[V5,16/18] soc/tegra: pmc: Configure deep sleep control settings

Tegra210 and prior Tegra chips have deep sleep entry and wakeup related
timings which are platform specific that should be configured before
entering into deep sleep.

Below are the timing specific configurations for deep sleep entry and
wakeup.
- Core rail power-on stabilization timer
- OSC clock stabilization timer after SOC rail power is stabilized.
- Core power off time is the minimum wake delay to keep the system
  in deep sleep state irrespective of any quick wake event.

These values depends on the discharge time of regulators and turn OFF
time of the PMIC to allow the complete system to finish entering into
deep sleep state.

These values vary based on the platform design and are specified
through the device tree.

This patch has implementation to configure these timings which are must
to have for proper deep sleep and wakeup operations.

Signed-off-by: Sowjanya Komatineni <skomatineni@nvidia.com>
---
 drivers/soc/tegra/pmc.c | 12 ++++++++++++
 1 file changed, 12 insertions(+)

28.06.2019 5:12, Sowjanya Komatineni пишет:
> Tegra210 and prior Tegra chips have deep sleep entry and wakeup related
> timings which are platform specific that should be configured before
> entering into deep sleep.
> 
> Below are the timing specific configurations for deep sleep entry and
> wakeup.
> - Core rail power-on stabilization timer
> - OSC clock stabilization timer after SOC rail power is stabilized.
> - Core power off time is the minimum wake delay to keep the system
>   in deep sleep state irrespective of any quick wake event.
> 
> These values depends on the discharge time of regulators and turn OFF
> time of the PMIC to allow the complete system to finish entering into
> deep sleep state.
> 
> These values vary based on the platform design and are specified
> through the device tree.
> 
> This patch has implementation to configure these timings which are must
> to have for proper deep sleep and wakeup operations.
> 
> Signed-off-by: Sowjanya Komatineni <skomatineni@nvidia.com>
> ---
>  drivers/soc/tegra/pmc.c | 12 ++++++++++++
>  1 file changed, 12 insertions(+)
> 
> diff --git a/drivers/soc/tegra/pmc.c b/drivers/soc/tegra/pmc.c
> index ed83c0cd09a3..7e4a8f04f4c4 100644
> --- a/drivers/soc/tegra/pmc.c
> +++ b/drivers/soc/tegra/pmc.c
> @@ -89,6 +89,8 @@
>  
>  #define PMC_CPUPWRGOOD_TIMER		0xc8
>  #define PMC_CPUPWROFF_TIMER		0xcc
> +#define PMC_COREPWRGOOD_TIMER		0x3c
> +#define PMC_COREPWROFF_TIMER		0xe0
>  
>  #define PMC_PWR_DET_VALUE		0xe4
>  
> @@ -2291,6 +2293,7 @@ static const struct tegra_pmc_regs tegra20_pmc_regs = {
>  static void tegra20_pmc_init(struct tegra_pmc *pmc)
>  {
>  	u32 value;
> +	unsigned long osc, pmu, off;
>  
>  	/* Always enable CPU power request */
>  	value = tegra_pmc_readl(pmc, PMC_CNTRL);
> @@ -2316,6 +2319,15 @@ static void tegra20_pmc_init(struct tegra_pmc *pmc)
>  	value = tegra_pmc_readl(pmc, PMC_CNTRL);
>  	value |= PMC_CNTRL_SYSCLK_OE;
>  	tegra_pmc_writel(pmc, value, PMC_CNTRL);
> +
> +	osc = DIV_ROUND_UP_ULL(pmc->core_osc_time * 8192, 1000000);
> +	pmu = DIV_ROUND_UP_ULL(pmc->core_pmu_time * 32768, 1000000);
> +	off = DIV_ROUND_UP_ULL(pmc->core_off_time * 32768, 1000000);

IIUC, the first argument shall be explicitly of a type "long long", shouldn't it?
Otherwise the multiplication will overflow before division happens.

Thus:

	osc = DIV_ROUND_UP_ULL((u64)pmc->core_osc_time * 8192, 1000000);
	pmu = DIV_ROUND_UP_ULL((u64)pmc->core_pmu_time * 32768, 1000000);
	off = DIV_ROUND_UP_ULL((u64)pmc->core_off_time * 32768, 1000000);

Also, could you please tell what of the above multiplications could overflow u32 in
the first place? Maybe DIV_ROUND_UP_ULL isn't needed at all and DIV_ROUND_UP could be
use instead?

28.06.2019 5:12, Sowjanya Komatineni пишет:
> Tegra210 and prior Tegra chips have deep sleep entry and wakeup related
> timings which are platform specific that should be configured before
> entering into deep sleep.
> 
> Below are the timing specific configurations for deep sleep entry and
> wakeup.
> - Core rail power-on stabilization timer
> - OSC clock stabilization timer after SOC rail power is stabilized.
> - Core power off time is the minimum wake delay to keep the system
>   in deep sleep state irrespective of any quick wake event.
> 
> These values depends on the discharge time of regulators and turn OFF
> time of the PMIC to allow the complete system to finish entering into
> deep sleep state.
> 
> These values vary based on the platform design and are specified
> through the device tree.
> 
> This patch has implementation to configure these timings which are must
> to have for proper deep sleep and wakeup operations.
> 
> Signed-off-by: Sowjanya Komatineni <skomatineni@nvidia.com>
> ---
>  drivers/soc/tegra/pmc.c | 12 ++++++++++++
>  1 file changed, 12 insertions(+)
> 
> diff --git a/drivers/soc/tegra/pmc.c b/drivers/soc/tegra/pmc.c
> index ed83c0cd09a3..7e4a8f04f4c4 100644
> --- a/drivers/soc/tegra/pmc.c
> +++ b/drivers/soc/tegra/pmc.c
> @@ -89,6 +89,8 @@
>  
>  #define PMC_CPUPWRGOOD_TIMER		0xc8
>  #define PMC_CPUPWROFF_TIMER		0xcc
> +#define PMC_COREPWRGOOD_TIMER		0x3c
> +#define PMC_COREPWROFF_TIMER		0xe0
>  
>  #define PMC_PWR_DET_VALUE		0xe4
>  
> @@ -2291,6 +2293,7 @@ static const struct tegra_pmc_regs tegra20_pmc_regs = {
>  static void tegra20_pmc_init(struct tegra_pmc *pmc)
>  {
>  	u32 value;
> +	unsigned long osc, pmu, off;

I'd write this as:

 	u32 value, osc, pmu, off;

Because "unsigned long" has the same size as u32 in this case.