[PATCH] ARM: 2803/1: OMAP update 11/11: Add cpufreq support

Patch from Tony Lindgren

This patch adds minimal cpufreq support for OMAP
taking advantage of the clock framework.

Signed-off-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

1 files changed, 128 insertions, 0 deletions

diff --git a/arch/arm/plat-omap/cpu-omap.c b/arch/arm/plat-omap/cpu-omap.c
new file mode 100644
index 000000000000..409aac2c4b9d
--- /dev/null
+++ b/arch/arm/plat-omap/cpu-omap.c
@@ -0,0 +1,128 @@
+/*
+ *  linux/arch/arm/plat-omap/cpu-omap.c
+ *
+ *  CPU frequency scaling for OMAP
+ *
+ *  Copyright (C) 2005 Nokia Corporation
+ *  Written by Tony Lindgren <tony@atomide.com>
+ *
+ *  Based on cpu-sa1110.c, Copyright (C) 2001 Russell King
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+#include <linux/types.h>
+#include <linux/kernel.h>
+#include <linux/sched.h>
+#include <linux/cpufreq.h>
+#include <linux/delay.h>
+#include <linux/init.h>
+#include <linux/err.h>
+
+#include <asm/hardware.h>
+#include <asm/mach-types.h>
+#include <asm/io.h>
+#include <asm/system.h>
+
+#include <asm/hardware/clock.h>
+
+/* TODO: Add support for SDRAM timing changes */
+
+int omap_verify_speed(struct cpufreq_policy *policy)
+{
+        struct clk * mpu_clk;
+
+        if (policy->cpu)
+                return -EINVAL;
+
+        cpufreq_verify_within_limits(policy, policy->cpuinfo.min_freq,
+                                     policy->cpuinfo.max_freq);
+        mpu_clk = clk_get(NULL, "mpu");
+        if (IS_ERR(mpu_clk))
+                return PTR_ERR(mpu_clk);
+        policy->min = clk_round_rate(mpu_clk, policy->min * 1000) / 1000;
+        policy->max = clk_round_rate(mpu_clk, policy->max * 1000) / 1000;
+        cpufreq_verify_within_limits(policy, policy->cpuinfo.min_freq,
+                                     policy->cpuinfo.max_freq);
+        clk_put(mpu_clk);
+
+        return 0;
+}
+
+unsigned int omap_getspeed(unsigned int cpu)
+{
+        struct clk * mpu_clk;
+        unsigned long rate;
+
+        if (cpu)
+                return 0;
+
+        mpu_clk = clk_get(NULL, "mpu");
+        if (IS_ERR(mpu_clk))
+                return 0;
+        rate = clk_get_rate(mpu_clk) / 1000;
+        clk_put(mpu_clk);
+
+        return rate;
+}
+
+static int omap_target(struct cpufreq_policy *policy,
+                       unsigned int target_freq,
+                       unsigned int relation)
+{
+        struct clk * mpu_clk;
+        struct cpufreq_freqs freqs;
+        int ret = 0;
+
+        mpu_clk = clk_get(NULL, "mpu");
+        if (IS_ERR(mpu_clk))
+                return PTR_ERR(mpu_clk);
+
+        freqs.old = omap_getspeed(0);
+        freqs.new = clk_round_rate(mpu_clk, target_freq * 1000) / 1000;
+        freqs.cpu = 0;
+
+        cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE);
+        ret = clk_set_rate(mpu_clk, target_freq * 1000);
+        cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE);
+        clk_put(mpu_clk);
+
+        return ret;
+}
+
+static int __init omap_cpu_init(struct cpufreq_policy *policy)
+{
+        struct clk * mpu_clk;
+
+        mpu_clk = clk_get(NULL, "mpu");
+        if (IS_ERR(mpu_clk))
+                return PTR_ERR(mpu_clk);
+
+        if (policy->cpu != 0)
+                return -EINVAL;
+        policy->cur = policy->min = policy->max = omap_getspeed(0);
+        policy->governor = CPUFREQ_DEFAULT_GOVERNOR;
+        policy->cpuinfo.min_freq = clk_round_rate(mpu_clk, 0) / 1000;
+        policy->cpuinfo.max_freq = clk_round_rate(mpu_clk, 216000000) / 1000;
+        policy->cpuinfo.transition_latency = CPUFREQ_ETERNAL;
+        clk_put(mpu_clk);
+
+        return 0;
+}
+
+static struct cpufreq_driver omap_driver = {
+        .flags          = CPUFREQ_STICKY,
+        .verify         = omap_verify_speed,
+        .target         = omap_target,
+        .get            = omap_getspeed,
+        .init           = omap_cpu_init,
+        .name           = "omap",
+};
+
+static int __init omap_cpufreq_init(void)
+{
+        return cpufreq_register_driver(&omap_driver);
+}
+
+arch_initcall(omap_cpufreq_init);