| Submitter | Kevin Cernekee |
|---|---|
| Date | April 15, 2010, 12:57 a.m. |
| Message ID | <a00f98bfcda7db841108605ebab8d07363f4aa8b@localhost.localdomain> |
| Download | mbox | patch |
| Permalink | /patch/50206/ |
| State | New |
| Headers | show |
Comments
On Wed, Apr 14, 2010 at 05:57:33PM -0700, Kevin Cernekee wrote: > Ensure that the flash device is in a quiescent state before rebooting. > The implementation is closely modeled after the cfe_cmdset_0001 reboot > notifier, commit 963a6fb0a0d336d0513083b7e4b5c3ff9d6d2061 . > > Signed-off-by: Kevin Cernekee <cernekee@gmail.com> Yes, if this is present for Intel, it should be present for AMD, IMHO. Acked-by: Wolfram Sang <w.sang@pengutronix.de> Still, the correct solution is to wire the correct reset-line to the flashes. Above patch will not help if a watchdog kicks in. Been there :( Regards, Wolfram
On Wed, 2010-04-14 at 17:57 -0700, Kevin Cernekee wrote: > Ensure that the flash device is in a quiescent state before rebooting. > The implementation is closely modeled after the cfe_cmdset_0001 reboot > notifier, commit 963a6fb0a0d336d0513083b7e4b5c3ff9d6d2061 . > > Signed-off-by: Kevin Cernekee <cernekee@gmail.com> > --- > drivers/mtd/chips/cfi_cmdset_0002.c | 56 +++++++++++++++++++++++++++++++++++ > 1 files changed, 56 insertions(+), 0 deletions(-) This patch conflicts with the patch from Stefani, which is sitting in my l2-mtd-2.6.git tree (http://git.infradead.org/users/dedekind/l2-mtd-2.6.git). Could you please amend it and re-send? The conflicting patch is: Author: Stefani Seibold <stefani@seibold.net> Date: Sun Apr 18 22:46:44 2010 +0200 mtd: fix a huge latency problem in the MTD CFI and LPDDR flash drivers. The use of a memcpy() during a spinlock operation will cause very long thread context switch delays if the flash chip bandwidth is low and the data to be copied large, because a spinlock will disable preemption. For example: A flash with 6,5 MB/s bandwidth will cause under ubifs, which request sometimes 128 KB (the flash erase size), a preemption delay of 20 milliseconds. High priority threads will not be served during this time, regardless whether this threads access the flash or not. This behavior breaks real time. The patch changes all the use of spin_lock operations for xxxx->mutex into mutex operations, which is exact what the name says and means. I have checked the code of the drivers and there is no use of atomic pathes like interrupt or timers. The mtdoops facility will also not be used by this drivers. So it is dave to replace the spin_lock against mutex. There is no performance regression since the mutex is normally not acquired. Changelog: 06.03.2010 First release 26.03.2010 Fix mutex[1] issue and tested it for compile failure Signed-off-by: Stefani Seibold <stefani@seibold.net> Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
Wolfram Sang wrote: > On Wed, Apr 14, 2010 at 05:57:33PM -0700, Kevin Cernekee wrote: > > Ensure that the flash device is in a quiescent state before rebooting. > > The implementation is closely modeled after the cfe_cmdset_0001 reboot > > notifier, commit 963a6fb0a0d336d0513083b7e4b5c3ff9d6d2061 . > > > > Signed-off-by: Kevin Cernekee <cernekee@gmail.com> > > Yes, if this is present for Intel, it should be present for AMD, IMHO. > > Acked-by: Wolfram Sang <w.sang@pengutronix.de> > > Still, the correct solution is to wire the correct reset-line to the flashes. > Above patch will not help if a watchdog kicks in. Been there :( Isn't the patch intended to handle _software_ resets where the hard reset line isn't toggled? -- Jamie
Patch
diff --git a/drivers/mtd/chips/cfi_cmdset_0002.c b/drivers/mtd/chips/cfi_cmdset_0002.c index ea2a7f6..f40d308 100644 --- a/drivers/mtd/chips/cfi_cmdset_0002.c +++ b/drivers/mtd/chips/cfi_cmdset_0002.c @@ -32,6 +32,7 @@ #include <linux/slab.h> #include <linux/delay.h> #include <linux/interrupt.h> +#include <linux/reboot.h> #include <linux/mtd/compatmac.h> #include <linux/mtd/map.h> #include <linux/mtd/mtd.h> @@ -56,6 +57,7 @@ static int cfi_amdstd_erase_varsize(struct mtd_info *, struct erase_info *); static void cfi_amdstd_sync (struct mtd_info *); static int cfi_amdstd_suspend (struct mtd_info *); static void cfi_amdstd_resume (struct mtd_info *); +static int cfi_amdstd_reboot(struct notifier_block *, unsigned long, void *); static int cfi_amdstd_secsi_read (struct mtd_info *, loff_t, size_t, size_t *, u_char *); static void cfi_amdstd_destroy(struct mtd_info *); @@ -351,6 +353,8 @@ struct mtd_info *cfi_cmdset_0002(struct map_info *map, int primary) mtd->name = map->name; mtd->writesize = 1; + mtd->reboot_notifier.notifier_call = cfi_amdstd_reboot; + if (cfi->cfi_mode==CFI_MODE_CFI){ unsigned char bootloc; /* @@ -487,6 +491,7 @@ static struct mtd_info *cfi_amdstd_setup(struct mtd_info *mtd) #endif __module_get(THIS_MODULE); + register_reboot_notifier(&mtd->reboot_notifier); return mtd; setup_err: @@ -628,6 +633,10 @@ static int get_chip(struct map_info *map, struct flchip *chip, unsigned long adr chip->state = FL_READY; return 0; + case FL_SHUTDOWN: + /* The machine is rebooting */ + return -EIO; + case FL_POINT: /* Only if there's no operation suspended... */ if (mode == FL_READY && chip->oldstate == FL_READY) @@ -1918,11 +1927,58 @@ static void cfi_amdstd_resume(struct mtd_info *mtd) } } + +/* + * Ensure that the flash device is put back into read array mode before + * unloading the driver or rebooting. On some systems, rebooting while + * the flash is in query/program/erase mode will prevent the CPU from + * fetching the bootloader code, requiring a hard reset or power cycle. + */ +static int cfi_amdstd_reset(struct mtd_info *mtd) +{ + struct map_info *map = mtd->priv; + struct cfi_private *cfi = map->fldrv_priv; + int i, ret; + struct flchip *chip; + + for (i = 0; i < cfi->numchips; i++) { + + chip = &cfi->chips[i]; + + spin_lock(chip->mutex); + + ret = get_chip(map, chip, chip->start, FL_SHUTDOWN); + if (!ret) { + map_write(map, CMD(0xF0), chip->start); + chip->state = FL_SHUTDOWN; + put_chip(map, chip, chip->start); + } + + spin_unlock(chip->mutex); + } + + return 0; +} + + +static int cfi_amdstd_reboot(struct notifier_block *nb, unsigned long val, + void *v) +{ + struct mtd_info *mtd; + + mtd = container_of(nb, struct mtd_info, reboot_notifier); + cfi_amdstd_reset(mtd); + return NOTIFY_DONE; +} + + static void cfi_amdstd_destroy(struct mtd_info *mtd) { struct map_info *map = mtd->priv; struct cfi_private *cfi = map->fldrv_priv; + cfi_amdstd_reset(mtd); + unregister_reboot_notifier(&mtd->reboot_notifier); kfree(cfi->cmdset_priv); kfree(cfi->cfiq); kfree(cfi);
Ensure that the flash device is in a quiescent state before rebooting. The implementation is closely modeled after the cfe_cmdset_0001 reboot notifier, commit 963a6fb0a0d336d0513083b7e4b5c3ff9d6d2061 . Signed-off-by: Kevin Cernekee <cernekee@gmail.com> --- drivers/mtd/chips/cfi_cmdset_0002.c | 56 +++++++++++++++++++++++++++++++++++ 1 files changed, 56 insertions(+), 0 deletions(-)