[RFC v1 2/3] drivers: nvmem: Add driver for QTI qfprom-efuse support

[Ravi Kumar Bokka]

This patch adds new driver for QTI qfprom-efuse controller. This driver can
access the raw qfprom regions for fuse blowing.

The current existed qfprom driver is only supports for cpufreq, thermal sensors
drivers by read out calibration data, speed bins..etc which is stored
by qfprom efuses.

Signed-off-by: Ravi Kumar Bokka <rbokka@xxxxxxxxxxxxxx>
---
 drivers/nvmem/Kconfig        |  10 +
 drivers/nvmem/Makefile       |   2 +
 drivers/nvmem/qfprom-efuse.c | 476 +++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 488 insertions(+)
 create mode 100644 drivers/nvmem/qfprom-efuse.c

diff --git a/drivers/nvmem/Kconfig b/drivers/nvmem/Kconfig
index d7b7f6d..c9345c5 100644
--- a/drivers/nvmem/Kconfig
+++ b/drivers/nvmem/Kconfig
@@ -121,6 +121,16 @@ config QCOM_QFPROM
 	  This driver can also be built as a module. If so, the module
 	  will be called nvmem_qfprom.
 
+config QTI_QFPROM_EFUSE
+	tristate "QTI_QFPROM_EFUSE Support"
+	depends on HAS_IOMEM
+	help
+	  Say y here to enable QFPROM-Efuse support. This driver provides access
+          QTI qfprom efuse via nvmem interface.
+
+          This driver can also be built as a module. If so, the module
+          will be called nvmem_qfprom-efuse.
+
 config NVMEM_SPMI_SDAM
 	tristate "SPMI SDAM Support"
 	depends on SPMI
diff --git a/drivers/nvmem/Makefile b/drivers/nvmem/Makefile
index a7c3772..1d8fe43 100644
--- a/drivers/nvmem/Makefile
+++ b/drivers/nvmem/Makefile
@@ -27,6 +27,8 @@ obj-$(CONFIG_MTK_EFUSE)		+= nvmem_mtk-efuse.o
 nvmem_mtk-efuse-y		:= mtk-efuse.o
 obj-$(CONFIG_QCOM_QFPROM)	+= nvmem_qfprom.o
 nvmem_qfprom-y			:= qfprom.o
+obj-$(CONFIG_QTI_QFPROM_EFUSE)	+= nvmem_qfprom-efuse.o
+nvmem_qfprom-efuse-y		:= qfprom-efuse.o
 obj-$(CONFIG_NVMEM_SPMI_SDAM)	+= nvmem_qcom-spmi-sdam.o
 nvmem_qcom-spmi-sdam-y		+= qcom-spmi-sdam.o
 obj-$(CONFIG_ROCKCHIP_EFUSE)	+= nvmem_rockchip_efuse.o
diff --git a/drivers/nvmem/qfprom-efuse.c b/drivers/nvmem/qfprom-efuse.c
new file mode 100644
index 0000000..2e3c275
--- /dev/null
+++ b/drivers/nvmem/qfprom-efuse.c
@@ -0,0 +1,476 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (c) 2020, The Linux Foundation. All rights reserved.
+ */
+
+#include <linux/clk.h>
+#include <linux/device.h>
+#include <linux/io.h>
+#include <linux/iopoll.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/mod_devicetable.h>
+#include <linux/nvmem-provider.h>
+#include <linux/of_device.h>
+#include <linux/platform_device.h>
+#include <linux/regulator/consumer.h>
+
+#define QFPROM_BLOW_STATUS_BUSY 0x1
+#define QFPROM_BLOW_STATUS_READY 0x0
+
+/* Blow timer clock frequency in Mhz for 10nm LPe technology */
+#define QFPROM_BLOW_TIMER_OFFSET 0x03c
+#define QFPROM_BLOW_TIMER_RESET_VALUE 0x0
+
+/* Amount of time required to hold charge to blow fuse in micro-seconds */
+#define QFPROM_FUSE_BLOW_POLL_PERIOD 100
+#define QFPROM_BLOW_STATUS_OFFSET 0x048
+
+#define QFPROM_ACCEL_OFFSET 0x044
+
+/**
+ * struct qfprom_efuse_platform_data - structure holding qfprom-efuse
+ * platform data
+ *
+ * @name: qfprom-efuse compatible name
+ * @fuse_blow_time_in_us: Should contain the wait time when doing the fuse blow
+ * @accel_value: Should contain qfprom accel value
+ * @accel_reset_value: The reset value of qfprom accel value
+ * @qfprom_blow_timer_value: The timer value of qfprom when doing efuse blow
+ * @qfprom_blow_reset_freq: The frequency required to set when fuse blowing
+ * is done
+ * @qfprom_blow_set_freq: The frequency required to set when we start the
+ * fuse blowing
+ * @qfprom_max_vol: max voltage required to set fuse blow
+ * @qfprom_min_vol: min voltage required to set fuse blow
+ */
+struct qfprom_efuse_platform_data {
+	const char *name;
+	u8 fuse_blow_time_in_us;
+	u32 accel_value;
+	u32 accel_reset_value;
+	u32 qfprom_blow_timer_value;
+	u32 qfprom_blow_reset_freq;
+	u32 qfprom_blow_set_freq;
+	u32 qfprom_max_vol;
+	u32 qfprom_min_vol;
+};
+
+/**
+ * struct qfprom_efuse_priv - structure holding qfprom-efuse attributes
+ *
+ * @qfpbase: iomapped memory space for qfprom base
+ * @qfpraw: iomapped memory space for qfprom raw fuse region
+ * @qfpmap: iomapped memory space for qfprom fuse blow timer
+
+ * @dev: qfprom device structure
+ * @secclk: clock supply
+ * @vcc: regulator supply
+
+ * @qfpraw_start: qfprom raw fuse start region
+ * @qfpraw_end: qfprom raw fuse end region
+ * @qfprom_efuse_platform_data: qfprom platform data
+ */
+struct qfprom_efuse_priv {
+	void __iomem *qfpbase;
+	void __iomem *qfpraw;
+	void __iomem *qfpmap;
+	struct device *dev;
+	struct clk *secclk;
+	struct regulator *vcc;
+	resource_size_t qfpraw_start;
+	resource_size_t qfpraw_end;
+	struct qfprom_efuse_platform_data efuse;
+};
+
+/*
+ * restore the gcc_sec_ctrl_clk frequency to default value(19.2 MHz)
+ */
+static int qfprom_reset_clock_settings(const struct qfprom_efuse_priv *priv)
+{
+	int ret;
+
+	ret = clk_set_rate(priv->secclk, priv->efuse.qfprom_blow_reset_freq);
+	if (ret) {
+		dev_err(priv->dev, "clk_set_rate() failed to enable secclk\n");
+		return ret;
+	}
+
+	return 0;
+}
+
+/*
+ * set the gcc_sec_ctrl_clk to 4.8 MHz
+ */
+static int qfprom_set_clock_settings(const struct qfprom_efuse_priv *priv)
+{
+	int ret;
+
+	ret = clk_set_rate(priv->secclk, priv->efuse.qfprom_blow_set_freq);
+
+	if (ret) {
+		dev_err(priv->dev, "clk_set_rate() failed to enable secclk\n");
+		return ret;
+	}
+
+	return 0;
+}
+
+/*
+ * set and reset the voltage for 1.8V and OFF(0V) on VDD_QFPROM (LDO11)
+ */
+static int qfprom_set_voltage_settings(const struct qfprom_efuse_priv *priv,
+				       int min_uV, int max_uV)
+{
+	int ret;
+
+	ret = regulator_set_voltage(priv->vcc, min_uV, max_uV);
+
+	if (ret) {
+		dev_err(priv->dev, "regulator_set_voltage() failed!\n");
+		return ret;
+	}
+
+	ret = regulator_enable(priv->vcc);
+	if (ret) {
+		dev_err(priv->dev, "failed to enable regulator\n");
+		return ret;
+	}
+
+	return 0;
+}
+
+/*
+ * resets the value of the blow timer, accel register and the clock
+ * and voltage settings
+ */
+static int qfprom_disable_fuse_blowing(const struct qfprom_efuse_priv *priv)
+{
+	int ret;
+
+	ret = qfprom_set_voltage_settings(priv, 0, priv->efuse.qfprom_max_vol);
+	if (ret) {
+		dev_err(priv->dev, "qfprom_set_voltage_settings failed\n");
+		return ret;
+	}
+
+	ret = qfprom_reset_clock_settings(priv);
+	if (ret) {
+		dev_err(priv->dev, "qfprom_reset_clock_settings failed\n");
+		return ret;
+	}
+
+	writel(QFPROM_BLOW_TIMER_RESET_VALUE, priv->qfpmap +
+		  QFPROM_BLOW_TIMER_OFFSET);
+	writel(priv->efuse.accel_reset_value,
+	       priv->qfpmap + QFPROM_ACCEL_OFFSET);
+
+	return 0;
+}
+
+/*
+ * sets the value of the blow timer, accel register and the clock
+ * and voltage settings
+ */
+static int qfprom_enable_fuse_blowing(const struct qfprom_efuse_priv *priv)
+{
+	int ret;
+
+	ret = qfprom_disable_fuse_blowing(priv);
+	if (ret) {
+		dev_err(priv->dev, "qfprom_disable_fuse_blowing()\n");
+		return ret;
+	}
+
+	writel(priv->efuse.qfprom_blow_timer_value, priv->qfpmap +
+	       QFPROM_BLOW_TIMER_OFFSET);
+	writel(priv->efuse.accel_value, priv->qfpmap + QFPROM_ACCEL_OFFSET);
+
+	ret = qfprom_set_clock_settings(priv);
+	if (ret) {
+		dev_err(priv->dev, "qpfrom_set_clock_settings()\n");
+		return ret;
+	}
+
+	ret = qfprom_set_voltage_settings(priv, priv->efuse.qfprom_min_vol,
+					  priv->efuse.qfprom_max_vol);
+	if (ret) {
+		dev_err(priv->dev, "qfprom_set_voltage_settings()\n");
+		return ret;
+	}
+
+	return 0;
+}
+
+/*
+ * verifying to make sure address being written or read is from qfprom
+ * raw address range
+ */
+bool addr_in_qfprom_range(const struct qfprom_efuse_priv *priv, u32 reg,
+			  size_t bytes)
+{
+	if (((reg + bytes) > reg) && (reg >= priv->qfpraw_start) &&
+	    ((reg + bytes) <= priv->qfpraw_end)) {
+		return 1;
+	}
+
+	return 0;
+}
+
+/*
+ * API for reading from raw qfprom region
+ */
+static int qfprom_efuse_reg_read(void *context, unsigned int reg, void *_val,
+				 size_t bytes)
+{
+	struct qfprom_efuse_priv *priv = context;
+	u32 *value = _val;
+	u32 align_check;
+	int i = 0, words = bytes / 4;
+
+	dev_info(priv->dev,
+		 "reading raw qfprom region offset: 0x%08x of size: %zd\n",
+		 reg, bytes);
+
+	if (bytes % 4 != 0x00) {
+		dev_err(priv->dev,
+			"Bytes: %zd to read should be word align\n",
+			bytes);
+		return -EINVAL;
+	}
+
+	if (!addr_in_qfprom_range(priv, reg, bytes)) {
+		dev_err(priv->dev,
+			"Invalid qfprom raw region offset 0x%08x & bytes %zd\n",
+			reg, bytes);
+		return -EINVAL;
+	}
+
+	align_check = (reg & 0xF);
+
+	if (((align_check & ~3) == align_check) && value != NULL)
+		while (words--)
+			*value++ = readl(priv->qfpbase + reg + (i++ * 4));
+
+	else
+		dev_err(priv->dev,
+			"Invalid input parameter 0x%08x fuse blow address\n",
+			reg);
+
+	return 0;
+}
+
+/*
+ * API for writing to raw qfprom region - fuse blowing
+ * returns success or failure code as per the conditions
+ */
+static int qfprom_efuse_reg_write(void *context, unsigned int reg, void *_val,
+				  size_t bytes)
+{
+	struct qfprom_efuse_priv *priv = context;
+	u32 *value = _val;
+	u32 align_check;
+	u32 blow_status = QFPROM_BLOW_STATUS_BUSY;
+	int ret;
+	int i = 0, words = bytes / 4;
+
+	dev_info(priv->dev,
+		 "writing to raw qfprom region : 0x%08x of size: %zd\n",
+		 reg, bytes);
+
+	if (bytes % 4 != 0x00) {
+		dev_err(priv->dev, "Bytes: %zd should be word align\n", bytes);
+		return -EINVAL;
+	}
+
+	if (!addr_in_qfprom_range(priv, reg, bytes)) {
+		dev_err(priv->dev,
+			"Invalid qfprom raw region offset 0x%08x & bytes %zd\n",
+			 reg, bytes);
+		return -EINVAL;
+	}
+
+	align_check = (reg & 0xF);
+	if (value && ((align_check & ~3) == align_check)) {
+		ret = qfprom_enable_fuse_blowing(priv);
+		if (ret) {
+			dev_err(priv->dev, "qfprom_enable_fuse_blowing");
+			return ret;
+		}
+
+		ret = readl_relaxed_poll_timeout(priv->qfpmap +
+				QFPROM_BLOW_STATUS_OFFSET, blow_status,
+				(blow_status  != QFPROM_BLOW_STATUS_BUSY),
+				QFPROM_FUSE_BLOW_POLL_PERIOD,
+				priv->efuse.fuse_blow_time_in_us);
+
+		if (ret) {
+			dev_err(priv->dev, "Timeout blow status ready\n");
+			return ret;
+		}
+
+		if (blow_status == QFPROM_BLOW_STATUS_READY) {
+			while (words--)
+				writel(*value++,
+				       priv->qfpbase + reg + (i++ * 4));
+
+			ret = readl_relaxed_poll_timeout(priv->qfpmap +
+				QFPROM_BLOW_STATUS_OFFSET, blow_status,
+				(blow_status  != QFPROM_BLOW_STATUS_BUSY),
+				QFPROM_FUSE_BLOW_POLL_PERIOD,
+				priv->efuse.fuse_blow_time_in_us);
+
+			if (ret) {
+				dev_err(priv->dev, "Timeout blow-status ready");
+				return ret;
+			}
+		}
+
+		ret = qfprom_disable_fuse_blowing(priv);
+		if (ret)
+			return ret;
+	} else {
+		dev_err(priv->dev, "Invalid input parameter fuse blow address");
+		return -EINVAL;
+	}
+
+	dev_info(priv->dev, "written successfully raw qfprom region\n");
+
+	return 0;
+}
+
+static int qfprom_efuse_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct resource *qfpbase, *qfpraw, *qfpmap;
+	struct nvmem_device *nvmem;
+	struct nvmem_config *econfig;
+	struct qfprom_efuse_priv *priv;
+	const struct qfprom_efuse_platform_data *drvdata;
+	int ret;
+
+	dev_info(&pdev->dev, "[%s]: Invoked\n", __func__);
+
+	drvdata = of_device_get_match_data(&pdev->dev);
+	if (!drvdata)
+		return -EINVAL;
+
+	priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
+	if (!priv)
+		return -ENOMEM;
+
+	priv->efuse.fuse_blow_time_in_us = drvdata->fuse_blow_time_in_us;
+	priv->efuse.accel_value = drvdata->accel_value;
+	priv->efuse.accel_reset_value = drvdata->accel_reset_value;
+	priv->efuse.qfprom_blow_timer_value = drvdata->qfprom_blow_timer_value;
+	priv->efuse.qfprom_blow_reset_freq = drvdata->qfprom_blow_reset_freq;
+	priv->efuse.qfprom_blow_set_freq = drvdata->qfprom_blow_set_freq;
+	priv->efuse.qfprom_max_vol = drvdata->qfprom_max_vol;
+	priv->efuse.qfprom_min_vol = drvdata->qfprom_min_vol;
+	priv->dev = dev;
+
+	qfpbase = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+
+	priv->qfpbase = devm_ioremap_resource(dev, qfpbase);
+	if (IS_ERR(priv->qfpbase)) {
+		ret = PTR_ERR(priv->qfpbase);
+		goto err;
+	}
+
+	qfpraw = platform_get_resource(pdev, IORESOURCE_MEM, 1);
+
+	priv->qfpraw = devm_ioremap_resource(dev, qfpraw);
+	if (IS_ERR(priv->qfpraw)) {
+		ret = PTR_ERR(priv->qfpraw);
+		goto err;
+	}
+
+	priv->qfpraw_start = qfpraw->start - qfpbase->start;
+	priv->qfpraw_end = qfpraw->end - qfpbase->start;
+
+	qfpmap = platform_get_resource(pdev, IORESOURCE_MEM, 2);
+
+	priv->qfpmap = devm_ioremap_resource(dev, qfpmap);
+	if (IS_ERR(priv->qfpmap)) {
+		ret = PTR_ERR(priv->qfpmap);
+		goto err;
+	}
+
+	priv->vcc = devm_regulator_get(&pdev->dev, "vcc");
+	if (IS_ERR(priv->vcc)) {
+		ret = PTR_ERR(priv->vcc);
+		if (ret == -ENODEV)
+			ret = -EPROBE_DEFER;
+
+		goto err;
+	}
+
+	priv->secclk = devm_clk_get(dev, "secclk");
+	if (IS_ERR(priv->secclk)) {
+		ret = PTR_ERR(priv->secclk);
+		if (ret != -EPROBE_DEFER)
+			dev_err(dev, "secclk error getting : %d\n", ret);
+		goto err;
+	}
+
+	ret = clk_prepare_enable(priv->secclk);
+	if (ret) {
+		dev_err(dev, "clk_prepare_enable() failed\n");
+		goto err;
+	}
+
+	econfig = devm_kzalloc(dev, sizeof(*econfig), GFP_KERNEL);
+	if (!econfig)
+		return -ENOMEM;
+
+	econfig->dev = dev;
+	econfig->name = "qfprom-efuse";
+	econfig->stride = 1;
+	econfig->word_size = 1;
+	econfig->reg_read = qfprom_efuse_reg_read;
+	econfig->reg_write = qfprom_efuse_reg_write;
+	econfig->size = resource_size(qfpraw);
+	econfig->priv = priv;
+
+	nvmem = devm_nvmem_register(dev, econfig);
+
+	return PTR_ERR_OR_ZERO(nvmem);
+
+err:
+	clk_disable_unprepare(priv->secclk);
+	return ret;
+}
+
+static const struct qfprom_efuse_platform_data sc7180_qfp_efuse_data = {
+	.name = "sc7180-qfprom-efuse",
+	.fuse_blow_time_in_us = 10,
+	.accel_value = 0xD10,
+	.accel_reset_value = 0x800,
+	.qfprom_blow_timer_value = 25,
+	.qfprom_blow_reset_freq = 19200000,
+	.qfprom_blow_set_freq = 4800000,
+	.qfprom_max_vol = 1904000,
+	.qfprom_min_vol = 1800000,
+};
+
+static const struct of_device_id qfprom_efuse_of_match[] = {
+	{
+		.compatible = "qcom,sc7180-qfprom-efuse",
+		.data = &sc7180_qfp_efuse_data
+	},
+	{/* sentinel */},
+};
+
+MODULE_DEVICE_TABLE(of, qfprom_efuse_of_match);
+
+static struct platform_driver qfprom_efuse_driver = {
+	.probe = qfprom_efuse_probe,
+	.driver = {
+		.name = "sc7180-qfprom-efuse",
+		.of_match_table = qfprom_efuse_of_match,
+	},
+};
+
+module_platform_driver(qfprom_efuse_driver);
+MODULE_DESCRIPTION("QTI QFPROM Efuse driver");
+MODULE_LICENSE("GPL v2");
-- 
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