Merge tag 'remoteproc-for-3.7' of git://git.kernel.org/pub/scm/linux/kernel/git/ohad/remoteproc

Pull remoteproc update from Ohad Ben-Cohen:

 - Remoteproc Recovery - by Fernando Guzman Lugo

   When a remote processor crash is detected, this mechanism will remove
   all virtio children devices, wait until their drivers let go, hard
   reset the remote processor and reload the firmware (resulting in the
   relevant virtio children devices re-added).  Essentially the entire
   software stack is reset, together with the relevant hardware, so
   users don't have to reset the entire phone.

 - STE Modem driver is added - by Sjur Brændeland

 - OMAP DSP boot address support is added - by Juan Gutierrez

 - A handful of fixes/cleanups - Sjur Brændeland, Dan Carpenter, Emil
   Goode

* tag 'remoteproc-for-3.7' of git://git.kernel.org/pub/scm/linux/kernel/git/ohad/remoteproc:
  remoteproc: Fix use of format specifyer
  remoteproc: fix a potential NULL-dereference on cleanup
  remoteproc: select VIRTIO to avoid build breakage
  remoteproc: return -EFAULT on copy_from_user failure
  remoteproc: snprintf() can return more than was printed
  remoteproc: Add STE modem driver
  remtoteproc: maintain max notifyid
  remoteproc: create a 'recovery' debugfs entry
  remoteproc: add actual recovery implementation
  remoteproc: add rproc_report_crash function to notify rproc crashes
  remoteproc: Add dependency to HAS_DMA
  remoteproc/omap: set bootaddr support

1 files changed, 83 insertions, 2 deletions

diff --git a/drivers/remoteproc/remoteproc_debugfs.c b/drivers/remoteproc/remoteproc_debugfs.c
index 03833850f21..157a5730960 100644
--- a/drivers/remoteproc/remoteproc_debugfs.c
+++ b/drivers/remoteproc/remoteproc_debugfs.c
@@ -28,6 +28,9 @@
 #include <linux/debugfs.h>
 #include <linux/remoteproc.h>
 #include <linux/device.h>
+#include <linux/uaccess.h>
+
+#include "remoteproc_internal.h"
 
 /* remoteproc debugfs parent dir */
 static struct dentry *rproc_dbg;
@@ -79,7 +82,7 @@ static ssize_t rproc_state_read(struct file *filp, char __user *userbuf,
 
 	state = rproc->state > RPROC_LAST ? RPROC_LAST : rproc->state;
 
-	i = snprintf(buf, 30, "%.28s (%d)\n", rproc_state_string[state],
+	i = scnprintf(buf, 30, "%.28s (%d)\n", rproc_state_string[state],
 							rproc->state);
 
 	return simple_read_from_buffer(userbuf, count, ppos, buf, i);
@@ -100,7 +103,7 @@ static ssize_t rproc_name_read(struct file *filp, char __user *userbuf,
 	char buf[100];
 	int i;
 
-	i = snprintf(buf, sizeof(buf), "%.98s\n", rproc->name);
+	i = scnprintf(buf, sizeof(buf), "%.98s\n", rproc->name);
 
 	return simple_read_from_buffer(userbuf, count, ppos, buf, i);
 }
@@ -111,6 +114,82 @@ static const struct file_operations rproc_name_ops = {
 	.llseek	= generic_file_llseek,
 };
 
+/* expose recovery flag via debugfs */
+static ssize_t rproc_recovery_read(struct file *filp, char __user *userbuf,
+				   size_t count, loff_t *ppos)
+{
+	struct rproc *rproc = filp->private_data;
+	char *buf = rproc->recovery_disabled ? "disabled\n" : "enabled\n";
+
+	return simple_read_from_buffer(userbuf, count, ppos, buf, strlen(buf));
+}
+
+/*
+ * By writing to the 'recovery' debugfs entry, we control the behavior of the
+ * recovery mechanism dynamically. The default value of this entry is "enabled".
+ *
+ * The 'recovery' debugfs 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
+rproc_recovery_write(struct file *filp, const char __user *user_buf,
+		     size_t count, loff_t *ppos)
+{
+	struct rproc *rproc = filp->private_data;
+	char buf[10];
+	int ret;
+
+	if (count > sizeof(buf))
+		return count;
+
+	ret = copy_from_user(buf, user_buf, count);
+	if (ret)
+		return -EFAULT;
+
+	/* remove end of line */
+	if (buf[count - 1] == '\n')
+		buf[count - 1] = '\0';
+
+	if (!strncmp(buf, "enabled", count)) {
+		rproc->recovery_disabled = false;
+		/* if rproc has crashed, trigger recovery */
+		if (rproc->state == RPROC_CRASHED)
+			rproc_trigger_recovery(rproc);
+	} else if (!strncmp(buf, "disabled", count)) {
+		rproc->recovery_disabled = true;
+	} else if (!strncmp(buf, "recover", count)) {
+		/* if rproc has crashed, trigger recovery */
+		if (rproc->state == RPROC_CRASHED)
+			rproc_trigger_recovery(rproc);
+	}
+
+	return count;
+}
+
+static const struct file_operations rproc_recovery_ops = {
+	.read = rproc_recovery_read,
+	.write = rproc_recovery_write,
+	.open = simple_open,
+	.llseek = generic_file_llseek,
+};
+
 void rproc_remove_trace_file(struct dentry *tfile)
 {
 	debugfs_remove(tfile);
@@ -154,6 +233,8 @@ void rproc_create_debug_dir(struct rproc *rproc)
 					rproc, &rproc_name_ops);
 	debugfs_create_file("state", 0400, rproc->dbg_dir,
 					rproc, &rproc_state_ops);
+	debugfs_create_file("recovery", 0400, rproc->dbg_dir,
+					rproc, &rproc_recovery_ops);
 }
 
 void __init rproc_init_debugfs(void)