cpufreq: OMAP: cleanup for multi-SoC support, move into drivers/cpufreq

Move OMAP cpufreq driver from arch/arm/mach-omap2 into
drivers/cpufreq, along with a few cleanups:

- generalize support for better handling of different SoCs in the OMAP
- use OPP layer instead of OMAP clock internals for frequency table init

Signed-off-by: Santosh Shilimkar <santosh.shilimkar@ti.com>
[khilman@ti.com: move to drivers]
Signed-off-by: Kevin Hilman <khilman@ti.com>

1 files changed, 188 insertions, 0 deletions

diff --git a/drivers/cpufreq/omap-cpufreq.c b/drivers/cpufreq/omap-cpufreq.c
new file mode 100644
index 00000000000..a6b2be7ea5a
--- /dev/null
+++ b/drivers/cpufreq/omap-cpufreq.c
@@ -0,0 +1,188 @@
+/*
+ *  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
+ *
+ * Copyright (C) 2007-2011 Texas Instruments, Inc.
+ * - OMAP3/4 support by Rajendra Nayak, Santosh Shilimkar
+ *
+ * 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 <linux/clk.h>
+#include <linux/io.h>
+#include <linux/opp.h>
+
+#include <asm/system.h>
+#include <asm/smp_plat.h>
+
+#include <plat/clock.h>
+#include <plat/omap-pm.h>
+#include <plat/common.h>
+
+#include <mach/hardware.h>
+
+#define VERY_HI_RATE	900000000
+
+static struct cpufreq_frequency_table *freq_table;
+static struct clk *mpu_clk;
+
+static int omap_verify_speed(struct cpufreq_policy *policy)
+{
+	if (freq_table)
+		return cpufreq_frequency_table_verify(policy, freq_table);
+
+	if (policy->cpu)
+		return -EINVAL;
+
+	cpufreq_verify_within_limits(policy, policy->cpuinfo.min_freq,
+				     policy->cpuinfo.max_freq);
+
+	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);
+	return 0;
+}
+
+static unsigned int omap_getspeed(unsigned int cpu)
+{
+	unsigned long rate;
+
+	if (cpu)
+		return 0;
+
+	rate = clk_get_rate(mpu_clk) / 1000;
+	return rate;
+}
+
+static int omap_target(struct cpufreq_policy *policy,
+		       unsigned int target_freq,
+		       unsigned int relation)
+{
+	int ret = 0;
+	struct cpufreq_freqs freqs;
+
+	/* Ensure desired rate is within allowed range.  Some govenors
+	 * (ondemand) will just pass target_freq=0 to get the minimum. */
+	if (target_freq < policy->min)
+		target_freq = policy->min;
+	if (target_freq > policy->max)
+		target_freq = policy->max;
+
+	freqs.old = omap_getspeed(0);
+	freqs.new = clk_round_rate(mpu_clk, target_freq * 1000) / 1000;
+	freqs.cpu = 0;
+
+	if (freqs.old == freqs.new)
+		return ret;
+
+	cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE);
+
+#ifdef CONFIG_CPU_FREQ_DEBUG
+	pr_info("cpufreq-omap: transition: %u --> %u\n", freqs.old, freqs.new);
+#endif
+
+	ret = clk_set_rate(mpu_clk, freqs.new * 1000);
+
+	cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE);
+
+	return ret;
+}
+
+static int __cpuinit omap_cpu_init(struct cpufreq_policy *policy)
+{
+	int result = 0;
+	struct device *mpu_dev;
+
+	if (cpu_is_omap24xx())
+		mpu_clk = clk_get(NULL, "virt_prcm_set");
+	else if (cpu_is_omap34xx())
+		mpu_clk = clk_get(NULL, "dpll1_ck");
+	else if (cpu_is_omap44xx())
+		mpu_clk = clk_get(NULL, "dpll_mpu_ck");
+
+	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);
+
+	mpu_dev = omap2_get_mpuss_device();
+	if (!mpu_dev) {
+		pr_warning("%s: unable to get the mpu device\n", __func__);
+		return -EINVAL;
+	}
+	opp_init_cpufreq_table(mpu_dev, &freq_table);
+
+	if (freq_table) {
+		result = cpufreq_frequency_table_cpuinfo(policy, freq_table);
+		if (!result)
+			cpufreq_frequency_table_get_attr(freq_table,
+							policy->cpu);
+	} else {
+		policy->cpuinfo.min_freq = clk_round_rate(mpu_clk, 0) / 1000;
+		policy->cpuinfo.max_freq = clk_round_rate(mpu_clk,
+							VERY_HI_RATE) / 1000;
+	}
+
+	policy->min = policy->cpuinfo.min_freq;
+	policy->max = policy->cpuinfo.max_freq;
+	policy->cur = omap_getspeed(0);
+
+	/* FIXME: what's the actual transition time? */
+	policy->cpuinfo.transition_latency = 300 * 1000;
+
+	return 0;
+}
+
+static int omap_cpu_exit(struct cpufreq_policy *policy)
+{
+	clk_exit_cpufreq_table(&freq_table);
+	clk_put(mpu_clk);
+	return 0;
+}
+
+static struct freq_attr *omap_cpufreq_attr[] = {
+	&cpufreq_freq_attr_scaling_available_freqs,
+	NULL,
+};
+
+static struct cpufreq_driver omap_driver = {
+	.flags		= CPUFREQ_STICKY,
+	.verify		= omap_verify_speed,
+	.target		= omap_target,
+	.get		= omap_getspeed,
+	.init		= omap_cpu_init,
+	.exit		= omap_cpu_exit,
+	.name		= "omap",
+	.attr		= omap_cpufreq_attr,
+};
+
+static int __init omap_cpufreq_init(void)
+{
+	return cpufreq_register_driver(&omap_driver);
+}
+
+static void __exit omap_cpufreq_exit(void)
+{
+	cpufreq_unregister_driver(&omap_driver);
+}
+
+MODULE_DESCRIPTION("cpufreq driver for OMAP SoCs");
+MODULE_LICENSE("GPL");
+module_init(omap_cpufreq_init);
+module_exit(omap_cpufreq_exit);