Merge branch 'mvebu/soc-cpufreq' into mvebu/soc

Documentation/devicetree/bindings/clock/mvebu-cpu-clock.txt

@@ -3,14 +3,15 @@ Device Tree Clock bindings for cpu clock of Marvell EBU platforms
 Required properties:
 - compatible : shall be one of the following:
 	"marvell,armada-xp-cpu-clock" - cpu clocks for Armada XP
-- reg : Address and length of the clock complex register set
+- reg : Address and length of the clock complex register set, followed
+        by address and length of the PMU DFS registers
 - #clock-cells : should be set to 1.
 - clocks : shall be the input parent clock phandle for the clock.
 
 cpuclk: clock-complex@d0018700 {
 	#clock-cells = <1>;
 	compatible = "marvell,armada-xp-cpu-clock";
-	reg = <0xd0018700 0xA0>;
+	reg = <0xd0018700 0xA0>, <0x1c054 0x10>;
 	clocks = <&coreclk 1>;
 }
 

arch/arm/mach-mvebu/platsmp.c

@@ -67,6 +67,7 @@ static void __init set_secondary_cpus_clock(void)
 		if (!cpu_clk)
 			return;
 		clk_set_rate(cpu_clk, rate);
+		clk_prepare_enable(cpu_clk);
 	}
 }
 

arch/arm/mach-mvebu/pmsu.c

@@ -18,20 +18,26 @@
 
 #define pr_fmt(fmt) "mvebu-pmsu: " fmt
 
+#include <linux/clk.h>
 #include <linux/cpu_pm.h>
+#include <linux/delay.h>
 #include <linux/kernel.h>
 #include <linux/init.h>
 #include <linux/of_address.h>
+#include <linux/of_device.h>
 #include <linux/io.h>
 #include <linux/platform_device.h>
+#include <linux/pm_opp.h>
 #include <linux/smp.h>
 #include <linux/resource.h>
+#include <linux/slab.h>
 #include <asm/cacheflush.h>
 #include <asm/cp15.h>
 #include <asm/smp_plat.h>
 #include <asm/suspend.h>
 #include <asm/tlbflush.h>
 #include "common.h"
+#include "armada-370-xp.h"
 
 static void __iomem *pmsu_mp_base;
 
@@ -57,6 +63,10 @@ static void __iomem *pmsu_mp_base;
 #define PMSU_STATUS_AND_MASK_IRQ_MASK		BIT(24)
 #define PMSU_STATUS_AND_MASK_FIQ_MASK		BIT(25)
 
+#define PMSU_EVENT_STATUS_AND_MASK(cpu)     ((cpu * 0x100) + 0x120)
+#define PMSU_EVENT_STATUS_AND_MASK_DFS_DONE        BIT(1)
+#define PMSU_EVENT_STATUS_AND_MASK_DFS_DONE_MASK   BIT(17)
+
 #define PMSU_BOOT_ADDR_REDIRECT_OFFSET(cpu) ((cpu * 0x100) + 0x124)
 
 /* PMSU fabric registers */
@@ -291,3 +301,155 @@ static int __init armada_370_xp_cpu_pm_init(void)
 
 arch_initcall(armada_370_xp_cpu_pm_init);
 early_initcall(armada_370_xp_pmsu_init);
+
+static void mvebu_pmsu_dfs_request_local(void *data)
+{
+	u32 reg;
+	u32 cpu = smp_processor_id();
+	unsigned long flags;
+
+	local_irq_save(flags);
+
+	/* Prepare to enter idle */
+	reg = readl(pmsu_mp_base + PMSU_STATUS_AND_MASK(cpu));
+	reg |= PMSU_STATUS_AND_MASK_CPU_IDLE_WAIT |
+	       PMSU_STATUS_AND_MASK_IRQ_MASK     |
+	       PMSU_STATUS_AND_MASK_FIQ_MASK;
+	writel(reg, pmsu_mp_base + PMSU_STATUS_AND_MASK(cpu));
+
+	/* Request the DFS transition */
+	reg = readl(pmsu_mp_base + PMSU_CONTROL_AND_CONFIG(cpu));
+	reg |= PMSU_CONTROL_AND_CONFIG_DFS_REQ;
+	writel(reg, pmsu_mp_base + PMSU_CONTROL_AND_CONFIG(cpu));
+
+	/* The fact of entering idle will trigger the DFS transition */
+	wfi();
+
+	/*
+	 * We're back from idle, the DFS transition has completed,
+	 * clear the idle wait indication.
+	 */
+	reg = readl(pmsu_mp_base + PMSU_STATUS_AND_MASK(cpu));
+	reg &= ~PMSU_STATUS_AND_MASK_CPU_IDLE_WAIT;
+	writel(reg, pmsu_mp_base + PMSU_STATUS_AND_MASK(cpu));
+
+	local_irq_restore(flags);
+}
+
+int mvebu_pmsu_dfs_request(int cpu)
+{
+	unsigned long timeout;
+	int hwcpu = cpu_logical_map(cpu);
+	u32 reg;
+
+	/* Clear any previous DFS DONE event */
+	reg = readl(pmsu_mp_base + PMSU_EVENT_STATUS_AND_MASK(hwcpu));
+	reg &= ~PMSU_EVENT_STATUS_AND_MASK_DFS_DONE;
+	writel(reg, pmsu_mp_base + PMSU_EVENT_STATUS_AND_MASK(hwcpu));
+
+	/* Mask the DFS done interrupt, since we are going to poll */
+	reg = readl(pmsu_mp_base + PMSU_EVENT_STATUS_AND_MASK(hwcpu));
+	reg |= PMSU_EVENT_STATUS_AND_MASK_DFS_DONE_MASK;
+	writel(reg, pmsu_mp_base + PMSU_EVENT_STATUS_AND_MASK(hwcpu));
+
+	/* Trigger the DFS on the appropriate CPU */
+	smp_call_function_single(cpu, mvebu_pmsu_dfs_request_local,
+				 NULL, false);
+
+	/* Poll until the DFS done event is generated */
+	timeout = jiffies + HZ;
+	while (time_before(jiffies, timeout)) {
+		reg = readl(pmsu_mp_base + PMSU_EVENT_STATUS_AND_MASK(hwcpu));
+		if (reg & PMSU_EVENT_STATUS_AND_MASK_DFS_DONE)
+			break;
+		udelay(10);
+	}
+
+	if (time_after(jiffies, timeout))
+		return -ETIME;
+
+	/* Restore the DFS mask to its original state */
+	reg = readl(pmsu_mp_base + PMSU_EVENT_STATUS_AND_MASK(hwcpu));
+	reg &= ~PMSU_EVENT_STATUS_AND_MASK_DFS_DONE_MASK;
+	writel(reg, pmsu_mp_base + PMSU_EVENT_STATUS_AND_MASK(hwcpu));
+
+	return 0;
+}
+
+static int __init armada_xp_pmsu_cpufreq_init(void)
+{
+	struct device_node *np;
+	struct resource res;
+	int ret, cpu;
+
+	if (!of_machine_is_compatible("marvell,armadaxp"))
+		return 0;
+
+	/*
+	 * In order to have proper cpufreq handling, we need to ensure
+	 * that the Device Tree description of the CPU clock includes
+	 * the definition of the PMU DFS registers. If not, we do not
+	 * register the clock notifier and the cpufreq driver. This
+	 * piece of code is only for compatibility with old Device
+	 * Trees.
+	 */
+	np = of_find_compatible_node(NULL, NULL, "marvell,armada-xp-cpu-clock");
+	if (!np)
+		return 0;
+
+	ret = of_address_to_resource(np, 1, &res);
+	if (ret) {
+		pr_warn(FW_WARN "not enabling cpufreq, deprecated armada-xp-cpu-clock binding\n");
+		of_node_put(np);
+		return 0;
+	}
+
+	of_node_put(np);
+
+	/*
+	 * For each CPU, this loop registers the operating points
+	 * supported (which are the nominal CPU frequency and half of
+	 * it), and registers the clock notifier that will take care
+	 * of doing the PMSU part of a frequency transition.
+	 */
+	for_each_possible_cpu(cpu) {
+		struct device *cpu_dev;
+		struct clk *clk;
+		int ret;
+
+		cpu_dev = get_cpu_device(cpu);
+		if (!cpu_dev) {
+			pr_err("Cannot get CPU %d\n", cpu);
+			continue;
+		}
+
+		clk = clk_get(cpu_dev, 0);
+		if (!clk) {
+			pr_err("Cannot get clock for CPU %d\n", cpu);
+			return -ENODEV;
+		}
+
+		/*
+		 * In case of a failure of dev_pm_opp_add(), we don't
+		 * bother with cleaning up the registered OPP (there's
+		 * no function to do so), and simply cancel the
+		 * registration of the cpufreq device.
+		 */
+		ret = dev_pm_opp_add(cpu_dev, clk_get_rate(clk), 0);
+		if (ret) {
+			clk_put(clk);
+			return ret;
+		}
+
+		ret = dev_pm_opp_add(cpu_dev, clk_get_rate(clk) / 2, 0);
+		if (ret) {
+			clk_put(clk);
+			return ret;
+		}
+	}
+
+	platform_device_register_simple("cpufreq-generic", -1, NULL, 0);
+	return 0;
+}
+
+device_initcall(armada_xp_pmsu_cpufreq_init);

drivers/clk/mvebu/clk-cpu.c

@@ -16,11 +16,20 @@
 #include <linux/io.h>
 #include <linux/of.h>
 #include <linux/delay.h>
+#include <linux/mvebu-pmsu.h>
+#include <asm/smp_plat.h>
 
 #define SYS_CTRL_CLK_DIVIDER_CTRL_OFFSET               0x0
+#define   SYS_CTRL_CLK_DIVIDER_CTRL_RESET_ALL          0xff
+#define   SYS_CTRL_CLK_DIVIDER_CTRL_RESET_SHIFT        8
+#define SYS_CTRL_CLK_DIVIDER_CTRL2_OFFSET              0x8
+#define   SYS_CTRL_CLK_DIVIDER_CTRL2_NBCLK_RATIO_SHIFT 16
 #define SYS_CTRL_CLK_DIVIDER_VALUE_OFFSET              0xC
 #define SYS_CTRL_CLK_DIVIDER_MASK                      0x3F
 
+#define PMU_DFS_RATIO_SHIFT 16
+#define PMU_DFS_RATIO_MASK  0x3F
+
 #define MAX_CPU	    4
 struct cpu_clk {
 	struct clk_hw hw;
@@ -28,6 +37,7 @@ struct cpu_clk {
 	const char *clk_name;
 	const char *parent_name;
 	void __iomem *reg_base;
+	void __iomem *pmu_dfs;
 };
 
 static struct clk **clks;
@@ -62,8 +72,9 @@ static long clk_cpu_round_rate(struct clk_hw *hwclk, unsigned long rate,
 	return *parent_rate / div;
 }
 
-static int clk_cpu_set_rate(struct clk_hw *hwclk, unsigned long rate,
+static int clk_cpu_off_set_rate(struct clk_hw *hwclk, unsigned long rate,
 				unsigned long parent_rate)
+
 {
 	struct cpu_clk *cpuclk = to_cpu_clk(hwclk);
 	u32 reg, div;
@@ -95,6 +106,58 @@ static int clk_cpu_set_rate(struct clk_hw *hwclk, unsigned long rate,
 	return 0;
 }
 
+static int clk_cpu_on_set_rate(struct clk_hw *hwclk, unsigned long rate,
+			       unsigned long parent_rate)
+{
+	u32 reg;
+	unsigned long fabric_div, target_div, cur_rate;
+	struct cpu_clk *cpuclk = to_cpu_clk(hwclk);
+
+	/*
+	 * PMU DFS registers are not mapped, Device Tree does not
+	 * describes them. We cannot change the frequency dynamically.
+	 */
+	if (!cpuclk->pmu_dfs)
+		return -ENODEV;
+
+	cur_rate = __clk_get_rate(hwclk->clk);
+
+	reg = readl(cpuclk->reg_base + SYS_CTRL_CLK_DIVIDER_CTRL2_OFFSET);
+	fabric_div = (reg >> SYS_CTRL_CLK_DIVIDER_CTRL2_NBCLK_RATIO_SHIFT) &
+		SYS_CTRL_CLK_DIVIDER_MASK;
+
+	/* Frequency is going up */
+	if (rate == 2 * cur_rate)
+		target_div = fabric_div / 2;
+	/* Frequency is going down */
+	else
+		target_div = fabric_div;
+
+	if (target_div == 0)
+		target_div = 1;
+
+	reg = readl(cpuclk->pmu_dfs);
+	reg &= ~(PMU_DFS_RATIO_MASK << PMU_DFS_RATIO_SHIFT);
+	reg |= (target_div << PMU_DFS_RATIO_SHIFT);
+	writel(reg, cpuclk->pmu_dfs);
+
+	reg = readl(cpuclk->reg_base + SYS_CTRL_CLK_DIVIDER_CTRL_OFFSET);
+	reg |= (SYS_CTRL_CLK_DIVIDER_CTRL_RESET_ALL <<
+		SYS_CTRL_CLK_DIVIDER_CTRL_RESET_SHIFT);
+	writel(reg, cpuclk->reg_base + SYS_CTRL_CLK_DIVIDER_CTRL_OFFSET);
+
+	return mvebu_pmsu_dfs_request(cpuclk->cpu);
+}
+
+static int clk_cpu_set_rate(struct clk_hw *hwclk, unsigned long rate,
+			    unsigned long parent_rate)
+{
+	if (__clk_is_enabled(hwclk->clk))
+		return clk_cpu_on_set_rate(hwclk, rate, parent_rate);
+	else
+		return clk_cpu_off_set_rate(hwclk, rate, parent_rate);
+}
+
 static const struct clk_ops cpu_ops = {
 	.recalc_rate = clk_cpu_recalc_rate,
 	.round_rate = clk_cpu_round_rate,
@@ -105,6 +168,7 @@ static void __init of_cpu_clk_setup(struct device_node *node)
 {
 	struct cpu_clk *cpuclk;
 	void __iomem *clock_complex_base = of_iomap(node, 0);
+	void __iomem *pmu_dfs_base = of_iomap(node, 1);
 	int ncpus = 0;
 	struct device_node *dn;
 
@@ -114,6 +178,10 @@ static void __init of_cpu_clk_setup(struct device_node *node)
 		return;
 	}
 
+	if (pmu_dfs_base == NULL)
+		pr_warn("%s: pmu-dfs base register not set, dynamic frequency scaling not available\n",
+			__func__);
+
 	for_each_node_by_type(dn, "cpu")
 		ncpus++;
 
@@ -146,6 +214,8 @@ static void __init of_cpu_clk_setup(struct device_node *node)
 		cpuclk[cpu].clk_name = clk_name;
 		cpuclk[cpu].cpu = cpu;
 		cpuclk[cpu].reg_base = clock_complex_base;
+		if (pmu_dfs_base)
+			cpuclk[cpu].pmu_dfs = pmu_dfs_base + 4 * cpu;
 		cpuclk[cpu].hw.init = &init;
 
 		init.name = cpuclk[cpu].clk_name;

include/linux/mvebu-pmsu.h

@@ -0,0 +1,20 @@
+/*
+ * Copyright (C) 2012 Marvell
+ *
+ * Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
+ *
+ * This file is licensed under the terms of the GNU General Public
+ * License version 2.  This program is licensed "as is" without any
+ * warranty of any kind, whether express or implied.
+ */
+
+#ifndef __MVEBU_PMSU_H__
+#define __MVEBU_PMSU_H__
+
+#ifdef CONFIG_MACH_MVEBU_V7
+int mvebu_pmsu_dfs_request(int cpu);
+#else
+static inline int mvebu_pmsu_dfs_request(int cpu) { return -ENODEV; }
+#endif
+
+#endif /* __MVEBU_PMSU_H__ */