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>

2 files changed, 189 insertions, 0 deletions

diff --git a/drivers/cpufreq/Makefile b/drivers/cpufreq/Makefile
index a48bc02cd765..ce75fcbcca4f 100644
--- a/drivers/cpufreq/Makefile
+++ b/drivers/cpufreq/Makefile
@@ -43,6 +43,7 @@ obj-$(CONFIG_UX500_SOC_DB8500)		+= db8500-cpufreq.o
 obj-$(CONFIG_ARM_S3C64XX_CPUFREQ)       += s3c64xx-cpufreq.o
 obj-$(CONFIG_ARM_S5PV210_CPUFREQ)       += s5pv210-cpufreq.o
 obj-$(CONFIG_ARM_EXYNOS4210_CPUFREQ)    += exynos4210-cpufreq.o
+obj-$(CONFIG_ARCH_OMAP2PLUS)            += omap-cpufreq.o
 
 ##################################################################################
 # PowerPC platform drivers
diff --git a/drivers/cpufreq/omap-cpufreq.c b/drivers/cpufreq/omap-cpufreq.c
new file mode 100644
index 000000000000..a6b2be7ea5a9
--- /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);