Re: [PATCH] clk: Add functions to save and restore clock/dpll context en-masse
From: Peter De Schrijver
Date: Thu May 04 2017 - 03:51:50 EST
On Tue, Apr 18, 2017 at 10:42:49AM +0530, Keerthy wrote:
> From: Russ Dill <Russ.Dill@xxxxxx>
>
> The clock/dpll registers are in the WKUP power domain. Under both RTC-only
> suspend and hibernation, these registers are lost. Hence save/restore
> them accordingly.
>
This won't work for Tegra, because we need a 2 pass restore. First restore
rate/parents with all clocks enabled and then disable the ones which were
disabled before entering suspend. Both passes usually go from root to leave.
However a few clocks have to be treated separately, eg the ones related to
SDRAM.
Peter.
> Signed-off-by: Russ Dill <Russ.Dill@xxxxxx>
> Signed-off-by: Keerthy <j-keerthy@xxxxxx>
> ---
> drivers/clk/clk.c | 70 ++++++++++++++++++++++++
> drivers/clk/ti/divider.c | 36 +++++++++++++
> drivers/clk/ti/dpll.c | 6 +++
> drivers/clk/ti/dpll3xxx.c | 124 +++++++++++++++++++++++++++++++++++++++++++
> drivers/clk/ti/gate.c | 3 ++
> drivers/clk/ti/mux.c | 29 ++++++++++
> include/linux/clk-provider.h | 11 ++++
> include/linux/clk.h | 25 +++++++++
> include/linux/clk/ti.h | 6 +++
> 9 files changed, 310 insertions(+)
>
> diff --git a/drivers/clk/clk.c b/drivers/clk/clk.c
> index cddddbe..1ca87f4 100644
> --- a/drivers/clk/clk.c
> +++ b/drivers/clk/clk.c
> @@ -687,6 +687,76 @@ static int clk_core_enable_lock(struct clk_core *core)
> return ret;
> }
>
> +void clk_dflt_restore_context(struct clk_hw *hw)
> +{
> + if (hw->clk->core->enable_count)
> + hw->clk->core->ops->enable(hw);
> + else
> + hw->clk->core->ops->disable(hw);
> +}
> +EXPORT_SYMBOL_GPL(clk_dflt_restore_context);
> +
> +static int clk_save_context(struct clk_core *clk)
> +{
> + struct clk_core *child;
> + int ret = 0;
> +
> + hlist_for_each_entry(child, &clk->children, child_node) {
> + ret = clk_save_context(child);
> + if (ret < 0)
> + return ret;
> + }
> +
> + if (clk->ops && clk->ops->save_context)
> + ret = clk->ops->save_context(clk->hw);
> +
> + return ret;
> +}
> +
> +static void clk_restore_context(struct clk_core *clk)
> +{
> + struct clk_core *child;
> +
> + if (clk->ops && clk->ops->restore_context)
> + clk->ops->restore_context(clk->hw);
> +
> + hlist_for_each_entry(child, &clk->children, child_node)
> + clk_restore_context(child);
> +}
> +
> +int clks_save_context(void)
> +{
> + struct clk_core *clk;
> + int ret;
> +
> + hlist_for_each_entry(clk, &clk_root_list, child_node) {
> + ret = clk_save_context(clk);
> + if (ret < 0)
> + return ret;
> + }
> +
> + hlist_for_each_entry(clk, &clk_orphan_list, child_node) {
> + ret = clk_save_context(clk);
> + if (ret < 0)
> + return ret;
> + }
> +
> + return 0;
> +}
> +EXPORT_SYMBOL_GPL(clks_save_context);
> +
> +void clks_restore_context(void)
> +{
> + struct clk_core *clk;
> +
> + hlist_for_each_entry(clk, &clk_root_list, child_node)
> + clk_restore_context(clk);
> +
> + hlist_for_each_entry(clk, &clk_orphan_list, child_node)
> + clk_restore_context(clk);
> +}
> +EXPORT_SYMBOL_GPL(clks_restore_context);
> +
> /**
> * clk_enable - ungate a clock
> * @clk: the clk being ungated
> diff --git a/drivers/clk/ti/divider.c b/drivers/clk/ti/divider.c
> index d6dcb28..350a58a 100644
> --- a/drivers/clk/ti/divider.c
> +++ b/drivers/clk/ti/divider.c
> @@ -266,10 +266,46 @@ static int ti_clk_divider_set_rate(struct clk_hw *hw, unsigned long rate,
> return 0;
> }
>
> +/**
> + * clk_divider_save_context - Save the divider value
> + * @hw: pointer struct clk_hw
> + *
> + * Save the divider value
> + */
> +static int clk_divider_save_context(struct clk_hw *hw)
> +{
> + struct clk_divider *divider = to_clk_divider(hw);
> + u32 val;
> +
> + val = ti_clk_ll_ops->clk_readl(divider->reg) >> divider->shift;
> + divider->context = val & div_mask(divider);
> +
> + return 0;
> +}
> +
> +/**
> + * clk_divider_restore_context - restore the saved the divider value
> + * @hw: pointer struct clk_hw
> + *
> + * Restore the saved the divider value
> + */
> +static void clk_divider_restore_context(struct clk_hw *hw)
> +{
> + struct clk_divider *divider = to_clk_divider(hw);
> + u32 val;
> +
> + val = ti_clk_ll_ops->clk_readl(divider->reg);
> + val &= ~(div_mask(divider) << divider->shift);
> + val |= divider->context << divider->shift;
> + ti_clk_ll_ops->clk_writel(val, divider->reg);
> +}
> +
> const struct clk_ops ti_clk_divider_ops = {
> .recalc_rate = ti_clk_divider_recalc_rate,
> .round_rate = ti_clk_divider_round_rate,
> .set_rate = ti_clk_divider_set_rate,
> + .save_context = clk_divider_save_context,
> + .restore_context = clk_divider_restore_context,
> };
>
> static struct clk *_register_divider(struct device *dev, const char *name,
> diff --git a/drivers/clk/ti/dpll.c b/drivers/clk/ti/dpll.c
> index 96d8488..791dd31 100644
> --- a/drivers/clk/ti/dpll.c
> +++ b/drivers/clk/ti/dpll.c
> @@ -39,6 +39,8 @@
> .set_rate_and_parent = &omap3_noncore_dpll_set_rate_and_parent,
> .determine_rate = &omap4_dpll_regm4xen_determine_rate,
> .get_parent = &omap2_init_dpll_parent,
> + .save_context = &omap3_core_dpll_save_context,
> + .restore_context = &omap3_core_dpll_restore_context,
> };
> #else
> static const struct clk_ops dpll_m4xen_ck_ops = {};
> @@ -62,6 +64,8 @@
> .set_rate_and_parent = &omap3_noncore_dpll_set_rate_and_parent,
> .determine_rate = &omap3_noncore_dpll_determine_rate,
> .get_parent = &omap2_init_dpll_parent,
> + .save_context = &omap3_noncore_dpll_save_context,
> + .restore_context = &omap3_noncore_dpll_restore_context,
> };
>
> static const struct clk_ops dpll_no_gate_ck_ops = {
> @@ -72,6 +76,8 @@
> .set_parent = &omap3_noncore_dpll_set_parent,
> .set_rate_and_parent = &omap3_noncore_dpll_set_rate_and_parent,
> .determine_rate = &omap3_noncore_dpll_determine_rate,
> + .save_context = &omap3_noncore_dpll_save_context,
> + .restore_context = &omap3_noncore_dpll_restore_context
> };
> #else
> static const struct clk_ops dpll_core_ck_ops = {};
> diff --git a/drivers/clk/ti/dpll3xxx.c b/drivers/clk/ti/dpll3xxx.c
> index 4534de2..44b6b64 100644
> --- a/drivers/clk/ti/dpll3xxx.c
> +++ b/drivers/clk/ti/dpll3xxx.c
> @@ -782,6 +782,130 @@ unsigned long omap3_clkoutx2_recalc(struct clk_hw *hw,
> return rate;
> }
>
> +/**
> + * omap3_core_dpll_save_context - Save the m and n values of the divider
> + * @hw: pointer struct clk_hw
> + *
> + * Before the dpll registers are lost save the last rounded rate m and n
> + * and the enable mask.
> + */
> +int omap3_core_dpll_save_context(struct clk_hw *hw)
> +{
> + struct clk_hw_omap *clk = to_clk_hw_omap(hw);
> + struct dpll_data *dd;
> + u32 v;
> +
> + dd = clk->dpll_data;
> +
> + v = ti_clk_ll_ops->clk_readl(&dd->control_reg);
> + clk->context = (v & dd->enable_mask) >> __ffs(dd->enable_mask);
> +
> + if (clk->context == DPLL_LOCKED) {
> + v = ti_clk_ll_ops->clk_readl(&dd->mult_div1_reg);
> + dd->last_rounded_m = (v & dd->mult_mask) >>
> + __ffs(dd->mult_mask);
> + dd->last_rounded_n = ((v & dd->div1_mask) >>
> + __ffs(dd->div1_mask)) + 1;
> + }
> +
> + return 0;
> +}
> +
> +/**
> + * omap3_core_dpll_restore_context - restore the m and n values of the divider
> + * @hw: pointer struct clk_hw
> + *
> + * Restore the last rounded rate m and n
> + * and the enable mask.
> + */
> +void omap3_core_dpll_restore_context(struct clk_hw *hw)
> +{
> + struct clk_hw_omap *clk = to_clk_hw_omap(hw);
> + const struct dpll_data *dd;
> + u32 v;
> +
> + dd = clk->dpll_data;
> +
> + if (clk->context == DPLL_LOCKED) {
> + _omap3_dpll_write_clken(clk, 0x4);
> + _omap3_wait_dpll_status(clk, 0);
> +
> + v = ti_clk_ll_ops->clk_readl(&dd->mult_div1_reg);
> + v &= ~(dd->mult_mask | dd->div1_mask);
> + v |= dd->last_rounded_m << __ffs(dd->mult_mask);
> + v |= (dd->last_rounded_n - 1) << __ffs(dd->div1_mask);
> + ti_clk_ll_ops->clk_writel(v, &dd->mult_div1_reg);
> +
> + _omap3_dpll_write_clken(clk, DPLL_LOCKED);
> + _omap3_wait_dpll_status(clk, 1);
> + } else {
> + _omap3_dpll_write_clken(clk, clk->context);
> + }
> +}
> +
> +/**
> + * omap3_non_core_dpll_save_context - Save the m and n values of the divider
> + * @hw: pointer struct clk_hw
> + *
> + * Before the dpll registers are lost save the last rounded rate m and n
> + * and the enable mask.
> + */
> +int omap3_noncore_dpll_save_context(struct clk_hw *hw)
> +{
> + struct clk_hw_omap *clk = to_clk_hw_omap(hw);
> + struct dpll_data *dd;
> + u32 v;
> +
> + dd = clk->dpll_data;
> +
> + v = ti_clk_ll_ops->clk_readl(&dd->control_reg);
> + clk->context = (v & dd->enable_mask) >> __ffs(dd->enable_mask);
> +
> + if (clk->context == DPLL_LOCKED) {
> + v = ti_clk_ll_ops->clk_readl(&dd->mult_div1_reg);
> + dd->last_rounded_m = (v & dd->mult_mask) >>
> + __ffs(dd->mult_mask);
> + dd->last_rounded_n = ((v & dd->div1_mask) >>
> + __ffs(dd->div1_mask)) + 1;
> + }
> +
> + return 0;
> +}
> +
> +/**
> + * omap3_core_dpll_restore_context - restore the m and n values of the divider
> + * @hw: pointer struct clk_hw
> + *
> + * Restore the last rounded rate m and n
> + * and the enable mask.
> + */
> +void omap3_noncore_dpll_restore_context(struct clk_hw *hw)
> +{
> + struct clk_hw_omap *clk = to_clk_hw_omap(hw);
> + const struct dpll_data *dd;
> + u32 ctrl, mult_div1;
> +
> + dd = clk->dpll_data;
> +
> + ctrl = ti_clk_ll_ops->clk_readl(&dd->control_reg);
> + mult_div1 = ti_clk_ll_ops->clk_readl(&dd->mult_div1_reg);
> +
> + if (clk->context == ((ctrl & dd->enable_mask) >>
> + __ffs(dd->enable_mask)) &&
> + dd->last_rounded_m == ((mult_div1 & dd->mult_mask) >>
> + __ffs(dd->mult_mask)) &&
> + dd->last_rounded_n == ((mult_div1 & dd->div1_mask) >>
> + __ffs(dd->div1_mask)) + 1) {
> + /* nothing to be done */
> + return;
> + }
> +
> + if (clk->context == DPLL_LOCKED)
> + omap3_noncore_dpll_program(clk, 0);
> + else
> + _omap3_dpll_write_clken(clk, clk->context);
> +}
> +
> /* OMAP3/4 non-CORE DPLL clkops */
> const struct clk_hw_omap_ops clkhwops_omap3_dpll = {
> .allow_idle = omap3_dpll_allow_idle,
> diff --git a/drivers/clk/ti/gate.c b/drivers/clk/ti/gate.c
> index 7151ec3..098db66 100644
> --- a/drivers/clk/ti/gate.c
> +++ b/drivers/clk/ti/gate.c
> @@ -33,6 +33,7 @@
> .init = &omap2_init_clk_clkdm,
> .enable = &omap2_clkops_enable_clkdm,
> .disable = &omap2_clkops_disable_clkdm,
> + .restore_context = clk_dflt_restore_context,
> };
>
> const struct clk_ops omap_gate_clk_ops = {
> @@ -40,6 +41,7 @@
> .enable = &omap2_dflt_clk_enable,
> .disable = &omap2_dflt_clk_disable,
> .is_enabled = &omap2_dflt_clk_is_enabled,
> + .restore_context = clk_dflt_restore_context,
> };
>
> static const struct clk_ops omap_gate_clk_hsdiv_restore_ops = {
> @@ -47,6 +49,7 @@
> .enable = &omap36xx_gate_clk_enable_with_hsdiv_restore,
> .disable = &omap2_dflt_clk_disable,
> .is_enabled = &omap2_dflt_clk_is_enabled,
> + .restore_context = clk_dflt_restore_context,
> };
>
> /**
> diff --git a/drivers/clk/ti/mux.c b/drivers/clk/ti/mux.c
> index 18c267b..e73764a 100644
> --- a/drivers/clk/ti/mux.c
> +++ b/drivers/clk/ti/mux.c
> @@ -90,10 +90,39 @@ static int ti_clk_mux_set_parent(struct clk_hw *hw, u8 index)
> return 0;
> }
>
> +/**
> + * clk_mux_save_context - Save the parent selcted in the mux
> + * @hw: pointer struct clk_hw
> + *
> + * Save the parent mux value.
> + */
> +static int clk_mux_save_context(struct clk_hw *hw)
> +{
> + struct clk_mux *mux = to_clk_mux(hw);
> +
> + mux->saved_parent = ti_clk_mux_get_parent(hw);
> + return 0;
> +}
> +
> +/**
> + * clk_mux_restore_context - Restore the parent in the mux
> + * @hw: pointer struct clk_hw
> + *
> + * Restore the saved parent mux value.
> + */
> +static void clk_mux_restore_context(struct clk_hw *hw)
> +{
> + struct clk_mux *mux = to_clk_mux(hw);
> +
> + ti_clk_mux_set_parent(hw, mux->saved_parent);
> +}
> +
> const struct clk_ops ti_clk_mux_ops = {
> .get_parent = ti_clk_mux_get_parent,
> .set_parent = ti_clk_mux_set_parent,
> .determine_rate = __clk_mux_determine_rate,
> + .save_context = clk_mux_save_context,
> + .restore_context = clk_mux_restore_context,
> };
>
> static struct clk *_register_mux(struct device *dev, const char *name,
> diff --git a/include/linux/clk-provider.h b/include/linux/clk-provider.h
> index a428aec..2a8f636 100644
> --- a/include/linux/clk-provider.h
> +++ b/include/linux/clk-provider.h
> @@ -103,6 +103,11 @@ struct clk_rate_request {
> * Called with enable_lock held. This function must not
> * sleep.
> *
> + * @save_context: Save the context of the clock in prepration for poweroff.
> + *
> + * @restore_context: Restore the context of the clock after a restoration
> + * of power.
> + *
> * @recalc_rate Recalculate the rate of this clock, by querying hardware. The
> * parent rate is an input parameter. It is up to the caller to
> * ensure that the prepare_mutex is held across this call.
> @@ -198,6 +203,8 @@ struct clk_ops {
> void (*disable)(struct clk_hw *hw);
> int (*is_enabled)(struct clk_hw *hw);
> void (*disable_unused)(struct clk_hw *hw);
> + int (*save_context)(struct clk_hw *hw);
> + void (*restore_context)(struct clk_hw *hw);
> unsigned long (*recalc_rate)(struct clk_hw *hw,
> unsigned long parent_rate);
> long (*round_rate)(struct clk_hw *hw, unsigned long rate,
> @@ -394,6 +401,7 @@ struct clk_divider {
> u8 flags;
> const struct clk_div_table *table;
> spinlock_t *lock;
> + u32 context;
> };
>
> #define to_clk_divider(_hw) container_of(_hw, struct clk_divider, hw)
> @@ -471,6 +479,7 @@ struct clk_mux {
> u8 shift;
> u8 flags;
> spinlock_t *lock;
> + u8 saved_parent;
> };
>
> #define to_clk_mux(_hw) container_of(_hw, struct clk_mux, hw)
> @@ -912,5 +921,7 @@ struct dentry *clk_debugfs_add_file(struct clk_hw *hw, char *name, umode_t mode,
> void *data, const struct file_operations *fops);
> #endif
>
> +void clk_dflt_restore_context(struct clk_hw *hw);
> +
> #endif /* CONFIG_COMMON_CLK */
> #endif /* CLK_PROVIDER_H */
> diff --git a/include/linux/clk.h b/include/linux/clk.h
> index 024cd07..d071a65 100644
> --- a/include/linux/clk.h
> +++ b/include/linux/clk.h
> @@ -438,6 +438,23 @@ struct clk *devm_get_clk_from_child(struct device *dev,
> */
> struct clk *clk_get_sys(const char *dev_id, const char *con_id);
>
> +/**
> + * clks_save_context - save clock context for poweroff
> + *
> + * Saves the context of the clock register for powerstates in which the
> + * contents of the registers will be lost. Occurs deep within the suspend
> + * code so locking is not necessary.
> + */
> +int clks_save_context(void);
> +
> +/**
> + * clks_restore_context - restore clock context after poweroff
> + *
> + * This occurs with all clocks enabled. Occurs deep within the resume code
> + * so locking is not necessary.
> + */
> +void clks_restore_context(void);
> +
> #else /* !CONFIG_HAVE_CLK */
>
> static inline struct clk *clk_get(struct device *dev, const char *id)
> @@ -501,6 +518,14 @@ static inline struct clk *clk_get_sys(const char *dev_id, const char *con_id)
> {
> return NULL;
> }
> +
> +static inline int clks_save_context(void)
> +{
> + return 0;
> +}
> +
> +static inline void clks_restore_context(void) {}
> +
> #endif
>
> /* clk_prepare_enable helps cases using clk_enable in non-atomic context. */
> diff --git a/include/linux/clk/ti.h b/include/linux/clk/ti.h
> index d18da83..f604936 100644
> --- a/include/linux/clk/ti.h
> +++ b/include/linux/clk/ti.h
> @@ -159,6 +159,7 @@ struct clk_hw_omap {
> const char *clkdm_name;
> struct clockdomain *clkdm;
> const struct clk_hw_omap_ops *ops;
> + u32 context;
> };
>
> /*
> @@ -290,6 +291,11 @@ struct ti_clk_features {
>
> void ti_clk_setup_features(struct ti_clk_features *features);
> const struct ti_clk_features *ti_clk_get_features(void);
> +int omap3_noncore_dpll_save_context(struct clk_hw *hw);
> +void omap3_noncore_dpll_restore_context(struct clk_hw *hw);
> +
> +int omap3_core_dpll_save_context(struct clk_hw *hw);
> +void omap3_core_dpll_restore_context(struct clk_hw *hw);
>
> extern const struct clk_hw_omap_ops clkhwops_omap2xxx_dpll;
>
> --
> 1.9.1
>
> --
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