[PATCH v3 2/2] ARM: kirkwood: Add standby support

[Ezequiel Garcia]

On Thu, Aug 22, 2013 at 12:49:07PM -0300, Ezequiel Garcia wrote:
> Implements standby support for Kirkwood SoC. When the SoC enters
> standby state the memory PM units are disabled, the DDR is set
> in self-refresh mode, and the CPU is set in WFI.
> 
> At this point there's no clock gating, as that is considered each
> driver's task.
> 
> Signed-off-by: Simon Guinot <sguinot at lacie.com>
> Signed-off-by: Ezequiel Garcia <ezequiel.garcia at free-electrons.com>
> ---
>  arch/arm/mach-kirkwood/Makefile                   |  2 +
>  arch/arm/mach-kirkwood/board-dt.c                 |  1 +
>  arch/arm/mach-kirkwood/common.c                   |  1 +
>  arch/arm/mach-kirkwood/common.h                   |  6 ++
>  arch/arm/mach-kirkwood/include/mach/bridge-regs.h |  2 +
>  arch/arm/mach-kirkwood/pm.c                       | 73 +++++++++++++++++++++++
>  6 files changed, 85 insertions(+)
>  create mode 100644 arch/arm/mach-kirkwood/pm.c
> 
> diff --git a/arch/arm/mach-kirkwood/Makefile b/arch/arm/mach-kirkwood/Makefile
> index ac4cd75..ac78dcc 100644
> --- a/arch/arm/mach-kirkwood/Makefile
> +++ b/arch/arm/mach-kirkwood/Makefile
> @@ -1,4 +1,6 @@
>  obj-y				+= common.o irq.o pcie.o mpp.o
> +obj-$(CONFIG_PM)		+= pm.o
> +
>  
>  obj-$(CONFIG_MACH_D2NET_V2)		+= d2net_v2-setup.o lacie_v2-common.o
>  obj-$(CONFIG_MACH_DOCKSTAR)		+= dockstar-setup.o
> diff --git a/arch/arm/mach-kirkwood/board-dt.c b/arch/arm/mach-kirkwood/board-dt.c
> index 6e122ed..2d4a4aa 100644
> --- a/arch/arm/mach-kirkwood/board-dt.c
> +++ b/arch/arm/mach-kirkwood/board-dt.c
> @@ -96,6 +96,7 @@ static void __init kirkwood_dt_init(void)
>  	/* Setup root of clk tree */
>  	kirkwood_of_clk_init();
>  
> +	kirkwood_pm_init();
>  	kirkwood_cpuidle_init();
>  
>  #ifdef CONFIG_KEXEC
> diff --git a/arch/arm/mach-kirkwood/common.c b/arch/arm/mach-kirkwood/common.c
> index e9238b5..aceb68a 100644
> --- a/arch/arm/mach-kirkwood/common.c
> +++ b/arch/arm/mach-kirkwood/common.c
> @@ -717,6 +717,7 @@ void __init kirkwood_init(void)
>  	kirkwood_xor1_init();
>  	kirkwood_crypto_init();
>  
> +	kirkwood_pm_init();
>  	kirkwood_cpuidle_init();
>  #ifdef CONFIG_KEXEC
>  	kexec_reinit = kirkwood_enable_pcie;
> diff --git a/arch/arm/mach-kirkwood/common.h b/arch/arm/mach-kirkwood/common.h
> index fcf3ba6..2be1226 100644
> --- a/arch/arm/mach-kirkwood/common.h
> +++ b/arch/arm/mach-kirkwood/common.h
> @@ -58,6 +58,12 @@ void kirkwood_cpufreq_init(void);
>  void kirkwood_restart(enum reboot_mode, const char *);
>  void kirkwood_clk_init(void);
>  
> +#ifdef CONFIG_PM
> +void kirkwood_pm_init(void);
> +#else
> +static inline void kirkwood_pm_init(void) {};
> +#endif
> +
>  /* board init functions for boards not fully converted to fdt */
>  #ifdef CONFIG_MACH_DREAMPLUG_DT
>  void dreamplug_init(void);
> diff --git a/arch/arm/mach-kirkwood/include/mach/bridge-regs.h b/arch/arm/mach-kirkwood/include/mach/bridge-regs.h
> index 91242c9..8b9d1c9 100644
> --- a/arch/arm/mach-kirkwood/include/mach/bridge-regs.h
> +++ b/arch/arm/mach-kirkwood/include/mach/bridge-regs.h
> @@ -78,4 +78,6 @@
>  #define CGC_TDM			(1 << 20)
>  #define CGC_RESERVED		(0x6 << 21)
>  
> +#define MEMORY_PM_CTRL		(BRIDGE_VIRT_BASE + 0x118)
> +
>  #endif
> diff --git a/arch/arm/mach-kirkwood/pm.c b/arch/arm/mach-kirkwood/pm.c
> new file mode 100644
> index 0000000..8783a71
> --- /dev/null
> +++ b/arch/arm/mach-kirkwood/pm.c
> @@ -0,0 +1,73 @@
> +/*
> + * Power Management driver for Marvell Kirkwood SoCs
> + *
> + * Copyright (C) 2013 Ezequiel Garcia <ezequiel at free-electrons.com>
> + * Copyright (C) 2010 Simon Guinot <sguinot at lacie.com>
> + *
> + * This program is free software; you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License,
> + * version 2 of the License.
> + *
> + * This program is distributed in the hope that it will be useful,
> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
> + * GNU General Public License for more details.
> + */
> +
> +#include <linux/kernel.h>
> +#include <linux/suspend.h>
> +#include <linux/io.h>
> +#include <mach/bridge-regs.h>
> +
> +static void __iomem *ddr_operation_base;
> +
> +static void kirkwood_low_power(void)
> +{
> +	u32 mem_pm_ctrl;
> +
> +	mem_pm_ctrl = readl(MEMORY_PM_CTRL);
> +
> +	/* Set peripherals to low-power mode */
> +	writel_relaxed(~0, MEMORY_PM_CTRL);
> +
> +	/* Set DDR in self-refresh */
> +	writel_relaxed(0x7, ddr_operation_base);
> +
> +	/*
> +	 * Set CPU in wait-for-interrupt state.
> +	 * This disables the CPU core clocks,
> +	 * the array clocks, and also the L2 controller.
> +	 */
> +	cpu_do_idle();
> +
> +	writel_relaxed(mem_pm_ctrl, MEMORY_PM_CTRL);
> +}
> +
> +static int kirkwood_suspend_enter(suspend_state_t state)
> +{
> +	switch (state) {
> +	case PM_SUSPEND_STANDBY:
> +		kirkwood_low_power();
> +		break;
> +	default:
> +		return -EINVAL;
> +	}
> +	return 0;
> +}
> +
> +static int kirkwood_pm_valid_standby(suspend_state_t state)
> +{
> +	return state == PM_SUSPEND_STANDBY;
> +}
> +
> +static const struct platform_suspend_ops kirkwood_suspend_ops = {
> +	.enter = kirkwood_suspend_enter,
> +	.valid = kirkwood_pm_valid_standby,
> +};
> +
> +int __init kirkwood_pm_init(void)
> +{
> +	ddr_operation_base = ioremap(DDR_OPERATION_BASE, 4);
> +	suspend_set_ops(&kirkwood_suspend_ops);
> +	return 0;
> +}
> -- 
> 1.8.1.5
> 

Any comments on this?
-- 
Ezequiel García, Free Electrons
Embedded Linux, Kernel and Android Engineering
http://free-electrons.com