On 06/03/2022 13:18, 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>
> ---
> 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 <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,
> + .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,
You wrote it also in changelog, but why do you need it? Doesn't core set
it? Coccinelle should complain about this as well.
Best regards,
Krzysztof
