[RFC PATCH v1 1/2] ufs: introduce callbacks to get command information

[Kiwoong Kim <kwmad.kim@samsung.com>]

Some SoC specific might need command history for
various reasons, such as stacking command contexts
in system memory to check for debugging in the future
or scaling some DVFS knobs to boost IO throughput.

What you would do with the information could be
variant per SoC vendor.

Signed-off-by: Kiwoong Kim <kwmad.kim@samsung.com>
---
 drivers/scsi/ufs/ufshcd.c | 4 ++++
 drivers/scsi/ufs/ufshcd.h | 8 ++++++++
 2 files changed, 12 insertions(+)

diff --git a/drivers/scsi/ufs/ufshcd.c b/drivers/scsi/ufs/ufshcd.c
index 52abe82..0eae3ce 100644
--- a/drivers/scsi/ufs/ufshcd.c
+++ b/drivers/scsi/ufs/ufshcd.c
@@ -2545,6 +2545,8 @@ static int ufshcd_queuecommand(struct Scsi_Host *host, struct scsi_cmnd *cmd)
 	/* issue command to the controller */
 	spin_lock_irqsave(hba->host->host_lock, flags);
 	ufshcd_vops_setup_xfer_req(hba, tag, true);
+	if (cmd)
+		ufshcd_vops_cmd_log(hba, cmd, 1);
 	ufshcd_send_command(hba, tag);
 out_unlock:
 	spin_unlock_irqrestore(hba->host->host_lock, flags);
@@ -4890,6 +4892,8 @@ static void __ufshcd_transfer_req_compl(struct ufs_hba *hba,
 			/* Mark completed command as NULL in LRB */
 			lrbp->cmd = NULL;
 			lrbp->compl_time_stamp = ktime_get();
+			ufshcd_vops_cmd_log(hba, cmd, 2);
+
 			/* Do not touch lrbp after scsi done */
 			cmd->scsi_done(cmd);
 			__ufshcd_release(hba);
diff --git a/drivers/scsi/ufs/ufshcd.h b/drivers/scsi/ufs/ufshcd.h
index c774012..80c4f0d 100644
--- a/drivers/scsi/ufs/ufshcd.h
+++ b/drivers/scsi/ufs/ufshcd.h
@@ -307,6 +307,7 @@ struct ufs_hba_variant_ops {
 	void	(*config_scaling_param)(struct ufs_hba *hba,
 					struct devfreq_dev_profile *profile,
 					void *data);
+	void	(*cmd_log)(struct ufs_hba *hba, struct scsi_cmnd *cmd, int enter);
 };
 
 /* clock gating state  */
@@ -1137,6 +1138,13 @@ static inline void ufshcd_vops_config_scaling_param(struct ufs_hba *hba,
 		hba->vops->config_scaling_param(hba, profile, data);
 }
 
+static inline void ufshcd_vops_cmd_log(struct ufs_hba *hba,
+					 struct scsi_cmnd *cmd, int enter)
+{
+	if (hba->vops && hba->vops->cmd_log)
+		hba->vops->cmd_log(hba, cmd, enter);
+}
+
 extern struct ufs_pm_lvl_states ufs_pm_lvl_states[];
 
 /*
-- 
2.7.4