Merge branch 'pm-cpufreq'

* pm-cpufreq:
  cpufreq: return EEXIST instead of EBUSY for second registering
  ARM: shmobile: change dev_id to cpu0 while registering cpu clock
  ARM: i.MX: change dev_id to cpu0 while registering cpu clock
  cpufreq: imx6q-cpufreq: assign cpu_dev correctly to cpu0 device
  cpufreq: cpufreq-cpu0: assign cpu_dev correctly to cpu0 device
  cpufreq: unlock correct rwsem while updating policy->cpu
  cpufreq: Clear policy->cpus bits in __cpufreq_remove_dev_finish()

arch/arm/mach-imx/clk-imx27.c

@@ -285,7 +285,7 @@ int __init mx27_clocks_init(unsigned long fref)
 	clk_register_clkdev(clk[ata_ahb_gate], "ata", NULL);
 	clk_register_clkdev(clk[rtc_ipg_gate], NULL, "imx21-rtc");
 	clk_register_clkdev(clk[scc_ipg_gate], "scc", NULL);
-	clk_register_clkdev(clk[cpu_div], NULL, "cpufreq-cpu0.0");
+	clk_register_clkdev(clk[cpu_div], NULL, "cpu0");
 	clk_register_clkdev(clk[emi_ahb_gate], "emi_ahb" , NULL);
 
 	mxc_timer_init(MX27_IO_ADDRESS(MX27_GPT1_BASE_ADDR), MX27_INT_GPT1);

arch/arm/mach-imx/clk-imx51-imx53.c

@@ -328,7 +328,7 @@ static void __init mx5_clocks_common_init(unsigned long rate_ckil,
 	clk_register_clkdev(clk[ssi2_ipg_gate], NULL, "imx-ssi.1");
 	clk_register_clkdev(clk[ssi3_ipg_gate], NULL, "imx-ssi.2");
 	clk_register_clkdev(clk[sdma_gate], NULL, "imx35-sdma");
-	clk_register_clkdev(clk[cpu_podf], NULL, "cpufreq-cpu0.0");
+	clk_register_clkdev(clk[cpu_podf], NULL, "cpu0");
 	clk_register_clkdev(clk[iim_gate], "iim", NULL);
 	clk_register_clkdev(clk[dummy], NULL, "imx2-wdt.0");
 	clk_register_clkdev(clk[dummy], NULL, "imx2-wdt.1");

arch/arm/mach-imx/mach-imx6q.c

@@ -233,10 +233,15 @@ put_node:
 	of_node_put(np);
 }
 
-static void __init imx6q_opp_init(struct device *cpu_dev)
+static void __init imx6q_opp_init(void)
 {
 	struct device_node *np;
+	struct device *cpu_dev = get_cpu_device(0);
 
+	if (!cpu_dev) {
+		pr_warn("failed to get cpu0 device\n");
+		return;
+	}
 	np = of_node_get(cpu_dev->of_node);
 	if (!np) {
 		pr_warn("failed to find cpu0 node\n");
@@ -268,7 +273,7 @@ static void __init imx6q_init_late(void)
 		imx6q_cpuidle_init();
 
 	if (IS_ENABLED(CONFIG_ARM_IMX6Q_CPUFREQ)) {
-		imx6q_opp_init(&imx6q_cpufreq_pdev.dev);
+		imx6q_opp_init();
 		platform_device_register(&imx6q_cpufreq_pdev);
 	}
 }

arch/arm/mach-shmobile/clock-r8a73a4.c

@@ -555,7 +555,7 @@ static struct clk_lookup lookups[] = {
 	CLKDEV_CON_ID("pll2h",			&pll2h_clk),
 
 	/* CPU clock */
-	CLKDEV_DEV_ID("cpufreq-cpu0",		&z_clk),
+	CLKDEV_DEV_ID("cpu0",			&z_clk),
 
 	/* DIV6 */
 	CLKDEV_CON_ID("zb",			&div6_clks[DIV6_ZB]),

arch/arm/mach-shmobile/clock-sh73a0.c

@@ -616,7 +616,7 @@ static struct clk_lookup lookups[] = {
 	CLKDEV_DEV_ID("smp_twd", &twd_clk), /* smp_twd */
 
 	/* DIV4 clocks */
-	CLKDEV_DEV_ID("cpufreq-cpu0", &div4_clks[DIV4_Z]),
+	CLKDEV_DEV_ID("cpu0", &div4_clks[DIV4_Z]),
 
 	/* DIV6 clocks */
 	CLKDEV_CON_ID("vck1_clk", &div6_clks[DIV6_VCK1]),

drivers/cpufreq/cpufreq-cpu0.c

@@ -12,6 +12,7 @@
 #define pr_fmt(fmt)	KBUILD_MODNAME ": " fmt
 
 #include <linux/clk.h>
+#include <linux/cpu.h>
 #include <linux/cpufreq.h>
 #include <linux/err.h>
 #include <linux/module.h>
@@ -177,7 +178,11 @@ static int cpu0_cpufreq_probe(struct platform_device *pdev)
 	struct device_node *np;
 	int ret;
 
-	cpu_dev = &pdev->dev;
+	cpu_dev = get_cpu_device(0);
+	if (!cpu_dev) {
+		pr_err("failed to get cpu0 device\n");
+		return -ENODEV;
+	}
 
 	np = of_node_get(cpu_dev->of_node);
 	if (!np) {

drivers/cpufreq/cpufreq.c

@@ -952,9 +952,20 @@ static void update_policy_cpu(struct cpufreq_policy *policy, unsigned int cpu)
 	if (cpu == policy->cpu)
 		return;
 
+	/*
+	 * Take direct locks as lock_policy_rwsem_write wouldn't work here.
+	 * Also lock for last cpu is enough here as contention will happen only
+	 * after policy->cpu is changed and after it is changed, other threads
+	 * will try to acquire lock for new cpu. And policy is already updated
+	 * by then.
+	 */
+	down_write(&per_cpu(cpu_policy_rwsem, policy->cpu));
+
 	policy->last_cpu = policy->cpu;
 	policy->cpu = cpu;
 
+	up_write(&per_cpu(cpu_policy_rwsem, policy->last_cpu));
+
 #ifdef CONFIG_CPU_FREQ_TABLE
 	cpufreq_frequency_table_update_policy_cpu(policy);
 #endif
@@ -1125,7 +1136,7 @@ static int cpufreq_nominate_new_policy_cpu(struct cpufreq_policy *policy,
 	int ret;
 
 	/* first sibling now owns the new sysfs dir */
-	cpu_dev = get_cpu_device(cpumask_first(policy->cpus));
+	cpu_dev = get_cpu_device(cpumask_any_but(policy->cpus, old_cpu));
 
 	/* Don't touch sysfs files during light-weight tear-down */
 	if (frozen)
@@ -1189,12 +1200,9 @@ static int __cpufreq_remove_dev_prepare(struct device *dev,
 			policy->governor->name, CPUFREQ_NAME_LEN);
 #endif
 
-	WARN_ON(lock_policy_rwsem_write(cpu));
+	lock_policy_rwsem_read(cpu);
 	cpus = cpumask_weight(policy->cpus);
-
-	if (cpus > 1)
-		cpumask_clear_cpu(cpu, policy->cpus);
-	unlock_policy_rwsem_write(cpu);
+	unlock_policy_rwsem_read(cpu);
 
 	if (cpu != policy->cpu) {
 		if (!frozen)
@@ -1203,9 +1211,7 @@ static int __cpufreq_remove_dev_prepare(struct device *dev,
 
 		new_cpu = cpufreq_nominate_new_policy_cpu(policy, cpu, frozen);
 		if (new_cpu >= 0) {
-			WARN_ON(lock_policy_rwsem_write(cpu));
 			update_policy_cpu(policy, new_cpu);
-			unlock_policy_rwsem_write(cpu);
 
 			if (!frozen) {
 				pr_debug("%s: policy Kobject moved to cpu: %d "
@@ -1237,9 +1243,12 @@ static int __cpufreq_remove_dev_finish(struct device *dev,
 		return -EINVAL;
 	}
 
-	lock_policy_rwsem_read(cpu);
+	WARN_ON(lock_policy_rwsem_write(cpu));
 	cpus = cpumask_weight(policy->cpus);
-	unlock_policy_rwsem_read(cpu);
+
+	if (cpus > 1)
+		cpumask_clear_cpu(cpu, policy->cpus);
+	unlock_policy_rwsem_write(cpu);
 
 	/* If cpu is last user of policy, free policy */
 	if (cpus == 1) {
@@ -2095,7 +2104,7 @@ int cpufreq_register_driver(struct cpufreq_driver *driver_data)
 	write_lock_irqsave(&cpufreq_driver_lock, flags);
 	if (cpufreq_driver) {
 		write_unlock_irqrestore(&cpufreq_driver_lock, flags);
-		return -EBUSY;
+		return -EEXIST;
 	}
 	cpufreq_driver = driver_data;
 	write_unlock_irqrestore(&cpufreq_driver_lock, flags);

drivers/cpufreq/imx6q-cpufreq.c

@@ -7,6 +7,7 @@
  */
 
 #include <linux/clk.h>
+#include <linux/cpu.h>
 #include <linux/cpufreq.h>
 #include <linux/delay.h>
 #include <linux/err.h>
@@ -202,7 +203,11 @@ static int imx6q_cpufreq_probe(struct platform_device *pdev)
 	unsigned long min_volt, max_volt;
 	int num, ret;
 
-	cpu_dev = &pdev->dev;
+	cpu_dev = get_cpu_device(0);
+	if (!cpu_dev) {
+		pr_err("failed to get cpu0 device\n");
+		return -ENODEV;
+	}
 
 	np = of_node_get(cpu_dev->of_node);
 	if (!np) {