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." 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> --- drivers/mfd/twl4030-power.c | 29 +++++++++++++++++++++++++++++ 1 files changed, 29 insertions(+), 0 deletions(-) diff --git a/drivers/mfd/twl4030-power.c b/drivers/mfd/twl4030-power.c index 7efa878..5d46768 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 +128,29 @@ 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 +573,11 @@ 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
