Initial import

1 files changed, 194 insertions, 0 deletions

diff --git a/drivers/cpufreq/kirkwood-cpufreq.c b/drivers/cpufreq/kirkwood-cpufreq.c
new file mode 100644
index 000000000..be42f103d
--- /dev/null
+++ b/drivers/cpufreq/kirkwood-cpufreq.c
@@ -0,0 +1,194 @@
+/*
+ *	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/cpufreq.h>
+#include <linux/of_device.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[] = {
+	{0, STATE_CPU_FREQ,	0}, /* CPU uses cpuclk */
+	{0, STATE_DDR_FREQ,	0}, /* CPU uses ddrclk */
+	{0, 0,			CPUFREQ_TABLE_END},
+};
+
+static unsigned int kirkwood_cpufreq_get_cpu_frequency(unsigned int cpu)
+{
+	return clk_get_rate(priv.powersave_clk) / 1000;
+}
+
+static int kirkwood_cpufreq_target(struct cpufreq_policy *policy,
+			    unsigned int index)
+{
+	unsigned int state = kirkwood_freq_table[index].driver_data;
+	unsigned long reg;
+
+	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_set_parent(priv.powersave_clk, priv.cpu_clk);
+		break;
+	case STATE_DDR_FREQ:
+		clk_set_parent(priv.powersave_clk, priv.ddr_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();
+
+	return 0;
+}
+
+/* Module init and exit code */
+static int kirkwood_cpufreq_cpu_init(struct cpufreq_policy *policy)
+{
+	return cpufreq_generic_init(policy, kirkwood_freq_table, 5000);
+}
+
+static struct cpufreq_driver kirkwood_cpufreq_driver = {
+	.flags	= CPUFREQ_NEED_INITIAL_FREQ_CHECK,
+	.get	= kirkwood_cpufreq_get_cpu_frequency,
+	.verify	= cpufreq_generic_frequency_table_verify,
+	.target_index = kirkwood_cpufreq_target,
+	.init	= kirkwood_cpufreq_cpu_init,
+	.name	= "kirkwood-cpufreq",
+	.attr	= cpufreq_generic_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_cpu_device_node_get(0);
+	if (!np) {
+		dev_err(&pdev->dev, "failed to get cpu device node\n");
+		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_enable(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",
+	},
+};
+
+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");