remoteproc: Add coredump as part of sysfs interface

Add coredump as part of the sysfs interface. This will
allow usage of this configuration feature in production
devices where access to debugfs might be limited.

Signed-off-by: Rishabh Bhatnagar <rishabhb@codeaurora.org>
Link: https://lore.kernel.org/r/1601662144-5964-3-git-send-email-rishabhb@codeaurora.org
Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>

diff --git a/Documentation/ABI/testing/sysfs-class-remoteproc b/Documentation/ABI/testing/sysfs-class-remoteproc
index 36094fbeb97493b74b6952e3ae0ad8eda5a8ff70..050bd25aaa1508d20fa28e701265f4d38e92d586 100644 (file)
--- a/Documentation/ABI/testing/sysfs-class-remoteproc
+++ b/Documentation/ABI/testing/sysfs-class-remoteproc
@@ -58,3 +58,27 @@ Description: Remote processor name
                Reports the name of the remote processor. This can be used by
                userspace in exactly identifying a remote processor and ease
                up the usage in modifying the 'firmware' or 'state' files.
+
+What:          /sys/class/remoteproc/.../coredump
+Date:          July 2020
+Contact:       Bjorn Andersson <bjorn.andersson@linaro.org>, Ohad Ben-Cohen <ohad@wizery.com>
+Description:   Remote processor coredump configuration
+
+               Reports the coredump configuration of the remote processor,
+               which will be one of:
+
+               "disabled"
+               "enabled"
+               "inline"
+
+               "disabled" means no dump will be collected.
+
+               "enabled" means when the remote processor's coredump is
+               collected it will be copied to a separate buffer and that
+               buffer is exposed to userspace.
+
+               "inline" means when the remote processor's coredump is
+               collected userspace will directly read from the remote
+               processor's device memory. Extra buffer will not be used to
+               copy the dump. Also recovery process will not proceed until
+               all data is read by usersapce.

diff --git a/drivers/remoteproc/remoteproc_sysfs.c b/drivers/remoteproc/remoteproc_sysfs.c
index eea514cec50e755d3aa332ca2ab52b361dbd8fa2..85002715c3ea93f1565a9f707529edaf2e600428 100644 (file)
--- a/drivers/remoteproc/remoteproc_sysfs.c
+++ b/drivers/remoteproc/remoteproc_sysfs.c
@@ -10,6 +10,68 @@
 
 #define to_rproc(d) container_of(d, struct rproc, dev)
 
+/*
+ * 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 sprintf(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;
+       }
+
+       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;
+       }
+
+       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)
@@ -138,6 +200,7 @@ static ssize_t name_show(struct device *dev, struct device_attribute *attr,
 static DEVICE_ATTR_RO(name);
 
 static struct attribute *rproc_attrs[] = {
+       &dev_attr_coredump.attr,
        &dev_attr_firmware.attr,
        &dev_attr_state.attr,
        &dev_attr_name.attr,