Re: [PATCH 01/28] OMAP3: PM: GPMC context save/restore

[Kevin Hilman <khilman@deeprootsystems.com>]

Nishanth Menon <menon.nishanth@gmail.com> writes:

> Kevin Hilman said the following on 10/01/2009 06:58 PM:
>> From: Rajendra Nayak <rnayak@ti.com>
>>
>> This patch adds the context save restore functions for GPMC
>>
>> Signed-off-by: Rajendra Nayak <rnayak@ti.com>
>> ---
>>  arch/arm/mach-omap2/gpmc.c             |   93 ++++++++++++++++++++++++++++++++
>>  arch/arm/plat-omap/include/mach/gpmc.h |    3 +
>>  2 files changed, 96 insertions(+), 0 deletions(-)
>>
>> diff --git a/arch/arm/mach-omap2/gpmc.c b/arch/arm/mach-omap2/gpmc.c
>> index 1587682..86ea936 100644
>> --- a/arch/arm/mach-omap2/gpmc.c
>> +++ b/arch/arm/mach-omap2/gpmc.c
>> @@ -62,10 +62,38 @@
>>  #define ENABLE_PREFETCH		(0x1 << 7)
>>  #define DMA_MPU_MODE		2
>>  
>> +/* Structure to save gpmc cs context */
>> +struct gpmc_cs_config {
>> +	u32 config1;
>> +	u32 config2;
>> +	u32 config3;
>> +	u32 config4;
>> +	u32 config5;
>> +	u32 config6;
>> +	u32 config7;
>> +	int is_valid;
>> +};
>> +
>> +/*
>> + * Structure to save/restore gpmc context
>> + * to support core off on OMAP3
>> + */
>> +struct omap3_gpmc_regs {
>> +	u32 sysconfig;
>> +	u32 irqenable;
>> +	u32 timeout_ctrl;
>> +	u32 config;
>> +	u32 prefetch_config1;
>> +	u32 prefetch_config2;
>> +	u32 prefetch_control;
>> +	struct gpmc_cs_config cs_context[GPMC_CS_NUM];
>> +};
>> +
>>  static struct resource	gpmc_mem_root;
>>  static struct resource	gpmc_cs_mem[GPMC_CS_NUM];
>>  static DEFINE_SPINLOCK(gpmc_mem_lock);
>>  static unsigned		gpmc_cs_map;
>> +static struct omap3_gpmc_regs gpmc_context;
>>  
>>  static void __iomem *gpmc_base;
>>  
>> @@ -516,3 +544,68 @@ void __init gpmc_init(void)
>>  	gpmc_write_reg(GPMC_SYSCONFIG, l);
>>  	gpmc_mem_init();
>>  }
>> +
>> +#ifdef CONFIG_ARCH_OMAP3
>>   
> apologies if this is a dumb question - why is this under #ifdef -> if
> the save save restore structures are not under #ifdef?

Not a dumb question, good catch.  I'll move the struct inside
this #ifdef.

Kevin

>> +void omap3_gpmc_save_context()
>> +{
>> +	int i;
>> +	gpmc_context.sysconfig = gpmc_read_reg(GPMC_SYSCONFIG);
>> +	gpmc_context.irqenable = gpmc_read_reg(GPMC_IRQENABLE);
>> +	gpmc_context.timeout_ctrl = gpmc_read_reg(GPMC_TIMEOUT_CONTROL);
>> +	gpmc_context.config = gpmc_read_reg(GPMC_CONFIG);
>> +	gpmc_context.prefetch_config1 = gpmc_read_reg(GPMC_PREFETCH_CONFIG1);
>> +	gpmc_context.prefetch_config2 = gpmc_read_reg(GPMC_PREFETCH_CONFIG2);
>> +	gpmc_context.prefetch_control = gpmc_read_reg(GPMC_PREFETCH_CONTROL);
>> +	for (i = 0; i < GPMC_CS_NUM; i++) {
>> +		gpmc_context.cs_context[i].is_valid =
>> +				(gpmc_cs_read_reg(i, GPMC_CS_CONFIG7))
>> +							& GPMC_CONFIG7_CSVALID;
>> +		if (gpmc_context.cs_context[i].is_valid) {
>> +			gpmc_context.cs_context[i].config1 =
>> +				gpmc_cs_read_reg(i, GPMC_CS_CONFIG1);
>> +			gpmc_context.cs_context[i].config2 =
>> +				gpmc_cs_read_reg(i, GPMC_CS_CONFIG2);
>> +			gpmc_context.cs_context[i].config3 =
>> +				gpmc_cs_read_reg(i, GPMC_CS_CONFIG3);
>> +			gpmc_context.cs_context[i].config4 =
>> +				gpmc_cs_read_reg(i, GPMC_CS_CONFIG4);
>> +			gpmc_context.cs_context[i].config5 =
>> +				gpmc_cs_read_reg(i, GPMC_CS_CONFIG5);
>> +			gpmc_context.cs_context[i].config6 =
>> +				gpmc_cs_read_reg(i, GPMC_CS_CONFIG6);
>> +			gpmc_context.cs_context[i].config7 =
>> +				gpmc_cs_read_reg(i, GPMC_CS_CONFIG7);
>> +		}
>>   
> here is a theoretical bug:
> 1: GPMC, 1, 2, 3 4 5 configured 6 7 not configured.
> 2. Save and restore 1: save and restore variables which are static will
> contain 1-5 and not 6&7
> 3. next I disable 2,3
> 3. save will save 1,4,5 BUT my variable will contain 1,2,3,4,5 ->
> restore will rename 2,3 (which I did not intend)..
>
> Regards,
> Nishanth Menon