Date:   Wed, 14 Nov 2018 14:16:26 +0100
From:   Neil Armstrong <narmstrong@...libre.com>
To:     khilman@...libre.com
Cc:     Neil Armstrong <narmstrong@...libre.com>,
        linux-amlogic@...ts.infradead.org,
        linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org
Subject: [PATCH v2 2/3] soc: amlogic: Add Meson GX Clock Measure driver

The Amlogic Meson GX SoCs embeds a clock measurer IP to measure the internal
clock paths frequencies.
The precision is determined by stepping into the divider until the counter
overflows.
The debugfs slows a pretty summary and each clock can be measured
individually aswell.

The clock table covers all GX SoCs (GXBB, GXL & GXM) even if some clocks
are only present on GXBB or GXM (i.e. wave420l) but the counter returns
0 when the clocks are invalid.

Signed-off-by: Neil Armstrong <narmstrong@...libre.com>
---
 drivers/soc/amlogic/Kconfig                |   8 +
 drivers/soc/amlogic/Makefile               |   1 +
 drivers/soc/amlogic/meson-gx-clk-measure.c | 293 +++++++++++++++++++++
 3 files changed, 302 insertions(+)
 create mode 100644 drivers/soc/amlogic/meson-gx-clk-measure.c

diff --git a/drivers/soc/amlogic/Kconfig b/drivers/soc/amlogic/Kconfig
index 2f282b472912..155868830773 100644
--- a/drivers/soc/amlogic/Kconfig
+++ b/drivers/soc/amlogic/Kconfig
@@ -7,6 +7,14 @@ config MESON_CANVAS
 	help
 	  Say yes to support the canvas IP for Amlogic SoCs.
 
+config MESON_GX_CLK_MEASURE
+	bool "Amlogic Meson GX SoC Clock Measure driver"
+	depends on ARCH_MESON || COMPILE_TEST
+	default ARCH_MESON
+	help
+	  Say yes to support of Measuring a set of internal SoC clocks
+	  from the debugfs interface.
+
 config MESON_GX_SOCINFO
 	bool "Amlogic Meson GX SoC Information driver"
 	depends on ARCH_MESON || COMPILE_TEST
diff --git a/drivers/soc/amlogic/Makefile b/drivers/soc/amlogic/Makefile
index 0ab16d35ac36..2cc0f9c2f715 100644
--- a/drivers/soc/amlogic/Makefile
+++ b/drivers/soc/amlogic/Makefile
@@ -1,4 +1,5 @@
 obj-$(CONFIG_MESON_CANVAS) += meson-canvas.o
+obj-$(CONFIG_MESON_GX_CLK_MEASURE) += meson-gx-clk-measure.o
 obj-$(CONFIG_MESON_GX_SOCINFO) += meson-gx-socinfo.o
 obj-$(CONFIG_MESON_GX_PM_DOMAINS) += meson-gx-pwrc-vpu.o
 obj-$(CONFIG_MESON_MX_SOCINFO) += meson-mx-socinfo.o
diff --git a/drivers/soc/amlogic/meson-gx-clk-measure.c b/drivers/soc/amlogic/meson-gx-clk-measure.c
new file mode 100644
index 000000000000..da1a0001cef9
--- /dev/null
+++ b/drivers/soc/amlogic/meson-gx-clk-measure.c
@@ -0,0 +1,293 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Copyright (c) 2017 BayLibre, SAS
+ * Author: Neil Armstrong <narmstrong@...libre.com>
+ */
+
+#include <linux/of_address.h>
+#include <linux/platform_device.h>
+#include <linux/bitfield.h>
+#include <linux/seq_file.h>
+#include <linux/debugfs.h>
+#include <linux/regmap.h>
+
+#define MSR_CLK_DUTY		0x0
+#define MSR_CLK_REG0		0x4
+#define MSR_CLK_REG1		0x8
+#define MSR_CLK_REG2		0xc
+
+#define MSR_CLK_DIV		GENMASK(15, 0)
+#define MSR_ENABLE		BIT(16)
+#define MSR_CONT		BIT(17) /* continuous measurement */
+#define MSR_INTR		BIT(18) /* interrupts */
+#define MSR_RUN			BIT(19)
+#define MSR_CLK_SRC		GENMASK(26, 20)
+#define MSR_BUSY		BIT(31)
+
+#define MSR_VAL_MASK		GENMASK(15, 0)
+
+#define DIV_MIN			32
+#define DIV_STEP		32
+#define DIV_MAX			640
+
+#define CLK_MSR_MAX		128
+
+struct meson_gx_msr_id {
+	struct meson_gx_msr *priv;
+	unsigned int id;
+	const char *name;
+};
+
+struct meson_gx_msr {
+	struct regmap *regmap;
+	struct meson_gx_msr_id msr_table[CLK_MSR_MAX];
+};
+
+#define CLK_MSR_ID(__id, __name) \
+	[__id] = {.id = __id, .name = __name,}
+
+static struct meson_gx_msr_id clk_msr_gx[CLK_MSR_MAX] = {
+	CLK_MSR_ID(0, "ring_osc_out_ee_0"),
+	CLK_MSR_ID(1, "ring_osc_out_ee_1"),
+	CLK_MSR_ID(2, "ring_osc_out_ee_2"),
+	CLK_MSR_ID(3, "a53_ring_osc"),
+	CLK_MSR_ID(4, "gp0_pll"),
+	CLK_MSR_ID(6, "enci"),
+	CLK_MSR_ID(7, "clk81"),
+	CLK_MSR_ID(8, "encp"),
+	CLK_MSR_ID(9, "encl"),
+	CLK_MSR_ID(10, "vdac"),
+	CLK_MSR_ID(11, "rgmii_tx"),
+	CLK_MSR_ID(12, "pdm"),
+	CLK_MSR_ID(13, "amclk"),
+	CLK_MSR_ID(14, "fec_0"),
+	CLK_MSR_ID(15, "fec_1"),
+	CLK_MSR_ID(16, "fec_2"),
+	CLK_MSR_ID(17, "sys_pll_div16"),
+	CLK_MSR_ID(18, "sys_cpu_div16"),
+	CLK_MSR_ID(19, "hdmitx_sys"),
+	CLK_MSR_ID(20, "rtc_osc_out"),
+	CLK_MSR_ID(21, "i2s_in_src0"),
+	CLK_MSR_ID(22, "eth_phy_ref"),
+	CLK_MSR_ID(23, "hdmi_todig"),
+	CLK_MSR_ID(26, "sc_int"),
+	CLK_MSR_ID(28, "sar_adc"),
+	CLK_MSR_ID(31, "mpll_test_out"),
+	CLK_MSR_ID(32, "vdec"),
+	CLK_MSR_ID(35, "mali"),
+	CLK_MSR_ID(36, "hdmi_tx_pixel"),
+	CLK_MSR_ID(37, "i958"),
+	CLK_MSR_ID(38, "vdin_meas"),
+	CLK_MSR_ID(39, "pcm_sclk"),
+	CLK_MSR_ID(40, "pcm_mclk"),
+	CLK_MSR_ID(41, "eth_rx_or_rmii"),
+	CLK_MSR_ID(42, "mp0_out"),
+	CLK_MSR_ID(43, "fclk_div5"),
+	CLK_MSR_ID(44, "pwm_b"),
+	CLK_MSR_ID(45, "pwm_a"),
+	CLK_MSR_ID(46, "vpu"),
+	CLK_MSR_ID(47, "ddr_dpll_pt"),
+	CLK_MSR_ID(48, "mp1_out"),
+	CLK_MSR_ID(49, "mp2_out"),
+	CLK_MSR_ID(50, "mp3_out"),
+	CLK_MSR_ID(51, "nand_core"),
+	CLK_MSR_ID(52, "sd_emmc_b"),
+	CLK_MSR_ID(53, "sd_emmc_a"),
+	CLK_MSR_ID(55, "vid_pll_div_out"),
+	CLK_MSR_ID(56, "cci"),
+	CLK_MSR_ID(57, "wave420l_c"),
+	CLK_MSR_ID(58, "wave420l_b"),
+	CLK_MSR_ID(59, "hcodec"),
+	CLK_MSR_ID(60, "alt_32k"),
+	CLK_MSR_ID(61, "gpio_msr"),
+	CLK_MSR_ID(62, "hevc"),
+	CLK_MSR_ID(66, "vid_lock"),
+	CLK_MSR_ID(70, "pwm_f"),
+	CLK_MSR_ID(71, "pwm_e"),
+	CLK_MSR_ID(72, "pwm_d"),
+	CLK_MSR_ID(73, "pwm_c"),
+	CLK_MSR_ID(75, "aoclkx2_int"),
+	CLK_MSR_ID(76, "aoclk_int"),
+	CLK_MSR_ID(77, "rng_ring_osc_0"),
+	CLK_MSR_ID(78, "rng_ring_osc_1"),
+	CLK_MSR_ID(79, "rng_ring_osc_2"),
+	CLK_MSR_ID(80, "rng_ring_osc_3"),
+	CLK_MSR_ID(81, "vapb"),
+	CLK_MSR_ID(82, "ge2d"),
+};
+
+static int meson_gx_measure_id(struct meson_gx_msr_id *clk_msr_id,
+			       unsigned int divider)
+{
+	struct meson_gx_msr *priv = clk_msr_id->priv;
+	unsigned int val;
+	int ret;
+
+	regmap_write(priv->regmap, MSR_CLK_REG0, 0);
+
+	/* Set measurement divider */
+	regmap_update_bits(priv->regmap, MSR_CLK_REG0, MSR_CLK_DIV,
+			   FIELD_PREP(MSR_CLK_DIV, divider - 1));
+
+	/* Set ID */
+	regmap_update_bits(priv->regmap, MSR_CLK_REG0, MSR_CLK_SRC,
+			   FIELD_PREP(MSR_CLK_SRC, clk_msr_id->id));
+
+	/* Enable & Start */
+	regmap_update_bits(priv->regmap, MSR_CLK_REG0,
+			   MSR_RUN | MSR_ENABLE,
+			   MSR_RUN | MSR_ENABLE);
+
+	ret = regmap_read_poll_timeout(priv->regmap, MSR_CLK_REG0,
+				       val, !(val & MSR_BUSY), 10, 10000);
+	if (ret)
+		return ret;
+
+	/* Disable */
+	regmap_update_bits(priv->regmap, MSR_CLK_REG0, MSR_ENABLE, 0);
+
+	/* Get the value in multiple of gate time counts */
+	regmap_read(priv->regmap, MSR_CLK_REG2, &val);
+
+	if (val >= MSR_VAL_MASK)
+		return -EINVAL;
+
+	return DIV_ROUND_CLOSEST((val & MSR_VAL_MASK) * 1000000,
+				 divider);
+}
+
+static int meson_gx_measure_best_id(struct meson_gx_msr_id *clk_msr_id,
+				    unsigned int *precision)
+{
+	unsigned int divider = DIV_MAX;
+	int ret;
+
+	/* Start from max divider and down to min divider */
+	do {
+		ret = meson_gx_measure_id(clk_msr_id, divider);
+		if (ret >= 0)
+			*precision = (2 * 1000000) / divider;
+		else
+			divider -= DIV_STEP;
+	} while (divider >= DIV_MIN && ret == -EINVAL);
+
+	return ret;
+}
+
+static int clk_msr_show(struct seq_file *s, void *data)
+{
+	struct meson_gx_msr_id *clk_msr_id = s->private;
+	unsigned int precision = 0;
+	int val;
+
+	val = meson_gx_measure_best_id(clk_msr_id, &precision);
+	if (val < 0)
+		return val;
+
+	seq_printf(s, "%d\t+/-%dHz\n", val, precision);
+
+	return 0;
+}
+DEFINE_SHOW_ATTRIBUTE(clk_msr);
+
+static int clk_msr_summary_show(struct seq_file *s, void *data)
+{
+	struct meson_gx_msr_id *msr_table = s->private;
+	unsigned int precision = 0;
+	int val, i;
+
+	seq_puts(s, "  clock                     rate    precision\n");
+	seq_puts(s, "---------------------------------------------\n");
+
+	for (i = 0 ; i < CLK_MSR_MAX ; ++i) {
+		if (!msr_table[i].name)
+			continue;
+
+		val = meson_gx_measure_best_id(&msr_table[i], &precision);
+		if (val < 0)
+			return val;
+
+		seq_printf(s, " %-20s %10d    +/-%dHz\n",
+			   msr_table[i].name, val, precision);
+	}
+
+	return 0;
+}
+DEFINE_SHOW_ATTRIBUTE(clk_msr_summary);
+
+static const struct regmap_config clk_msr_regmap_config = {
+	.reg_bits = 32,
+	.val_bits = 32,
+	.reg_stride = 4,
+	.max_register = MSR_CLK_REG2,
+};
+
+static int meson_gx_msr_probe(struct platform_device *pdev)
+{
+	const struct meson_gx_msr_id *match_data;
+	struct meson_gx_msr *priv;
+	struct resource *res;
+	struct dentry *root, *clks;
+	void __iomem *base;
+	int i;
+
+	priv = devm_kzalloc(&pdev->dev, sizeof(struct meson_gx_msr),
+			    GFP_KERNEL);
+	if (!priv)
+		return -ENOMEM;
+
+	match_data = device_get_match_data(&pdev->dev);
+	if (!match_data) {
+		dev_err(&pdev->dev, "failed to get match data\n");
+		return -ENODEV;
+	}
+
+	memcpy(priv->msr_table, match_data, sizeof(priv->msr_table));
+
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	base = devm_ioremap_resource(&pdev->dev, res);
+	if (IS_ERR(base)) {
+		dev_err(&pdev->dev, "io resource mapping failed\n");
+		return PTR_ERR(base);
+	}
+
+	priv->regmap = devm_regmap_init_mmio(&pdev->dev, base,
+					      &clk_msr_regmap_config);
+	if (IS_ERR(priv->regmap))
+		return PTR_ERR(priv->regmap);
+
+	root = debugfs_create_dir("meson-clk-msr", NULL);
+	clks = debugfs_create_dir("clks", root);
+
+	debugfs_create_file("measure_summary", 0444, root,
+			    priv->msr_table, &clk_msr_summary_fops);
+
+	for (i = 0 ; i < CLK_MSR_MAX ; ++i) {
+		if (!priv->msr_table[i].name)
+			continue;
+
+		priv->msr_table[i].priv = priv;
+
+		debugfs_create_file(priv->msr_table[i].name, 0444, clks,
+				    &priv->msr_table[i], &clk_msr_fops);
+	}
+
+	return 0;
+}
+
+static const struct of_device_id meson_gx_msr_match_table[] = {
+	{
+		.compatible = "amlogic,meson-gx-clk-measure",
+		.data = (void *)clk_msr_gx,
+	},
+	{ /* sentinel */ }
+};
+
+static struct platform_driver meson_gx_msr_driver = {
+	.probe	= meson_gx_msr_probe,
+	.driver = {
+		.name		= "meson_gx_msr",
+		.of_match_table	= meson_gx_msr_match_table,
+	},
+};
+builtin_platform_driver(meson_gx_msr_driver);
-- 
2.19.1

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