1 files changed, 111 insertions, 59 deletions

diff --git a/drivers/clk/renesas/clk-div6.c b/drivers/clk/renesas/clk-div6.c
index 0627860233cb..f7b827b5e9b2 100644
--- a/drivers/clk/renesas/clk-div6.c
+++ b/drivers/clk/renesas/clk-div6.c
@@ -1,21 +1,21 @@
+// SPDX-License-Identifier: GPL-2.0
 /*
  * r8a7790 Common Clock Framework support
  *
  * Copyright (C) 2013  Renesas Solutions Corp.
  *
  * Contact: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
- *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation; version 2 of the License.
  */
 
+#include <linux/bitfield.h>
 #include <linux/clk-provider.h>
 #include <linux/init.h>
 #include <linux/io.h>
 #include <linux/kernel.h>
+#include <linux/notifier.h>
 #include <linux/of.h>
 #include <linux/of_address.h>
+#include <linux/pm.h>
 #include <linux/slab.h>
 
 #include "clk-div6.h"
@@ -29,14 +29,17 @@
  * @hw: handle between common and hardware-specific interfaces
  * @reg: IO-remapped register
  * @div: divisor value (1-64)
+ * @src_mask: Bitmask covering the register bits to select the parent clock
+ * @nb: Notifier block to save/restore clock state for system resume
+ * @parents: Array to map from valid parent clocks indices to hardware indices
  */
 struct div6_clock {
 	struct clk_hw hw;
 	void __iomem *reg;
 	unsigned int div;
-	u32 src_shift;
-	u32 src_width;
-	u8 *parents;
+	u32 src_mask;
+	struct notifier_block nb;
+	u8 parents[];
 };
 
 #define to_div6_clock(_hw) container_of(_hw, struct div6_clock, hw)
@@ -46,9 +49,9 @@ static int cpg_div6_clock_enable(struct clk_hw *hw)
 	struct div6_clock *clock = to_div6_clock(hw);
 	u32 val;
 
-	val = (clk_readl(clock->reg) & ~(CPG_DIV6_DIV_MASK | CPG_DIV6_CKSTP))
+	val = (readl(clock->reg) & ~(CPG_DIV6_DIV_MASK | CPG_DIV6_CKSTP))
 	    | CPG_DIV6_DIV(clock->div - 1);
-	clk_writel(val, clock->reg);
+	writel(val, clock->reg);
 
 	return 0;
 }
@@ -58,7 +61,7 @@ static void cpg_div6_clock_disable(struct clk_hw *hw)
 	struct div6_clock *clock = to_div6_clock(hw);
 	u32 val;
 
-	val = clk_readl(clock->reg);
+	val = readl(clock->reg);
 	val |= CPG_DIV6_CKSTP;
 	/*
 	 * DIV6 clocks require the divisor field to be non-zero when stopping
@@ -68,14 +71,14 @@ static void cpg_div6_clock_disable(struct clk_hw *hw)
 	 */
 	if (!(val & CPG_DIV6_DIV_MASK))
 		val |= CPG_DIV6_DIV_MASK;
-	clk_writel(val, clock->reg);
+	writel(val, clock->reg);
 }
 
 static int cpg_div6_clock_is_enabled(struct clk_hw *hw)
 {
 	struct div6_clock *clock = to_div6_clock(hw);
 
-	return !(clk_readl(clock->reg) & CPG_DIV6_CKSTP);
+	return !(readl(clock->reg) & CPG_DIV6_CKSTP);
 }
 
 static unsigned long cpg_div6_clock_recalc_rate(struct clk_hw *hw,
@@ -95,15 +98,52 @@ static unsigned int cpg_div6_clock_calc_div(unsigned long rate,
 		rate = 1;
 
 	div = DIV_ROUND_CLOSEST(parent_rate, rate);
-	return clamp_t(unsigned int, div, 1, 64);
+	return clamp(div, 1U, 64U);
 }
 
-static long cpg_div6_clock_round_rate(struct clk_hw *hw, unsigned long rate,
-				      unsigned long *parent_rate)
+static int cpg_div6_clock_determine_rate(struct clk_hw *hw,
+					 struct clk_rate_request *req)
 {
-	unsigned int div = cpg_div6_clock_calc_div(rate, *parent_rate);
+	unsigned long prate, calc_rate, diff, best_rate, best_prate;
+	unsigned int num_parents = clk_hw_get_num_parents(hw);
+	struct clk_hw *parent, *best_parent = NULL;
+	unsigned int i, min_div, max_div, div;
+	unsigned long min_diff = ULONG_MAX;
+
+	for (i = 0; i < num_parents; i++) {
+		parent = clk_hw_get_parent_by_index(hw, i);
+		if (!parent)
+			continue;
+
+		prate = clk_hw_get_rate(parent);
+		if (!prate)
+			continue;
+
+		min_div = max(DIV_ROUND_UP(prate, req->max_rate), 1UL);
+		max_div = req->min_rate ? min(prate / req->min_rate, 64UL) : 64;
+		if (max_div < min_div)
+			continue;
+
+		div = cpg_div6_clock_calc_div(req->rate, prate);
+		div = clamp(div, min_div, max_div);
+		calc_rate = prate / div;
+		diff = calc_rate > req->rate ? calc_rate - req->rate
+					     : req->rate - calc_rate;
+		if (diff < min_diff) {
+			best_rate = calc_rate;
+			best_parent = parent;
+			best_prate = prate;
+			min_diff = diff;
+		}
+	}
+
+	if (!best_parent)
+		return -EINVAL;
 
-	return *parent_rate / div;
+	req->best_parent_rate = best_prate;
+	req->best_parent_hw = best_parent;
+	req->rate = best_rate;
+	return 0;
 }
 
 static int cpg_div6_clock_set_rate(struct clk_hw *hw, unsigned long rate,
@@ -115,10 +155,10 @@ static int cpg_div6_clock_set_rate(struct clk_hw *hw, unsigned long rate,
 
 	clock->div = div;
 
-	val = clk_readl(clock->reg) & ~CPG_DIV6_DIV_MASK;
+	val = readl(clock->reg) & ~CPG_DIV6_DIV_MASK;
 	/* Only program the new divisor if the clock isn't stopped. */
 	if (!(val & CPG_DIV6_CKSTP))
-		clk_writel(val | CPG_DIV6_DIV(clock->div - 1), clock->reg);
+		writel(val | CPG_DIV6_DIV(clock->div - 1), clock->reg);
 
 	return 0;
 }
@@ -129,11 +169,10 @@ static u8 cpg_div6_clock_get_parent(struct clk_hw *hw)
 	unsigned int i;
 	u8 hw_index;
 
-	if (clock->src_width == 0)
+	if (clock->src_mask == 0)
 		return 0;
 
-	hw_index = (clk_readl(clock->reg) >> clock->src_shift) &
-		   (BIT(clock->src_width) - 1);
+	hw_index = field_get(clock->src_mask, readl(clock->reg));
 	for (i = 0; i < clk_hw_get_num_parents(hw); i++) {
 		if (clock->parents[i] == hw_index)
 			return i;
@@ -147,18 +186,13 @@ static u8 cpg_div6_clock_get_parent(struct clk_hw *hw)
 static int cpg_div6_clock_set_parent(struct clk_hw *hw, u8 index)
 {
 	struct div6_clock *clock = to_div6_clock(hw);
-	u8 hw_index;
-	u32 mask;
+	u32 src;
 
 	if (index >= clk_hw_get_num_parents(hw))
 		return -EINVAL;
 
-	mask = ~((BIT(clock->src_width) - 1) << clock->src_shift);
-	hw_index = clock->parents[index];
-
-	clk_writel((clk_readl(clock->reg) & mask) |
-		(hw_index << clock->src_shift), clock->reg);
-
+	src = field_prep(clock->src_mask, clock->parents[index]);
+	writel((readl(clock->reg) & ~clock->src_mask) | src, clock->reg);
 	return 0;
 }
 
@@ -169,10 +203,33 @@ static const struct clk_ops cpg_div6_clock_ops = {
 	.get_parent = cpg_div6_clock_get_parent,
 	.set_parent = cpg_div6_clock_set_parent,
 	.recalc_rate = cpg_div6_clock_recalc_rate,
-	.round_rate = cpg_div6_clock_round_rate,
+	.determine_rate = cpg_div6_clock_determine_rate,
 	.set_rate = cpg_div6_clock_set_rate,
 };
 
+static int cpg_div6_clock_notifier_call(struct notifier_block *nb,
+					unsigned long action, void *data)
+{
+	struct div6_clock *clock = container_of(nb, struct div6_clock, nb);
+
+	switch (action) {
+	case PM_EVENT_RESUME:
+		/*
+		 * TODO: This does not yet support DIV6 clocks with multiple
+		 * parents, as the parent selection bits are not restored.
+		 * Fortunately so far such DIV6 clocks are found only on
+		 * R/SH-Mobile SoCs, while the resume functionality is only
+		 * needed on R-Car Gen3.
+		 */
+		if (__clk_get_enable_count(clock->hw.clk))
+			cpg_div6_clock_enable(&clock->hw);
+		else
+			cpg_div6_clock_disable(&clock->hw);
+		return NOTIFY_OK;
+	}
+
+	return NOTIFY_DONE;
+}
 
 /**
  * cpg_div6_register - Register a DIV6 clock
@@ -180,57 +237,50 @@ static const struct clk_ops cpg_div6_clock_ops = {
  * @num_parents: Number of parent clocks of the DIV6 clock (1, 4, or 8)
  * @parent_names: Array containing the names of the parent clocks
  * @reg: Mapped register used to control the DIV6 clock
+ * @notifiers: Optional notifier chain to save/restore state for system resume
  */
 struct clk * __init cpg_div6_register(const char *name,
 				      unsigned int num_parents,
 				      const char **parent_names,
-				      void __iomem *reg)
+				      void __iomem *reg,
+				      struct raw_notifier_head *notifiers)
 {
 	unsigned int valid_parents;
-	struct clk_init_data init;
+	struct clk_init_data init = {};
 	struct div6_clock *clock;
 	struct clk *clk;
 	unsigned int i;
 
-	clock = kzalloc(sizeof(*clock), GFP_KERNEL);
+	clock = kzalloc(struct_size(clock, parents, num_parents), GFP_KERNEL);
 	if (!clock)
 		return ERR_PTR(-ENOMEM);
 
-	clock->parents = kmalloc_array(num_parents, sizeof(*clock->parents),
-				       GFP_KERNEL);
-	if (!clock->parents) {
-		clk = ERR_PTR(-ENOMEM);
-		goto free_clock;
-	}
-
 	clock->reg = reg;
 
 	/*
 	 * Read the divisor. Disabling the clock overwrites the divisor, so we
 	 * need to cache its value for the enable operation.
 	 */
-	clock->div = (clk_readl(clock->reg) & CPG_DIV6_DIV_MASK) + 1;
+	clock->div = (readl(clock->reg) & CPG_DIV6_DIV_MASK) + 1;
 
 	switch (num_parents) {
 	case 1:
 		/* fixed parent clock */
-		clock->src_shift = clock->src_width = 0;
+		clock->src_mask = 0;
 		break;
 	case 4:
 		/* clock with EXSRC bits 6-7 */
-		clock->src_shift = 6;
-		clock->src_width = 2;
+		clock->src_mask = GENMASK(7, 6);
 		break;
 	case 8:
 		/* VCLK with EXSRC bits 12-14 */
-		clock->src_shift = 12;
-		clock->src_width = 3;
+		clock->src_mask = GENMASK(14, 12);
 		break;
 	default:
 		pr_err("%s: invalid number of parents for DIV6 clock %s\n",
 		       __func__, name);
 		clk = ERR_PTR(-EINVAL);
-		goto free_parents;
+		goto free_clock;
 	}
 
 	/* Filter out invalid parents */
@@ -245,7 +295,6 @@ struct clk * __init cpg_div6_register(const char *name,
 	/* Register the clock. */
 	init.name = name;
 	init.ops = &cpg_div6_clock_ops;
-	init.flags = CLK_IS_BASIC;
 	init.parent_names = parent_names;
 	init.num_parents = valid_parents;
 
@@ -253,12 +302,15 @@ struct clk * __init cpg_div6_register(const char *name,
 
 	clk = clk_register(NULL, &clock->hw);
 	if (IS_ERR(clk))
-		goto free_parents;
+		goto free_clock;
+
+	if (notifiers) {
+		clock->nb.notifier_call = cpg_div6_clock_notifier_call;
+		raw_notifier_chain_register(notifiers, &clock->nb);
+	}
 
 	return clk;
 
-free_parents:
-	kfree(clock->parents);
 free_clock:
 	kfree(clock);
 	return clk;
@@ -275,8 +327,8 @@ static void __init cpg_div6_clock_init(struct device_node *np)
 
 	num_parents = of_clk_get_parent_count(np);
 	if (num_parents < 1) {
-		pr_err("%s: no parent found for %s DIV6 clock\n",
-		       __func__, np->name);
+		pr_err("%s: no parent found for %pOFn DIV6 clock\n",
+		       __func__, np);
 		return;
 	}
 
@@ -287,8 +339,8 @@ static void __init cpg_div6_clock_init(struct device_node *np)
 
 	reg = of_iomap(np, 0);
 	if (reg == NULL) {
-		pr_err("%s: failed to map %s DIV6 clock register\n",
-		       __func__, np->name);
+		pr_err("%s: failed to map %pOFn DIV6 clock register\n",
+		       __func__, np);
 		goto error;
 	}
 
@@ -298,10 +350,10 @@ static void __init cpg_div6_clock_init(struct device_node *np)
 	for (i = 0; i < num_parents; i++)
 		parent_names[i] = of_clk_get_parent_name(np, i);
 
-	clk = cpg_div6_register(clk_name, num_parents, parent_names, reg);
+	clk = cpg_div6_register(clk_name, num_parents, parent_names, reg, NULL);
 	if (IS_ERR(clk)) {
-		pr_err("%s: failed to register %s DIV6 clock (%ld)\n",
-		       __func__, np->name, PTR_ERR(clk));
+		pr_err("%s: failed to register %pOFn DIV6 clock (%ld)\n",
+		       __func__, np, PTR_ERR(clk));
 		goto error;
 	}