[RFC] ARM: EXYNOS: reset KFC cores when cpu is up

The cpu booting of exynos5422 has been still broken since we discussed
it in last year[1]. I found this resetting codes from odroid-xu3 kernel of
hardkernel, it could help to boot 8 cores well. This patch need to have
more test like STR and other SoC especially exynos5800 which is variant
of exynos5422. If this patch is broken on exynos5800, I'll find another
way to check exynos5422.

This patch is top of my previous exynos5422 cpu ordering patch[2] and
need to enable CONFIG_EXYNOS5420_MCPM=y

[    0.047509] CPU0: update cpu_capacity 448
[    0.047534] CPU0: thread -1, cpu 0, socket 1, mpidr 80000100
[    0.047874] Setting up static identity map for 0x400082c0 -
0x40008318
[    0.048340] ARM CCI driver probed
[    0.048597] Exynos MCPM support installed
[    0.065676] CPU1: update cpu_capacity 448
[    0.065685] CPU1: thread -1, cpu 1, socket 1, mpidr 80000101
[    0.070672] CPU2: update cpu_capacity 448
[    0.070680] CPU2: thread -1, cpu 2, socket 1, mpidr 80000102
[    0.075644] CPU3: update cpu_capacity 448
[    0.075653] CPU3: thread -1, cpu 3, socket 1, mpidr 80000103
[    0.080590] CPU4: update cpu_capacity 1535
[    0.080600] CPU4: thread -1, cpu 0, socket 0, mpidr 80000000
[    0.085591] CPU5: update cpu_capacity 1535
[    0.085599] CPU5: thread -1, cpu 1, socket 0, mpidr 80000001
[    0.090590] CPU6: update cpu_capacity 1535
[    0.090598] CPU6: thread -1, cpu 2, socket 0, mpidr 80000002
[    0.095585] CPU7: update cpu_capacity 1535
[    0.095593] CPU7: thread -1, cpu 3, socket 0, mpidr 80000003
[    0.095720] Brought up 8 CPUs

[1]:http://lists.infradead.org/pipermail/linux-arm-kernel/2015-June/350632.html
[2]:https://patchwork.kernel.org/patch/6782891/

Cc: Joonyoung Shim <redacted>
Cc: Chanwoo Choi <cw00.choi@samsung.com>
Cc: Kevin Hilman <khilman@kernel.org>
Cc: Heesub Shin <redacted>
Cc: Mauro Ribeiro <redacted>
Cc: Abhilash Kesavan <redacted>
Cc: Przemyslaw Marczak <redacted>
Cc: Marek Szyprowski <m.szyprowski@samsung.com>
Cc: Krzysztof Kozlowski <redacted>
Signed-off-by: Chanho Park <redacted>
Signed-off-by: Chanho Park <redacted>
---
 arch/arm/mach-exynos/mcpm-exynos.c | 13 ++++++++++++-
 arch/arm/mach-exynos/regs-pmu.h    |  6 ++++++
 2 files changed, 18 insertions(+), 1 deletion(-)

diff --git a/arch/arm/mach-exynos/mcpm-exynos.c b/arch/arm/mach-exynos/mcpm-exynos.c
index 9bdf547..a076dde 100644
--- a/arch/arm/mach-exynos/mcpm-exynos.c
+++ b/arch/arm/mach-exynos/mcpm-exynos.c

@@ -70,7 +70,18 @@ static int exynos_cpu_powerup(unsigned int cpu, unsigned int cluster)
 		cluster >= EXYNOS5420_NR_CLUSTERS)
 		return -EINVAL;

-	exynos_cpu_power_up(cpunr);
+	if (!exynos_cpu_power_state(cpunr)) {
+		exynos_cpu_power_up(cpunr);
+
+		if (soc_is_exynos5800() && cluster) {
+			while (!pmu_raw_readl(S5P_PMU_SPARE2))
+				udelay(10);
+
+			pmu_raw_writel(EXYNOS5420_KFC_CORE_RESET(cpu),
+					EXYNOS_SWRESET);
+		}
+	}
+
 	return 0;
 }
 

diff --git a/arch/arm/mach-exynos/regs-pmu.h b/arch/arm/mach-exynos/regs-pmu.h
index b761433..fba9068 100644
--- a/arch/arm/mach-exynos/regs-pmu.h
+++ b/arch/arm/mach-exynos/regs-pmu.h

@@ -513,6 +513,12 @@ static inline unsigned int exynos_pmu_cpunr(unsigned int mpidr)
 #define SPREAD_ENABLE						0xF
 #define SPREAD_USE_STANDWFI					0xF
 
+#define EXYNOS5420_KFC_CORE_RESET0				BIT(8)
+#define EXYNOS5420_KFC_ETM_RESET0				BIT(20)
+
+#define EXYNOS5420_KFC_CORE_RESET(_nr)				\
+	((EXYNOS5420_KFC_CORE_RESET0 | EXYNOS5420_KFC_ETM_RESET0) << (_nr))
+
 #define EXYNOS5420_BB_CON1					0x0784
 #define EXYNOS5420_BB_SEL_EN					BIT(31)
 #define EXYNOS5420_BB_PMOS_EN					BIT(7)

-- 
2.1.0