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Sun, 6 Mar 2022 07:18:35 -0500 (EST) From: Sven Peter To: Srinivas Kandagatla Cc: Sven Peter , Rob Herring , Krzysztof Kozlowsk , Joey Gouly , Hector Martin , Alyssa Rosenzweig , Mark Kettenis , linux-arm-kernel@lists.infradead.org, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH v2 2/2] nvmem: Add Apple eFuse driver Date: Sun, 6 Mar 2022 13:18:16 +0100 Message-Id: <20220306121816.70537-2-sven@svenpeter.dev> X-Mailer: git-send-email 2.30.1 (Apple Git-130) In-Reply-To: <20220306121816.70537-1-sven@svenpeter.dev> References: <20220306121816.70537-1-sven@svenpeter.dev> MIME-Version: 1.0 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20220306_041841_615905_E2A513B8 X-CRM114-Status: GOOD ( 21.11 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org 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 --- 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 MAINTAINERS | 1 + drivers/nvmem/Kconfig | 12 ++++++ drivers/nvmem/Makefile | 2 + drivers/nvmem/apple-efuses.c | 82 ++++++++++++++++++++++++++++++++++++ 4 files changed, 97 insertions(+) create mode 100644 drivers/nvmem/apple-efuses.c diff --git a/MAINTAINERS b/MAINTAINERS index f70d8525cbd4..e3e973a3f651 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -1781,6 +1781,7 @@ F: drivers/i2c/busses/i2c-pasemi-core.c F: drivers/i2c/busses/i2c-pasemi-platform.c F: drivers/irqchip/irq-apple-aic.c F: drivers/mailbox/apple-mailbox.c +F: drivers/nvmem/apple-efuses.c F: drivers/pinctrl/pinctrl-apple-gpio.c F: drivers/soc/apple/* F: drivers/watchdog/apple_wdt.c diff --git a/drivers/nvmem/Kconfig b/drivers/nvmem/Kconfig index da414617a54d..bba29d1aec96 100644 --- a/drivers/nvmem/Kconfig +++ b/drivers/nvmem/Kconfig @@ -300,4 +300,16 @@ config NVMEM_BRCM_NVRAM This driver provides support for Broadcom's NVRAM that can be accessed using I/O mapping. +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 dcbbde35b6a8..1a8e54691d3e 100644 --- a/drivers/nvmem/Makefile +++ b/drivers/nvmem/Makefile @@ -61,3 +61,5 @@ obj-$(CONFIG_NVMEM_RMEM) += nvmem-rmem.o nvmem-rmem-y := rmem.o obj-$(CONFIG_NVMEM_BRCM_NVRAM) += nvmem_brcm_nvram.o nvmem_brcm_nvram-y := brcm_nvram.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..dd5576ec5408 --- /dev/null +++ b/drivers/nvmem/apple-efuses.c @@ -0,0 +1,82 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Apple SoC eFuse driver + * + * Copyright (C) The Asahi Linux Contributors + */ + +#include +#include +#include +#include +#include + +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, + .owner = THIS_MODULE, + .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, + .owner = THIS_MODULE, + }, + .probe = apple_efuses_probe, +}; + +module_platform_driver(apple_efuses_driver); + +MODULE_AUTHOR("Sven Peter "); +MODULE_LICENSE("GPL");