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SubjectRe: [PATCH] ARM: imx: Add support for low power suspend on MX51.
Hi Dinh,

On Wed, Nov 03, 2010 at 05:52:09PM -0500, Dinh.Nguyen@freescale.com wrote:
> From: Dinh Nguyen <Dinh.Nguyen@freescale.com>
>
> Adds initial low power suspend functionality to MX51.
> Supports "mem" and "standby" modes.
>
> Signed-off-by: Dinh Nguyen <Dinh.Nguyen@freescale.com>
> ---
> arch/arm/mach-mx5/Makefile | 2 +-
> arch/arm/mach-mx5/pm.c | 92 ++++++++++++++++++++++++++++++++++
> arch/arm/plat-mxc/include/mach/mxc.h | 6 ++
> 3 files changed, 99 insertions(+), 1 deletions(-)
> create mode 100644 arch/arm/mach-mx5/pm.c
>
> diff --git a/arch/arm/mach-mx5/Makefile b/arch/arm/mach-mx5/Makefile
> index 462f177..aefc9a1 100644
> --- a/arch/arm/mach-mx5/Makefile
> +++ b/arch/arm/mach-mx5/Makefile
> @@ -3,7 +3,7 @@
> #
>
> # Object file lists.
> -obj-y := cpu.o mm.o clock-mx51.o devices.o
> +obj-y := cpu.o mm.o clock-mx51.o devices.o pm.o

pm.o should depend on CONFIG_PM

>
> obj-$(CONFIG_CPU_FREQ_IMX) += cpu_op-mx51.o
> obj-$(CONFIG_MACH_MX51_BABBAGE) += board-mx51_babbage.o
> diff --git a/arch/arm/mach-mx5/pm.c b/arch/arm/mach-mx5/pm.c
> new file mode 100644
> index 0000000..a32640e
> --- /dev/null
> +++ b/arch/arm/mach-mx5/pm.c
> @@ -0,0 +1,92 @@
> +/*
> + * Copyright (C) 2010 Freescale Semiconductor, Inc. All Rights Reserved.
> + *
> + * The code contained herein is licensed under the GNU General Public
> + * License. You may obtain a copy of the GNU General Public License
> + * Version 2 or later at the following locations:
> + *
> + * http://www.opensource.org/licenses/gpl-license.html
> + * http://www.gnu.org/copyleft/gpl.html
> + */
> +#include <linux/kernel.h>
> +#include <linux/suspend.h>
> +#include <linux/io.h>
> +#include <asm/cacheflush.h>
> +#include <asm/tlb.h>
> +#include <asm/mach/map.h>
> +#include <mach/system.h>
> +#include "crm_regs.h"

Please cleanup the include list. At least asm/cacheflush.h and asm/tlb.h
seem to be unused here.

> +
> +/* set cpu low power mode before WFI instruction */
> +static void mxc_cpu_lp_set(enum mxc_cpu_pwr_mode mode)
> +{
> + u32 plat_lpc, arm_srpgcr, ccm_clpcr;
> +
> + /* always allow platform to issue a deep sleep mode request */
> + plat_lpc = __raw_readl(MXC_CORTEXA8_PLAT_LPC) &
> + ~(MXC_CORTEXA8_PLAT_LPC_DSM);
> + ccm_clpcr = __raw_readl(MXC_CCM_CLPCR) & ~(MXC_CCM_CLPCR_LPM_MASK);
> + arm_srpgcr = __raw_readl(MXC_SRPG_ARM_SRPGCR) & ~(MXC_SRPGCR_PCR);
> +
> + switch (mode) {
> + case WAIT_UNCLOCKED_POWER_OFF:
> + case STOP_POWER_OFF:
> + plat_lpc |= MXC_CORTEXA8_PLAT_LPC_DSM
> + | MXC_CORTEXA8_PLAT_LPC_DBG_DSM;
> + if (mode == WAIT_UNCLOCKED_POWER_OFF) {
> + ccm_clpcr |= (0x1 << MXC_CCM_CLPCR_LPM_OFFSET);
> + ccm_clpcr &= ~MXC_CCM_CLPCR_VSTBY;
> + ccm_clpcr &= ~MXC_CCM_CLPCR_SBYOS;
> + } else {
> + ccm_clpcr |= (0x2 << MXC_CCM_CLPCR_LPM_OFFSET);
> + ccm_clpcr |= (0x3 << MXC_CCM_CLPCR_STBY_COUNT_OFFSET);
> + ccm_clpcr |= MXC_CCM_CLPCR_VSTBY;
> + ccm_clpcr |= MXC_CCM_CLPCR_SBYOS;
> + }
> + arm_srpgcr |= MXC_SRPGCR_PCR;
> + break;
> + default:
> + printk(KERN_WARNING "UNKNOWN cpu power mode: %d\n", mode);
> + return;
> + }
> +
> + __raw_writel(plat_lpc, MXC_CORTEXA8_PLAT_LPC);
> + __raw_writel(ccm_clpcr, MXC_CCM_CLPCR);
> + __raw_writel(arm_srpgcr, MXC_SRPG_ARM_SRPGCR);
> +}

Maybe you can put this code into mx5_suspend_enter. Definitely there is
no need to introduce an enum mxc_cpu_pwr_mode instead of passing
suspend_state_t directly.

> +
> +static int mx5_suspend_enter(suspend_state_t state)
> +{
> + switch (state) {
> + case PM_SUSPEND_MEM:
> + mxc_cpu_lp_set(STOP_POWER_OFF);
> + break;
> + case PM_SUSPEND_STANDBY:
> + mxc_cpu_lp_set(WAIT_UNCLOCKED_POWER_OFF);
> + break;
> + default:
> + return -EINVAL;
> + }
> +
> + if (tzic_enable_wake(0) != 0)
> + return -EAGAIN;
> + cpu_do_idle();
> + return 0;
> +}
> +
> +static int mx5_pm_valid(suspend_state_t state)
> +{
> + return (state > PM_SUSPEND_ON && state <= PM_SUSPEND_MAX);
> +}
> +
> +static const struct platform_suspend_ops mx5_suspend_ops = {
> + .valid = mx5_pm_valid,
> + .enter = mx5_suspend_enter,
> +};
> +
> +static int __init mx5_pm_init(void)
> +{
> + suspend_set_ops(&mx5_suspend_ops);
> + return 0;
> +}

Please protect this function with a cpu_is_mx51().

> +device_initcall(mx5_pm_init);
> diff --git a/arch/arm/plat-mxc/include/mach/mxc.h b/arch/arm/plat-mxc/include/mach/mxc.h
> index a42c720..ece13fc 100644
> --- a/arch/arm/plat-mxc/include/mach/mxc.h
> +++ b/arch/arm/plat-mxc/include/mach/mxc.h
> @@ -37,6 +37,12 @@
>
> #ifndef __ASSEMBLY__
> extern unsigned int __mxc_cpu_type;
> +
> +enum mxc_cpu_pwr_mode {
> + WAIT_UNCLOCKED_POWER_OFF, /* WAIT + SRPG */
> + STOP_POWER_OFF, /* STOP + SRPG */
> +};
> +int tzic_enable_wake(int is_idle);
> #endif
>
> #ifdef CONFIG_ARCH_MX1
> --
> 1.6.0.4
>
>
>

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