ARM: EXYNOS: SWRESET is needed to boot secondary CPU on exynos3250

Without software reset the secondary CPU does not power up and
exynos_boot_secondary() ends with pen_release equal to 1. This can be
observed in dmesg:
	CPU1: failed to come online
	Brought up 1 CPUs
	SMP: Total of 1 processors activated.
	CPU: All CPU(s) started in SVC mode.

When booting the secondary CPU on Exynos3250 execute also software
reset for core 1.

Signed-off-by: Krzysztof Kozlowski <k.kozlowski@samsung.com>
Reviewed-by: Tomasz Figa <t.figa@samsung.com>
Signed-off-by: Kukjin Kim <kgene.kim@samsung.com>

1 files changed, 23 insertions, 0 deletions

diff --git a/arch/arm/mach-exynos/platsmp.c b/arch/arm/mach-exynos/platsmp.c
index 41ae28d..8543064 100644
--- a/arch/arm/mach-exynos/platsmp.c
+++ b/arch/arm/mach-exynos/platsmp.c
@@ -121,6 +121,26 @@ static inline void __iomem *cpu_boot_reg(int cpu)
 }
 
 /*
+ * Set wake up by local power mode and execute software reset for given core.
+ *
+ * Currently this is needed only when booting secondary CPU on Exynos3250.
+ */
+static void exynos_core_restart(u32 core_id)
+{
+	u32 val;
+
+	if (!of_machine_is_compatible("samsung,exynos3250"))
+		return;
+
+	val = pmu_raw_readl(EXYNOS_ARM_CORE_STATUS(core_id));
+	val |= S5P_CORE_WAKEUP_FROM_LOCAL_CFG;
+	pmu_raw_writel(val, EXYNOS_ARM_CORE_STATUS(core_id));
+
+	pr_info("CPU%u: Software reset\n", core_id);
+	pmu_raw_writel(EXYNOS_CORE_PO_RESET(core_id), EXYNOS_SWRESET);
+}
+
+/*
  * Write pen_release in a way that is guaranteed to be visible to all
  * observers, irrespective of whether they're taking part in coherency
  * or not.  This is necessary for the hotplug code to work reliably.
@@ -196,6 +216,9 @@ static int exynos_boot_secondary(unsigned int cpu, struct task_struct *idle)
 			return -ETIMEDOUT;
 		}
 	}
+
+	exynos_core_restart(core_id);
+
 	/*
 	 * Send the secondary CPU a soft interrupt, thereby causing
 	 * the boot monitor to read the system wide flags register,