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>

2 files changed, 348 insertions, 1 deletions

diff --git a/arch/sh/drivers/Makefile b/arch/sh/drivers/Makefile
index 3e93b434e604..56b0acace6e7 100644
--- a/arch/sh/drivers/Makefile
+++ b/arch/sh/drivers/Makefile
@@ -3,7 +3,7 @@
 # Makefile for the Linux SuperH-specific device drivers.
 #
 
-obj-y		+= dma/
+obj-y		+= dma/ platform_early.o
 
 obj-$(CONFIG_PCI)		+= pci/
 obj-$(CONFIG_SUPERHYWAY)	+= superhyway/
diff --git a/arch/sh/drivers/platform_early.c b/arch/sh/drivers/platform_early.c
new file mode 100644
index 000000000000..3dfe9f3541bb
--- /dev/null
+++ b/arch/sh/drivers/platform_early.c
@@ -0,0 +1,347 @@
+// SPDX--License-Identifier: GPL-2.0
+
+#include <asm/platform_early.h>
+#include <linux/mod_devicetable.h>
+#include <linux/pm.h>
+
+static __initdata LIST_HEAD(early_platform_driver_list);
+static __initdata LIST_HEAD(early_platform_device_list);
+
+static const struct platform_device_id *
+platform_match_id(const struct platform_device_id *id,
+		  struct platform_device *pdev)
+{
+	while (id->name[0]) {
+		if (strcmp(pdev->name, id->name) == 0) {
+			pdev->id_entry = id;
+			return id;
+		}
+		id++;
+	}
+	return NULL;
+}
+
+static int platform_match(struct device *dev, struct device_driver *drv)
+{
+	struct platform_device *pdev = to_platform_device(dev);
+	struct platform_driver *pdrv = to_platform_driver(drv);
+
+	/* When driver_override is set, only bind to the matching driver */
+	if (pdev->driver_override)
+		return !strcmp(pdev->driver_override, drv->name);
+
+	/* Then try to match against the id table */
+	if (pdrv->id_table)
+		return platform_match_id(pdrv->id_table, pdev) != NULL;
+
+	/* fall-back to driver name match */
+	return (strcmp(pdev->name, drv->name) == 0);
+}
+
+#ifdef CONFIG_PM
+static void device_pm_init_common(struct device *dev)
+{
+	if (!dev->power.early_init) {
+		spin_lock_init(&dev->power.lock);
+		dev->power.qos = NULL;
+		dev->power.early_init = true;
+	}
+}
+
+static void pm_runtime_early_init(struct device *dev)
+{
+	dev->power.disable_depth = 1;
+	device_pm_init_common(dev);
+}
+#else
+static void pm_runtime_early_init(struct device *dev) {}
+#endif
+
+/**
+ * early_platform_driver_register - register early platform driver
+ * @epdrv: early_platform driver structure
+ * @buf: string passed from early_param()
+ *
+ * Helper function for early_platform_init() / early_platform_init_buffer()
+ */
+int __init early_platform_driver_register(struct early_platform_driver *epdrv,
+					  char *buf)
+{
+	char *tmp;
+	int n;
+
+	/* Simply add the driver to the end of the global list.
+	 * Drivers will by default be put on the list in compiled-in order.
+	 */
+	if (!epdrv->list.next) {
+		INIT_LIST_HEAD(&epdrv->list);
+		list_add_tail(&epdrv->list, &early_platform_driver_list);
+	}
+
+	/* If the user has specified device then make sure the driver
+	 * gets prioritized. The driver of the last device specified on
+	 * command line will be put first on the list.
+	 */
+	n = strlen(epdrv->pdrv->driver.name);
+	if (buf && !strncmp(buf, epdrv->pdrv->driver.name, n)) {
+		list_move(&epdrv->list, &early_platform_driver_list);
+
+		/* Allow passing parameters after device name */
+		if (buf[n] == '\0' || buf[n] == ',')
+			epdrv->requested_id = -1;
+		else {
+			epdrv->requested_id = simple_strtoul(&buf[n + 1],
+							     &tmp, 10);
+
+			if (buf[n] != '.' || (tmp == &buf[n + 1])) {
+				epdrv->requested_id = EARLY_PLATFORM_ID_ERROR;
+				n = 0;
+			} else
+				n += strcspn(&buf[n + 1], ",") + 1;
+		}
+
+		if (buf[n] == ',')
+			n++;
+
+		if (epdrv->bufsize) {
+			memcpy(epdrv->buffer, &buf[n],
+			       min_t(int, epdrv->bufsize, strlen(&buf[n]) + 1));
+			epdrv->buffer[epdrv->bufsize - 1] = '\0';
+		}
+	}
+
+	return 0;
+}
+
+/**
+ * early_platform_add_devices - adds a number of early platform devices
+ * @devs: array of early platform devices to add
+ * @num: number of early platform devices in array
+ *
+ * Used by early architecture code to register early platform devices and
+ * their platform data.
+ */
+void __init early_platform_add_devices(struct platform_device **devs, int num)
+{
+	struct device *dev;
+	int i;
+
+	/* simply add the devices to list */
+	for (i = 0; i < num; i++) {
+		dev = &devs[i]->dev;
+
+		if (!dev->devres_head.next) {
+			pm_runtime_early_init(dev);
+			INIT_LIST_HEAD(&dev->devres_head);
+			list_add_tail(&dev->devres_head,
+				      &early_platform_device_list);
+		}
+	}
+}
+
+/**
+ * early_platform_driver_register_all - register early platform drivers
+ * @class_str: string to identify early platform driver class
+ *
+ * Used by architecture code to register all early platform drivers
+ * for a certain class. If omitted then only early platform drivers
+ * with matching kernel command line class parameters will be registered.
+ */
+void __init early_platform_driver_register_all(char *class_str)
+{
+	/* The "class_str" parameter may or may not be present on the kernel
+	 * command line. If it is present then there may be more than one
+	 * matching parameter.
+	 *
+	 * Since we register our early platform drivers using early_param()
+	 * we need to make sure that they also get registered in the case
+	 * when the parameter is missing from the kernel command line.
+	 *
+	 * We use parse_early_options() to make sure the early_param() gets
+	 * called at least once. The early_param() may be called more than
+	 * once since the name of the preferred device may be specified on
+	 * the kernel command line. early_platform_driver_register() handles
+	 * this case for us.
+	 */
+	parse_early_options(class_str);
+}
+
+/**
+ * early_platform_match - find early platform device matching driver
+ * @epdrv: early platform driver structure
+ * @id: id to match against
+ */
+static struct platform_device * __init
+early_platform_match(struct early_platform_driver *epdrv, int id)
+{
+	struct platform_device *pd;
+
+	list_for_each_entry(pd, &early_platform_device_list, dev.devres_head)
+		if (platform_match(&pd->dev, &epdrv->pdrv->driver))
+			if (pd->id == id)
+				return pd;
+
+	return NULL;
+}
+
+/**
+ * early_platform_left - check if early platform driver has matching devices
+ * @epdrv: early platform driver structure
+ * @id: return true if id or above exists
+ */
+static int __init early_platform_left(struct early_platform_driver *epdrv,
+				       int id)
+{
+	struct platform_device *pd;
+
+	list_for_each_entry(pd, &early_platform_device_list, dev.devres_head)
+		if (platform_match(&pd->dev, &epdrv->pdrv->driver))
+			if (pd->id >= id)
+				return 1;
+
+	return 0;
+}
+
+/**
+ * early_platform_driver_probe_id - probe drivers matching class_str and id
+ * @class_str: string to identify early platform driver class
+ * @id: id to match against
+ * @nr_probe: number of platform devices to successfully probe before exiting
+ */
+static int __init early_platform_driver_probe_id(char *class_str,
+						 int id,
+						 int nr_probe)
+{
+	struct early_platform_driver *epdrv;
+	struct platform_device *match;
+	int match_id;
+	int n = 0;
+	int left = 0;
+
+	list_for_each_entry(epdrv, &early_platform_driver_list, list) {
+		/* only use drivers matching our class_str */
+		if (strcmp(class_str, epdrv->class_str))
+			continue;
+
+		if (id == -2) {
+			match_id = epdrv->requested_id;
+			left = 1;
+
+		} else {
+			match_id = id;
+			left += early_platform_left(epdrv, id);
+
+			/* skip requested id */
+			switch (epdrv->requested_id) {
+			case EARLY_PLATFORM_ID_ERROR:
+			case EARLY_PLATFORM_ID_UNSET:
+				break;
+			default:
+				if (epdrv->requested_id == id)
+					match_id = EARLY_PLATFORM_ID_UNSET;
+			}
+		}
+
+		switch (match_id) {
+		case EARLY_PLATFORM_ID_ERROR:
+			pr_warn("%s: unable to parse %s parameter\n",
+				class_str, epdrv->pdrv->driver.name);
+			/* fall-through */
+		case EARLY_PLATFORM_ID_UNSET:
+			match = NULL;
+			break;
+		default:
+			match = early_platform_match(epdrv, match_id);
+		}
+
+		if (match) {
+			/*
+			 * Set up a sensible init_name to enable
+			 * dev_name() and others to be used before the
+			 * rest of the driver core is initialized.
+			 */
+			if (!match->dev.init_name && slab_is_available()) {
+				if (match->id != -1)
+					match->dev.init_name =
+						kasprintf(GFP_KERNEL, "%s.%d",
+							  match->name,
+							  match->id);
+				else
+					match->dev.init_name =
+						kasprintf(GFP_KERNEL, "%s",
+							  match->name);
+
+				if (!match->dev.init_name)
+					return -ENOMEM;
+			}
+
+			if (epdrv->pdrv->probe(match))
+				pr_warn("%s: unable to probe %s early.\n",
+					class_str, match->name);
+			else
+				n++;
+		}
+
+		if (n >= nr_probe)
+			break;
+	}
+
+	if (left)
+		return n;
+	else
+		return -ENODEV;
+}
+
+/**
+ * early_platform_driver_probe - probe a class of registered drivers
+ * @class_str: string to identify early platform driver class
+ * @nr_probe: number of platform devices to successfully probe before exiting
+ * @user_only: only probe user specified early platform devices
+ *
+ * Used by architecture code to probe registered early platform drivers
+ * within a certain class. For probe to happen a registered early platform
+ * device matching a registered early platform driver is needed.
+ */
+int __init early_platform_driver_probe(char *class_str,
+				       int nr_probe,
+				       int user_only)
+{
+	int k, n, i;
+
+	n = 0;
+	for (i = -2; n < nr_probe; i++) {
+		k = early_platform_driver_probe_id(class_str, i, nr_probe - n);
+
+		if (k < 0)
+			break;
+
+		n += k;
+
+		if (user_only)
+			break;
+	}
+
+	return n;
+}
+
+/**
+ * early_platform_cleanup - clean up early platform code
+ */
+static int __init early_platform_cleanup(void)
+{
+	struct platform_device *pd, *pd2;
+
+	/* clean up the devres list used to chain devices */
+	list_for_each_entry_safe(pd, pd2, &early_platform_device_list,
+				 dev.devres_head) {
+		list_del(&pd->dev.devres_head);
+		memset(&pd->dev.devres_head, 0, sizeof(pd->dev.devres_head));
+	}
+
+	return 0;
+}
+/*
+ * This must happen once after all early devices are probed but before probing
+ * real platform devices.
+ */
+subsys_initcall(early_platform_cleanup);