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Date: Wed, 24 Jan 2024 13:22:02 +0100
From: Oleksij Rempel <o.rempel@...gutronix.de>
To: Sebastian Reichel <sre@...nel.org>,
Rob Herring <robh+dt@...nel.org>,
Krzysztof Kozlowski <krzysztof.kozlowski+dt@...aro.org>,
Conor Dooley <conor+dt@...nel.org>,
Srinivas Kandagatla <srinivas.kandagatla@...aro.org>
Cc: Oleksij Rempel <o.rempel@...gutronix.de>,
kernel@...gutronix.de,
linux-kernel@...r.kernel.org,
Liam Girdwood <lgirdwood@...il.com>,
Mark Brown <broonie@...nel.org>,
"Rafael J. Wysocki" <rafael@...nel.org>,
Daniel Lezcano <daniel.lezcano@...aro.org>,
Zhang Rui <rui.zhang@...el.com>,
Lukasz Luba <lukasz.luba@....com>,
linux-pm@...r.kernel.org,
devicetree@...r.kernel.org,
Søren Andersen <san@...v.dk>
Subject: [PATCH v2 6/8] power: reset: add PSCR NVMEM Driver for Recording Power State Change Reasons
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@...gutronix.de>
---
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@...gutronix.de>
+/*
+ * 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@...gutronix.de>");
+MODULE_DESCRIPTION("NVMEM Driver for Power State Change Reason Recording");
+MODULE_LICENSE("GPL");
--
2.39.2
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