Re: [PATCH V2 1/4] cpufreq: exynos: Adding cpufreq driver for exynos5440
From: Viresh Kumar
Date: Mon Mar 04 2013 - 20:19:05 EST
On 2 March 2013 15:04, Amit Daniel Kachhap <amit.daniel@xxxxxxxxxxx> wrote:
> This patch adds dvfs support for exynos5440 SOC. This soc has 4 cores and
> they run at same frequency. The nature of exynos5440 clock controller is
> different from previous exynos controllers so not using the common exynos
> cpufreq framework. The major difference being interrupt notfication for
> frequency change. Also, OPP library is used for device tree parsing to get
> different parameters like frequency, voltage etc. Since the opp library sorts
> the frequency table in ascending order so they are again re-arranged in
> descending order. This will have one-to-one mapping with the clock controller
> state management logic.
>
> Signed-off-by: Amit Daniel Kachhap <amit.daniel@xxxxxxxxxxx>
> ---
> Changes in V2:
> * Added OPP library support to parse DT parameters.
> * Removed a hack to handle interrupts in bootup.
> * Added many review comments from Viresh and Inder.
Added? Thanks :)
>
> All these patches are dependent on Thomas Abraham common clock patches.
> http://www.mail-archive.com/linux-samsung-soc@xxxxxxxxxxxxxxx/msg15860.html
>
> .../bindings/cpufreq/cpufreq-exynos5440.txt | 32 ++
> drivers/cpufreq/Kconfig.arm | 9 +
> drivers/cpufreq/Makefile | 1 +
> drivers/cpufreq/exynos5440-cpufreq.c | 450 ++++++++++++++++++++
> 4 files changed, 492 insertions(+), 0 deletions(-)
> 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..caa3f8d
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/cpufreq/cpufreq-exynos5440.txt
> @@ -0,0 +1,32 @@
> +
> +Exynos5440 cpufreq driver
> +-------------------
> +
> +Exynos5440 SoC cpufreq driver for CPU frequency scaling.
> +
> +Required properties:
> +- interrupts: Interrupt to know the completion of cpu frequency change.
> +- operating-points: 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.
> +- clocks: phandle of the clock from common clock binding. More description can
> + be found in Documentation/devicetree/bindings/clock/clock-bindings.txt.
> +
> +Optional properties:
> +- clock-latency: Clock transition latency in microsecond.
> +
> +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>;
> + operating-points = <
> + 1000000 975000
> + 800000 925000>;
> + clocks = <&clock 2>;
> + clock-latency = <100000>;
> + };
> +
> diff --git a/drivers/cpufreq/Kconfig.arm b/drivers/cpufreq/Kconfig.arm
> index 030ddf6..7ed9c4a 100644
> --- a/drivers/cpufreq/Kconfig.arm
> +++ b/drivers/cpufreq/Kconfig.arm
> @@ -77,6 +77,15 @@ config ARM_EXYNOS5250_CPUFREQ
> This adds the CPUFreq driver for Samsung EXYNOS5250
> SoC.
>
> +config ARM_EXYNOS5440_CPUFREQ
> + def_bool SOC_EXYNOS5440
> + depends on HAVE_CLK && PM_OPP && OF
> + 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_KIRKWOOD_CPUFREQ
> def_bool ARCH_KIRKWOOD && OF
> help
> diff --git a/drivers/cpufreq/Makefile b/drivers/cpufreq/Makefile
> index 863fd18..c841438 100644
> --- a/drivers/cpufreq/Makefile
> +++ b/drivers/cpufreq/Makefile
> @@ -52,6 +52,7 @@ 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_KIRKWOOD_CPUFREQ) += kirkwood-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..2dc43b1
> --- /dev/null
> +++ b/drivers/cpufreq/exynos5440-cpufreq.c
> @@ -0,0 +1,450 @@
> +/*
> + * Copyright (c) 2013 Samsung Electronics Co., Ltd.
> + * http://www.samsung.com
> + *
> + * Amit Daniel Kachhap <amit.daniel@xxxxxxxxxxx>
> + *
> + * 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.
> +*/
Add following here to get better prints from the driver:
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
> +
> +#include <linux/clk.h>
> +#include <linux/cpu.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>
Probably include of.h instead of above two?
> +#include <linux/opp.h>
> +#include <linux/slab.h>
> +
> +struct exynos_dvfs_data {
> + void __iomem *base;
> + struct resource *mem;
> + int irq;
> + struct clk *cpu_clk;
> + unsigned int cur_frequency;
> + unsigned int latency;
> + struct cpufreq_frequency_table *freq_table;
> + unsigned int freq_count;
> + struct device *dev;
> + struct work_struct irq_work;
> +};
> +
> +static struct exynos_dvfs_data *dvfs_info;
> +static DEFINE_MUTEX(cpufreq_lock);
> +static struct cpufreq_freqs freqs;
> +
> +static int init_div_table(void)
> +{
> + struct cpufreq_frequency_table *freq_tbl = dvfs_info->freq_table;
> + unsigned int tmp, clk_div, ema_div, freq, volt_id;
> + int i = 0;
> + struct opp *opp;
> +
> + for (i = 0; freq_tbl[i].frequency != CPUFREQ_TABLE_END; i++) {
> +
> + opp = opp_find_freq_exact(dvfs_info->dev,
> + freq_tbl[i].frequency * 1000, true);
> + if (IS_ERR(opp)) {
> + pr_err("failed to find valid OPP for %u KHZ\n",
> + freq_tbl[i].frequency);
> + return PTR_ERR(opp);
> + }
> +
> + 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 = opp_get_voltage(opp);
> + volt_id = (MAX_VOLTAGE - volt_id) / 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);
> + }
> +
> + return 0;
> +}
> +
> +void exynos_enable_dvfs(void)
> +{
> + unsigned int tmp, i, cpu;
> + struct cpufreq_frequency_table *freq_table = dvfs_info->freq_table;
> + /*Disable DVFS*/
Please give space after /* and before */ all over your driver.
> + __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 performance 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");
> + /*Assign the highest frequency*/
> + i = 0;
> + dvfs_info->cur_frequency = freq_table[i].frequency;
> + }
> +
> + 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, 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 (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;
> +
> + if (policy == NULL)
> + goto skip_work;
How can that be true? And if it can be, you will miss POSTCHANGE notifications
too.
> + 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 < dvfs_info->freq_count) {
What if index is greater than count? That's a problem, isn't it?
> + 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);
> +skip_work:
> + 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);
> + disable_irq_nosync(irq);
> + schedule_work(&dvfs_info->irq_work);
> + }
> + return IRQ_HANDLED;
> +}
> +
> +static void exynos_sort_descend_freq_table(void)
> +{
> + struct cpufreq_frequency_table *freq_tbl = dvfs_info->freq_table;
> + int i = 0, index;
> + unsigned int tmp_freq;
> +
> + /*
> + *Freq table is already in ascending order as it is created from
You need space after * here too :)
> + *OPP library, so just swap the elements to make it descending.
> + */
> + for (i = 0; i < dvfs_info->freq_count / 2; i++) {
> + index = dvfs_info->freq_count - i - 1;
> + tmp_freq = freq_tbl[i].frequency;
> + freq_tbl[i].frequency = freq_tbl[index].frequency;
> + freq_tbl[index].frequency = tmp_freq;
> + }
> +}
> +
> +static int exynos_cpufreq_cpu_init(struct cpufreq_policy *policy)
> +{
> +
> + policy->cur = dvfs_info->cur_frequency;
> + cpufreq_frequency_table_get_attr(dvfs_info->freq_table, policy->cpu);
> +
> + /* set the transition latency value */
> + policy->cpuinfo.transition_latency = dvfs_info->latency;
> +
> + 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)
probably calling it probe might make more sense?
> +{
> + int ret = -EINVAL;
> + struct device_node *np;
> +
> + np = of_find_compatible_node(NULL, NULL, "samsung,exynos5440-cpufreq");
> + if (IS_ERR(np))
!np ??
> + return -ENODEV;
> +
> + dvfs_info = kzalloc(sizeof(struct exynos_dvfs_data), GFP_KERNEL);
sizeof(*dvfs_info) ??
> + if (IS_ERR(dvfs_info)) {
IS_ERR_OR_NULL? But i believe kzalloc only returns NULL to show error, so
you may end up using if(!dvfs_info)
> + ret = -ENOMEM;
> + goto err_mem_data;
> + }
> +
> + dvfs_info->base = of_iomap(np, 0);
> + if (IS_ERR(dvfs_info->base)) {
same here too..
> + pr_err("No cpufreq memory map found\n");
> + ret = -ENODEV;
> + goto err_map;
> + }
> +
> + dvfs_info->irq = irq_of_parse_and_map(np, 0);
> +
can remove blank line.
> + if (dvfs_info->irq == 0) {
> + pr_err("No cpufreq irq found\n");
> + ret = -ENODEV;
> + goto err_irq_parse;
> + }
> +
> + dvfs_info->dev = get_cpu_device(0);
What about using this dev instance to call devm_*** routines everywhere in init.
> + if (IS_ERR(dvfs_info->dev)) {
> + pr_err("failed to get cpu0 device\n");
> + ret = -ENODEV;
> + goto err_irq_parse;
> + }
> +
> + dvfs_info->dev->of_node = np;
So you are setting cpufreq node as node of cpu, I don't know if this is a
good idea. In that case it would be better to create the cpu node instead
and put the table into it.
> + ret = of_init_opp_table(dvfs_info->dev);
> + if (ret) {
> + pr_err("failed to init OPP table: %d\n", ret);
> + goto err_irq_parse;
> + }
> +
> + ret = opp_init_cpufreq_table(dvfs_info->dev, &dvfs_info->freq_table);
> + if (ret) {
> + pr_err("failed to init cpufreq table: %d\n", ret);
> + goto err_irq_parse;
> + }
> + dvfs_info->freq_count = opp_get_opp_count(dvfs_info->dev);
> + exynos_sort_descend_freq_table();
> +
> + if (of_property_read_u32(np, "clock-latency", &dvfs_info->latency))
> + dvfs_info->latency = DEF_TRANS_LATENCY;
> +
> + dvfs_info->cpu_clk = of_clk_get(np, 0);
> + if (IS_ERR(dvfs_info->cpu_clk)) {
> + pr_err("Failed to get cpu clock\n");
> + ret = PTR_ERR(dvfs_info->cpu_clk);
> + goto err_clk_get;
> + }
> +
> + dvfs_info->cur_frequency = clk_get_rate(dvfs_info->cpu_clk);
> + if (!dvfs_info->cur_frequency) {
> + pr_err("Failed to get clock rate\n");
> + ret = -EINVAL;
> + goto err_clk_get_rate;
> + }
> + dvfs_info->cur_frequency /= 1000;
> +
> + 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_clk_get_rate;
> + }
> +
> + ret = init_div_table();
> + if (ret) {
> + pr_err("Failed to initialise div table\n");
s/initialise/initialize
> + goto err_div_table;
> + }
> +
> + exynos_enable_dvfs();
> + ret = cpufreq_register_driver(&exynos_driver);
> + if (ret) {
> + pr_err("%s: failed to register cpufreq driver\n", __func__);
> + goto err_div_table;
> + }
> +
> + of_node_put(np);
> +
> + pr_info("exynos5440 DVFS initialised.\n");
> +
> + return 0;
> +
> +err_div_table:
> + free_irq(dvfs_info->irq, dvfs_info);
> +err_clk_get_rate:
> + clk_put(dvfs_info->cpu_clk);
> +err_clk_get:
> + opp_free_cpufreq_table(dvfs_info->dev, &dvfs_info->freq_table);
> +err_irq_parse:
> + iounmap(dvfs_info->base);
> +err_map:
> + kfree(dvfs_info);
> +err_mem_data:
> + of_node_put(np);
> + pr_err("%s: failed initialization\n", __func__);
> + return ret;
> +}
> +late_initcall(exynos_cpufreq_init);
> --
> 1.7.1
>
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