Re: [PATCH 2/3] ARM: at91: pm: add per soc validation of pm modes

[<Claudiu.Beznea@microchip.com>]

On 03.08.2020 11:34, Alexandre Belloni wrote:
> EXTERNAL EMAIL: Do not click links or open attachments unless you know the content is safe
> 
> On 03/08/2020 10:25:16+0300, Claudiu Beznea wrote:
>> Not all SoCs supports all the PM mode. User may end up settings,
>> e.g. backup mode, on a non SAMA5D2 device, but the mode to not be valid.
>> If backup mode is used on a devices not supporting it there will be no
>> way of resuming other than rebooting.
> 
> I don't think this actually happens as if backup mode is requested on a
> non sama5d2 device, of_find_compatible_node(NULL, NULL,
> "atmel,sama5d2-sfrbu") will fail and the PM will default to
> AT91_PM_ULP0.

of_find_compatible_node(NULL, NULL, "atmel,sama5d2-sfrbu") is called by
at91_pm_backup_init() which is called by at91_pm_modes_init() which is
called only by sam9x60_pm_init() and sama5d2_pm_init(). Same thing with
shutdown controller compatibles. Concluding, backup could be requested for
SoCs calling:
- at91rm9200_pm_init()
- at91sam9_pm_init()
- sama5_pm_init()

The other solution for this would be to call at91_pm_modes_init() also in
the functions above. I choose the approach in this patch to avoid tracking
the dependency b/w compatibles and supported modes.

Let me know what would you prefer as a solution.

> 
> ULP1 will also default to ULP0 if the shdwc is not from sama5d2 or
> sam9x60.>
> I'm guessing the actual issue is introduced with ulp0 fast.
> 
>>
>> Signed-off-by: Claudiu Beznea <claudiu.beznea@microchip.com>
>> ---
>>  arch/arm/mach-at91/at91rm9200.c | 10 +++++-
>>  arch/arm/mach-at91/at91sam9.c   |  9 +++++-
>>  arch/arm/mach-at91/generic.h    | 20 ++++++------
>>  arch/arm/mach-at91/pm.c         | 69 +++++++++++++++++++++++++++++++++++++----
>>  arch/arm/mach-at91/sam9x60.c    | 11 ++++++-
>>  arch/arm/mach-at91/sama5.c      | 21 +++++++++++--
>>  6 files changed, 119 insertions(+), 21 deletions(-)
>>
>> diff --git a/arch/arm/mach-at91/at91rm9200.c b/arch/arm/mach-at91/at91rm9200.c
>> index 4f8186211619..7318d8e16797 100644
>> --- a/arch/arm/mach-at91/at91rm9200.c
>> +++ b/arch/arm/mach-at91/at91rm9200.c
>> @@ -13,12 +13,20 @@
>>  #include <asm/mach/arch.h>
>>
>>  #include "generic.h"
>> +#include "pm.h"
>> +
>> +/* AT91RM9200 valid PM modes. */
>> +static const int at91rm9200_pm_modes[] = {
>> +     AT91_PM_STANDBY,
>> +     AT91_PM_ULP0,
>> +};
>>
>>  static void __init at91rm9200_dt_device_init(void)
>>  {
>>       of_platform_default_populate(NULL, NULL, NULL);
>>
>> -     at91rm9200_pm_init();
>> +     at91rm9200_pm_init(at91rm9200_pm_modes,
>> +                        ARRAY_SIZE(at91rm9200_pm_modes));
>>  }
>>
> 
> You can avoid the changes in the soc files and leave everything
> contained in pm.c as each <soc>_pm_init has a known list of mode that
> will very likely never change. Bonus points if you make the arrays
> __initdata.

That was my initial approach. I went with the one in this patch to avoid
adding yet another struct of_device_id array in pm.c and keep code in pm.c
somehow platform independent. If you feel is better your way, then OK, I
have no problems with moving it in pm.c.

> 
>>  static const char *const at91rm9200_dt_board_compat[] __initconst = {
>> diff --git a/arch/arm/mach-at91/at91sam9.c b/arch/arm/mach-at91/at91sam9.c
>> index 7e572189a5eb..683f2c35a116 100644
>> --- a/arch/arm/mach-at91/at91sam9.c
>> +++ b/arch/arm/mach-at91/at91sam9.c
>> @@ -13,12 +13,19 @@
>>  #include <asm/system_misc.h>
>>
>>  #include "generic.h"
>> +#include "pm.h"
>> +
>> +/* AT91SAM9 valid PM modes. */
>> +static const int at91sam9_pm_modes[] = {
>> +     AT91_PM_STANDBY,
>> +     AT91_PM_ULP0,
>> +};
>>
>>  static void __init at91sam9_init(void)
>>  {
>>       of_platform_default_populate(NULL, NULL, NULL);
>>
>> -     at91sam9_pm_init();
>> +     at91sam9_pm_init(at91sam9_pm_modes, ARRAY_SIZE(at91sam9_pm_modes));
>>  }
>>
>>  static const char *const at91_dt_board_compat[] __initconst = {
>> diff --git a/arch/arm/mach-at91/generic.h b/arch/arm/mach-at91/generic.h
>> index 0a4cdcb4985b..610a12e5a71c 100644
>> --- a/arch/arm/mach-at91/generic.h
>> +++ b/arch/arm/mach-at91/generic.h
>> @@ -9,17 +9,17 @@
>>  #define _AT91_GENERIC_H
>>
>>  #ifdef CONFIG_PM
>> -extern void __init at91rm9200_pm_init(void);
>> -extern void __init at91sam9_pm_init(void);
>> -extern void __init sam9x60_pm_init(void);
>> -extern void __init sama5_pm_init(void);
>> -extern void __init sama5d2_pm_init(void);
>> +extern void __init at91rm9200_pm_init(const int *modes, int len);
>> +extern void __init at91sam9_pm_init(const int *modes, int len);
>> +extern void __init sam9x60_pm_init(const int *modes, int len);
>> +extern void __init sama5_pm_init(const int *modes, int len);
>> +extern void __init sama5d2_pm_init(const int *modes, int len);
>>  #else
>> -static inline void __init at91rm9200_pm_init(void) { }
>> -static inline void __init at91sam9_pm_init(void) { }
>> -static inline void __init sam9x60_pm_init(void) { }
>> -static inline void __init sama5_pm_init(void) { }
>> -static inline void __init sama5d2_pm_init(void) { }
>> +static inline void __init at91rm9200_pm_init(const int *modes, int len) { }
>> +static inline void __init at91sam9_pm_init(const int *modes, int len) { }
>> +static inline void __init sam9x60_pm_init(const int *modes, int len) { }
>> +static inline void __init sama5_pm_init(const int *modes, int len) { }
>> +static inline void __init sama5d2_pm_init(const int *modes, int len) { }
>>  #endif
>>
> 
> Then this change is not necessary.
> 
>>  #endif /* _AT91_GENERIC_H */
>> diff --git a/arch/arm/mach-at91/pm.c b/arch/arm/mach-at91/pm.c
>> index 04fdcbd57100..caf87efc7eeb 100644
>> --- a/arch/arm/mach-at91/pm.c
>> +++ b/arch/arm/mach-at91/pm.c
>> @@ -785,6 +785,59 @@ static const struct of_device_id atmel_pmc_ids[] __initconst = {
>>       { /* sentinel */ },
>>  };
>>
>> +static void __init at91_pm_modes_validate(const int *modes, int len)
>> +{
>> +     u8 i, located = 0;
>> +     int mode;
>> +
>> +#define STANDBY      BIT(0)
>> +#define SUSPEND      BIT(1)
>> +
>> +     for (i = 0; i < len; i++) {
>> +             if ((located & STANDBY) && (located & SUSPEND))
>> +                     break;
>> +
>> +             if (modes[i] == soc_pm.data.standby_mode &&
>> +                 !(located & STANDBY)) {
>> +                     located |= STANDBY;
>> +                     continue;
>> +             }
>> +
>> +             if (modes[i] == soc_pm.data.suspend_mode &&
>> +                 !(located & SUSPEND)) {
>> +                     located |= SUSPEND;
>> +                     continue;
>> +             }
>> +     }
>> +
>> +     if (!(located & STANDBY)) {
>> +             if (soc_pm.data.suspend_mode == AT91_PM_STANDBY)
>> +                     mode = AT91_PM_ULP0;
>> +             else
>> +                     mode = AT91_PM_STANDBY;
>> +
>> +             pr_warn("AT91: PM: %s mode not supported! Using %s.\n",
>> +                     pm_modes[soc_pm.data.standby_mode].pattern,
>> +                     pm_modes[mode].pattern);
>> +             soc_pm.data.standby_mode = mode;
>> +     }
>> +
>> +     if (!(located & SUSPEND)) {
>> +             if (soc_pm.data.standby_mode == AT91_PM_ULP0)
>> +                     mode = AT91_PM_STANDBY;
>> +             else
>> +                     mode = AT91_PM_ULP0;
>> +
>> +             pr_warn("AT91: PM: %s mode not supported! Using %s.\n",
>> +                     pm_modes[soc_pm.data.suspend_mode].pattern,
>> +                     pm_modes[mode].pattern);
>> +             soc_pm.data.suspend_mode = mode;
>> +     }
>> +
>> +#undef STANDBY
>> +#undef SUSPEND
> 
> You should use two booleans instead of a bit array, this would not make
> the code longer and will avoid this #def/#undef thing.

OK, I have no strong opinion on this. I'll switch to booleans.

> 
>> +}
>> +
>>  static void __init at91_pm_init(void (*pm_idle)(void))
>>  {
>>       struct device_node *pmc_np;
>> @@ -821,11 +874,12 @@ static void __init at91_pm_init(void (*pm_idle)(void))
>>       }
>>  }
>>
>> -void __init at91rm9200_pm_init(void)
>> +void __init at91rm9200_pm_init(const int *modes, int len)
>>  {
>>       if (!IS_ENABLED(CONFIG_SOC_AT91RM9200))
>>               return;
>>
>> +     at91_pm_modes_validate(modes, len);
>>       at91_dt_ramc();
>>
>>       /*
>> @@ -836,11 +890,12 @@ void __init at91rm9200_pm_init(void)
>>       at91_pm_init(at91rm9200_idle);
>>  }
>>
>> -void __init sam9x60_pm_init(void)
>> +void __init sam9x60_pm_init(const int *modes, int len)
>>  {
>>       if (!IS_ENABLED(CONFIG_SOC_SAM9X60))
>>               return;
>>
>> +     at91_pm_modes_validate(modes, len);
>>       at91_pm_modes_init();
>>       at91_dt_ramc();
>>       at91_pm_init(at91sam9x60_idle);
>> @@ -849,31 +904,33 @@ void __init sam9x60_pm_init(void)
>>       soc_pm.config_pmc_ws = at91_sam9x60_config_pmc_ws;
>>  }
>>
>> -void __init at91sam9_pm_init(void)
>> +void __init at91sam9_pm_init(const int *modes, int len)
>>  {
>>       if (!IS_ENABLED(CONFIG_SOC_AT91SAM9))
>>               return;
>>
>> +     at91_pm_modes_validate(modes, len);
>>       at91_dt_ramc();
>>       at91_pm_init(at91sam9_idle);
>>  }
>>
>> -void __init sama5_pm_init(void)
>> +void __init sama5_pm_init(const int *modes, int len)
>>  {
>>       if (!IS_ENABLED(CONFIG_SOC_SAMA5))
>>               return;
>>
>> +     at91_pm_modes_validate(modes, len);
>>       at91_dt_ramc();
>>       at91_pm_init(NULL);
>>  }
>>
>> -void __init sama5d2_pm_init(void)
>> +void __init sama5d2_pm_init(const int *modes, int len)
>>  {
>>       if (!IS_ENABLED(CONFIG_SOC_SAMA5D2))
>>               return;
>>
>> +     sama5_pm_init(modes, len);
>>       at91_pm_modes_init();
>> -     sama5_pm_init();
>>
>>       soc_pm.ws_ids = sama5d2_ws_ids;
>>       soc_pm.config_shdwc_ws = at91_sama5d2_config_shdwc_ws;
>> diff --git a/arch/arm/mach-at91/sam9x60.c b/arch/arm/mach-at91/sam9x60.c
>> index d8c739d25458..d7c869c7b542 100644
>> --- a/arch/arm/mach-at91/sam9x60.c
>> +++ b/arch/arm/mach-at91/sam9x60.c
>> @@ -14,12 +14,21 @@
>>  #include <asm/system_misc.h>
>>
>>  #include "generic.h"
>> +#include "pm.h"
>> +
>> +/* SAM9X60 valid PM modes. */
>> +static const int sam9x60_pm_modes[] = {
>> +     AT91_PM_STANDBY,
>> +     AT91_PM_ULP0,
>> +     AT91_PM_ULP0_FAST,
>> +     AT91_PM_ULP1,
>> +};
>>
>>  static void __init sam9x60_init(void)
>>  {
>>       of_platform_default_populate(NULL, NULL, NULL);
>>
>> -     sam9x60_pm_init();
>> +     sam9x60_pm_init(sam9x60_pm_modes, ARRAY_SIZE(sam9x60_pm_modes));
>>  }
>>
>>  static const char *const sam9x60_dt_board_compat[] __initconst = {
>> diff --git a/arch/arm/mach-at91/sama5.c b/arch/arm/mach-at91/sama5.c
>> index 89dab7cf01e8..7eb124612a10 100644
>> --- a/arch/arm/mach-at91/sama5.c
>> +++ b/arch/arm/mach-at91/sama5.c
>> @@ -14,11 +14,19 @@
>>  #include <asm/system_misc.h>
>>
>>  #include "generic.h"
>> +#include "pm.h"
>> +
>> +/* SAMA5 valid PM modes. */
>> +static const int sama5_pm_modes[] = {
>> +     AT91_PM_STANDBY,
>> +     AT91_PM_ULP0,
>> +     AT91_PM_ULP0_FAST,
>> +};
>>
>>  static void __init sama5_dt_device_init(void)
>>  {
>>       of_platform_default_populate(NULL, NULL, NULL);
>> -     sama5_pm_init();
>> +     sama5_pm_init(sama5_pm_modes, ARRAY_SIZE(sama5_pm_modes));
>>  }
>>
>>  static const char *const sama5_dt_board_compat[] __initconst = {
>> @@ -44,10 +52,19 @@ DT_MACHINE_START(sama5_alt_dt, "Atmel SAMA5")
>>       .l2c_aux_mask   = ~0UL,
>>  MACHINE_END
>>
>> +/* sama5d2 PM modes. */
>> +static const int sama5d2_pm_modes[] = {
>> +     AT91_PM_STANDBY,
>> +     AT91_PM_ULP0,
>> +     AT91_PM_ULP0_FAST,
>> +     AT91_PM_ULP1,
>> +     AT91_PM_BACKUP,
>> +};
>> +
>>  static void __init sama5d2_init(void)
>>  {
>>       of_platform_default_populate(NULL, NULL, NULL);
>> -     sama5d2_pm_init();
>> +     sama5d2_pm_init(sama5d2_pm_modes, ARRAY_SIZE(sama5d2_pm_modes));
>>  }
>>
>>  static const char *const sama5d2_compat[] __initconst = {
>> --
>> 2.7.4
>>
> 
> --
> Alexandre Belloni, Bootlin
> Embedded Linux and Kernel engineering
> https://bootlin.com
>