diff options
Diffstat (limited to 'drivers/nvmem/qfprom.c')
| -rw-r--r-- | drivers/nvmem/qfprom.c | 392 |
1 files changed, 392 insertions, 0 deletions
diff --git a/drivers/nvmem/qfprom.c b/drivers/nvmem/qfprom.c new file mode 100644 index 000000000..8ef772ccf --- /dev/null +++ b/drivers/nvmem/qfprom.c @@ -0,0 +1,392 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * 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/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 *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; + + writel(old->timer_val, priv->qfpconf + QFPROM_BLOW_TIMER_OFFSET); + writel(old->accel_val, priv->qfpconf + QFPROM_ACCEL_OFFSET); + + /* + * This may be a shared rail and may be able to run at a lower rate + * when we're not blowing fuses. At the moment, the regulator framework + * applies voltage constraints even on disabled rails, so remove our + * constraints and allow the rail to be adjusted by other users. + */ + ret = regulator_set_voltage(priv->vcc, 0, INT_MAX); + if (ret) + dev_warn(priv->dev, "Failed to set 0 voltage (ignoring)\n"); + + 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); +} + +/** + * 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; + } + + /* + * Hardware requires 1.8V min for fuse blowing; this may be + * a rail shared do don't specify a max--regulator constraints + * will handle. + */ + ret = regulator_set_voltage(priv->vcc, 1800000, INT_MAX); + if (ret) { + dev_err(priv->dev, "Failed to set 1.8 voltage\n"); + goto err_clk_rate_set; + } + + 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(base + reg + i++); + + return 0; +} + +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->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); +} + +static const struct of_device_id qfprom_of_match[] = { + { .compatible = "qcom,qfprom",}, + {/* sentinel */}, +}; +MODULE_DEVICE_TABLE(of, qfprom_of_match); + +static struct platform_driver qfprom_driver = { + .probe = qfprom_probe, + .driver = { + .name = "qcom,qfprom", + .of_match_table = qfprom_of_match, + }, +}; +module_platform_driver(qfprom_driver); +MODULE_AUTHOR("Srinivas Kandagatla <srinivas.kandagatla@linaro.org>"); +MODULE_DESCRIPTION("Qualcomm QFPROM driver"); +MODULE_LICENSE("GPL v2"); |