On Mon, Feb 04, 2013 at 10:51:42AM +0800, Shawn Guo wrote:
> Add an imx6q-cpufreq driver for Freescale i.MX6Q SoC to handle the
> hardware specific frequency and voltage scaling requirements.
>
> The driver supports module build and is instantiated by the platform
> device/driver mechanism, so that it will not be instantiated on other
> platforms, as IMX is built with multiplatform support.
>
> Signed-off-by: Shawn Guo <shawn.guo@xxxxxxxxxx>
> Reviewed-by: Viresh Kumar <viresh.kumar@xxxxxxxxxx>
> ---
> Changes since v4:
> * Use regulator API to handle voltage latency
>
> Rafael,
>
> I generated the patch against your bleeding-edge branch, so it should
> be applied cleanly.
>
> Shawn
>
> drivers/cpufreq/Kconfig.arm | 9 ++
> drivers/cpufreq/Makefile | 1 +
> drivers/cpufreq/imx6q-cpufreq.c | 331 +++++++++++++++++++++++++++++++++++++++
> 3 files changed, 341 insertions(+)
> create mode 100644 drivers/cpufreq/imx6q-cpufreq.c
>
> diff --git a/drivers/cpufreq/Kconfig.arm b/drivers/cpufreq/Kconfig.arm
> index ffe55b8..c65226c 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_IMX6Q_CPUFREQ
> + tristate "Freescale i.MX6Q cpufreq support"
> + depends on SOC_IMX6Q
> + depends on REGULATOR_ANATOP
> + help
> + This adds cpufreq driver support for Freescale i.MX6Q SOC.
> +
> + If in doubt, say N.
> +
> config ARM_SPEAR_CPUFREQ
> bool "SPEAr CPUFreq support"
> depends on PLAT_SPEAR
> diff --git a/drivers/cpufreq/Makefile b/drivers/cpufreq/Makefile
> index e2a5da7..93610b2 100644
> --- a/drivers/cpufreq/Makefile
> +++ b/drivers/cpufreq/Makefile
> @@ -54,6 +54,7 @@ obj-$(CONFIG_ARM_EXYNOS5250_CPUFREQ) += exynos5250-cpufreq.o
> obj-$(CONFIG_ARM_OMAP2PLUS_CPUFREQ) += omap-cpufreq.o
> obj-$(CONFIG_ARM_SPEAR_CPUFREQ) += spear-cpufreq.o
> obj-$(CONFIG_ARM_HIGHBANK_CPUFREQ) += highbank-cpufreq.o
> +obj-$(CONFIG_ARM_IMX6Q_CPUFREQ) += imx6q-cpufreq.o
>
> ##################################################################################
> # PowerPC platform drivers
> diff --git a/drivers/cpufreq/imx6q-cpufreq.c b/drivers/cpufreq/imx6q-cpufreq.c
> new file mode 100644
> index 0000000..f73b245
> --- /dev/null
> +++ b/drivers/cpufreq/imx6q-cpufreq.c
> @@ -0,0 +1,331 @@
> +/*
> + * Copyright (C) 2013 Freescale Semiconductor, Inc.
> + *
> + * 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/delay.h>
> +#include <linux/err.h>
> +#include <linux/module.h>
> +#include <linux/of.h>
> +#include <linux/opp.h>
> +#include <linux/platform_device.h>
> +#include <linux/regulator/consumer.h>
> +
> +#define PU_SOC_VOLTAGE_NORMAL 1250000
> +#define PU_SOC_VOLTAGE_HIGH 1275000
> +#define FREQ_1P2_GHZ 1200000000
> +
> +static struct regulator *arm_reg;
> +static struct regulator *pu_reg;
> +static struct regulator *soc_reg;
> +
> +static struct clk *arm_clk;
> +static struct clk *pll1_sys_clk;
> +static struct clk *pll1_sw_clk;
> +static struct clk *step_clk;
> +static struct clk *pll2_pfd2_396m_clk;
> +
> +static struct device *cpu_dev;
> +static struct cpufreq_frequency_table *freq_table;
> +static unsigned int transition_latency;
> +
> +static int imx6q_verify_speed(struct cpufreq_policy *policy)
> +{
> + return cpufreq_frequency_table_verify(policy, freq_table);
> +}
> +
> +static unsigned int imx6q_get_speed(unsigned int cpu)
> +{
> + return clk_get_rate(arm_clk) / 1000;
> +}
> +
> +static int imx6q_set_target(struct cpufreq_policy *policy,
> + unsigned int target_freq, unsigned int relation)
> +{
> + struct cpufreq_freqs freqs;
> + struct opp *opp;
> + unsigned long freq_hz, volt, volt_old;
> + unsigned int index, cpu;
> + int ret;
> +
> + ret = cpufreq_frequency_table_target(policy, freq_table, target_freq,
> + relation, &index);
> + if (ret) {
> + dev_err(cpu_dev, "failed to match target frequency %d: %d\n",
> + target_freq, ret);
> + return ret;
> + }
> +
> + freqs.new = freq_table[index].frequency;
> + freq_hz = freqs.new * 1000;
> + freqs.old = clk_get_rate(arm_clk) / 1000;
> +
> + if (freqs.old == freqs.new)
> + return 0;
> +
> + for_each_online_cpu(cpu) {
> + freqs.cpu = cpu;
> + cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE);
> + }
> +
> + rcu_read_lock();
> + opp = opp_find_freq_ceil(cpu_dev, &freq_hz);
> + if (IS_ERR(opp)) {
> + rcu_read_unlock();
> + dev_err(cpu_dev, "failed to find OPP for %ld\n", freq_hz);
> + return PTR_ERR(opp);
> + }
> +
> + volt = opp_get_voltage(opp);
> + rcu_read_unlock();
> + volt_old = regulator_get_voltage(arm_reg);
> +
> + dev_dbg(cpu_dev, "%u MHz, %ld mV --> %u MHz, %ld mV\n",
> + freqs.old / 1000, volt_old / 1000,
> + freqs.new / 1000, volt / 1000);
> +
> + /* scaling up? scale voltage before frequency */
> + if (freqs.new > freqs.old) {
> + ret = regulator_set_voltage_tol(arm_reg, volt, 0);
> + if (ret) {
> + dev_err(cpu_dev,
> + "failed to scale vddarm up: %d\n", ret);
> + return ret;
> + }
> +
> + /*
> + * Need to increase vddpu and vddsoc for safety
> + * if we are about to run at 1.2 GHz.
> + */
> + if (freqs.new == FREQ_1P2_GHZ / 1000) {
> + regulator_set_voltage_tol(pu_reg,
> + PU_SOC_VOLTAGE_HIGH, 0);
> + regulator_set_voltage_tol(soc_reg,
> + PU_SOC_VOLTAGE_HIGH, 0);
> + }
> + }
> +
> + /*
> + * The setpoints are selected per PLL/PDF frequencies, so we need to
> + * reprogram PLL for frequency scaling. The procedure of reprogramming
> + * PLL1 is as below.
> + *
> + * - Enable pll2_pfd2_396m_clk and reparent pll1_sw_clk to it
> + * - Disable pll1_sys_clk and reprogram it
> + * - Enable pll1_sys_clk and reparent pll1_sw_clk back to it
> + * - Disable pll2_pfd2_396m_clk
> + */
> + clk_prepare_enable(pll2_pfd2_396m_clk);
> + clk_set_parent(step_clk, pll2_pfd2_396m_clk);
> + clk_set_parent(pll1_sw_clk, step_clk);
> + clk_prepare_enable(pll1_sys_clk);
> + if (freq_hz > clk_get_rate(pll2_pfd2_396m_clk)) {
> + clk_disable_unprepare(pll1_sys_clk);
> + clk_set_rate(pll1_sys_clk, freqs.new * 1000);
> + clk_prepare_enable(pll1_sys_clk);
> + clk_set_parent(pll1_sw_clk, pll1_sys_clk);
> + clk_disable_unprepare(pll2_pfd2_396m_clk);
> + } else {
> + /*
> + * Disable pll1_sys_clk if pll2_pfd2_396m_clk is sufficient
> + * to provide the frequency.
> + */
> + clk_disable_unprepare(pll1_sys_clk);
> + }
Seems like we will get pll2_pfd2_396m_clk's use count mismatch? As every time cpu freq is changed, pll2_pfd2_396m_clk will be added at the beginning of this code piece, but only decreased when cpu freq > 396M, so everytime cpu freq changed to 396M, this pll2_pfd2_396m_clk will in increased?
> +
> + /* Ensure the arm clock divider is what we expect */
> + ret = clk_set_rate(arm_clk, freqs.new * 1000);
> + if (ret) {
> + dev_err(cpu_dev, "failed to set clock rate: %d\n", ret);
> + regulator_set_voltage_tol(arm_reg, volt_old, 0);
> + return ret;
> + }
> +
> + /* scaling down? scale voltage after frequency */
> + if (freqs.new < freqs.old) {
> + ret = regulator_set_voltage_tol(arm_reg, volt, 0);
> + if (ret)
> + dev_warn(cpu_dev,
> + "failed to scale vddarm down: %d\n", ret);
> +
> + if (freqs.old == FREQ_1P2_GHZ / 1000) {
> + regulator_set_voltage_tol(pu_reg,
> + PU_SOC_VOLTAGE_NORMAL, 0);
> + regulator_set_voltage_tol(soc_reg,
> + PU_SOC_VOLTAGE_NORMAL, 0);
> + }
> + }
> +
> + for_each_online_cpu(cpu) {
> + freqs.cpu = cpu;
> + cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE);
> + }
> +
Should we need to update the percpu loops_per_jiffy variable and global loops_per_jiffy? As the udelay and mdelay will rely on this global loops_per_jiffy? Or the latest kernel has handle it in other place such as cpufreq common driver? I remembered that common cpufreq driver only handle the noSMP case.
Anson
> + return 0;
> +}
> +
> +static int imx6q_cpufreq_init(struct cpufreq_policy *policy)
> +{
> + int ret;
> +
> + ret = cpufreq_frequency_table_cpuinfo(policy, freq_table);
> + if (ret) {
> + dev_err(cpu_dev, "invalid frequency table: %d\n", ret);
> + return ret;
> + }
> +
> + policy->cpuinfo.transition_latency = transition_latency;
> + policy->cur = clk_get_rate(arm_clk) / 1000;
> + cpumask_setall(policy->cpus);
> + cpufreq_frequency_table_get_attr(freq_table, policy->cpu);
> +
> + return 0;
> +}
> +
> +static int imx6q_cpufreq_exit(struct cpufreq_policy *policy)
> +{
> + cpufreq_frequency_table_put_attr(policy->cpu);
> + return 0;
> +}
> +
> +static struct freq_attr *imx6q_cpufreq_attr[] = {
> + &cpufreq_freq_attr_scaling_available_freqs,
> + NULL,
> +};
> +
> +static struct cpufreq_driver imx6q_cpufreq_driver = {
> + .verify = imx6q_verify_speed,
> + .target = imx6q_set_target,
> + .get = imx6q_get_speed,
> + .init = imx6q_cpufreq_init,
> + .exit = imx6q_cpufreq_exit,
> + .name = "imx6q-cpufreq",
> + .attr = imx6q_cpufreq_attr,
> +};
> +
> +static int imx6q_cpufreq_probe(struct platform_device *pdev)
> +{
> + struct device_node *np;
> + struct opp *opp;
> + unsigned long min_volt, max_volt;
> + int num, ret;
> +
> + cpu_dev = &pdev->dev;
> +
> + np = of_find_node_by_path("/cpus/cpu@0");
> + if (!np) {
> + dev_err(cpu_dev, "failed to find cpu0 node\n");
> + return -ENOENT;
> + }
> +
> + cpu_dev->of_node = np;
> +
> + arm_clk = devm_clk_get(cpu_dev, "arm");
> + pll1_sys_clk = devm_clk_get(cpu_dev, "pll1_sys");
> + pll1_sw_clk = devm_clk_get(cpu_dev, "pll1_sw");
> + step_clk = devm_clk_get(cpu_dev, "step");
> + pll2_pfd2_396m_clk = devm_clk_get(cpu_dev, "pll2_pfd2_396m");
> + if (IS_ERR(arm_clk) || IS_ERR(pll1_sys_clk) || IS_ERR(pll1_sw_clk) ||
> + IS_ERR(step_clk) || IS_ERR(pll2_pfd2_396m_clk)) {
> + dev_err(cpu_dev, "failed to get clocks\n");
> + ret = -ENOENT;
> + goto put_node;
> + }
> +
> + arm_reg = devm_regulator_get(cpu_dev, "arm");
> + pu_reg = devm_regulator_get(cpu_dev, "pu");
> + soc_reg = devm_regulator_get(cpu_dev, "soc");
> + if (!arm_reg || !pu_reg || !soc_reg) {
> + dev_err(cpu_dev, "failed to get regulators\n");
> + ret = -ENOENT;
> + goto put_node;
> + }
> +
> + /* We expect an OPP table supplied by platform */
> + num = opp_get_opp_count(cpu_dev);
> + if (num < 0) {
> + ret = num;
> + dev_err(cpu_dev, "no OPP table is found: %d\n", ret);
> + goto put_node;
> + }
> +
> + ret = opp_init_cpufreq_table(cpu_dev, &freq_table);
> + if (ret) {
> + dev_err(cpu_dev, "failed to init cpufreq table: %d\n", ret);
> + goto put_node;
> + }
> +
> + if (of_property_read_u32(np, "clock-latency", &transition_latency))
> + transition_latency = CPUFREQ_ETERNAL;
> +
> + /*
> + * OPP is maintained in order of increasing frequency, and
> + * freq_table initialised from OPP is therefore sorted in the
> + * same order.
> + */
> + rcu_read_lock();
> + opp = opp_find_freq_exact(cpu_dev,
> + freq_table[0].frequency * 1000, true);
> + min_volt = opp_get_voltage(opp);
> + opp = opp_find_freq_exact(cpu_dev,
> + freq_table[--num].frequency * 1000, true);
> + max_volt = opp_get_voltage(opp);
> + rcu_read_unlock();
> + ret = regulator_set_voltage_time(arm_reg, min_volt, max_volt);
> + if (ret > 0)
> + transition_latency += ret * 1000;
> +
> + /* Count vddpu and vddsoc latency in for 1.2 GHz support */
> + if (freq_table[num].frequency == FREQ_1P2_GHZ / 1000) {
> + ret = regulator_set_voltage_time(pu_reg, PU_SOC_VOLTAGE_NORMAL,
> + PU_SOC_VOLTAGE_HIGH);
> + if (ret > 0)
> + transition_latency += ret * 1000;
> + ret = regulator_set_voltage_time(soc_reg, PU_SOC_VOLTAGE_NORMAL,
> + PU_SOC_VOLTAGE_HIGH);
> + if (ret > 0)
> + transition_latency += ret * 1000;
> + }
> +
> + ret = cpufreq_register_driver(&imx6q_cpufreq_driver);
> + if (ret) {
> + dev_err(cpu_dev, "failed register driver: %d\n", ret);
> + goto free_freq_table;
> + }
> +
> + of_node_put(np);
> + return 0;
> +
> +free_freq_table:
> + opp_free_cpufreq_table(cpu_dev, &freq_table);
> +put_node:
> + of_node_put(np);
> + return ret;
> +}
> +
> +static int imx6q_cpufreq_remove(struct platform_device *pdev)
> +{
> + cpufreq_unregister_driver(&imx6q_cpufreq_driver);
> + opp_free_cpufreq_table(cpu_dev, &freq_table);
> +
> + return 0;
> +}
> +
> +static struct platform_driver imx6q_cpufreq_platdrv = {
> + .driver = {
> + .name = "imx6q-cpufreq",
> + .owner = THIS_MODULE,
> + },
> + .probe = imx6q_cpufreq_probe,
> + .remove = imx6q_cpufreq_remove,
> +};
> +module_platform_driver(imx6q_cpufreq_platdrv);
> +
> +MODULE_AUTHOR("Shawn Guo <shawn.guo@xxxxxxxxxx>");
> +MODULE_DESCRIPTION("Freescale i.MX6Q cpufreq driver");
> +MODULE_LICENSE("GPL");
> --
> 1.7.9.5
>
>
>
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