>>-----Original Message----- >>From: linux-omap-owner@xxxxxxxxxxxxxxx [mailto:linux-omap-owner@xxxxxxxxxxxxxxx] On Behalf Of Mikko >>Rapeli >>Sent: Wednesday, July 28, 2010 3:12 PM >>To: linux-omap@xxxxxxxxxxxxxxx >>Cc: Turquette, Mike; sameo@xxxxxxxxxxxxxxx >>Subject: [PATCH] twl4030 reboot workaround >> >>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; Minor nit. Insert a blank line. Regards Thara >>+ 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 -- 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
