[PATCH/RFC] ARM: shmobile: sh7372: Keep D4 pm domain powered
From: horms@verge.net.au (Simon Horman)
Date: 2014-10-27 01:08:47
Also in:
linux-pm, linux-sh
On Thu, Oct 23, 2014 at 01:31:14PM +0200, Geert Uytterhoeven wrote:
The D4 power domain contains the Coresight-ETM hardware block. As long as the ARM debug/perf code doesn't use resource management with runtime PM support, the D4 power domain must be kept powered to avoid a crash during resume from s2ram (dbg_cpu_pm_notify() calls reset_ctrl_regs() unconditionally, causing an undefined instruction oops). Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be> --- Untested on real hardware, but a similar workaround is needed on r8a7740.
I have hardware in the form of a Mackerel board and I'm happy to test this if it would help and you give me some guidance on how to do so.
quoted hunk ↗ jump to hunk
arch/arm/mach-shmobile/pm-sh7372.c | 12 ++++++++++++ 1 file changed, 12 insertions(+)diff --git a/arch/arm/mach-shmobile/pm-sh7372.c b/arch/arm/mach-shmobile/pm-sh7372.c index 7e5c2676c48902f1..cedffdd4b476adb4 100644 --- a/arch/arm/mach-shmobile/pm-sh7372.c +++ b/arch/arm/mach-shmobile/pm-sh7372.c@@ -77,6 +77,16 @@ #define PM_DOMAIN_ON_OFF_LATENCY_NS 250000 +static int sh7372_d4_pd_suspend(void) +{ + /* + * The D4 domain contains the Coresight-ETM hardware block and + * therefore it should only be turned off if the debug module is + * not in use. + */ + return -EBUSY; +} + static int sh7372_a4r_pd_suspend(void) { sh7372_intcs_suspend();@@ -131,6 +141,8 @@ static struct rmobile_pm_domain sh7372_pm_domains[] = { .genpd.power_on_latency_ns = PM_DOMAIN_ON_OFF_LATENCY_NS, .genpd.power_off_latency_ns = PM_DOMAIN_ON_OFF_LATENCY_NS, .bit_shift = 3, + .gov = &pm_domain_always_on_gov, + .suspend = sh7372_d4_pd_suspend, }, { .genpd.name = "A4R",-- 1.9.1