1 files changed, 222 insertions, 0 deletions

diff --git a/drivers/cpufreq/loongson1-cpufreq.c b/drivers/cpufreq/loongson1-cpufreq.c
new file mode 100644
index 000000000000..be89416e2358
--- /dev/null
+++ b/drivers/cpufreq/loongson1-cpufreq.c
@@ -0,0 +1,222 @@
+/*
+ * CPU Frequency Scaling for Loongson 1 SoC
+ *
+ * Copyright (C) 2014-2016 Zhang, Keguang <keguang.zhang@gmail.com>
+ *
+ * This file is licensed under the terms of the GNU General Public
+ * License version 2. This program is licensed "as is" without any
+ * warranty of any kind, whether express or implied.
+ */
+
+#include <linux/clk.h>
+#include <linux/clk-provider.h>
+#include <linux/cpu.h>
+#include <linux/cpufreq.h>
+#include <linux/delay.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/slab.h>
+
+#include <cpufreq.h>
+#include <loongson1.h>
+
+struct ls1x_cpufreq {
+	struct device *dev;
+	struct clk *clk;	/* CPU clk */
+	struct clk *mux_clk;	/* MUX of CPU clk */
+	struct clk *pll_clk;	/* PLL clk */
+	struct clk *osc_clk;	/* OSC clk */
+	unsigned int max_freq;
+	unsigned int min_freq;
+};
+
+static struct ls1x_cpufreq *cpufreq;
+
+static int ls1x_cpufreq_notifier(struct notifier_block *nb,
+				 unsigned long val, void *data)
+{
+	if (val == CPUFREQ_POSTCHANGE)
+		current_cpu_data.udelay_val = loops_per_jiffy;
+
+	return NOTIFY_OK;
+}
+
+static struct notifier_block ls1x_cpufreq_notifier_block = {
+	.notifier_call = ls1x_cpufreq_notifier
+};
+
+static int ls1x_cpufreq_target(struct cpufreq_policy *policy,
+			       unsigned int index)
+{
+	struct device *cpu_dev = get_cpu_device(policy->cpu);
+	unsigned int old_freq, new_freq;
+
+	old_freq = policy->cur;
+	new_freq = policy->freq_table[index].frequency;
+
+	/*
+	 * The procedure of reconfiguring CPU clk is as below.
+	 *
+	 *  - Reparent CPU clk to OSC clk
+	 *  - Reset CPU clock (very important)
+	 *  - Reconfigure CPU DIV
+	 *  - Reparent CPU clk back to CPU DIV clk
+	 */
+
+	clk_set_parent(policy->clk, cpufreq->osc_clk);
+	__raw_writel(__raw_readl(LS1X_CLK_PLL_DIV) | RST_CPU_EN | RST_CPU,
+		     LS1X_CLK_PLL_DIV);
+	__raw_writel(__raw_readl(LS1X_CLK_PLL_DIV) & ~(RST_CPU_EN | RST_CPU),
+		     LS1X_CLK_PLL_DIV);
+	clk_set_rate(cpufreq->mux_clk, new_freq * 1000);
+	clk_set_parent(policy->clk, cpufreq->mux_clk);
+	dev_dbg(cpu_dev, "%u KHz --> %u KHz\n", old_freq, new_freq);
+
+	return 0;
+}
+
+static int ls1x_cpufreq_init(struct cpufreq_policy *policy)
+{
+	struct device *cpu_dev = get_cpu_device(policy->cpu);
+	struct cpufreq_frequency_table *freq_tbl;
+	unsigned int pll_freq, freq;
+	int steps, i, ret;
+
+	pll_freq = clk_get_rate(cpufreq->pll_clk) / 1000;
+
+	steps = 1 << DIV_CPU_WIDTH;
+	freq_tbl = kcalloc(steps, sizeof(*freq_tbl), GFP_KERNEL);
+	if (!freq_tbl)
+		return -ENOMEM;
+
+	for (i = 0; i < (steps - 1); i++) {
+		freq = pll_freq / (i + 1);
+		if ((freq < cpufreq->min_freq) || (freq > cpufreq->max_freq))
+			freq_tbl[i].frequency = CPUFREQ_ENTRY_INVALID;
+		else
+			freq_tbl[i].frequency = freq;
+		dev_dbg(cpu_dev,
+			"cpufreq table: index %d: frequency %d\n", i,
+			freq_tbl[i].frequency);
+	}
+	freq_tbl[i].frequency = CPUFREQ_TABLE_END;
+
+	policy->clk = cpufreq->clk;
+	ret = cpufreq_generic_init(policy, freq_tbl, 0);
+	if (ret)
+		kfree(freq_tbl);
+
+	return ret;
+}
+
+static int ls1x_cpufreq_exit(struct cpufreq_policy *policy)
+{
+	kfree(policy->freq_table);
+	return 0;
+}
+
+static struct cpufreq_driver ls1x_cpufreq_driver = {
+	.name		= "cpufreq-ls1x",
+	.flags		= CPUFREQ_STICKY | CPUFREQ_NEED_INITIAL_FREQ_CHECK,
+	.verify		= cpufreq_generic_frequency_table_verify,
+	.target_index	= ls1x_cpufreq_target,
+	.get		= cpufreq_generic_get,
+	.init		= ls1x_cpufreq_init,
+	.exit		= ls1x_cpufreq_exit,
+	.attr		= cpufreq_generic_attr,
+};
+
+static int ls1x_cpufreq_remove(struct platform_device *pdev)
+{
+	cpufreq_unregister_notifier(&ls1x_cpufreq_notifier_block,
+				    CPUFREQ_TRANSITION_NOTIFIER);
+	cpufreq_unregister_driver(&ls1x_cpufreq_driver);
+
+	return 0;
+}
+
+static int ls1x_cpufreq_probe(struct platform_device *pdev)
+{
+	struct plat_ls1x_cpufreq *pdata = dev_get_platdata(&pdev->dev);
+	struct clk *clk;
+	int ret;
+
+	if (!pdata || !pdata->clk_name || !pdata->osc_clk_name) {
+		dev_err(&pdev->dev, "platform data missing\n");
+		return -EINVAL;
+	}
+
+	cpufreq =
+	    devm_kzalloc(&pdev->dev, sizeof(struct ls1x_cpufreq), GFP_KERNEL);
+	if (!cpufreq)
+		return -ENOMEM;
+
+	cpufreq->dev = &pdev->dev;
+
+	clk = devm_clk_get(&pdev->dev, pdata->clk_name);
+	if (IS_ERR(clk)) {
+		dev_err(&pdev->dev, "unable to get %s clock\n",
+			pdata->clk_name);
+		return PTR_ERR(clk);
+	}
+	cpufreq->clk = clk;
+
+	clk = clk_get_parent(clk);
+	if (IS_ERR(clk)) {
+		dev_err(&pdev->dev, "unable to get parent of %s clock\n",
+			__clk_get_name(cpufreq->clk));
+		return PTR_ERR(clk);
+	}
+	cpufreq->mux_clk = clk;
+
+	clk = clk_get_parent(clk);
+	if (IS_ERR(clk)) {
+		dev_err(&pdev->dev, "unable to get parent of %s clock\n",
+			__clk_get_name(cpufreq->mux_clk));
+		return PTR_ERR(clk);
+	}
+	cpufreq->pll_clk = clk;
+
+	clk = devm_clk_get(&pdev->dev, pdata->osc_clk_name);
+	if (IS_ERR(clk)) {
+		dev_err(&pdev->dev, "unable to get %s clock\n",
+			pdata->osc_clk_name);
+		return PTR_ERR(clk);
+	}
+	cpufreq->osc_clk = clk;
+
+	cpufreq->max_freq = pdata->max_freq;
+	cpufreq->min_freq = pdata->min_freq;
+
+	ret = cpufreq_register_driver(&ls1x_cpufreq_driver);
+	if (ret) {
+		dev_err(&pdev->dev,
+			"failed to register CPUFreq driver: %d\n", ret);
+		return ret;
+	}
+
+	ret = cpufreq_register_notifier(&ls1x_cpufreq_notifier_block,
+					CPUFREQ_TRANSITION_NOTIFIER);
+
+	if (ret) {
+		dev_err(&pdev->dev,
+			"failed to register CPUFreq notifier: %d\n",ret);
+		cpufreq_unregister_driver(&ls1x_cpufreq_driver);
+	}
+
+	return ret;
+}
+
+static struct platform_driver ls1x_cpufreq_platdrv = {
+	.probe	= ls1x_cpufreq_probe,
+	.remove	= ls1x_cpufreq_remove,
+	.driver	= {
+		.name	= "ls1x-cpufreq",
+	},
+};
+
+module_platform_driver(ls1x_cpufreq_platdrv);
+
+MODULE_AUTHOR("Kelvin Cheung <keguang.zhang@gmail.com>");
+MODULE_DESCRIPTION("Loongson1 CPUFreq driver");
+MODULE_LICENSE("GPL");