1 files changed, 325 insertions, 0 deletions
diff --git a/drivers/clk/clk-scpi.c b/drivers/clk/clk-scpi.c
new file mode 100644
index 000000000..258547228
--- /dev/null
+++ b/drivers/clk/clk-scpi.c
@@ -0,0 +1,325 @@
+/*
+ * System Control and Power Interface (SCPI) Protocol based clock driver
+ *
+ * Copyright (C) 2015 ARM Ltd.
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
+ * more details.
+ *
+ * You should have received a copy of the GNU General Public License along with
+ * this program. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <linux/clk-provider.h>
+#include <linux/device.h>
+#include <linux/err.h>
+#include <linux/of.h>
+#include <linux/module.h>
+#include <linux/of_platform.h>
+#include <linux/platform_device.h>
+#include <linux/scpi_protocol.h>
+
+struct scpi_clk {
+	u32 id;
+	struct clk_hw hw;
+	struct scpi_dvfs_info *info;
+	struct scpi_ops *scpi_ops;
+};
+
+#define to_scpi_clk(clk) container_of(clk, struct scpi_clk, hw)
+
+static struct platform_device *cpufreq_dev;
+
+static unsigned long scpi_clk_recalc_rate(struct clk_hw *hw,
+					  unsigned long parent_rate)
+{
+	struct scpi_clk *clk = to_scpi_clk(hw);
+
+	return clk->scpi_ops->clk_get_val(clk->id);
+}
+
+static long scpi_clk_round_rate(struct clk_hw *hw, unsigned long rate,
+				unsigned long *parent_rate)
+{
+	/*
+	 * We can't figure out what rate it will be, so just return the
+	 * rate back to the caller. scpi_clk_recalc_rate() will be called
+	 * after the rate is set and we'll know what rate the clock is
+	 * running at then.
+	 */
+	return rate;
+}
+
+static int scpi_clk_set_rate(struct clk_hw *hw, unsigned long rate,
+			     unsigned long parent_rate)
+{
+	struct scpi_clk *clk = to_scpi_clk(hw);
+
+	return clk->scpi_ops->clk_set_val(clk->id, rate);
+}
+
+static const struct clk_ops scpi_clk_ops = {
+	.recalc_rate = scpi_clk_recalc_rate,
+	.round_rate = scpi_clk_round_rate,
+	.set_rate = scpi_clk_set_rate,
+};
+
+/* find closest match to given frequency in OPP table */
+static long __scpi_dvfs_round_rate(struct scpi_clk *clk, unsigned long rate)
+{
+	int idx;
+	unsigned long fmin = 0, fmax = ~0, ftmp;
+	const struct scpi_opp *opp = clk->info->opps;
+
+	for (idx = 0; idx < clk->info->count; idx++, opp++) {
+		ftmp = opp->freq;
+		if (ftmp >= rate) {
+			if (ftmp <= fmax)
+				fmax = ftmp;
+			break;
+		} else if (ftmp >= fmin) {
+			fmin = ftmp;
+		}
+	}
+	return fmax != ~0 ? fmax : fmin;
+}
+
+static unsigned long scpi_dvfs_recalc_rate(struct clk_hw *hw,
+					   unsigned long parent_rate)
+{
+	struct scpi_clk *clk = to_scpi_clk(hw);
+	int idx = clk->scpi_ops->dvfs_get_idx(clk->id);
+	const struct scpi_opp *opp;
+
+	if (idx < 0)
+		return 0;
+
+	opp = clk->info->opps + idx;
+	return opp->freq;
+}
+
+static long scpi_dvfs_round_rate(struct clk_hw *hw, unsigned long rate,
+				 unsigned long *parent_rate)
+{
+	struct scpi_clk *clk = to_scpi_clk(hw);
+
+	return __scpi_dvfs_round_rate(clk, rate);
+}
+
+static int __scpi_find_dvfs_index(struct scpi_clk *clk, unsigned long rate)
+{
+	int idx, max_opp = clk->info->count;
+	const struct scpi_opp *opp = clk->info->opps;
+
+	for (idx = 0; idx < max_opp; idx++, opp++)
+		if (opp->freq == rate)
+			return idx;
+	return -EINVAL;
+}
+
+static int scpi_dvfs_set_rate(struct clk_hw *hw, unsigned long rate,
+			      unsigned long parent_rate)
+{
+	struct scpi_clk *clk = to_scpi_clk(hw);
+	int ret = __scpi_find_dvfs_index(clk, rate);
+
+	if (ret < 0)
+		return ret;
+	return clk->scpi_ops->dvfs_set_idx(clk->id, (u8)ret);
+}
+
+static const struct clk_ops scpi_dvfs_ops = {
+	.recalc_rate = scpi_dvfs_recalc_rate,
+	.round_rate = scpi_dvfs_round_rate,
+	.set_rate = scpi_dvfs_set_rate,
+};
+
+static const struct of_device_id scpi_clk_match[] = {
+	{ .compatible = "arm,scpi-dvfs-clocks", .data = &scpi_dvfs_ops, },
+	{ .compatible = "arm,scpi-variable-clocks", .data = &scpi_clk_ops, },
+	{}
+};
+
+static int
+scpi_clk_ops_init(struct device *dev, const struct of_device_id *match,
+		  struct scpi_clk *sclk, const char *name)
+{
+	struct clk_init_data init;
+	unsigned long min = 0, max = 0;
+	int ret;
+
+	init.name = name;
+	init.flags = 0;
+	init.num_parents = 0;
+	init.ops = match->data;
+	sclk->hw.init = &init;
+	sclk->scpi_ops = get_scpi_ops();
+
+	if (init.ops == &scpi_dvfs_ops) {
+		sclk->info = sclk->scpi_ops->dvfs_get_info(sclk->id);
+		if (IS_ERR(sclk->info))
+			return PTR_ERR(sclk->info);
+	} else if (init.ops == &scpi_clk_ops) {
+		if (sclk->scpi_ops->clk_get_range(sclk->id, &min, &max) || !max)
+			return -EINVAL;
+	} else {
+		return -EINVAL;
+	}
+
+	ret = devm_clk_hw_register(dev, &sclk->hw);
+	if (!ret && max)
+		clk_hw_set_rate_range(&sclk->hw, min, max);
+	return ret;
+}
+
+struct scpi_clk_data {
+	struct scpi_clk **clk;
+	unsigned int clk_num;
+};
+
+static struct clk_hw *
+scpi_of_clk_src_get(struct of_phandle_args *clkspec, void *data)
+{
+	struct scpi_clk *sclk;
+	struct scpi_clk_data *clk_data = data;
+	unsigned int idx = clkspec->args[0], count;
+
+	for (count = 0; count < clk_data->clk_num; count++) {
+		sclk = clk_data->clk[count];
+		if (idx == sclk->id)
+			return &sclk->hw;
+	}
+
+	return ERR_PTR(-EINVAL);
+}
+
+static int scpi_clk_add(struct device *dev, struct device_node *np,
+			const struct of_device_id *match)
+{
+	int idx, count, err;
+	struct scpi_clk_data *clk_data;
+
+	count = of_property_count_strings(np, "clock-output-names");
+	if (count < 0) {
+		dev_err(dev, "%s: invalid clock output count\n", np->name);
+		return -EINVAL;
+	}
+
+	clk_data = devm_kmalloc(dev, sizeof(*clk_data), GFP_KERNEL);
+	if (!clk_data)
+		return -ENOMEM;
+
+	clk_data->clk_num = count;
+	clk_data->clk = devm_kcalloc(dev, count, sizeof(*clk_data->clk),
+				     GFP_KERNEL);
+	if (!clk_data->clk)
+		return -ENOMEM;
+
+	for (idx = 0; idx < count; idx++) {
+		struct scpi_clk *sclk;
+		const char *name;
+		u32 val;
+
+		sclk = devm_kzalloc(dev, sizeof(*sclk), GFP_KERNEL);
+		if (!sclk)
+			return -ENOMEM;
+
+		if (of_property_read_string_index(np, "clock-output-names",
+						  idx, &name)) {
+			dev_err(dev, "invalid clock name @ %s\n", np->name);
+			return -EINVAL;
+		}
+
+		if (of_property_read_u32_index(np, "clock-indices",
+					       idx, &val)) {
+			dev_err(dev, "invalid clock index @ %s\n", np->name);
+			return -EINVAL;
+		}
+
+		sclk->id = val;
+
+		err = scpi_clk_ops_init(dev, match, sclk, name);
+		if (err) {
+			dev_err(dev, "failed to register clock '%s'\n", name);
+			return err;
+		}
+
+		dev_dbg(dev, "Registered clock '%s'\n", name);
+		clk_data->clk[idx] = sclk;
+	}
+
+	return of_clk_add_hw_provider(np, scpi_of_clk_src_get, clk_data);
+}
+
+static int scpi_clocks_remove(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct device_node *child, *np = dev->of_node;
+
+	if (cpufreq_dev) {
+		platform_device_unregister(cpufreq_dev);
+		cpufreq_dev = NULL;
+	}
+
+	for_each_available_child_of_node(np, child)
+		of_clk_del_provider(np);
+	return 0;
+}
+
+static int scpi_clocks_probe(struct platform_device *pdev)
+{
+	int ret;
+	struct device *dev = &pdev->dev;
+	struct device_node *child, *np = dev->of_node;
+	const struct of_device_id *match;
+
+	if (!get_scpi_ops())
+		return -ENXIO;
+
+	for_each_available_child_of_node(np, child) {
+		match = of_match_node(scpi_clk_match, child);
+		if (!match)
+			continue;
+		ret = scpi_clk_add(dev, child, match);
+		if (ret) {
+			scpi_clocks_remove(pdev);
+			of_node_put(child);
+			return ret;
+		}
+
+		if (match->data != &scpi_dvfs_ops)
+			continue;
+		/* Add the virtual cpufreq device if it's DVFS clock provider */
+		cpufreq_dev = platform_device_register_simple("scpi-cpufreq",
+							      -1, NULL, 0);
+		if (IS_ERR(cpufreq_dev))
+			pr_warn("unable to register cpufreq device");
+	}
+	return 0;
+}
+
+static const struct of_device_id scpi_clocks_ids[] = {
+	{ .compatible = "arm,scpi-clocks", },
+	{}
+};
+MODULE_DEVICE_TABLE(of, scpi_clocks_ids);
+
+static struct platform_driver scpi_clocks_driver = {
+	.driver	= {
+		.name = "scpi_clocks",
+		.of_match_table = scpi_clocks_ids,
+	},
+	.probe = scpi_clocks_probe,
+	.remove = scpi_clocks_remove,
+};
+module_platform_driver(scpi_clocks_driver);
+
+MODULE_AUTHOR("Sudeep Holla <sudeep.holla@arm.com>");
+MODULE_DESCRIPTION("ARM SCPI clock driver");
+MODULE_LICENSE("GPL v2");