From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751612AbdASAdV (ORCPT ); Wed, 18 Jan 2017 19:33:21 -0500 Received: from smtp-out-no.shaw.ca ([64.59.134.9]:60598 "EHLO smtp-out-no.shaw.ca" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751371AbdASAdT (ORCPT ); Wed, 18 Jan 2017 19:33:19 -0500 X-Authority-Analysis: v=2.2 cv=JLBLi4Cb c=1 sm=1 tr=0 a=6xzog4CasRozao6qlzTIAw==:117 a=6xzog4CasRozao6qlzTIAw==:17 a=IgFoBzBjUZAA:10 a=Q-fNiiVtAAAA:8 a=KKAkSRfTAAAA:8 a=wzpW2ZocSzMn848KLHwA:9 a=1gJoM7IjDHqd-eSW:21 a=HYMzxBUlZLBIRg3_:21 a=Fp8MccfUoT0GBdDC_Lng:22 a=cvBusfyB2V15izCimMoJ:22 From: Markus Mayer To: Michael Turquette , Stephen Boyd , Rob Herring , Mark Rutland , Viresh Kumar , "Rafael J . Wysocki" , Arnd Bergmann Cc: Markus Mayer , Broadcom Kernel List , Linux Clock List , Power Management List , Device Tree List , ARM Kernel List , Linux Kernel Mailing List Subject: [PATCH v5 2/2] cpufreq: brcmstb-cpufreq: CPUfreq driver for older Broadcom STB SoCs Date: Wed, 18 Jan 2017 16:29:33 -0800 Message-Id: <20170119002933.7529-3-code@mmayer.net> X-Mailer: git-send-email 2.10.2 In-Reply-To: <20170119002933.7529-1-code@mmayer.net> References: <20170119002933.7529-1-code@mmayer.net> X-CMAE-Envelope: MS4wfJsHD4SICl2GwOb0cACgP9Moi6DS851R4U29uxNU+5LOTwqUvwOw+6NrQRJdUtJoEF5L3ooO7dSyNgfWMjGNhAwkv9MUbqETkPYq2NbpkUJE0+VLrMbN /TdKoXVpzy/3uIFQFvklEURSRYh+Cm8i7tzhwPPsDOAJr8MyOoo8zoc7vaZIZzKKX7NNcqw6abucoknwtZVyr+VmjzLdxtu74IKybFwY8SulYEVvMCdiQaCk k9Q8MEI8gENg9YLc1oLkw9va4ipML+tNCmJ9Ahi2rYBETmM15WcurCfwUGH1aG2hFoj/OniDvEEqUSP7Y/0NwfaycNpzaUA4IIfa0qgHP61gq3cPzrq/dARH ++z6wyBJSbuFTC2LVj0G7ymmjgfw2aiNPpYSuY4elqQVV9eh8LcEjWAqyOteL+RPDT9tx2auniKMX4oZNlrJXrmFSzYk9X2HbQQp3a3+ZRvqtQBGOTqAEguT 5ZlIuz9hYttv9uAJ3txQgGxDyQYIvr2Cw8lKIeW+GGZlnVsJLkjqJUEgkSRhieIko1R9SZwnmOU0AJxwO8GyOkPaZO1r0O9x5SEr7M1NQRUoBnrsSZZW+qgi w9j8XUnw+zOYCtyisqwT8cg5Jg7VbFqYlDgxNdqRktA0wU26/t68O1Ivu8aQShYb3d8= Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Markus Mayer 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 Acked-by: Viresh Kumar --- drivers/cpufreq/Kconfig.arm | 12 ++ drivers/cpufreq/Makefile | 1 + drivers/cpufreq/brcmstb-cpufreq.c | 377 ++++++++++++++++++++++++++++++++++++++ 3 files changed, 390 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..8849d56 --- /dev/null +++ b/drivers/cpufreq/brcmstb-cpufreq.c @@ -0,0 +1,377 @@ +/* + * CPU frequency scaling for Broadcom set top box SoCs + * + * Copyright (c) 2016-17 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 +#include +#include +#include +#include +#include + +#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. They are referenced in the + * brcm,brcmstb-cpu-clk-div node in device tree, so we can look them up. + */ +#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 clk *mdiv_clk; + struct clk *ndiv_clk; + struct clk *sw_scb_clk; + 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 void get_frequencies(const struct cpufreq_policy *policy, + unsigned int *vco_freq, unsigned int *cpu_freq, + unsigned int *scb_freq) +{ + struct private_data *priv = policy->driver_data; + + /* return frequencies in kHz */ + *vco_freq = clk_get_rate(priv->ndiv_clk) / 1000; + *cpu_freq = clk_get_rate(priv->mdiv_clk) / 1000; + *scb_freq = clk_get_rate(priv->sw_scb_clk) / 1000; +} + +/* + * 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; + + priv = policy->driver_data; + num_memc = count_memory_controllers(); + get_frequencies(policy, &vco_freq, &cpu_freq, &scb_freq); + + /* 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 + * brcmstb_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_BRCMSTB_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->mdiv_clk = devm_clk_get(dev, BRCMSTB_CLK_MDIV_CH0); + priv->ndiv_clk = devm_clk_get(dev, BRCMSTB_CLK_NDIV_INT); + priv->sw_scb_clk = devm_clk_get(dev, BRCMSTB_CLK_SW_SCB); + + if (IS_ERR(priv->mdiv_clk)) + return PTR_ERR(priv->mdiv_clk); + if (IS_ERR(priv->ndiv_clk)) + return PTR_ERR(priv->ndiv_clk); + if (IS_ERR(priv->sw_scb_clk)) + return PTR_ERR(priv->sw_scb_clk); + + priv->dev = dev; + platform_set_drvdata(pdev, priv); + + return 0; +} + +static int brcmstb_cpufreq_init(struct cpufreq_policy *policy) +{ + struct cpufreq_frequency_table *freq_table; + struct platform_device *pdev; + struct private_data *priv; + struct device *dev; + int ret; + + pdev = cpufreq_get_driver_data(); + priv = platform_get_drvdata(pdev); + dev = &pdev->dev; + + policy->clk = priv->mdiv_clk; + 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; + + get_frequencies(policy, &vco_freq, &cpu_freq, &scb_freq); + + 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_cpufreq_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(of, 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 "); +MODULE_DESCRIPTION("CPUfreq driver for Broadcom STB SoCs"); +MODULE_LICENSE("GPL"); -- 2.7.4