This driver utilizes the Power State Change Reasons Recording (PSCRR)
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/pscrr-nvmem.c | 121 ++++++++++++++++++++++++++++++
3 files changed, 133 insertions(+)
create mode 100644 drivers/power/reset/pscrr-nvmem.c
diff --git a/drivers/power/reset/Kconfig b/drivers/power/reset/Kconfig
index c6ce7e647048..8e50e495ef98 100644
--- a/drivers/power/reset/Kconfig
+++ b/drivers/power/reset/Kconfig
@@ -324,3 +324,14 @@ menuconfig PSCRR
timeouts.
If unsure, say N.
+
+if PSCRR
+
+config PSCRR_NVMEM
+ tristate "Generic NVMEM-based Power State Change Reason Recorder"
+ depends on OF
+ help
+ Enabling this option adds support for recording power state change
+ reasons in a NVMEM cell.
+
+endif
diff --git a/drivers/power/reset/Makefile b/drivers/power/reset/Makefile
index e618c34a30f9..3860dbbacb23 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_PSCRR) += pscrr.o
+obj-$(CONFIG_PSCRR_NVMEM) += pscrr-nvmem.o
obj-$(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/pscrr-nvmem.c b/drivers/power/reset/pscrr-nvmem.c
new file mode 100644
index 000000000000..fe9053b78b79
--- /dev/null
+++ b/drivers/power/reset/pscrr-nvmem.c
@@ -0,0 +1,121 @@
+// 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/pscrr.h>
+
+struct pscrr_nvmem {
+ struct pscrr_device pscrr_dev;
+ struct nvmem_cell *cell;
+ size_t max_magic_bytes;
+};
+
+static int pscrr_nvmem_write(struct pscrr_device *pscrr_dev, u32 magic)
+{
+ struct pscrr_nvmem *priv = container_of(pscrr_dev, struct pscrr_nvmem,
+ pscrr_dev);
+ 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(pscrr_dev->dev, "update reason bits failed: %pe\n",
+ ERR_PTR(ret));
+ return ret;
+ }
+
+ return 0;
+}
+
+static int pscrr_nvmem_read(struct pscrr_device *pscrr_dev, u32 *magic)
+{
+ struct pscrr_nvmem *priv = container_of(pscrr_dev, struct pscrr_nvmem,
+ pscrr_dev);
+ size_t len;
+ void *buf;
+
+ buf = nvmem_cell_read(priv->cell, &len);
+ if (IS_ERR(buf))
+ return PTR_ERR(buf);
+
+ *magic = 0;
+ memcpy(magic, buf, min(len, sizeof(*magic)));
+ kfree(buf);
+
+ return 0;
+}
+
+static int pscrr_nvmem_probe(struct platform_device *pdev)
+{
+ size_t bytes, bits, magic_bits;
+ struct pscrr_nvmem *priv;
+ const char *pscr = "pscr";
+ int ret;
+
+ priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
+ if (!priv)
+ return -ENOMEM;
+
+ priv->pscrr_dev.dev = &pdev->dev;
+ priv->pscrr_dev.write = pscrr_nvmem_write;
+ priv->pscrr_dev.read = pscrr_nvmem_read;
+
+ 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_pscrr_register(&pdev->dev, &priv->pscrr_dev);
+ if (ret)
+ return dev_err_probe(&pdev->dev, ret, "failed to register pscr driver\n");
+
+ magic_bits = fls(priv->pscrr_dev.max_magic_val);
+ 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 handle_last_pscr(&priv->pscrr_dev);
+}
+
+static const struct of_device_id pscrr_nvmem_of_match[] = {
+ { .compatible = "pscrr-nvmem" },
+ {}
+};
+MODULE_DEVICE_TABLE(of, pscrr_nvmem_of_match);
+
+static struct platform_driver pscrr_nvmem_driver = {
+ .probe = pscrr_nvmem_probe,
+ .driver = {
+ .name = "pscrr-nvmem",
+ .of_match_table = pscrr_nvmem_of_match,
+ },
+};
+module_platform_driver(pscrr_nvmem_driver);
+
+MODULE_AUTHOR("Oleksij Rempel <o.rempel@xxxxxxxxxxxxxx>");
+MODULE_DESCRIPTION("NVMEM Driver for Power State Change Reason Recording");
+MODULE_LICENSE("GPL");
--
2.39.2
