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Subject[PATCH] clk: Add functions to save and restore clock/dpll context en-masse
Date
From: Russ Dill <Russ.Dill@ti.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@ti.com>
Signed-off-by: Keerthy <j-keerthy@ti.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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