| Message ID | 20161122010616.91307-1-code@mmayer.net (mailing list archive) |
|---|---|
| State | Superseded, archived |
| Headers | show |
On 21 November 2016 at 17:06, Markus Mayer <code@mmayer.net> wrote: > From: Markus Mayer <mmayer@broadcom.com> > > This CPUfreq driver provides basic frequency scaling for older Broadcom > STB SoCs that do not use AVS firmware with DVFS support. There is no > support for voltage scaling. > > Signed-off-by: Markus Mayer <mmayer@broadcom.com> > --- I meant to add this to the patch: Changes since v2: - removed brcmstb_cpufreq_get(), using cpufreq_generic_get() instead - replaced calls to cpufreq_table_validate_and_show() and cpumask_setall() with a call to cpufreq_generic_init() - removed code that would set policy->cur, leaving it up to the framework to do so - simplified show_brcmstb_safe_freq(), re-using already existing data > drivers/cpufreq/Kconfig.arm | 12 ++ > drivers/cpufreq/Makefile | 1 + > drivers/cpufreq/brcmstb-cpufreq.c | 381 ++++++++++++++++++++++++++++++++++++++ > 3 files changed, 394 insertions(+) > create mode 100644 drivers/cpufreq/brcmstb-cpufreq.c > > diff --git a/drivers/cpufreq/Kconfig.arm b/drivers/cpufreq/Kconfig.arm > index 920c469..36422af 100644 > --- a/drivers/cpufreq/Kconfig.arm > +++ b/drivers/cpufreq/Kconfig.arm > @@ -33,6 +33,18 @@ config ARM_BRCMSTB_AVS_CPUFREQ_DEBUG > > If in doubt, say N. > > +config ARM_BRCMSTB_CPUFREQ > + tristate "Broadcom STB CPUfreq driver" > + depends on ARCH_BRCMSTB || COMPILE_TEST > + default y > + help > + Some Broadcom SoCs offer multiple operating frequencies that CPUfreq > + can take advantage of to improve energy efficiency. > + > + Say Y, if you have a supported Broadcom SoC. If your Broadcom SoC > + has AVS firmware with support for frequency and voltage scaling, > + say N here and enable ARM_BRCMSTB_AVS_CPUFREQ instead. > + > config ARM_DT_BL_CPUFREQ > tristate "Generic probing via DT for ARM big LITTLE CPUfreq driver" > depends on ARM_BIG_LITTLE_CPUFREQ && OF > diff --git a/drivers/cpufreq/Makefile b/drivers/cpufreq/Makefile > index 1e46c39..23700aa 100644 > --- a/drivers/cpufreq/Makefile > +++ b/drivers/cpufreq/Makefile > @@ -52,6 +52,7 @@ obj-$(CONFIG_ARM_BIG_LITTLE_CPUFREQ) += arm_big_little.o > obj-$(CONFIG_ARM_DT_BL_CPUFREQ) += arm_big_little_dt.o > > obj-$(CONFIG_ARM_BRCMSTB_AVS_CPUFREQ) += brcmstb-avs-cpufreq.o > +obj-$(CONFIG_ARM_BRCMSTB_CPUFREQ) += brcmstb-cpufreq.o > obj-$(CONFIG_ARCH_DAVINCI) += davinci-cpufreq.o > obj-$(CONFIG_UX500_SOC_DB8500) += dbx500-cpufreq.o > obj-$(CONFIG_ARM_EXYNOS5440_CPUFREQ) += exynos5440-cpufreq.o > diff --git a/drivers/cpufreq/brcmstb-cpufreq.c b/drivers/cpufreq/brcmstb-cpufreq.c > new file mode 100644 > index 0000000..0270789 > --- /dev/null > +++ b/drivers/cpufreq/brcmstb-cpufreq.c > @@ -0,0 +1,381 @@ > +/* > + * CPU frequency scaling for Broadcom set top box SoCs > + * > + * Copyright (c) 2016 Broadcom > + * > + * 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 version 2. > + * > + * This program is distributed "as is" WITHOUT ANY WARRANTY of any > + * kind, whether express or implied; without even the implied warranty > + * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the > + * GNU General Public License for more details. > + */ > + > +#include <linux/clk.h> > +#include <linux/clk-provider.h> > +#include <linux/cpufreq.h> > +#include <linux/module.h> > +#include <linux/of_address.h> > +#include <linux/platform_device.h> > + > +#define BRCMSTB_CPUFREQ_PREFIX "brcmstb" > +#define BRCMSTB_CPUFREQ_NAME BRCMSTB_CPUFREQ_PREFIX "-cpufreq" > + > +/* We search for these compatible strings. */ > +#define BRCMSTB_DT_CPU_CLK_CTRL "brcm,brcmstb-cpu-clk-div" > +#define BRCMSTB_DT_MEMC_DDR "brcm,brcmstb-memc-ddr" > +#define BRCM_AVS_CPU_DATA "brcm,avs-cpu-data-mem" > + > +/* We also need a few clocks in device tree. These are node names. */ > +#define BRCMSTB_CLK_MDIV_CH0 "cpu_mdiv_ch0" > +#define BRCMSTB_CLK_NDIV_INT "cpu_ndiv_int" > +#define BRCMSTB_CLK_SW_SCB "sw_scb" > + > +#define BRCMSTB_TBL_SAFE_MODE BIT(0) > +#define BRCMSTB_REG_SAFE_MODE BIT(4) > + > +#define TRANSITION_LATENCY (25 * 1000) /* 25 us */ > + > +/* This is as low as we'll go in the frequency table. */ > +#define MIN_CPU_FREQ (100 * 1000) /* in kHz */ > + > +struct private_data { > + void __iomem *cpu_clk_ctrl_reg; > + struct device *dev; > +}; > + > +/* Count the active memory controllers in the system. */ > +static int count_memory_controllers(void) > +{ > + struct device_node *np = NULL; > + int i = 0; > + > + do { > + np = of_find_compatible_node(np, NULL, BRCMSTB_DT_MEMC_DDR); > + if (of_device_is_available(np)) > + i++; > + of_node_put(np); > + } while (np); > + > + return i; > +} > + > +static int get_frequencies(const struct cpufreq_policy *policy, > + unsigned int *vco_freq, unsigned int *cpu_freq, > + unsigned int *scb_freq) > +{ > + struct clk *cpu_ndiv_int, *sw_scb; > + > + cpu_ndiv_int = __clk_lookup(BRCMSTB_CLK_NDIV_INT); > + if (!cpu_ndiv_int) > + return -ENODEV; > + > + sw_scb = __clk_lookup(BRCMSTB_CLK_SW_SCB); > + if (!sw_scb) > + return -ENODEV; > + > + /* return frequencies in kHz */ > + *vco_freq = clk_get_rate(cpu_ndiv_int) / 1000; > + *cpu_freq = clk_get_rate(policy->clk) / 1000; > + *scb_freq = clk_get_rate(sw_scb) / 1000; > + > + return 0; > +} > + > +/* > + * Safe mode: When set, the CPU's bus unit is being throttled. This is done to > + * avoid buffer overflows when the CPU-to-bus-clock ratio is low. > + * > + * The formula as to what constitutes a low CPU-to-bus-clock ratio takes into > + * account the number of memory controllers active in the system and the SCB > + * frequency. More memory controllers means safe mode is required starting at > + * higher frequencies. > + * > + * For 1 memory controller, cpu_freq/scb_freq must be greater than or equal to > + * 2 to not require safe mode. > + * > + * For 2 or 3 memory controllers, cpu_freq/scb_freq must be greater than or > + * equal 3 to not require safe mode. > + */ > + > +static int freq_requires_safe_mode(unsigned int cpu_freq, unsigned int scb_freq, > + int num_memc) > +{ > + unsigned int safe_ratio; > + > + switch (num_memc) { > + case 1: > + safe_ratio = 2; > + break; > + case 2: > + case 3: > + safe_ratio = 3; > + break; > + default: > + return -EINVAL; > + } > + > + return ((cpu_freq / scb_freq) < safe_ratio); > +} > + > +static struct cpufreq_frequency_table * > +brcmstb_get_freq_table(const struct cpufreq_policy *policy) > +{ > + unsigned int cpu_freq, vco_freq, scb_freq, mdiv, init_mdiv, f; > + struct cpufreq_frequency_table *table; > + struct private_data *priv; > + int num_memc, ret; > + unsigned int i = 0; > + > + ret = get_frequencies(policy, &vco_freq, &cpu_freq, &scb_freq); > + if (ret) > + return ERR_PTR(ret); > + > + priv = policy->driver_data; > + num_memc = count_memory_controllers(); > + > + /* Calculate the initial mdiv value. We'll increment mdiv from here. */ > + init_mdiv = vco_freq / cpu_freq; > + > + /* Count how many frequencies we'll offer. */ > + f = cpu_freq; > + for (mdiv = init_mdiv; f >= MIN_CPU_FREQ; mdiv++, f = vco_freq / mdiv) { > + /* We only want to use "whole" MHz. */ > + if ((f % 1000) == 0) > + i++; > + } > + > + table = devm_kzalloc(priv->dev, (i + 1) * sizeof(*table), GFP_KERNEL); > + if (!table) > + return ERR_PTR(-ENOMEM); > + > + /* Now, fill the table. */ > + f = cpu_freq; > + i = 0; > + for (mdiv = init_mdiv; f >= MIN_CPU_FREQ; mdiv++, f = vco_freq / mdiv) { > + if ((f % 1000) == 0) { > + table[i].frequency = f; > + ret = freq_requires_safe_mode(f, scb_freq, num_memc); > + if (ret < 0) > + return ERR_PTR(ret); > + if (ret > 0) > + table[i].driver_data |= BRCMSTB_TBL_SAFE_MODE; > + i++; > + } > + } > + table[i].frequency = CPUFREQ_TABLE_END; > + > + return table; > +} > + > +static int brcmstb_target_index(struct cpufreq_policy *policy, > + unsigned int index) > +{ > + struct cpufreq_frequency_table *entry; > + struct private_data *priv; > + int ret, safe_mode_needed; > + u32 reg; > + > + priv = policy->driver_data; > + entry = &policy->freq_table[index]; > + safe_mode_needed = entry->driver_data & BRCMSTB_TBL_SAFE_MODE; > + > + reg = readl(priv->cpu_clk_ctrl_reg); > + if (safe_mode_needed && !(reg & BRCMSTB_REG_SAFE_MODE)) { > + reg |= BRCMSTB_REG_SAFE_MODE; > + writel(reg, priv->cpu_clk_ctrl_reg); > + } > + ret = clk_set_rate(policy->clk, entry->frequency * 1000); > + if (!ret && !safe_mode_needed && (reg & BRCMSTB_REG_SAFE_MODE)) { > + reg &= ~BRCMSTB_REG_SAFE_MODE; > + writel(reg, priv->cpu_clk_ctrl_reg); > + } > + > + return ret; > +} > + > +/* > + * All initialization code that we only want to execute once goes here. Setup > + * code that can be re-tried on every core (if it failed before) can go into > + * brcm_avs_cpufreq_init(). > + */ > +static int brcmstb_prepare_init(struct platform_device *pdev) > +{ > + struct private_data *priv; > + struct resource *res; > + struct device *dev; > + > + /* > + * If the BRCM STB AVS CPUfreq driver is supported, we bail, so that > + * the more modern approach implementing DVFS in firmware can be used. > + */ > + if (IS_ENABLED(CONFIG_ARM_BRCM_AVS_CPUFREQ)) { > + struct device_node *np; > + > + np = of_find_compatible_node(NULL, NULL, BRCM_AVS_CPU_DATA); > + if (np) { > + of_node_put(np); > + return -ENXIO; > + } > + } > + > + dev = &pdev->dev; > + > + priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL); > + if (!priv) > + return -ENOMEM; > + > + res = platform_get_resource(pdev, IORESOURCE_MEM, 0); > + priv->cpu_clk_ctrl_reg = devm_ioremap_resource(dev, res); > + if (IS_ERR(priv->cpu_clk_ctrl_reg)) { > + dev_err(dev, "couldn't map DT entry %s\n", > + BRCMSTB_DT_CPU_CLK_CTRL); > + return -ENODEV; > + } > + > + priv->dev = dev; > + platform_set_drvdata(pdev, priv); > + > + return 0; > +} > + > +static int brcmstb_cpu_init(struct cpufreq_policy *policy) > +{ > + struct cpufreq_frequency_table *freq_table; > + struct platform_device *pdev; > + struct private_data *priv; > + struct clk *cpu_mdiv_ch0; > + struct device *dev; > + int ret; > + > + cpu_mdiv_ch0 = __clk_lookup(BRCMSTB_CLK_MDIV_CH0); > + if (!cpu_mdiv_ch0) > + return -ENODEV; > + > + pdev = cpufreq_get_driver_data(); > + priv = platform_get_drvdata(pdev); > + dev = &pdev->dev; > + > + policy->clk = cpu_mdiv_ch0; > + policy->driver_data = priv; > + > + freq_table = brcmstb_get_freq_table(policy); > + if (IS_ERR(freq_table)) { > + ret = PTR_ERR(freq_table); > + dev_err(dev, "Couldn't determine frequency table (%d).\n", ret); > + if (ret == -EINVAL) > + dev_emerg(dev, > + "Invalid number of memory controllers -- %d!\n", > + count_memory_controllers()); > + return ret; > + } > + > + ret = cpufreq_generic_init(policy, freq_table, TRANSITION_LATENCY); > + if (!ret) > + dev_info(dev, "registered\n"); > + > + return ret; > +} > + > +/* Shows the number of memory controllers. */ > +static ssize_t show_brcmstb_num_memc(struct cpufreq_policy *policy, char *buf) > +{ > + return sprintf(buf, "%u\n", count_memory_controllers()); > +} > + > +/* Shows vco_freq, cpu_freq, and scb_freq in kHz. */ > +static ssize_t show_brcmstb_freqs(struct cpufreq_policy *policy, char *buf) > +{ > + unsigned int vco_freq, cpu_freq, scb_freq; > + int ret; > + > + ret = get_frequencies(policy, &vco_freq, &cpu_freq, &scb_freq); > + if (ret) > + return sprintf(buf, "<unknown>\n"); > + > + return sprintf(buf, "%u %u %u\n", vco_freq, cpu_freq, scb_freq); > +} > + > +/* Shows the lowest frequency (in kHz) that can be used without "safe mode". */ > +static ssize_t show_brcmstb_safe_freq(struct cpufreq_policy *policy, char *buf) > +{ > + struct cpufreq_frequency_table *entry; > + unsigned int safe_freq = 0; > + > + cpufreq_for_each_valid_entry(entry, policy->freq_table) { > + if (!(entry->driver_data & BRCMSTB_TBL_SAFE_MODE)) > + safe_freq = entry->frequency; > + } > + > + return sprintf(buf, "%u\n", safe_freq); > +} > + > +cpufreq_freq_attr_ro(brcmstb_num_memc); > +cpufreq_freq_attr_ro(brcmstb_freqs); > +cpufreq_freq_attr_ro(brcmstb_safe_freq); > + > +static struct freq_attr *brcmstb_cpufreq_attr[] = { > + &cpufreq_freq_attr_scaling_available_freqs, > + &brcmstb_num_memc, > + &brcmstb_freqs, > + &brcmstb_safe_freq, > + NULL > +}; > + > +static struct cpufreq_driver brcmstb_driver = { > + .flags = CPUFREQ_NEED_INITIAL_FREQ_CHECK, > + .verify = cpufreq_generic_frequency_table_verify, > + .target_index = brcmstb_target_index, > + .get = cpufreq_generic_get, > + .init = brcmstb_cpu_init, > + .attr = brcmstb_cpufreq_attr, > + .name = BRCMSTB_CPUFREQ_PREFIX, > +}; > + > +static int brcmstb_cpufreq_probe(struct platform_device *pdev) > +{ > + int ret; > + > + ret = brcmstb_prepare_init(pdev); > + if (ret) > + return ret; > + > + brcmstb_driver.driver_data = pdev; > + > + return cpufreq_register_driver(&brcmstb_driver); > +} > + > +static int brcmstb_cpufreq_remove(struct platform_device *pdev) > +{ > + int ret; > + > + ret = cpufreq_unregister_driver(&brcmstb_driver); > + if (ret) > + return ret; > + > + platform_set_drvdata(pdev, NULL); > + > + return 0; > +} > + > +static const struct of_device_id brcmstb_cpufreq_match[] = { > + { .compatible = BRCMSTB_DT_CPU_CLK_CTRL }, > + { } > +}; > +MODULE_DEVICE_TABLE(platform, brcmstb_cpufreq_match); > + > +static struct platform_driver brcmstb_cpufreq_platdrv = { > + .driver = { > + .name = BRCMSTB_CPUFREQ_NAME, > + .of_match_table = brcmstb_cpufreq_match, > + }, > + .probe = brcmstb_cpufreq_probe, > + .remove = brcmstb_cpufreq_remove, > +}; > +module_platform_driver(brcmstb_cpufreq_platdrv); > + > +MODULE_AUTHOR("Markus Mayer <mmayer@broadcom.com>"); > +MODULE_DESCRIPTION("CPUfreq driver for Broadcom STB SoCs"); > +MODULE_LICENSE("GPL"); > -- > 2.7.4 > -- To unsubscribe from this list: send the line "unsubscribe linux-pm" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On 21-11-16, 17:06, Markus Mayer wrote: > From: Markus Mayer <mmayer@broadcom.com> > > This CPUfreq driver provides basic frequency scaling for older Broadcom > STB SoCs that do not use AVS firmware with DVFS support. There is no > support for voltage scaling. > > Signed-off-by: Markus Mayer <mmayer@broadcom.com> > --- > drivers/cpufreq/Kconfig.arm | 12 ++ > drivers/cpufreq/Makefile | 1 + > drivers/cpufreq/brcmstb-cpufreq.c | 381 ++++++++++++++++++++++++++++++++++++++ > 3 files changed, 394 insertions(+) > create mode 100644 drivers/cpufreq/brcmstb-cpufreq.c Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
diff --git a/drivers/cpufreq/Kconfig.arm b/drivers/cpufreq/Kconfig.arm index 920c469..36422af 100644 --- a/drivers/cpufreq/Kconfig.arm +++ b/drivers/cpufreq/Kconfig.arm @@ -33,6 +33,18 @@ config ARM_BRCMSTB_AVS_CPUFREQ_DEBUG If in doubt, say N. +config ARM_BRCMSTB_CPUFREQ + tristate "Broadcom STB CPUfreq driver" + depends on ARCH_BRCMSTB || COMPILE_TEST + default y + help + Some Broadcom SoCs offer multiple operating frequencies that CPUfreq + can take advantage of to improve energy efficiency. + + Say Y, if you have a supported Broadcom SoC. If your Broadcom SoC + has AVS firmware with support for frequency and voltage scaling, + say N here and enable ARM_BRCMSTB_AVS_CPUFREQ instead. + config ARM_DT_BL_CPUFREQ tristate "Generic probing via DT for ARM big LITTLE CPUfreq driver" depends on ARM_BIG_LITTLE_CPUFREQ && OF diff --git a/drivers/cpufreq/Makefile b/drivers/cpufreq/Makefile index 1e46c39..23700aa 100644 --- a/drivers/cpufreq/Makefile +++ b/drivers/cpufreq/Makefile @@ -52,6 +52,7 @@ obj-$(CONFIG_ARM_BIG_LITTLE_CPUFREQ) += arm_big_little.o obj-$(CONFIG_ARM_DT_BL_CPUFREQ) += arm_big_little_dt.o obj-$(CONFIG_ARM_BRCMSTB_AVS_CPUFREQ) += brcmstb-avs-cpufreq.o +obj-$(CONFIG_ARM_BRCMSTB_CPUFREQ) += brcmstb-cpufreq.o obj-$(CONFIG_ARCH_DAVINCI) += davinci-cpufreq.o obj-$(CONFIG_UX500_SOC_DB8500) += dbx500-cpufreq.o obj-$(CONFIG_ARM_EXYNOS5440_CPUFREQ) += exynos5440-cpufreq.o diff --git a/drivers/cpufreq/brcmstb-cpufreq.c b/drivers/cpufreq/brcmstb-cpufreq.c new file mode 100644 index 0000000..0270789 --- /dev/null +++ b/drivers/cpufreq/brcmstb-cpufreq.c @@ -0,0 +1,381 @@ +/* + * CPU frequency scaling for Broadcom set top box SoCs + * + * Copyright (c) 2016 Broadcom + * + * 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 version 2. + * + * This program is distributed "as is" WITHOUT ANY WARRANTY of any + * kind, whether express or implied; without even the implied warranty + * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + */ + +#include <linux/clk.h> +#include <linux/clk-provider.h> +#include <linux/cpufreq.h> +#include <linux/module.h> +#include <linux/of_address.h> +#include <linux/platform_device.h> + +#define BRCMSTB_CPUFREQ_PREFIX "brcmstb" +#define BRCMSTB_CPUFREQ_NAME BRCMSTB_CPUFREQ_PREFIX "-cpufreq" + +/* We search for these compatible strings. */ +#define BRCMSTB_DT_CPU_CLK_CTRL "brcm,brcmstb-cpu-clk-div" +#define BRCMSTB_DT_MEMC_DDR "brcm,brcmstb-memc-ddr" +#define BRCM_AVS_CPU_DATA "brcm,avs-cpu-data-mem" + +/* We also need a few clocks in device tree. These are node names. */ +#define BRCMSTB_CLK_MDIV_CH0 "cpu_mdiv_ch0" +#define BRCMSTB_CLK_NDIV_INT "cpu_ndiv_int" +#define BRCMSTB_CLK_SW_SCB "sw_scb" + +#define BRCMSTB_TBL_SAFE_MODE BIT(0) +#define BRCMSTB_REG_SAFE_MODE BIT(4) + +#define TRANSITION_LATENCY (25 * 1000) /* 25 us */ + +/* This is as low as we'll go in the frequency table. */ +#define MIN_CPU_FREQ (100 * 1000) /* in kHz */ + +struct private_data { + void __iomem *cpu_clk_ctrl_reg; + struct device *dev; +}; + +/* Count the active memory controllers in the system. */ +static int count_memory_controllers(void) +{ + struct device_node *np = NULL; + int i = 0; + + do { + np = of_find_compatible_node(np, NULL, BRCMSTB_DT_MEMC_DDR); + if (of_device_is_available(np)) + i++; + of_node_put(np); + } while (np); + + return i; +} + +static int get_frequencies(const struct cpufreq_policy *policy, + unsigned int *vco_freq, unsigned int *cpu_freq, + unsigned int *scb_freq) +{ + struct clk *cpu_ndiv_int, *sw_scb; + + cpu_ndiv_int = __clk_lookup(BRCMSTB_CLK_NDIV_INT); + if (!cpu_ndiv_int) + return -ENODEV; + + sw_scb = __clk_lookup(BRCMSTB_CLK_SW_SCB); + if (!sw_scb) + return -ENODEV; + + /* return frequencies in kHz */ + *vco_freq = clk_get_rate(cpu_ndiv_int) / 1000; + *cpu_freq = clk_get_rate(policy->clk) / 1000; + *scb_freq = clk_get_rate(sw_scb) / 1000; + + return 0; +} + +/* + * Safe mode: When set, the CPU's bus unit is being throttled. This is done to + * avoid buffer overflows when the CPU-to-bus-clock ratio is low. + * + * The formula as to what constitutes a low CPU-to-bus-clock ratio takes into + * account the number of memory controllers active in the system and the SCB + * frequency. More memory controllers means safe mode is required starting at + * higher frequencies. + * + * For 1 memory controller, cpu_freq/scb_freq must be greater than or equal to + * 2 to not require safe mode. + * + * For 2 or 3 memory controllers, cpu_freq/scb_freq must be greater than or + * equal 3 to not require safe mode. + */ + +static int freq_requires_safe_mode(unsigned int cpu_freq, unsigned int scb_freq, + int num_memc) +{ + unsigned int safe_ratio; + + switch (num_memc) { + case 1: + safe_ratio = 2; + break; + case 2: + case 3: + safe_ratio = 3; + break; + default: + return -EINVAL; + } + + return ((cpu_freq / scb_freq) < safe_ratio); +} + +static struct cpufreq_frequency_table * +brcmstb_get_freq_table(const struct cpufreq_policy *policy) +{ + unsigned int cpu_freq, vco_freq, scb_freq, mdiv, init_mdiv, f; + struct cpufreq_frequency_table *table; + struct private_data *priv; + int num_memc, ret; + unsigned int i = 0; + + ret = get_frequencies(policy, &vco_freq, &cpu_freq, &scb_freq); + if (ret) + return ERR_PTR(ret); + + priv = policy->driver_data; + num_memc = count_memory_controllers(); + + /* Calculate the initial mdiv value. We'll increment mdiv from here. */ + init_mdiv = vco_freq / cpu_freq; + + /* Count how many frequencies we'll offer. */ + f = cpu_freq; + for (mdiv = init_mdiv; f >= MIN_CPU_FREQ; mdiv++, f = vco_freq / mdiv) { + /* We only want to use "whole" MHz. */ + if ((f % 1000) == 0) + i++; + } + + table = devm_kzalloc(priv->dev, (i + 1) * sizeof(*table), GFP_KERNEL); + if (!table) + return ERR_PTR(-ENOMEM); + + /* Now, fill the table. */ + f = cpu_freq; + i = 0; + for (mdiv = init_mdiv; f >= MIN_CPU_FREQ; mdiv++, f = vco_freq / mdiv) { + if ((f % 1000) == 0) { + table[i].frequency = f; + ret = freq_requires_safe_mode(f, scb_freq, num_memc); + if (ret < 0) + return ERR_PTR(ret); + if (ret > 0) + table[i].driver_data |= BRCMSTB_TBL_SAFE_MODE; + i++; + } + } + table[i].frequency = CPUFREQ_TABLE_END; + + return table; +} + +static int brcmstb_target_index(struct cpufreq_policy *policy, + unsigned int index) +{ + struct cpufreq_frequency_table *entry; + struct private_data *priv; + int ret, safe_mode_needed; + u32 reg; + + priv = policy->driver_data; + entry = &policy->freq_table[index]; + safe_mode_needed = entry->driver_data & BRCMSTB_TBL_SAFE_MODE; + + reg = readl(priv->cpu_clk_ctrl_reg); + if (safe_mode_needed && !(reg & BRCMSTB_REG_SAFE_MODE)) { + reg |= BRCMSTB_REG_SAFE_MODE; + writel(reg, priv->cpu_clk_ctrl_reg); + } + ret = clk_set_rate(policy->clk, entry->frequency * 1000); + if (!ret && !safe_mode_needed && (reg & BRCMSTB_REG_SAFE_MODE)) { + reg &= ~BRCMSTB_REG_SAFE_MODE; + writel(reg, priv->cpu_clk_ctrl_reg); + } + + return ret; +} + +/* + * All initialization code that we only want to execute once goes here. Setup + * code that can be re-tried on every core (if it failed before) can go into + * brcm_avs_cpufreq_init(). + */ +static int brcmstb_prepare_init(struct platform_device *pdev) +{ + struct private_data *priv; + struct resource *res; + struct device *dev; + + /* + * If the BRCM STB AVS CPUfreq driver is supported, we bail, so that + * the more modern approach implementing DVFS in firmware can be used. + */ + if (IS_ENABLED(CONFIG_ARM_BRCM_AVS_CPUFREQ)) { + struct device_node *np; + + np = of_find_compatible_node(NULL, NULL, BRCM_AVS_CPU_DATA); + if (np) { + of_node_put(np); + return -ENXIO; + } + } + + dev = &pdev->dev; + + priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL); + if (!priv) + return -ENOMEM; + + res = platform_get_resource(pdev, IORESOURCE_MEM, 0); + priv->cpu_clk_ctrl_reg = devm_ioremap_resource(dev, res); + if (IS_ERR(priv->cpu_clk_ctrl_reg)) { + dev_err(dev, "couldn't map DT entry %s\n", + BRCMSTB_DT_CPU_CLK_CTRL); + return -ENODEV; + } + + priv->dev = dev; + platform_set_drvdata(pdev, priv); + + return 0; +} + +static int brcmstb_cpu_init(struct cpufreq_policy *policy) +{ + struct cpufreq_frequency_table *freq_table; + struct platform_device *pdev; + struct private_data *priv; + struct clk *cpu_mdiv_ch0; + struct device *dev; + int ret; + + cpu_mdiv_ch0 = __clk_lookup(BRCMSTB_CLK_MDIV_CH0); + if (!cpu_mdiv_ch0) + return -ENODEV; + + pdev = cpufreq_get_driver_data(); + priv = platform_get_drvdata(pdev); + dev = &pdev->dev; + + policy->clk = cpu_mdiv_ch0; + policy->driver_data = priv; + + freq_table = brcmstb_get_freq_table(policy); + if (IS_ERR(freq_table)) { + ret = PTR_ERR(freq_table); + dev_err(dev, "Couldn't determine frequency table (%d).\n", ret); + if (ret == -EINVAL) + dev_emerg(dev, + "Invalid number of memory controllers -- %d!\n", + count_memory_controllers()); + return ret; + } + + ret = cpufreq_generic_init(policy, freq_table, TRANSITION_LATENCY); + if (!ret) + dev_info(dev, "registered\n"); + + return ret; +} + +/* Shows the number of memory controllers. */ +static ssize_t show_brcmstb_num_memc(struct cpufreq_policy *policy, char *buf) +{ + return sprintf(buf, "%u\n", count_memory_controllers()); +} + +/* Shows vco_freq, cpu_freq, and scb_freq in kHz. */ +static ssize_t show_brcmstb_freqs(struct cpufreq_policy *policy, char *buf) +{ + unsigned int vco_freq, cpu_freq, scb_freq; + int ret; + + ret = get_frequencies(policy, &vco_freq, &cpu_freq, &scb_freq); + if (ret) + return sprintf(buf, "<unknown>\n"); + + return sprintf(buf, "%u %u %u\n", vco_freq, cpu_freq, scb_freq); +} + +/* Shows the lowest frequency (in kHz) that can be used without "safe mode". */ +static ssize_t show_brcmstb_safe_freq(struct cpufreq_policy *policy, char *buf) +{ + struct cpufreq_frequency_table *entry; + unsigned int safe_freq = 0; + + cpufreq_for_each_valid_entry(entry, policy->freq_table) { + if (!(entry->driver_data & BRCMSTB_TBL_SAFE_MODE)) + safe_freq = entry->frequency; + } + + return sprintf(buf, "%u\n", safe_freq); +} + +cpufreq_freq_attr_ro(brcmstb_num_memc); +cpufreq_freq_attr_ro(brcmstb_freqs); +cpufreq_freq_attr_ro(brcmstb_safe_freq); + +static struct freq_attr *brcmstb_cpufreq_attr[] = { + &cpufreq_freq_attr_scaling_available_freqs, + &brcmstb_num_memc, + &brcmstb_freqs, + &brcmstb_safe_freq, + NULL +}; + +static struct cpufreq_driver brcmstb_driver = { + .flags = CPUFREQ_NEED_INITIAL_FREQ_CHECK, + .verify = cpufreq_generic_frequency_table_verify, + .target_index = brcmstb_target_index, + .get = cpufreq_generic_get, + .init = brcmstb_cpu_init, + .attr = brcmstb_cpufreq_attr, + .name = BRCMSTB_CPUFREQ_PREFIX, +}; + +static int brcmstb_cpufreq_probe(struct platform_device *pdev) +{ + int ret; + + ret = brcmstb_prepare_init(pdev); + if (ret) + return ret; + + brcmstb_driver.driver_data = pdev; + + return cpufreq_register_driver(&brcmstb_driver); +} + +static int brcmstb_cpufreq_remove(struct platform_device *pdev) +{ + int ret; + + ret = cpufreq_unregister_driver(&brcmstb_driver); + if (ret) + return ret; + + platform_set_drvdata(pdev, NULL); + + return 0; +} + +static const struct of_device_id brcmstb_cpufreq_match[] = { + { .compatible = BRCMSTB_DT_CPU_CLK_CTRL }, + { } +}; +MODULE_DEVICE_TABLE(platform, brcmstb_cpufreq_match); + +static struct platform_driver brcmstb_cpufreq_platdrv = { + .driver = { + .name = BRCMSTB_CPUFREQ_NAME, + .of_match_table = brcmstb_cpufreq_match, + }, + .probe = brcmstb_cpufreq_probe, + .remove = brcmstb_cpufreq_remove, +}; +module_platform_driver(brcmstb_cpufreq_platdrv); + +MODULE_AUTHOR("Markus Mayer <mmayer@broadcom.com>"); +MODULE_DESCRIPTION("CPUfreq driver for Broadcom STB SoCs"); +MODULE_LICENSE("GPL");