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MIPS: BCM47XX: Use mtd as an alternative way/API to get NVRAM content

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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@gmail.com>
Acked-by: Hauke Mehrtens <hauke@hauke-m.de>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/8266/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
This commit is contained in:
Rafał Miłecki 2014-10-29 10:05:06 +01:00 committed by Ralf Baechle
parent f4af6fb2fc
commit 9d1d08646a
1 changed files with 38 additions and 4 deletions
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42
arch/mips/bcm47xx/nvram.c
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@ -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;
}