[PATCH v6 1/3] ARM: rockchip: fix the CPU soft reset
dianders at chromium.org
Tue Jun 9 11:16:56 PDT 2015
On Tue, Jun 9, 2015 at 2:49 AM, Caesar Wang <wxt at rock-chips.com> wrote:
> We need different orderings when turning a core on and turning a core
> off. In one case we need to assert reset before turning power off.
> In ther other case we need to turn power on and the deassert reset.
> In general, the correct flow is:
> CPU off:
> regmap_update_bits(pmu, PMU_PWRDN_CON, BIT(pd), BIT(pd))
> CPU on:
> regmap_update_bits(pmu, PMU_PWRDN_CON, BIT(pd), 0)
> This is needed for stressing CPU up/down, as per:
> cd /sys/devices/system/cpu/
> for i in $(seq 10000); do
> echo "================= $i ============"
> for j in $(seq 100); do
> while [[ "$(cat cpu1/online)$(cat cpu2/online)$(cat cpu3/online)" != "000"" ]]
> echo 0 > cpu1/online
> echo 0 > cpu2/online
> echo 0 > cpu3/online
> while [[ "$(cat cpu1/online)$(cat cpu2/online)$(cat cpu3/online)" != "111" ]]; do
> echo 1 > cpu1/online
> echo 1 > cpu2/online
> echo 1 > cpu3/online
> The following is reproducable log:
> [34466.186812] PM: noirq suspend of devices complete after 0.669 msecs
> [34466.186824] Disabling non-boot CPUs ...
> [34466.187509] CPU1: shutdown
> [34466.188672] CPU2: shutdown
> [34473.736627] Kernel panic - not syncing:Watchdog detected hard LOCKUP on cpu 0
> or others similar log:
> [ 4072.454453] CPU1: shutdown
> [ 4072.504436] CPU2: shutdown
> [ 4072.554426] CPU3: shutdown
> [ 4072.577827] CPU1: Booted secondary processor
> [ 4072.582611] CPU2: Booted secondary processor
> Tested by cpu up/down scripts, the results told us need delay more time
> before write the sram. The wait time is affected by many aspects
> (e.g: cpu frequency, bootrom frequency, sram frequency, bus speed, ...).
> Although the cpus other than cpu0 will write the sram, the speedy is
> no the same as cpu0, if the cpu0 early wake up, perhaps the other cpus
> can't startup. As we know, the cpu0 can wake up when the cpu1/2/3 write
> the 'sram+4/8' and send the sev.
> At the moment, 1ms delay will be happy work for cpu up/down scripts test.
> Signed-off-by: Caesar Wang <wxt at rock-chips.com>
> Reviewed-by: Doug Anderson <dianders at chromium.org>
Usually it's good to remove someone's "Reviewed-by" when you've made
as many changes as you have. ...but in this case I am still happy
with this patch, so I'll re-assert:
Reviewed-by: Douglas Anderson <dianders at chromium.org>
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