[PATCH 2/3] cpufreq: exynos: Adding cpufreq driver for exynos5440

Amit Daniel Kachhap
2013-02-06T19:39:21Z

This patch adds dvfs support for exynos5440 SOC. The nature of exynos5440
clock controller is different from previous exynos controllers so not using
the common exynos cpufreq framework. Also, the device tree parsing is added
to get different parameters like frequency, voltage etc.

Signed-off-by: Amit Daniel Kachhap <amit.daniel@samsung.com>
---
.../bindings/cpufreq/cpufreq-exynos5440.txt | 24 ++
drivers/cpufreq/Kconfig.arm | 8 +
drivers/cpufreq/Makefile | 1 +
drivers/cpufreq/exynos5440-cpufreq.c | 448 ++++++++++++++++++++
4 files changed, 481 insertions(+)
create mode 100644 Documentation/devicetree/bindings/cpufreq/cpufreq-exynos5440.txt
create mode 100644 drivers/cpufreq/exynos5440-cpufreq.c

diff --git a/Documentation/devicetree/bindings/cpufreq/cpufreq-exynos5440.txt b/Documentation/devicetree/bindings/cpufreq/cpufreq-exynos5440.txt
new file mode 100644
index 0000000..96cb0ed
--- /dev/null
+++ b/Documentation/devicetree/bindings/cpufreq/cpufreq-exynos5440.txt
@@ -0,0 +1,24 @@
+
+Exynos5440 cpufreq driver
+-------------------
+
+Exynos5440 SoC cpufreq driver for CPU frequency scaling.
+
+Required properties:
+- interrupts: Interrupt to know the completion of cpu frequency change.
+- cpufreq_tbl: Table of frequencies and voltage CPU could be transitioned into,
+ in the decreasing order. Frequency should be in KHZ units and voltage
+ should be in microvolts.
+
+All the required listed above must be defined under node cpufreq.
+
+Example:
+--------
+ cpufreq@160000 {
+ compatible = "samsung,exynos5440-cpufreq";
+ reg = <0x160000 0x1000>;
+ interrupts = <0 57 0>;
+ cpufreq_tbl = < 1200000 1025000
+ 1000000 975000
+ 800000 925000 >;
+ };
diff --git a/drivers/cpufreq/Kconfig.arm b/drivers/cpufreq/Kconfig.arm
index a0b3661..554756f 100644
--- a/drivers/cpufreq/Kconfig.arm
+++ b/drivers/cpufreq/Kconfig.arm
@@ -77,6 +77,14 @@ config ARM_EXYNOS5250_CPUFREQ
This adds the CPUFreq driver for Samsung EXYNOS5250
SoC.

+config ARM_EXYNOS5440_CPUFREQ
+ def_bool SOC_EXYNOS5440
+ help
+ This adds the CPUFreq driver for Samsung EXYNOS5440
+ SoC. The nature of exynos5440 clock controller is
+ different than previous exynos controllers so not using
+ the common exynos framework.
+
config ARM_SPEAR_CPUFREQ
bool "SPEAr CPUFreq support"
depends on PLAT_SPEAR
diff --git a/drivers/cpufreq/Makefile b/drivers/cpufreq/Makefile
index fadc4d4..5159ba4 100644
--- a/drivers/cpufreq/Makefile
+++ b/drivers/cpufreq/Makefile
@@ -50,6 +50,7 @@ obj-$(CONFIG_ARM_EXYNOS_CPUFREQ) += exynos-cpufreq.o
obj-$(CONFIG_ARM_EXYNOS4210_CPUFREQ) += exynos4210-cpufreq.o
obj-$(CONFIG_ARM_EXYNOS4X12_CPUFREQ) += exynos4x12-cpufreq.o
obj-$(CONFIG_ARM_EXYNOS5250_CPUFREQ) += exynos5250-cpufreq.o
+obj-$(CONFIG_ARM_EXYNOS5440_CPUFREQ) += exynos5440-cpufreq.o
obj-$(CONFIG_ARM_OMAP2PLUS_CPUFREQ) += omap-cpufreq.o
obj-$(CONFIG_ARM_SPEAR_CPUFREQ) += spear-cpufreq.o

diff --git a/drivers/cpufreq/exynos5440-cpufreq.c b/drivers/cpufreq/exynos5440-cpufreq.c
new file mode 100644
index 0000000..41d39e2
--- /dev/null
+++ b/drivers/cpufreq/exynos5440-cpufreq.c
@@ -0,0 +1,448 @@
+/*
+ * Copyright (c) 2013 Samsung Electronics Co., Ltd.
+ * http://www.samsung.com
+ *
+ * Amit Daniel Kachhap <amit.daniel@samsung.com>
+ *
+ * EXYNOS5440 - CPU frequency scaling support
+ *
+ * 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/clk.h>
+#include <linux/cpufreq.h>
+#include <linux/err.h>
+#include <linux/interrupt.h>
+#include <linux/io.h>
+#include <linux/of_address.h>
+#include <linux/of_irq.h>
+#include <linux/slab.h>
+
+/*Register definations*/
+#define XMU_DVFS_CTRL 0x0060
+#define XMU_PMU_P0_7 0x0064
+#define XMU_C0_3_PSTATE 0x0090
+#define XMU_P_LIMIT 0x00A0
+#define XMU_P_STATUS 0x00A4
+#define XMU_PMUEVTEN 0x00D0
+#define XMU_PMUIRQEN 0x00D4
+#define XMU_PMUIRQ 0x00D8
+
+/*PMU mask and shift definations*/
+#define P_VALUE_MASK 0x7
+
+#define XMU_DVFS_CTRL_EN_SHIFT 0
+
+#define P0_7_CPUCLKDEV_SHIFT 21
+#define P0_7_CPUCLKDEV_MASK 0x7
+#define P0_7_ATBCLKDEV_SHIFT 18
+#define P0_7_ATBCLKDEV_MASK 0x7
+#define P0_7_CSCLKDEV_SHIFT 15
+#define P0_7_CSCLKDEV_MASK 0x7
+#define P0_7_CPUEMA_SHIFT 28
+#define P0_7_CPUEMA_MASK 0xf
+#define P0_7_L2EMA_SHIFT 24
+#define P0_7_L2EMA_MASK 0xf
+#define P0_7_VDD_SHIFT 8
+#define P0_7_VDD_MASK 0x7f
+#define P0_7_FREQ_SHIFT 0
+#define P0_7_FREQ_MASK 0xff
+
+#define C0_3_PSTATE_VALID_SHIFT 8
+#define C0_3_PSTATE_CURR_SHIFT 4
+#define C0_3_PSTATE_NEW_SHIFT 0
+
+#define PSTATE_CHANGED_EVTEN_SHIFT 0
+
+#define PSTATE_CHANGED_IRQEN_SHIFT 0
+
+#define PSTATE_CHANGED_SHIFT 0
+
+/*some constant values for clock divider calculation*/
+#define CPU_DIV_FREQ_MAX 500
+#define CPU_DBG_FREQ_MAX 375
+#define CPU_ATB_FREQ_MAX 500
+
+#define PMIC_LOW_VOLT 0x30
+#define PMIC_HIGH_VOLT 0x28
+
+#define CPUEMA_HIGH 0x2
+#define CPUEMA_MID 0x4
+#define CPUEMA_LOW 0x7
+
+#define L2EMA_HIGH 0x1
+#define L2EMA_MID 0x3
+#define L2EMA_LOW 0x4
+
+#define DIV_TAB_MAX 2
+/*frequency unit is 20MHZ*/
+#define FREQ_UNIT 20
+#define MAX_VOLTAGE 1550000 /*In micro volt*/
+#define VOLTAGE_STEP 12500 /*In micro volt*/
+
+#define DRIVER_NAME "exynos5440_dvfs"
+#define DEF_TRANS_LATENCY 100000
+
+enum cpufreq_level_index {
+ L0, L1, L2, L3, L4,
+ L5, L6, L7, L8, L9,
+};
+#define CPUFREQ_LEVEL_END (L7 + 1)
+
+struct exynos_dvfs_data {
+ void __iomem *base;
+ struct resource *mem;
+ int irq;
+ struct clk *cpu_clk;
+ unsigned int cur_frequency;
+ bool dvfs_init;
+ struct cpufreq_frequency_table *freq_table;
+ struct work_struct irq_work;
+};
+
+static struct exynos_dvfs_data *dvfs_info;
+static DEFINE_MUTEX(cpufreq_lock);
+static struct cpufreq_freqs freqs;
+static struct cpufreq_frequency_table exynos_freq_table[CPUFREQ_LEVEL_END + 1];
+static unsigned int exynos_volt_table[CPUFREQ_LEVEL_END + 1];
+
+static void init_div_table(void)
+{
+ struct cpufreq_frequency_table *freq_tbl = exynos_freq_table;
+ unsigned int *volt_tbl = exynos_volt_table;
+ unsigned int tmp, clk_div, ema_div, freq, volt_id;
+ int i = 0;
+
+ for (i = 0; freq_tbl[i].frequency != CPUFREQ_TABLE_END; i++) {
+
+ freq = freq_tbl[i].frequency / 1000; /*In MHZ*/
+ clk_div = ((freq / CPU_DIV_FREQ_MAX) & P0_7_CPUCLKDEV_MASK)
+ << P0_7_CPUCLKDEV_SHIFT;
+ clk_div |= ((freq / CPU_ATB_FREQ_MAX) & P0_7_ATBCLKDEV_MASK)
+ << P0_7_ATBCLKDEV_SHIFT;
+ clk_div |= ((freq / CPU_DBG_FREQ_MAX) & P0_7_CSCLKDEV_MASK)
+ << P0_7_CSCLKDEV_SHIFT;
+
+ /*Calculate EMA*/
+ volt_id = (MAX_VOLTAGE - volt_tbl[i]) / VOLTAGE_STEP;
+ if (volt_id < PMIC_HIGH_VOLT) {
+ ema_div = (CPUEMA_HIGH << P0_7_CPUEMA_SHIFT) |
+ (L2EMA_HIGH << P0_7_L2EMA_SHIFT);
+ } else if (volt_id > PMIC_LOW_VOLT) {
+ ema_div = (CPUEMA_LOW << P0_7_CPUEMA_SHIFT) |
+ (L2EMA_LOW << P0_7_L2EMA_SHIFT);
+ } else {
+ ema_div = (CPUEMA_MID << P0_7_CPUEMA_SHIFT) |
+ (L2EMA_MID << P0_7_L2EMA_SHIFT);
+ }
+
+ tmp = (clk_div | ema_div | (volt_id << P0_7_VDD_SHIFT)
+ | ((freq / FREQ_UNIT) << P0_7_FREQ_SHIFT));
+
+ __raw_writel(tmp, dvfs_info->base + XMU_PMU_P0_7 + 4 * i);
+ }
+}
+
+void exynos_enable_dvfs(void)
+{
+ unsigned int tmp, i, cpu;
+ struct cpufreq_frequency_table *freq_table = dvfs_info->freq_table;
+ /*Disable DVFS*/
+ __raw_writel(0, dvfs_info->base + XMU_DVFS_CTRL);
+
+ /*Enable PSTATE Change Event*/
+ tmp = __raw_readl(dvfs_info->base + XMU_PMUEVTEN);
+ tmp |= (1 << PSTATE_CHANGED_EVTEN_SHIFT);
+ __raw_writel(tmp, dvfs_info->base + XMU_PMUEVTEN);
+
+ /*Enable PSTATE Change IRQ*/
+ tmp = __raw_readl(dvfs_info->base + XMU_PMUIRQEN);
+ tmp |= (1 << PSTATE_CHANGED_IRQEN_SHIFT);
+ __raw_writel(tmp, dvfs_info->base + XMU_PMUIRQEN);
+
+ /*Set initial perfromance index*/
+ for (i = 0; freq_table[i].frequency != CPUFREQ_TABLE_END; i++)
+ if (freq_table[i].frequency == dvfs_info->cur_frequency)
+ break;
+
+ if (freq_table[i].frequency == CPUFREQ_TABLE_END) {
+ pr_crit("Boot up frequency not supported\n");
+ if (i) {
+ /*Assign the highest frequency*/
+ i = 0;
+ dvfs_info->cur_frequency = freq_table[i].frequency;
+ } else {
+ return;
+ }
+ }
+ pr_info("Setting dvfs initial frequency = %u",
+ dvfs_info->cur_frequency);
+
+ for (cpu = 0; cpu < CONFIG_NR_CPUS; cpu++) {
+ tmp = __raw_readl(dvfs_info->base + XMU_C0_3_PSTATE + cpu * 4);
+ tmp &= ~(P_VALUE_MASK << C0_3_PSTATE_NEW_SHIFT);
+ tmp |= (i << C0_3_PSTATE_NEW_SHIFT);
+ __raw_writel(tmp, dvfs_info->base + XMU_C0_3_PSTATE + cpu * 4);
+ }
+
+ /*Enable DVFS*/
+ __raw_writel(1 << XMU_DVFS_CTRL_EN_SHIFT,
+ dvfs_info->base + XMU_DVFS_CTRL);
+}
+
+static int exynos_verify_speed(struct cpufreq_policy *policy)
+{
+ return cpufreq_frequency_table_verify(policy,
+ dvfs_info->freq_table);
+}
+
+static unsigned int exynos_getspeed(unsigned int cpu)
+{
+ return dvfs_info->cur_frequency;
+}
+
+static int exynos_target(struct cpufreq_policy *policy,
+ unsigned int target_freq,
+ unsigned int relation)
+{
+ unsigned int index, old_index, tmp;
+ int ret = 0, i;
+ struct cpufreq_frequency_table *freq_table = dvfs_info->freq_table;
+
+ mutex_lock(&cpufreq_lock);
+
+ freqs.old = dvfs_info->cur_frequency;
+
+ if (dvfs_info->dvfs_init == false) {
+ ret = -EAGAIN;
+ goto out;
+ }
+
+ /*
+ * The policy max have been changed so that we cannot get proper
+ * old_index with cpufreq_frequency_table_target(). Thus, ignore
+ * policy and get the index from the raw freqeuncy table.
+ */
+ for (old_index = 0;
+ freq_table[old_index].frequency != CPUFREQ_TABLE_END;
+ old_index++)
+ if (freq_table[old_index].frequency == freqs.old)
+ break;
+
+ if (freq_table[old_index].frequency == CPUFREQ_TABLE_END) {
+ ret = -EINVAL;
+ goto out;
+ }
+
+ if (cpufreq_frequency_table_target(policy, freq_table,
+ target_freq, relation, &index)) {
+ ret = -EINVAL;
+ goto out;
+ }
+
+ freqs.new = freq_table[index].frequency;
+ freqs.cpu = policy->cpu;
+
+ for_each_cpu(freqs.cpu, policy->cpus)
+ cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE);
+
+ /*Set the target frequency in all C0_3_PSTATE register*/
+ for_each_cpu(i, policy->cpus) {
+ tmp = __raw_readl(dvfs_info->base + XMU_C0_3_PSTATE + i * 4);
+ tmp &= ~(P_VALUE_MASK << C0_3_PSTATE_NEW_SHIFT);
+ tmp |= (index << C0_3_PSTATE_NEW_SHIFT);
+
+ __raw_writel(tmp, dvfs_info->base + XMU_C0_3_PSTATE + i * 4);
+ }
+out:
+ mutex_unlock(&cpufreq_lock);
+ return ret;
+}
+
+static void exynos_cpufreq_work(struct work_struct *work)
+{
+ unsigned int cur_pstate, index;
+ struct cpufreq_policy *policy = cpufreq_cpu_get(0); /* boot CPU */
+ struct cpufreq_frequency_table *freq_table = dvfs_info->freq_table;
+
+ mutex_lock(&cpufreq_lock);
+
+ freqs.old = dvfs_info->cur_frequency;
+
+ cur_pstate = __raw_readl(dvfs_info->base + XMU_P_STATUS);
+ if (cur_pstate >> C0_3_PSTATE_VALID_SHIFT & 0x1)
+ index = (cur_pstate >> C0_3_PSTATE_CURR_SHIFT) & P_VALUE_MASK;
+ else
+ index = (cur_pstate >> C0_3_PSTATE_NEW_SHIFT) & P_VALUE_MASK;
+
+ if (index < CPUFREQ_LEVEL_END)
+ freqs.new = freq_table[index].frequency;
+
+ for_each_cpu(freqs.cpu, policy->cpus)
+ cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE);
+
+ dvfs_info->cur_frequency = freqs.new;
+
+ cpufreq_cpu_put(policy);
+ mutex_unlock(&cpufreq_lock);
+ enable_irq(dvfs_info->irq);
+}
+
+static irqreturn_t exynos_cpufreq_irq(int irq, void *id)
+{
+ unsigned int tmp;
+
+ tmp = __raw_readl(dvfs_info->base + XMU_PMUIRQ);
+ if (tmp >> PSTATE_CHANGED_SHIFT & 0x1) {
+ __raw_writel(tmp, dvfs_info->base + XMU_PMUIRQ);
+
+ if (dvfs_info->dvfs_init == true) {
+ disable_irq_nosync(irq);
+ schedule_work(&dvfs_info->irq_work);
+ }
+ }
+ return IRQ_HANDLED;
+}
+
+static int exynos_cpufreq_cpu_init(struct cpufreq_policy *policy)
+{
+ policy->cur = policy->min = policy->max = dvfs_info->cur_frequency;
+
+ cpufreq_frequency_table_get_attr(dvfs_info->freq_table, policy->cpu);
+
+ /* set the transition latency value */
+ policy->cpuinfo.transition_latency = DEF_TRANS_LATENCY;
+
+ /*
+ * EXYNOS5440 multi-core processors has 4 cores
+ * that the frequency cannot be set independently.
+ * Each cpu is bound to the same speed.
+ * So the affected cpu is all of the cpus.
+ */
+ if (num_online_cpus() == 1) {
+ cpumask_copy(policy->related_cpus, cpu_possible_mask);
+ cpumask_copy(policy->cpus, cpu_online_mask);
+ } else {
+ policy->shared_type = CPUFREQ_SHARED_TYPE_ANY;
+ cpumask_setall(policy->cpus);
+ }
+
+ return cpufreq_frequency_table_cpuinfo(policy, dvfs_info->freq_table);
+}
+
+static struct cpufreq_driver exynos_driver = {
+ .flags = CPUFREQ_STICKY,
+ .verify = exynos_verify_speed,
+ .target = exynos_target,
+ .get = exynos_getspeed,
+ .init = exynos_cpufreq_cpu_init,
+ .name = DRIVER_NAME,
+};
+
+static int __init exynos_cpufreq_init(void)
+{
+ int ret = -EINVAL, len, i;
+ struct device_node *np;
+ struct cpufreq_frequency_table *freq_tbl = exynos_freq_table;
+ unsigned int *volt_tbl = exynos_volt_table;
+ const struct property *prop;
+ const __be32 *val;
+
+ np = of_find_compatible_node(NULL, NULL, "samsung,exynos5440-cpufreq");
+ if (!np)
+ return -ENODEV;
+
+ dvfs_info = kzalloc(sizeof(struct exynos_dvfs_data), GFP_KERNEL);
+ if (!dvfs_info) {
+ of_node_put(np);
+ return -ENOMEM;
+ }
+
+ dvfs_info->base = of_iomap(np, 0);
+ if (!dvfs_info->base) {
+ pr_err("No cpufreq memory map found\n");
+ ret = -ENODEV;
+ goto err_map;
+
+ }
+
+ dvfs_info->irq = irq_of_parse_and_map(np, 0);
+
+ if (dvfs_info->irq == 0) {
+ pr_err("No cpufreq irq found\n");
+ ret = -ENODEV;
+ goto err_irq_parse;
+ }
+
+ prop = of_find_property(np, "cpufreq_tbl", NULL);
+ if (!prop || !prop->value) {
+ pr_err("No cpufreq table found\n");
+ ret = -ENODEV;
+ goto err_irq_parse;
+ }
+
+ len = prop->length / sizeof(u32);
+ val = prop->value;
+
+ if ((len == 0) || (len / 2 > CPUFREQ_LEVEL_END)) {
+ pr_err("Invalid cpufreq table\n");
+ ret = -ENODEV;
+ goto err_irq_parse;
+ }
+
+ for (i = 0; i < (len / 2); i++) {
+ freq_tbl[i].index = i;
+ freq_tbl[i].frequency = be32_to_cpup(val++);
+ volt_tbl[i] = be32_to_cpup(val++);
+ }
+
+ freq_tbl[i].index = i;
+ freq_tbl[i].frequency = CPUFREQ_TABLE_END;
+
+ dvfs_info->freq_table = freq_tbl;
+
+ dvfs_info->cpu_clk = clk_get(NULL, "armclk");
+ if (IS_ERR(dvfs_info->cpu_clk)) {
+ pr_err("Failed to get cpu clock\n");
+ ret = PTR_ERR(dvfs_info->cpu_clk);
+ goto err_irq_parse;
+ }
+
+ INIT_WORK(&dvfs_info->irq_work, exynos_cpufreq_work);
+ if (request_irq(dvfs_info->irq, exynos_cpufreq_irq,
+ IRQF_TRIGGER_NONE, DRIVER_NAME, dvfs_info)) {
+ pr_err("Failed to register IRQ\n");
+ ret = -ENODEV;
+ goto err_irq_req;
+ }
+
+ dvfs_info->cur_frequency = clk_get_rate(dvfs_info->cpu_clk) / 1000;
+ init_div_table();
+ exynos_enable_dvfs();
+
+ if (cpufreq_register_driver(&exynos_driver)) {
+ pr_err("%s: failed to register cpufreq driver\n", __func__);
+ goto err_register;
+ }
+
+ of_node_put(np);
+ dvfs_info->dvfs_init = true;
+ pr_info("exynos5440 DVFS initialised.\n");
+
+ return 0;
+
+err_register:
+ free_irq(dvfs_info->irq, dvfs_info);
+err_irq_req:
+ clk_put(dvfs_info->cpu_clk);
+err_irq_parse:
+ iounmap(dvfs_info->base);
+err_map:
+ of_node_put(np);
+ kfree(dvfs_info);
+ pr_err("%s: failed initialization\n", __func__);
+ return -EINVAL;
+}
+late_initcall(exynos_cpufreq_init);
--
1.7.10.4