nvram_64.c

linux-2.6.15.6

/*
 *  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

static int nvram_scan_partitions(void);
static int nvram_setup_partition(void);
static int nvram_create_os_partition(void);
static int nvram_remove_os_partition(void);

static struct nvram_partition * nvram_part;
static long nvram_error_log_index = -1;
static long nvram_error_log_size = 0;

int no_logging = 1; 	/* Until we initialize everything,
			 * make sure we don't try logging
			 * anything */

extern volatile int error_log_cnt;

struct err_log_info {
	int error_type;
	unsigned int seq_num;
};

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 len;
	char *tmp_buffer;
	int size;

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

	if (!access_ok(VERIFY_WRITE, buf, count))
		return -EFAULT;
	if (*ppos >= size)
		return 0;
	if (count > size) 
		count = size;

	tmp_buffer = (char *) kmalloc(count, GFP_KERNEL);
	if (!tmp_buffer) {
		printk(KERN_ERR "dev_read_nvram: kmalloc failed\n");
		return -ENOMEM;
	}

	len = ppc_md.nvram_read(tmp_buffer, count, ppos);
	if ((long)len <= 0) {
		kfree(tmp_buffer);
		return len;
	}

	if (copy_to_user(buf, tmp_buffer, len)) {
		kfree(tmp_buffer);
		return -EFAULT;
	}

	kfree(tmp_buffer);
	return len;

}

static ssize_t dev_nvram_write(struct file *file, const char __user *buf,
			   size_t count, loff_t *ppos)
{
	ssize_t len;
	char * tmp_buffer;
	int size;

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

	if (!access_ok(VERIFY_READ, buf, count))
		return -EFAULT;
	if (*ppos >= size)
		return 0;
	if (count > size)
		count = size;

	tmp_buffer = (char *) kmalloc(count, GFP_KERNEL);
	if (!tmp_buffer) {
		printk(KERN_ERR "dev_nvram_write: kmalloc failed\n");
		return -ENOMEM;
	}
	
	if (copy_from_user(tmp_buffer, buf, count)) {
		kfree(tmp_buffer);
		return -EFAULT;
	}

	len = ppc_md.nvram_write(tmp_buffer, count, ppos);
	if ((long)len <= 0) {
		kfree(tmp_buffer);
		return len;
	}

	kfree(tmp_buffer);
	return len;
}

static int dev_nvram_ioctl(struct inode *inode, 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 != PLATFORM_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 */
	}
	return -EINVAL;
}

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

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


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


static int 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 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;
}


/*
 * Find an nvram partition, sig can be 0 for any
 * partition or name can be NULL for any name, else
 * tries to match both
 */
struct nvram_partition *nvram_find_partition(int sig, const char *name)
{
	struct nvram_partition * part;
	struct list_head * p;

	list_for_each(p, &nvram_part->partition) {
		part = list_entry(p, struct nvram_partition, partition);

		if (sig && part->header.signature != sig)
			continue;
		if (name && 0 != strncmp(name, part->header.name, 12))
			continue;
		return part; 
	}
	return NULL;
}
EXPORT_SYMBOL(nvram_find_partition);


static int nvram_remove_os_partition(void)
{
	struct list_head *i;
	struct list_head *j;
	struct nvram_partition * part;
	struct nvram_partition * cur_part;
	int rc;

	list_for_each(i, &nvram_part->partition) {
		part = list_entry(i, struct nvram_partition, partition);
		if (part->header.signature != NVRAM_SIG_OS)
			continue;
		
		/* Make os partition a free partition */
		part->header.signature = NVRAM_SIG_FREE;
		sprintf(part->header.name, "wwwwwwwwwwww");
		part->header.checksum = nvram_checksum(&part->header);

		/* Merge contiguous free partitions backwards */
		list_for_each_prev(j, &part->partition) {
			cur_part = list_entry(j, struct nvram_partition, partition);
			if (cur_part == nvram_part || cur_part->header.signature != NVRAM_SIG_FREE) {
				break;
			}
			
			part->header.length += cur_part->header.length;
			part->header.checksum = nvram_checksum(&part->header);
			part->index = cur_part->index;

			list_del(&cur_part->partition);
			kfree(cur_part);
			j = &part->partition; /* fixup our loop */
		}
		
		/* Merge contiguous free partitions forwards */
		list_for_each(j, &part->partition) {
			cur_part = list_entry(j, struct nvram_partition, partition);
			if (cur_part == nvram_part || cur_part->header.signature != NVRAM_SIG_FREE) {
				break;
			}

			part->header.length += cur_part->header.length;
			part->header.checksum = nvram_checksum(&part->header);

			list_del(&cur_part->partition);
			kfree(cur_part);
			j = &part->partition; /* fixup our loop */
		}
		
		rc = nvram_write_header(part);
		if (rc <= 0) {
			printk(KERN_ERR "nvram_remove_os_partition: nvram_write failed (%d)\n", rc);
			return rc;
		}

	}
	
	return 0;
}

/* nvram_create_os_partition
 *
 * Create a OS linux partition to buffer error logs.
 * Will create a partition starting at the first free
 * space found if space has enough room.
 */
static int nvram_create_os_partition(void)
{
	struct nvram_partition *part;
	struct nvram_partition *new_part;
	struct nvram_partition *free_part = NULL;
	int seq_init[2] = { 0, 0 };
	loff_t tmp_index;
	long size = 0;
	int rc;
	
	/* 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_part->partition, partition) {
		if (part->header.signature != NVRAM_SIG_FREE)
			continue;

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