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

Nishanth Menon
2009-10-03T14:56:26Z

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?
> +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