Subject: [PATCH 18/25] OMAP4: suspend: Add MPUSS power domain RETENTION support

From: [email-masked] (Santosh)
Date: Thu, 15 Sep 2011 08:49:44 +0530

On Thursday 15 September 2011 05:57 AM, Kevin Hilman wrote:
> Santosh Shilimkar <[email-masked]> writes:
> 
>> This patch adds MPUSS(MPU Sub System) power domain
>> CSWR(Close Switch Retention) support to system wide suspend.
>> For both MPUSS RET support, CPUs are programmed to OFF state.
> 
> is 'both' in the wrong place in this sentence?   I think you meant:
> 
You are right.

> For MPUSS retention support, both CPUs are programmed to OFF state.
> 
>> Signed-off-by: Santosh Shilimkar <[email-masked]>
>> Cc: Kevin Hilman <[email-masked]>
>> ---
>>  arch/arm/mach-omap2/omap-mpuss-lowpower.c |   16 +++++++
>>  arch/arm/mach-omap2/pm44xx.c              |   71 +++++++++++++++++++++++++++--
>>  2 files changed, 82 insertions(+), 5 deletions(-)
>>
>> diff --git a/arch/arm/mach-omap2/omap-mpuss-lowpower.c b/arch/arm/mach-omap2/omap-mpuss-lowpower.c
>> index 9d68abf..9f632fe 100644
>> --- a/arch/arm/mach-omap2/omap-mpuss-lowpower.c
>> +++ b/arch/arm/mach-omap2/omap-mpuss-lowpower.c
>> @@ -66,6 +66,7 @@ struct omap4_cpu_pm_info {
>>  };
>>  
>>  static DEFINE_PER_CPU(struct omap4_cpu_pm_info, omap4_pm_info);
>> +static struct powerdomain *mpuss_pd;
>>  
>>  /*
>>   * Program the wakeup routine address for the CPU0 and CPU1
>> @@ -140,6 +141,13 @@ static void scu_pwrst_prepare(unsigned int cpu_id, unsigned int cpu_state)
>>   * of OMAP4 MPUSS subsystem
>>   * @cpu : CPU ID
>>   * @power_state: Low power state.
>> + *
>> + * MPUSS states for the context save:
>> + * save_state =
>> + *	0 - Nothing lost and no need to save: MPUSS INACTIVE
>> + *	1 - CPUx L1 and logic lost: MPUSS CSWR
>> + *	2 - CPUx L1 and logic lost + GIC lost: MPUSS OSWR
>> + *	3 - CPUx L1 and logic lost + GIC + L2 lost: DEVICE OFF
>>   */
>>  int omap4_enter_lowpower(unsigned int cpu, unsigned int power_state)
>>  {
>> @@ -169,6 +177,7 @@ int omap4_enter_lowpower(unsigned int cpu, unsigned int power_state)
>>  		return -ENXIO;
>>  	}
>>  
>> +	pwrdm_clear_all_prev_pwrst(mpuss_pd);
>>  	clear_cpu_prev_pwrst(cpu);
>>  	set_cpu_next_pwrst(cpu, power_state);
>>  	set_cpu_wakeup_addr(cpu, virt_to_phys(omap4_cpu_resume));
>> @@ -270,6 +279,13 @@ int __init omap4_mpuss_init(void)
>>  	/* Initialise CPU1 power domain state to ON */
>>  	pwrdm_set_next_pwrst(pm_info->pwrdm, PWRDM_POWER_ON);
>>  
>> +	mpuss_pd = pwrdm_lookup("mpu_pwrdm");
>> +	if (!mpuss_pd) {
>> +		pr_err("Failed to lookup MPUSS power domain\n");
>> +		return -ENODEV;
>> +	}
>> +	pwrdm_clear_all_prev_pwrst(mpuss_pd);
>> +
>>  	/* Save device type on scratchpad for low level code to use */
>>  	if (omap_type() != OMAP2_DEVICE_TYPE_GP)
>>  		__raw_writel(1, sar_base + OMAP_TYPE_OFFSET);
>> diff --git a/arch/arm/mach-omap2/pm44xx.c b/arch/arm/mach-omap2/pm44xx.c
>> index 4f39de5..63e8f9b 100644
>> --- a/arch/arm/mach-omap2/pm44xx.c
>> +++ b/arch/arm/mach-omap2/pm44xx.c
>> @@ -1,8 +1,9 @@
>>  /*
>>   * OMAP4 Power Management Routines
>>   *
>> - * Copyright (C) 2010 Texas Instruments, Inc.
>> + * Copyright (C) 2010-2011 Texas Instruments, Inc.
>>   * Rajendra Nayak <[email-masked]>
>> + * Santosh Shilimkar <[email-masked]>
>>   *
>>   * This program is free software; you can redistribute it and/or modify
>>   * it under the terms of the GNU General Public License version 2 as
>> @@ -16,9 +17,11 @@
>>  #include <linux/err.h>
>>  #include <linux/slab.h>
>>  
>> +#include <mach/omap4-common.h>
>> +
>>  #include "powerdomain.h"
>>  #include "clockdomain.h"
>> -#include <mach/omap4-common.h>
>> +#include "pm.h"
>>  
>>  struct power_state {
>>  	struct powerdomain *pwrdm;
>> @@ -34,7 +37,48 @@ static LIST_HEAD(pwrst_list);
>>  #ifdef CONFIG_SUSPEND
>>  static int omap4_pm_suspend(void)
>>  {
>> -	omap_do_wfi();
>> +	struct power_state *pwrst;
>> +	int state, ret = 0;
>> +	u32 cpu_id = smp_processor_id();
>> +
>> +	/* Save current powerdomain state */
>> +	list_for_each_entry(pwrst, &pwrst_list, node) {
>> +		pwrst->saved_state = pwrdm_read_next_pwrst(pwrst->pwrdm);
>> +	}
>> +
>> +	/* Set targeted power domain states by suspend */
>> +	list_for_each_entry(pwrst, &pwrst_list, node) {
>> +		omap_set_pwrdm_state(pwrst->pwrdm, pwrst->next_state);
>> +	}
>> +
>> +	/*
>> +	 * For MPUSS to hit power domain retention(CSWR or OSWR),
>> +	 * CPU0 and CPU1 power domain needs to be in OFF or DORMANT
> 
> s/domain needs/domains need/
>
ok

>> +	 * state. For MPUSS to reach off-mode. CPU0 and CPU1 power domain
>> +	 * should be in off state.
> 
> nit: please be consistent with naming of power states (e.g. OFF vs. off)
> 
ok.

>> +	 * Only master CPU followes suspend path. All other CPUs follow
>> +	 * cpu-hotplug path in system wide suspend. On OMAP4, CPU power
>> +	 * domain CSWR is not supported by hardware.
> 
> I think this sentence belongs a little earlier.  E.g. something like
> ...CPU0 and CPU1 power domains need to be in OFF or DORMANT state, since
> CPU power domain CSWR is not supported by hardware.
>
Looks better.

>> +	 * More details can be found in OMAP4430 TRM section 4.3.4.2.
>> +	 */
>> +	omap4_enter_lowpower(cpu_id, PWRDM_POWER_OFF);
>> +
>> +	/* Restore next powerdomain state */
>> +	list_for_each_entry(pwrst, &pwrst_list, node) {
>> +		state = pwrdm_read_prev_pwrst(pwrst->pwrdm);
>> +		if (state > pwrst->next_state) {
>> +			pr_info("Powerdomain (%s) didn't enter "
>> +			       "target state %d\n",
>> +			       pwrst->pwrdm->name, pwrst->next_state);
>> +			ret = -1;
>> +		}0001
>> +		omap_set_pwrdm_state(pwrst->pwrdm, pwrst->saved_state);
>> +	}
>> +	if (ret)
>> +		pr_err("Could not enter target state in pm_suspend\n");
> 
> Without more details, this isn't terribly useful.  I'd suggest just
> making the per-state one above pr_err().
> 
You mean pr_crit ?

>> +	else
>> +		pr_err("Successfully put all powerdomains to target state\n");
> 
> and this one pr_info.
> 
>>  	return 0;
>>  }
>>  
>> @@ -97,14 +141,31 @@ static int __init pwrdms_setup(struct powerdomain *pwrdm, void *unused)
>>  	if (!pwrdm->pwrsts)
>>  		return 0;
>>  
>> +	/*
>> +	 * Skip CPU0 and CPU1 power domains. CPU1 is programmed
>> +	 * through hotplug path and CPU0 explicitly programmed
>> +	 * further down in the code path
>> +	 */
>> +	if ((!strcmp(pwrdm->name, "cpu0_pwrdm")) ||
>> +		(!strcmp(pwrdm->name, "cpu1_pwrdm")))
> 
> or just one compare using strncmp(pwrdm->name, "cpu", 3)
> 
Let me check this.

Regards
Santosh