clk: tegra: Add BPMP clock driver

This driver uses the services provided by the BPMP firmware driver to
implement a clock driver based on the MRQ_CLK request. This part of the
BPMP ABI provides a means to enumerate and control clocks and should
allow the driver to work on any chip that supports this ABI.

Signed-off-by: Thierry Reding <treding@nvidia.com>
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>

drivers/clk/tegra/Kconfig

@@ -1,3 +1,7 @@
 config TEGRA_CLK_EMC
 	def_bool y
 	depends on TEGRA124_EMC
+
+config CLK_TEGRA_BPMP
+	def_bool y
+	depends on TEGRA_BPMP

drivers/clk/tegra/Makefile

@@ -22,3 +22,4 @@ obj-$(CONFIG_ARCH_TEGRA_124_SOC)	+= clk-tegra124-dfll-fcpu.o
 obj-$(CONFIG_ARCH_TEGRA_132_SOC)	+= clk-tegra124.o
 obj-y					+= cvb.o
 obj-$(CONFIG_ARCH_TEGRA_210_SOC)	+= clk-tegra210.o
+obj-$(CONFIG_CLK_TEGRA_BPMP)		+= clk-bpmp.o

drivers/clk/tegra/clk-bpmp.c

@@ -0,0 +1,620 @@
+/*
+ * Copyright (C) 2016 NVIDIA Corporation
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#include <linux/clk-provider.h>
+#include <linux/device.h>
+#include <linux/seq_buf.h>
+#include <linux/slab.h>
+
+#include <soc/tegra/bpmp.h>
+#include <soc/tegra/bpmp-abi.h>
+
+#define TEGRA_BPMP_DUMP_CLOCK_INFO	0
+
+#define TEGRA_BPMP_CLK_HAS_MUX		BIT(0)
+#define TEGRA_BPMP_CLK_HAS_SET_RATE	BIT(1)
+#define TEGRA_BPMP_CLK_IS_ROOT		BIT(2)
+
+struct tegra_bpmp_clk_info {
+	unsigned int id;
+	char name[MRQ_CLK_NAME_MAXLEN];
+	unsigned int parents[MRQ_CLK_MAX_PARENTS];
+	unsigned int num_parents;
+	unsigned long flags;
+};
+
+struct tegra_bpmp_clk {
+	struct clk_hw hw;
+
+	struct tegra_bpmp *bpmp;
+	unsigned int id;
+
+	unsigned int num_parents;
+	unsigned int *parents;
+};
+
+static inline struct tegra_bpmp_clk *to_tegra_bpmp_clk(struct clk_hw *hw)
+{
+	return container_of(hw, struct tegra_bpmp_clk, hw);
+}
+
+struct tegra_bpmp_clk_message {
+	unsigned int cmd;
+	unsigned int id;
+
+	struct {
+		const void *data;
+		size_t size;
+	} tx;
+
+	struct {
+		void *data;
+		size_t size;
+	} rx;
+};
+
+static int tegra_bpmp_clk_transfer(struct tegra_bpmp *bpmp,
+				   const struct tegra_bpmp_clk_message *clk)
+{
+	struct mrq_clk_request request;
+	struct tegra_bpmp_message msg;
+	void *req = &request;
+
+	memset(&request, 0, sizeof(request));
+	request.cmd_and_id = (clk->cmd << 24) | clk->id;
+
+	/*
+	 * The mrq_clk_request structure has an anonymous union at offset 4
+	 * that contains all possible sub-command structures. Copy the data
+	 * to that union. Ideally we'd be able to refer to it by name, but
+	 * doing so would require changing the ABI header and increase the
+	 * maintenance burden.
+	 */
+	memcpy(req + 4, clk->tx.data, clk->tx.size);
+
+	memset(&msg, 0, sizeof(msg));
+	msg.mrq = MRQ_CLK;
+	msg.tx.data = &request;
+	msg.tx.size = sizeof(request);
+	msg.rx.data = clk->rx.data;
+	msg.rx.size = clk->rx.size;
+
+	return tegra_bpmp_transfer(bpmp, &msg);
+}
+
+static int tegra_bpmp_clk_prepare(struct clk_hw *hw)
+{
+	struct tegra_bpmp_clk *clk = to_tegra_bpmp_clk(hw);
+	struct tegra_bpmp_clk_message msg;
+
+	memset(&msg, 0, sizeof(msg));
+	msg.cmd = CMD_CLK_ENABLE;
+	msg.id = clk->id;
+
+	return tegra_bpmp_clk_transfer(clk->bpmp, &msg);
+}
+
+static void tegra_bpmp_clk_unprepare(struct clk_hw *hw)
+{
+	struct tegra_bpmp_clk *clk = to_tegra_bpmp_clk(hw);
+	struct tegra_bpmp_clk_message msg;
+	int err;
+
+	memset(&msg, 0, sizeof(msg));
+	msg.cmd = CMD_CLK_DISABLE;
+	msg.id = clk->id;
+
+	err = tegra_bpmp_clk_transfer(clk->bpmp, &msg);
+	if (err < 0)
+		dev_err(clk->bpmp->dev, "failed to disable clock %s: %d\n",
+			clk_hw_get_name(hw), err);
+}
+
+static int tegra_bpmp_clk_is_prepared(struct clk_hw *hw)
+{
+	struct tegra_bpmp_clk *clk = to_tegra_bpmp_clk(hw);
+	struct cmd_clk_is_enabled_response response;
+	struct tegra_bpmp_clk_message msg;
+	int err;
+
+	memset(&msg, 0, sizeof(msg));
+	msg.cmd = CMD_CLK_IS_ENABLED;
+	msg.id = clk->id;
+	msg.rx.data = &response;
+	msg.rx.size = sizeof(response);
+
+	err = tegra_bpmp_clk_transfer(clk->bpmp, &msg);
+	if (err < 0)
+		return err;
+
+	return response.state;
+}
+
+static unsigned long tegra_bpmp_clk_recalc_rate(struct clk_hw *hw,
+						unsigned long parent_rate)
+{
+	struct tegra_bpmp_clk *clk = to_tegra_bpmp_clk(hw);
+	struct cmd_clk_get_rate_response response;
+	struct cmd_clk_get_rate_request request;
+	struct tegra_bpmp_clk_message msg;
+	int err;
+
+	memset(&msg, 0, sizeof(msg));
+	msg.cmd = CMD_CLK_GET_RATE;
+	msg.id = clk->id;
+	msg.tx.data = &request;
+	msg.tx.size = sizeof(request);
+	msg.rx.data = &response;
+	msg.rx.size = sizeof(response);
+
+	err = tegra_bpmp_clk_transfer(clk->bpmp, &msg);
+	if (err < 0)
+		return err;
+
+	return response.rate;
+}
+
+static long tegra_bpmp_clk_round_rate(struct clk_hw *hw, unsigned long rate,
+				      unsigned long *parent_rate)
+{
+	struct tegra_bpmp_clk *clk = to_tegra_bpmp_clk(hw);
+	struct cmd_clk_round_rate_response response;
+	struct cmd_clk_round_rate_request request;
+	struct tegra_bpmp_clk_message msg;
+	int err;
+
+	memset(&request, 0, sizeof(request));
+	request.rate = rate;
+
+	memset(&msg, 0, sizeof(msg));
+	msg.cmd = CMD_CLK_ROUND_RATE;
+	msg.id = clk->id;
+	msg.tx.data = &request;
+	msg.tx.size = sizeof(request);
+	msg.rx.data = &response;
+	msg.rx.size = sizeof(response);
+
+	err = tegra_bpmp_clk_transfer(clk->bpmp, &msg);
+	if (err < 0)
+		return err;
+
+	return response.rate;
+}
+
+static int tegra_bpmp_clk_set_parent(struct clk_hw *hw, u8 index)
+{
+	struct tegra_bpmp_clk *clk = to_tegra_bpmp_clk(hw);
+	struct cmd_clk_set_parent_response response;
+	struct cmd_clk_set_parent_request request;
+	struct tegra_bpmp_clk_message msg;
+	int err;
+
+	memset(&request, 0, sizeof(request));
+	request.parent_id = clk->parents[index];
+
+	memset(&msg, 0, sizeof(msg));
+	msg.cmd = CMD_CLK_SET_PARENT;
+	msg.id = clk->id;
+	msg.tx.data = &request;
+	msg.tx.size = sizeof(request);
+	msg.rx.data = &response;
+	msg.rx.size = sizeof(response);
+
+	err = tegra_bpmp_clk_transfer(clk->bpmp, &msg);
+	if (err < 0)
+		return err;
+
+	/* XXX check parent ID in response */
+
+	return 0;
+}
+
+static u8 tegra_bpmp_clk_get_parent(struct clk_hw *hw)
+{
+	struct tegra_bpmp_clk *clk = to_tegra_bpmp_clk(hw);
+	struct cmd_clk_get_parent_response response;
+	struct tegra_bpmp_clk_message msg;
+	unsigned int i;
+	int err;
+
+	memset(&msg, 0, sizeof(msg));
+	msg.cmd = CMD_CLK_GET_PARENT;
+	msg.id = clk->id;
+	msg.rx.data = &response;
+	msg.rx.size = sizeof(response);
+
+	err = tegra_bpmp_clk_transfer(clk->bpmp, &msg);
+	if (err < 0) {
+		dev_err(clk->bpmp->dev, "failed to get parent for %s: %d\n",
+			clk_hw_get_name(hw), err);
+		return U8_MAX;
+	}
+
+	for (i = 0; i < clk->num_parents; i++)
+		if (clk->parents[i] == response.parent_id)
+			return i;
+
+	return U8_MAX;
+}
+
+static int tegra_bpmp_clk_set_rate(struct clk_hw *hw, unsigned long rate,
+				   unsigned long parent_rate)
+{
+	struct tegra_bpmp_clk *clk = to_tegra_bpmp_clk(hw);
+	struct cmd_clk_set_rate_response response;
+	struct cmd_clk_set_rate_request request;
+	struct tegra_bpmp_clk_message msg;
+
+	memset(&request, 0, sizeof(request));
+	request.rate = rate;
+
+	memset(&msg, 0, sizeof(msg));
+	msg.cmd = CMD_CLK_SET_RATE;
+	msg.id = clk->id;
+	msg.tx.data = &request;
+	msg.tx.size = sizeof(request);
+	msg.rx.data = &response;
+	msg.rx.size = sizeof(response);
+
+	return tegra_bpmp_clk_transfer(clk->bpmp, &msg);
+}
+
+static const struct clk_ops tegra_bpmp_clk_gate_ops = {
+	.prepare = tegra_bpmp_clk_prepare,
+	.unprepare = tegra_bpmp_clk_unprepare,
+	.is_prepared = tegra_bpmp_clk_is_prepared,
+	.recalc_rate = tegra_bpmp_clk_recalc_rate,
+};
+
+static const struct clk_ops tegra_bpmp_clk_mux_ops = {
+	.prepare = tegra_bpmp_clk_prepare,
+	.unprepare = tegra_bpmp_clk_unprepare,
+	.is_prepared = tegra_bpmp_clk_is_prepared,
+	.recalc_rate = tegra_bpmp_clk_recalc_rate,
+	.set_parent = tegra_bpmp_clk_set_parent,
+	.get_parent = tegra_bpmp_clk_get_parent,
+};
+
+static const struct clk_ops tegra_bpmp_clk_rate_ops = {
+	.prepare = tegra_bpmp_clk_prepare,
+	.unprepare = tegra_bpmp_clk_unprepare,
+	.is_prepared = tegra_bpmp_clk_is_prepared,
+	.recalc_rate = tegra_bpmp_clk_recalc_rate,
+	.round_rate = tegra_bpmp_clk_round_rate,
+	.set_rate = tegra_bpmp_clk_set_rate,
+};
+
+static const struct clk_ops tegra_bpmp_clk_mux_rate_ops = {
+	.prepare = tegra_bpmp_clk_prepare,
+	.unprepare = tegra_bpmp_clk_unprepare,
+	.is_prepared = tegra_bpmp_clk_is_prepared,
+	.recalc_rate = tegra_bpmp_clk_recalc_rate,
+	.round_rate = tegra_bpmp_clk_round_rate,
+	.set_parent = tegra_bpmp_clk_set_parent,
+	.get_parent = tegra_bpmp_clk_get_parent,
+	.set_rate = tegra_bpmp_clk_set_rate,
+};
+
+static int tegra_bpmp_clk_get_max_id(struct tegra_bpmp *bpmp)
+{
+	struct cmd_clk_get_max_clk_id_response response;
+	struct tegra_bpmp_clk_message msg;
+	int err;
+
+	memset(&msg, 0, sizeof(msg));
+	msg.cmd = CMD_CLK_GET_MAX_CLK_ID;
+	msg.rx.data = &response;
+	msg.rx.size = sizeof(response);
+
+	err = tegra_bpmp_clk_transfer(bpmp, &msg);
+	if (err < 0)
+		return err;
+
+	if (response.max_id > INT_MAX)
+		return -E2BIG;
+
+	return response.max_id;
+}
+
+static int tegra_bpmp_clk_get_info(struct tegra_bpmp *bpmp, unsigned int id,
+				   struct tegra_bpmp_clk_info *info)
+{
+	struct cmd_clk_get_all_info_response response;
+	struct tegra_bpmp_clk_message msg;
+	unsigned int i;
+	int err;
+
+	memset(&msg, 0, sizeof(msg));
+	msg.cmd = CMD_CLK_GET_ALL_INFO;
+	msg.id = id;
+	msg.rx.data = &response;
+	msg.rx.size = sizeof(response);
+
+	err = tegra_bpmp_clk_transfer(bpmp, &msg);
+	if (err < 0)
+		return err;
+
+	strlcpy(info->name, response.name, MRQ_CLK_NAME_MAXLEN);
+	info->num_parents = response.num_parents;
+
+	for (i = 0; i < info->num_parents; i++)
+		info->parents[i] = response.parents[i];
+
+	info->flags = response.flags;
+
+	return 0;
+}
+
+static void tegra_bpmp_clk_info_dump(struct tegra_bpmp *bpmp,
+				     const char *level,
+				     const struct tegra_bpmp_clk_info *info)
+{
+	const char *prefix = "";
+	struct seq_buf buf;
+	unsigned int i;
+	char flags[64];
+
+	seq_buf_init(&buf, flags, sizeof(flags));
+
+	if (info->flags)
+		seq_buf_printf(&buf, "(");
+
+	if (info->flags & TEGRA_BPMP_CLK_HAS_MUX) {
+		seq_buf_printf(&buf, "%smux", prefix);
+		prefix = ", ";
+	}
+
+	if ((info->flags & TEGRA_BPMP_CLK_HAS_SET_RATE) == 0) {
+		seq_buf_printf(&buf, "%sfixed", prefix);
+		prefix = ", ";
+	}
+
+	if (info->flags & TEGRA_BPMP_CLK_IS_ROOT) {
+		seq_buf_printf(&buf, "%sroot", prefix);
+		prefix = ", ";
+	}
+
+	if (info->flags)
+		seq_buf_printf(&buf, ")");
+
+	dev_printk(level, bpmp->dev, "%03u: %s\n", info->id, info->name);
+	dev_printk(level, bpmp->dev, "  flags: %lx %s\n", info->flags, flags);
+	dev_printk(level, bpmp->dev, "  parents: %u\n", info->num_parents);
+
+	for (i = 0; i < info->num_parents; i++)
+		dev_printk(level, bpmp->dev, "    %03u\n", info->parents[i]);
+}
+
+static int tegra_bpmp_probe_clocks(struct tegra_bpmp *bpmp,
+				   struct tegra_bpmp_clk_info **clocksp)
+{
+	struct tegra_bpmp_clk_info *clocks;
+	unsigned int max_id, id, count = 0;
+	unsigned int holes = 0;
+	int err;
+
+	err = tegra_bpmp_clk_get_max_id(bpmp);
+	if (err < 0)
+		return err;
+
+	max_id = err;
+
+	dev_dbg(bpmp->dev, "maximum clock ID: %u\n", max_id);
+
+	clocks = kcalloc(max_id + 1, sizeof(*clocks), GFP_KERNEL);
+	if (!clocks)
+		return -ENOMEM;
+
+	for (id = 0; id <= max_id; id++) {
+		struct tegra_bpmp_clk_info *info = &clocks[count];
+
+		err = tegra_bpmp_clk_get_info(bpmp, id, info);
+		if (err < 0) {
+			dev_err(bpmp->dev, "failed to query clock %u: %d\n",
+				id, err);
+			continue;
+		}
+
+		if (info->num_parents >= U8_MAX) {
+			dev_err(bpmp->dev,
+				"clock %u has too many parents (%u, max: %u)\n",
+				id, info->num_parents, U8_MAX);
+			continue;
+		}
+
+		/* clock not exposed by BPMP */
+		if (info->name[0] == '\0') {
+			holes++;
+			continue;
+		}
+
+		info->id = id;
+		count++;
+
+		if (TEGRA_BPMP_DUMP_CLOCK_INFO)
+			tegra_bpmp_clk_info_dump(bpmp, KERN_DEBUG, info);
+	}
+
+	dev_dbg(bpmp->dev, "holes: %u\n", holes);
+	*clocksp = clocks;
+
+	return count;
+}
+
+static const struct tegra_bpmp_clk_info *
+tegra_bpmp_clk_find(const struct tegra_bpmp_clk_info *clocks,
+		    unsigned int num_clocks, unsigned int id)
+{
+	unsigned int i;
+
+	for (i = 0; i < num_clocks; i++)
+		if (clocks[i].id == id)
+			return &clocks[i];
+
+	return NULL;
+}
+
+static struct tegra_bpmp_clk *
+tegra_bpmp_clk_register(struct tegra_bpmp *bpmp,
+			const struct tegra_bpmp_clk_info *info,
+			const struct tegra_bpmp_clk_info *clocks,
+			unsigned int num_clocks)
+{
+	struct tegra_bpmp_clk *clk;
+	struct clk_init_data init;
+	const char **parents;
+	unsigned int i;
+	int err;
+
+	clk = devm_kzalloc(bpmp->dev, sizeof(*clk), GFP_KERNEL);
+	if (!clk)
+		return ERR_PTR(-ENOMEM);
+
+	clk->id = info->id;
+	clk->bpmp = bpmp;
+
+	clk->parents = devm_kcalloc(bpmp->dev, info->num_parents,
+				    sizeof(*clk->parents), GFP_KERNEL);
+	if (!clk->parents)
+		return ERR_PTR(-ENOMEM);
+
+	clk->num_parents = info->num_parents;
+
+	/* hardware clock initialization */
+	memset(&init, 0, sizeof(init));
+	init.name = info->name;
+	clk->hw.init = &init;
+
+	if (info->flags & TEGRA_BPMP_CLK_HAS_MUX) {
+		if (info->flags & TEGRA_BPMP_CLK_HAS_SET_RATE)
+			init.ops = &tegra_bpmp_clk_mux_rate_ops;
+		else
+			init.ops = &tegra_bpmp_clk_mux_ops;
+	} else {
+		if (info->flags & TEGRA_BPMP_CLK_HAS_SET_RATE)
+			init.ops = &tegra_bpmp_clk_rate_ops;
+		else
+			init.ops = &tegra_bpmp_clk_gate_ops;
+	}
+
+	init.num_parents = info->num_parents;
+
+	parents = kcalloc(info->num_parents, sizeof(*parents), GFP_KERNEL);
+	if (!parents)
+		return ERR_PTR(-ENOMEM);
+
+	for (i = 0; i < info->num_parents; i++) {
+		const struct tegra_bpmp_clk_info *parent;
+
+		/* keep a private copy of the ID to parent index map */
+		clk->parents[i] = info->parents[i];
+
+		parent = tegra_bpmp_clk_find(clocks, num_clocks,
+					     info->parents[i]);
+		if (!parent) {
+			dev_err(bpmp->dev, "no parent %u found for %u\n",
+				info->parents[i], info->id);
+			continue;
+		}
+
+		parents[i] = parent->name;
+	}
+
+	init.parent_names = parents;
+
+	err = devm_clk_hw_register(bpmp->dev, &clk->hw);
+
+	kfree(parents);
+
+	if (err < 0)
+		return ERR_PTR(err);
+
+	return clk;
+}
+
+static int tegra_bpmp_register_clocks(struct tegra_bpmp *bpmp,
+				      struct tegra_bpmp_clk_info *infos,
+				      unsigned int count)
+{
+	struct tegra_bpmp_clk *clk;
+	unsigned int i;
+
+	bpmp->num_clocks = count;
+
+	bpmp->clocks = devm_kcalloc(bpmp->dev, count, sizeof(clk), GFP_KERNEL);
+	if (!bpmp->clocks)
+		return -ENOMEM;
+
+	for (i = 0; i < count; i++) {
+		struct tegra_bpmp_clk_info *info = &infos[i];
+
+		clk = tegra_bpmp_clk_register(bpmp, info, infos, count);
+		if (IS_ERR(clk)) {
+			dev_err(bpmp->dev,
+				"failed to register clock %u (%s): %ld\n",
+				info->id, info->name, PTR_ERR(clk));
+			continue;
+		}
+
+		bpmp->clocks[i] = clk;
+	}
+
+	return 0;
+}
+
+static void tegra_bpmp_unregister_clocks(struct tegra_bpmp *bpmp)
+{
+	unsigned int i;
+
+	for (i = 0; i < bpmp->num_clocks; i++)
+		clk_hw_unregister(&bpmp->clocks[i]->hw);
+}
+
+static struct clk_hw *tegra_bpmp_clk_of_xlate(struct of_phandle_args *clkspec,
+					      void *data)
+{
+	unsigned int id = clkspec->args[0], i;
+	struct tegra_bpmp *bpmp = data;
+
+	for (i = 0; i < bpmp->num_clocks; i++)
+		if (bpmp->clocks[i]->id == id)
+			return &bpmp->clocks[i]->hw;
+
+	return NULL;
+}
+
+int tegra_bpmp_init_clocks(struct tegra_bpmp *bpmp)
+{
+	struct tegra_bpmp_clk_info *clocks;
+	unsigned int count;
+	int err;
+
+	err = tegra_bpmp_probe_clocks(bpmp, &clocks);
+	if (err < 0)
+		return err;
+
+	count = err;
+
+	dev_dbg(bpmp->dev, "%u clocks probed\n", count);
+
+	err = tegra_bpmp_register_clocks(bpmp, clocks, count);
+	if (err < 0)
+		goto free;
+
+	err = of_clk_add_hw_provider(bpmp->dev->of_node,
+				     tegra_bpmp_clk_of_xlate,
+				     bpmp);
+	if (err < 0) {
+		tegra_bpmp_unregister_clocks(bpmp);
+		goto free;
+	}
+
+free:
+	kfree(clocks);
+	return err;
+}