[PATCH] ux500 : decouple/recouple gic from the PRCMU

[Rickard Andersson]

Hi!

Our comments:

- function names don't match commit comment disable/enable vs recouple/decouple. Decouple is a better name than disable, because GIC is not really disabled it is just disconnected.
- there is no reason to place these functions inside the db8500-prcmu.c file. There is so much stuff in the PRCMU register base so we can not have everything in one file. Why not have it as it is?
- why the gic_mask function?
- The original code has been updated and now looks like this:


/* Decouple GIC from the interrupt bus */
void ux500_pm_gic_decouple(void)
{
         prcmu_write_masked(PRCM_A9_MASK_REQ,
                            PRCM_A9_MASK_REQ_PRCM_A9_MASK_REQ,
                            PRCM_A9_MASK_REQ_PRCM_A9_MASK_REQ);

         (void)prcmu_read(PRCM_A9_MASK_REQ);

         udelay(GIC_FREEZE_DELAY); /* Wait for the GIC to freeze */
}

/* Recouple GIC with the interrupt bus */
void ux500_pm_gic_recouple(void)
{
         prcmu_write_masked(PRCM_A9_MASK_REQ,
                            PRCM_A9_MASK_REQ_PRCM_A9_MASK_REQ,
                            0);
}

BR
Rickard Andersson&  Jonas Aberg

> This patch allows to decouple and recouple the gic from the PRCMU.
> This is needed to put the A9 core in retention mode with the cpuidle
> driver.
>
> Signed-off-by: Daniel Lezcano<daniel.lezcano at linaro.org>
> ---
>   drivers/mfd/db8500-prcmu.c       |   42 ++++++++++++++++++++++++++++++++++++++
>   include/linux/mfd/db8500-prcmu.h |    2 +
>   include/linux/mfd/dbx500-prcmu.h |   16 ++++++++++++++
>   3 files changed, 60 insertions(+), 0 deletions(-)
>
> diff --git a/drivers/mfd/db8500-prcmu.c b/drivers/mfd/db8500-prcmu.c
> index af8e0ef..c708431 100644
> --- a/drivers/mfd/db8500-prcmu.c
> +++ b/drivers/mfd/db8500-prcmu.c
> @@ -528,6 +528,10 @@ static const char *hwacc_ret_regulator_name[NUM_HW_ACC] = {
>
>   #define PRCMU_PLLDSI_LOCKP_LOCKED	0x3
>
> +#define PRCMU_A9_MASK_REQ               0x00000328
> +#define PRCMU_A9_MASK_REQ_MASK          0x00000001
> +#define PRCMU_A9_MASK_ACK               0x0000032C
> +
>   static struct {
>   	u8 project_number;
>   	u8 api_version;
> @@ -787,6 +791,44 @@ int db8500_prcmu_set_power_state(u8 state, bool keep_ulp_clk, bool keep_ap_pll)
>   	return 0;
>   }
>
> +/*
> + * prcmu_gic_mask - apply the mask to the mask request
> + * register. This mask has the bits [1-31] reserved and
> + * the request applies to the bit 0 of this register.
> + */
> +static inline void prcmu_gic_mask(u32 mask)
> +{
> +	u32 val = readl(_PRCMU_BASE + PRCMU_A9_MASK_REQ);
> +	writel((val&  ~PRCMU_A9_MASK_REQ_MASK) | mask,
> +	       _PRCMU_BASE + PRCMU_A9_MASK_REQ);
> +}
> +
> +/*
> + * db8500_prcmu_gic_disable - This function decouple the gic
> + * from the prcmu.
> + */
> +void db8500_prcmu_gic_disable(void)
> +{
> +	prcmu_gic_mask(PRCMU_A9_MASK_REQ_MASK);
> +
> +	/* Wait for gic mask register update */
> +	while (!(readl(_PRCMU_BASE + PRCMU_A9_MASK_REQ)&
> +		 PRCMU_A9_MASK_REQ_MASK))
> +		cpu_relax();
> +
> +	/* Wait a few cycles for the gic mask completion */
> +	udelay(1);
> +}
> +
> +/*
> + * db8500_prcmu_gic_enable - This function recouple the gic
> + * with the prcmu.
> + */
> +void db8500_prcmu_gic_enable(void)
> +{
> +	prcmu_gic_mask(0);
> +}
> +
>   /* This function should only be called while mb0_transfer.lock is held. */
>   static void config_wakeups(void)
>   {
> diff --git a/include/linux/mfd/db8500-prcmu.h b/include/linux/mfd/db8500-prcmu.h
> index 60d27f7..4a1032c 100644
> --- a/include/linux/mfd/db8500-prcmu.h
> +++ b/include/linux/mfd/db8500-prcmu.h
> @@ -536,6 +536,8 @@ int prcmu_load_a9wdog(u8 id, u32 val);
>
>   void db8500_prcmu_system_reset(u16 reset_code);
>   int db8500_prcmu_set_power_state(u8 state, bool keep_ulp_clk, bool keep_ap_pll);
> +void db8500_prcmu_gic_disable(void);
> +void db8500_prcmu_gic_enable(void);
>   void db8500_prcmu_enable_wakeups(u32 wakeups);
>   int db8500_prcmu_set_epod(u16 epod_id, u8 epod_state);
>   int db8500_prcmu_request_clock(u8 clock, bool enable);
> diff --git a/include/linux/mfd/dbx500-prcmu.h b/include/linux/mfd/dbx500-prcmu.h
> index bac942f..a5fee69 100644
> --- a/include/linux/mfd/dbx500-prcmu.h
> +++ b/include/linux/mfd/dbx500-prcmu.h
> @@ -237,6 +237,22 @@ static inline int prcmu_set_power_state(u8 state, bool keep_ulp_clk,
>   			keep_ap_pll);
>   }
>
> +static inline void prcmu_gic_disable(void)
> +{
> +	if (machine_is_u5500())
> +		return;
> +	else
> +		return db8500_prcmu_gic_disable();
> +}
> +
> +static inline void prcmu_gic_enable(void)
> +{
> +	if (machine_is_u5500())
> +		return;
> +	else
> +		return db8500_prcmu_gic_enable();
> +}
> +
>   static inline int prcmu_set_epod(u16 epod_id, u8 epod_state)
>   {
>   	if (machine_is_u5500())