[RFC/PATCH 09/12] clk: qcom: Add Krait clock controller driver

[Stephen Boyd]

The Krait CPU clocks are made up of a primary mux and secondary
mux for each CPU and the L2, controlled via cp15 accessors. For
Kraits within KPSSv1 each secondary mux accepts a different aux
source, but on KPSSv2 each secondary mux accepts the same aux
source.

Signed-off-by: Stephen Boyd <sboyd@xxxxxxxxxxxxxx>
---
 drivers/clk/qcom/Kconfig    |   9 ++
 drivers/clk/qcom/Makefile   |   1 +
 drivers/clk/qcom/krait-cc.c | 366 ++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 376 insertions(+)
 create mode 100644 drivers/clk/qcom/krait-cc.c

diff --git a/drivers/clk/qcom/Kconfig b/drivers/clk/qcom/Kconfig
index 247f042dc110..6f835e406930 100644
--- a/drivers/clk/qcom/Kconfig
+++ b/drivers/clk/qcom/Kconfig
@@ -61,3 +61,12 @@ config KPSS_XCC
 	  Support for the Krait ACC and GCC clock controllers. Say Y
 	  if you want to support CPU frequency scaling on devices such
 	  as MSM8960, APQ8064, etc.
+
+config KRAITCC
+	tristate "Krait Clock Controller"
+	depends on COMMON_CLK_QCOM
+	depends on ARM
+	select KRAIT_L2_ACCESSORS
+	help
+	  Support for the Krait CPU clocks on Qualcomm devices.
+	  Say Y if you want to support CPU frequency scaling.
diff --git a/drivers/clk/qcom/Makefile b/drivers/clk/qcom/Makefile
index bb4666733bd9..e8c7f31916da 100644
--- a/drivers/clk/qcom/Makefile
+++ b/drivers/clk/qcom/Makefile
@@ -18,3 +18,4 @@ obj-$(CONFIG_MSM_MMCC_8960) += mmcc-msm8960.o
 obj-$(CONFIG_MSM_MMCC_8974) += mmcc-msm8974.o
 obj-$(CONFIG_KPSS_XCC) += kpss-xcc.o
 obj-$(CONFIG_QCOM_HFPLL) += hfpll.o
+obj-$(CONFIG_KRAITCC) += krait-cc.o
diff --git a/drivers/clk/qcom/krait-cc.c b/drivers/clk/qcom/krait-cc.c
new file mode 100644
index 000000000000..4ca9589acfca
--- /dev/null
+++ b/drivers/clk/qcom/krait-cc.c
@@ -0,0 +1,366 @@
+/* Copyright (c) 2013-2014, The Linux Foundation. All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 and
+ * only version 2 as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that 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.
+ */
+
+#include <linux/kernel.h>
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/err.h>
+#include <linux/io.h>
+#include <linux/of.h>
+#include <linux/of_device.h>
+#include <linux/clk.h>
+#include <linux/clk-provider.h>
+#include <linux/slab.h>
+
+#include <asm/smp_plat.h>
+
+#include "clk-krait.h"
+
+DEFINE_FIXED_DIV_CLK(acpu_aux, 2, "gpll0_vote");
+
+static u8 sec_mux_map[] = {
+	2,
+	0,
+};
+
+static u8 pri_mux_map[] = {
+	1,
+	2,
+	0,
+};
+
+static int
+krait_add_div(struct device *dev, int id, const char *s, unsigned offset)
+{
+	struct div_clk *div;
+	struct clk_init_data init = {
+		.num_parents = 1,
+		.ops = &clk_ops_div,
+		.flags = CLK_SET_RATE_PARENT,
+	};
+	const char *p_names[1];
+	struct clk *clk;
+
+	div = devm_kzalloc(dev, sizeof(*dev), GFP_KERNEL);
+	if (!div)
+		return -ENOMEM;
+
+	div->data.div = 2;
+	div->data.min_div = 2;
+	div->data.max_div = 2;
+	div->ops = &clk_div_ops_kpss_div2;
+	div->mask = 0x3;
+	div->shift = 6;
+	div->priv = (void *)(id >= 0);
+	div->offset = offset;
+	div->hw.init = &init;
+
+	init.name = kasprintf(GFP_KERNEL, "hfpll%s_div", s);
+	if (!init.name)
+		return -ENOMEM;
+
+	init.parent_names = p_names;
+	p_names[0] = kasprintf(GFP_KERNEL, "hfpll%s", s);
+	if (!p_names[0]) {
+		kfree(init.name);
+		return -ENOMEM;
+	}
+
+	clk = devm_clk_register(dev, &div->hw);
+	kfree(p_names[0]);
+	kfree(init.name);
+
+	return PTR_ERR_OR_ZERO(clk);
+}
+
+static int
+krait_add_sec_mux(struct device *dev, int id, const char *s, unsigned offset,
+		  bool unique_aux)
+{
+	struct mux_clk *mux;
+	static const char *sec_mux_list[] = {
+		"acpu_aux",
+		"qsb",
+	};
+	struct clk_init_data init = {
+		.parent_names = sec_mux_list,
+		.num_parents = ARRAY_SIZE(sec_mux_list),
+		.ops = &clk_ops_gen_mux,
+		.flags = CLK_SET_RATE_PARENT,
+	};
+	struct clk *clk;
+
+	mux = devm_kzalloc(dev, sizeof(*mux), GFP_KERNEL);
+	if (!mux)
+		return -ENOMEM;
+
+	mux->offset = offset;
+	mux->priv = (void *)(id >= 0);
+	mux->has_safe_parent = true;
+	mux->safe_sel = 2;
+	mux->ops = &clk_mux_ops_kpss;
+	mux->mask = 0x3;
+	mux->shift = 2;
+	mux->parent_map = sec_mux_map;
+	mux->hw.init = &init;
+
+	init.name = kasprintf(GFP_KERNEL, "krait%s_sec_mux", s);
+	if (!init.name)
+		return -ENOMEM;
+
+	if (unique_aux) {
+		sec_mux_list[0] = kasprintf(GFP_KERNEL, "acpu%s_aux", s);
+		if (!sec_mux_list[0]) {
+			clk = ERR_PTR(-ENOMEM);
+			goto err_aux;
+		}
+		pr_info("Parents are %s %s\n", sec_mux_list[0], sec_mux_list[1]);
+	}
+
+	clk = devm_clk_register(dev, &mux->hw);
+
+	if (unique_aux)
+		kfree(sec_mux_list[0]);
+err_aux:
+	kfree(init.name);
+	return PTR_ERR_OR_ZERO(clk);
+}
+
+static struct clk *
+krait_add_pri_mux(struct device *dev, int id, const char * s, unsigned offset)
+{
+	struct mux_clk *mux;
+	const char *p_names[3];
+	struct clk_init_data init = {
+		.parent_names = p_names,
+		.num_parents = ARRAY_SIZE(p_names),
+		.ops = &clk_ops_gen_mux,
+		.flags = CLK_SET_RATE_PARENT,
+	};
+	struct clk *clk;
+
+	mux = devm_kzalloc(dev, sizeof(*mux), GFP_KERNEL);
+	if (!mux)
+		return ERR_PTR(-ENOMEM);
+
+	mux->has_safe_parent = true;
+	mux->safe_sel = 0;
+	mux->ops = &clk_mux_ops_kpss;
+	mux->mask = 0x3;
+	mux->shift = 0;
+	mux->offset = offset;
+	mux->priv = (void *)(id >= 0);
+	mux->parent_map = pri_mux_map;
+	mux->hw.init = &init;
+
+	init.name = kasprintf(GFP_KERNEL, "krait%s_pri_mux", s);
+	if (!init.name)
+		return ERR_PTR(-ENOMEM);
+
+	p_names[0] = kasprintf(GFP_KERNEL, "hfpll%s", s);
+	if (!p_names[0]) {
+		clk = ERR_PTR(-ENOMEM);
+		goto err_p0;
+	}
+
+	p_names[1] = kasprintf(GFP_KERNEL, "hfpll%s_div", s);
+	if (!p_names[1]) {
+		clk = ERR_PTR(-ENOMEM);
+		goto err_p1;
+	}
+
+	p_names[2] = kasprintf(GFP_KERNEL, "krait%s_sec_mux", s);
+	if (!p_names[2]) {
+		clk = ERR_PTR(-ENOMEM);
+		goto err_p2;
+	}
+
+	clk = devm_clk_register(dev, &mux->hw);
+
+	kfree(p_names[2]);
+err_p2:
+	kfree(p_names[1]);
+err_p1:
+	kfree(p_names[0]);
+err_p0:
+	kfree(init.name);
+	return clk;
+}
+
+/* id < 0 for L2, otherwise id == physical CPU number */
+static struct clk *krait_add_clks(struct device *dev, int id, bool unique_aux)
+{
+	int ret;
+	unsigned offset;
+	const char *s;
+	struct clk *clk;
+
+	if (id >= 0) {
+		offset = 0x4501 + (0x1000 * id);
+		s = kasprintf(GFP_KERNEL, "%d", id);
+		if (!s)
+			return ERR_PTR(-ENOMEM);
+	} else {
+		offset = 0x500;
+		s = "_l2";
+	}
+
+	ret = krait_add_div(dev, id, s, offset);
+	if (ret) {
+		clk = ERR_PTR(ret);
+		goto err;
+	}
+
+	ret = krait_add_sec_mux(dev, id, s, offset, unique_aux);
+	if (ret) {
+		clk = ERR_PTR(ret);
+		goto err;
+	}
+
+	clk = krait_add_pri_mux(dev, id, s, offset);
+err:
+	if (id >= 0)
+		kfree(s);
+
+	return clk;
+}
+
+static struct clk *krait_of_get(struct of_phandle_args *clkspec, void *data)
+{
+	unsigned int idx = clkspec->args[0];
+	struct clk **clks = data;
+
+	if (idx >= 5) {
+		pr_err("%s: invalid clock index %d\n", __func__, idx);
+		return ERR_PTR(-EINVAL);
+	}
+
+	return clks[idx] ? : ERR_PTR(-ENODEV);
+}
+
+static const struct of_device_id krait_cc_match_table[] = {
+	{ .compatible = "qcom,krait-cc-v1", (void *)1UL },
+	{ .compatible = "qcom,krait-cc-v2" },
+	{}
+};
+MODULE_DEVICE_TABLE(of, krait_cc_match_table);
+
+static int krait_cc_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	const struct of_device_id *id;
+	unsigned long cur_rate, aux_rate;
+	int i, cpu;
+	struct clk *clk;
+	struct clk **clks;
+	struct clk *l2_pri_mux_clk;
+
+	id = of_match_device(krait_cc_match_table, &pdev->dev);
+	if (!id)
+		return -ENODEV;
+
+	/* Rate is 1 because 0 causes problems for __clk_mux_determine_rate */
+	clk = clk_register_fixed_rate(dev, "qsb", NULL, CLK_IS_ROOT, 1);
+	if (IS_ERR(clk))
+		return PTR_ERR(clk);
+
+	if (!id->data) {
+		clk = devm_clk_register(dev, &acpu_aux.hw);
+		if (IS_ERR(clk))
+			return PTR_ERR(clk);
+	}
+
+	/* Krait configurations have at most 4 CPUs and one L2 */
+	clks = devm_kcalloc(dev, 5, sizeof(*clks), GFP_KERNEL);
+	if (!clks)
+		return -ENOMEM;
+
+	for_each_possible_cpu(i) {
+		cpu = cpu_logical_map(i);
+		clk = krait_add_clks(dev, cpu, id->data);
+		if (IS_ERR(clk))
+			return PTR_ERR(clk);
+		clks[cpu] = clk;
+	}
+
+	l2_pri_mux_clk = krait_add_clks(dev, -1, id->data);
+	if (IS_ERR(l2_pri_mux_clk))
+		return PTR_ERR(l2_pri_mux_clk);
+	clks[4] = l2_pri_mux_clk;
+
+	/*
+	 * We don't want the CPU or L2 clocks to be turned off at late init
+	 * if CPUFREQ or HOTPLUG configs are disabled. So, bump up the
+	 * refcount of these clocks. Any cpufreq/hotplug manager can assume
+	 * that the clocks have already been prepared and enabled by the time
+	 * they take over.
+	 */
+	for_each_online_cpu(i) {
+		cpu = cpu_logical_map(i);
+		clk_prepare_enable(l2_pri_mux_clk);
+		WARN(clk_prepare_enable(clks[cpu]),
+			"Unable to turn on CPU%d clock", cpu);
+	}
+
+	/*
+	 * Force reinit of HFPLLs and muxes to overwrite any potential
+	 * incorrect configuration of HFPLLs and muxes by the bootloader.
+	 * While at it, also make sure the cores are running at known rates
+	 * and print the current rate.
+	 *
+	 * The clocks are set to aux clock rate first to make sure the
+	 * secondary mux is not sourcing off of QSB. The rate is then set to
+	 * two different rates to force a HFPLL reinit under all
+	 * circumstances.
+	 */
+	cur_rate = clk_get_rate(l2_pri_mux_clk);
+	aux_rate = 384000000;
+	if (cur_rate == 1) {
+		pr_info("L2 @ QSB rate. Forcing new rate.\n");
+		cur_rate = aux_rate;
+	}
+	clk_set_rate(l2_pri_mux_clk, aux_rate);
+	clk_set_rate(l2_pri_mux_clk, 2);
+	clk_set_rate(l2_pri_mux_clk, cur_rate);
+	pr_info("L2 @ %lu KHz\n", clk_get_rate(l2_pri_mux_clk) / 1000);
+	for_each_possible_cpu(i) {
+		cpu = cpu_logical_map(i);
+		clk = clks[cpu];
+		cur_rate = clk_get_rate(clk);
+		if (cur_rate == 1) {
+			pr_info("CPU%d @ QSB rate. Forcing new rate.\n", i);
+			cur_rate = aux_rate;
+		}
+		clk_set_rate(clk, aux_rate);
+		clk_set_rate(clk, 2);
+		clk_set_rate(clk, cur_rate);
+		pr_info("CPU%d @ %lu KHz\n", i, clk_get_rate(clk) / 1000);
+	}
+
+	of_clk_add_provider(dev->of_node, krait_of_get, clks);
+
+	return 0;
+}
+
+static struct platform_driver krait_cc_driver = {
+	.probe = krait_cc_probe,
+	.driver = {
+		.name = "clock-krait",
+		.of_match_table = krait_cc_match_table,
+		.owner = THIS_MODULE,
+	},
+};
+module_platform_driver(krait_cc_driver);
+
+MODULE_DESCRIPTION("Krait CPU Clock Driver");
+MODULE_LICENSE("GPL v2");
-- 
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