NVRAM can be read using magic memory offset, but after all it's just a
flash partition. On platforms where NVRAM isn't needed early we can get
it using mtd subsystem.
Signed-off-by: Rafał Miłecki <zajec5@xxxxxxxxx>
---
Changes since RFC:
1) Less #ifdef mess
2) Use err = mtd_read(..);
(with these changes all issues reported by Hauke were handled)
3) Clean #include-s
I successfully use this code on ARM for months.
---
arch/mips/bcm47xx/nvram.c | 42 ++++++++++++++++++++++++++++++++++++++----
1 file changed, 38 insertions(+), 4 deletions(-)
diff --git a/arch/mips/bcm47xx/nvram.c b/arch/mips/bcm47xx/nvram.c
index 21712fb..8b64991 100644
--- a/arch/mips/bcm47xx/nvram.c
+++ b/arch/mips/bcm47xx/nvram.c
@@ -13,12 +13,10 @@
#include <linux/types.h>
#include <linux/module.h>
-#include <linux/ssb/ssb.h>
#include <linux/kernel.h>
#include <linux/string.h>
-#include <asm/addrspace.h>
+#include <linux/mtd/mtd.h>
#include <bcm47xx_nvram.h>
-#include <asm/mach-bcm47xx/bcm47xx.h>
static char nvram_buf[NVRAM_SPACE];
static const u32 nvram_sizes[] = {0x8000, 0xF000, 0x10000};
@@ -123,7 +121,43 @@ int bcm47xx_nvram_init_from_mem(u32 base, u32 lim)
static int nvram_init(void)
{
- /* TODO: Look for MTD "nvram" partition */
+#ifdef CONFIG_MTD
+ struct mtd_info *mtd;
+ struct nvram_header header;
+ size_t bytes_read;
+ int err, i;
+
+ mtd = get_mtd_device_nm("nvram");
+ if (IS_ERR(mtd))
+ return -ENODEV;
+
+ for (i = 0; i < ARRAY_SIZE(nvram_sizes); i++) {
+ loff_t from = mtd->size - nvram_sizes[i];
+
+ if (from < 0)
+ continue;
+
+ err = mtd_read(mtd, from, sizeof(header), &bytes_read,
+ (uint8_t *)&header);
+ if (!err && header.magic == NVRAM_HEADER) {
+ u8 *dst = (uint8_t *)nvram_buf;
+ size_t len = header.len;
+
+ if (header.len > NVRAM_SPACE) {
+ pr_err("nvram on flash (%i bytes) is bigger than the reserved space in memory, will just copy the first %i bytes\n",
+ header.len, NVRAM_SPACE);
+ len = NVRAM_SPACE;
+ }
+
+ err = mtd_read(mtd, from, len, &bytes_read, dst);
+ if (err)
+ return err;
+ memset(dst + bytes_read, 0x0, NVRAM_SPACE - bytes_read);
+
+ return 0;
+ }
+ }
+#endif
return -ENXIO;
}
--
1.8.4.5
