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1// SPDX-License-Identifier: GPL-2.0-or-later2/*3 * kirkwood_freq.c: cpufreq driver for the Marvell kirkwood4 *5 * Copyright (C) 2013 Andrew Lunn <andrew@lunn.ch>6 */7 8#include <linux/kernel.h>9#include <linux/module.h>10#include <linux/clk.h>11#include <linux/cpufreq.h>12#include <linux/of.h>13#include <linux/platform_device.h>14#include <linux/io.h>15#include <asm/proc-fns.h>16 17#define CPU_SW_INT_BLK BIT(28)18 19static struct priv20{21 struct clk *cpu_clk;22 struct clk *ddr_clk;23 struct clk *powersave_clk;24 struct device *dev;25 void __iomem *base;26} priv;27 28#define STATE_CPU_FREQ 0x0129#define STATE_DDR_FREQ 0x0230 31/*32 * Kirkwood can swap the clock to the CPU between two clocks:33 *34 * - cpu clk35 * - ddr clk36 *37 * The frequencies are set at runtime before registering this table.38 */39static struct cpufreq_frequency_table kirkwood_freq_table[] = {40 {0, STATE_CPU_FREQ, 0}, /* CPU uses cpuclk */41 {0, STATE_DDR_FREQ, 0}, /* CPU uses ddrclk */42 {0, 0, CPUFREQ_TABLE_END},43};44 45static unsigned int kirkwood_cpufreq_get_cpu_frequency(unsigned int cpu)46{47 return clk_get_rate(priv.powersave_clk) / 1000;48}49 50static int kirkwood_cpufreq_target(struct cpufreq_policy *policy,51 unsigned int index)52{53 unsigned int state = kirkwood_freq_table[index].driver_data;54 unsigned long reg;55 56 local_irq_disable();57 58 /* Disable interrupts to the CPU */59 reg = readl_relaxed(priv.base);60 reg |= CPU_SW_INT_BLK;61 writel_relaxed(reg, priv.base);62 63 switch (state) {64 case STATE_CPU_FREQ:65 clk_set_parent(priv.powersave_clk, priv.cpu_clk);66 break;67 case STATE_DDR_FREQ:68 clk_set_parent(priv.powersave_clk, priv.ddr_clk);69 break;70 }71 72 /* Wait-for-Interrupt, while the hardware changes frequency */73 cpu_do_idle();74 75 /* Enable interrupts to the CPU */76 reg = readl_relaxed(priv.base);77 reg &= ~CPU_SW_INT_BLK;78 writel_relaxed(reg, priv.base);79 80 local_irq_enable();81 82 return 0;83}84 85/* Module init and exit code */86static int kirkwood_cpufreq_cpu_init(struct cpufreq_policy *policy)87{88 cpufreq_generic_init(policy, kirkwood_freq_table, 5000);89 return 0;90}91 92static struct cpufreq_driver kirkwood_cpufreq_driver = {93 .flags = CPUFREQ_NEED_INITIAL_FREQ_CHECK,94 .get = kirkwood_cpufreq_get_cpu_frequency,95 .verify = cpufreq_generic_frequency_table_verify,96 .target_index = kirkwood_cpufreq_target,97 .init = kirkwood_cpufreq_cpu_init,98 .name = "kirkwood-cpufreq",99 .attr = cpufreq_generic_attr,100};101 102static int kirkwood_cpufreq_probe(struct platform_device *pdev)103{104 struct device_node *np;105 int err;106 107 priv.dev = &pdev->dev;108 109 priv.base = devm_platform_ioremap_resource(pdev, 0);110 if (IS_ERR(priv.base))111 return PTR_ERR(priv.base);112 113 np = of_cpu_device_node_get(0);114 if (!np) {115 dev_err(&pdev->dev, "failed to get cpu device node\n");116 return -ENODEV;117 }118 119 priv.cpu_clk = of_clk_get_by_name(np, "cpu_clk");120 if (IS_ERR(priv.cpu_clk)) {121 dev_err(priv.dev, "Unable to get cpuclk\n");122 err = PTR_ERR(priv.cpu_clk);123 goto out_node;124 }125 126 err = clk_prepare_enable(priv.cpu_clk);127 if (err) {128 dev_err(priv.dev, "Unable to prepare cpuclk\n");129 goto out_node;130 }131 132 kirkwood_freq_table[0].frequency = clk_get_rate(priv.cpu_clk) / 1000;133 134 priv.ddr_clk = of_clk_get_by_name(np, "ddrclk");135 if (IS_ERR(priv.ddr_clk)) {136 dev_err(priv.dev, "Unable to get ddrclk\n");137 err = PTR_ERR(priv.ddr_clk);138 goto out_cpu;139 }140 141 err = clk_prepare_enable(priv.ddr_clk);142 if (err) {143 dev_err(priv.dev, "Unable to prepare ddrclk\n");144 goto out_cpu;145 }146 kirkwood_freq_table[1].frequency = clk_get_rate(priv.ddr_clk) / 1000;147 148 priv.powersave_clk = of_clk_get_by_name(np, "powersave");149 if (IS_ERR(priv.powersave_clk)) {150 dev_err(priv.dev, "Unable to get powersave\n");151 err = PTR_ERR(priv.powersave_clk);152 goto out_ddr;153 }154 err = clk_prepare_enable(priv.powersave_clk);155 if (err) {156 dev_err(priv.dev, "Unable to prepare powersave clk\n");157 goto out_ddr;158 }159 160 err = cpufreq_register_driver(&kirkwood_cpufreq_driver);161 if (err) {162 dev_err(priv.dev, "Failed to register cpufreq driver\n");163 goto out_powersave;164 }165 166 of_node_put(np);167 return 0;168 169out_powersave:170 clk_disable_unprepare(priv.powersave_clk);171out_ddr:172 clk_disable_unprepare(priv.ddr_clk);173out_cpu:174 clk_disable_unprepare(priv.cpu_clk);175out_node:176 of_node_put(np);177 178 return err;179}180 181static void kirkwood_cpufreq_remove(struct platform_device *pdev)182{183 cpufreq_unregister_driver(&kirkwood_cpufreq_driver);184 185 clk_disable_unprepare(priv.powersave_clk);186 clk_disable_unprepare(priv.ddr_clk);187 clk_disable_unprepare(priv.cpu_clk);188}189 190static struct platform_driver kirkwood_cpufreq_platform_driver = {191 .probe = kirkwood_cpufreq_probe,192 .remove_new = kirkwood_cpufreq_remove,193 .driver = {194 .name = "kirkwood-cpufreq",195 },196};197 198module_platform_driver(kirkwood_cpufreq_platform_driver);199 200MODULE_LICENSE("GPL v2");201MODULE_AUTHOR("Andrew Lunn <andrew@lunn.ch");202MODULE_DESCRIPTION("cpufreq driver for Marvell's kirkwood CPU");203MODULE_ALIAS("platform:kirkwood-cpufreq");204