[PATCH v2 1/4] ARM: exynos: MCPM: Restore big.LITTLE cpuidle support

Marek Szyprowski m.szyprowski at samsung.com
Mon Jun 29 06:02:18 EDT 2020

Call exynos_cpu_power_up(cpunr) unconditionally. This is needed by the
big.LITTLE cpuidle driver and has no side-effects on other code paths.

The additional soft-reset call during little core power up has been added
to properly boot all cores on the Exynos5422-based boards with secure
firmware (like Odroid XU3/XU4 family). This however broke big.LITTLE
CPUidle driver, which worked only on boards without secure firmware (like
Peach-Pit/Pi Chromebooks). Apply the workaround only when board is
running under secure firmware.

Fixes: 833b5794e330 ("ARM: EXYNOS: reset Little cores when cpu is up")
Signed-off-by: Marek Szyprowski <m.szyprowski at samsung.com>
- adjusted patch subject to better describe the change
- added a comment about exynos_cpu_power_up(cpunr) call
 arch/arm/mach-exynos/mcpm-exynos.c | 10 +++++++---
 1 file changed, 7 insertions(+), 3 deletions(-)

diff --git a/arch/arm/mach-exynos/mcpm-exynos.c b/arch/arm/mach-exynos/mcpm-exynos.c
index 9a681b421ae1..cd861c57d5ad 100644
--- a/arch/arm/mach-exynos/mcpm-exynos.c
+++ b/arch/arm/mach-exynos/mcpm-exynos.c
@@ -26,6 +26,7 @@
 static void __iomem *ns_sram_base_addr __ro_after_init;
+static bool secure_firmware __ro_after_init;
  * The common v7_exit_coherency_flush API could not be used because of the
@@ -58,15 +59,16 @@ static void __iomem *ns_sram_base_addr __ro_after_init;
 static int exynos_cpu_powerup(unsigned int cpu, unsigned int cluster)
 	unsigned int cpunr = cpu + (cluster * EXYNOS5420_CPUS_PER_CLUSTER);
+	bool state;
 	pr_debug("%s: cpu %u cluster %u\n", __func__, cpu, cluster);
 	if (cpu >= EXYNOS5420_CPUS_PER_CLUSTER ||
 		cluster >= EXYNOS5420_NR_CLUSTERS)
 		return -EINVAL;
-	if (!exynos_cpu_power_state(cpunr)) {
-		exynos_cpu_power_up(cpunr);
+	state = exynos_cpu_power_state(cpunr);
+	exynos_cpu_power_up(cpunr);
+	if (!state && secure_firmware) {
 		 * This assumes the cluster number of the big cores(Cortex A15)
 		 * is 0 and the Little cores(Cortex A7) is 1.
@@ -258,6 +260,8 @@ static int __init exynos_mcpm_init(void)
 		return -ENOMEM;
+	secure_firmware = exynos_secure_firmware_available();
 	 * To increase the stability of KFC reset we need to program
 	 * the PMU SPARE3 register

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