Raspberry Pis have OTP registers which can be accessed through the videocore firmware. Add a nvmem driver to support these OTP registers.
Signed-off-by: Gregor Herburger <[email protected]> --- drivers/nvmem/Kconfig | 10 +++ drivers/nvmem/Makefile | 1 + drivers/nvmem/raspberrypi-otp.c | 119 +++++++++++++++++++++++++++++ include/soc/bcm2835/raspberrypi-firmware.h | 9 +++ 4 files changed, 139 insertions(+) diff --git a/drivers/nvmem/Kconfig b/drivers/nvmem/Kconfig index 74ddbd0f79b0..4ecfb0dfbe6b 100644 --- a/drivers/nvmem/Kconfig +++ b/drivers/nvmem/Kconfig @@ -483,4 +483,14 @@ config NVMEM_QORIQ_EFUSE This driver can also be built as a module. If so, the module will be called nvmem_qoriq_efuse. +config NVMEM_RASPBERRYPI_OTP + tristate "Raspberry Pi OTP support" + depends on RASPBERRYPI_FIRMWARE || COMPILE_TEST + help + This driver provides access to the Raspberry Pi OTP memory via the + nvmem subsystem. The driver supports the customer OTP as well as the + device specific private key OTP (BCM2712 only). + + This driver can also be built as a module. If so, the module + will be called raspberrypi-otp. endif diff --git a/drivers/nvmem/Makefile b/drivers/nvmem/Makefile index 7252b8ec88d4..8ca2095e068f 100644 --- a/drivers/nvmem/Makefile +++ b/drivers/nvmem/Makefile @@ -95,3 +95,4 @@ obj-$(CONFIG_NVMEM_ZYNQMP) += nvmem_zynqmp_nvmem.o nvmem_zynqmp_nvmem-y := zynqmp_nvmem.o obj-$(CONFIG_NVMEM_QORIQ_EFUSE) += nvmem-qoriq-efuse.o nvmem-qoriq-efuse-y := qoriq-efuse.o +obj-$(CONFIG_NVMEM_RASPBERRYPI_OTP) += raspberrypi-otp.o diff --git a/drivers/nvmem/raspberrypi-otp.c b/drivers/nvmem/raspberrypi-otp.c new file mode 100644 index 000000000000..83624aa85bb3 --- /dev/null +++ b/drivers/nvmem/raspberrypi-otp.c @@ -0,0 +1,119 @@ +// SPDX-License-Identifier: GPL-2.0-only + +#include <linux/overflow.h> +#include <linux/module.h> +#include <linux/nvmem-provider.h> +#include <linux/platform_device.h> +#include <soc/bcm2835/raspberrypi-firmware.h> + +struct rpi_otp_priv { + struct rpi_firmware *fw; + struct device *dev; + u32 read_tag; + u32 write_tag; +}; + +struct rpi_otp_header { + u32 start; + u32 count; + u32 data[] __counted_by(count); +}; + +static int rpi_otp_read(void *context, unsigned int offset, void *buf, size_t bytes) +{ + struct rpi_otp_priv *priv = context; + struct rpi_otp_header *fwbuf; + u32 count = bytes / 4; + int ret; + + fwbuf = kzalloc(struct_size(fwbuf, data, count), GFP_KERNEL); + if (!fwbuf) + return -ENOMEM; + + fwbuf->start = offset / 4; + fwbuf->count = count; + + ret = rpi_firmware_property(priv->fw, priv->read_tag, fwbuf, + sizeof(struct rpi_otp_header) + bytes); + if (ret) + goto out; + + memcpy(buf, fwbuf->data, bytes); + +out: + kfree(fwbuf); + return ret; +} + +static int rpi_otp_write(void *context, unsigned int offset, void *val, size_t bytes) +{ + struct rpi_otp_priv *priv = context; + struct rpi_otp_header *fwbuf; + u32 count = bytes / 4; + int ret; + + fwbuf = kzalloc(struct_size(fwbuf, data, count), GFP_KERNEL); + if (!fwbuf) + return -ENOMEM; + + fwbuf->start = offset / 4; + fwbuf->count = count; + memcpy(fwbuf->data, val, bytes); + + ret = rpi_firmware_property(priv->fw, priv->write_tag, fwbuf, + sizeof(struct rpi_otp_header) + bytes); + + kfree(fwbuf); + return ret; +} + +static int rpi_otp_probe(struct platform_device *pdev) +{ + struct device *dev = &pdev->dev; + struct nvmem_device *nvmem; + struct rpi_otp_priv *priv; + const struct rpi_otp_driver_data *data; + struct nvmem_config config = { + .read_only = false, + .word_size = 4, + .stride = 4, + .reg_read = rpi_otp_read, + .reg_write = rpi_otp_write, + .id = NVMEM_DEVID_NONE, + }; + + priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL); + if (!priv) + return -ENOMEM; + + data = dev_get_platdata(dev); + if (!data) + return -ENODEV; + + priv->fw = dev_get_drvdata(dev->parent); + priv->dev = dev; + priv->read_tag = data->read_tag; + priv->write_tag = data->write_tag; + config.dev = dev; + config.priv = priv; + config.name = data->name; + config.size = data->size; + + nvmem = devm_nvmem_register(dev, &config); + if (IS_ERR(nvmem)) + return dev_err_probe(dev, PTR_ERR(nvmem), "error registering nvmem config\n"); + + return 0; +} + +static struct platform_driver raspberry_otp_driver = { + .probe = rpi_otp_probe, + .driver = { + .name = "raspberrypi-otp", + }, +}; +module_platform_driver(raspberry_otp_driver); + +MODULE_AUTHOR("Gregor Herburger <[email protected]>"); +MODULE_DESCRIPTION("Raspberry Pi OTP driver"); +MODULE_LICENSE("GPL"); diff --git a/include/soc/bcm2835/raspberrypi-firmware.h b/include/soc/bcm2835/raspberrypi-firmware.h index e1f87fbfe554..ae73c9cd19ba 100644 --- a/include/soc/bcm2835/raspberrypi-firmware.h +++ b/include/soc/bcm2835/raspberrypi-firmware.h @@ -92,6 +92,8 @@ enum rpi_firmware_property_tag { RPI_FIRMWARE_SET_POE_HAT_VAL = 0x00030050, RPI_FIRMWARE_NOTIFY_XHCI_RESET = 0x00030058, RPI_FIRMWARE_NOTIFY_DISPLAY_DONE = 0x00030066, + RPI_FIRMWARE_GET_PRIVATE_OTP = 0x00030081, + RPI_FIRMWARE_SET_PRIVATE_OTP = 0x00038081, /* Dispmanx TAGS */ RPI_FIRMWARE_FRAMEBUFFER_ALLOCATE = 0x00040001, @@ -174,6 +176,13 @@ struct rpi_firmware_clk_rate_request { .id = cpu_to_le32(_id), \ } +struct rpi_otp_driver_data { + const char *name; + u32 read_tag; + u32 write_tag; + int size; +}; + #if IS_ENABLED(CONFIG_RASPBERRYPI_FIRMWARE) int rpi_firmware_property(struct rpi_firmware *fw, u32 tag, void *data, size_t len); -- 2.47.3
