * pte;
    unsigned long end;
    unsigned long orig_vaddr = vaddr;

    if (pmd_none(*pmd))
        return;
    if (pmd_bad(*pmd)) {
        pmd_ERROR(*pmd);
        pmd_clear(pmd);
        return;
    }
    pte = pte_offset_map(pmd, vaddr);
    vaddr &= ~PMD_MASK;
    end = vaddr + size;
    if (end > PMD_SIZE)
        end = PMD_SIZE;
    do {
        unsigned long flags;
        pte_t page = *pte;

        pte_clear(&init_mm, vaddr, pte);
        purge_tlb_start(flags);
        pdtlb_kernel(orig_vaddr);
        purge_tlb_end(flags);
        vaddr += PAGE_SIZE;
        orig_vaddr += PAGE_SIZE;
        pte++;
        if (pte_none(page) || pte_present(page))
            continue;
        printk(KERN_CRIT "Whee.. Swapped out page in kernel page table\n");
    } while (vaddr < end);
}

static inline void unmap_uncached_pmd(pgd_t * dir, unsigned long vaddr,
        unsigned long size)
{
    pmd_t * pmd;
    unsigned long end;
    unsigned long orig_vaddr = vaddr;

    if (pgd_none(*dir))
        return;
    if (pgd_bad(*dir)) {
        pgd_ERROR(*dir);
        pgd_clear(dir);
        return;
    }
    pmd = pmd_offset(dir, vaddr);
    vaddr &= ~PGDIR_MASK;
    end = vaddr + size;
    if (end > PGDIR_SIZE)
        end = PGDIR_SIZE;
    do {
        unmap_uncached_pte(pmd, orig_vaddr, end - vaddr);
        vaddr = (vaddr + PMD_SIZE) & PMD_MASK;
        orig_vaddr += PMD_SIZE;
        pmd++;
    } while (vaddr < end);
}

static void unmap_uncached_pages(unsigned long vaddr, unsigned long size)
{
    pgd_t * dir;
    unsigned long end = vaddr + size;

    dir = pgd_offset_k(vaddr);
    do {
        unmap_uncached_pmd(dir, vaddr, end - vaddr);
        vaddr = vaddr + PGDIR_SIZE;
        dir++;
    } while (vaddr && (vaddr < end));
}

#define PCXL_SEARCH_LOOP(idx, mask, size)  \
       for(; res_ptr < res_end; ++res_ptr) \
       { \
               if(0 == ((*res_ptr) & mask)) { \
                       *res_ptr |= mask; \
               idx = (int)((u_long)res_ptr - (u_long)pcxl_res_map); \
               pcxl_res_hint = idx + (size >> 3); \
                       goto resource_found; \
               } \
       }

#define PCXL_FIND_FREE_MAPPING(idx, mask, size)  { \
       u##size *res_ptr = (u##size *)&(pcxl_res_map[pcxl_res_hint & ~((size >> 3) - 1)]); \
       u##size *res_end = (u##size *)&pcxl_res_map[pcxl_res_size]; \
       PCXL_SEARCH_LOOP(idx, mask, size); \
       res_ptr = (u##size *)&pcxl_res_map[0]; \
       PCXL_SEARCH_LOOP(idx, mask, size); \
}

unsigned long
pcxl_alloc_range(size_t size)
{
    int res_idx;
    u_long mask, flags;
    unsigned int pages_needed = size >> PAGE_SHIFT;

    mask = (u_long) -1L;
    mask >>= BITS_PER_LONG - pages_needed;

    DBG_RES("pcxl_alloc_range() size: %d pages_needed %d pages_mask 0x%08lx\n", 
        size, pages_needed, mask);

    spin_lock_irqsave(&pcxl_res_lock, flags);

    if(pages_needed <= 8) {
        PCXL_FIND_FREE_MAPPING(res_idx, mask, 8);
    } else if(pages_needed <= 16) {
        PCXL_FIND_FREE_MAPPING(res_idx, mask, 16);
    } else if(pages_needed <= 32) {
        PCXL_FIND_FREE_MAPPING(res_idx, mask, 32);
    } else {
        panic("%s: pcxl_alloc_range() Too many pages to map.\n",
              __FILE__);
    }

    dump_resmap();
    panic("%s: pcxl_alloc_range() out of dma mapping resources\n",
          __FILE__);
    
resource_found:
    
    DBG_RES("pcxl_alloc_range() res_idx %d mask 0x%08lx res_hint: %d\n",
        res_idx, mask, pcxl_res_hint);

    pcxl_used_pages += pages_needed;
    pcxl_used_bytes += ((pages_needed >> 3) ? (pages_needed >> 3) : 1);

    spin_unlock_irqrestore(&pcxl_res_lock, flags);

    dump_resmap();

    /* 
    ** return the corresponding vaddr in the pcxl dma map
    */
    return (pcxl_dma_start + (res_idx << (PAGE_SHIFT + 3)));
}

#define PCXL_FREE_MAPPINGS(idx, m, size) \
        u##size *res_ptr = (u##size *)&(pcxl_res_map[(idx) + (((size >> 3) - 1) & (~((size >> 3) - 1)))]); \
        /* BUG_ON((*res_ptr & m) != m); */ \
        *res_ptr &= ~m;

/*
** clear bits in the pcxl resource map
*/
static void
pcxl_free_range(unsigned long vaddr, size_t size)
{
    u_long mask, flags;
    unsigned int res_idx = (vaddr - pcxl_dma_start) >> (PAGE_SHIFT + 3);
    unsigned int pages_mapped = size >> PAGE_SHIFT;

    mask = (u_long) -1L;
    mask >>= BITS_PER_LONG - pages_mapped;

    DBG_RES("pcxl_free_range() res_idx: %d size: %d pages_mapped %d mask 0x%08lx\n", 
        res_idx, size, pages_mapped, mask);

    spin_lock_irqsave(&pcxl_res_lock, flags);

    if(pages_mapped <= 8) {
        PCXL_FREE_MAPPINGS(res_idx, mask, 8);
    } else if(pages_mapped <= 16) {
        PCXL_FREE_MAPPINGS(res_idx, mask, 16);
    } else if(pages_mapped <= 32) {
        PCXL_FREE_MAPPINGS(res_idx, mask, 32);
    } else {
        panic("%s: pcxl_free_range() Too many pages to unmap.\n",
              __FILE__);
    }
    
    pcxl_used_pages -= (pages_mapped ? pages_mapped : 1);
    pcxl_used_bytes -= ((pages_mapped >> 3) ? (pages_mapped >> 3) : 1);

    spin_unlock_irqrestore(&pcxl_res_lock, flags);

    dump_resmap();
}

static int proc_pcxl_dma_show(struct seq_file *m, void *v)
{
#if 0
    u_long i = 0;
    unsigned long *res_ptr = (u_long *)pcxl_res_map;
#endif
    unsigned long total_pages = pcxl_res_size << 3;   /* 8 bits per byte */

    seq_printf(m, "\nDMA Mapping Area size    : %d bytes (%ld pages)\n",
        PCXL_DMA_MAP_SIZE, total_pages);

    seq_printf(m, "Resource bitmap : %d bytes\n", pcxl_res_size);

    seq_puts(m,  "        total:    free:    used:   % used:\n");
    seq_printf(m, "blocks  %8d %8ld %8ld %8ld%%\n", pcxl_res_size,
        pcxl_res_size - pcxl_used_bytes, pcxl_used_bytes,
        (pcxl_used_bytes * 100) / pcxl_res_size);

    seq_printf(m, "pages   %8ld %8ld %8ld %8ld%%\n", total_pages,
        total_pages - pcxl_used_pages, pcxl_used_pages,
        (pcxl_used_pages * 100 / total_pages));

#if 0
    seq_puts(m, "\nResource bitmap:");

    for(; i < (pcxl_res_size / sizeof(u_long)); ++i, ++res_ptr) {
        if ((i & 7) == 0)
            seq_puts(m,"\n   ");
        seq_printf(m, "%s %08lx", buf, *res_ptr);
    }
#endif
    seq_putc(m, '\n');
    return 0;
}

static int proc_pcxl_dma_open(struct inode *inode, struct file *file)
{
    return single_open(file, proc_pcxl_dma_show, NULL);
}

static const struct file_operations proc_pcxl_dma_ops = {
    .owner      = THIS_MODULE,
    .open       = proc_pcxl_dma_open,
    .read       = seq_read,
    .llseek     = seq_lseek,
    .release    = single_release,
};

static int __init
pcxl_dma_init(void)
{
    if (pcxl_dma_start == 0)
        return 0;

    spin_lock_init(&pcxl_res_lock);
    pcxl_res_size = PCXL_DMA_MAP_SIZE >> (PAGE_SHIFT + 3);
    pcxl_res_hint = 0;
    pcxl_res_map = (char *)__get_free_pages(GFP_KERNEL,
                        get_order(pcxl_res_size));
    memset(pcxl_res_map, 0, pcxl_res_size);
    proc_gsc_root = proc_mkdir("gsc", NULL);
    if (!proc_gsc_root)
            printk(KERN_WARNING
            "pcxl_dma_init: Unable to create gsc /proc dir entry\n");
    else {
        struct proc_dir_entry* ent;
        ent = proc_create("pcxl_dma", 0, proc_gsc_root,
                  &proc_pcxl_dma_ops);
        if (!ent)
            printk(KERN_WARNING
                "pci-dma.c: Unable to create pcxl_dma /proc entry.\n");
    }
    return 0;
}

__initcall(pcxl_dma_init);

static void * pa11_dma_alloc_consistent (struct device *dev, size_t size, dma_addr_t *dma_handle, gfp_t flag)
{
    unsigned long vaddr;
    unsigned long paddr;
    int order;

    order = get_order(size);
    size = 1 << (order + PAGE_SHIFT);
    vaddr = pcxl_alloc_range(size);
    paddr = __get_free_pages(flag, order);
    flush_kernel_dcache_range(paddr, size);
    paddr = __pa(paddr);
    map_uncached_pages(vaddr, size, paddr);
    *dma_handle = (dma_addr_t) paddr;

#if 0
/* This probably isn't needed to support EISA cards.
** ISA cards will certainly only support 24-bit DMA addressing.
** Not clear if we can, want, or need to support ISA.
*/
    if (!dev || *dev->coherent_dma_mask < 0xffffffff)
        gfp |= GFP_DMA;
#endif
    return (void *)vaddr;
}

static void pa11_dma_free_consistent (struct device *dev, size_t size, void *vaddr, dma_addr_t dma_handle)
{
    int order;

    order = get_order(size);
    size = 1 << (order + PAGE_SHIFT);
    unmap_uncached_pages((unsigned long)vaddr, size);
    pcxl_free_range((unsigned long)vaddr, size);
    free_pages((unsigned long)__va(dma_handle), order);
}

static dma_addr_t pa11_dma_map_single(struct device *dev, void *addr, size_t size, enum dma_data_direction direction)
{
    BUG_ON(direction == DMA_NONE);

    flush_kernel_dcache_range((unsigned long) addr, size);
    return virt_to_phys(addr);
}

static void pa11_dma_unmap_single(struct device *dev, dma_addr_t dma_handle, size_t size, enum dma_data_direction direction)
{
    BUG_ON(direction == DMA_NONE);

    if (direction == DMA_TO_DEVICE)
        return;

    /*
     * For PCI_DMA_FROMDEVICE this flush is not necessary for the
     * simple map/unmap case. However, it IS necessary if if
     * pci_dma_sync_single_* has been called and the buffer reused.
     */

    flush_kernel_dcache_range((unsigned long) phys_to_virt(dma_handle), size);
    return;
}

static int pa11_dma_map_sg(struct device *dev, struct scatterlist *sglist, int nents, enum dma_data_direction direction)
{
    int i;

    BUG_ON(direction == DMA_NONE);

    for (i = 0; i < nents; i++, sglist++ ) {
        unsigned long vaddr = sg_virt_addr(sglist);
        sg_dma_address(sglist) = (dma_addr_t) virt_to_phys(vaddr);
        sg_dma_len(sglist) = sglist->length;
        flush_kernel_dcache_range(vaddr, sglist->length);
    }
    return nents;
}

static void pa11_dma_unmap_sg(struct device *dev, struct scatterlist *sglist, int nents, enum dma_data_direction direction)
{
    int i;

    BUG_ON(direction == DMA_NONE);

    if (direction == DMA_TO_DEVICE)
        return;

    /* once we do combining we'll need to use phys_to_virt(sg_dma_address(sglist)) */

    for (i = 0; i < nents; i++, sglist++ )
        flush_kernel_dcache_range(sg_virt_addr(sglist), sglist->length);
    return;
}

static void pa11_dma_sync_single_for_cpu(struct device *dev, dma_addr_t dma_handle, unsigned long offset, size_t size, enum dma_data_direction direction)
{
    BUG_ON(direction == DMA_NONE);

    flush_kernel_dcache_range((unsigned long) phys_to_virt(dma_handle) + offset, size);
}

static void pa11_dma_sync_single_for_device(struct device *dev, dma_addr_t dma_handle, unsigned long offset, size_t size, enum dma_data_direction direction)
{
    BUG_ON(direction == DMA_NONE);

    flush_kernel_dcache_range((unsigned long) phys_to_virt(dma_handle) + offset, size);
}

static void pa11_dma_sync_sg_for_cpu(struct device *dev, struct scatterlist *sglist, int nents, enum dma_data_direction direction)
{
    int i;

    /* once we do combining we'll need to use phys_to_virt(sg_dma_address(sglist)) */

    for (i = 0; i < nents; i++, sglist++ )
        flush_kernel_dcache_range(sg_virt_addr(sglist), sglist->length);
}

static void pa11_dma_sync_sg_for_device(struct device *dev, struct scatterlist *sglist, int nents, enum dma_data_direction direction)
{
    int i;

    /* once we do combining we'll need to use phys_to_virt(sg_dma_address(sglist)) */

    for (i = 0; i < nents; i++, sglist++ )
        flush_kernel_dcache_range(sg_virt_addr(sglist), sglist->length);
}

struct hppa_dma_ops pcxl_dma_ops = {
    .dma_supported =    pa11_dma_supported,
    .alloc_consistent = pa11_dma_alloc_consistent,
    .alloc_noncoherent =    pa11_dma_alloc_consistent,
    .free_consistent =  pa11_dma_free_consistent,
    .map_single =       pa11_dma_map_single,
    .unmap_single =     pa11_dma_unmap_single,
    .map_sg =       pa11_dma_map_sg,
    .unmap_sg =     pa11_dma_unmap_sg,
    .dma_sync_single_for_cpu = pa11_dma_sync_single_for_cpu,
    .dma_sync_single_for_device = pa11_dma_sync_single_for_device,
    .dma_sync_sg_for_cpu = pa11_dma_sync_sg_for_cpu,
    .dma_sync_sg_for_device = pa11_dma_sync_sg_for_device,
};

static void *fail_alloc_consistent(struct device *dev, size_t size,
                   dma_addr_t *dma_handle, gfp_t flag)
{
    return NULL;
}

static void *pa11_dma_alloc_noncoherent(struct device *dev, size_t size,
                      dma_addr_t *dma_handle, gfp_t flag)
{
    void *addr;

    addr = (void *)__get_free_pages(flag, get_order(size));
    if (addr)
        *dma_handle = (dma_addr_t)virt_to_phys(addr);

    return addr;
}

static void pa11_dma_free_noncoherent(struct device *dev, size_t size,
                    void *vaddr, dma_addr_t iova)
{
    free_pages((unsigned long)vaddr, get_order(size));
    return;
}

struct hppa_dma_ops pcx_dma_ops = {
    .dma_supported =    pa11_dma_supported,
    .alloc_consistent = fail_alloc_consistent,
    .alloc_noncoherent =    pa11_dma_alloc_noncoherent,
    .free_consistent =  pa11_dma_free_noncoherent,
    .map_single =       pa11_dma_map_single,
    .unmap_single =     pa11_dma_unmap_single,
    .map_sg =       pa11_dma_map_sg,
    .unmap_sg =     pa11_dma_unmap_sg,
    .dma_sync_single_for_cpu =  pa11_dma_sync_single_for_cpu,
    .dma_sync_single_for_device =   pa11_dma_sync_single_for_device,
    .dma_sync_sg_for_cpu =      pa11_dma_sync_sg_for_cpu,
    .dma_sync_sg_for_device =   pa11_dma_sync_sg_for_device,
};