Hi On Thu, Jul 29, 2010 at 9:41 AM, Mikko Rapeli <ext-mikko.rapeli@xxxxxxxxx> wrote: > From: Mikko Rapeli <ext-mikko.rapeli@xxxxxxxxx> > > Original patch: http://marc.info/?l=linux-omap&m=126522625032441&w=2 > > "Removes TWL4030 sleep script prior to rebooting, only on OMAP3. This is > necessary since DPLL3 reset causes SYS_OFFMODE pin to go low, resulting > in the sleep script being executed on TWL4030. This usually results in > VDD1 & VDD2 voltage collapse while ROM code is executing, followed by an > MPU Watch Dog reset or worse, an irrecoverable hang." I had a similar issue when my system hanged on hard reset when there was a TWL sleep script installed. The workaround I've found was to install the sleep script immediately before entering the suspend state and remove the script on the resume path. If you think that such approach is appropriate I can send a patch. > Original patch resulted in a crash due to sleeping i2c calls late in the > reboot sequence. Here's how to trigger the crash: > > # cat /dev/urandom > /foo & > sync(); > reboot(LINUX_REBOOT_CMD_RESTART2); > > Kernel trace from 2.6.32: > > Unable to handle kernel NULL pointer dereference at virtual address 00000000 > pgd = c0004000 > [00000000] *pgd=00000000 > Internal error: Oops: 805 [#2] PREEMPT > ... > [<c00b3210>] (exit_mmap+0x1d4/0x1f8) from [<c006069c>] (mmput+0x34/0x110) > [<c006069c>] (mmput+0x34/0x110) from [<c0064a90>] (exit_mm+0x140/0x180) > [<c0064a90>] (exit_mm+0x140/0x180) from [<c00668ec>] (do_exit+0x5d8/0x6ac) > [<c00668ec>] (do_exit+0x5d8/0x6ac) from [<c0035858>] (die+0x2d4/0x2e0) > [<c0035858>] (die+0x2d4/0x2e0) from [<c0035904>] (baddataabort+0x0/0x50) > [<c0035904>] (baddataabort+0x0/0x50) from [<c0274ff4>] (i2c_transfer+0xec/0x104) > [<c0274ff4>] (i2c_transfer+0xec/0x104) from [<00000001>] (0x1) > > Fix is to move reboot preparations into a reboot notifier. > > Signed-off-by: Mikko Rapeli <ext-mikko.rapeli@xxxxxxxxx> > Acked-by: Mike Turquette <mturquette@xxxxxx> > --- > > v2: added a new line after variable declarations > > v1: http://marc.info/?l=linux-omap&m=128031011323970&w=2 > > drivers/mfd/twl4030-power.c | 30 ++++++++++++++++++++++++++++++ > 1 files changed, 30 insertions(+), 0 deletions(-) > > diff --git a/drivers/mfd/twl4030-power.c b/drivers/mfd/twl4030-power.c > index 7efa878..5c6da1e 100644 > --- a/drivers/mfd/twl4030-power.c > +++ b/drivers/mfd/twl4030-power.c > @@ -28,6 +28,7 @@ > #include <linux/pm.h> > #include <linux/i2c/twl.h> > #include <linux/platform_device.h> > +#include <linux/reboot.h> > > #include <asm/mach-types.h> > > @@ -127,6 +128,30 @@ static u8 res_config_addrs[] = { > [RES_Main_Ref] = 0x94, > }; > > +/* > + * PRCM on OMAP3 will drive SYS_OFFMODE low during DPLL3 warm reset. > + * This causes Gaia sleep script to execute, usually killing VDD1 and > + * VDD2 while code is running. WA is to disable the sleep script > + * before warm reset. > + */ > +static int twl4030_prepare_for_reboot(struct notifier_block *this, > + unsigned long cmd, void *p) > +{ > + int err; > + > + err = twl4030_remove_script(TWL4030_SLEEP_SCRIPT); > + if (err) > + pr_err("TWL4030: error trying to disable sleep script!\n"); > + > + return NOTIFY_DONE; > +} > + > +static struct notifier_block twl4030_reboot_notifier = { > + .notifier_call = twl4030_prepare_for_reboot, > + .next = NULL, > + .priority = 0 > +}; > + > static int __init twl4030_write_script_byte(u8 address, u8 byte) > { > int err; > @@ -549,6 +574,11 @@ void __init twl4030_power_init(struct twl4030_power_data *twl4030_scripts) > err = twl_i2c_write_u8(TWL4030_MODULE_PM_MASTER, 0, R_PROTECT_KEY); > if (err) > pr_err("TWL4030 Unable to relock registers\n"); > + > + err = register_reboot_notifier(&twl4030_reboot_notifier); > + if (err) > + pr_err("TWL4030 Failed to register reboot notifier\n"); > + > return; > > unlock: > -- > 1.5.6.5 > > -- > To unsubscribe from this list: send the line "unsubscribe linux-omap" in > the body of a message to majordomo@xxxxxxxxxxxxxxx > More majordomo info at http://vger.kernel.org/majordomo-info.html > -- Sincerely Yours, Mike. -- To unsubscribe from this list: send the line "unsubscribe linux-omap" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
