[PATCH RESEND 04/13] mfd: cros_ec: Add support for dumping panic information

[Enric Balletbo i Serra]

From: Nicolas Boichat <drink...@chromium.org>

This dumps the EC panic information from the previous reboot.

Similar to the information presented by ectool panicinfo, except
that we do not bother doing any parsing (we should write a small
offline tool for that).

Signed-off-by: Nicolas Boichat <drink...@chromium.org>
Reviewed-by: Guenter Roeck <gro...@chromium.org>
Tested-by: Enric Balletbo i Serra <enric.balle...@collabora.com>
---
 drivers/platform/chrome/cros_ec_debugfs.c | 54 +++++++++++++++++++++++++++++++
 1 file changed, 54 insertions(+)

diff --git a/drivers/platform/chrome/cros_ec_debugfs.c 
b/drivers/platform/chrome/cros_ec_debugfs.c
index f8195bb..8133c33 100644
--- a/drivers/platform/chrome/cros_ec_debugfs.c
+++ b/drivers/platform/chrome/cros_ec_debugfs.c
@@ -47,15 +47,19 @@
  * @log_mutex: mutex to protect circular buffer
  * @log_wq: waitqueue for log readers
  * @log_poll_work: recurring task to poll EC for new console log data
+ * @panicinfo_blob: panicinfo debugfs blob
  */
 struct cros_ec_debugfs {
        struct cros_ec_dev *ec;
        struct dentry *dir;
+       /* EC log */
        struct circ_buf log_buffer;
        struct cros_ec_command *read_msg;
        struct mutex log_mutex;
        wait_queue_head_t log_wq;
        struct delayed_work log_poll_work;
+       /* EC panicinfo */
+       struct debugfs_blob_wrapper panicinfo_blob;
 };
 
 /*
@@ -308,6 +312,52 @@ static void cros_ec_cleanup_console_log(struct 
cros_ec_debugfs *debug_info)
        }
 }
 
+static int cros_ec_create_panicinfo(struct cros_ec_debugfs *debug_info)
+{
+       struct cros_ec_device *ec_dev = debug_info->ec->ec_dev;
+       int ret;
+       struct cros_ec_command *msg;
+       int insize;
+
+       insize = ec_dev->max_response;
+
+       msg = devm_kzalloc(debug_info->ec->dev,
+                       sizeof(*msg) + insize, GFP_KERNEL);
+       if (!msg)
+               return -ENOMEM;
+
+       msg->command = EC_CMD_GET_PANIC_INFO;
+       msg->insize = insize;
+
+       ret = cros_ec_cmd_xfer(ec_dev, msg);
+       if (ret < 0) {
+               dev_warn(debug_info->ec->dev, "Cannot read panicinfo.\n");
+               ret = 0;
+               goto free;
+       }
+
+       /* No panic data */
+       if (ret == 0)
+               goto free;
+
+       debug_info->panicinfo_blob.data = msg->data;
+       debug_info->panicinfo_blob.size = ret;
+
+       if (!debugfs_create_blob("panicinfo",
+                                S_IFREG | S_IRUGO,
+                                debug_info->dir,
+                                &debug_info->panicinfo_blob)) {
+               ret = -ENOMEM;
+               goto free;
+       }
+
+       return 0;
+
+free:
+       devm_kfree(debug_info->ec->dev, msg);
+       return ret;
+}
+
 int cros_ec_debugfs_init(struct cros_ec_dev *ec)
 {
        struct cros_ec_platform *ec_platform = dev_get_platdata(ec->dev);
@@ -324,6 +374,10 @@ int cros_ec_debugfs_init(struct cros_ec_dev *ec)
        if (!debug_info->dir)
                return -ENOMEM;
 
+       ret = cros_ec_create_panicinfo(debug_info);
+       if (ret)
+               goto remove_debugfs;
+
        ret = cros_ec_create_console_log(debug_info);
        if (ret)
                goto remove_debugfs;
-- 
2.9.3