1 files changed, 146 insertions, 92 deletions

diff --git a/drivers/gpio/gpio-sim.c b/drivers/gpio/gpio-sim.c
index f387dad81f29..a83f5238427c 100644
--- a/drivers/gpio/gpio-sim.c
+++ b/drivers/gpio/gpio-sim.c
@@ -10,7 +10,6 @@
 #include <linux/array_size.h>
 #include <linux/bitmap.h>
 #include <linux/cleanup.h>
-#include <linux/completion.h>
 #include <linux/configfs.h>
 #include <linux/device.h>
 #include <linux/err.h>
@@ -37,8 +36,10 @@
 #include <linux/sysfs.h>
 #include <linux/types.h>
 
+#include "dev-sync-probe.h"
+
 #define GPIO_SIM_NGPIO_MAX	1024
-#define GPIO_SIM_PROP_MAX	4 /* Max 3 properties + sentinel. */
+#define GPIO_SIM_PROP_MAX	5 /* Max 4 properties + sentinel. */
 #define GPIO_SIM_NUM_ATTRS	3 /* value, pull and sentinel */
 
 static DEFINE_IDA(gpio_sim_ida);
@@ -119,12 +120,14 @@ static int gpio_sim_get(struct gpio_chip *gc, unsigned int offset)
 	return !!test_bit(offset, chip->value_map);
 }
 
-static void gpio_sim_set(struct gpio_chip *gc, unsigned int offset, int value)
+static int gpio_sim_set(struct gpio_chip *gc, unsigned int offset, int value)
 {
 	struct gpio_sim_chip *chip = gpiochip_get_data(gc);
 
 	scoped_guard(mutex, &chip->lock)
 		__assign_bit(offset, chip->value_map, value);
+
+	return 0;
 }
 
 static int gpio_sim_get_multiple(struct gpio_chip *gc,
@@ -138,14 +141,16 @@ static int gpio_sim_get_multiple(struct gpio_chip *gc,
 	return 0;
 }
 
-static void gpio_sim_set_multiple(struct gpio_chip *gc,
-				  unsigned long *mask, unsigned long *bits)
+static int gpio_sim_set_multiple(struct gpio_chip *gc,
+				 unsigned long *mask, unsigned long *bits)
 {
 	struct gpio_sim_chip *chip = gpiochip_get_data(gc);
 
 	scoped_guard(mutex, &chip->lock)
 		bitmap_replace(chip->value_map, chip->value_map, bits, mask,
 			       gc->ngpio);
+
+	return 0;
 }
 
 static int gpio_sim_direction_output(struct gpio_chip *gc,
@@ -257,8 +262,7 @@ static void gpio_sim_dbg_show(struct seq_file *seq, struct gpio_chip *gc)
 	guard(mutex)(&chip->lock);
 
 	for_each_hwgpio(gc, i, label)
-		seq_printf(seq, " gpio-%-3d (%s) %s,%s\n",
-			   gc->base + i,
+		seq_printf(seq, " gpio-%-3d (%s) %s,%s\n", i,
 			   label ?: "<unused>",
 			   test_bit(i, chip->direction_map) ? "input" :
 				test_bit(i, chip->value_map) ? "output-high" :
@@ -413,11 +417,6 @@ static int gpio_sim_setup_sysfs(struct gpio_sim_chip *chip)
 	return devm_add_action_or_reset(dev, gpio_sim_sysfs_remove, chip);
 }
 
-static int gpio_sim_dev_match_fwnode(struct device *dev, void *data)
-{
-	return device_match_fwnode(dev, data);
-}
-
 static int gpio_sim_add_bank(struct fwnode_handle *swnode, struct device *dev)
 {
 	struct gpio_sim_chip *chip;
@@ -503,7 +502,7 @@ static int gpio_sim_add_bank(struct fwnode_handle *swnode, struct device *dev)
 	if (ret)
 		return ret;
 
-	chip->dev = device_find_child(dev, swnode, gpio_sim_dev_match_fwnode);
+	chip->dev = device_find_child(dev, swnode, device_match_fwnode);
 	if (!chip->dev)
 		return -ENODEV;
 
@@ -546,14 +545,9 @@ static struct platform_driver gpio_sim_driver = {
 };
 
 struct gpio_sim_device {
+	struct dev_sync_probe_data probe_data;
 	struct config_group group;
 
-	/*
-	 * If pdev is NULL, the device is 'pending' (waiting for configuration).
-	 * Once the pointer is assigned, the device has been created and the
-	 * item is 'live'.
-	 */
-	struct platform_device *pdev;
 	int id;
 
 	/*
@@ -567,46 +561,11 @@ struct gpio_sim_device {
 	 */
 	struct mutex lock;
 
-	/*
-	 * This is used to synchronously wait for the driver's probe to complete
-	 * and notify the user-space about any errors.
-	 */
-	struct notifier_block bus_notifier;
-	struct completion probe_completion;
-	bool driver_bound;
-
 	struct gpiod_hog *hogs;
 
 	struct list_head bank_list;
 };
 
-/* This is called with dev->lock already taken. */
-static int gpio_sim_bus_notifier_call(struct notifier_block *nb,
-				      unsigned long action, void *data)
-{
-	struct gpio_sim_device *simdev = container_of(nb,
-						      struct gpio_sim_device,
-						      bus_notifier);
-	struct device *dev = data;
-	char devname[32];
-
-	snprintf(devname, sizeof(devname), "gpio-sim.%u", simdev->id);
-
-	if (!device_match_name(dev, devname))
-		return NOTIFY_DONE;
-
-	if (action == BUS_NOTIFY_BOUND_DRIVER)
-		simdev->driver_bound = true;
-	else if (action == BUS_NOTIFY_DRIVER_NOT_BOUND)
-		simdev->driver_bound = false;
-	else
-		return NOTIFY_DONE;
-
-	complete(&simdev->probe_completion);
-
-	return NOTIFY_OK;
-}
-
 static struct gpio_sim_device *to_gpio_sim_device(struct config_item *item)
 {
 	struct config_group *group = to_config_group(item);
@@ -669,6 +628,7 @@ struct gpio_sim_line {
 
 	unsigned int offset;
 	char *name;
+	bool valid;
 
 	/* There can only be one hog per line. */
 	struct gpio_sim_hog *hog;
@@ -713,7 +673,7 @@ static bool gpio_sim_device_is_live(struct gpio_sim_device *dev)
 {
 	lockdep_assert_held(&dev->lock);
 
-	return !!dev->pdev;
+	return !!dev->probe_data.pdev;
 }
 
 static char *gpio_sim_strdup_trimmed(const char *str, size_t count)
@@ -735,7 +695,7 @@ static ssize_t gpio_sim_device_config_dev_name_show(struct config_item *item,
 
 	guard(mutex)(&dev->lock);
 
-	pdev = dev->pdev;
+	pdev = dev->probe_data.pdev;
 	if (pdev)
 		return sprintf(page, "%s\n", dev_name(&pdev->dev));
 
@@ -784,6 +744,36 @@ gpio_sim_set_line_names(struct gpio_sim_bank *bank, char **line_names)
 	}
 }
 
+static unsigned int gpio_sim_get_reserved_ranges_size(struct gpio_sim_bank *bank)
+{
+	struct gpio_sim_line *line;
+	unsigned int size = 0;
+
+	list_for_each_entry(line, &bank->line_list, siblings) {
+		if (line->valid)
+			continue;
+
+		size += 2;
+	}
+
+	return size;
+}
+
+static void gpio_sim_set_reserved_ranges(struct gpio_sim_bank *bank,
+					 u32 *ranges)
+{
+	struct gpio_sim_line *line;
+	int i = 0;
+
+	list_for_each_entry(line, &bank->line_list, siblings) {
+		if (line->valid)
+			continue;
+
+		ranges[i++] = line->offset;
+		ranges[i++] = 1;
+	}
+}
+
 static void gpio_sim_remove_hogs(struct gpio_sim_device *dev)
 {
 	struct gpiod_hog *hog;
@@ -884,9 +874,10 @@ static struct fwnode_handle *
 gpio_sim_make_bank_swnode(struct gpio_sim_bank *bank,
 			  struct fwnode_handle *parent)
 {
+	unsigned int prop_idx = 0, line_names_size, ranges_size;
 	struct property_entry properties[GPIO_SIM_PROP_MAX];
-	unsigned int prop_idx = 0, line_names_size;
 	char **line_names __free(kfree) = NULL;
+	u32 *ranges __free(kfree) = NULL;
 
 	memset(properties, 0, sizeof(properties));
 
@@ -910,6 +901,19 @@ gpio_sim_make_bank_swnode(struct gpio_sim_bank *bank,
 						line_names, line_names_size);
 	}
 
+	ranges_size = gpio_sim_get_reserved_ranges_size(bank);
+	if (ranges_size) {
+		ranges = kcalloc(ranges_size, sizeof(u32), GFP_KERNEL);
+		if (!ranges)
+			return ERR_PTR(-ENOMEM);
+
+		gpio_sim_set_reserved_ranges(bank, ranges);
+
+		properties[prop_idx++] = PROPERTY_ENTRY_U32_ARRAY_LEN(
+						"gpio-reserved-ranges",
+						ranges, ranges_size);
+	}
+
 	return fwnode_create_software_node(properties, parent);
 }
 
@@ -944,7 +948,6 @@ static int gpio_sim_device_activate(struct gpio_sim_device *dev)
 {
 	struct platform_device_info pdevinfo;
 	struct fwnode_handle *swnode;
-	struct platform_device *pdev;
 	struct gpio_sim_bank *bank;
 	int ret;
 
@@ -986,31 +989,13 @@ static int gpio_sim_device_activate(struct gpio_sim_device *dev)
 	pdevinfo.fwnode = swnode;
 	pdevinfo.id = dev->id;
 
-	reinit_completion(&dev->probe_completion);
-	dev->driver_bound = false;
-	bus_register_notifier(&platform_bus_type, &dev->bus_notifier);
-
-	pdev = platform_device_register_full(&pdevinfo);
-	if (IS_ERR(pdev)) {
-		bus_unregister_notifier(&platform_bus_type, &dev->bus_notifier);
-		gpio_sim_remove_hogs(dev);
-		gpio_sim_remove_swnode_recursive(swnode);
-		return PTR_ERR(pdev);
-	}
-
-	wait_for_completion(&dev->probe_completion);
-	bus_unregister_notifier(&platform_bus_type, &dev->bus_notifier);
-
-	if (!dev->driver_bound) {
-		/* Probe failed, check kernel log. */
-		platform_device_unregister(pdev);
+	ret = dev_sync_probe_register(&dev->probe_data, &pdevinfo);
+	if (ret) {
 		gpio_sim_remove_hogs(dev);
 		gpio_sim_remove_swnode_recursive(swnode);
-		return -ENXIO;
+		return ret;
 	}
 
-	dev->pdev = pdev;
-
 	return 0;
 }
 
@@ -1020,11 +1005,37 @@ static void gpio_sim_device_deactivate(struct gpio_sim_device *dev)
 
 	lockdep_assert_held(&dev->lock);
 
-	swnode = dev_fwnode(&dev->pdev->dev);
-	platform_device_unregister(dev->pdev);
+	swnode = dev_fwnode(&dev->probe_data.pdev->dev);
+	dev_sync_probe_unregister(&dev->probe_data);
 	gpio_sim_remove_hogs(dev);
 	gpio_sim_remove_swnode_recursive(swnode);
-	dev->pdev = NULL;
+}
+
+static void
+gpio_sim_device_lockup_configfs(struct gpio_sim_device *dev, bool lock)
+{
+	struct configfs_subsystem *subsys = dev->group.cg_subsys;
+	struct gpio_sim_bank *bank;
+	struct gpio_sim_line *line;
+	struct config_item *item;
+
+	/*
+	 * The device only needs to depend on leaf entries. This is
+	 * sufficient to lock up all the configfs entries that the
+	 * instantiated, alive device depends on.
+	 */
+	list_for_each_entry(bank, &dev->bank_list, siblings) {
+		list_for_each_entry(line, &bank->line_list, siblings) {
+			item = line->hog ? &line->hog->item
+					 : &line->group.cg_item;
+
+			if (lock)
+				WARN_ON(configfs_depend_item_unlocked(subsys,
+								      item));
+			else
+				configfs_undepend_item_unlocked(item);
+		}
+	}
 }
 
 static ssize_t
@@ -1039,14 +1050,24 @@ gpio_sim_device_config_live_store(struct config_item *item,
 	if (ret)
 		return ret;
 
-	guard(mutex)(&dev->lock);
+	if (live)
+		gpio_sim_device_lockup_configfs(dev, true);
 
-	if (live == gpio_sim_device_is_live(dev))
-		ret = -EPERM;
-	else if (live)
-		ret = gpio_sim_device_activate(dev);
-	else
-		gpio_sim_device_deactivate(dev);
+	scoped_guard(mutex, &dev->lock) {
+		if (live == gpio_sim_device_is_live(dev))
+			ret = -EPERM;
+		else if (live)
+			ret = gpio_sim_device_activate(dev);
+		else
+			gpio_sim_device_deactivate(dev);
+	}
+
+	/*
+	 * Undepend is required only if device disablement (live == 0)
+	 * succeeds or if device enablement (live == 1) fails.
+	 */
+	if (live == !!ret)
+		gpio_sim_device_lockup_configfs(dev, false);
 
 	return ret ?: count;
 }
@@ -1088,7 +1109,7 @@ static ssize_t gpio_sim_bank_config_chip_name_show(struct config_item *item,
 	guard(mutex)(&dev->lock);
 
 	if (gpio_sim_device_is_live(dev))
-		return device_for_each_child(&dev->pdev->dev, &ctx,
+		return device_for_each_child(&dev->probe_data.pdev->dev, &ctx,
 					     gpio_sim_emit_chip_name);
 
 	return sprintf(page, "none\n");
@@ -1212,8 +1233,41 @@ static ssize_t gpio_sim_line_config_name_store(struct config_item *item,
 
 CONFIGFS_ATTR(gpio_sim_line_config_, name);
 
+static ssize_t
+gpio_sim_line_config_valid_show(struct config_item *item, char *page)
+{
+	struct gpio_sim_line *line = to_gpio_sim_line(item);
+	struct gpio_sim_device *dev = gpio_sim_line_get_device(line);
+
+	guard(mutex)(&dev->lock);
+
+	return sprintf(page, "%c\n", line->valid ? '1' : '0');
+}
+
+static ssize_t gpio_sim_line_config_valid_store(struct config_item *item,
+						const char *page, size_t count)
+{
+	struct gpio_sim_line *line = to_gpio_sim_line(item);
+	struct gpio_sim_device *dev = gpio_sim_line_get_device(line);
+	bool valid;
+	int ret;
+
+	ret = kstrtobool(page, &valid);
+	if (ret)
+		return ret;
+
+	guard(mutex)(&dev->lock);
+
+	line->valid = valid;
+
+	return count;
+}
+
+CONFIGFS_ATTR(gpio_sim_line_config_, valid);
+
 static struct configfs_attribute *gpio_sim_line_config_attrs[] = {
 	&gpio_sim_line_config_attr_name,
+	&gpio_sim_line_config_attr_valid,
 	NULL
 };
 
@@ -1422,6 +1476,7 @@ gpio_sim_bank_config_make_line_group(struct config_group *group,
 
 	line->parent = bank;
 	line->offset = offset;
+	line->valid = true;
 	list_add_tail(&line->siblings, &bank->line_list);
 
 	return &line->group;
@@ -1529,8 +1584,7 @@ gpio_sim_config_make_device_group(struct config_group *group, const char *name)
 	mutex_init(&dev->lock);
 	INIT_LIST_HEAD(&dev->bank_list);
 
-	dev->bus_notifier.notifier_call = gpio_sim_bus_notifier_call;
-	init_completion(&dev->probe_completion);
+	dev_sync_probe_init(&dev->probe_data);
 
 	return &no_free_ptr(dev)->group;
 }