1 files changed, 294 insertions, 0 deletions
diff --git a/drivers/clk/mvebu/common.c b/drivers/clk/mvebu/common.c
new file mode 100644
index 000000000..785dbede4
--- /dev/null
+++ b/drivers/clk/mvebu/common.c
@@ -0,0 +1,294 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Marvell EBU SoC common clock handling
+ *
+ * Copyright (C) 2012 Marvell
+ *
+ * Gregory CLEMENT <gregory.clement@free-electrons.com>
+ * Sebastian Hesselbarth <sebastian.hesselbarth@gmail.com>
+ * Andrew Lunn <andrew@lunn.ch>
+ *
+ */
+
+#include <linux/kernel.h>
+#include <linux/slab.h>
+#include <linux/clk.h>
+#include <linux/clk-provider.h>
+#include <linux/io.h>
+#include <linux/of.h>
+#include <linux/of_address.h>
+#include <linux/syscore_ops.h>
+
+#include "common.h"
+
+/*
+ * Core Clocks
+ */
+
+#define SSCG_CONF_MODE(reg)	(((reg) >> 16) & 0x3)
+#define SSCG_SPREAD_DOWN	0x0
+#define SSCG_SPREAD_UP		0x1
+#define SSCG_SPREAD_CENTRAL	0x2
+#define SSCG_CONF_LOW(reg)	(((reg) >> 8) & 0xFF)
+#define SSCG_CONF_HIGH(reg)	((reg) & 0xFF)
+
+static struct clk_onecell_data clk_data;
+
+/*
+ * This function can be used by the Kirkwood, the Armada 370, the
+ * Armada XP and the Armada 375 SoC. The name of the function was
+ * chosen following the dt convention: using the first known SoC
+ * compatible with it.
+ */
+u32 kirkwood_fix_sscg_deviation(u32 system_clk)
+{
+	struct device_node *sscg_np = NULL;
+	void __iomem *sscg_map;
+	u32 sscg_reg;
+	s32 low_bound, high_bound;
+	u64 freq_swing_half;
+
+	sscg_np = of_find_node_by_name(NULL, "sscg");
+	if (sscg_np == NULL) {
+		pr_err("cannot get SSCG register node\n");
+		return system_clk;
+	}
+
+	sscg_map = of_iomap(sscg_np, 0);
+	if (sscg_map == NULL) {
+		pr_err("cannot map SSCG register\n");
+		goto out;
+	}
+
+	sscg_reg = readl(sscg_map);
+	high_bound = SSCG_CONF_HIGH(sscg_reg);
+	low_bound = SSCG_CONF_LOW(sscg_reg);
+
+	if ((high_bound - low_bound) <= 0)
+		goto out;
+	/*
+	 * From Marvell engineer we got the following formula (when
+	 * this code was written, the datasheet was erroneous)
+	 * Spread percentage = 1/96 * (H - L) / H
+	 * H = SSCG_High_Boundary
+	 * L = SSCG_Low_Boundary
+	 *
+	 * As the deviation is half of spread then it lead to the
+	 * following formula in the code.
+	 *
+	 * To avoid an overflow and not lose any significant digit in
+	 * the same time we have to use a 64 bit integer.
+	 */
+
+	freq_swing_half = (((u64)high_bound - (u64)low_bound)
+			* (u64)system_clk);
+	do_div(freq_swing_half, (2 * 96 * high_bound));
+
+	switch (SSCG_CONF_MODE(sscg_reg)) {
+	case SSCG_SPREAD_DOWN:
+		system_clk -= freq_swing_half;
+		break;
+	case SSCG_SPREAD_UP:
+		system_clk += freq_swing_half;
+		break;
+	case SSCG_SPREAD_CENTRAL:
+	default:
+		break;
+	}
+
+	iounmap(sscg_map);
+
+out:
+	of_node_put(sscg_np);
+
+	return system_clk;
+}
+
+void __init mvebu_coreclk_setup(struct device_node *np,
+				const struct coreclk_soc_desc *desc)
+{
+	const char *tclk_name = "tclk";
+	const char *cpuclk_name = "cpuclk";
+	void __iomem *base;
+	unsigned long rate;
+	int n;
+
+	base = of_iomap(np, 0);
+	if (WARN_ON(!base))
+		return;
+
+	/* Allocate struct for TCLK, cpu clk, and core ratio clocks */
+	clk_data.clk_num = 2 + desc->num_ratios;
+
+	/* One more clock for the optional refclk */
+	if (desc->get_refclk_freq)
+		clk_data.clk_num += 1;
+
+	clk_data.clks = kcalloc(clk_data.clk_num, sizeof(*clk_data.clks),
+				GFP_KERNEL);
+	if (WARN_ON(!clk_data.clks)) {
+		iounmap(base);
+		return;
+	}
+
+	/* Register TCLK */
+	of_property_read_string_index(np, "clock-output-names", 0,
+				      &tclk_name);
+	rate = desc->get_tclk_freq(base);
+	clk_data.clks[0] = clk_register_fixed_rate(NULL, tclk_name, NULL, 0,
+						   rate);
+	WARN_ON(IS_ERR(clk_data.clks[0]));
+
+	/* Register CPU clock */
+	of_property_read_string_index(np, "clock-output-names", 1,
+				      &cpuclk_name);
+	rate = desc->get_cpu_freq(base);
+
+	if (desc->is_sscg_enabled && desc->fix_sscg_deviation
+		&& desc->is_sscg_enabled(base))
+		rate = desc->fix_sscg_deviation(rate);
+
+	clk_data.clks[1] = clk_register_fixed_rate(NULL, cpuclk_name, NULL, 0,
+						   rate);
+	WARN_ON(IS_ERR(clk_data.clks[1]));
+
+	/* Register fixed-factor clocks derived from CPU clock */
+	for (n = 0; n < desc->num_ratios; n++) {
+		const char *rclk_name = desc->ratios[n].name;
+		int mult, div;
+
+		of_property_read_string_index(np, "clock-output-names",
+					      2+n, &rclk_name);
+		desc->get_clk_ratio(base, desc->ratios[n].id, &mult, &div);
+		clk_data.clks[2+n] = clk_register_fixed_factor(NULL, rclk_name,
+				       cpuclk_name, 0, mult, div);
+		WARN_ON(IS_ERR(clk_data.clks[2+n]));
+	}
+
+	/* Register optional refclk */
+	if (desc->get_refclk_freq) {
+		const char *name = "refclk";
+		of_property_read_string_index(np, "clock-output-names",
+					      2 + desc->num_ratios, &name);
+		rate = desc->get_refclk_freq(base);
+		clk_data.clks[2 + desc->num_ratios] =
+			clk_register_fixed_rate(NULL, name, NULL, 0, rate);
+		WARN_ON(IS_ERR(clk_data.clks[2 + desc->num_ratios]));
+	}
+
+	/* SAR register isn't needed anymore */
+	iounmap(base);
+
+	of_clk_add_provider(np, of_clk_src_onecell_get, &clk_data);
+}
+
+/*
+ * Clock Gating Control
+ */
+
+DEFINE_SPINLOCK(ctrl_gating_lock);
+
+struct clk_gating_ctrl {
+	spinlock_t *lock;
+	struct clk **gates;
+	int num_gates;
+	void __iomem *base;
+	u32 saved_reg;
+};
+
+static struct clk_gating_ctrl *ctrl;
+
+static struct clk *clk_gating_get_src(
+	struct of_phandle_args *clkspec, void *data)
+{
+	int n;
+
+	if (clkspec->args_count < 1)
+		return ERR_PTR(-EINVAL);
+
+	for (n = 0; n < ctrl->num_gates; n++) {
+		struct clk_gate *gate =
+			to_clk_gate(__clk_get_hw(ctrl->gates[n]));
+		if (clkspec->args[0] == gate->bit_idx)
+			return ctrl->gates[n];
+	}
+	return ERR_PTR(-ENODEV);
+}
+
+static int mvebu_clk_gating_suspend(void)
+{
+	ctrl->saved_reg = readl(ctrl->base);
+	return 0;
+}
+
+static void mvebu_clk_gating_resume(void)
+{
+	writel(ctrl->saved_reg, ctrl->base);
+}
+
+static struct syscore_ops clk_gate_syscore_ops = {
+	.suspend = mvebu_clk_gating_suspend,
+	.resume = mvebu_clk_gating_resume,
+};
+
+void __init mvebu_clk_gating_setup(struct device_node *np,
+				   const struct clk_gating_soc_desc *desc)
+{
+	struct clk *clk;
+	void __iomem *base;
+	const char *default_parent = NULL;
+	int n;
+
+	if (ctrl) {
+		pr_err("mvebu-clk-gating: cannot instantiate more than one gateable clock device\n");
+		return;
+	}
+
+	base = of_iomap(np, 0);
+	if (WARN_ON(!base))
+		return;
+
+	clk = of_clk_get(np, 0);
+	if (!IS_ERR(clk)) {
+		default_parent = __clk_get_name(clk);
+		clk_put(clk);
+	}
+
+	ctrl = kzalloc(sizeof(*ctrl), GFP_KERNEL);
+	if (WARN_ON(!ctrl))
+		goto ctrl_out;
+
+	/* lock must already be initialized */
+	ctrl->lock = &ctrl_gating_lock;
+
+	ctrl->base = base;
+
+	/* Count, allocate, and register clock gates */
+	for (n = 0; desc[n].name;)
+		n++;
+
+	ctrl->num_gates = n;
+	ctrl->gates = kcalloc(ctrl->num_gates, sizeof(*ctrl->gates),
+			      GFP_KERNEL);
+	if (WARN_ON(!ctrl->gates))
+		goto gates_out;
+
+	for (n = 0; n < ctrl->num_gates; n++) {
+		const char *parent =
+			(desc[n].parent) ? desc[n].parent : default_parent;
+		ctrl->gates[n] = clk_register_gate(NULL, desc[n].name, parent,
+					desc[n].flags, base, desc[n].bit_idx,
+					0, ctrl->lock);
+		WARN_ON(IS_ERR(ctrl->gates[n]));
+	}
+
+	of_clk_add_provider(np, clk_gating_get_src, ctrl);
+
+	register_syscore_ops(&clk_gate_syscore_ops);
+
+	return;
+gates_out:
+	kfree(ctrl);
+ctrl_out:
+	iounmap(base);
+}