[PATCH v4 1/3] cpufreq: kirkwood: Add a cpufreq driver for Marvell Kirkwood SoCs
Shawn Guo
shawn.guo at linaro.org
Sun Feb 3 09:14:20 EST 2013
On Fri, Feb 01, 2013 at 03:31:33PM +0100, Andrew Lunn wrote:
> The Marvell Kirkwood SoCs have simple cpufreq support in hardware. The
> CPU can either use the a high speed cpu clock, or the slower DDR
> clock. Add a driver to swap between these two clock sources.
>
> Signed-off-by: Andrew Lunn <andrew at lunn.ch>
> Acked-by: Jason Cooper <jason at lakedaemon.net>
> ---
>
> To be commited by: Rafael J. Wysocki
>
> drivers/clk/mvebu/clk-gating-ctrl.c | 1 +
> drivers/cpufreq/Kconfig.arm | 6 +
> drivers/cpufreq/Makefile | 1 +
> drivers/cpufreq/kirkwood-cpufreq.c | 277 +++++++++++++++++++++++++++++++++++
> 4 files changed, 285 insertions(+)
> create mode 100644 drivers/cpufreq/kirkwood-cpufreq.c
>
> diff --git a/drivers/clk/mvebu/clk-gating-ctrl.c b/drivers/clk/mvebu/clk-gating-ctrl.c
> index 8fa5408..ebf141d 100644
> --- a/drivers/clk/mvebu/clk-gating-ctrl.c
> +++ b/drivers/clk/mvebu/clk-gating-ctrl.c
> @@ -193,6 +193,7 @@ static const struct mvebu_soc_descr __initconst kirkwood_gating_descr[] = {
> { "runit", NULL, 7 },
> { "xor0", NULL, 8 },
> { "audio", NULL, 9 },
> + { "powersave", "cpuclk", 11 },
> { "sata0", NULL, 14 },
> { "sata1", NULL, 15 },
> { "xor1", NULL, 16 },
> diff --git a/drivers/cpufreq/Kconfig.arm b/drivers/cpufreq/Kconfig.arm
> index a0b3661..80c8229 100644
> --- a/drivers/cpufreq/Kconfig.arm
> +++ b/drivers/cpufreq/Kconfig.arm
> @@ -77,6 +77,12 @@ config ARM_EXYNOS5250_CPUFREQ
> This adds the CPUFreq driver for Samsung EXYNOS5250
> SoC.
>
> +config ARM_KIRKWOOD_CPUFREQ
> + def_bool ARCH_KIRKWOOD && OF
> + help
> + This adds the CPUFreq driver for Marvell Kirkwood
> + SoCs.
> +
> config ARM_SPEAR_CPUFREQ
> bool "SPEAr CPUFreq support"
> depends on PLAT_SPEAR
> diff --git a/drivers/cpufreq/Makefile b/drivers/cpufreq/Makefile
> index fadc4d4..39a0ffe 100644
> --- a/drivers/cpufreq/Makefile
> +++ b/drivers/cpufreq/Makefile
> @@ -50,6 +50,7 @@ obj-$(CONFIG_ARM_EXYNOS_CPUFREQ) += exynos-cpufreq.o
> obj-$(CONFIG_ARM_EXYNOS4210_CPUFREQ) += exynos4210-cpufreq.o
> obj-$(CONFIG_ARM_EXYNOS4X12_CPUFREQ) += exynos4x12-cpufreq.o
> obj-$(CONFIG_ARM_EXYNOS5250_CPUFREQ) += exynos5250-cpufreq.o
> +obj-$(CONFIG_ARM_KIRKWOOD_CPUFREQ) += kirkwood-cpufreq.o
> obj-$(CONFIG_ARM_OMAP2PLUS_CPUFREQ) += omap-cpufreq.o
> obj-$(CONFIG_ARM_SPEAR_CPUFREQ) += spear-cpufreq.o
>
> diff --git a/drivers/cpufreq/kirkwood-cpufreq.c b/drivers/cpufreq/kirkwood-cpufreq.c
> new file mode 100644
> index 0000000..8923689
> --- /dev/null
> +++ b/drivers/cpufreq/kirkwood-cpufreq.c
> @@ -0,0 +1,277 @@
> +/*
> + * kirkwood_freq.c: cpufreq driver for the Marvell kirkwood
> + *
> + * Copyright (C) 2013 Andrew Lunn <andrew at 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>
Why do you need this header?
> +#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_core = of_find_compatible_node(
> + NULL, NULL, "marvell,kirkwood-core-clock");
> + struct device_node *np_gating = of_find_compatible_node(
> + NULL, NULL, "marvell,kirkwood-gating-clock");
> + struct of_phandle_args clkspec;
> + struct resource *res;
> + int err;
> +
> + if (!np_core || !np_gating) {
> + if (np_core)
> + of_node_put(np_core);
> + if (np_gating)
> + of_node_put(np_gating);
> + return -ENODEV;
> + }
> +
> + priv.dev = &pdev->dev;
> +
> + res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> + if (!res) {
> + dev_err(&pdev->dev, "Cannot get memory resource\n");
> + return -ENODEV;
> + }
> + priv.base = devm_request_and_ioremap(&pdev->dev, res);
> + if (!priv.base) {
> + dev_err(&pdev->dev, "Cannot ioremap\n");
> + return -EADDRNOTAVAIL;
> + }
> +
> + clkspec.np = np_core;
> + clkspec.args_count = 1;
> + clkspec.args[0] = 1;
> +
> + priv.cpu_clk = of_clk_get_from_provider(&clkspec);
Again, clk client is not really supposed to call this. Having a node
in device tree consuming all the clocks you need and attaching the
node to pdev->dev.of_node will have devm_clk_get just work for you.
The node could reasonably be /cpus/cpu at 0.
Shawn
> + 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;
> +
> + clkspec.args[0] = 3;
> + priv.ddr_clk = of_clk_get_from_provider(&clkspec);
> + 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;
> +
> + clkspec.np = np_gating;
> + clkspec.args[0] = 11;
> + priv.powersave_clk = of_clk_get_from_provider(&clkspec);
> + 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_core);
> + np_core = NULL;
> + of_node_put(np_gating);
> + np_gating = 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_core);
> + of_node_put(np_gating);
> +
> + 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 at lunn.ch");
> +MODULE_DESCRIPTION("cpufreq driver for Marvell's kirkwood CPU");
> +MODULE_ALIAS("platform:kirkwood-cpufreq");
> --
> 1.7.10.4
>
>
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