On 10/04/2022 14:54, Sven Peter wrote:
Apple SoCs contain eFuses used to store factory-programmed data such as calibration values for the PCIe or the Type-C PHY. They are organized as 32bit values exposed as MMIO. Signed-off-by: Sven Peter <sven@xxxxxxxxxxxxx>
Applied all 3, thanks, --srini
--- v3 -> v4: - rebased on 5.18-rc1 and split off MAINTAINER changes as requested by Srinivas Kandagatla v2 -> v3: - removed .owner = THIS_MODULE again since it's already done by the core as pointed out by Krzysztof Kozlowski v1 -> v2: - fixed sparse warning about __iomem by introducing struct apple_efuses_priv as done in other nvmem drivers - make sure the driver actually works as a module by setting .owner to THIS_MODULE and adding MODULE_DEVICE_TABLE pointed out by Joey Gouly drivers/nvmem/Kconfig | 12 ++++++ drivers/nvmem/Makefile | 2 + drivers/nvmem/apple-efuses.c | 80 ++++++++++++++++++++++++++++++++++++ 3 files changed, 94 insertions(+) create mode 100644 drivers/nvmem/apple-efuses.c diff --git a/drivers/nvmem/Kconfig b/drivers/nvmem/Kconfig index 555aa77a574d..6283e09cc1e9 100644 --- a/drivers/nvmem/Kconfig +++ b/drivers/nvmem/Kconfig @@ -324,4 +324,16 @@ config NVMEM_SUNPLUS_OCOTP This driver can also be built as a module. If so, the module will be called nvmem-sunplus-ocotp.+config NVMEM_APPLE_EFUSES+ tristate "Apple eFuse support" + depends on ARCH_APPLE || COMPILE_TEST + default ARCH_APPLE + help + Say y here to enable support for reading eFuses on Apple SoCs + such as the M1. These are e.g. used to store factory programmed + calibration data required for the PCIe or the USB-C PHY. + + This driver can also be built as a module. If so, the module will + be called nvmem-apple-efuses. + endif diff --git a/drivers/nvmem/Makefile b/drivers/nvmem/Makefile index 891958e29d25..00e136a0a123 100644 --- a/drivers/nvmem/Makefile +++ b/drivers/nvmem/Makefile @@ -65,3 +65,5 @@ obj-$(CONFIG_NVMEM_LAYERSCAPE_SFP) += nvmem-layerscape-sfp.o nvmem-layerscape-sfp-y := layerscape-sfp.o obj-$(CONFIG_NVMEM_SUNPLUS_OCOTP) += nvmem_sunplus_ocotp.o nvmem_sunplus_ocotp-y := sunplus-ocotp.o +obj-$(CONFIG_NVMEM_APPLE_EFUSES) += nvmem-apple-efuses.o +nvmem-apple-efuses-y := apple-efuses.o diff --git a/drivers/nvmem/apple-efuses.c b/drivers/nvmem/apple-efuses.c new file mode 100644 index 000000000000..9b7c87102104 --- /dev/null +++ b/drivers/nvmem/apple-efuses.c @@ -0,0 +1,80 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Apple SoC eFuse driver + * + * Copyright (C) The Asahi Linux Contributors + */ + +#include <linux/io.h> +#include <linux/mod_devicetable.h> +#include <linux/module.h> +#include <linux/nvmem-provider.h> +#include <linux/platform_device.h> + +struct apple_efuses_priv { + void __iomem *fuses; +}; + +static int apple_efuses_read(void *context, unsigned int offset, void *val, + size_t bytes) +{ + struct apple_efuses_priv *priv = context; + u32 *dst = val; + + while (bytes >= sizeof(u32)) { + *dst++ = readl_relaxed(priv->fuses + offset); + bytes -= sizeof(u32); + offset += sizeof(u32); + } + + return 0; +} + +static int apple_efuses_probe(struct platform_device *pdev) +{ + struct apple_efuses_priv *priv; + struct resource *res; + struct nvmem_config config = { + .dev = &pdev->dev, + .read_only = true, + .reg_read = apple_efuses_read, + .stride = sizeof(u32), + .word_size = sizeof(u32), + .name = "apple_efuses_nvmem", + .id = NVMEM_DEVID_AUTO, + .root_only = true, + }; + + priv = devm_kzalloc(config.dev, sizeof(*priv), GFP_KERNEL); + if (!priv) + return -ENOMEM; + + priv->fuses = devm_platform_get_and_ioremap_resource(pdev, 0, &res); + if (IS_ERR(priv->fuses)) + return PTR_ERR(priv->fuses); + + config.priv = priv; + config.size = resource_size(res); + + return PTR_ERR_OR_ZERO(devm_nvmem_register(config.dev, &config)); +} + +static const struct of_device_id apple_efuses_of_match[] = { + { .compatible = "apple,efuses", }, + {} +}; + +MODULE_DEVICE_TABLE(of, apple_efuses_of_match); + +static struct platform_driver apple_efuses_driver = { + .driver = { + .name = "apple_efuses", + .of_match_table = apple_efuses_of_match, + }, + .probe = apple_efuses_probe, +}; + +module_platform_driver(apple_efuses_driver); + +MODULE_AUTHOR("Sven Peter <sven@xxxxxxxxxxxxx>"); +MODULE_LICENSE("GPL");
