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Message-ID: <20150123103006.GH19922@piout.net>
Date: Fri, 23 Jan 2015 11:30:06 +0100
From: Alexandre Belloni <alexandre.belloni@...e-electrons.com>
To: Wenyou Yang <wenyou.yang@...el.com>
Cc: nicolas.ferre@...el.com, linux@....linux.org.uk,
linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org,
sylvain.rochet@...secur.com, peda@...ntia.se
Subject: Re: [PATCH 07/12] pm: at91: the standby mode uses the same sram
function as the suspend to memory mode
On 20/01/2015 at 16:17:00 +0800, Wenyou Yang wrote :
> To simply the PM code, the suspend to standby mode uses the same sram function
> as the suspend to memory mode, running in the internal SRAM,
> instead of the respective code for each mode.
>
> But for the suspend to standby mode, the master clock doesn't
> switch to the slow clock, and the main oscillator doesn't
> turn off as well.
>
> Signed-off-by: Wenyou Yang <wenyou.yang@...el.com>
That looks quite better, thanks.
Acked-by: Alexandre Belloni <alexandre.belloni@...e-electrons.com>
> ---
> arch/arm/mach-at91/pm.c | 81 ++++++++++++++++---------------------
> arch/arm/mach-at91/pm.h | 6 +++
> arch/arm/mach-at91/pm_slowclock.S | 18 +++++++++
> 3 files changed, 59 insertions(+), 46 deletions(-)
>
> diff --git a/arch/arm/mach-at91/pm.c b/arch/arm/mach-at91/pm.c
> index 691e6db..a1010f0 100644
> --- a/arch/arm/mach-at91/pm.c
> +++ b/arch/arm/mach-at91/pm.c
> @@ -145,62 +145,51 @@ extern void at91_slow_clock(void __iomem *pmc, void __iomem *ramc0,
> void __iomem *ramc1, int memctrl);
> extern u32 at91_slow_clock_sz;
>
> +static void at91_pm_suspend(suspend_state_t state)
> +{
> + unsigned int pm_data = at91_pm_data.memctrl;
> +
> + pm_data |= (state == PM_SUSPEND_MEM) ?
> + (AT91_PM_SLOW_CLOCK << AT91_PM_MODE_OFFSET) : 0;
> +
> + slow_clock(at91_pmc_base, at91_ramc_base[0],
> + at91_ramc_base[1], pm_data);
> +}
> +
> static int at91_pm_enter(suspend_state_t state)
> {
> at91_pinctrl_gpio_suspend();
>
> switch (state) {
> + /*
> + * Suspend-to-RAM is like STANDBY plus slow clock mode, so
> + * drivers must suspend more deeply, the master clock switches
> + * to the clk32k and turns off the main oscillator
> + *
> + * STANDBY mode has *all* drivers suspended; ignores irqs not
> + * marked as 'wakeup' event sources; and reduces DRAM power.
> + * But otherwise it's identical to PM_SUSPEND_ON: cpu idle, and
> + * nothing fancy done with main or cpu clocks.
> + */
> + case PM_SUSPEND_MEM:
> + case PM_SUSPEND_STANDBY:
> /*
> - * Suspend-to-RAM is like STANDBY plus slow clock mode, so
> - * drivers must suspend more deeply: only the master clock
> - * controller may be using the main oscillator.
> + * Ensure that clocks are in a valid state.
> */
> - case PM_SUSPEND_MEM:
> - /*
> - * Ensure that clocks are in a valid state.
> - */
> - if (!at91_pm_verify_clocks())
> - goto error;
> -
> - /*
> - * Enter slow clock mode by switching over to clk32k and
> - * turning off the main oscillator; reverse on wakeup.
> - */
> - if (slow_clock) {
> - slow_clock(at91_pmc_base, at91_ramc_base[0],
> - at91_ramc_base[1],
> - at91_pm_data.memctrl);
> - break;
> - } else {
> - pr_info("AT91: PM - no slow clock mode enabled ...\n");
> - /* FALLTHROUGH leaving master clock alone */
> - }
> + if (!at91_pm_verify_clocks())
> + goto error;
>
> - /*
> - * STANDBY mode has *all* drivers suspended; ignores irqs not
> - * marked as 'wakeup' event sources; and reduces DRAM power.
> - * But otherwise it's identical to PM_SUSPEND_ON: cpu idle, and
> - * nothing fancy done with main or cpu clocks.
> - */
> - case PM_SUSPEND_STANDBY:
> - /*
> - * NOTE: the Wait-for-Interrupt instruction needs to be
> - * in icache so no SDRAM accesses are needed until the
> - * wakeup IRQ occurs and self-refresh is terminated.
> - * For ARM 926 based chips, this requirement is weaker
> - * as at91sam9 can access a RAM in self-refresh mode.
> - */
> - if (at91_pm_standby)
> - at91_pm_standby();
> - break;
> + at91_pm_suspend(state);
>
> - case PM_SUSPEND_ON:
> - cpu_do_idle();
> - break;
> + break;
>
> - default:
> - pr_debug("AT91: PM - bogus suspend state %d\n", state);
> - goto error;
> + case PM_SUSPEND_ON:
> + cpu_do_idle();
> + break;
> +
> + default:
> + pr_debug("AT91: PM - bogus suspend state %d\n", state);
> + goto error;
> }
>
> error:
> diff --git a/arch/arm/mach-at91/pm.h b/arch/arm/mach-at91/pm.h
> index 7664d39..fbfea42 100644
> --- a/arch/arm/mach-at91/pm.h
> +++ b/arch/arm/mach-at91/pm.h
> @@ -15,6 +15,12 @@
>
> #include <mach/at91_ramc.h>
>
> +#define AT91_PM_MEMCTRL_MASK 0x0f
> +#define AT91_PM_MODE_OFFSET 4
> +#define AT91_PM_MODE_MASK 0x0f
> +
> +#define AT91_PM_SLOW_CLOCK 0x01
> +
> /*
> * On all at91 except rm9200 and x40 have the System Controller starts
> * at address 0xffffc000 and has a size of 16KiB.
> diff --git a/arch/arm/mach-at91/pm_slowclock.S b/arch/arm/mach-at91/pm_slowclock.S
> index 634d819..92d7e63 100644
> --- a/arch/arm/mach-at91/pm_slowclock.S
> +++ b/arch/arm/mach-at91/pm_slowclock.S
> @@ -15,12 +15,15 @@
> #include <linux/clk/at91_pmc.h>
> #include <mach/at91_ramc.h>
>
> +#include "pm.h"
> +
> pmc .req r0
> sdramc .req r1
> ramc1 .req r2
> memctrl .req r3
> tmp1 .req r4
> tmp2 .req r5
> +mode .req r6
>
> /*
> * Wait until master clock is ready (after switching master clock source)
> @@ -72,6 +75,13 @@ ENTRY(at91_slow_clock)
> mov tmp1, #0
> mcr p15, 0, tmp1, c7, c10, 4
>
> + mov tmp1, memctrl
> + mov tmp2, tmp1, lsr#AT91_PM_MODE_OFFSET
> + and mode, tmp2, #AT91_PM_MODE_MASK
> +
> + mov tmp1, memctrl
> + and memctrl, tmp1, #AT91_PM_MEMCTRL_MASK
> +
> cmp memctrl, #AT91_MEMCTRL_MC
> bne ddr_sr_enable
>
> @@ -144,6 +154,9 @@ sdr_sr_enable:
> str tmp1, [sdramc, #AT91_SDRAMC_LPR]
>
> sdr_sr_done:
> + tst mode, #AT91_PM_SLOW_CLOCK
> + beq skip_disable_clock
> +
> /* Save Master clock setting */
> ldr tmp1, [pmc, #AT91_PMC_MCKR]
> str tmp1, .saved_mckr
> @@ -169,9 +182,13 @@ sdr_sr_done:
> bic tmp1, tmp1, #AT91_PMC_MOSCEN
> str tmp1, [pmc, #AT91_CKGR_MOR]
>
> +skip_disable_clock:
> /* Wait for interrupt */
> mcr p15, 0, tmp1, c7, c0, 4
>
> + tst mode, #AT91_PM_SLOW_CLOCK
> + beq skip_enable_clock
> +
> /* Turn on the main oscillator */
> ldr tmp1, [pmc, #AT91_CKGR_MOR]
> orr tmp1, tmp1, #AT91_PMC_MOSCEN
> @@ -199,6 +216,7 @@ sdr_sr_done:
>
> wait_mckrdy
>
> +skip_enable_clock:
> /*
> * at91rm9200 Memory controller
> * Do nothing - self-refresh is automatically disabled.
> --
> 1.7.9.5
>
--
Alexandre Belloni, Free Electrons
Embedded Linux, Kernel and Android engineering
http://free-electrons.com
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