8 files changed, 43 insertions, 19 deletions

diff --git a/arch/arm/mach-imx/clk-imx27.c b/arch/arm/mach-imx/clk-imx27.c
index c3cfa4116dc0..c6b40f386786 100644
--- a/arch/arm/mach-imx/clk-imx27.c
+++ b/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);
diff --git a/arch/arm/mach-imx/clk-imx51-imx53.c b/arch/arm/mach-imx/clk-imx51-imx53.c
index 1a56a3319997..de1964c7b8bc 100644
--- a/arch/arm/mach-imx/clk-imx51-imx53.c
+++ b/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");
diff --git a/arch/arm/mach-imx/mach-imx6q.c b/arch/arm/mach-imx/mach-imx6q.c
index 85a1b51346c8..90372a21087f 100644
--- a/arch/arm/mach-imx/mach-imx6q.c
+++ b/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);
         }
 }
diff --git a/arch/arm/mach-shmobile/clock-r8a73a4.c b/arch/arm/mach-shmobile/clock-r8a73a4.c
index 8ea5ef6c79cc..5bd2e851e3c7 100644
--- a/arch/arm/mach-shmobile/clock-r8a73a4.c
+++ b/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]),
diff --git a/arch/arm/mach-shmobile/clock-sh73a0.c b/arch/arm/mach-shmobile/clock-sh73a0.c
index 1942eaef5181..c92c023f0d27 100644
--- a/arch/arm/mach-shmobile/clock-sh73a0.c
+++ b/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]),
diff --git a/drivers/cpufreq/cpufreq-cpu0.c b/drivers/cpufreq/cpufreq-cpu0.c
index cbfffa91ebdd..78c49d8e0f4a 100644
--- a/drivers/cpufreq/cpufreq-cpu0.c
+++ b/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) {
diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c
index 43c24aa756f6..89b3c52cd5c3 100644
--- a/drivers/cpufreq/cpufreq.c
+++ b/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);
diff --git a/drivers/cpufreq/imx6q-cpufreq.c b/drivers/cpufreq/imx6q-cpufreq.c
index 3e396543aea4..c3fd2a101ca0 100644
--- a/drivers/cpufreq/imx6q-cpufreq.c
+++ b/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) {