scsi: ufs-debugfs: add error state

This change adds support to allow user space query if low level UFS driver
has encountered any error or not, this state can be read/cleared via
debugfs.

Change-Id: I867a4621315108aff17be852cfaadcfa945566a7
Signed-off-by: Subhash Jadavani <subhashj@codeaurora.org>

drivers/scsi/ufs/ufs-debugfs.c

@@ -1,4 +1,4 @@
-/* Copyright (c) 2013-2015, The Linux Foundation. All rights reserved.
+/* Copyright (c) 2013-2016, The Linux Foundation. All rights reserved.
  *
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License version 2 and
@@ -1433,6 +1433,41 @@ static const struct file_operations ufsdbg_reset_controller = {
 	.write		= ufsdbg_reset_controller_write,
 };
 
+static int ufsdbg_clear_err_state(void *data, u64 val)
+{
+	struct ufs_hba *hba = data;
+
+	if (!hba)
+		return -EINVAL;
+
+	/* clear the error state on any write attempt */
+	hba->debugfs_files.err_occurred = false;
+
+	return 0;
+}
+
+static int ufsdbg_read_err_state(void *data, u64 *val)
+{
+	struct ufs_hba *hba = data;
+
+	if (!hba)
+		return -EINVAL;
+
+	*val = hba->debugfs_files.err_occurred ? 1 : 0;
+
+	return 0;
+}
+
+void ufsdbg_set_err_state(struct ufs_hba *hba)
+{
+	hba->debugfs_files.err_occurred = true;
+}
+
+DEFINE_SIMPLE_ATTRIBUTE(ufsdbg_err_state,
+			ufsdbg_read_err_state,
+			ufsdbg_clear_err_state,
+			"%llu\n");
+
 void ufsdbg_add_debugfs(struct ufs_hba *hba)
 {
 	char root_name[sizeof("ufshcd00")];
@@ -1594,6 +1629,16 @@ void ufsdbg_add_debugfs(struct ufs_hba *hba)
 		goto err;
 	}
 
+	hba->debugfs_files.err_state =
+		debugfs_create_file("err_state", S_IRUSR | S_IWUSR,
+			hba->debugfs_files.debugfs_root, hba,
+			&ufsdbg_err_state);
+	if (!hba->debugfs_files.err_state) {
+		dev_err(hba->dev,
+		     "%s: failed create err_state debugfs entry", __func__);
+		goto err;
+	}
+
 	ufsdbg_setup_fault_injection(hba);
 
 	ufshcd_vops_add_debugfs(hba, hba->debugfs_files.debugfs_root);

drivers/scsi/ufs/ufs-debugfs.h

@@ -1,4 +1,4 @@
-/* Copyright (c) 2013-2015, The Linux Foundation. All rights reserved.
+/* Copyright (c) 2013-2016, The Linux Foundation. All rights reserved.
  *
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License version 2 and
@@ -37,6 +37,7 @@ void ufsdbg_add_debugfs(struct ufs_hba *hba);
 void ufsdbg_remove_debugfs(struct ufs_hba *hba);
 void ufsdbg_pr_buf_to_std(struct ufs_hba *hba, int offset, int num_regs,
 				char *str, void *priv);
+void ufsdbg_set_err_state(struct ufs_hba *hba);
 #else
 static inline void ufsdbg_add_debugfs(struct ufs_hba *hba)
 {
@@ -48,6 +49,9 @@ static inline void ufsdbg_pr_buf_to_std(struct ufs_hba *hba, int offset,
 	int num_regs, char *str, void *priv)
 {
 }
+void ufsdbg_set_err_state(struct ufs_hba *hba)
+{
+}
 #endif
 
 #ifdef CONFIG_UFS_FAULT_INJECTION

drivers/scsi/ufs/ufshcd.c

@@ -71,6 +71,7 @@ static int ufshcd_tag_req_type(struct request *rq)
 
 static void ufshcd_update_error_stats(struct ufs_hba *hba, int type)
 {
+	ufsdbg_set_err_state(hba);
 	if (type < UFS_ERR_MAX)
 		hba->ufs_stats.err_stats[type]++;
 }
@@ -2143,6 +2144,9 @@ ufshcd_wait_for_uic_cmd(struct ufs_hba *hba, struct uic_command *uic_cmd)
 	else
 		ret = -ETIMEDOUT;
 
+	if (ret)
+		ufsdbg_set_err_state(hba);
+
 	spin_lock_irqsave(hba->host->host_lock, flags);
 	hba->active_uic_cmd = NULL;
 	spin_unlock_irqrestore(hba->host->host_lock, flags);
@@ -2842,6 +2846,9 @@ static int ufshcd_wait_for_dev_cmd(struct ufs_hba *hba,
 		ufshcd_outstanding_req_clear(hba, lrbp->task_tag);
 	}
 
+	if (err)
+		ufsdbg_set_err_state(hba);
+
 	return err;
 }
 
@@ -3874,6 +3881,9 @@ static int ufshcd_uic_pwr_ctrl(struct ufs_hba *hba, struct uic_command *cmd)
 		ret = (status != PWR_OK) ? status : -1;
 	}
 out:
+	if (ret)
+		ufsdbg_set_err_state(hba);
+
 	ufshcd_save_tstamp_of_last_dme_cmd(hba);
 	spin_lock_irqsave(hba->host->host_lock, flags);
 	hba->active_uic_cmd = NULL;
@@ -4947,6 +4957,11 @@ ufshcd_transfer_rsp_status(struct ufs_hba *hba, struct ufshcd_lrb *lrbp)
 			ocs == OCS_MISMATCH_DATA_BUF_SIZE);
 		ufshcd_print_trs(hba, 1 << lrbp->task_tag, print_prdt);
 	}
+
+	if ((host_byte(result) == DID_ERROR) ||
+	    (host_byte(result) == DID_ABORT))
+		ufsdbg_set_err_state(hba);
+
 	return result;
 }
 
@@ -5532,6 +5547,7 @@ static void ufshcd_err_handler(struct work_struct *work)
 
 	hba = container_of(work, struct ufs_hba, eh_work);
 
+	ufsdbg_set_err_state(hba);
 	pm_runtime_get_sync(hba->dev);
 	ufshcd_hold_all(hba);
 

drivers/scsi/ufs/ufshcd.h

@@ -543,6 +543,8 @@ struct debugfs_files {
 	u32 dme_local_attr_id;
 	u32 dme_peer_attr_id;
 	struct dentry *reset_controller;
+	struct dentry *err_state;
+	bool err_occurred;
 #ifdef CONFIG_UFS_FAULT_INJECTION
 	struct dentry *err_inj_scenario;
 	struct dentry *err_inj_stats;