[PATCH v3 39/51] arm,omap2: Use WFI for omap2_pm_idle()

Peter Zijlstra
2023-01-12T21:55:10Z

arch_cpu_idle() is a very simple idle interface and exposes only a
single idle state and is expected to not require RCU and not do any
tracing/instrumentation.

As such, omap2_pm_idle() is not a valid implementation. Replace it
with a simple (shallow) omap2_do_wfi() call.

Omap2 doesn't have a cpuidle driver; but adding one would be the
recourse to (re)gain the other idle states.

Suggested-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Frederic Weisbecker <frederic@kernel.org>
Tested-by: Tony Lindgren <tony@atomide.com>
Tested-by: Ulf Hansson <ulf.hansson@linaro.org>
---
arch/arm/mach-omap2/pm24xx.c | 51 +------------------------------------------
1 file changed, 2 insertions(+), 49 deletions(-)

--- a/arch/arm/mach-omap2/pm24xx.c
+++ b/arch/arm/mach-omap2/pm24xx.c
@@ -116,50 +116,12 @@ static int omap2_enter_full_retention(vo

static int sti_console_enabled;

-static int omap2_allow_mpu_retention(void)
-{
- if (!omap2xxx_cm_mpu_retention_allowed())
- return 0;
- if (sti_console_enabled)
- return 0;
-
- return 1;
-}
-
-static void omap2_enter_mpu_retention(void)
+static void omap2_do_wfi(void)
{
const int zero = 0;

- /* The peripherals seem not to be able to wake up the MPU when
- * it is in retention mode. */
- if (omap2_allow_mpu_retention()) {
- /* REVISIT: These write to reserved bits? */
- omap_prm_clear_mod_irqs(CORE_MOD, PM_WKST1, ~0);
- omap_prm_clear_mod_irqs(CORE_MOD, OMAP24XX_PM_WKST2, ~0);
- omap_prm_clear_mod_irqs(WKUP_MOD, PM_WKST, ~0);
-
- /* Try to enter MPU retention */
- pwrdm_set_next_pwrst(mpu_pwrdm, PWRDM_POWER_RET);
-
- } else {
- /* Block MPU retention */
- pwrdm_set_next_pwrst(mpu_pwrdm, PWRDM_POWER_ON);
- }
-
/* WFI */
asm("mcr p15, 0, %0, c7, c0, 4" : : "r" (zero) : "memory", "cc");
-
- pwrdm_set_next_pwrst(mpu_pwrdm, PWRDM_POWER_ON);
-}
-
-static int omap2_can_sleep(void)
-{
- if (omap2xxx_cm_fclks_active())
- return 0;
- if (__clk_is_enabled(osc_ck))
- return 0;
-
- return 1;
}

static void omap2_pm_idle(void)
@@ -169,16 +131,7 @@ static void omap2_pm_idle(void)
if (omap_irq_pending())
return;

- error = cpu_cluster_pm_enter();
- if (error || !omap2_can_sleep()) {
- omap2_enter_mpu_retention();
- goto out_cpu_cluster_pm;
- }
-
- omap2_enter_full_retention();
-
-out_cpu_cluster_pm:
- cpu_cluster_pm_exit();
+ omap2_do_wfi();
}

static void __init prcm_setup_regs(void)