[PATCH v2 1/2] Port SoC framework from Linux

[Marco Felsch]

This adds the initial support for the Linux soc framework which can be
used to register all SoC relevant informations. The framework can be
used by driver to check for errata for an specific soc(-revision) in the
future since this require porting the matching function.

For now it gathers all required SoC information and provide a standard
interface to query the data via device params.

Signed-off-by: Marco Felsch <m.felsch at pengutronix.de>
---
Changelog:
v2:
 - nothing

 drivers/base/Kconfig    |   3 +
 drivers/base/Makefile   |   1 +
 drivers/base/soc.c      | 123 ++++++++++++++++++++++++++++++++++++++++
 include/linux/sys_soc.h |  39 +++++++++++++
 4 files changed, 166 insertions(+)
 create mode 100644 drivers/base/soc.c
 create mode 100644 include/linux/sys_soc.h

diff --git a/drivers/base/Kconfig b/drivers/base/Kconfig
index 612a84be33e7..21a4793cfa47 100644
--- a/drivers/base/Kconfig
+++ b/drivers/base/Kconfig
@@ -6,4 +6,7 @@ config PM_GENERIC_DOMAINS
 config FEATURE_CONTROLLER
 	bool "Feature controller support" if COMPILE_TEST || SANDBOX
 
+config SOC_BUS
+	bool
+
 source "drivers/base/regmap/Kconfig"
diff --git a/drivers/base/Makefile b/drivers/base/Makefile
index e8e354cdaabc..acc53763da35 100644
--- a/drivers/base/Makefile
+++ b/drivers/base/Makefile
@@ -7,3 +7,4 @@ obj-y	+= regmap/
 
 obj-$(CONFIG_PM_GENERIC_DOMAINS) += power.o
 obj-$(CONFIG_FEATURE_CONTROLLER) += featctrl.o
+obj-$(CONFIG_SOC_BUS) += soc.o
diff --git a/drivers/base/soc.c b/drivers/base/soc.c
new file mode 100644
index 000000000000..a481f8987b56
--- /dev/null
+++ b/drivers/base/soc.c
@@ -0,0 +1,123 @@
+// SPDX-License-Identifier: GPL-2.0-only
+// SPDX-FileCopyrightText: 2024 Marco Felsch, Pengutronix
+/*
+ * Based on Linux drivers/base/soc.c:
+ * Copyright (C) ST-Ericsson SA 2011
+ */
+
+#include <common.h>
+#include <init.h>
+#include <of.h>
+
+#include <linux/slab.h>
+#include <linux/sys_soc.h>
+#include <linux/err.h>
+
+struct soc_device {
+	struct device dev;
+	struct soc_device_attribute *attr;
+};
+
+static struct bus_type soc_bus_type = {
+	.name  = "soc",
+};
+static bool soc_bus_registered;
+
+static void soc_device_add_params(struct soc_device *soc_dev)
+{
+	struct soc_device_attribute *attr = soc_dev->attr;
+	struct device *dev = &soc_dev->dev;
+
+	if (attr->machine)
+		dev_add_param_string_fixed(dev, "machine", attr->machine);
+	if (attr->family)
+		dev_add_param_string_fixed(dev, "family", attr->family);
+	if (attr->revision)
+		dev_add_param_string_fixed(dev, "revision", attr->revision);
+	if (attr->serial_number)
+		dev_add_param_string_fixed(dev, "serial_number", attr->serial_number);
+	if (attr->soc_id)
+		dev_add_param_string_fixed(dev, "soc_id", attr->soc_id);
+}
+
+static void soc_device_get_machine(struct soc_device_attribute *soc_dev_attr)
+{
+	struct device_node *np;
+
+	if (soc_dev_attr->machine)
+		return;
+
+	np = of_find_node_by_path("/");
+	of_property_read_string(np, "model", &soc_dev_attr->machine);
+	of_node_put(np);
+}
+
+static struct soc_device_attribute *early_soc_dev_attr;
+
+struct soc_device *soc_device_register(struct soc_device_attribute *soc_dev_attr)
+{
+	struct soc_device *soc_dev;
+	int ret;
+
+	soc_device_get_machine(soc_dev_attr);
+
+	if (!soc_bus_registered) {
+		if (early_soc_dev_attr)
+			return ERR_PTR(-EBUSY);
+		early_soc_dev_attr = soc_dev_attr;
+		return NULL;
+	}
+
+	soc_dev = kzalloc(sizeof(*soc_dev), GFP_KERNEL);
+	if (!soc_dev) {
+		ret = -ENOMEM;
+		goto out1;
+	}
+
+	soc_dev->attr = soc_dev_attr;
+	soc_dev->dev.bus = &soc_bus_type;
+	soc_dev->dev.id = DEVICE_ID_DYNAMIC;
+
+	dev_set_name(&soc_dev->dev, "soc");
+
+	ret = device_register(&soc_dev->dev);
+	if (ret) {
+		put_device(&soc_dev->dev);
+		goto out2;
+	}
+
+	soc_device_add_params(soc_dev);
+
+	return soc_dev;
+
+out2:
+	kfree(soc_dev);
+out1:
+	return ERR_PTR(ret);
+}
+EXPORT_SYMBOL_GPL(soc_device_register);
+
+/* Ensure soc_dev->attr is freed after calling soc_device_unregister. */
+void soc_device_unregister(struct soc_device *soc_dev)
+{
+	device_unregister(&soc_dev->dev);
+	kfree(soc_dev);
+	early_soc_dev_attr = NULL;
+}
+EXPORT_SYMBOL_GPL(soc_device_unregister);
+
+static int __init soc_bus_register(void)
+{
+	int ret;
+
+	ret = bus_register(&soc_bus_type);
+	if (ret)
+		return ret;
+	soc_bus_registered = true;
+
+	if (early_soc_dev_attr)
+		return PTR_ERR(soc_device_register(early_soc_dev_attr));
+
+	return 0;
+}
+core_initcall(soc_bus_register);
diff --git a/include/linux/sys_soc.h b/include/linux/sys_soc.h
new file mode 100644
index 000000000000..fd597ae54096
--- /dev/null
+++ b/include/linux/sys_soc.h
@@ -0,0 +1,39 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * Copyright (C) ST-Ericsson SA 2011
+ * Author: Lee Jones <lee.jones at linaro.org> for ST-Ericsson.
+ */
+#ifndef __SOC_BUS_H
+#define __SOC_BUS_H
+
+#include <linux/device.h>
+
+struct soc_device_attribute {
+	const char *machine;
+	const char *family;
+	const char *revision;
+	const char *serial_number;
+	const char *soc_id;
+	const void *data;
+};
+
+/**
+ * soc_device_register - register SoC as a device
+ * @soc_plat_dev_attr: Attributes passed from platform to be attributed to a SoC
+ */
+struct soc_device *soc_device_register(
+	struct soc_device_attribute *soc_plat_dev_attr);
+
+/**
+ * soc_device_unregister - unregister SoC device
+ * @dev: SoC device to be unregistered
+ */
+void soc_device_unregister(struct soc_device *soc_dev);
+
+/**
+ * soc_device_to_device - helper function to fetch struct device
+ * @soc: Previously registered SoC device container
+ */
+struct device *soc_device_to_device(struct soc_device *soc);
+
+#endif /* __SOC_BUS_H */
-- 
2.39.2