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SubjectRe: [PATCH v3] ARM: EXYNOS: SWRESET is needed to boot secondary CPU on Exynos3250
On 09/24/14 21:30, Krzysztof Kozlowski wrote:
> 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>
>
> ---
>
> Changes since v2:
> 1. Rebase on Kukjin's for-next tree from 24th of September
> (v3.17-rc3-97-gbcf20e084a4b)
>
> Changes since v1:
> 1. Removed inline keyword and change if statement to early return as
> Tomasz suggested.
> 2. Added reviewed-by Tomasz Figa.
> ---
> arch/arm/mach-exynos/platsmp.c | 23 +++++++++++++++++++++++
> arch/arm/mach-exynos/regs-pmu.h | 2 ++
> 2 files changed, 25 insertions(+)
>
> diff --git a/arch/arm/mach-exynos/platsmp.c b/arch/arm/mach-exynos/platsmp.c
> index 41ae28d69e6f..8543064dc445 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,
> diff --git a/arch/arm/mach-exynos/regs-pmu.h b/arch/arm/mach-exynos/regs-pmu.h
> index 30c03017aa6a..4ea5e320c6d1 100644
> --- a/arch/arm/mach-exynos/regs-pmu.h
> +++ b/arch/arm/mach-exynos/regs-pmu.h
> @@ -21,6 +21,7 @@
> #define S5P_USE_STANDBY_WFI0 (1<< 16)
> #define S5P_USE_STANDBY_WFE0 (1<< 24)
>
> +#define EXYNOS_CORE_PO_RESET(n) ((1<< 4)<< n)
> #define EXYNOS_WAKEUP_FROM_LOWPWR (1<< 28)
> #define EXYNOS_SWRESET 0x0400
> #define EXYNOS5440_SWRESET 0x00C4
> @@ -125,6 +126,7 @@
> #define S5P_PAD_RET_EBIB_OPTION 0x31A8
>
> #define S5P_CORE_LOCAL_PWR_EN 0x3
> +#define S5P_CORE_WAKEUP_FROM_LOCAL_CFG (0x3<< 8)
>
> /* Only for EXYNOS4210 */
> #define S5P_CMU_CLKSTOP_LCD1_LOWPWR 0x1154

Applied, thanks.

- Kukjin


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