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Commit d331d830 authored by Martyn Welch's avatar Martyn Welch Committed by Benjamin Herrenschmidt
Browse files

powerpc/nvram: Enable use Generic NVRAM driver for different size chips 



Remove the reliance on a staticly defined NVRAM size, allowing
platforms to support NVRAMs with sizes differing from the standard.

A fall back value is provided for platforms not supporting this extension.

Signed-off-by: default avatarMartyn Welch <martyn.welch@gefanuc.com>
Signed-off-by: default avatarBenjamin Herrenschmidt <benh@kernel.crashing.org>
parent 1d6ed322

arch/powerpc/include/asm/nvram.h

+3 −0
Original line number Diff line number Diff line
@@ -107,6 +107,9 @@ extern void pmac_xpram_write(int xpaddr, u8 data); 
/* Synchronize NVRAM */

extern void	nvram_sync(void);



/* Determine NVRAM size */

extern ssize_t nvram_get_size(void);



/* Normal access to NVRAM */

extern unsigned char nvram_read_byte(int i);

extern void nvram_write_byte(unsigned char c, int i);

arch/powerpc/kernel/setup_32.c

+8 −0
Original line number Diff line number Diff line
@@ -210,6 +210,14 @@ void nvram_write_byte(unsigned char val, int addr) 
}

EXPORT_SYMBOL(nvram_write_byte);



ssize_t nvram_get_size(void)

{

	if (ppc_md.nvram_size)

		return ppc_md.nvram_size();

	return -1;

}

EXPORT_SYMBOL(nvram_get_size);



void nvram_sync(void)

{

	if (ppc_md.nvram_sync)

drivers/char/generic_nvram.c

+20 −7
Original line number Diff line number Diff line
@@ -2,7 +2,7 @@ 
 * Generic /dev/nvram driver for architectures providing some

 * "generic" hooks, that is :

 *

 * nvram_read_byte, nvram_write_byte, nvram_sync

 * nvram_read_byte, nvram_write_byte, nvram_sync, nvram_get_size

 *

 * Note that an additional hook is supported for PowerMac only

 * for getting the nvram "partition" informations
@@ -28,6 +28,8 @@ 


#define NVRAM_SIZE	8192



static ssize_t nvram_len;



static loff_t nvram_llseek(struct file *file, loff_t offset, int origin)

{

	lock_kernel();
@@ -36,7 +38,7 @@ static loff_t nvram_llseek(struct file *file, loff_t offset, int origin) 
		offset += file->f_pos;

		break;

	case 2:

		offset += NVRAM_SIZE;

		offset += nvram_len;

		break;

	}

	if (offset < 0) {
@@ -56,9 +58,9 @@ static ssize_t read_nvram(struct file *file, char __user *buf, 


	if (!access_ok(VERIFY_WRITE, buf, count))

		return -EFAULT;

	if (*ppos >= NVRAM_SIZE)

	if (*ppos >= nvram_len)

		return 0;

	for (i = *ppos; count > 0 && i < NVRAM_SIZE; ++i, ++p, --count)

	for (i = *ppos; count > 0 && i < nvram_len; ++i, ++p, --count)

		if (__put_user(nvram_read_byte(i), p))

			return -EFAULT;

	*ppos = i;
@@ -74,9 +76,9 @@ static ssize_t write_nvram(struct file *file, const char __user *buf, 


	if (!access_ok(VERIFY_READ, buf, count))

		return -EFAULT;

	if (*ppos >= NVRAM_SIZE)

	if (*ppos >= nvram_len)

		return 0;

	for (i = *ppos; count > 0 && i < NVRAM_SIZE; ++i, ++p, --count) {

	for (i = *ppos; count > 0 && i < nvram_len; ++i, ++p, --count) {

		if (__get_user(c, p))

			return -EFAULT;

		nvram_write_byte(c, i);
@@ -133,9 +135,20 @@ static struct miscdevice nvram_dev = { 


int __init nvram_init(void)

{

	int ret = 0;



	printk(KERN_INFO "Generic non-volatile memory driver v%s\n",

		NVRAM_VERSION);

	return misc_register(&nvram_dev);

	ret = misc_register(&nvram_dev);

	if (ret != 0)

		goto out;



	nvram_len = nvram_get_size();

	if (nvram_len < 0)

		nvram_len = NVRAM_SIZE;



out:

	return ret;

}



void __exit nvram_cleanup(void)