Re: [PATCH V6 06/21] clk: tegra: pll: Save and restore pll context

[Sowjanya Komatineni <skomatineni@nvidia.com>]

On 7/21/19 2:44 PM, Dmitry Osipenko wrote:
> 21.07.2019 22:40, Sowjanya Komatineni пишет:
>> This patch implements save and restore of PLL context.
>>
>> During system suspend, core power goes off and looses the settings
>> of the Tegra CAR controller registers.
>>
>> So during suspend entry pll rate is stored and on resume it is
>> restored back along with its state.
>>
>> Acked-by: Thierry Reding <treding@nvidia.com>
>> Signed-off-by: Sowjanya Komatineni <skomatineni@nvidia.com>
>> ---
>>   drivers/clk/tegra/clk-pll.c      | 121 ++++++++++++++++++++++++++++-----------
>>   drivers/clk/tegra/clk-tegra210.c |   2 +-
>>   drivers/clk/tegra/clk.h          |  10 +++-
>>   3 files changed, 99 insertions(+), 34 deletions(-)
>>
>> diff --git a/drivers/clk/tegra/clk-pll.c b/drivers/clk/tegra/clk-pll.c
>> index 1583f5fc992f..f136964e6c44 100644
>> --- a/drivers/clk/tegra/clk-pll.c
>> +++ b/drivers/clk/tegra/clk-pll.c
>> @@ -1008,6 +1008,59 @@ static unsigned long clk_plle_recalc_rate(struct clk_hw *hw,
>>   	return rate;
>>   }
>>   
>> +void tegra_clk_sync_state_pll(struct clk_hw *hw)
>> +{
>> +	if (!__clk_get_enable_count(hw->clk))
>> +		clk_pll_disable(hw);
>> +	else
>> +		clk_pll_enable(hw);
>> +}
>> +
>> +static int tegra_clk_pll_save_context(struct clk_hw *hw)
>> +{
>> +	struct tegra_clk_pll *pll = to_clk_pll(hw);
>> +	u32 val = 0;
>> +
>> +	pll->rate = clk_hw_get_rate(hw);
>> +
>> +	if (pll->params->flags & TEGRA_PLLMB)
>> +		val = pll_readl_base(pll);
>> +	else if (pll->params->flags & TEGRA_PLLRE)
>> +		val = pll_readl_base(pll) & divp_mask_shifted(pll);
>> +
>> +	pll->pllbase_ctx = val;
>> +
>> +	return 0;
>> +}
>> +
>> +static void tegra_clk_pll_restore_context(struct clk_hw *hw)
>> +{
>> +	struct tegra_clk_pll *pll = to_clk_pll(hw);
>> +	struct clk_hw *parent = clk_hw_get_parent(hw);
>> +	unsigned long parent_rate = clk_hw_get_rate(parent);
>> +	u32 val;
>> +
>> +	if (clk_pll_is_enabled(hw))
>> +		return;
>> +
>> +	if (pll->params->flags & TEGRA_PLLMB) {
>> +		pll_writel_base(pll->pllbase_ctx, pll);
>> +	} else if (pll->params->flags & TEGRA_PLLRE) {
>> +		val = pll_readl_base(pll);
>> +		val &= ~(divp_mask_shifted(pll));
>> +		pll_writel_base(pll->pllbase_ctx | val, pll);
>> +	}
>> +
>> +	if (pll->params->set_defaults)
>> +		pll->params->set_defaults(pll);
>> +
>> +	clk_pll_set_rate(hw, pll->rate, parent_rate);
>> +
>> +	/* do not sync pllx state here. pllx is sync'd after dfll resume */
>> +	if (!(pll->params->flags & TEGRA_PLLX))
>> +		tegra_clk_sync_state_pll(hw);
>> +}
>> +
>>   const struct clk_ops tegra_clk_pll_ops = {
>>   	.is_enabled = clk_pll_is_enabled,
>>   	.enable = clk_pll_enable,
>> @@ -1015,6 +1068,8 @@ const struct clk_ops tegra_clk_pll_ops = {
>>   	.recalc_rate = clk_pll_recalc_rate,
>>   	.round_rate = clk_pll_round_rate,
>>   	.set_rate = clk_pll_set_rate,
>> +	.save_context = tegra_clk_pll_save_context,
>> +	.restore_context = tegra_clk_pll_restore_context,
>>   };
>>   
>>   const struct clk_ops tegra_clk_plle_ops = {
>> @@ -1802,6 +1857,27 @@ static int clk_pllu_tegra114_enable(struct clk_hw *hw)
>>   
>>   	return ret;
>>   }
>> +
>> +static void _clk_plle_tegra_init_parent(struct tegra_clk_pll *pll)
>> +{
>> +	u32 val, val_aux;
>> +
>> +	/* ensure parent is set to pll_ref */
>> +	val = pll_readl_base(pll);
>> +	val_aux = pll_readl(pll->params->aux_reg, pll);
>> +
>> +	if (val & PLL_BASE_ENABLE) {
>> +		if ((val_aux & PLLE_AUX_PLLRE_SEL) ||
>> +		    (val_aux & PLLE_AUX_PLLP_SEL))
>> +			WARN(1, "pll_e enabled with unsupported parent %s\n",
>> +			     (val_aux & PLLE_AUX_PLLP_SEL) ? "pllp_out0" :
>> +			     "pll_re_vco");
>> +	} else {
>> +		val_aux &= ~(PLLE_AUX_PLLRE_SEL | PLLE_AUX_PLLP_SEL);
>> +		pll_writel(val_aux, pll->params->aux_reg, pll);
>> +		fence_udelay(1, pll->clk_base);
>> +	}
>> +}
>>   #endif
>>   
>>   static struct tegra_clk_pll *_tegra_init_pll(void __iomem *clk_base,
>> @@ -2214,27 +2290,12 @@ struct clk *tegra_clk_register_plle_tegra114(const char *name,
>>   {
>>   	struct tegra_clk_pll *pll;
>>   	struct clk *clk;
>> -	u32 val, val_aux;
>>   
>>   	pll = _tegra_init_pll(clk_base, NULL, pll_params, lock);
>>   	if (IS_ERR(pll))
>>   		return ERR_CAST(pll);
>>   
>> -	/* ensure parent is set to pll_re_vco */
>> -
>> -	val = pll_readl_base(pll);
>> -	val_aux = pll_readl(pll_params->aux_reg, pll);
>> -
>> -	if (val & PLL_BASE_ENABLE) {
>> -		if ((val_aux & PLLE_AUX_PLLRE_SEL) ||
>> -			(val_aux & PLLE_AUX_PLLP_SEL))
>> -			WARN(1, "pll_e enabled with unsupported parent %s\n",
>> -			  (val_aux & PLLE_AUX_PLLP_SEL) ? "pllp_out0" :
>> -					"pll_re_vco");
>> -	} else {
>> -		val_aux &= ~(PLLE_AUX_PLLRE_SEL | PLLE_AUX_PLLP_SEL);
>> -		pll_writel(val_aux, pll_params->aux_reg, pll);
>> -	}
>> +	_clk_plle_tegra_init_parent(pll);
>>   
>>   	clk = _tegra_clk_register_pll(pll, name, parent_name, flags,
>>   				      &tegra_clk_plle_tegra114_ops);
>> @@ -2276,6 +2337,8 @@ static const struct clk_ops tegra_clk_pllss_ops = {
>>   	.recalc_rate = clk_pll_recalc_rate,
>>   	.round_rate = clk_pll_ramp_round_rate,
>>   	.set_rate = clk_pllxc_set_rate,
>> +	.save_context = tegra_clk_pll_save_context,
>> +	.restore_context = tegra_clk_pll_restore_context,
>>   };
>>   
>>   struct clk *tegra_clk_register_pllss(const char *name, const char *parent_name,
>> @@ -2375,6 +2438,7 @@ struct clk *tegra_clk_register_pllre_tegra210(const char *name,
>>   		pll_params->vco_min = pll_params->adjust_vco(pll_params,
>>   							     parent_rate);
>>   
>> +	pll_params->flags |= TEGRA_PLLRE;
>>   	pll = _tegra_init_pll(clk_base, pmc, pll_params, lock);
>>   	if (IS_ERR(pll))
>>   		return ERR_CAST(pll);
>> @@ -2520,11 +2584,19 @@ static void clk_plle_tegra210_disable(struct clk_hw *hw)
>>   		spin_unlock_irqrestore(pll->lock, flags);
>>   }
>>   
>> +static void tegra_clk_plle_t210_restore_context(struct clk_hw *hw)
>> +{
>> +	struct tegra_clk_pll *pll = to_clk_pll(hw);
>> +
>> +	_clk_plle_tegra_init_parent(pll);
>> +}
>> +
>>   static const struct clk_ops tegra_clk_plle_tegra210_ops = {
>>   	.is_enabled =  clk_plle_tegra210_is_enabled,
>>   	.enable = clk_plle_tegra210_enable,
>>   	.disable = clk_plle_tegra210_disable,
>>   	.recalc_rate = clk_pll_recalc_rate,
>> +	.restore_context = tegra_clk_plle_t210_restore_context,
>>   };
>>   
>>   struct clk *tegra_clk_register_plle_tegra210(const char *name,
>> @@ -2535,27 +2607,12 @@ struct clk *tegra_clk_register_plle_tegra210(const char *name,
>>   {
>>   	struct tegra_clk_pll *pll;
>>   	struct clk *clk;
>> -	u32 val, val_aux;
>>   
>>   	pll = _tegra_init_pll(clk_base, NULL, pll_params, lock);
>>   	if (IS_ERR(pll))
>>   		return ERR_CAST(pll);
>>   
>> -	/* ensure parent is set to pll_re_vco */
>> -
>> -	val = pll_readl_base(pll);
>> -	val_aux = pll_readl(pll_params->aux_reg, pll);
>> -
>> -	if (val & PLLE_BASE_ENABLE) {
>> -		if ((val_aux & PLLE_AUX_PLLRE_SEL) ||
>> -			(val_aux & PLLE_AUX_PLLP_SEL))
>> -			WARN(1, "pll_e enabled with unsupported parent %s\n",
>> -			  (val_aux & PLLE_AUX_PLLP_SEL) ? "pllp_out0" :
>> -					"pll_re_vco");
>> -	} else {
>> -		val_aux &= ~(PLLE_AUX_PLLRE_SEL | PLLE_AUX_PLLP_SEL);
>> -		pll_writel(val_aux, pll_params->aux_reg, pll);
>> -	}
>> +	_clk_plle_tegra_init_parent(pll);
>>   
>>   	clk = _tegra_clk_register_pll(pll, name, parent_name, flags,
>>   				      &tegra_clk_plle_tegra210_ops);
>> diff --git a/drivers/clk/tegra/clk-tegra210.c b/drivers/clk/tegra/clk-tegra210.c
>> index 4721ee030d1c..58397f93166c 100644
>> --- a/drivers/clk/tegra/clk-tegra210.c
>> +++ b/drivers/clk/tegra/clk-tegra210.c
>> @@ -1602,7 +1602,7 @@ static struct tegra_clk_pll_params pll_x_params = {
>>   	.pdiv_tohw = pll_qlin_pdiv_to_hw,
>>   	.div_nmp = &pllx_nmp,
>>   	.freq_table = pll_x_freq_table,
>> -	.flags = TEGRA_PLL_USE_LOCK | TEGRA_PLL_HAS_LOCK_ENABLE,
>> +	.flags = TEGRA_PLL_USE_LOCK | TEGRA_PLL_HAS_LOCK_ENABLE | TEGRA_PLLX,
>>   	.dyn_ramp = tegra210_pllx_dyn_ramp,
>>   	.set_defaults = tegra210_pllx_set_defaults,
>>   	.calc_rate = tegra210_pll_fixed_mdiv_cfg,
>> diff --git a/drivers/clk/tegra/clk.h b/drivers/clk/tegra/clk.h
>> index fb29a8c27873..8532f5150091 100644
>> --- a/drivers/clk/tegra/clk.h
>> +++ b/drivers/clk/tegra/clk.h
>> @@ -235,6 +235,8 @@ struct tegra_clk_pll;
>>    * TEGRA_PLLMB - PLLMB has should be treated similar to PLLM. This
>>    *     flag indicated that it is PLLMB.
>>    * TEGRA_PLL_VCO_OUT - Used to indicate that the PLL has a VCO output
>> + * TEGRA_PLLRE - Used to indicate that it is PLLRE.
>> + * TEGRA_PLLX - Used to indicate that it is PLLX.
>>    */
>>   struct tegra_clk_pll_params {
>>   	unsigned long	input_min;
>> @@ -301,6 +303,8 @@ struct tegra_clk_pll_params {
>>   #define TEGRA_MDIV_NEW BIT(11)
>>   #define TEGRA_PLLMB BIT(12)
>>   #define TEGRA_PLL_VCO_OUT BIT(13)
>> +#define TEGRA_PLLRE BIT(14)
>> +#define TEGRA_PLLX BIT(15)
>>   
>>   /**
>>    * struct tegra_clk_pll - Tegra PLL clock
>> @@ -310,6 +314,8 @@ struct tegra_clk_pll_params {
>>    * @pmc:	address of PMC, required to read override bits
>>    * @lock:	register lock
>>    * @params:	PLL parameters
>> + * @rate:	rate during system suspend and resume
>> + * @pllbase_ctx: pll base register value during suspend and resume
>>    */
>>   struct tegra_clk_pll {
>>   	struct clk_hw	hw;
>> @@ -317,6 +323,8 @@ struct tegra_clk_pll {
>>   	void __iomem	*pmc;
>>   	spinlock_t	*lock;
>>   	struct tegra_clk_pll_params	*params;
>> +	unsigned long	rate;
>> +	u32	pllbase_ctx;
>>   };
>>   
>>   #define to_clk_pll(_hw) container_of(_hw, struct tegra_clk_pll, hw)
>> @@ -840,7 +848,7 @@ u16 tegra_pll_get_fixed_mdiv(struct clk_hw *hw, unsigned long input_rate);
>>   int tegra_pll_p_div_to_hw(struct tegra_clk_pll *pll, u8 p_div);
>>   int div_frac_get(unsigned long rate, unsigned parent_rate, u8 width,
>>   		 u8 frac_width, u8 flags);
>> -
>> +void tegra_clk_sync_state_pll(struct clk_hw *hw);
> Looks like this function isn't used anywhere other than this patch. Bug?

With all dfll sequence moved to right places in this patch, yes this can 
be collapsed within restore context itself.

Will change in next version

>>   /* Combined read fence with delay */
>>   #define fence_udelay(delay, reg)	\
>>