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Date: Thu, 17 May 2012 09:34:26 -0500
From: Rob Lee <rob.lee@...aro.org>
To: Sascha Hauer <s.hauer@...gutronix.de>
Cc: kernel@...gutronix.de, shawn.guo@...aro.org,
u.kleine-koenig@...gutronix.de, richard.zhao@...escale.com,
amit.kucheria@...aro.org, daniel.lezcano@...aro.org,
linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org,
linaro-dev@...ts.linaro.org, patches@...aro.org, jj@...osbits.net
Subject: Re: [PATCH v4 3/7] ARM: imx: clean and consolidate imx5 suspend and
idle code
On Wed, May 16, 2012 at 12:38 PM, Sascha Hauer <s.hauer@...gutronix.de> wrote:
> Hi Robert,
>
> Overall this looks ok now, some comments inline.
>
> Sascha
>
> On Tue, May 15, 2012 at 09:33:32PM -0500, Robert Lee wrote:
>> The imx5 idle code that existed in mm-imx5.c is moved to pm-imx5.c.
>> The imx5_pm_init call is now exported and called during the
>> MACHINE_START late_init in supported imx5 platforms.
>>
>> Remove various enabling/disabling of the gpc_dvfs clock and
>> enable it once during initialization. This is a very low
>> power clock that must be enabled during low power operations.
>>
>> There are only two "suspend_state_t" imx5 low power modes ever
>> used. STOP_POWER_OFF for suspend to mem and
>> WAIT_UNCLOCKED_POWER_OFF for idle and suspend to standby. The
>> latter mode only requires 500 nanoseconds of extra hardware
>> exit time beyond a basic WFI operation (WAIT_CLOCKED mode) so
>> no other idle mode is necessary. Given this information, it
>> is more efficient to keep the registers in the often used
>> WAIT_UNCLOCKED_POWER_OFF state and only to and from the
>> STOP_POWER_OFF register state as needed when suspend to
>> mem is required.
>>
>> Signed-off-by: Robert Lee <rob.lee@...aro.org>
>> ---
>> arch/arm/mach-imx/mm-imx5.c | 20 +---------
>> arch/arm/mach-imx/pm-imx5.c | 63 ++++++++++++++++++-------------
>> arch/arm/plat-mxc/include/mach/common.h | 3 +-
>> 3 files changed, 40 insertions(+), 46 deletions(-)
>>
>> diff --git a/arch/arm/mach-imx/mm-imx5.c b/arch/arm/mach-imx/mm-imx5.c
>> index d6b7e9f..bb38747 100644
>> --- a/arch/arm/mach-imx/mm-imx5.c
>> +++ b/arch/arm/mach-imx/mm-imx5.c
>> @@ -15,7 +15,6 @@
>> #include <linux/init.h>
>> #include <linux/clk.h>
>>
>> -#include <asm/system_misc.h>
>> #include <asm/mach/map.h>
>>
>> #include <mach/hardware.h>
>> @@ -23,23 +22,6 @@
>> #include <mach/devices-common.h>
>> #include <mach/iomux-v3.h>
>>
>> -static struct clk *gpc_dvfs_clk;
>> -
>> -static void imx5_idle(void)
>> -{
>> - /* gpc clock is needed for SRPG */
>> - if (gpc_dvfs_clk == NULL) {
>> - gpc_dvfs_clk = clk_get(NULL, "gpc_dvfs");
>> - if (IS_ERR(gpc_dvfs_clk))
>> - return;
>> - }
>> - clk_enable(gpc_dvfs_clk);
>> - mx5_cpu_lp_set(WAIT_UNCLOCKED_POWER_OFF);
>> - if (!tzic_enable_wake())
>> - cpu_do_idle();
>> - clk_disable(gpc_dvfs_clk);
>> -}
>> -
>> /*
>> * Define the MX50 memory map.
>> */
>> @@ -103,7 +85,6 @@ void __init imx51_init_early(void)
>> mxc_set_cpu_type(MXC_CPU_MX51);
>> mxc_iomux_v3_init(MX51_IO_ADDRESS(MX51_IOMUXC_BASE_ADDR));
>> mxc_arch_reset_init(MX51_IO_ADDRESS(MX51_WDOG1_BASE_ADDR));
>> - arm_pm_idle = imx5_idle;
>> }
>>
>> void __init imx53_init_early(void)
>> @@ -238,4 +219,5 @@ void __init imx53_soc_init(void)
>> void __init imx51_init_late(void)
>> {
>> mx51_neon_fixup();
>> + imx5_pm_init();
>> }
>> diff --git a/arch/arm/mach-imx/pm-imx5.c b/arch/arm/mach-imx/pm-imx5.c
>> index e26a9cb..6e62d79 100644
>> --- a/arch/arm/mach-imx/pm-imx5.c
>> +++ b/arch/arm/mach-imx/pm-imx5.c
>> @@ -13,18 +13,27 @@
>> #include <linux/io.h>
>> #include <linux/err.h>
>> #include <asm/cacheflush.h>
>> +#include <asm/system_misc.h>
>> #include <asm/tlbflush.h>
>> #include <mach/common.h>
>> #include <mach/hardware.h>
>> #include "crm-regs-imx5.h"
>>
>> -static struct clk *gpc_dvfs_clk;
>> +/*
>> + * The WAIT_UNCLOCKED_POWER_OFF state only requires <= 500ns to exit.
>> + * This is also the lowest power state possible without affecting
>> + * non-cpu parts of the system. For these reasons, imx5 should default
>> + * to always using this state for cpu idling. The PM_SUSPEND_STANDBY also
>> + * uses this state and needs to take no action when registers remain confgiured
>> + * for this state.
>> + */
>> +#define IMX5_DEFAULT_CPU_IDLE_STATE WAIT_UNCLOCKED_POWER_OFF
>>
>> /*
>> * set cpu low power mode before WFI instruction. This function is called
>> * mx5 because it can be used for mx50, mx51, and mx53.
>> */
>> -void mx5_cpu_lp_set(enum mxc_cpu_pwr_mode mode)
>> +static void mx5_cpu_lp_set(enum mxc_cpu_pwr_mode mode)
>> {
>> u32 plat_lpc, arm_srpgcr, ccm_clpcr;
>> u32 empgc0, empgc1;
>> @@ -87,11 +96,6 @@ void mx5_cpu_lp_set(enum mxc_cpu_pwr_mode mode)
>> }
>> }
>>
>> -static int mx5_suspend_prepare(void)
>> -{
>> - return clk_prepare_enable(gpc_dvfs_clk);
>> -}
>> -
>> static int mx5_suspend_enter(suspend_state_t state)
>> {
>> switch (state) {
>> @@ -99,7 +103,7 @@ static int mx5_suspend_enter(suspend_state_t state)
>> mx5_cpu_lp_set(STOP_POWER_OFF);
>> break;
>> case PM_SUSPEND_STANDBY:
>> - mx5_cpu_lp_set(WAIT_UNCLOCKED_POWER_OFF);
>> + /* DEFAULT_IDLE_STATE already configured */
>> break;
>> default:
>> return -EINVAL;
>> @@ -114,12 +118,10 @@ static int mx5_suspend_enter(suspend_state_t state)
>> __raw_writel(0, MXC_SRPG_EMPGC1_SRPGCR);
>> }
>> cpu_do_idle();
>> - return 0;
>> -}
>>
>> -static void mx5_suspend_finish(void)
>> -{
>> - clk_disable_unprepare(gpc_dvfs_clk);
>> + /* return registers to default idle state */
>> + mx5_cpu_lp_set(IMX5_DEFAULT_CPU_IDLE_STATE);
>> + return 0;
>> }
>>
>> static int mx5_pm_valid(suspend_state_t state)
>> @@ -129,25 +131,34 @@ static int mx5_pm_valid(suspend_state_t state)
>>
>> static const struct platform_suspend_ops mx5_suspend_ops = {
>> .valid = mx5_pm_valid,
>> - .prepare = mx5_suspend_prepare,
>> .enter = mx5_suspend_enter,
>> - .finish = mx5_suspend_finish,
>> };
>>
>> -static int __init mx5_pm_init(void)
>> +static void imx5_pm_idle(void)
>> +{
>> + if (likely(!tzic_enable_wake()))
>> + cpu_do_idle();
>> +}
>> +
>> +int __init imx5_pm_init(void)
>> {
>> - if (!cpu_is_mx51() && !cpu_is_mx53())
>> - return 0;
>> + int ret;
>> + struct clk *gpc_dvfs_clk = clk_get(NULL, "gpc_dvfs");
>> +
>> + if (IS_ERR(gpc_dvfs_clk))
>> + return (int)gpc_dvfs_clk;
>
> PTR_ERR please
>
Thanks. Will fix in v5.
>> +
>> + ret = clk_enable(gpc_dvfs_clk);
>
> clk_prepare_enable
>
Thanks. Will fix in v5.
>> + if (ret)
>> + return ret;
>> +
>> + if (cpu_is_mx51())
>> + suspend_set_ops(&mx5_suspend_ops);
>
> Now this is called only in i.MX51 context, so you can skip the cpu_is
>
After this patch series this is also called in i.MX53 context. I'm
not confident about the i.MX53 suspend/resume and would prefer to
perform further testing and address issues with it in a separate patch
series.
>>
>> - if (gpc_dvfs_clk == NULL)
>> - gpc_dvfs_clk = clk_get(NULL, "gpc_dvfs");
>> + arm_pm_idle = imx5_pm_idle;
>>
>> - if (!IS_ERR(gpc_dvfs_clk)) {
>> - if (cpu_is_mx51())
>> - suspend_set_ops(&mx5_suspend_ops);
>> - } else
>> - return -EPERM;
>> + /* Set the registers to the default cpu idle state. */
>> + mx5_cpu_lp_set(IMX5_DEFAULT_CPU_IDLE_STATE);
>>
>> return 0;
>> }
>> -device_initcall(mx5_pm_init);
>> diff --git a/arch/arm/plat-mxc/include/mach/common.h b/arch/arm/plat-mxc/include/mach/common.h
>> index cf663d8..5660e1e 100644
>> --- a/arch/arm/plat-mxc/include/mach/common.h
>> +++ b/arch/arm/plat-mxc/include/mach/common.h
>> @@ -95,7 +95,6 @@ enum mx3_cpu_pwr_mode {
>> };
>>
>> extern void mx3_cpu_lp_set(enum mx3_cpu_pwr_mode mode);
>> -extern void mx5_cpu_lp_set(enum mxc_cpu_pwr_mode mode);
>> extern void imx_print_silicon_rev(const char *cpu, int srev);
>>
>> void avic_handle_irq(struct pt_regs *);
>> @@ -146,8 +145,10 @@ extern void imx6q_clock_map_io(void);
>>
>> #ifdef CONFIG_PM
>> extern void imx6q_pm_init(void);
>> +extern int imx5_pm_init(void);
>> #else
>> static inline void imx6q_pm_init(void) {}
>> +static inline int imx5_pm_init(void) { return -ENODEV; }
>
> Why not make it return void like imx6? We do not check the return value
> anyway.
Will change in v5.
Thanks,
Rob
>
> Sascha
>
>
> --
> Pengutronix e.K. | |
> Industrial Linux Solutions | http://www.pengutronix.de/ |
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