drivers: move the early platform device support to arch/sh

SuperH is the only user of the current implementation of early platform
device support. We want to introduce a more robust approach to early
probing. As the first step - move all the current early platform code
to arch/sh.

In order not to export internal drivers/base functions to arch code for
this temporary solution - copy the two needed routines for driver
matching from drivers/base/platform.c to arch/sh/drivers/platform_early.c.

Also: call early_platform_cleanup() from subsys_initcall() so that it's
called after all early devices are probed.

Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>
Cc: Rich Felker <dalias@libc.org>
Link: https://lore.kernel.org/r/20191003092913.10731-2-brgl@bgdev.pl
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 61 insertions, 0 deletions

diff --git a/arch/sh/include/asm/platform_early.h b/arch/sh/include/asm/platform_early.h
new file mode 100644
index 000000000000..4590ab757d5f
--- /dev/null
+++ b/arch/sh/include/asm/platform_early.h
@@ -0,0 +1,61 @@
+/* SPDX--License-Identifier: GPL-2.0 */
+
+#ifndef __PLATFORM_EARLY__
+#define __PLATFORM_EARLY__
+
+#include <linux/types.h>
+#include <linux/platform_device.h>
+#include <linux/pm_runtime.h>
+#include <linux/slab.h>
+
+struct early_platform_driver {
+	const char *class_str;
+	struct platform_driver *pdrv;
+	struct list_head list;
+	int requested_id;
+	char *buffer;
+	int bufsize;
+};
+
+#define EARLY_PLATFORM_ID_UNSET -2
+#define EARLY_PLATFORM_ID_ERROR -3
+
+extern int early_platform_driver_register(struct early_platform_driver *epdrv,
+					  char *buf);
+extern void early_platform_add_devices(struct platform_device **devs, int num);
+
+static inline int is_early_platform_device(struct platform_device *pdev)
+{
+	return !pdev->dev.driver;
+}
+
+extern void early_platform_driver_register_all(char *class_str);
+extern int early_platform_driver_probe(char *class_str,
+				       int nr_probe, int user_only);
+
+#define early_platform_init(class_string, platdrv)		\
+	early_platform_init_buffer(class_string, platdrv, NULL, 0)
+
+#ifndef MODULE
+#define early_platform_init_buffer(class_string, platdrv, buf, bufsiz)	\
+static __initdata struct early_platform_driver early_driver = {		\
+	.class_str = class_string,					\
+	.buffer = buf,							\
+	.bufsize = bufsiz,						\
+	.pdrv = platdrv,						\
+	.requested_id = EARLY_PLATFORM_ID_UNSET,			\
+};									\
+static int __init early_platform_driver_setup_func(char *buffer)	\
+{									\
+	return early_platform_driver_register(&early_driver, buffer);	\
+}									\
+early_param(class_string, early_platform_driver_setup_func)
+#else /* MODULE */
+#define early_platform_init_buffer(class_string, platdrv, buf, bufsiz)	\
+static inline char *early_platform_driver_setup_func(void)		\
+{									\
+	return bufsiz ? buf : NULL;					\
+}
+#endif /* MODULE */
+
+#endif /* __PLATFORM_EARLY__ */