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205 lines
4.8 KiB
205 lines
4.8 KiB
// SPDX-License-Identifier: GPL-2.0-or-later |
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/* |
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* kirkwood_freq.c: cpufreq driver for the Marvell kirkwood |
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* |
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* Copyright (C) 2013 Andrew Lunn <[email protected]> |
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*/ |
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#include <linux/kernel.h> |
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#include <linux/module.h> |
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#include <linux/clk.h> |
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#include <linux/cpufreq.h> |
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#include <linux/of_device.h> |
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#include <linux/platform_device.h> |
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#include <linux/io.h> |
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#include <asm/proc-fns.h> |
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#define CPU_SW_INT_BLK BIT(28) |
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static struct priv |
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{ |
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struct clk *cpu_clk; |
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struct clk *ddr_clk; |
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struct clk *powersave_clk; |
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struct device *dev; |
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void __iomem *base; |
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} priv; |
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#define STATE_CPU_FREQ 0x01 |
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#define STATE_DDR_FREQ 0x02 |
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/* |
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* Kirkwood can swap the clock to the CPU between two clocks: |
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* |
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* - cpu clk |
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* - ddr clk |
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* |
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* The frequencies are set at runtime before registering this table. |
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*/ |
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static struct cpufreq_frequency_table kirkwood_freq_table[] = { |
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{0, STATE_CPU_FREQ, 0}, /* CPU uses cpuclk */ |
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{0, STATE_DDR_FREQ, 0}, /* CPU uses ddrclk */ |
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{0, 0, CPUFREQ_TABLE_END}, |
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}; |
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static unsigned int kirkwood_cpufreq_get_cpu_frequency(unsigned int cpu) |
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{ |
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return clk_get_rate(priv.powersave_clk) / 1000; |
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} |
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static int kirkwood_cpufreq_target(struct cpufreq_policy *policy, |
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unsigned int index) |
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{ |
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unsigned int state = kirkwood_freq_table[index].driver_data; |
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unsigned long reg; |
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local_irq_disable(); |
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/* Disable interrupts to the CPU */ |
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reg = readl_relaxed(priv.base); |
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reg |= CPU_SW_INT_BLK; |
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writel_relaxed(reg, priv.base); |
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switch (state) { |
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case STATE_CPU_FREQ: |
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clk_set_parent(priv.powersave_clk, priv.cpu_clk); |
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break; |
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case STATE_DDR_FREQ: |
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clk_set_parent(priv.powersave_clk, priv.ddr_clk); |
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break; |
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} |
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/* Wait-for-Interrupt, while the hardware changes frequency */ |
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cpu_do_idle(); |
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/* Enable interrupts to the CPU */ |
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reg = readl_relaxed(priv.base); |
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reg &= ~CPU_SW_INT_BLK; |
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writel_relaxed(reg, priv.base); |
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local_irq_enable(); |
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return 0; |
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} |
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/* Module init and exit code */ |
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static int kirkwood_cpufreq_cpu_init(struct cpufreq_policy *policy) |
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{ |
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cpufreq_generic_init(policy, kirkwood_freq_table, 5000); |
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return 0; |
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} |
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static struct cpufreq_driver kirkwood_cpufreq_driver = { |
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.flags = CPUFREQ_NEED_INITIAL_FREQ_CHECK, |
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.get = kirkwood_cpufreq_get_cpu_frequency, |
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.verify = cpufreq_generic_frequency_table_verify, |
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.target_index = kirkwood_cpufreq_target, |
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.init = kirkwood_cpufreq_cpu_init, |
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.name = "kirkwood-cpufreq", |
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.attr = cpufreq_generic_attr, |
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}; |
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static int kirkwood_cpufreq_probe(struct platform_device *pdev) |
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{ |
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struct device_node *np; |
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int err; |
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priv.dev = &pdev->dev; |
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priv.base = devm_platform_ioremap_resource(pdev, 0); |
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if (IS_ERR(priv.base)) |
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return PTR_ERR(priv.base); |
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np = of_cpu_device_node_get(0); |
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if (!np) { |
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dev_err(&pdev->dev, "failed to get cpu device node\n"); |
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return -ENODEV; |
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} |
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priv.cpu_clk = of_clk_get_by_name(np, "cpu_clk"); |
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if (IS_ERR(priv.cpu_clk)) { |
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dev_err(priv.dev, "Unable to get cpuclk\n"); |
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err = PTR_ERR(priv.cpu_clk); |
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goto out_node; |
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} |
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err = clk_prepare_enable(priv.cpu_clk); |
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if (err) { |
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dev_err(priv.dev, "Unable to prepare cpuclk\n"); |
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goto out_node; |
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} |
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kirkwood_freq_table[0].frequency = clk_get_rate(priv.cpu_clk) / 1000; |
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priv.ddr_clk = of_clk_get_by_name(np, "ddrclk"); |
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if (IS_ERR(priv.ddr_clk)) { |
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dev_err(priv.dev, "Unable to get ddrclk\n"); |
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err = PTR_ERR(priv.ddr_clk); |
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goto out_cpu; |
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} |
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err = clk_prepare_enable(priv.ddr_clk); |
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if (err) { |
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dev_err(priv.dev, "Unable to prepare ddrclk\n"); |
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goto out_cpu; |
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} |
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kirkwood_freq_table[1].frequency = clk_get_rate(priv.ddr_clk) / 1000; |
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priv.powersave_clk = of_clk_get_by_name(np, "powersave"); |
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if (IS_ERR(priv.powersave_clk)) { |
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dev_err(priv.dev, "Unable to get powersave\n"); |
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err = PTR_ERR(priv.powersave_clk); |
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goto out_ddr; |
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} |
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err = clk_prepare_enable(priv.powersave_clk); |
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if (err) { |
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dev_err(priv.dev, "Unable to prepare powersave clk\n"); |
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goto out_ddr; |
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} |
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err = cpufreq_register_driver(&kirkwood_cpufreq_driver); |
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if (err) { |
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dev_err(priv.dev, "Failed to register cpufreq driver\n"); |
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goto out_powersave; |
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} |
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of_node_put(np); |
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return 0; |
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out_powersave: |
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clk_disable_unprepare(priv.powersave_clk); |
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out_ddr: |
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clk_disable_unprepare(priv.ddr_clk); |
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out_cpu: |
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clk_disable_unprepare(priv.cpu_clk); |
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out_node: |
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of_node_put(np); |
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return err; |
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} |
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static int kirkwood_cpufreq_remove(struct platform_device *pdev) |
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{ |
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cpufreq_unregister_driver(&kirkwood_cpufreq_driver); |
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clk_disable_unprepare(priv.powersave_clk); |
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clk_disable_unprepare(priv.ddr_clk); |
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clk_disable_unprepare(priv.cpu_clk); |
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return 0; |
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} |
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static struct platform_driver kirkwood_cpufreq_platform_driver = { |
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.probe = kirkwood_cpufreq_probe, |
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.remove = kirkwood_cpufreq_remove, |
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.driver = { |
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.name = "kirkwood-cpufreq", |
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}, |
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}; |
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module_platform_driver(kirkwood_cpufreq_platform_driver); |
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MODULE_LICENSE("GPL v2"); |
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MODULE_AUTHOR("Andrew Lunn <[email protected]"); |
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MODULE_DESCRIPTION("cpufreq driver for Marvell's kirkwood CPU"); |
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MODULE_ALIAS("platform:kirkwood-cpufreq");
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