1 files changed, 342 insertions, 0 deletions
diff --git a/drivers/clk/renesas/clk-mstp.c b/drivers/clk/renesas/clk-mstp.c
new file mode 100644
index 000000000..90804ac06
--- /dev/null
+++ b/drivers/clk/renesas/clk-mstp.c
@@ -0,0 +1,342 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * R-Car MSTP clocks
+ *
+ * Copyright (C) 2013 Ideas On Board SPRL
+ * Copyright (C) 2015 Glider bvba
+ *
+ * Contact: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
+ */
+
+#include <linux/clk.h>
+#include <linux/clk-provider.h>
+#include <linux/clkdev.h>
+#include <linux/clk/renesas.h>
+#include <linux/device.h>
+#include <linux/io.h>
+#include <linux/of.h>
+#include <linux/of_address.h>
+#include <linux/pm_clock.h>
+#include <linux/pm_domain.h>
+#include <linux/spinlock.h>
+
+/*
+ * MSTP clocks. We can't use standard gate clocks as we need to poll on the
+ * status register when enabling the clock.
+ */
+
+#define MSTP_MAX_CLOCKS		32
+
+/**
+ * struct mstp_clock_group - MSTP gating clocks group
+ *
+ * @data: clock specifier translation for clocks in this group
+ * @smstpcr: module stop control register
+ * @mstpsr: module stop status register (optional)
+ * @lock: protects writes to SMSTPCR
+ * @width_8bit: registers are 8-bit, not 32-bit
+ * @clks: clocks in this group
+ */
+struct mstp_clock_group {
+	struct clk_onecell_data data;
+	void __iomem *smstpcr;
+	void __iomem *mstpsr;
+	spinlock_t lock;
+	bool width_8bit;
+	struct clk *clks[];
+};
+
+/**
+ * struct mstp_clock - MSTP gating clock
+ * @hw: handle between common and hardware-specific interfaces
+ * @bit_index: control bit index
+ * @group: MSTP clocks group
+ */
+struct mstp_clock {
+	struct clk_hw hw;
+	u32 bit_index;
+	struct mstp_clock_group *group;
+};
+
+#define to_mstp_clock(_hw) container_of(_hw, struct mstp_clock, hw)
+
+static inline u32 cpg_mstp_read(struct mstp_clock_group *group,
+				u32 __iomem *reg)
+{
+	return group->width_8bit ? readb(reg) : readl(reg);
+}
+
+static inline void cpg_mstp_write(struct mstp_clock_group *group, u32 val,
+				  u32 __iomem *reg)
+{
+	group->width_8bit ? writeb(val, reg) : writel(val, reg);
+}
+
+static int cpg_mstp_clock_endisable(struct clk_hw *hw, bool enable)
+{
+	struct mstp_clock *clock = to_mstp_clock(hw);
+	struct mstp_clock_group *group = clock->group;
+	u32 bitmask = BIT(clock->bit_index);
+	unsigned long flags;
+	unsigned int i;
+	u32 value;
+
+	spin_lock_irqsave(&group->lock, flags);
+
+	value = cpg_mstp_read(group, group->smstpcr);
+	if (enable)
+		value &= ~bitmask;
+	else
+		value |= bitmask;
+	cpg_mstp_write(group, value, group->smstpcr);
+
+	if (!group->mstpsr) {
+		/* dummy read to ensure write has completed */
+		cpg_mstp_read(group, group->smstpcr);
+		barrier_data(group->smstpcr);
+	}
+
+	spin_unlock_irqrestore(&group->lock, flags);
+
+	if (!enable || !group->mstpsr)
+		return 0;
+
+	for (i = 1000; i > 0; --i) {
+		if (!(cpg_mstp_read(group, group->mstpsr) & bitmask))
+			break;
+		cpu_relax();
+	}
+
+	if (!i) {
+		pr_err("%s: failed to enable %p[%d]\n", __func__,
+		       group->smstpcr, clock->bit_index);
+		return -ETIMEDOUT;
+	}
+
+	return 0;
+}
+
+static int cpg_mstp_clock_enable(struct clk_hw *hw)
+{
+	return cpg_mstp_clock_endisable(hw, true);
+}
+
+static void cpg_mstp_clock_disable(struct clk_hw *hw)
+{
+	cpg_mstp_clock_endisable(hw, false);
+}
+
+static int cpg_mstp_clock_is_enabled(struct clk_hw *hw)
+{
+	struct mstp_clock *clock = to_mstp_clock(hw);
+	struct mstp_clock_group *group = clock->group;
+	u32 value;
+
+	if (group->mstpsr)
+		value = cpg_mstp_read(group, group->mstpsr);
+	else
+		value = cpg_mstp_read(group, group->smstpcr);
+
+	return !(value & BIT(clock->bit_index));
+}
+
+static const struct clk_ops cpg_mstp_clock_ops = {
+	.enable = cpg_mstp_clock_enable,
+	.disable = cpg_mstp_clock_disable,
+	.is_enabled = cpg_mstp_clock_is_enabled,
+};
+
+static struct clk * __init cpg_mstp_clock_register(const char *name,
+	const char *parent_name, unsigned int index,
+	struct mstp_clock_group *group)
+{
+	struct clk_init_data init = {};
+	struct mstp_clock *clock;
+	struct clk *clk;
+
+	clock = kzalloc(sizeof(*clock), GFP_KERNEL);
+	if (!clock)
+		return ERR_PTR(-ENOMEM);
+
+	init.name = name;
+	init.ops = &cpg_mstp_clock_ops;
+	init.flags = CLK_SET_RATE_PARENT;
+	/* INTC-SYS is the module clock of the GIC, and must not be disabled */
+	if (!strcmp(name, "intc-sys")) {
+		pr_debug("MSTP %s setting CLK_IS_CRITICAL\n", name);
+		init.flags |= CLK_IS_CRITICAL;
+	}
+	init.parent_names = &parent_name;
+	init.num_parents = 1;
+
+	clock->bit_index = index;
+	clock->group = group;
+	clock->hw.init = &init;
+
+	clk = clk_register(NULL, &clock->hw);
+
+	if (IS_ERR(clk))
+		kfree(clock);
+
+	return clk;
+}
+
+static void __init cpg_mstp_clocks_init(struct device_node *np)
+{
+	struct mstp_clock_group *group;
+	const char *idxname;
+	struct clk **clks;
+	unsigned int i;
+
+	group = kzalloc(struct_size(group, clks, MSTP_MAX_CLOCKS), GFP_KERNEL);
+	if (!group)
+		return;
+
+	clks = group->clks;
+	spin_lock_init(&group->lock);
+	group->data.clks = clks;
+
+	group->smstpcr = of_iomap(np, 0);
+	group->mstpsr = of_iomap(np, 1);
+
+	if (group->smstpcr == NULL) {
+		pr_err("%s: failed to remap SMSTPCR\n", __func__);
+		kfree(group);
+		return;
+	}
+
+	if (of_device_is_compatible(np, "renesas,r7s72100-mstp-clocks"))
+		group->width_8bit = true;
+
+	for (i = 0; i < MSTP_MAX_CLOCKS; ++i)
+		clks[i] = ERR_PTR(-ENOENT);
+
+	if (of_find_property(np, "clock-indices", &i))
+		idxname = "clock-indices";
+	else
+		idxname = "renesas,clock-indices";
+
+	for (i = 0; i < MSTP_MAX_CLOCKS; ++i) {
+		const char *parent_name;
+		const char *name;
+		u32 clkidx;
+		int ret;
+
+		/* Skip clocks with no name. */
+		ret = of_property_read_string_index(np, "clock-output-names",
+						    i, &name);
+		if (ret < 0 || strlen(name) == 0)
+			continue;
+
+		parent_name = of_clk_get_parent_name(np, i);
+		ret = of_property_read_u32_index(np, idxname, i, &clkidx);
+		if (parent_name == NULL || ret < 0)
+			break;
+
+		if (clkidx >= MSTP_MAX_CLOCKS) {
+			pr_err("%s: invalid clock %pOFn %s index %u\n",
+			       __func__, np, name, clkidx);
+			continue;
+		}
+
+		clks[clkidx] = cpg_mstp_clock_register(name, parent_name,
+						       clkidx, group);
+		if (!IS_ERR(clks[clkidx])) {
+			group->data.clk_num = max(group->data.clk_num,
+						  clkidx + 1);
+			/*
+			 * Register a clkdev to let board code retrieve the
+			 * clock by name and register aliases for non-DT
+			 * devices.
+			 *
+			 * FIXME: Remove this when all devices that require a
+			 * clock will be instantiated from DT.
+			 */
+			clk_register_clkdev(clks[clkidx], name, NULL);
+		} else {
+			pr_err("%s: failed to register %pOFn %s clock (%ld)\n",
+			       __func__, np, name, PTR_ERR(clks[clkidx]));
+		}
+	}
+
+	of_clk_add_provider(np, of_clk_src_onecell_get, &group->data);
+}
+CLK_OF_DECLARE(cpg_mstp_clks, "renesas,cpg-mstp-clocks", cpg_mstp_clocks_init);
+
+int cpg_mstp_attach_dev(struct generic_pm_domain *unused, struct device *dev)
+{
+	struct device_node *np = dev->of_node;
+	struct of_phandle_args clkspec;
+	struct clk *clk;
+	int i = 0;
+	int error;
+
+	while (!of_parse_phandle_with_args(np, "clocks", "#clock-cells", i,
+					   &clkspec)) {
+		if (of_device_is_compatible(clkspec.np,
+					    "renesas,cpg-mstp-clocks"))
+			goto found;
+
+		/* BSC on r8a73a4/sh73a0 uses zb_clk instead of an mstp clock */
+		if (of_node_name_eq(clkspec.np, "zb_clk"))
+			goto found;
+
+		of_node_put(clkspec.np);
+		i++;
+	}
+
+	return 0;
+
+found:
+	clk = of_clk_get_from_provider(&clkspec);
+	of_node_put(clkspec.np);
+
+	if (IS_ERR(clk))
+		return PTR_ERR(clk);
+
+	error = pm_clk_create(dev);
+	if (error)
+		goto fail_put;
+
+	error = pm_clk_add_clk(dev, clk);
+	if (error)
+		goto fail_destroy;
+
+	return 0;
+
+fail_destroy:
+	pm_clk_destroy(dev);
+fail_put:
+	clk_put(clk);
+	return error;
+}
+
+void cpg_mstp_detach_dev(struct generic_pm_domain *unused, struct device *dev)
+{
+	if (!pm_clk_no_clocks(dev))
+		pm_clk_destroy(dev);
+}
+
+void __init cpg_mstp_add_clk_domain(struct device_node *np)
+{
+	struct generic_pm_domain *pd;
+	u32 ncells;
+
+	if (of_property_read_u32(np, "#power-domain-cells", &ncells)) {
+		pr_warn("%pOF lacks #power-domain-cells\n", np);
+		return;
+	}
+
+	pd = kzalloc(sizeof(*pd), GFP_KERNEL);
+	if (!pd)
+		return;
+
+	pd->name = np->name;
+	pd->flags = GENPD_FLAG_PM_CLK | GENPD_FLAG_ALWAYS_ON |
+		    GENPD_FLAG_ACTIVE_WAKEUP;
+	pd->attach_dev = cpg_mstp_attach_dev;
+	pd->detach_dev = cpg_mstp_detach_dev;
+	pm_genpd_init(pd, &pm_domain_always_on_gov, false);
+
+	of_genpd_add_provider_simple(np, pd);
+}