Subject: [PATCH v3 03/10] clk: qcom: Add CPU clock driver for msm8996

From: [email-masked] (Ilia Lin)
Date: Wed, 14 Feb 2018 15:59:45 +0200

From: Rajendra Nayak <[email-masked]>

Each of the CPU clusters (Power and Perf) on msm8996 are
clocked via 2 PLLs, a primary and alternate. There are also
2 Mux'es, a primary and secondary all connected together
as shown below

                             +-------+
              XO             |       |
          +------------------>0      |
                             |       |
                   PLL/2     | SMUX  +----+
                     +------->1      |    |
                     |       |       |    |
                     |       +-------+    |    +-------+
                     |                    +---->0      |
                     |                         |       |
+---------------+    |             +----------->1      | CPU clk
|Primary PLL    +----+ PLL_EARLY   |           |       +------>
|               +------+-----------+    +------>2 PMUX |
+---------------+      |                |      |       |
                       |   +------+     |   +-->3      |
                       +--^+  ACD +-----+   |  +-------+
+---------------+          +------+         |
|Alt PLL        |                           |
|               +---------------------------+
+---------------+         PLL_EARLY

The primary PLL is what drives the CPU clk, except for times
when we are reprogramming the PLL itself (for rate changes) when
we temporarily switch to an alternate PLL. A subsequent patch adds
support to switch between primary and alternate PLL during rate
changes.

The primary PLL operates on a single VCO range, between 600Mhz
and 3Ghz. However the CPUs do support OPPs with frequencies
between 300Mhz and 600Mhz. In order to support running the CPUs
at those frequencies we end up having to lock the PLL at twice
the rate and drive the CPU clk via the PLL/2 output and SMUX.

So for frequencies above 600Mhz we follow the following path
 Primary PLL --> PLL_EARLY --> PMUX(1) --> CPU clk
and for frequencies between 300Mhz and 600Mhz we follow
 Primary PLL --> PLL/2 --> SMUX(1) --> PMUX(0) --> CPU clk
Support for this is added in a subsequent patch as well.

ACD stands for Adaptive Clock Distribution and is used to
detect voltage droops. We do not add support for ACD as yet.
This can be added at a later point as needed.

Signed-off-by: Rajendra Nayak <[email-masked]>
Signed-off-by: Ilia Lin <[email-masked]>
---
 drivers/clk/qcom/Kconfig        |   8 +
 drivers/clk/qcom/Makefile       |   1 +
 drivers/clk/qcom/clk-cpu-8996.c | 409 ++++++++++++++++++++++++++++++++++++++++
 3 files changed, 418 insertions(+)
 create mode 100644 drivers/clk/qcom/clk-cpu-8996.c

diff --git a/drivers/clk/qcom/Kconfig b/drivers/clk/qcom/Kconfig
index fbf4532..3274877 100644
--- a/drivers/clk/qcom/Kconfig
+++ b/drivers/clk/qcom/Kconfig
@@ -226,3 +226,11 @@ config SPMI_PMIC_CLKDIV
 	  Technologies, Inc. SPMI PMIC. It configures the frequency of
 	  clkdiv outputs of the PMIC. These clocks are typically wired
 	  through alternate functions on GPIO pins.
+
+config MSM_APCC_8996
+	tristate "MSM8996 CPU Clock Controller"
+	depends on COMMON_CLK_QCOM
+	help
+	  Support for the CPU clock controller on msm8996 devices.
+	  Say Y if you want to support CPU clock scaling using CPUfreq
+	  drivers for dyanmic power management.
diff --git a/drivers/clk/qcom/Makefile b/drivers/clk/qcom/Makefile
index 230332c..57b38ba 100644
--- a/drivers/clk/qcom/Makefile
+++ b/drivers/clk/qcom/Makefile
@@ -33,6 +33,7 @@ obj-$(CONFIG_MSM_LCC_8960) += lcc-msm8960.o
 obj-$(CONFIG_MSM_MMCC_8960) += mmcc-msm8960.o
 obj-$(CONFIG_MSM_MMCC_8974) += mmcc-msm8974.o
 obj-$(CONFIG_MSM_MMCC_8996) += mmcc-msm8996.o
+obj-$(CONFIG_MSM_APCC_8996) += clk-cpu-8996.o
 obj-$(CONFIG_QCOM_A53PLL) += a53-pll.o
 obj-$(CONFIG_QCOM_CLK_APCS_MSM8916) += apcs-msm8916.o
 obj-$(CONFIG_QCOM_CLK_RPM) += clk-rpm.o
diff --git a/drivers/clk/qcom/clk-cpu-8996.c b/drivers/clk/qcom/clk-cpu-8996.c
new file mode 100644
index 0000000..42489f1
--- /dev/null
+++ b/drivers/clk/qcom/clk-cpu-8996.c
@@ -0,0 +1,409 @@
+/*
+ * Copyright (c) 2018, 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/clk.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/regmap.h>
+
+#include "clk-alpha-pll.h"
+
+#define VCO(a, b, c) { \
+	.val = a,\
+	.min_freq = b,\
+	.max_freq = c,\
+}
+
+#define DIV_2_INDEX		0
+#define PLL_INDEX		1
+#define ACD_INDEX		2
+#define ALT_INDEX		3
+
+static const u8 prim_pll_regs[PLL_OFF_MAX_REGS] = {
+       [PLL_OFF_L_VAL] = 0x04,
+       [PLL_OFF_ALPHA_VAL] = 0x08,
+       [PLL_OFF_USER_CTL] = 0x10,
+       [PLL_OFF_CONFIG_CTL] = 0x18,
+       [PLL_OFF_CONFIG_CTL_U] = 0x1C,
+       [PLL_OFF_TEST_CTL] = 0x20,
+       [PLL_OFF_TEST_CTL_U] = 0x24,
+       [PLL_OFF_STATUS] = 0x28,
+};
+
+static const u8 alt_pll_regs[PLL_OFF_MAX_REGS] = {
+       [PLL_OFF_L_VAL] = 0x04,
+       [PLL_OFF_ALPHA_VAL] = 0x08,
+       [PLL_OFF_ALPHA_VAL_U] = 0x0c,
+       [PLL_OFF_USER_CTL] = 0x10,
+       [PLL_OFF_USER_CTL_U] = 0x14,
+       [PLL_OFF_CONFIG_CTL] = 0x18,
+       [PLL_OFF_TEST_CTL] = 0x20,
+       [PLL_OFF_TEST_CTL_U] = 0x24,
+       [PLL_OFF_STATUS] = 0x28,
+};
+
+/* PLLs */
+
+static const struct alpha_pll_config hfpll_config = {
+	.l = 60,
+	.config_ctl_val = 0x200d4828,
+	.config_ctl_hi_val = 0x006,
+	.pre_div_mask = BIT(12),
+	.post_div_mask = 0x3 << 8,
+	.main_output_mask = BIT(0),
+	.early_output_mask = BIT(3),
+};
+
+static struct clk_alpha_pll perfcl_pll = {
+	.offset = 0x80000,
+	.regs = prim_pll_regs,
+	.flags = SUPPORTS_DYNAMIC_UPDATE | SUPPORTS_FSM_MODE,
+	.clkr.hw.init = &(struct clk_init_data){
+		.name = "perfcl_pll",
+		.parent_names = (const char *[]){ "xo" },
+		.num_parents = 1,
+		.ops = &clk_alpha_pll_huayra_ops,
+	},
+};
+
+static struct clk_alpha_pll pwrcl_pll = {
+	.offset = 0x0,
+	.regs = prim_pll_regs,
+	.flags = SUPPORTS_DYNAMIC_UPDATE | SUPPORTS_FSM_MODE,
+	.clkr.hw.init = &(struct clk_init_data){
+		.name = "pwrcl_pll",
+		.parent_names = (const char *[]){ "xo" },
+		.num_parents = 1,
+		.ops = &clk_alpha_pll_huayra_ops,
+	},
+};
+
+static const struct pll_vco alt_pll_vco_modes[] = {
+	VCO(3,  250000000,  500000000),
+	VCO(2,  500000000,  750000000),
+	VCO(1,  750000000, 1000000000),
+	VCO(0, 1000000000, 2150400000),
+};
+
+static const struct alpha_pll_config altpll_config = {
+	.l = 16,
+	.vco_val = 0x3 << 20,
+	.vco_mask = 0x3 << 20,
+	.config_ctl_val = 0x4001051b,
+	.post_div_mask = 0x3 << 8,
+	.post_div_val = 0x1,
+	.main_output_mask = BIT(0),
+	.early_output_mask = BIT(3),
+};
+
+static struct clk_alpha_pll perfcl_alt_pll = {
+	.offset = 0x80100,
+	.regs = alt_pll_regs,
+	.vco_table = alt_pll_vco_modes,
+	.num_vco = ARRAY_SIZE(alt_pll_vco_modes),
+	.flags = SUPPORTS_OFFLINE_REQ | SUPPORTS_FSM_MODE,
+	.clkr.hw.init = &(struct clk_init_data) {
+		.name = "perfcl_alt_pll",
+		.parent_names = (const char *[]){ "xo" },
+		.num_parents = 1,
+		.ops = &clk_alpha_pll_hwfsm_ops,
+	},
+};
+
+static struct clk_alpha_pll pwrcl_alt_pll = {
+	.offset = 0x100,
+	.regs = alt_pll_regs,
+	.vco_table = alt_pll_vco_modes,
+	.num_vco = ARRAY_SIZE(alt_pll_vco_modes),
+	.flags = SUPPORTS_OFFLINE_REQ | SUPPORTS_FSM_MODE,
+	.clkr.hw.init = &(struct clk_init_data) {
+		.name = "pwrcl_alt_pll",
+		.parent_names = (const char *[]){ "xo" },
+		.num_parents = 1,
+		.ops = &clk_alpha_pll_hwfsm_ops,
+	},
+};
+
+/* Mux'es */
+
+struct clk_cpu_8996_mux {
+	u32	reg;
+	u32	shift;
+	u32	width;
+	struct clk_hw	*pll;
+	struct clk_regmap clkr;
+};
+
+static inline
+struct clk_cpu_8996_mux *to_clk_cpu_8996_mux_hw(struct clk_hw *hw)
+{
+	return container_of(to_clk_regmap(hw), struct clk_cpu_8996_mux, clkr);
+}
+
+static u8 clk_cpu_8996_mux_get_parent(struct clk_hw *hw)
+{
+	unsigned int val;
+	struct clk_regmap *clkr = to_clk_regmap(hw);
+	struct clk_cpu_8996_mux *cpuclk = to_clk_cpu_8996_mux_hw(hw);
+	unsigned int mask = GENMASK(cpuclk->width - 1, 0);
+
+	regmap_read(clkr->regmap, cpuclk->reg, &val);
+
+	val >>= cpuclk->shift;
+	val &= mask;
+
+	return val;
+}
+
+static int clk_cpu_8996_mux_set_parent(struct clk_hw *hw, u8 index)
+{
+	unsigned int val;
+	struct clk_regmap *clkr = to_clk_regmap(hw);
+	struct clk_cpu_8996_mux *cpuclk = to_clk_cpu_8996_mux_hw(hw);
+	unsigned int mask = GENMASK(cpuclk->width + cpuclk->shift - 1,
+				    cpuclk->shift);
+
+	val = index;
+	val <<= cpuclk->shift;
+
+	return regmap_update_bits(clkr->regmap, cpuclk->reg, mask, val);
+}
+
+static int
+clk_cpu_8996_mux_determine_rate(struct clk_hw *hw, struct clk_rate_request *req)
+{
+	struct clk_cpu_8996_mux *cpuclk = to_clk_cpu_8996_mux_hw(hw);
+	struct clk_hw *parent = cpuclk->pll;
+
+	if (!cpuclk->pll)
+		return -EINVAL;
+
+	req->best_parent_rate = clk_hw_round_rate(parent, req->rate);
+	req->best_parent_hw = parent;
+
+	return 0;
+}
+
+const struct clk_ops clk_cpu_8996_mux_ops = {
+	.set_parent = clk_cpu_8996_mux_set_parent,
+	.get_parent = clk_cpu_8996_mux_get_parent,
+	.determine_rate = clk_cpu_8996_mux_determine_rate,
+};
+
+static struct clk_cpu_8996_mux pwrcl_smux = {
+	.reg = 0x40,
+	.shift = 2,
+	.width = 2,
+	.clkr.hw.init = &(struct clk_init_data) {
+		.name = "pwrcl_smux",
+		.parent_names = (const char *[]){
+			"xo",
+			"pwrcl_pll_main",
+		},
+		.num_parents = 2,
+		.ops = &clk_cpu_8996_mux_ops,
+		.flags = CLK_SET_RATE_PARENT,
+	},
+};
+
+static struct clk_cpu_8996_mux perfcl_smux = {
+	.reg = 0x80040,
+	.shift = 2,
+	.width = 2,
+	.clkr.hw.init = &(struct clk_init_data) {
+		.name = "perfcl_smux",
+		.parent_names = (const char *[]){
+			"xo",
+			"perfcl_pll_main",
+		},
+		.num_parents = 2,
+		.ops = &clk_cpu_8996_mux_ops,
+		.flags = CLK_SET_RATE_PARENT,
+	},
+};
+
+static struct clk_cpu_8996_mux pwrcl_pmux = {
+	.reg = 0x40,
+	.shift = 0,
+	.width = 2,
+	.pll = &pwrcl_pll.clkr.hw,
+	.clkr.hw.init = &(struct clk_init_data) {
+		.name = "pwrcl_pmux",
+		.parent_names = (const char *[]){
+			"pwrcl_smux",
+			"pwrcl_pll",
+			"pwrcl_pll_acd",
+			"pwrcl_alt_pll",
+		},
+		.num_parents = 4,
+		.ops = &clk_cpu_8996_mux_ops,
+		.flags = CLK_SET_RATE_PARENT | CLK_IS_CRITICAL,
+	},
+};
+
+static struct clk_cpu_8996_mux perfcl_pmux = {
+	.reg = 0x80040,
+	.shift = 0,
+	.width = 2,
+	.pll = &perfcl_pll.clkr.hw,
+	.clkr.hw.init = &(struct clk_init_data) {
+		.name = "perfcl_pmux",
+		.parent_names = (const char *[]){
+			"perfcl_smux",
+			"perfcl_pll",
+			"perfcl_pll_acd",
+			"perfcl_alt_pll",
+		},
+		.num_parents = 4,
+		.ops = &clk_cpu_8996_mux_ops,
+		.flags = CLK_SET_RATE_PARENT | CLK_IS_CRITICAL,
+	},
+};
+
+static const struct regmap_config cpu_msm8996_regmap_config = {
+	.reg_bits		= 32,
+	.reg_stride		= 4,
+	.val_bits		= 32,
+	.max_register		= 0x80210,
+	.fast_io		= true,
+	.val_format_endian	= REGMAP_ENDIAN_LITTLE,
+};
+
+static const struct of_device_id match_table[] = {
+	{ .compatible = "qcom-msm8996-apcc" },
+	{}
+};
+
+struct clk_regmap *clks[] = {
+	/* PLLs */
+	&perfcl_pll.clkr,
+	&pwrcl_pll.clkr,
+	&perfcl_alt_pll.clkr,
+	&pwrcl_alt_pll.clkr,
+	/* MUXs */
+	&perfcl_smux.clkr,
+	&pwrcl_smux.clkr,
+	&perfcl_pmux.clkr,
+	&pwrcl_pmux.clkr,
+};
+
+struct clk_hw_clks {
+	unsigned int num;
+	struct clk_hw *hws[];
+};
+
+static int
+qcom_cpu_clk_msm8996_register_clks(struct device *dev, struct clk_hw_clks *hws,
+				   struct regmap *regmap)
+{
+	int i, ret;
+
+	hws->hws[0] = clk_hw_register_fixed_factor(dev, "perfcl_pll_main",
+						   "perfcl_pll",
+						   CLK_SET_RATE_PARENT, 1, 2);
+	perfcl_smux.pll = hws->hws[0];
+
+	hws->hws[1] = clk_hw_register_fixed_factor(dev, "pwrcl_pll_main",
+						   "pwrcl_pll",
+						   CLK_SET_RATE_PARENT, 1, 2);
+	pwrcl_smux.pll = hws->hws[1];
+
+	hws->num = 2;
+
+	for (i = 0; i < ARRAY_SIZE(clks); i++) {
+		ret = devm_clk_register_regmap(dev, clks[i]);
+		if (ret)
+			return ret;
+	}
+
+	clk_alpha_pll_configure(&perfcl_pll, regmap, &hfpll_config);
+	clk_alpha_pll_configure(&pwrcl_pll, regmap, &hfpll_config);
+	clk_alpha_pll_configure(&perfcl_alt_pll, regmap, &altpll_config);
+	clk_alpha_pll_configure(&pwrcl_alt_pll, regmap, &altpll_config);
+
+	return ret;
+}
+
+static int qcom_cpu_clk_msm8996_driver_probe(struct platform_device *pdev)
+{
+	int ret;
+	void __iomem *base;
+	struct resource *res;
+	struct regmap *regmap_cpu;
+	struct clk_hw_clks *hws;
+	struct clk_hw_onecell_data *data;
+	struct device *dev = &pdev->dev;
+	struct device_node *node = dev->of_node;
+
+	data = devm_kzalloc(dev, sizeof(*data) + 2 * sizeof(struct clk_hw *),
+			    GFP_KERNEL);
+	if (!data)
+		return -ENOMEM;
+
+	hws = devm_kzalloc(dev, sizeof(*hws) + 2 * sizeof(struct clk_hw *),
+			   GFP_KERNEL);
+	if (!hws)
+		return -ENOMEM;
+
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	base = devm_ioremap_resource(dev, res);
+	if (IS_ERR(base))
+		return PTR_ERR(base);
+
+	regmap_cpu = devm_regmap_init_mmio(dev, base,
+					   &cpu_msm8996_regmap_config);
+	if (IS_ERR(regmap_cpu))
+		return PTR_ERR(regmap_cpu);
+
+	ret = qcom_cpu_clk_msm8996_register_clks(dev, hws, regmap_cpu);
+	if (ret)
+		return ret;
+
+	data->hws[0] = &pwrcl_pmux.clkr.hw;
+	data->hws[1] = &perfcl_pmux.clkr.hw;
+
+	data->num = 2;
+
+	platform_set_drvdata(pdev, hws);
+
+	return of_clk_add_hw_provider(node, of_clk_hw_onecell_get, data);
+}
+
+static int qcom_cpu_clk_msm8996_driver_remove(struct platform_device *pdev)
+{
+	int i;
+	struct device *dev = &pdev->dev;
+	struct clk_hw_clks *hws = platform_get_drvdata(pdev);
+
+	for (i = 0; i < hws->num; i++)
+		clk_hw_unregister_fixed_rate(hws->hws[i]);
+
+	of_clk_del_provider(dev->of_node);
+
+	return 0;
+}
+
+static struct platform_driver qcom_cpu_clk_msm8996_driver = {
+	.probe = qcom_cpu_clk_msm8996_driver_probe,
+	.remove = qcom_cpu_clk_msm8996_driver_remove,
+	.driver = {
+		.name = "qcom-msm8996-apcc",
+		.of_match_table = match_table,
+	},
+};
+
+module_platform_driver(qcom_cpu_clk_msm8996_driver);
+
+MODULE_ALIAS("platform:msm8996-apcc");
+MODULE_DESCRIPTION("QCOM MSM8996 CPU clock Driver");
+MODULE_LICENSE("GPL v2");
-- 
1.9.1