[ARM] pxa: add preliminary CPUFREQ support for PXA3xx

Signed-off-by: Eric Miao <eric.miao@marvell.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

2 files changed, 259 insertions, 0 deletions

diff --git a/arch/arm/mach-pxa/Makefile b/arch/arm/mach-pxa/Makefile
index 7ab8a2e..d31c997 100644
--- a/arch/arm/mach-pxa/Makefile
+++ b/arch/arm/mach-pxa/Makefile
@@ -10,6 +10,7 @@ obj-$(CONFIG_PM)		+= pm.o sleep.o standby.o
 ifeq ($(CONFIG_CPU_FREQ),y)
 obj-$(CONFIG_PXA25x)		+= cpufreq-pxa2xx.o
 obj-$(CONFIG_PXA27x)		+= cpufreq-pxa2xx.o
+obj-$(CONFIG_PXA3xx)		+= cpufreq-pxa3xx.o
 endif
 
 # Generic drivers that other drivers may depend upon
diff --git a/arch/arm/mach-pxa/cpufreq-pxa3xx.c b/arch/arm/mach-pxa/cpufreq-pxa3xx.c
new file mode 100644
index 0000000..1ea0c9c
--- /dev/null
+++ b/arch/arm/mach-pxa/cpufreq-pxa3xx.c
@@ -0,0 +1,258 @@
+/*
+ * linux/arch/arm/mach-pxa/cpufreq-pxa3xx.c
+ *
+ * Copyright (C) 2008 Marvell International Ltd.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ */
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/sched.h>
+#include <linux/init.h>
+#include <linux/cpufreq.h>
+
+#include <mach/hardware.h>
+#include <mach/pxa-regs.h>
+#include <mach/pxa3xx-regs.h>
+
+#include "generic.h"
+
+#define HSS_104M	(0)
+#define HSS_156M	(1)
+#define HSS_208M	(2)
+#define HSS_312M	(3)
+
+#define SMCFS_78M	(0)
+#define SMCFS_104M	(2)
+#define SMCFS_208M	(5)
+
+#define SFLFS_104M	(0)
+#define SFLFS_156M	(1)
+#define SFLFS_208M	(2)
+#define SFLFS_312M	(3)
+
+#define XSPCLK_156M	(0)
+#define XSPCLK_NONE	(3)
+
+#define DMCFS_26M	(0)
+#define DMCFS_260M	(3)
+
+struct pxa3xx_freq_info {
+	unsigned int cpufreq_mhz;
+	unsigned int core_xl : 5;
+	unsigned int core_xn : 3;
+	unsigned int hss : 2;
+	unsigned int dmcfs : 2;
+	unsigned int smcfs : 3;
+	unsigned int sflfs : 2;
+	unsigned int df_clkdiv : 3;
+
+	int	vcc_core;	/* in mV */
+	int	vcc_sram;	/* in mV */
+};
+
+#define OP(cpufreq, _xl, _xn, _hss, _dmc, _smc, _sfl, _dfi, vcore, vsram) \
+{									\
+	.cpufreq_mhz	= cpufreq,					\
+	.core_xl	= _xl,						\
+	.core_xn	= _xn,						\
+	.hss		= HSS_##_hss##M,				\
+	.dmcfs		= DMCFS_##_dmc##M,				\
+	.smcfs		= SMCFS_##_smc##M,				\
+	.sflfs		= SFLFS_##_sfl##M,				\
+	.df_clkdiv	= _dfi,						\
+	.vcc_core	= vcore,					\
+	.vcc_sram	= vsram,					\
+}
+
+static struct pxa3xx_freq_info pxa300_freqs[] = {
+	/*  CPU XL XN  HSS DMEM SMEM SRAM DFI VCC_CORE VCC_SRAM */
+	OP(104,  8, 1, 104, 260,  78, 104, 3, 1000, 1100), /* 104MHz */
+	OP(208, 16, 1, 104, 260, 104, 156, 2, 1000, 1100), /* 208MHz */
+	OP(416, 16, 2, 156, 260, 104, 208, 2, 1100, 1200), /* 416MHz */
+	OP(624, 24, 2, 208, 260, 208, 312, 3, 1375, 1400), /* 624MHz */
+};
+
+static struct pxa3xx_freq_info pxa320_freqs[] = {
+	/*  CPU XL XN  HSS DMEM SMEM SRAM DFI VCC_CORE VCC_SRAM */
+	OP(104,  8, 1, 104, 260,  78, 104, 3, 1000, 1100), /* 104MHz */
+	OP(208, 16, 1, 104, 260, 104, 156, 2, 1000, 1100), /* 208MHz */
+	OP(416, 16, 2, 156, 260, 104, 208, 2, 1100, 1200), /* 416MHz */
+	OP(624, 24, 2, 208, 260, 208, 312, 3, 1375, 1400), /* 624MHz */
+	OP(806, 31, 2, 208, 260, 208, 312, 3, 1400, 1400), /* 806MHz */
+};
+
+static unsigned int pxa3xx_freqs_num;
+static struct pxa3xx_freq_info *pxa3xx_freqs;
+static struct cpufreq_frequency_table *pxa3xx_freqs_table;
+
+static int setup_freqs_table(struct cpufreq_policy *policy,
+			     struct pxa3xx_freq_info *freqs, int num)
+{
+	struct cpufreq_frequency_table *table;
+	int i;
+
+	table = kzalloc((num + 1) * sizeof(*table), GFP_KERNEL);
+	if (table == NULL)
+		return -ENOMEM;
+
+	for (i = 0; i < num; i++) {
+		table[i].index = i;
+		table[i].frequency = freqs[i].cpufreq_mhz * 1000;
+	}
+	table[num].frequency = i;
+	table[num].frequency = CPUFREQ_TABLE_END;
+
+	pxa3xx_freqs = freqs;
+	pxa3xx_freqs_num = num;
+	pxa3xx_freqs_table = table;
+
+	return cpufreq_frequency_table_cpuinfo(policy, table);
+}
+
+static void __update_core_freq(struct pxa3xx_freq_info *info)
+{
+	uint32_t mask = ACCR_XN_MASK | ACCR_XL_MASK;
+	uint32_t accr = ACCR;
+	uint32_t xclkcfg;
+
+	accr &= ~(ACCR_XN_MASK | ACCR_XL_MASK | ACCR_XSPCLK_MASK);
+	accr |= ACCR_XN(info->core_xn) | ACCR_XL(info->core_xl);
+
+	/* No clock until core PLL is re-locked */
+	accr |= ACCR_XSPCLK(XSPCLK_NONE);
+
+	xclkcfg = (info->core_xn == 2) ? 0x3 : 0x2;	/* turbo bit */
+
+	ACCR = accr;
+	__asm__("mcr p14, 0, %0, c6, c0, 0\n" : : "r"(xclkcfg));
+
+	while ((ACSR & mask) != (accr & mask))
+		cpu_relax();
+}
+
+static void __update_bus_freq(struct pxa3xx_freq_info *info)
+{
+	uint32_t mask;
+	uint32_t accr = ACCR;
+
+	mask = ACCR_SMCFS_MASK | ACCR_SFLFS_MASK | ACCR_HSS_MASK |
+		ACCR_DMCFS_MASK;
+
+	accr &= ~mask;
+	accr |= ACCR_SMCFS(info->smcfs) | ACCR_SFLFS(info->sflfs) |
+		ACCR_HSS(info->hss) | ACCR_DMCFS(info->dmcfs);
+
+	ACCR = accr;
+
+	while ((ACSR & mask) != (accr & mask))
+		cpu_relax();
+}
+
+static int pxa3xx_cpufreq_verify(struct cpufreq_policy *policy)
+{
+	return cpufreq_frequency_table_verify(policy, pxa3xx_freqs_table);
+}
+
+static unsigned int pxa3xx_cpufreq_get(unsigned int cpu)
+{
+	return get_clk_frequency_khz(0);
+}
+
+static int pxa3xx_cpufreq_set(struct cpufreq_policy *policy,
+			      unsigned int target_freq,
+			      unsigned int relation)
+{
+	struct pxa3xx_freq_info *next;
+	struct cpufreq_freqs freqs;
+	unsigned long flags;
+	int idx;
+
+	if (policy->cpu != 0)
+		return -EINVAL;
+
+	/* Lookup the next frequency */
+	if (cpufreq_frequency_table_target(policy, pxa3xx_freqs_table,
+				target_freq, relation, &idx))
+		return -EINVAL;
+
+	next = &pxa3xx_freqs[idx];
+
+	freqs.old = policy->cur;
+	freqs.new = next->cpufreq_mhz * 1000;
+	freqs.cpu = policy->cpu;
+
+	pr_debug("CPU frequency from %d MHz to %d MHz%s\n",
+			freqs.old / 1000, freqs.new / 1000,
+			(freqs.old == freqs.new) ? " (skipped)" : "");
+
+	if (freqs.old == target_freq)
+		return 0;
+
+	cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE);
+
+	local_irq_save(flags);
+	__update_core_freq(next);
+	__update_bus_freq(next);
+	local_irq_restore(flags);
+
+	cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE);
+
+	return 0;
+}
+
+static __init int pxa3xx_cpufreq_init(struct cpufreq_policy *policy)
+{
+	int ret = -EINVAL;
+
+	/* set default policy and cpuinfo */
+	policy->governor = CPUFREQ_DEFAULT_GOVERNOR;
+	policy->cpuinfo.min_freq = 104000;
+	policy->cpuinfo.max_freq = (cpu_is_pxa320()) ? 806000 : 624000;
+	policy->cpuinfo.transition_latency = 1000; /* FIXME: 1 ms, assumed */
+	policy->cur = policy->min = policy->max = get_clk_frequency_khz(0);
+
+	if (cpu_is_pxa300() || cpu_is_pxa310())
+		ret = setup_freqs_table(policy, ARRAY_AND_SIZE(pxa300_freqs));
+
+	if (cpu_is_pxa320())
+		ret = setup_freqs_table(policy, ARRAY_AND_SIZE(pxa320_freqs));
+
+	if (ret) {
+		pr_err("failed to setup frequency table\n");
+		return ret;
+	}
+
+	pr_info("CPUFREQ support for PXA3xx initialized\n");
+	return 0;
+}
+
+static struct cpufreq_driver pxa3xx_cpufreq_driver = {
+	.verify		= pxa3xx_cpufreq_verify,
+	.target		= pxa3xx_cpufreq_set,
+	.init		= pxa3xx_cpufreq_init,
+	.get		= pxa3xx_cpufreq_get,
+	.name		= "pxa3xx-cpufreq",
+};
+
+static int __init cpufreq_init(void)
+{
+	if (cpu_is_pxa3xx())
+		return cpufreq_register_driver(&pxa3xx_cpufreq_driver);
+
+	return 0;
+}
+module_init(cpufreq_init);
+
+static void __exit cpufreq_exit(void)
+{
+	cpufreq_unregister_driver(&pxa3xx_cpufreq_driver);
+}
+module_exit(cpufreq_exit);
+
+MODULE_DESCRIPTION("CPU frequency scaling driver for PXA3xx");
+MODULE_LICENSE("GPL");