[PATCH v2 0/3] ARM: rockchip: fix the SMP

[PATCH v2 0/3] ARM: rockchip: fix the SMP

[Caesar Wang]

    Verified on url =
    https://chromium.googlesource.com/chromiumos/third_party/kernel/+/chromeos-3.14


Caesar Wang (3):
  ARM: rockchip: fix the CPU soft reset
  ARM: rockchip: ensure CPU to enter WFI/WFE state
  ARM: rockchip: fix the SMP code style

 arch/arm/mach-rockchip/platsmp.c | 56 +++++++++++++++++++++++++++-------------
 1 file changed, 38 insertions(+), 18 deletions(-)

-- 
1.9.1

[PATCH v2 1/3] ARM: rockchip: fix the CPU soft reset

[Caesar Wang]

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:
    reset_control_assert
    regmap_update_bits(pmu, PMU_PWRDN_CON, BIT(pd), BIT(pd))
    wait_for_power_domain_to_turn_off
CPU on:
    regmap_update_bits(pmu, PMU_PWRDN_CON, BIT(pd), 0)
    wait_for_power_domain_to_turn_on
    reset_control_deassert

This is needed for stressing CPU up/down, as per:

    cd /sys/devices/system/cpu/
    for i in $(seq 1000); do
      echo "================= $i ============"
        for j in $(seq 100); do
            while [[ "$(cat cpu1/online)$(cat cpu2/online)$(cat cpu3/online)" != "000" ]]; do
                echo 0 > cpu1/online
                echo 0 > cpu2/online
                echo 0 > cpu3/online
            done
            while [[ "$(cat cpu1/online)$(cat cpu2/online)$(cat cpu3/online)" != "111" ]]; do
                echo 1 > cpu1/online
                echo 1 > cpu2/online
                echo 1 > cpu3/online
            done
        done
    done

The following is reproducile 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
    .......

Signed-off-by: Caesar Wang <wxt@rock-chips.com>
---

 arch/arm/mach-rockchip/platsmp.c | 46 +++++++++++++++++++++++++++-------------
 1 file changed, 31 insertions(+), 15 deletions(-)

diff --git a/arch/arm/mach-rockchip/platsmp.c b/arch/arm/mach-rockchip/platsmp.c
index 5b4ca3c..1d4659e 100644
--- a/arch/arm/mach-rockchip/platsmp.c
+++ b/arch/arm/mach-rockchip/platsmp.c
@@ -88,28 +88,44 @@ static int pmu_set_power_domain(int pd, bool on)
 			return PTR_ERR(rstc);
 		}
 
-		if (on)
-			reset_control_deassert(rstc);
-		else
+		if (!on)
 			reset_control_assert(rstc);
 
-		reset_control_put(rstc);
-	}
+		ret = regmap_update_bits(pmu, PMU_PWRDN_CON, BIT(pd), val);
+		if (ret < 0) {
+			pr_err("%s: could not update power domain\n", __func__);
+			reset_control_put(rstc);
+			return ret;
+		}
 
-	ret = regmap_update_bits(pmu, PMU_PWRDN_CON, BIT(pd), val);
-	if (ret < 0) {
-		pr_err("%s: could not update power domain\n", __func__);
-		return ret;
-	}
+		ret = -1;
+		while (ret != on) {
+			ret = pmu_power_domain_is_on(pd);
+			if (ret < 0) {
+				pr_err("%s: could not read power domain state\n",
+				       __func__);
+				return ret;
+			}
+		}
 
-	ret = -1;
-	while (ret != on) {
-		ret = pmu_power_domain_is_on(pd);
+		if (on)
+			reset_control_deassert(rstc);
+	} else {
+		ret = regmap_update_bits(pmu, PMU_PWRDN_CON, BIT(pd), val);
 		if (ret < 0) {
-			pr_err("%s: could not read power domain state\n",
-				 __func__);
+			pr_err("%s: could not update power domain\n", __func__);
 			return ret;
 		}
+
+		ret = -1;
+		while (ret != on) {
+			ret = pmu_power_domain_is_on(pd);
+			if (ret < 0) {
+				pr_err("%s: could not read power domain state\n",
+				       __func__);
+				return ret;
+			}
+		}
 	}
 
 	return 0;
-- 
1.9.1

[PATCH v2 2/3] ARM: rockchip: ensure CPU to enter WFI/WFE state

[Caesar Wang]

In idle mode, core1/2/3 of Cortex-A17 should be either power off or in
WFI/WFE state.
we can delay 1ms to ensure the CPU enter WFI/WFE state.

Signed-off-by: Caesar Wang <wxt@rock-chips.com>
---

 arch/arm/mach-rockchip/platsmp.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/arch/arm/mach-rockchip/platsmp.c b/arch/arm/mach-rockchip/platsmp.c
index 1d4659e..17b3473 100644
--- a/arch/arm/mach-rockchip/platsmp.c
+++ b/arch/arm/mach-rockchip/platsmp.c
@@ -335,6 +335,9 @@ static void __init rockchip_smp_prepare_cpus(unsigned int max_cpus)
 #ifdef CONFIG_HOTPLUG_CPU
 static int rockchip_cpu_kill(unsigned int cpu)
 {
+	/* ensure CPU can enter the WFI/WFE state */
+	mdelay(1);
+
 	pmu_set_power_domain(0 + cpu, false);
 	return 1;
 }
-- 
1.9.1

[PATCH v2 3/3] ARM: rockchip: fix the SMP code style

[Caesar Wang]

Use the below scripts to check:
scripts/checkpatch.pl -f --subject arch/arm/mach-rockchip/platsmp.c
Although there is a check, it's no matter.

CHECK: usleep_range is preferred over udelay; see
Documentation/timers/timers-howto.txt
+167udelay(10);
total: 0 errors, 0 warnings, 1 checks, 362 lines checked

 Changes in v2:
    - As Kever points out, Fix the subject typo WIF/WFI in PATCH [2/3].
    - As Heiko suggestion, re-adjust the cpu on/off flow in PATCH [1/3].
    - Use the checkpatch.pl -f --subjective to check in PATCH [3/3].

Signed-off-by: Caesar Wang <wxt@rock-chips.com>
---

 arch/arm/mach-rockchip/platsmp.c | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/arch/arm/mach-rockchip/platsmp.c b/arch/arm/mach-rockchip/platsmp.c
index 17b3473..fc50e1f 100644
--- a/arch/arm/mach-rockchip/platsmp.c
+++ b/arch/arm/mach-rockchip/platsmp.c
@@ -147,7 +147,7 @@ static int __cpuinit rockchip_boot_secondary(unsigned int cpu,
 
 	if (cpu >= ncores) {
 		pr_err("%s: cpu %d outside maximum number of cpus %d\n",
-							__func__, cpu, ncores);
+		       __func__, cpu, ncores);
 		return -ENXIO;
 	}
 
@@ -166,7 +166,7 @@ static int __cpuinit rockchip_boot_secondary(unsigned int cpu,
 		 * */
 		udelay(10);
 		writel(virt_to_phys(rockchip_secondary_startup),
-			sram_base_addr + 8);
+		       sram_base_addr + 8);
 		writel(0xDEADBEAF, sram_base_addr + 4);
 		dsb_sev();
 	}
@@ -345,7 +345,7 @@ static int rockchip_cpu_kill(unsigned int cpu)
 static void rockchip_cpu_die(unsigned int cpu)
 {
 	v7_exit_coherency_flush(louis);
-	while(1)
+	while (1)
 		cpu_do_idle();
 }
 #endif
@@ -358,4 +358,5 @@ static struct smp_operations rockchip_smp_ops __initdata = {
 	.cpu_die		= rockchip_cpu_die,
 #endif
 };
+
 CPU_METHOD_OF_DECLARE(rk3066_smp, "rockchip,rk3066-smp", &rockchip_smp_ops);
-- 
1.9.1