This driver utilizes the Power State Change Reasons (PSCR) framework to store specific power state change information, such as shutdown or reboot reasons, into a designated non-volatile memory (NVMEM) cell. Signed-off-by: Oleksij Rempel <o.rempel@xxxxxxxxxxxxxx> --- drivers/power/reset/Kconfig | 11 ++++ drivers/power/reset/Makefile | 1 + drivers/power/reset/pscr-nvmem.c | 100 +++++++++++++++++++++++++++++++ 3 files changed, 112 insertions(+) create mode 100644 drivers/power/reset/pscr-nvmem.c diff --git a/drivers/power/reset/Kconfig b/drivers/power/reset/Kconfig index da76e84302b9..a110dff599af 100644 --- a/drivers/power/reset/Kconfig +++ b/drivers/power/reset/Kconfig @@ -324,3 +324,14 @@ menuconfig PSCR timeouts. If unsure, say N. + +if PSCR + +config PSCR_NVMEM + tristate "Generic NVMEM-based Power State Change Reason Tracking" + depends on OF + help + Enabling this option adds support for storing power state change + reasons in a NVMEM cell. + +endif diff --git a/drivers/power/reset/Makefile b/drivers/power/reset/Makefile index d9d744302c68..e7985d81ac8a 100644 --- a/drivers/power/reset/Makefile +++ b/drivers/power/reset/Makefile @@ -32,6 +32,7 @@ obj-$(CONFIG_POWER_RESET_SYSCON) += syscon-reboot.o obj-$(CONFIG_POWER_RESET_SYSCON_POWEROFF) += syscon-poweroff.o obj-$(CONFIG_POWER_RESET_RMOBILE) += rmobile-reset.o obj-$(CONFIG_PSCR) += pscr.o +obj-$(CONFIG_PSCR_NVMEM) += pscr-nvmem.o obj-$(CONFIG_REBOOT_MODE) += reboot-mode.o obj-$(CONFIG_SYSCON_REBOOT_MODE) += syscon-reboot-mode.o obj-$(CONFIG_POWER_RESET_SC27XX) += sc27xx-poweroff.o diff --git a/drivers/power/reset/pscr-nvmem.c b/drivers/power/reset/pscr-nvmem.c new file mode 100644 index 000000000000..74048341b7d7 --- /dev/null +++ b/drivers/power/reset/pscr-nvmem.c @@ -0,0 +1,100 @@ +// SPDX-License-Identifier: GPL-2.0 +// Copyright (c) Vaisala Oyj. All rights reserved. +// Copyright (c) 2024 Pengutronix, Oleksij Rempel <kernel@xxxxxxxxxxxxxx> +/* + * Based on drivers/power/reset/nvmem-reboot-mode.c + * Copyright (c) Vaisala Oyj. All rights reserved. + */ + +#include <linux/init.h> +#include <linux/kernel.h> +#include <linux/module.h> +#include <linux/nvmem-consumer.h> +#include <linux/of.h> +#include <linux/platform_device.h> +#include <linux/pscr.h> + +struct pscr_nvmem { + struct pscr_driver pscr_drv; + struct nvmem_cell *cell; + size_t max_magic_bytes; +}; + +static int pscr_nvmem_write(struct pscr_driver *pscr_drv, u32 magic) +{ + struct pscr_nvmem *priv = container_of(pscr_drv, struct pscr_nvmem, + pscr_drv); + size_t size = min(priv->max_magic_bytes, sizeof(magic)); + int ret; + + ret = nvmem_cell_write(priv->cell, &magic, size); + if (ret < 0) + dev_err(pscr_drv->dev, "update reason bits failed: %pe\n", + ERR_PTR(ret)); + + return ret; +} + +static int pscr_nvmem_probe(struct platform_device *pdev) +{ + const char *pscr = "pscr"; + struct pscr_nvmem *priv; + size_t bytes, bits, magic_bits; + int ret; + + priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL); + if (!priv) + return -ENOMEM; + + priv->pscr_drv.dev = &pdev->dev; + priv->pscr_drv.write = pscr_nvmem_write; + + priv->cell = devm_nvmem_cell_get(&pdev->dev, pscr); + if (IS_ERR(priv->cell)) + return dev_err_probe(&pdev->dev, PTR_ERR(priv->cell), + "failed to get the nvmem %s cell\n", pscr); + + ret = nvmem_cell_get_size(priv->cell, &bytes, &bits); + if (ret < 0) + return dev_err_probe(&pdev->dev, ret, "failed to get the nvmem %s size\n", + pscr); + + if (!bytes || bytes > sizeof(u32) || bits > 32) + return dev_err_probe(&pdev->dev, -EINVAL, "invalid nvmem %s size. bytes: %zu, bits: %zu\n", + pscr, bytes, bits); + + ret = devm_pscr_register(&pdev->dev, &priv->pscr_drv); + if (ret) + return dev_err_probe(&pdev->dev, ret, "failed to register pscr driver\n"); + + magic_bits = fls(priv->pscr_drv.max_magic); + priv->max_magic_bytes = DIV_ROUND_UP(magic_bits, 8); + + if (!bits) + bits = bytes * 8; + + if (magic_bits > bits) + return dev_err_probe(&pdev->dev, -EINVAL, "provided magic can't fit into nvmem %s. bytes: %zu, bits: %zu, magic_bits: %zu\n", + pscr, bytes, bits, magic_bits); + + return ret; +} + +static const struct of_device_id pscr_nvmem_of_match[] = { + { .compatible = "pscr-nvmem" }, + {} +}; +MODULE_DEVICE_TABLE(of, pscr_nvmem_of_match); + +static struct platform_driver pscr_nvmem_driver = { + .probe = pscr_nvmem_probe, + .driver = { + .name = "pscr-nvmem", + .of_match_table = pscr_nvmem_of_match, + }, +}; +module_platform_driver(pscr_nvmem_driver); + +MODULE_AUTHOR("Oleksij Rempel <o.rempel@xxxxxxxxxxxxxx>"); +MODULE_DESCRIPTION("NVMEM Driver for Power State Change Reason Tracking"); +MODULE_LICENSE("GPL v2"); -- 2.39.2