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>
diff --git a/drivers/char/generic_nvram.c b/drivers/char/generic_nvram.c
index a00869c..ef31738 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 @@
offset += file->f_pos;
break;
case 2:
- offset += NVRAM_SIZE;
+ offset += nvram_len;
break;
}
if (offset < 0) {
@@ -56,9 +58,9 @@
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 @@
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 @@
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)
