[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Message-ID: <YqkHto+zgAPs4kQI@worktop.programming.kicks-ass.net>
Date: Wed, 15 Jun 2022 00:12:06 +0200
From: Peter Zijlstra <peterz@...radead.org>
To: Tony Lindgren <tony@...mide.com>
Cc: rth@...ddle.net, ink@...assic.park.msu.ru, mattst88@...il.com,
vgupta@...nel.org, linux@...linux.org.uk,
ulli.kroll@...glemail.com, linus.walleij@...aro.org,
shawnguo@...nel.org, Sascha Hauer <s.hauer@...gutronix.de>,
kernel@...gutronix.de, festevam@...il.com, linux-imx@....com,
khilman@...nel.org, catalin.marinas@....com, will@...nel.org,
guoren@...nel.org, bcain@...cinc.com, chenhuacai@...nel.org,
kernel@...0n.name, geert@...ux-m68k.org, sammy@...my.net,
monstr@...str.eu, tsbogend@...ha.franken.de, dinguyen@...nel.org,
jonas@...thpole.se, stefan.kristiansson@...nalahti.fi,
shorne@...il.com, James.Bottomley@...senpartnership.com,
deller@....de, mpe@...erman.id.au, benh@...nel.crashing.org,
paulus@...ba.org, paul.walmsley@...ive.com, palmer@...belt.com,
aou@...s.berkeley.edu, hca@...ux.ibm.com, gor@...ux.ibm.com,
agordeev@...ux.ibm.com, borntraeger@...ux.ibm.com,
svens@...ux.ibm.com, ysato@...rs.sourceforge.jp, dalias@...c.org,
davem@...emloft.net, richard@....at,
anton.ivanov@...bridgegreys.com, johannes@...solutions.net,
tglx@...utronix.de, mingo@...hat.com, bp@...en8.de,
dave.hansen@...ux.intel.com, x86@...nel.org, hpa@...or.com,
acme@...nel.org, mark.rutland@....com,
alexander.shishkin@...ux.intel.com, jolsa@...nel.org,
namhyung@...nel.org, jgross@...e.com, srivatsa@...il.mit.edu,
amakhalov@...are.com, pv-drivers@...are.com,
boris.ostrovsky@...cle.com, chris@...kel.net, jcmvbkbc@...il.com,
rafael@...nel.org, lenb@...nel.org, pavel@....cz,
gregkh@...uxfoundation.org, mturquette@...libre.com,
sboyd@...nel.org, daniel.lezcano@...aro.org, lpieralisi@...nel.org,
sudeep.holla@....com, agross@...nel.org,
bjorn.andersson@...aro.org, anup@...infault.org,
thierry.reding@...il.com, jonathanh@...dia.com,
jacob.jun.pan@...ux.intel.com, Arnd Bergmann <arnd@...db.de>,
yury.norov@...il.com, andriy.shevchenko@...ux.intel.com,
linux@...musvillemoes.dk, rostedt@...dmis.org, pmladek@...e.com,
senozhatsky@...omium.org, john.ogness@...utronix.de,
paulmck@...nel.org, frederic@...nel.org, quic_neeraju@...cinc.com,
josh@...htriplett.org, mathieu.desnoyers@...icios.com,
jiangshanlai@...il.com, joel@...lfernandes.org,
juri.lelli@...hat.com, vincent.guittot@...aro.org,
dietmar.eggemann@....com, bsegall@...gle.com, mgorman@...e.de,
bristot@...hat.com, vschneid@...hat.com, jpoimboe@...nel.org,
linux-alpha@...r.kernel.org, linux-kernel@...r.kernel.org,
linux-snps-arc@...ts.infradead.org,
linux-arm-kernel@...ts.infradead.org, linux-omap@...r.kernel.org,
linux-csky@...r.kernel.org, linux-hexagon@...r.kernel.org,
linux-ia64@...r.kernel.org, linux-m68k@...ts.linux-m68k.org,
linux-mips@...r.kernel.org, openrisc@...ts.librecores.org,
linux-parisc@...r.kernel.org, linuxppc-dev@...ts.ozlabs.org,
linux-riscv@...ts.infradead.org, linux-s390@...r.kernel.org,
linux-sh@...r.kernel.org, sparclinux@...r.kernel.org,
linux-um@...ts.infradead.org, linux-perf-users@...r.kernel.org,
virtualization@...ts.linux-foundation.org,
xen-devel@...ts.xenproject.org, linux-xtensa@...ux-xtensa.org,
linux-acpi@...r.kernel.org, linux-pm@...r.kernel.org,
linux-clk@...r.kernel.org, linux-arm-msm@...r.kernel.org,
linux-tegra@...r.kernel.org, linux-arch@...r.kernel.org,
rcu@...r.kernel.org
Subject: Re: [PATCH 34.5/36] cpuidle,omap4: Push RCU-idle into
omap4_enter_lowpower()
On Mon, Jun 13, 2022 at 03:39:05PM +0300, Tony Lindgren wrote:
> OMAP4 uses full SoC suspend modes as idle states, as such it needs the
> whole power-domain and clock-domain code from the idle path.
>
> All that code is not suitable to run with RCU disabled, as such push
> RCU-idle deeper still.
>
> Signed-off-by: Tony Lindgren <tony@...mide.com>
> ---
>
> Peter here's one more for your series, looks like this is needed to avoid
> warnings similar to what you did for omap3.
Thanks Tony!
I've had a brief look at omap2_pm_idle() and do I understand it right
that something like the below patch would reduce it to a simple 'WFI'?
What do I do with the rest of that code, because I don't think this
thing has a cpuidle driver to take over, effectively turning it into
dead code.
--- a/arch/arm/mach-omap2/pm24xx.c
+++ b/arch/arm/mach-omap2/pm24xx.c
@@ -126,10 +126,20 @@ static int omap2_allow_mpu_retention(voi
return 1;
}
-static void omap2_enter_mpu_retention(void)
+static void omap2_do_wfi(void)
{
const int zero = 0;
+ /* WFI */
+ asm("mcr p15, 0, %0, c7, c0, 4" : : "r" (zero) : "memory", "cc");
+}
+
+#if 0
+/*
+ * possible cpuidle implementation between WFI and full_retention above
+ */
+static void omap2_enter_mpu_retention(void)
+{
/* The peripherals seem not to be able to wake up the MPU when
* it is in retention mode. */
if (omap2_allow_mpu_retention()) {
@@ -146,8 +157,7 @@ static void omap2_enter_mpu_retention(vo
pwrdm_set_next_pwrst(mpu_pwrdm, PWRDM_POWER_ON);
}
- /* WFI */
- asm("mcr p15, 0, %0, c7, c0, 4" : : "r" (zero) : "memory", "cc");
+ omap2_do_wfi();
pwrdm_set_next_pwrst(mpu_pwrdm, PWRDM_POWER_ON);
}
@@ -161,6 +171,7 @@ static int omap2_can_sleep(void)
return 1;
}
+#endif
static void omap2_pm_idle(void)
{
@@ -169,6 +180,7 @@ static void omap2_pm_idle(void)
if (omap_irq_pending())
return;
+#if 0
error = cpu_cluster_pm_enter();
if (error || !omap2_can_sleep()) {
omap2_enter_mpu_retention();
@@ -179,6 +191,9 @@ static void omap2_pm_idle(void)
out_cpu_cluster_pm:
cpu_cluster_pm_exit();
+#else
+ omap2_do_wfi();
+#endif
}
static void __init prcm_setup_regs(void)
Powered by blists - more mailing lists