| /* |
| * kirkwood_freq.c: cpufreq driver for the Marvell kirkwood |
| * |
| * Copyright (C) 2013 Andrew Lunn <andrew@lunn.ch> |
| * |
| * 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; either version |
| * 2 of the License, or (at your option) any later version. |
| */ |
| |
| #include <linux/kernel.h> |
| #include <linux/module.h> |
| #include <linux/clk.h> |
| #include <linux/clk-provider.h> |
| #include <linux/cpufreq.h> |
| #include <linux/of.h> |
| #include <linux/platform_device.h> |
| #include <linux/io.h> |
| #include <asm/proc-fns.h> |
| |
| #define CPU_SW_INT_BLK BIT(28) |
| |
| static struct priv |
| { |
| struct clk *cpu_clk; |
| struct clk *ddr_clk; |
| struct clk *powersave_clk; |
| struct device *dev; |
| void __iomem *base; |
| } priv; |
| |
| #define STATE_CPU_FREQ 0x01 |
| #define STATE_DDR_FREQ 0x02 |
| |
| /* |
| * Kirkwood can swap the clock to the CPU between two clocks: |
| * |
| * - cpu clk |
| * - ddr clk |
| * |
| * The frequencies are set at runtime before registering this * |
| * table. |
| */ |
| static struct cpufreq_frequency_table kirkwood_freq_table[] = { |
| {STATE_CPU_FREQ, 0}, /* CPU uses cpuclk */ |
| {STATE_DDR_FREQ, 0}, /* CPU uses ddrclk */ |
| {0, CPUFREQ_TABLE_END}, |
| }; |
| |
| static unsigned int kirkwood_cpufreq_get_cpu_frequency(unsigned int cpu) |
| { |
| if (__clk_is_enabled(priv.powersave_clk)) |
| return kirkwood_freq_table[1].frequency; |
| return kirkwood_freq_table[0].frequency; |
| } |
| |
| static void kirkwood_cpufreq_set_cpu_state(unsigned int index) |
| { |
| struct cpufreq_freqs freqs; |
| unsigned int state = kirkwood_freq_table[index].index; |
| unsigned long reg; |
| |
| freqs.old = kirkwood_cpufreq_get_cpu_frequency(0); |
| freqs.new = kirkwood_freq_table[index].frequency; |
| freqs.cpu = 0; /* Kirkwood is UP */ |
| |
| cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE); |
| |
| dev_dbg(priv.dev, "Attempting to set frequency to %i KHz\n", |
| kirkwood_freq_table[index].frequency); |
| dev_dbg(priv.dev, "old frequency was %i KHz\n", |
| kirkwood_cpufreq_get_cpu_frequency(0)); |
| |
| if (freqs.old != freqs.new) { |
| local_irq_disable(); |
| |
| /* Disable interrupts to the CPU */ |
| reg = readl_relaxed(priv.base); |
| reg |= CPU_SW_INT_BLK; |
| writel_relaxed(reg, priv.base); |
| |
| switch (state) { |
| case STATE_CPU_FREQ: |
| clk_disable(priv.powersave_clk); |
| break; |
| case STATE_DDR_FREQ: |
| clk_enable(priv.powersave_clk); |
| break; |
| } |
| |
| /* Wait-for-Interrupt, while the hardware changes frequency */ |
| cpu_do_idle(); |
| |
| /* Enable interrupts to the CPU */ |
| reg = readl_relaxed(priv.base); |
| reg &= ~CPU_SW_INT_BLK; |
| writel_relaxed(reg, priv.base); |
| |
| local_irq_enable(); |
| } |
| cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE); |
| }; |
| |
| static int kirkwood_cpufreq_verify(struct cpufreq_policy *policy) |
| { |
| return cpufreq_frequency_table_verify(policy, kirkwood_freq_table); |
| } |
| |
| static int kirkwood_cpufreq_target(struct cpufreq_policy *policy, |
| unsigned int target_freq, |
| unsigned int relation) |
| { |
| unsigned int index = 0; |
| |
| if (cpufreq_frequency_table_target(policy, kirkwood_freq_table, |
| target_freq, relation, &index)) |
| return -EINVAL; |
| |
| kirkwood_cpufreq_set_cpu_state(index); |
| |
| return 0; |
| } |
| |
| /* Module init and exit code */ |
| static int kirkwood_cpufreq_cpu_init(struct cpufreq_policy *policy) |
| { |
| int result; |
| |
| /* cpuinfo and default policy values */ |
| policy->cpuinfo.transition_latency = 5000; /* 5uS */ |
| policy->cur = kirkwood_cpufreq_get_cpu_frequency(0); |
| |
| result = cpufreq_frequency_table_cpuinfo(policy, kirkwood_freq_table); |
| if (result) |
| return result; |
| |
| cpufreq_frequency_table_get_attr(kirkwood_freq_table, policy->cpu); |
| |
| return 0; |
| } |
| |
| static int kirkwood_cpufreq_cpu_exit(struct cpufreq_policy *policy) |
| { |
| cpufreq_frequency_table_put_attr(policy->cpu); |
| return 0; |
| } |
| |
| static struct freq_attr *kirkwood_cpufreq_attr[] = { |
| &cpufreq_freq_attr_scaling_available_freqs, |
| NULL, |
| }; |
| |
| static struct cpufreq_driver kirkwood_cpufreq_driver = { |
| .get = kirkwood_cpufreq_get_cpu_frequency, |
| .verify = kirkwood_cpufreq_verify, |
| .target = kirkwood_cpufreq_target, |
| .init = kirkwood_cpufreq_cpu_init, |
| .exit = kirkwood_cpufreq_cpu_exit, |
| .name = "kirkwood-cpufreq", |
| .owner = THIS_MODULE, |
| .attr = kirkwood_cpufreq_attr, |
| }; |
| |
| static int kirkwood_cpufreq_probe(struct platform_device *pdev) |
| { |
| struct device_node *np; |
| struct resource *res; |
| int err; |
| |
| priv.dev = &pdev->dev; |
| |
| res = platform_get_resource(pdev, IORESOURCE_MEM, 0); |
| priv.base = devm_ioremap_resource(&pdev->dev, res); |
| if (IS_ERR(priv.base)) |
| return PTR_ERR(priv.base); |
| |
| np = of_find_node_by_path("/cpus/cpu@0"); |
| if (!np) |
| return -ENODEV; |
| |
| priv.cpu_clk = of_clk_get_by_name(np, "cpu_clk"); |
| if (IS_ERR(priv.cpu_clk)) { |
| dev_err(priv.dev, "Unable to get cpuclk"); |
| return PTR_ERR(priv.cpu_clk); |
| } |
| |
| clk_prepare_enable(priv.cpu_clk); |
| kirkwood_freq_table[0].frequency = clk_get_rate(priv.cpu_clk) / 1000; |
| |
| priv.ddr_clk = of_clk_get_by_name(np, "ddrclk"); |
| if (IS_ERR(priv.ddr_clk)) { |
| dev_err(priv.dev, "Unable to get ddrclk"); |
| err = PTR_ERR(priv.ddr_clk); |
| goto out_cpu; |
| } |
| |
| clk_prepare_enable(priv.ddr_clk); |
| kirkwood_freq_table[1].frequency = clk_get_rate(priv.ddr_clk) / 1000; |
| |
| priv.powersave_clk = of_clk_get_by_name(np, "powersave"); |
| if (IS_ERR(priv.powersave_clk)) { |
| dev_err(priv.dev, "Unable to get powersave"); |
| err = PTR_ERR(priv.powersave_clk); |
| goto out_ddr; |
| } |
| clk_prepare(priv.powersave_clk); |
| |
| of_node_put(np); |
| np = NULL; |
| |
| err = cpufreq_register_driver(&kirkwood_cpufreq_driver); |
| if (!err) |
| return 0; |
| |
| dev_err(priv.dev, "Failed to register cpufreq driver"); |
| |
| clk_disable_unprepare(priv.powersave_clk); |
| out_ddr: |
| clk_disable_unprepare(priv.ddr_clk); |
| out_cpu: |
| clk_disable_unprepare(priv.cpu_clk); |
| of_node_put(np); |
| |
| return err; |
| } |
| |
| static int kirkwood_cpufreq_remove(struct platform_device *pdev) |
| { |
| cpufreq_unregister_driver(&kirkwood_cpufreq_driver); |
| |
| clk_disable_unprepare(priv.powersave_clk); |
| clk_disable_unprepare(priv.ddr_clk); |
| clk_disable_unprepare(priv.cpu_clk); |
| |
| return 0; |
| } |
| |
| static struct platform_driver kirkwood_cpufreq_platform_driver = { |
| .probe = kirkwood_cpufreq_probe, |
| .remove = kirkwood_cpufreq_remove, |
| .driver = { |
| .name = "kirkwood-cpufreq", |
| .owner = THIS_MODULE, |
| }, |
| }; |
| |
| module_platform_driver(kirkwood_cpufreq_platform_driver); |
| |
| MODULE_LICENSE("GPL v2"); |
| MODULE_AUTHOR("Andrew Lunn <andrew@lunn.ch"); |
| MODULE_DESCRIPTION("cpufreq driver for Marvell's kirkwood CPU"); |
| MODULE_ALIAS("platform:kirkwood-cpufreq"); |