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From:   Rishabh Bhatnagar <rishabhb@codeaurora.org>
To:     linux-remoteproc@vger.kernel.org, linux-kernel@vger.kernel.org
Cc:     bjorn.andersson@linaro.org, ohad@wizery.com,
        mathieu.poirier@linaro.org, tsoni@codeaurora.org,
        psodagud@codeaurora.org, sidgup@codeaurora.org,
        Rishabh Bhatnagar <rishabhb@codeaurora.org>
Subject: [PATCH 3/3] remoteproc: Add coredump sysfs attribute
Date:   Thu, 16 Apr 2020 11:38:32 -0700
Message-Id: <1587062312-4939-3-git-send-email-rishabhb@codeaurora.org>
In-Reply-To: <1587062312-4939-1-git-send-email-rishabhb@codeaurora.org>
References: <1587062312-4939-1-git-send-email-rishabhb@codeaurora.org>
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

Add coredump sysfs attribute to configure the type of memory dump.
User can select between default or inline coredump functionality.
Also coredump collection can be disabled through this interface.
This functionality can be configured differently for different
remote processors.
This provides an option to dynamically configure the dump type
based on userpsace capability.

Signed-off-by: Rishabh Bhatnagar <rishabhb@codeaurora.org>
---
 drivers/remoteproc/remoteproc_sysfs.c | 57 +++++++++++++++++++++++++++++++++++
 1 file changed, 57 insertions(+)

diff --git a/drivers/remoteproc/remoteproc_sysfs.c b/drivers/remoteproc/remoteproc_sysfs.c
index 7f8536b..d112664 100644
--- a/drivers/remoteproc/remoteproc_sysfs.c
+++ b/drivers/remoteproc/remoteproc_sysfs.c
@@ -9,6 +9,62 @@
 
 #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_conf
+ */
+static const char * const rproc_coredump_str[] = {
+	[COREDUMP_DEFAULT]	= "default",
+	[COREDUMP_INLINE]	= "inline",
+	[COREDUMP_DISABLED]	= "disabled",
+};
+
+/* Expose the current coredump configuration via sysfs */
+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->coredump_conf]);
+}
+
+/* Change the coredump configuration via sysfs */
+static ssize_t coredump_store(struct device *dev, struct device_attribute *attr,
+			       const char *buf, size_t count)
+{
+	struct rproc *rproc = to_rproc(dev);
+	int err;
+
+	err = mutex_lock_interruptible(&rproc->lock);
+	if (err) {
+		dev_err(dev, "can't lock rproc %s: %d\n", rproc->name, err);
+		return -EINVAL;
+	}
+
+	if (rproc->state == RPROC_CRASHED) {
+		dev_err(dev, "can't change coredump configuration\n");
+		err = -EBUSY;
+		goto out;
+	}
+
+	if (sysfs_streq(buf, "disable"))
+		rproc->coredump_conf = COREDUMP_DISABLED;
+	else if (sysfs_streq(buf, "inline"))
+		rproc->coredump_conf = COREDUMP_INLINE;
+	else if (sysfs_streq(buf, "default"))
+		rproc->coredump_conf = COREDUMP_DEFAULT;
+	else {
+		dev_err(dev, "Invalid coredump configuration\n");
+		err = -EINVAL;
+	}
+out:
+	mutex_unlock(&rproc->lock);
+
+	return err ? err : 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)
@@ -127,6 +183,7 @@ static ssize_t name_show(struct device *dev, struct device_attribute *attr,
 	&dev_attr_firmware.attr,
 	&dev_attr_state.attr,
 	&dev_attr_name.attr,
+	&dev_attr_coredump.attr,
 	NULL
 };
 
-- 
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