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author | Shawn Guo <shawn.guo@linaro.org> | 2013-10-28 16:37:12 +0800 |
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committer | Shawn Guo <shawn.guo@linaro.org> | 2013-11-11 22:58:43 +0800 |
commit | b6e23bb63f28f0a8ffa7cf9824fa48000c08f9b2 (patch) | |
tree | 1de9655ee19ed89d161a3ba4d44ec08ae0e43b06 /arch/arm/mach-imx/system.c | |
parent | 9b3d423707c3b1f6633be1be7e959623e10c596b (diff) | |
download | blackbird-op-linux-b6e23bb63f28f0a8ffa7cf9824fa48000c08f9b2.tar.gz blackbird-op-linux-b6e23bb63f28f0a8ffa7cf9824fa48000c08f9b2.zip |
ARM: imx: remove imx_src_prepare_restart() call
There is ~10% possibility that the following emergency restart command
fails to reboot imx6q.
$ echo b > /proc/sysrq-trigger
The IMX restart routine mxc_restart() assumes that it will always run on
primary core, and will call imx_src_prepare_restart() to disable
secondary cores in order to get them come to online in the following
boot. However, the assumption is only true for normal kernel_restart()
case where migrate_to_reboot_cpu() will be called to migrate to primary
core, but not necessarily true for emergency_restart() case. So when
emergency_restart() calls into mxc_restart() on any secondary core,
system will hang immediately once imx_src_prepare_restart() is called
to disabled secondary cores. Since emergency_restart() is defined as a
function that is safe to call in interrupt context, we cannot just call
migrate_to_reboot_cpu() to fix the issue.
Fortunately, we just found that the issue can be fixed at imx6q platform
level. We used to call imx_src_prepare_restart() to disable all
secondary cores before resetting hardware. Otherwise, the secondary
will fail come to online in the reboot. However, we recently found that
after commit 6050d18 (ARM: imx: reset core along with enable/disable
operation) comes to play, we do not need to reset the secondary cores
any more. That said, mxc_restart() now can run on any core to reboot
the system, as long as we remove the imx_src_prepare_restart() call from
mxc_restart().
So let's simply remove imx_src_prepare_restart() call to fix the above
emergency restart failure.
Reported-by: Jiada Wang <jiada_wang@mentor.com>
Signed-off-by: Shawn Guo <shawn.guo@linaro.org>
Diffstat (limited to 'arch/arm/mach-imx/system.c')
-rw-r--r-- | arch/arm/mach-imx/system.c | 3 |
1 files changed, 0 insertions, 3 deletions
diff --git a/arch/arm/mach-imx/system.c b/arch/arm/mach-imx/system.c index e6edcd38b282..826b72ba08d9 100644 --- a/arch/arm/mach-imx/system.c +++ b/arch/arm/mach-imx/system.c @@ -42,9 +42,6 @@ void mxc_restart(enum reboot_mode mode, const char *cmd) { unsigned int wcr_enable; - if (cpu_is_imx6q() || cpu_is_imx6dl()) - imx_src_prepare_restart(); - if (wdog_clk) clk_enable(wdog_clk); |