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authorMartyn Welch <martyn.welch@gefanuc.com>2009-08-13 09:03:02 +0100
committerBenjamin Herrenschmidt <benh@kernel.crashing.org>2009-09-11 16:02:11 +1000
commitd331d8305cba713605854aab63a000fb892353a7 (patch)
tree5ee6cea2fe656d5772d79245e296c13b36f60456
parentpowerpc/iseries: Fix oops reading from /proc/iSeries/mf/*/cmdline (diff)
downloadlinux-dev-d331d8305cba713605854aab63a000fb892353a7.tar.xz
linux-dev-d331d8305cba713605854aab63a000fb892353a7.zip
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: Martyn Welch <martyn.welch@gefanuc.com> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
-rw-r--r--arch/powerpc/include/asm/nvram.h3
-rw-r--r--arch/powerpc/kernel/setup_32.c8
-rw-r--r--drivers/char/generic_nvram.c27
3 files changed, 31 insertions, 7 deletions
diff --git a/arch/powerpc/include/asm/nvram.h b/arch/powerpc/include/asm/nvram.h
index efde5ac82f7b..6c587eddee59 100644
--- a/arch/powerpc/include/asm/nvram.h
+++ b/arch/powerpc/include/asm/nvram.h
@@ -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);
diff --git a/arch/powerpc/kernel/setup_32.c b/arch/powerpc/kernel/setup_32.c
index e1e3059cf34b..53bcf3d792db 100644
--- a/arch/powerpc/kernel/setup_32.c
+++ b/arch/powerpc/kernel/setup_32.c
@@ -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)
diff --git a/drivers/char/generic_nvram.c b/drivers/char/generic_nvram.c
index a00869c650d5..ef31738c2cbe 100644
--- a/drivers/char/generic_nvram.c
+++ b/drivers/char/generic_nvram.c
@@ -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)