Hi,
ldy647 <ldy...@163.com> writes:
> recently, when we install our wireless router, we found when we run
> the reboot command, the board couldn't restart. We hope you could lend
> us a hand to solve this problem. We'll be quite grateful for what you
> do for us.
Apparently MT7620 can't handle 4 byte addressing mode of the flash
memory on hardware (probably ROM bootloader) level so it needs to be
reset somehow prior to resetting the SoC. Some SoCs have a special
output from the watchdog to reset all the on-board peripherals, it
should be connected to the !RESET pin of the flash as well. And the
kernel should then use the watchdog driver to cause a reboot.
As a workaround when hardware modification is not possible and the
flash IC supports a reset command, you can use a patch like this (in
some cases when the kernel is completely stuck it won't help to reboot
of course, as the watchdog will fire on hardware level automatically,
if configured):
diff --git a/drivers/mtd/devices/m25p80.c b/drivers/mtd/devices/m25p80.c
index b298466..932f307 100644
--- a/drivers/mtd/devices/m25p80.c
+++ b/drivers/mtd/devices/m25p80.c
@@ -21,6 +21,7 @@
#include <linux/module.h>
#include <linux/device.h>
#include <linux/interrupt.h>
+#include <linux/reboot.h>
#include <linux/mutex.h>
#include <linux/math64.h>
#include <linux/slab.h>
@@ -61,6 +62,9 @@
/* Used for Spansion flashes only. */
#define OPCODE_BRWR 0x17 /* Bank register write */
+#define OPCODE_RESET_ENABLE 0x66
+#define OPCODE_RESET 0x99
+
/* Status Register bits. */
#define SR_WIP 1 /* Write in progress */
#define SR_WEL 2 /* Write enable latch */
@@ -907,6 +911,21 @@ static const struct spi_device_id *jedec_probe(struct
spi_device *spi)
return ERR_PTR(-ENODEV);
}
+static int m25p80_reboot(struct notifier_block *nb, unsigned long val,
+ void *v)
+{
+ struct mtd_info *mtd;
+
+ mtd = container_of(nb, struct mtd_info, reboot_notifier);
+ struct m25p *flash = mtd_to_m25p(mtd);
+
+ flash->command[0] = OPCODE_RESET_ENABLE;
+ spi_write(flash->spi, flash->command, 1);
+ flash->command[0] = OPCODE_RESET;
+ spi_write(flash->spi, flash->command, 1);
+
+ return NOTIFY_DONE;
+}
/*
* board specific setup should have ensured the SPI clock used here
@@ -1010,6 +1029,7 @@ static int m25p_probe(struct spi_device *spi)
flash->mtd.size = info->sector_size * info->n_sectors;
flash->mtd._erase = m25p80_erase;
flash->mtd._read = m25p80_read;
+ flash->mtd.reboot_notifier.notifier_call = m25p80_reboot;
/* flash protection support for STmicro chips */
if (JEDEC_MFR(info->jedec_id) == CFI_MFR_ST) {
@@ -1085,6 +1105,7 @@ static int m25p_probe(struct spi_device *spi)
flash->mtd.eraseregions[i].numblocks);
+ register_reboot_notifier(&flash->mtd.reboot_notifier);
/* partitions should match sector boundaries; and it may be good to
* use readonly partitions for writeprotected sectors (BP2..BP0).
*/
@@ -1099,6 +1120,8 @@ static int m25p_remove(struct spi_device *spi)
struct m25p *flash = dev_get_drvdata(&spi->dev);
int status;
+ unregister_reboot_notifier(&flash->mtd.reboot_notifier);
+
/* Clean up MTD stuff. */
status = mtd_device_unregister(&flash->mtd);
if (status == 0) {
--
Be free, use free (http://www.gnu.org/philosophy/free-sw.html) software!
mailto:fercer...@gmail.com
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