nvmem: qfprom: Add fuse blowing support
authorRavi Kumar Bokka <rbokka@codeaurora.org>
Wed, 22 Jul 2020 10:07:02 +0000 (11:07 +0100)
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Wed, 29 Jul 2020 15:12:09 +0000 (17:12 +0200)
This patch adds support for blowing fuses to the qfprom driver if the
required properties are defined in the device tree.

[Srini: Fixed merge conflict with AUTO ID]
Signed-off-by: Ravi Kumar Bokka <rbokka@codeaurora.org>
Signed-off-by: Douglas Anderson <dianders@chromium.org>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Link: https://lore.kernel.org/r/20200722100705.7772-12-srinivas.kandagatla@linaro.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
drivers/nvmem/qfprom.c

index 8b425f8..5e9e60e 100644 (file)
  * Copyright (C) 2015 Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
  */
 
+#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/io.h>
 #include <linux/nvmem-provider.h>
 #include <linux/platform_device.h>
+#include <linux/regulator/consumer.h>
+
+/* Blow timer clock frequency in Mhz */
+#define QFPROM_BLOW_TIMER_OFFSET 0x03c
+
+/* Amount of time required to hold charge to blow fuse in micro-seconds */
+#define QFPROM_FUSE_BLOW_POLL_US       100
+#define QFPROM_FUSE_BLOW_TIMEOUT_US    1000
+
+#define QFPROM_BLOW_STATUS_OFFSET      0x048
+#define QFPROM_BLOW_STATUS_BUSY                0x1
+#define QFPROM_BLOW_STATUS_READY       0x0
+
+#define QFPROM_ACCEL_OFFSET            0x044
+
+#define QFPROM_VERSION_OFFSET          0x0
+#define QFPROM_MAJOR_VERSION_SHIFT     28
+#define QFPROM_MAJOR_VERSION_MASK      GENMASK(31, QFPROM_MAJOR_VERSION_SHIFT)
+#define QFPROM_MINOR_VERSION_SHIFT     16
+#define QFPROM_MINOR_VERSION_MASK      GENMASK(27, QFPROM_MINOR_VERSION_SHIFT)
+
+static bool read_raw_data;
+module_param(read_raw_data, bool, 0644);
+MODULE_PARM_DESC(read_raw_data, "Read raw instead of corrected data");
 
+/**
+ * struct qfprom_soc_data - config that varies from SoC to SoC.
+ *
+ * @accel_value:             Should contain qfprom accel value.
+ * @qfprom_blow_timer_value: The timer value of qfprom when doing efuse blow.
+ * @qfprom_blow_set_freq:    The frequency required to set when we start the
+ *                           fuse blowing.
+ */
+struct qfprom_soc_data {
+       u32 accel_value;
+       u32 qfprom_blow_timer_value;
+       u32 qfprom_blow_set_freq;
+};
+
+/**
+ * struct qfprom_priv - structure holding qfprom attributes
+ *
+ * @qfpraw:       iomapped memory space for qfprom-efuse raw address space.
+ * @qfpconf:      iomapped memory space for qfprom-efuse configuration address
+ *                space.
+ * @qfpcorrected: iomapped memory space for qfprom corrected address space.
+ * @qfpsecurity:  iomapped memory space for qfprom security control space.
+ * @dev:          qfprom device structure.
+ * @secclk:       Clock supply.
+ * @vcc:          Regulator supply.
+ * @soc_data:     Data that for things that varies from SoC to SoC.
+ */
 struct qfprom_priv {
-       void __iomem *base;
+       void __iomem *qfpraw;
+       void __iomem *qfpconf;
+       void __iomem *qfpcorrected;
+       void __iomem *qfpsecurity;
+       struct device *dev;
+       struct clk *secclk;
+       struct regulator *vcc;
+       const struct qfprom_soc_data *soc_data;
+};
+
+/**
+ * struct qfprom_touched_values - saved values to restore after blowing
+ *
+ * @clk_rate: The rate the clock was at before blowing.
+ * @accel_val: The value of the accel reg before blowing.
+ * @timer_val: The value of the timer before blowing.
+ */
+struct qfprom_touched_values {
+       unsigned long clk_rate;
+       u32 accel_val;
+       u32 timer_val;
 };
 
+/**
+ * qfprom_disable_fuse_blowing() - Undo enabling of fuse blowing.
+ * @priv: Our driver data.
+ * @old:  The data that was stashed from before fuse blowing.
+ *
+ * Resets the value of the blow timer, accel register and the clock
+ * and voltage settings.
+ *
+ * Prints messages if there are errors but doesn't return an error code
+ * since there's not much we can do upon failure.
+ */
+static void qfprom_disable_fuse_blowing(const struct qfprom_priv *priv,
+                                       const struct qfprom_touched_values *old)
+{
+       int ret;
+
+       ret = regulator_disable(priv->vcc);
+       if (ret)
+               dev_warn(priv->dev, "Failed to disable regulator (ignoring)\n");
+
+       ret = clk_set_rate(priv->secclk, old->clk_rate);
+       if (ret)
+               dev_warn(priv->dev,
+                        "Failed to set clock rate for disable (ignoring)\n");
+
+       clk_disable_unprepare(priv->secclk);
+
+       writel(old->timer_val, priv->qfpconf + QFPROM_BLOW_TIMER_OFFSET);
+       writel(old->accel_val, priv->qfpconf + QFPROM_ACCEL_OFFSET);
+}
+
+/**
+ * qfprom_enable_fuse_blowing() - Enable fuse blowing.
+ * @priv: Our driver data.
+ * @old:  We'll stash stuff here to use when disabling.
+ *
+ * Sets the value of the blow timer, accel register and the clock
+ * and voltage settings.
+ *
+ * Prints messages if there are errors so caller doesn't need to.
+ *
+ * Return: 0 or -err.
+ */
+static int qfprom_enable_fuse_blowing(const struct qfprom_priv *priv,
+                                     struct qfprom_touched_values *old)
+{
+       int ret;
+
+       ret = clk_prepare_enable(priv->secclk);
+       if (ret) {
+               dev_err(priv->dev, "Failed to enable clock\n");
+               return ret;
+       }
+
+       old->clk_rate = clk_get_rate(priv->secclk);
+       ret = clk_set_rate(priv->secclk, priv->soc_data->qfprom_blow_set_freq);
+       if (ret) {
+               dev_err(priv->dev, "Failed to set clock rate for enable\n");
+               goto err_clk_prepared;
+       }
+
+       ret = regulator_enable(priv->vcc);
+       if (ret) {
+               dev_err(priv->dev, "Failed to enable regulator\n");
+               goto err_clk_rate_set;
+       }
+
+       old->timer_val = readl(priv->qfpconf + QFPROM_BLOW_TIMER_OFFSET);
+       old->accel_val = readl(priv->qfpconf + QFPROM_ACCEL_OFFSET);
+       writel(priv->soc_data->qfprom_blow_timer_value,
+              priv->qfpconf + QFPROM_BLOW_TIMER_OFFSET);
+       writel(priv->soc_data->accel_value,
+              priv->qfpconf + QFPROM_ACCEL_OFFSET);
+
+       return 0;
+
+err_clk_rate_set:
+       clk_set_rate(priv->secclk, old->clk_rate);
+err_clk_prepared:
+       clk_disable_unprepare(priv->secclk);
+       return ret;
+}
+
+/**
+ * qfprom_efuse_reg_write() - Write to fuses.
+ * @context: Our driver data.
+ * @reg:     The offset to write at.
+ * @_val:    Pointer to data to write.
+ * @bytes:   The number of bytes to write.
+ *
+ * Writes to fuses.  WARNING: THIS IS PERMANENT.
+ *
+ * Return: 0 or -err.
+ */
+static int qfprom_reg_write(void *context, unsigned int reg, void *_val,
+                           size_t bytes)
+{
+       struct qfprom_priv *priv = context;
+       struct qfprom_touched_values old;
+       int words = bytes / 4;
+       u32 *value = _val;
+       u32 blow_status;
+       int ret;
+       int i;
+
+       dev_dbg(priv->dev,
+               "Writing to raw qfprom region : %#010x of size: %zu\n",
+               reg, bytes);
+
+       /*
+        * The hardware only allows us to write word at a time, but we can
+        * read byte at a time.  Until the nvmem framework allows a separate
+        * word_size and stride for reading vs. writing, we'll enforce here.
+        */
+       if (bytes % 4) {
+               dev_err(priv->dev,
+                       "%zu is not an integral number of words\n", bytes);
+               return -EINVAL;
+       }
+       if (reg % 4) {
+               dev_err(priv->dev,
+                       "Invalid offset: %#x.  Must be word aligned\n", reg);
+               return -EINVAL;
+       }
+
+       ret = qfprom_enable_fuse_blowing(priv, &old);
+       if (ret)
+               return ret;
+
+       ret = readl_relaxed_poll_timeout(
+               priv->qfpconf + QFPROM_BLOW_STATUS_OFFSET,
+               blow_status, blow_status == QFPROM_BLOW_STATUS_READY,
+               QFPROM_FUSE_BLOW_POLL_US, QFPROM_FUSE_BLOW_TIMEOUT_US);
+
+       if (ret) {
+               dev_err(priv->dev,
+                       "Timeout waiting for initial ready; aborting.\n");
+               goto exit_enabled_fuse_blowing;
+       }
+
+       for (i = 0; i < words; i++)
+               writel(value[i], priv->qfpraw + reg + (i * 4));
+
+       ret = readl_relaxed_poll_timeout(
+               priv->qfpconf + QFPROM_BLOW_STATUS_OFFSET,
+               blow_status, blow_status == QFPROM_BLOW_STATUS_READY,
+               QFPROM_FUSE_BLOW_POLL_US, QFPROM_FUSE_BLOW_TIMEOUT_US);
+
+       /* Give an error, but not much we can do in this case */
+       if (ret)
+               dev_err(priv->dev, "Timeout waiting for finish.\n");
+
+exit_enabled_fuse_blowing:
+       qfprom_disable_fuse_blowing(priv, &old);
+
+       return ret;
+}
+
 static int qfprom_reg_read(void *context,
                        unsigned int reg, void *_val, size_t bytes)
 {
        struct qfprom_priv *priv = context;
        u8 *val = _val;
        int i = 0, words = bytes;
+       void __iomem *base = priv->qfpcorrected;
+
+       if (read_raw_data && priv->qfpraw)
+               base = priv->qfpraw;
 
        while (words--)
-               *val++ = readb(priv->base + reg + i++);
+               *val++ = readb(base + reg + i++);
 
        return 0;
 }
 
-static struct nvmem_config econfig = {
-       .name = "qfprom",
-       .stride = 1,
-       .word_size = 1,
-       .id = NVMEM_DEVID_AUTO,
-       .reg_read = qfprom_reg_read,
+static const struct qfprom_soc_data qfprom_7_8_data = {
+       .accel_value = 0xD10,
+       .qfprom_blow_timer_value = 25,
+       .qfprom_blow_set_freq = 4800000,
 };
 
 static int qfprom_probe(struct platform_device *pdev)
 {
+       struct nvmem_config econfig = {
+               .name = "qfprom",
+               .stride = 1,
+               .word_size = 1,
+               .id = NVMEM_DEVID_AUTO,
+               .reg_read = qfprom_reg_read,
+       };
        struct device *dev = &pdev->dev;
        struct resource *res;
        struct nvmem_device *nvmem;
        struct qfprom_priv *priv;
+       int ret;
 
        priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
        if (!priv)
                return -ENOMEM;
 
+       /* The corrected section is always provided */
        res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
-       priv->base = devm_ioremap_resource(dev, res);
-       if (IS_ERR(priv->base))
-               return PTR_ERR(priv->base);
+       priv->qfpcorrected = devm_ioremap_resource(dev, res);
+       if (IS_ERR(priv->qfpcorrected))
+               return PTR_ERR(priv->qfpcorrected);
 
        econfig.size = resource_size(res);
        econfig.dev = dev;
        econfig.priv = priv;
 
+       priv->dev = dev;
+
+       /*
+        * If more than one region is provided then the OS has the ability
+        * to write.
+        */
+       res = platform_get_resource(pdev, IORESOURCE_MEM, 1);
+       if (res) {
+               u32 version;
+               int major_version, minor_version;
+
+               priv->qfpraw = devm_ioremap_resource(dev, res);
+               if (IS_ERR(priv->qfpraw))
+                       return PTR_ERR(priv->qfpraw);
+               res = platform_get_resource(pdev, IORESOURCE_MEM, 2);
+               priv->qfpconf = devm_ioremap_resource(dev, res);
+               if (IS_ERR(priv->qfpconf))
+                       return PTR_ERR(priv->qfpconf);
+               res = platform_get_resource(pdev, IORESOURCE_MEM, 3);
+               priv->qfpsecurity = devm_ioremap_resource(dev, res);
+               if (IS_ERR(priv->qfpsecurity))
+                       return PTR_ERR(priv->qfpsecurity);
+
+               version = readl(priv->qfpsecurity + QFPROM_VERSION_OFFSET);
+               major_version = (version & QFPROM_MAJOR_VERSION_MASK) >>
+                               QFPROM_MAJOR_VERSION_SHIFT;
+               minor_version = (version & QFPROM_MINOR_VERSION_MASK) >>
+                               QFPROM_MINOR_VERSION_SHIFT;
+
+               if (major_version == 7 && minor_version == 8)
+                       priv->soc_data = &qfprom_7_8_data;
+
+               priv->vcc = devm_regulator_get(&pdev->dev, "vcc");
+               if (IS_ERR(priv->vcc))
+                       return PTR_ERR(priv->vcc);
+
+               priv->secclk = devm_clk_get(dev, "core");
+               if (IS_ERR(priv->secclk)) {
+                       ret = PTR_ERR(priv->secclk);
+                       if (ret != -EPROBE_DEFER)
+                               dev_err(dev, "Error getting clock: %d\n", ret);
+                       return ret;
+               }
+
+               /* Only enable writing if we have SoC data. */
+               if (priv->soc_data)
+                       econfig.reg_write = qfprom_reg_write;
+       }
+
        nvmem = devm_nvmem_register(dev, &econfig);
 
        return PTR_ERR_OR_ZERO(nvmem);