[PATCH] scsi: ufs: core: Make UFS_MCQ_NUM_DEV_CMD_QUEUES a module parameter

[Po-Wen Kao]

A dedicated queue for dev commands is not mandatory, hence let
UFS_MCQ_NUM_DEV_CMD_QUEUES become module parameter `dev_cmd_queues`
to allow sharing first hw queue for dev commands.

Signed-off-by: Po-Wen Kao <powen.kao@xxxxxxxxxxxx>
---
 drivers/ufs/core/ufs-mcq.c     | 35 +++++++++++++++++++++++++++-------
 drivers/ufs/core/ufshcd-priv.h |  2 +-
 drivers/ufs/core/ufshcd.c      |  2 +-
 3 files changed, 30 insertions(+), 9 deletions(-)

diff --git a/drivers/ufs/core/ufs-mcq.c b/drivers/ufs/core/ufs-mcq.c
index 31df052fbc41..911dc1cbe4bb 100644
--- a/drivers/ufs/core/ufs-mcq.c
+++ b/drivers/ufs/core/ufs-mcq.c
@@ -16,7 +16,8 @@
 #define MAX_QUEUE_SUP GENMASK(7, 0)
 #define UFS_MCQ_MIN_RW_QUEUES 2
 #define UFS_MCQ_MIN_READ_QUEUES 0
-#define UFS_MCQ_NUM_DEV_CMD_QUEUES 1
+#define UFS_MCQ_MAX_DEV_CMD_QUEUES 1
+#define UFS_MCQ_MIN_DEV_CMD_QUEUES 0
 #define UFS_MCQ_MIN_POLL_QUEUES 0
 #define QUEUE_EN_OFFSET 31
 #define QUEUE_ID_OFFSET 16
@@ -75,6 +76,23 @@ module_param_cb(poll_queues, &poll_queue_count_ops, &poll_queues, 0644);
 MODULE_PARM_DESC(poll_queues,
 		 "Number of poll queues used for r/w. Default value is 1");
 
+static int dev_cmd_queue_count_set(const char *val, const struct kernel_param *kp)
+{
+	return param_set_uint_minmax(val, kp,
+				     UFS_MCQ_MIN_DEV_CMD_QUEUES,
+				     UFS_MCQ_MAX_DEV_CMD_QUEUES);
+}
+
+static const struct kernel_param_ops dev_cmd_queue_count_ops = {
+	.set = dev_cmd_queue_count_set,
+	.get = param_get_uint,
+};
+
+unsigned int dev_cmd_queues = 1;
+module_param_cb(dev_cmd_queues, &dev_cmd_queue_count_ops, &dev_cmd_queues, 0644);
+MODULE_PARM_DESC(dev_cmd_queues,
+		 "Number of queues used for dev command. Default value is 1");
+
 /**
  * ufshcd_mcq_config_mac - Set the #Max Activ Cmds.
  * @hba: per adapter instance
@@ -109,7 +127,7 @@ struct ufs_hw_queue *ufshcd_mcq_req_to_hwq(struct ufs_hba *hba,
 	u32 hwq = blk_mq_unique_tag_to_hwq(utag);
 
 	/* uhq[0] is used to serve device commands */
-	return &hba->uhq[hwq + UFSHCD_MCQ_IO_QUEUE_OFFSET];
+	return &hba->uhq[hwq + dev_cmd_queues];
 }
 
 /**
@@ -152,7 +170,7 @@ static int ufshcd_mcq_config_nr_queues(struct ufs_hba *hba)
 
 	hba_maxq = FIELD_GET(MAX_QUEUE_SUP, hba->mcq_capabilities);
 
-	tot_queues = UFS_MCQ_NUM_DEV_CMD_QUEUES + read_queues + poll_queues +
+	tot_queues = dev_cmd_queues + read_queues + poll_queues +
 			rw_queues;
 
 	if (hba_maxq < tot_queues) {
@@ -161,7 +179,7 @@ static int ufshcd_mcq_config_nr_queues(struct ufs_hba *hba)
 		return -EOPNOTSUPP;
 	}
 
-	rem = hba_maxq - UFS_MCQ_NUM_DEV_CMD_QUEUES;
+	rem = hba_maxq - dev_cmd_queues;
 
 	if (rw_queues) {
 		hba->nr_queues[HCTX_TYPE_DEFAULT] = rw_queues;
@@ -187,7 +205,7 @@ static int ufshcd_mcq_config_nr_queues(struct ufs_hba *hba)
 	for (i = 0; i < HCTX_MAX_TYPES; i++)
 		host->nr_hw_queues += hba->nr_queues[i];
 
-	hba->nr_hw_queues = host->nr_hw_queues + UFS_MCQ_NUM_DEV_CMD_QUEUES;
+	hba->nr_hw_queues = host->nr_hw_queues + dev_cmd_queues;
 	return 0;
 }
 
@@ -423,8 +441,11 @@ int ufshcd_mcq_init(struct ufs_hba *hba)
 
 	/* The very first HW queue serves device commands */
 	hba->dev_cmd_queue = &hba->uhq[0];
-	/* Give dev_cmd_queue the minimal number of entries */
-	hba->dev_cmd_queue->max_entries = MAX_DEV_CMD_ENTRIES;
+	if (dev_cmd_queues) {
+		/* Give dedicated dev_cmd_queue the minimal number of entries */
+		hba->dev_cmd_queue->max_entries = MAX_DEV_CMD_ENTRIES;
+	}
+
 
 	host->host_tagset = 1;
 	return 0;
diff --git a/drivers/ufs/core/ufshcd-priv.h b/drivers/ufs/core/ufshcd-priv.h
index 529f8507a5e4..bad611ac390e 100644
--- a/drivers/ufs/core/ufshcd-priv.h
+++ b/drivers/ufs/core/ufshcd-priv.h
@@ -78,7 +78,6 @@ struct ufs_hw_queue *ufshcd_mcq_req_to_hwq(struct ufs_hba *hba,
 unsigned long ufshcd_mcq_poll_cqe_lock(struct ufs_hba *hba,
 				       struct ufs_hw_queue *hwq);
 
-#define UFSHCD_MCQ_IO_QUEUE_OFFSET	1
 #define SD_ASCII_STD true
 #define SD_RAW false
 int ufshcd_read_string_desc(struct ufs_hba *hba, u8 desc_index,
@@ -287,6 +286,7 @@ static inline int ufshcd_mcq_vops_config_esi(struct ufs_hba *hba)
 	return -EOPNOTSUPP;
 }
 
+extern unsigned int dev_cmd_queues;
 extern const struct ufs_pm_lvl_states ufs_pm_lvl_states[];
 
 /**
diff --git a/drivers/ufs/core/ufshcd.c b/drivers/ufs/core/ufshcd.c
index acae4e194ec4..f2c62a41bb33 100644
--- a/drivers/ufs/core/ufshcd.c
+++ b/drivers/ufs/core/ufshcd.c
@@ -5513,7 +5513,7 @@ static int ufshcd_poll(struct Scsi_Host *shost, unsigned int queue_num)
 	struct ufs_hw_queue *hwq;
 
 	if (is_mcq_enabled(hba)) {
-		hwq = &hba->uhq[queue_num + UFSHCD_MCQ_IO_QUEUE_OFFSET];
+		hwq = &hba->uhq[queue_num + dev_cmd_queues];
 
 		return ufshcd_mcq_poll_cqe_lock(hba, hwq);
 	}
-- 
2.18.0