Subject: [RFC PATCH 4/9] soc: samsung: Add generic power-management driver for Exynos

From: [email-masked] (Chanwoo Choi)
Date: Thu, 11 Jan 2018 14:44:09 +0900

Dear Krzysztof,

I'll try to consolidate the pm code for both arm and arm64.
So, drop this patch and then I'll start to move the code
from arch/arm/mach-exynos/* to drivers/soc/samsung/*.

But, I'm not sure it is possible to move all codes
to drivers/soc/samsung/*. I'll try it.

Best Regards,
Chanwoo Choi
Samsung Electronics

On 2018? 01? 09? 21:37, Krzysztof Kozlowski wrote:
> On Tue, Jan 9, 2018 at 8:59 AM, Chanwoo Choi <[email-masked]> wrote:
>> To enter suspend, Exynos SoC requires the some machine dependent procedures.
>> This patch introduces the generic power-management driver to support
>> those requirements and generic interface for power state management.
>>
>> Signed-off-by: Jonghwa Lee <[email-masked]>
>> Signed-off-by: Chanwoo Choi <[email-masked]>
>> ---
>>  arch/arm/mach-exynos/common.h         |   1 -
>>  arch/arm/mach-exynos/exynos.c         |  23 +----
>>  drivers/soc/samsung/Makefile          |   2 +-
>>  drivers/soc/samsung/exynos-pm.c       | 176 ++++++++++++++++++++++++++++++++++
>>  include/linux/soc/samsung/exynos-pm.h |  21 ++++
>>  5 files changed, 199 insertions(+), 24 deletions(-)
>>  create mode 100644 drivers/soc/samsung/exynos-pm.c
>>  create mode 100644 include/linux/soc/samsung/exynos-pm.h
>>
>> diff --git a/arch/arm/mach-exynos/common.h b/arch/arm/mach-exynos/common.h
>> index afbc143a3d5d..ad482c0fc131 100644
>> --- a/arch/arm/mach-exynos/common.h
>> +++ b/arch/arm/mach-exynos/common.h
>> @@ -119,7 +119,6 @@ enum {
>>   * Magic values for bootloader indicating chosen low power mode.
>>   * See also Documentation/arm/Samsung/Bootloader-interface.txt
>>   */
>> -#define EXYNOS_SLEEP_MAGIC     0x00000bad
>>  #define EXYNOS_AFTR_MAGIC      0xfcba0d10
>>
>>  void exynos_set_boot_flag(unsigned int cpu, unsigned int mode);
>> diff --git a/arch/arm/mach-exynos/exynos.c b/arch/arm/mach-exynos/exynos.c
>> index fbd108ce8745..0d5265d175c4 100644
>> --- a/arch/arm/mach-exynos/exynos.c
>> +++ b/arch/arm/mach-exynos/exynos.c
>> @@ -12,6 +12,7 @@
>>  #include <linux/of_fdt.h>
> 
> of_address.h might be not needed anymore.
> 
>>  #include <linux/platform_device.h>
>>  #include <linux/irqchip.h>
>> +#include <linux/soc/samsung/exynos-pm.h>
>>  #include <linux/soc/samsung/exynos-regs-pmu.h>
>>
>>  #include <asm/cacheflush.h>
>> @@ -41,28 +42,6 @@
>>         .id                = -1,
>>  };
>>
>> -void __iomem *sysram_base_addr __ro_after_init;
>> -void __iomem *sysram_ns_base_addr __ro_after_init;
>> -
>> -void __init exynos_sysram_init(void)
>> -{
>> -       struct device_node *node;
>> -
>> -       for_each_compatible_node(node, NULL, "samsung,exynos4210-sysram") {
>> -               if (!of_device_is_available(node))
>> -                       continue;
>> -               sysram_base_addr = of_iomap(node, 0);
>> -               break;
>> -       }
>> -
>> -       for_each_compatible_node(node, NULL, "samsung,exynos4210-sysram-ns") {
>> -               if (!of_device_is_available(node))
>> -                       continue;
>> -               sysram_ns_base_addr = of_iomap(node, 0);
>> -               break;
>> -       }
>> -}
>> -
>>  static void __init exynos_init_late(void)
>>  {
>>         if (of_machine_is_compatible("samsung,exynos5440"))
>> diff --git a/drivers/soc/samsung/Makefile b/drivers/soc/samsung/Makefile
>> index d2e637339a45..58ca5bdabf1f 100644
>> --- a/drivers/soc/samsung/Makefile
>> +++ b/drivers/soc/samsung/Makefile
>> @@ -1,5 +1,5 @@
>>  # SPDX-License-Identifier: GPL-2.0
>> -obj-$(CONFIG_EXYNOS_PMU)       += exynos-pmu.o
>> +obj-$(CONFIG_EXYNOS_PMU)       += exynos-pmu.o exynos-pm.o
>>
>>  obj-$(CONFIG_EXYNOS_PMU_ARM_DRIVERS)   += exynos3250-pmu.o exynos4-pmu.o \
>>                                         exynos5250-pmu.o exynos5420-pmu.o \
>> diff --git a/drivers/soc/samsung/exynos-pm.c b/drivers/soc/samsung/exynos-pm.c
>> new file mode 100644
>> index 000000000000..45d84bbe5e61
>> --- /dev/null
>> +++ b/drivers/soc/samsung/exynos-pm.c
>> @@ -0,0 +1,176 @@
>> +// SPDX-License-Identifier: GPL-2.0
>> +//
>> +// based on arch/arm/mach-exynos/suspend.c
>> +// Copyright (c) 2018 Samsung Electronics Co., Ltd.
>> +//
>> +// Exynos Power Management support driver
>> +
>> +#include <linux/of.h>
>> +#include <linux/of_address.h>
>> +#include <linux/of_fdt.h>
>> +#include <linux/kernel.h>
>> +#include <linux/regulator/machine.h>
>> +#include <linux/syscore_ops.h>
>> +#include <linux/suspend.h>
>> +
>> +#include <asm/cpuidle.h>
>> +#include <asm/io.h>
>> +#include <asm/suspend.h>
>> +
>> +#include <linux/soc/samsung/exynos-pm.h>
>> +#include <linux/soc/samsung/exynos-pmu.h>
>> +
>> +/*
>> + * The struct exynos_pm_data contains the callbacks of
>> + * both struct platform_suspend_ops and syscore_ops.
>> + * This structure is listed according to the call order,
>> + * because the callback call order for the two structures is mixed.
>> + */
>> +struct exynos_pm_data {
>> +       int (*prepare)(void);                   /* for platform_suspend_ops */
>> +       int (*suspend)(void);                   /* for syscore_ops */
>> +       int (*enter)(suspend_state_t state);    /* for platform_suspend_ops */
>> +       void (*resume)(void);                   /* for syscore_ops */
>> +       void (*finish)(void);                   /* for platform_suspend_ops */
>> +};
>> +
>> +static struct platform_suspend_ops exynos_pm_suspend_ops;
>> +static struct syscore_ops exynos_pm_syscore_ops;
>> +static const struct exynos_pm_data *pm_data  __ro_after_init;
> 
> It is already const, so __initconst?
> 
>> +
>> +void __iomem *sysram_base_addr __ro_after_init;
>> +void __iomem *sysram_ns_base_addr __ro_after_init;
>> +
>> +static int exynos_pm_prepare(void)
>> +{
>> +       int ret;
>> +
>> +       /*
>> +        * REVISIT: It would be better if struct platform_suspend_ops
>> +        * .prepare handler get the suspend_state_t as a parameter to
>> +        * avoid hard-coding the suspend to mem state. It's safe to do
>> +        * it now only because the suspend_valid_only_mem function is
>> +        * used as the .valid callback used to check if a given state
>> +        * is supported by the platform anyways.
>> +        */
>> +       ret = regulator_suspend_prepare(PM_SUSPEND_MEM);
>> +       if (ret) {
>> +               pr_err("Failed to prepare regulators for suspend (%d)\n", ret);
>> +               return ret;
>> +       }
>> +
>> +       if (pm_data->prepare) {
>> +               ret = pm_data->prepare();
>> +               if (ret) {
>> +                       pr_err("Failed to prepare for suspend (%d)\n", ret);
>> +                       return ret;
>> +               }
>> +       }
>> +
>> +       return 0;
>> +}
>> +
>> +static int exynos_pm_suspend(void)
>> +{
>> +       if (pm_data->suspend)
>> +               return pm_data->suspend();
>> +
>> +       return 0;
>> +}
>> +
>> +static int exynos_pm_enter(suspend_state_t state)
>> +{
>> +       int ret;
>> +
>> +       exynos_sys_powerdown_conf(SYS_SLEEP);
>> +
>> +       ret = pm_data->enter(state);
>> +       if (ret) {
>> +               pr_err("Failed to enter sleep\n");
>> +               return ret;
>> +       }
>> +
>> +       return 0;
>> +}
>> +
>> +static void exynos_pm_resume(void)
>> +{
>> +       exynos_sys_powerup_conf(SYS_SLEEP);
>> +
>> +       if (pm_data->resume)
>> +               pm_data->resume();
>> +}
>> +
>> +static void exynos_pm_finish(void)
>> +{
>> +       int ret;
>> +
>> +       ret = regulator_suspend_finish();
>> +       if (ret)
>> +               pr_warn("Failed to resume regulators from suspend (%d)\n", ret);
>> +
>> +       if (pm_data->finish)
>> +               pm_data->finish();
>> +}
>> +
>> +/*
>> + * Split the data between ARM architectures because it is relatively big
>> + * and useless on other arch.
>> + */
>> +#ifdef CONFIG_EXYNOS_PMU_ARM_DRIVERS
>> +#define exynos_pm_data_arm_ptr(data)   (&data)
>> +#else
>> +#define exynos_pm_data_arm_ptr(data)   NULL
>> +#endif
>> +
>> +static const struct of_device_id exynos_pm_of_device_ids[] = {
>> +       { /*sentinel*/ },
>> +};
>> +
>> +void __init exynos_sysram_init(void)
>> +{
>> +       struct device_node *np;
>> +
>> +       for_each_compatible_node(np, NULL, "samsung,exynos4210-sysram") {
>> +               if (!of_device_is_available(np))
>> +                       continue;
>> +               sysram_base_addr = of_iomap(np, 0);
>> +               break;
>> +       }
>> +
>> +       for_each_compatible_node(np, NULL, "samsung,exynos4210-sysram-ns") {
>> +               if (!of_device_is_available(np))
>> +                       continue;
>> +               sysram_ns_base_addr = of_iomap(np, 0);
>> +               break;
>> +       }
>> +}
>> +
>> +static int __init exynos_pm_init(void)
>> +{
>> +       const struct of_device_id *match;
>> +       struct device_node *np;
>> +
>> +       np = of_find_matching_node_and_match(NULL,
>> +                                       exynos_pm_of_device_ids, &match);
>> +       if (!np) {
>> +               pr_err("Failed to find PMU node for Exynos Power-Management\n");
>> +               return -ENODEV;
>> +       }
>> +       pm_data = (const struct exynos_pm_data *) match->data;
>> +
>> +       exynos_sysram_init();
>> +
>> +       exynos_pm_suspend_ops.valid     = suspend_valid_only_mem;
>> +       exynos_pm_suspend_ops.prepare   = exynos_pm_prepare;
>> +       exynos_pm_syscore_ops.suspend   = exynos_pm_suspend;
>> +       exynos_pm_suspend_ops.enter     = exynos_pm_enter;
>> +       exynos_pm_syscore_ops.resume    = exynos_pm_resume;
>> +       exynos_pm_suspend_ops.finish    = exynos_pm_finish;
>> +
>> +       register_syscore_ops(&exynos_pm_syscore_ops);
>> +       suspend_set_ops(&exynos_pm_suspend_ops);
>> +
>> +       return 0;
>> +}
>> +postcore_initcall(exynos_pm_init);
> 
> As I mentioned in cover letter, please move here first ARMv7 code. Now
> it looks like duplicating the existing code.
> 
>> diff --git a/include/linux/soc/samsung/exynos-pm.h b/include/linux/soc/samsung/exynos-pm.h
>> new file mode 100644
>> index 000000000000..b1afe95ed10c
>> --- /dev/null
>> +++ b/include/linux/soc/samsung/exynos-pm.h
>> @@ -0,0 +1,21 @@
>> +// SPDX-License-Identifier: GPL-2.0
>> +//
>> +// Copyright (c) 2018 Samsung Electronics Co., Ltd.
>> +//
>> +// Header for Exynos Power-Management support driver
> 
> Use header-style SPDX and comment.
> 
> Best regards,
> Krzysztof
> 
>> +
>> +#ifndef __LINUX_SOC_EXYNOS_PM_H
>> +#define __LINUX_SOC_EXYNOS_PM_H
>> +
>> +/*
>> + * Magic values for bootloader indicating chosen low power mode.
>> + * See also Documentation/arm/Samsung/Bootloader-interface.txt
>> + */
>> +#define EXYNOS_SLEEP_MAGIC     0x00000bad
>> +
>> +extern void __iomem *sysram_base_addr;
>> +extern void __iomem *sysram_ns_base_addr;
> 
> Since these are now global symbols, they need nice exynos prefix.
> Also, probably they should not be globally modifiable. Only
> exynos_sysram_init() should write there. Instead export a global
> accessor (get()) and rest should use that one.
> 
> Best regards,
> Krzysztof
> 
>> +
>> +extern void exynos_sysram_init(void);
>> +
>> +#endif /* __LINUX_SOC_EXYNOS_PMU_H */
>> --
>> 1.9.1
>>
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