nvmem: Add R-Car E-FUSE driver

R-Car Gen4 SoCs contain fuses indicating hardware support or hardware
(e.g. tuning) parameters.  Add a driver to access the state of the
fuses.  This supports two types of hardware fuse providers:
  1. E-FUSE non-volatile memory accessible through the Pin Function
     Controller on R-Car V3U and S4-8,
  2. E-FUSE non-volatile memory accessible through OTP_MEM on R-Car V4H
     and V4M.

The state of the cells can be read using the NVMEM framework, either
from kernel space (e.g. by the Renesas UFSHCD driver), or from
userspace.

Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Reviewed-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Link: https://lore.kernel.org/r/20241030140315.40562-3-srinivas.kandagatla@linaro.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/MAINTAINERS b/MAINTAINERS
index fb10bd3fa63b42ca5328e94f5fc5e8ab59682faa..a1e26112af1c30b5e6aa8c0f7c1bed2942a2ab89 100644 (file)
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -2930,6 +2930,7 @@ F:        arch/arm/include/debug/renesas-scif.S
 F:     arch/arm/mach-shmobile/
 F:     arch/arm64/boot/dts/renesas/
 F:     arch/riscv/boot/dts/renesas/
+F:     drivers/nvmem/rcar-efuse.c
 F:     drivers/pmdomain/renesas/
 F:     drivers/soc/renesas/
 F:     include/linux/soc/renesas/

diff --git a/drivers/nvmem/Kconfig b/drivers/nvmem/Kconfig
index d2c384f58028dce4e8fd23b273b66c4f97082746..8671b7c974b933e147154bb40b5d41b5730518d2 100644 (file)
--- a/drivers/nvmem/Kconfig
+++ b/drivers/nvmem/Kconfig
@@ -246,6 +246,17 @@ config NVMEM_RAVE_SP_EEPROM
        help
          Say y here to enable Rave SP EEPROM support.
 
+config NVMEM_RCAR_EFUSE
+       tristate "Renesas R-Car Gen4 E-FUSE support"
+       depends on (ARCH_RENESAS && ARM64) || COMPILE_TEST
+       depends on NVMEM
+       help
+         Enable support for reading the fuses in the E-FUSE or OTP
+         non-volatile memory block on Renesas R-Car Gen4 SoCs.
+
+         This driver can also be built as a module. If so, the module
+         will be called nvmem-rcar-efuse.
+
 config NVMEM_RMEM
        tristate "Reserved Memory Based Driver Support"
        depends on HAS_IOMEM

diff --git a/drivers/nvmem/Makefile b/drivers/nvmem/Makefile
index cdd01fbf1313b58c61f71066997e2f0fadaae823..5b77bbb6488bf89bfb305750a1cbf4a6731a0a58 100644 (file)
--- a/drivers/nvmem/Makefile
+++ b/drivers/nvmem/Makefile
@@ -52,6 +52,8 @@ obj-$(CONFIG_NVMEM_QCOM_SEC_QFPROM)   += nvmem_sec_qfprom.o
 nvmem_sec_qfprom-y                     := sec-qfprom.o
 obj-$(CONFIG_NVMEM_RAVE_SP_EEPROM)     += nvmem-rave-sp-eeprom.o
 nvmem-rave-sp-eeprom-y                 := rave-sp-eeprom.o
+obj-$(CONFIG_NVMEM_RCAR_EFUSE)         += nvmem-rcar-efuse.o
+nvmem-rcar-efuse-y                     := rcar-efuse.o
 obj-$(CONFIG_NVMEM_RMEM)               += nvmem-rmem.o
 nvmem-rmem-y                           := rmem.o
 obj-$(CONFIG_NVMEM_ROCKCHIP_EFUSE)     += nvmem_rockchip_efuse.o

diff --git a/drivers/nvmem/rcar-efuse.c b/drivers/nvmem/rcar-efuse.c
new file mode 100644 (file)
index 0000000..f24bdb9
--- /dev/null
+++ b/drivers/nvmem/rcar-efuse.c
@@ -0,0 +1,142 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Renesas R-Car E-FUSE/OTP Driver
+ *
+ * Copyright (C) 2024 Glider bv
+ */
+
+#include <linux/device.h>
+#include <linux/export.h>
+#include <linux/io.h>
+#include <linux/mod_devicetable.h>
+#include <linux/nvmem-provider.h>
+#include <linux/platform_device.h>
+#include <linux/pm_runtime.h>
+#include <linux/property.h>
+
+struct rcar_fuse {
+       struct nvmem_keepout keepouts[2];
+       struct nvmem_device *nvmem;
+       struct device *dev;
+       void __iomem *base;
+};
+
+struct rcar_fuse_data {
+       unsigned int bank;      /* 0: PFC + E-FUSE, 1: OPT_MEM + E-FUSE */
+       unsigned int start;     /* inclusive */
+       unsigned int end;       /* exclusive */
+};
+
+static int rcar_fuse_reg_read(void *priv, unsigned int offset, void *val,
+                             size_t bytes)
+{
+       struct rcar_fuse *fuse = priv;
+       int ret;
+
+       ret = pm_runtime_resume_and_get(fuse->dev);
+       if (ret < 0)
+               return ret;
+
+       __ioread32_copy(val, fuse->base + offset, bytes / 4);
+
+       pm_runtime_put(fuse->dev);
+
+       return 0;
+}
+
+static int rcar_fuse_probe(struct platform_device *pdev)
+{
+       struct device *dev = &pdev->dev;
+       const struct rcar_fuse_data *data = device_get_match_data(dev);
+       struct nvmem_config config = {
+               .dev = dev,
+               .name = "rcar-fuse",
+               .id = NVMEM_DEVID_NONE,
+               .owner = THIS_MODULE,
+               .type = NVMEM_TYPE_OTP,
+               .read_only = true,
+               .root_only = true,
+               .reg_read = rcar_fuse_reg_read,
+               .word_size = 4,
+               .stride = 4,
+       };
+       struct rcar_fuse *fuse;
+       struct resource *res;
+       int ret;
+
+       ret = devm_pm_runtime_enable(dev);
+       if (ret < 0)
+               return ret;
+
+       fuse = devm_kzalloc(dev, sizeof(*fuse), GFP_KERNEL);
+       if (!fuse)
+               return -ENOMEM;
+
+       fuse->base = devm_platform_get_and_ioremap_resource(pdev, data->bank,
+                                                           &res);
+       if (IS_ERR(fuse->base))
+               return PTR_ERR(fuse->base);
+
+       fuse->dev = dev;
+       fuse->keepouts[0].start = 0;
+       fuse->keepouts[0].end = data->start;
+       fuse->keepouts[1].start = data->end;
+       fuse->keepouts[1].end = resource_size(res);
+
+       config.keepout = fuse->keepouts;
+       config.nkeepout = ARRAY_SIZE(fuse->keepouts);
+       config.size = resource_size(res);
+       config.priv = fuse;
+
+       fuse->nvmem = devm_nvmem_register(dev, &config);
+       if (IS_ERR(fuse->nvmem))
+               return dev_err_probe(dev, PTR_ERR(fuse->nvmem),
+                                    "Failed to register NVMEM device\n");
+
+       return 0;
+}
+
+static const struct rcar_fuse_data rcar_fuse_v3u = {
+       .bank = 0,
+       .start = 0x0c0,
+       .end = 0x0e8,
+};
+
+static const struct rcar_fuse_data rcar_fuse_s4 = {
+       .bank = 0,
+       .start = 0x0c0,
+       .end = 0x14c,
+};
+
+static const struct rcar_fuse_data rcar_fuse_v4h = {
+       .bank = 1,
+       .start = 0x100,
+       .end = 0x1a0,
+};
+
+static const struct rcar_fuse_data rcar_fuse_v4m = {
+       .bank = 1,
+       .start = 0x100,
+       .end = 0x110,
+};
+
+static const struct of_device_id rcar_fuse_match[] = {
+       { .compatible = "renesas,r8a779a0-efuse", .data = &rcar_fuse_v3u },
+       { .compatible = "renesas,r8a779f0-efuse", .data = &rcar_fuse_s4 },
+       { .compatible = "renesas,r8a779g0-otp", .data = &rcar_fuse_v4h },
+       { .compatible = "renesas,r8a779h0-otp", .data = &rcar_fuse_v4m },
+       { /* sentinel */ }
+};
+
+static struct platform_driver rcar_fuse_driver = {
+       .probe = rcar_fuse_probe,
+       .driver = {
+               .name = "rcar_fuse",
+               .of_match_table = rcar_fuse_match,
+       },
+};
+module_platform_driver(rcar_fuse_driver);
+
+MODULE_DESCRIPTION("Renesas R-Car E-FUSE/OTP driver");
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Geert Uytterhoeven");