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....@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
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