ARM: S5PV210: Add support CPUFREQ

This patch adds CPUFREQ driver for supporting DFS(Dynamic Frequency Scaling).
Signed-off-by: Jaecheol Lee <jc.lee@samsung.com>
Signed-off-by: Sangbeom Kim <sbkim73@samsung.com>
Signed-off-by: Kukjin Kim <kgene.kim@samsung.com>

arch/arm/mach-s5pv210/cpufreq.c

+/* linux/arch/arm/mach-s5pv210/cpufreq.c
+ *
+ * Copyright (c) 2010 Samsung Electronics Co., Ltd.
+ *		http://www.samsung.com
+ *
+ * CPU frequency scaling for S5PC110/S5PV210
+ *
+ * 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/init.h>
+#include <linux/err.h>
+#include <linux/clk.h>
+#include <linux/io.h>
+#include <linux/cpufreq.h>
+
+#include <mach/map.h>
+#include <mach/regs-clock.h>
+
+static struct clk *cpu_clk;
+static struct clk *dmc0_clk;
+static struct clk *dmc1_clk;
+static struct cpufreq_freqs freqs;
+
+/* APLL M,P,S values for 1G/800Mhz */
+#define APLL_VAL_1000	((1 << 31) | (125 << 16) | (3 << 8) | 1)
+#define APLL_VAL_800	((1 << 31) | (100 << 16) | (3 << 8) | 1)
+
+/*
+ * DRAM configurations to calculate refresh counter for changing
+ * frequency of memory.
+ */
+struct dram_conf {
+	unsigned long freq;	/* HZ */
+	unsigned long refresh;	/* DRAM refresh counter * 1000 */
+};
+
+/* DRAM configuration (DMC0 and DMC1) */
+static struct dram_conf s5pv210_dram_conf[2];
+
+enum perf_level {
+	L0, L1, L2, L3, L4,
+};
+
+enum s5pv210_mem_type {
+	LPDDR	= 0x1,
+	LPDDR2	= 0x2,
+	DDR2	= 0x4,
+};
+
+enum s5pv210_dmc_port {
+	DMC0 = 0,
+	DMC1,
+};
+
+static struct cpufreq_frequency_table s5pv210_freq_table[] = {
+	{L0, 1000*1000},
+	{L1, 800*1000},
+	{L2, 400*1000},
+	{L3, 200*1000},
+	{L4, 100*1000},
+	{0, CPUFREQ_TABLE_END},
+};
+
+static u32 clkdiv_val[5][11] = {
+	/*
+	 * Clock divider value for following
+	 * { APLL, A2M, HCLK_MSYS, PCLK_MSYS,
+	 *   HCLK_DSYS, PCLK_DSYS, HCLK_PSYS, PCLK_PSYS,
+	 *   ONEDRAM, MFC, G3D }
+	 */
+
+	/* L0 : [1000/200/100][166/83][133/66][200/200] */
+	{0, 4, 4, 1, 3, 1, 4, 1, 3, 0, 0},
+
+	/* L1 : [800/200/100][166/83][133/66][200/200] */
+	{0, 3, 3, 1, 3, 1, 4, 1, 3, 0, 0},
+
+	/* L2 : [400/200/100][166/83][133/66][200/200] */
+	{1, 3, 1, 1, 3, 1, 4, 1, 3, 0, 0},
+
+	/* L3 : [200/200/100][166/83][133/66][200/200] */
+	{3, 3, 1, 1, 3, 1, 4, 1, 3, 0, 0},
+
+	/* L4 : [100/100/100][83/83][66/66][100/100] */
+	{7, 7, 0, 0, 7, 0, 9, 0, 7, 0, 0},
+};
+
+/*
+ * This function set DRAM refresh counter
+ * accoriding to operating frequency of DRAM
+ * ch: DMC port number 0 or 1
+ * freq: Operating frequency of DRAM(KHz)
+ */
+static void s5pv210_set_refresh(enum s5pv210_dmc_port ch, unsigned long freq)
+{
+	unsigned long tmp, tmp1;
+	void __iomem *reg = NULL;
+
+	if (ch == DMC0)
+		reg = (S5P_VA_DMC0 + 0x30);
+	else if (ch == DMC1)
+		reg = (S5P_VA_DMC1 + 0x30);
+	else
+		printk(KERN_ERR "Cannot find DMC port\n");
+
+	/* Find current DRAM frequency */
+	tmp = s5pv210_dram_conf[ch].freq;
+
+	do_div(tmp, freq);
+
+	tmp1 = s5pv210_dram_conf[ch].refresh;
+
+	do_div(tmp1, tmp);
+
+	__raw_writel(tmp1, reg);
+}
+
+int s5pv210_verify_speed(struct cpufreq_policy *policy)
+{
+	if (policy->cpu)
+		return -EINVAL;
+
+	return cpufreq_frequency_table_verify(policy, s5pv210_freq_table);
+}
+
+unsigned int s5pv210_getspeed(unsigned int cpu)
+{
+	if (cpu)
+		return 0;
+
+	return clk_get_rate(cpu_clk) / 1000;
+}
+
+static int s5pv210_target(struct cpufreq_policy *policy,
+			  unsigned int target_freq,
+			  unsigned int relation)
+{
+	unsigned long reg;
+	unsigned int index, priv_index;
+	unsigned int pll_changing = 0;
+	unsigned int bus_speed_changing = 0;
+
+	freqs.old = s5pv210_getspeed(0);
+
+	if (cpufreq_frequency_table_target(policy, s5pv210_freq_table,
+					   target_freq, relation, &index))
+		return -EINVAL;
+
+	freqs.new = s5pv210_freq_table[index].frequency;
+	freqs.cpu = 0;
+
+	if (freqs.new == freqs.old)
+		return 0;
+
+	/* Finding current running level index */
+	if (cpufreq_frequency_table_target(policy, s5pv210_freq_table,
+					   freqs.old, relation, &priv_index))
+		return -EINVAL;
+
+	cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE);
+
+	if (freqs.new > freqs.old) {
+		/* Voltage up: will be implemented */
+	}
+
+	/* Check if there need to change PLL */
+	if ((index == L0) || (priv_index == L0))
+		pll_changing = 1;
+
+	/* Check if there need to change System bus clock */
+	if ((index == L4) || (priv_index == L4))
+		bus_speed_changing = 1;
+
+	if (bus_speed_changing) {
+		/*
+		 * Reconfigure DRAM refresh counter value for minimum
+		 * temporary clock while changing divider.
+		 * expected clock is 83Mhz : 7.8usec/(1/83Mhz) = 0x287
+		 */
+		if (pll_changing)
+			s5pv210_set_refresh(DMC1, 83000);
+		else
+			s5pv210_set_refresh(DMC1, 100000);
+
+		s5pv210_set_refresh(DMC0, 83000);
+	}
+
+	/*
+	 * APLL should be changed in this level
+	 * APLL -> MPLL(for stable transition) -> APLL
+	 * Some clock source's clock API are not prepared.
+	 * Do not use clock API in below code.
+	 */
+	if (pll_changing) {
+		/*
+		 * 1. Temporary Change divider for MFC and G3D
+		 * SCLKA2M(200/1=200)->(200/4=50)Mhz
+		 */
+		reg = __raw_readl(S5P_CLK_DIV2);
+		reg &= ~(S5P_CLKDIV2_G3D_MASK | S5P_CLKDIV2_MFC_MASK);
+		reg |= (3 << S5P_CLKDIV2_G3D_SHIFT) |
+			(3 << S5P_CLKDIV2_MFC_SHIFT);
+		__raw_writel(reg, S5P_CLK_DIV2);
+
+		/* For MFC, G3D dividing */
+		do {
+			reg = __raw_readl(S5P_CLKDIV_STAT0);
+		} while (reg & ((1 << 16) | (1 << 17)));
+
+		/*
+		 * 2. Change SCLKA2M(200Mhz)to SCLKMPLL in MFC_MUX, G3D MUX
+		 * (200/4=50)->(667/4=166)Mhz
+		 */
+		reg = __raw_readl(S5P_CLK_SRC2);
+		reg &= ~(S5P_CLKSRC2_G3D_MASK | S5P_CLKSRC2_MFC_MASK);
+		reg |= (1 << S5P_CLKSRC2_G3D_SHIFT) |
+			(1 << S5P_CLKSRC2_MFC_SHIFT);
+		__raw_writel(reg, S5P_CLK_SRC2);
+
+		do {
+			reg = __raw_readl(S5P_CLKMUX_STAT1);
+		} while (reg & ((1 << 7) | (1 << 3)));
+
+		/*
+		 * 3. DMC1 refresh count for 133Mhz if (index == L4) is
+		 * true refresh counter is already programed in upper
+		 * code. 0x287@83Mhz
+		 */
+		if (!bus_speed_changing)
+			s5pv210_set_refresh(DMC1, 133000);
+
+		/* 4. SCLKAPLL -> SCLKMPLL */
+		reg = __raw_readl(S5P_CLK_SRC0);
+		reg &= ~(S5P_CLKSRC0_MUX200_MASK);
+		reg |= (0x1 << S5P_CLKSRC0_MUX200_SHIFT);
+		__raw_writel(reg, S5P_CLK_SRC0);
+
+		do {
+			reg = __raw_readl(S5P_CLKMUX_STAT0);
+		} while (reg & (0x1 << 18));
+
+	}
+
+	/* Change divider */
+	reg = __raw_readl(S5P_CLK_DIV0);
+
+	reg &= ~(S5P_CLKDIV0_APLL_MASK | S5P_CLKDIV0_A2M_MASK |
+		S5P_CLKDIV0_HCLK200_MASK | S5P_CLKDIV0_PCLK100_MASK |
+		S5P_CLKDIV0_HCLK166_MASK | S5P_CLKDIV0_PCLK83_MASK |
+		S5P_CLKDIV0_HCLK133_MASK | S5P_CLKDIV0_PCLK66_MASK);
+
+	reg |= ((clkdiv_val[index][0] << S5P_CLKDIV0_APLL_SHIFT) |
+		(clkdiv_val[index][1] << S5P_CLKDIV0_A2M_SHIFT) |
+		(clkdiv_val[index][2] << S5P_CLKDIV0_HCLK200_SHIFT) |
+		(clkdiv_val[index][3] << S5P_CLKDIV0_PCLK100_SHIFT) |
+		(clkdiv_val[index][4] << S5P_CLKDIV0_HCLK166_SHIFT) |
+		(clkdiv_val[index][5] << S5P_CLKDIV0_PCLK83_SHIFT) |
+		(clkdiv_val[index][6] << S5P_CLKDIV0_HCLK133_SHIFT) |
+		(clkdiv_val[index][7] << S5P_CLKDIV0_PCLK66_SHIFT));
+
+	__raw_writel(reg, S5P_CLK_DIV0);
+
+	do {
+		reg = __raw_readl(S5P_CLKDIV_STAT0);
+	} while (reg & 0xff);
+
+	/* ARM MCS value changed */
+	reg = __raw_readl(S5P_ARM_MCS_CON);
+	reg &= ~0x3;
+	if (index >= L3)
+		reg |= 0x3;
+	else
+		reg |= 0x1;
+
+	__raw_writel(reg, S5P_ARM_MCS_CON);
+
+	if (pll_changing) {
+		/* 5. Set Lock time = 30us*24Mhz = 0x2cf */
+		__raw_writel(0x2cf, S5P_APLL_LOCK);
+
+		/*
+		 * 6. Turn on APLL
+		 * 6-1. Set PMS values
+		 * 6-2. Wait untile the PLL is locked
+		 */
+		if (index == L0)
+			__raw_writel(APLL_VAL_1000, S5P_APLL_CON);
+		else
+			__raw_writel(APLL_VAL_800, S5P_APLL_CON);
+
+		do {
+			reg = __raw_readl(S5P_APLL_CON);
+		} while (!(reg & (0x1 << 29)));
+
+		/*
+		 * 7. Change souce clock from SCLKMPLL(667Mhz)
+		 * to SCLKA2M(200Mhz) in MFC_MUX and G3D MUX
+		 * (667/4=166)->(200/4=50)Mhz
+		 */
+		reg = __raw_readl(S5P_CLK_SRC2);
+		reg &= ~(S5P_CLKSRC2_G3D_MASK | S5P_CLKSRC2_MFC_MASK);
+		reg |= (0 << S5P_CLKSRC2_G3D_SHIFT) |
+			(0 << S5P_CLKSRC2_MFC_SHIFT);
+		__raw_writel(reg, S5P_CLK_SRC2);
+
+		do {
+			reg = __raw_readl(S5P_CLKMUX_STAT1);
+		} while (reg & ((1 << 7) | (1 << 3)));
+
+		/*
+		 * 8. Change divider for MFC and G3D
+		 * (200/4=50)->(200/1=200)Mhz
+		 */
+		reg = __raw_readl(S5P_CLK_DIV2);
+		reg &= ~(S5P_CLKDIV2_G3D_MASK | S5P_CLKDIV2_MFC_MASK);
+		reg |= (clkdiv_val[index][10] << S5P_CLKDIV2_G3D_SHIFT) |
+			(clkdiv_val[index][9] << S5P_CLKDIV2_MFC_SHIFT);
+		__raw_writel(reg, S5P_CLK_DIV2);
+
+		/* For MFC, G3D dividing */
+		do {
+			reg = __raw_readl(S5P_CLKDIV_STAT0);
+		} while (reg & ((1 << 16) | (1 << 17)));
+
+		/* 9. Change MPLL to APLL in MSYS_MUX */
+		reg = __raw_readl(S5P_CLK_SRC0);
+		reg &= ~(S5P_CLKSRC0_MUX200_MASK);
+		reg |= (0x0 << S5P_CLKSRC0_MUX200_SHIFT);
+		__raw_writel(reg, S5P_CLK_SRC0);
+
+		do {
+			reg = __raw_readl(S5P_CLKMUX_STAT0);
+		} while (reg & (0x1 << 18));
+
+		/*
+		 * 10. DMC1 refresh counter
+		 * L4 : DMC1 = 100Mhz 7.8us/(1/100) = 0x30c
+		 * Others : DMC1 = 200Mhz 7.8us/(1/200) = 0x618
+		 */
+		if (!bus_speed_changing)
+			s5pv210_set_refresh(DMC1, 200000);
+	}
+
+	/*
+	 * L4 level need to change memory bus speed, hence onedram clock divier
+	 * and memory refresh parameter should be changed
+	 */
+	if (bus_speed_changing) {
+		reg = __raw_readl(S5P_CLK_DIV6);
+		reg &= ~S5P_CLKDIV6_ONEDRAM_MASK;
+		reg |= (clkdiv_val[index][8] << S5P_CLKDIV6_ONEDRAM_SHIFT);
+		__raw_writel(reg, S5P_CLK_DIV6);
+
+		do {
+			reg = __raw_readl(S5P_CLKDIV_STAT1);
+		} while (reg & (1 << 15));
+
+		/* Reconfigure DRAM refresh counter value */
+		if (index != L4) {
+			/*
+			 * DMC0 : 166Mhz
+			 * DMC1 : 200Mhz
+			 */
+			s5pv210_set_refresh(DMC0, 166000);
+			s5pv210_set_refresh(DMC1, 200000);
+		} else {
+			/*
+			 * DMC0 : 83Mhz
+			 * DMC1 : 100Mhz
+			 */
+			s5pv210_set_refresh(DMC0, 83000);
+			s5pv210_set_refresh(DMC1, 100000);
+		}
+	}
+
+	if (freqs.new < freqs.old) {
+		/* Voltage down: will be implemented */
+	}
+
+	cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE);
+
+	printk(KERN_DEBUG "Perf changed[L%d]\n", index);
+
+	return 0;
+}
+
+#ifdef CONFIG_PM
+static int s5pv210_cpufreq_suspend(struct cpufreq_policy *policy,
+				   pm_message_t pmsg)
+{
+	return 0;
+}
+
+static int s5pv210_cpufreq_resume(struct cpufreq_policy *policy)
+{
+	return 0;
+}
+#endif
+
+static int check_mem_type(void __iomem *dmc_reg)
+{
+	unsigned long val;
+
+	val = __raw_readl(dmc_reg + 0x4);
+	val = (val & (0xf << 8));
+
+	return val >> 8;
+}
+
+static int __init s5pv210_cpu_init(struct cpufreq_policy *policy)
+{
+	unsigned long mem_type;
+
+	cpu_clk = clk_get(NULL, "armclk");
+	if (IS_ERR(cpu_clk))
+		return PTR_ERR(cpu_clk);
+
+	dmc0_clk = clk_get(NULL, "sclk_dmc0");
+	if (IS_ERR(dmc0_clk)) {
+		clk_put(cpu_clk);
+		return PTR_ERR(dmc0_clk);
+	}
+
+	dmc1_clk = clk_get(NULL, "hclk_msys");
+	if (IS_ERR(dmc1_clk)) {
+		clk_put(dmc0_clk);
+		clk_put(cpu_clk);
+		return PTR_ERR(dmc1_clk);
+	}
+
+	if (policy->cpu != 0)
+		return -EINVAL;
+
+	/*
+	 * check_mem_type : This driver only support LPDDR & LPDDR2.
+	 * other memory type is not supported.
+	 */
+	mem_type = check_mem_type(S5P_VA_DMC0);
+
+	if ((mem_type != LPDDR) && (mem_type != LPDDR2)) {
+		printk(KERN_ERR "CPUFreq doesn't support this memory type\n");
+		return -EINVAL;
+	}
+
+	/* Find current refresh counter and frequency each DMC */
+	s5pv210_dram_conf[0].refresh = (__raw_readl(S5P_VA_DMC0 + 0x30) * 1000);
+	s5pv210_dram_conf[0].freq = clk_get_rate(dmc0_clk);
+
+	s5pv210_dram_conf[1].refresh = (__raw_readl(S5P_VA_DMC1 + 0x30) * 1000);
+	s5pv210_dram_conf[1].freq = clk_get_rate(dmc1_clk);
+
+	policy->cur = policy->min = policy->max = s5pv210_getspeed(0);
+
+	cpufreq_frequency_table_get_attr(s5pv210_freq_table, policy->cpu);
+
+	policy->cpuinfo.transition_latency = 40000;
+
+	return cpufreq_frequency_table_cpuinfo(policy, s5pv210_freq_table);
+}
+
+static struct cpufreq_driver s5pv210_driver = {
+	.flags		= CPUFREQ_STICKY,
+	.verify		= s5pv210_verify_speed,
+	.target		= s5pv210_target,
+	.get		= s5pv210_getspeed,
+	.init		= s5pv210_cpu_init,
+	.name		= "s5pv210",
+#ifdef CONFIG_PM
+	.suspend	= s5pv210_cpufreq_suspend,
+	.resume		= s5pv210_cpufreq_resume,
+#endif
+};
+
+static int __init s5pv210_cpufreq_init(void)
+{
+	return cpufreq_register_driver(&s5pv210_driver);
+}
+
+late_initcall(s5pv210_cpufreq_init);