nvram_64.c

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/*
 *  c 2001 PPC 64 Team, IBM Corp
 *
 *      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 of the License, or (at your option) any later version.
 *
 * /dev/nvram driver for PPC64
 *
 * This perhaps should live in drivers/char
 *
 * TODO: Split the /dev/nvram part (that one can use
 *       drivers/char/generic_nvram.c) from the arch & partition
 *       parsing code.
 */

#include <linux/module.h>

#include <linux/types.h>
#include <linux/errno.h>
#include <linux/fs.h>
#include <linux/miscdevice.h>
#include <linux/fcntl.h>
#include <linux/nvram.h>
#include <linux/init.h>
#include <linux/slab.h>
#include <linux/spinlock.h>
#include <asm/uaccess.h>
#include <asm/nvram.h>
#include <asm/rtas.h>
#include <asm/prom.h>
#include <asm/machdep.h>

#undef DEBUG_NVRAM

#define NVRAM_HEADER_LEN    sizeof(struct nvram_header)
#define NVRAM_BLOCK_LEN     NVRAM_HEADER_LEN

/* If change this size, then change the size of NVNAME_LEN */
struct nvram_header {
    unsigned char signature;
    unsigned char checksum;
    unsigned short length;
    /* Terminating null required only for names < 12 chars. */
    char name[12];
};

struct nvram_partition {
    struct list_head partition;
    struct nvram_header header;
    unsigned int index;
};

static LIST_HEAD(nvram_partitions);

static loff_t dev_nvram_llseek(struct file *file, loff_t offset, int origin)
{
    int size;

    if (ppc_md.nvram_size == NULL)
        return -ENODEV;
    size = ppc_md.nvram_size();

    switch (origin) {
    case 1:
        offset += file->f_pos;
        break;
    case 2:
        offset += size;
        break;
    }
    if (offset < 0)
        return -EINVAL;
    file->f_pos = offset;
    return file->f_pos;
}


static ssize_t dev_nvram_read(struct file *file, char __user *buf,
              size_t count, loff_t *ppos)
{
    ssize_t ret;
    char *tmp = NULL;
    ssize_t size;

    ret = -ENODEV;
    if (!ppc_md.nvram_size)
        goto out;

    ret = 0;
    size = ppc_md.nvram_size();
    if (*ppos >= size || size < 0)
        goto out;

    count = min_t(size_t, count, size - *ppos);
    count = min(count, PAGE_SIZE);

    ret = -ENOMEM;
    tmp = kmalloc(count, GFP_KERNEL);
    if (!tmp)
        goto out;

    ret = ppc_md.nvram_read(tmp, count, ppos);
    if (ret <= 0)
        goto out;

    if (copy_to_user(buf, tmp, ret))
        ret = -EFAULT;

out:
    kfree(tmp);
    return ret;

}

static ssize_t dev_nvram_write(struct file *file, const char __user *buf,
              size_t count, loff_t *ppos)
{
    ssize_t ret;
    char *tmp = NULL;
    ssize_t size;

    ret = -ENODEV;
    if (!ppc_md.nvram_size)
        goto out;

    ret = 0;
    size = ppc_md.nvram_size();
    if (*ppos >= size || size < 0)
        goto out;

    count = min_t(size_t, count, size - *ppos);
    count = min(count, PAGE_SIZE);

    ret = -ENOMEM;
    tmp = kmalloc(count, GFP_KERNEL);
    if (!tmp)
        goto out;

    ret = -EFAULT;
    if (copy_from_user(tmp, buf, count))
        goto out;

    ret = ppc_md.nvram_write(tmp, count, ppos);

out:
    kfree(tmp);
    return ret;

}

static long dev_nvram_ioctl(struct file *file, unsigned int cmd,
                unsigned long arg)
{
    switch(cmd) {
#ifdef CONFIG_PPC_PMAC
    case OBSOLETE_PMAC_NVRAM_GET_OFFSET:
        printk(KERN_WARNING "nvram: Using obsolete PMAC_NVRAM_GET_OFFSET ioctl\n");
    case IOC_NVRAM_GET_OFFSET: {
        int part, offset;

        if (!machine_is(powermac))
            return -EINVAL;
        if (copy_from_user(&part, (void __user*)arg, sizeof(part)) != 0)
            return -EFAULT;
        if (part < pmac_nvram_OF || part > pmac_nvram_NR)
            return -EINVAL;
        offset = pmac_get_partition(part);
        if (offset < 0)
            return offset;
        if (copy_to_user((void __user*)arg, &offset, sizeof(offset)) != 0)
            return -EFAULT;
        return 0;
    }
#endif /* CONFIG_PPC_PMAC */
    default:
        return -EINVAL;
    }
}

const struct file_operations nvram_fops = {
    .owner      = THIS_MODULE,
    .llseek     = dev_nvram_llseek,
    .read       = dev_nvram_read,
    .write      = dev_nvram_write,
    .unlocked_ioctl = dev_nvram_ioctl,
};

static struct miscdevice nvram_dev = {
    NVRAM_MINOR,
    "nvram",
    &nvram_fops
};


#ifdef DEBUG_NVRAM
static void __init nvram_print_partitions(char * label)
{
    struct nvram_partition * tmp_part;
    
    printk(KERN_WARNING "--------%s---------\n", label);
    printk(KERN_WARNING "indx\t\tsig\tchks\tlen\tname\n");
    list_for_each_entry(tmp_part, &nvram_partitions, partition) {
        printk(KERN_WARNING "%4d    \t%02x\t%02x\t%d\t%12s\n",
               tmp_part->index, tmp_part->header.signature,
               tmp_part->header.checksum, tmp_part->header.length,
               tmp_part->header.name);
    }
}
#endif


static int __init nvram_write_header(struct nvram_partition * part)
{
    loff_t tmp_index;
    int rc;
    
    tmp_index = part->index;
    rc = ppc_md.nvram_write((char *)&part->header, NVRAM_HEADER_LEN, &tmp_index); 

    return rc;
}


static unsigned char __init nvram_checksum(struct nvram_header *p)
{
    unsigned int c_sum, c_sum2;
    unsigned short *sp = (unsigned short *)p->name; /* assume 6 shorts */
    c_sum = p->signature + p->length + sp[0] + sp[1] + sp[2] + sp[3] + sp[4] + sp[5];

    /* The sum may have spilled into the 3rd byte.  Fold it back. */
    c_sum = ((c_sum & 0xffff) + (c_sum >> 16)) & 0xffff;
    /* The sum cannot exceed 2 bytes.  Fold it into a checksum */
    c_sum2 = (c_sum >> 8) + (c_sum << 8);
    c_sum = ((c_sum + c_sum2) >> 8) & 0xff;
    return c_sum;
}

/*
 * Per the criteria passed via nvram_remove_partition(), should this
 * partition be removed?  1=remove, 0=keep
 */
static int nvram_can_remove_partition(struct nvram_partition *part,
        const char *name, int sig, const char *exceptions[])
{
    if (part->header.signature != sig)
        return 0;
    if (name) {
        if (strncmp(name, part->header.name, 12))
            return 0;
    } else if (exceptions) {
        const char **except;
        for (except = exceptions; *except; except++) {
            if (!strncmp(*except, part->header.name, 12))
                return 0;
        }
    }
    return 1;
}

int __init nvram_remove_partition(const char *name, int sig,
                        const char *exceptions[])
{
    struct nvram_partition *part, *prev, *tmp;
    int rc;

    list_for_each_entry(part, &nvram_partitions, partition) {
        if (!nvram_can_remove_partition(part, name, sig, exceptions))
            continue;

        /* Make partition a free partition */
        part->header.signature = NVRAM_SIG_FREE;
        strncpy(part->header.name, "wwwwwwwwwwww", 12);
        part->header.checksum = nvram_checksum(&part->header);
        rc = nvram_write_header(part);
        if (rc <= 0) {
            printk(KERN_ERR "nvram_remove_partition: nvram_write failed (%d)\n", rc);
            return rc;
        }
    }

    /* Merge contiguous ones */
    prev = NULL;
    list_for_each_entry_safe(part, tmp, &nvram_partitions, partition) {
        if (part->header.signature != NVRAM_SIG_FREE) {
            prev = NULL;
            continue;
        }
        if (prev) {
            prev->header.length += part->header.length;
            prev->header.checksum = nvram_checksum(&part->header);
            rc = nvram_write_header(part);
            if (rc <= 0) {
                printk(KERN_ERR "nvram_remove_partition: nvram_write failed (%d)\n", rc);
                return rc;
            }
            list_del(&part->partition);
            kfree(part);
        } else
            prev = part;
    }
    
    return 0;
}

loff_t __init nvram_create_partition(const char *name, int sig,
                     int req_size, int min_size)
{
    struct nvram_partition *part;
    struct nvram_partition *new_part;
    struct nvram_partition *free_part = NULL;
    static char nv_init_vals[16];
    loff_t tmp_index;
    long size = 0;
    int rc;

    /* Convert sizes from bytes to blocks */
    req_size = _ALIGN_UP(req_size, NVRAM_BLOCK_LEN) / NVRAM_BLOCK_LEN;
    min_size = _ALIGN_UP(min_size, NVRAM_BLOCK_LEN) / NVRAM_BLOCK_LEN;

    /* If no minimum size specified, make it the same as the
     * requested size
     */
    if (min_size == 0)
        min_size = req_size;
    if (min_size > req_size)
        return -EINVAL;

    /* Now add one block to each for the header */
    req_size += 1;
    min_size += 1;

    /* Find a free partition that will give us the maximum needed size 
       If can't find one that will give us the minimum size needed */
    list_for_each_entry(part, &nvram_partitions, partition) {
        if (part->header.signature != NVRAM_SIG_FREE)
            continue;

        if (part->header.length >= req_size) {
            size = req_size;
            free_part = part;
            break;
        }
        if (part->header.length > size &&
            part->header.length >= min_size) {
            size = part->header.length;
            free_part = part;
        }
    }
    if (!size)
        return -ENOSPC;
    
    /* Create our OS partition */
    new_part = kmalloc(sizeof(*new_part), GFP_KERNEL);
    if (!new_part) {
        pr_err("nvram_create_os_partition: kmalloc failed\n");
        return -ENOMEM;
    }

    new_part->index = free_part->index;
    new_part->header.signature = sig;
    new_part->header.length = size;
    strncpy(new_part->header.name, name, 12);
    new_part->header.checksum = nvram_checksum(&new_part->header);

    rc = nvram_write_header(new_part);
    if (rc <= 0) {
        pr_err("nvram_create_os_partition: nvram_write_header "
               "failed (%d)\n", rc);
        return rc;
    }
    list_add_tail(&new_part->partition, &free_part->partition);

    /* Adjust or remove the partition we stole the space from */
    if (free_part->header.length > size) {
        free_part->index += size * NVRAM_BLOCK_LEN;
        free_part->header.length -= size;
        free_part->header.checksum = nvram_checksum(&free_part->header);
        rc = nvram_write_header(free_part);
        if (rc <= 0) {
            pr_err("nvram_create_os_partition: nvram_write_header "
                   "failed (%d)\n", rc);
            return rc;
        }
    } else {
        list_del(&free_part->partition);
        kfree(free_part);
    } 

    /* Clear the new partition */
    for (tmp_index = new_part->index + NVRAM_HEADER_LEN;
         tmp_index <  ((size - 1) * NVRAM_BLOCK_LEN);
         tmp_index += NVRAM_BLOCK_LEN) {
        rc = ppc_md.nvram_write(nv_init_vals, NVRAM_BLOCK_LEN, &tmp_index);
        if (rc <= 0) {
            pr_err("nvram_create_partition: nvram_write failed (%d)\n", rc);
            return rc;
        }
    }
    
    return new_part->index + NVRAM_HEADER_LEN;
}

int nvram_get_partition_size(loff_t data_index)
{
    struct nvram_partition *part;
    
    list_for_each_entry(part, &nvram_partitions, partition) {
        if (part->index + NVRAM_HEADER_LEN == data_index)
            return (part->header.length - 1) * NVRAM_BLOCK_LEN;
    }
    return -1;
}


loff_t nvram_find_partition(const char *name, int sig, int *out_size)
{
    struct nvram_partition *p;

    list_for_each_entry(p, &nvram_partitions, partition) {
        if (p->header.signature == sig &&
            (!name || !strncmp(p->header.name, name, 12))) {
            if (out_size)
                *out_size = (p->header.length - 1) *
                    NVRAM_BLOCK_LEN;
            return p->index + NVRAM_HEADER_LEN;
        }
    }
    return 0;
}

int __init nvram_scan_partitions(void)
{
    loff_t cur_index = 0;
    struct nvram_header phead;
    struct nvram_partition * tmp_part;
    unsigned char c_sum;
    char * header;
    int total_size;
    int err;

    if (ppc_md.nvram_size == NULL || ppc_md.nvram_size() <= 0)
        return -ENODEV;
    total_size = ppc_md.nvram_size();
    
    header = kmalloc(NVRAM_HEADER_LEN, GFP_KERNEL);
    if (!header) {
        printk(KERN_ERR "nvram_scan_partitions: Failed kmalloc\n");
        return -ENOMEM;
    }

    while (cur_index < total_size) {

        err = ppc_md.nvram_read(header, NVRAM_HEADER_LEN, &cur_index);
        if (err != NVRAM_HEADER_LEN) {
            printk(KERN_ERR "nvram_scan_partitions: Error parsing "
                   "nvram partitions\n");
            goto out;
        }

        cur_index -= NVRAM_HEADER_LEN; /* nvram_read will advance us */

        memcpy(&phead, header, NVRAM_HEADER_LEN);

        err = 0;
        c_sum = nvram_checksum(&phead);
        if (c_sum != phead.checksum) {
            printk(KERN_WARNING "WARNING: nvram partition checksum"
                   " was %02x, should be %02x!\n",
                   phead.checksum, c_sum);
            printk(KERN_WARNING "Terminating nvram partition scan\n");
            goto out;
        }
        if (!phead.length) {
            printk(KERN_WARNING "WARNING: nvram corruption "
                   "detected: 0-length partition\n");
            goto out;
        }
        tmp_part = (struct nvram_partition *)
            kmalloc(sizeof(struct nvram_partition), GFP_KERNEL);
        err = -ENOMEM;
        if (!tmp_part) {
            printk(KERN_ERR "nvram_scan_partitions: kmalloc failed\n");
            goto out;
        }
        
        memcpy(&tmp_part->header, &phead, NVRAM_HEADER_LEN);
        tmp_part->index = cur_index;
        list_add_tail(&tmp_part->partition, &nvram_partitions);
        
        cur_index += phead.length * NVRAM_BLOCK_LEN;
    }
    err = 0;

#ifdef DEBUG_NVRAM
    nvram_print_partitions("NVRAM Partitions");
#endif

 out:
    kfree(header);
    return err;
}

static int __init nvram_init(void)
{
    int rc;
    
    BUILD_BUG_ON(NVRAM_BLOCK_LEN != 16);

    if (ppc_md.nvram_size == NULL || ppc_md.nvram_size() <= 0)
        return  -ENODEV;

    rc = misc_register(&nvram_dev);
    if (rc != 0) {
        printk(KERN_ERR "nvram_init: failed to register device\n");
        return rc;
    }
    
    return rc;
}

void __exit nvram_cleanup(void)
{
        misc_deregister( &nvram_dev );
}

module_init(nvram_init);
module_exit(nvram_cleanup);
MODULE_LICENSE("GPL");