Re: [PATCH v4 3/7] ARM: imx: clean and consolidate imx5 suspend and idle code

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@linaro.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

• ret = clk_enable(gpc_dvfs_clk);

clk_prepare_enable

• 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

• 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.

Sascha