Message-ID: <1492492369-19662-1-git-send-email-j-keerthy@ti.com>
Date:   Tue, 18 Apr 2017 10:42:49 +0530
From:   Keerthy <j-keerthy@...com>
To:     <sboyd@...eaurora.org>, <t-kristo@...com>,
        <mturquette@...libre.com>
CC:     <j-keerthy@...com>, <linux@...linux.org.uk>,
        <linux-clk@...r.kernel.org>, <linux-kernel@...r.kernel.org>,
        <linux-omap@...r.kernel.org>, Russ Dill <Russ.Dill@...com>
Subject: [PATCH] clk: Add functions to save and restore clock/dpll context en-masse

From: Russ Dill <Russ.Dill@...com>

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.

Signed-off-by: Russ Dill <Russ.Dill@...com>
Signed-off-by: Keerthy <j-keerthy@...com>
---
 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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