1 files changed, 165 insertions, 47 deletions

diff --git a/drivers/remoteproc/remoteproc_sysfs.c b/drivers/remoteproc/remoteproc_sysfs.c
index 3a4c3d7cafca..138e752c5e4e 100644
--- a/drivers/remoteproc/remoteproc_sysfs.c
+++ b/drivers/remoteproc/remoteproc_sysfs.c
@@ -1,69 +1,159 @@
+// SPDX-License-Identifier: GPL-2.0-only
 /*
  * Remote Processor Framework
- *
- * This program is free software; you can redistribute it and/or
- * modify it under the terms of the GNU General Public License
- * version 2 as published by the Free Software Foundation.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- * GNU General Public License for more details.
  */
 
 #include <linux/remoteproc.h>
+#include <linux/slab.h>
 
 #include "remoteproc_internal.h"
 
 #define to_rproc(d) container_of(d, struct rproc, dev)
 
-/* Expose the loaded / running firmware name via sysfs */
-static ssize_t firmware_show(struct device *dev, struct device_attribute *attr,
-			  char *buf)
+static ssize_t recovery_show(struct device *dev,
+			     struct device_attribute *attr, char *buf)
 {
 	struct rproc *rproc = to_rproc(dev);
 
-	return sprintf(buf, "%s\n", rproc->firmware);
+	return sysfs_emit(buf, "%s", rproc->recovery_disabled ? "disabled\n" : "enabled\n");
 }
 
-/* Change firmware name via sysfs */
-static ssize_t firmware_store(struct device *dev,
+/*
+ * By writing to the 'recovery' sysfs entry, we control the behavior of the
+ * recovery mechanism dynamically. The default value of this entry is "enabled".
+ *
+ * The 'recovery' sysfs entry supports these commands:
+ *
+ * enabled:	When enabled, the remote processor will be automatically
+ *		recovered whenever it crashes. Moreover, if the remote
+ *		processor crashes while recovery is disabled, it will
+ *		be automatically recovered too as soon as recovery is enabled.
+ *
+ * disabled:	When disabled, a remote processor will remain in a crashed
+ *		state if it crashes. This is useful for debugging purposes;
+ *		without it, debugging a crash is substantially harder.
+ *
+ * recover:	This function will trigger an immediate recovery if the
+ *		remote processor is in a crashed state, without changing
+ *		or checking the recovery state (enabled/disabled).
+ *		This is useful during debugging sessions, when one expects
+ *		additional crashes to happen after enabling recovery. In this
+ *		case, enabling recovery will make it hard to debug subsequent
+ *		crashes, so it's recommended to keep recovery disabled, and
+ *		instead use the "recover" command as needed.
+ */
+static ssize_t recovery_store(struct device *dev,
 			      struct device_attribute *attr,
 			      const char *buf, size_t count)
 {
 	struct rproc *rproc = to_rproc(dev);
-	char *p;
-	int err, len = count;
 
-	err = mutex_lock_interruptible(&rproc->lock);
-	if (err) {
-		dev_err(dev, "can't lock rproc %s: %d\n", rproc->name, err);
+	if (sysfs_streq(buf, "enabled")) {
+		/* change the flag and begin the recovery process if needed */
+		rproc->recovery_disabled = false;
+		rproc_trigger_recovery(rproc);
+	} else if (sysfs_streq(buf, "disabled")) {
+		rproc->recovery_disabled = true;
+	} else if (sysfs_streq(buf, "recover")) {
+		/* begin the recovery process without changing the flag */
+		rproc_trigger_recovery(rproc);
+	} else {
 		return -EINVAL;
 	}
 
-	if (rproc->state != RPROC_OFFLINE) {
-		dev_err(dev, "can't change firmware while running\n");
-		err = -EBUSY;
-		goto out;
-	}
+	return count;
+}
+static DEVICE_ATTR_RW(recovery);
 
-	len = strcspn(buf, "\n");
-	if (!len) {
-		dev_err(dev, "can't provide a NULL firmware\n");
-		err = -EINVAL;
-		goto out;
+/*
+ * A coredump-configuration-to-string lookup table, for exposing a
+ * human readable configuration via sysfs. Always keep in sync with
+ * enum rproc_coredump_mechanism
+ */
+static const char * const rproc_coredump_str[] = {
+	[RPROC_COREDUMP_DISABLED]	= "disabled",
+	[RPROC_COREDUMP_ENABLED]	= "enabled",
+	[RPROC_COREDUMP_INLINE]		= "inline",
+};
+
+/* Expose the current coredump configuration via debugfs */
+static ssize_t coredump_show(struct device *dev,
+			     struct device_attribute *attr, char *buf)
+{
+	struct rproc *rproc = to_rproc(dev);
+
+	return sysfs_emit(buf, "%s\n", rproc_coredump_str[rproc->dump_conf]);
+}
+
+/*
+ * By writing to the 'coredump' sysfs entry, we control the behavior of the
+ * coredump mechanism dynamically. The default value of this entry is "default".
+ *
+ * The 'coredump' sysfs entry supports these commands:
+ *
+ * disabled:	This is the default coredump mechanism. Recovery will proceed
+ *		without collecting any dump.
+ *
+ * default:	When the remoteproc crashes the entire coredump will be
+ *		copied to a separate buffer and exposed to userspace.
+ *
+ * inline:	The coredump will not be copied to a separate buffer and the
+ *		recovery process will have to wait until data is read by
+ *		userspace. But this avoid usage of extra memory.
+ */
+static ssize_t coredump_store(struct device *dev,
+			      struct device_attribute *attr,
+			      const char *buf, size_t count)
+{
+	struct rproc *rproc = to_rproc(dev);
+
+	if (rproc->state == RPROC_CRASHED) {
+		dev_err(&rproc->dev, "can't change coredump configuration\n");
+		return -EBUSY;
 	}
 
-	p = kstrndup(buf, len, GFP_KERNEL);
-	if (!p) {
-		err = -ENOMEM;
-		goto out;
+	if (sysfs_streq(buf, "disabled")) {
+		rproc->dump_conf = RPROC_COREDUMP_DISABLED;
+	} else if (sysfs_streq(buf, "enabled")) {
+		rproc->dump_conf = RPROC_COREDUMP_ENABLED;
+	} else if (sysfs_streq(buf, "inline")) {
+		rproc->dump_conf = RPROC_COREDUMP_INLINE;
+	} else {
+		dev_err(&rproc->dev, "Invalid coredump configuration\n");
+		return -EINVAL;
 	}
 
-	kfree(rproc->firmware);
-	rproc->firmware = p;
-out:
-	mutex_unlock(&rproc->lock);
+	return count;
+}
+static DEVICE_ATTR_RW(coredump);
+
+/* Expose the loaded / running firmware name via sysfs */
+static ssize_t firmware_show(struct device *dev, struct device_attribute *attr,
+			  char *buf)
+{
+	struct rproc *rproc = to_rproc(dev);
+	const char *firmware = rproc->firmware;
+
+	/*
+	 * If the remote processor has been started by an external
+	 * entity we have no idea of what image it is running.  As such
+	 * simply display a generic string rather then rproc->firmware.
+	 */
+	if (rproc->state == RPROC_ATTACHED)
+		firmware = "unknown";
+
+	return sprintf(buf, "%s\n", firmware);
+}
+
+/* Change firmware name via sysfs */
+static ssize_t firmware_store(struct device *dev,
+			      struct device_attribute *attr,
+			      const char *buf, size_t count)
+{
+	struct rproc *rproc = to_rproc(dev);
+	int err;
+
+	err = rproc_set_firmware(rproc, buf);
 
 	return err ? err : count;
 }
@@ -79,6 +169,8 @@ static const char * const rproc_state_string[] = {
 	[RPROC_RUNNING]		= "running",
 	[RPROC_CRASHED]		= "crashed",
 	[RPROC_DELETED]		= "deleted",
+	[RPROC_ATTACHED]	= "attached",
+	[RPROC_DETACHED]	= "detached",
 	[RPROC_LAST]		= "invalid",
 };
 
@@ -102,17 +194,13 @@ static ssize_t state_store(struct device *dev,
 	int ret = 0;
 
 	if (sysfs_streq(buf, "start")) {
-		if (rproc->state == RPROC_RUNNING)
-			return -EBUSY;
-
 		ret = rproc_boot(rproc);
 		if (ret)
 			dev_err(&rproc->dev, "Boot failed: %d\n", ret);
 	} else if (sysfs_streq(buf, "stop")) {
-		if (rproc->state != RPROC_RUNNING)
-			return -EINVAL;
-
-		rproc_shutdown(rproc);
+		ret = rproc_shutdown(rproc);
+	} else if (sysfs_streq(buf, "detach")) {
+		ret = rproc_detach(rproc);
 	} else {
 		dev_err(&rproc->dev, "Unrecognised option: %s\n", buf);
 		ret = -EINVAL;
@@ -121,14 +209,44 @@ static ssize_t state_store(struct device *dev,
 }
 static DEVICE_ATTR_RW(state);
 
+/* Expose the name of the remote processor via sysfs */
+static ssize_t name_show(struct device *dev, struct device_attribute *attr,
+			 char *buf)
+{
+	struct rproc *rproc = to_rproc(dev);
+
+	return sprintf(buf, "%s\n", rproc->name);
+}
+static DEVICE_ATTR_RO(name);
+
+static umode_t rproc_is_visible(struct kobject *kobj, struct attribute *attr,
+				int n)
+{
+	struct device *dev = kobj_to_dev(kobj);
+	struct rproc *rproc = to_rproc(dev);
+	umode_t mode = attr->mode;
+
+	if (rproc->sysfs_read_only && (attr == &dev_attr_recovery.attr ||
+				       attr == &dev_attr_firmware.attr ||
+				       attr == &dev_attr_state.attr ||
+				       attr == &dev_attr_coredump.attr))
+		mode = 0444;
+
+	return mode;
+}
+
 static struct attribute *rproc_attrs[] = {
+	&dev_attr_coredump.attr,
+	&dev_attr_recovery.attr,
 	&dev_attr_firmware.attr,
 	&dev_attr_state.attr,
+	&dev_attr_name.attr,
 	NULL
 };
 
 static const struct attribute_group rproc_devgroup = {
-	.attrs = rproc_attrs
+	.attrs = rproc_attrs,
+	.is_visible = rproc_is_visible,
 };
 
 static const struct attribute_group *rproc_devgroups[] = {
@@ -136,7 +254,7 @@ static const struct attribute_group *rproc_devgroups[] = {
 	NULL
 };
 
-struct class rproc_class = {
+const struct class rproc_class = {
 	.name		= "remoteproc",
 	.dev_groups	= rproc_devgroups,
 };