scsi: ufs: core: mcq: Calculate queue depth

The UFS device defines the supported queuedepth by bqueuedepth which has a
max value of 256.  The HC defines MAC (Max Active Commands) that defines
the max number of commands that in flight to the UFS device.  Calculate and
configure the nutrs based on both these values.
Co-developed-by: Can Guo <quic_cang@quicinc.com>
Signed-off-by: Can Guo <quic_cang@quicinc.com>
Signed-off-by: Asutosh Das <quic_asutoshd@quicinc.com>
Reviewed-by: Manivannan Sadhasivam <mani@kernel.org>
Reviewed-by: Bart Van Assche <bvanassche@acm.org>
Reviewed-by: Stanley Chu <stanley.chu@mediatek.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

drivers/ufs/core/ufs-mcq.c

@@ -19,6 +19,9 @@
 #define UFS_MCQ_NUM_DEV_CMD_QUEUES 1
 #define UFS_MCQ_MIN_POLL_QUEUES 0
 
+#define MAX_DEV_CMD_ENTRIES	2
+#define MCQ_CFG_MAC_MASK	GENMASK(16, 8)
+
 static int rw_queue_count_set(const char *val, const struct kernel_param *kp)
 {
 	return param_set_uint_minmax(val, kp, UFS_MCQ_MIN_RW_QUEUES,
@@ -67,6 +70,38 @@ 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");
 
+/**
+ * ufshcd_mcq_decide_queue_depth - decide the queue depth
+ * @hba - per adapter instance
+ *
+ * Returns queue-depth on success, non-zero on error
+ *
+ * MAC - Max. Active Command of the Host Controller (HC)
+ * HC wouldn't send more than this commands to the device.
+ * It is mandatory to implement get_hba_mac() to enable MCQ mode.
+ * Calculates and adjusts the queue depth based on the depth
+ * supported by the HC and ufs device.
+ */
+int ufshcd_mcq_decide_queue_depth(struct ufs_hba *hba)
+{
+	int mac;
+
+	/* Mandatory to implement get_hba_mac() */
+	mac = ufshcd_mcq_vops_get_hba_mac(hba);
+	if (mac < 0) {
+		dev_err(hba->dev, "Failed to get mac, err=%d\n", mac);
+		return mac;
+	}
+
+	WARN_ON_ONCE(!hba->dev_info.bqueuedepth);
+	/*
+	 * max. value of bqueuedepth = 256, mac is host dependent.
+	 * It is mandatory for UFS device to define bQueueDepth if
+	 * shared queuing architecture is enabled.
+	 */
+	return min_t(int, mac, hba->dev_info.bqueuedepth);
+}
+
 static int ufshcd_mcq_config_nr_queues(struct ufs_hba *hba)
 {
 	int i;

drivers/ufs/core/ufshcd-priv.h

@@ -62,6 +62,7 @@ int ufshcd_query_flag(struct ufs_hba *hba, enum query_opcode opcode,
 	enum flag_idn idn, u8 index, bool *flag_res);
 void ufshcd_auto_hibern8_update(struct ufs_hba *hba, u32 ahit);
 int ufshcd_mcq_init(struct ufs_hba *hba);
+int ufshcd_mcq_decide_queue_depth(struct ufs_hba *hba);
 
 #define SD_ASCII_STD true
 #define SD_RAW false
@@ -238,6 +239,14 @@ static inline int ufshcd_vops_mcq_config_resource(struct ufs_hba *hba)
 	return -EOPNOTSUPP;
 }
 
+static inline int ufshcd_mcq_vops_get_hba_mac(struct ufs_hba *hba)
+{
+	if (hba->vops && hba->vops->get_hba_mac)
+		return hba->vops->get_hba_mac(hba);
+
+	return -EOPNOTSUPP;
+}
+
 extern const struct ufs_pm_lvl_states ufs_pm_lvl_states[];
 
 /**

drivers/ufs/core/ufshcd.c

@@ -7887,6 +7887,7 @@ static int ufs_get_device_desc(struct ufs_hba *hba)
 	/* getting Specification Version in big endian format */
 	dev_info->wspecversion = desc_buf[DEVICE_DESC_PARAM_SPEC_VER] << 8 |
 				      desc_buf[DEVICE_DESC_PARAM_SPEC_VER + 1];
+	dev_info->bqueuedepth = desc_buf[DEVICE_DESC_PARAM_Q_DPTH];
 	b_ufs_feature_sup = desc_buf[DEVICE_DESC_PARAM_UFS_FEAT];
 
 	model_index = desc_buf[DEVICE_DESC_PARAM_PRDCT_NAME];
@@ -8296,7 +8297,21 @@ static int ufshcd_add_lus(struct ufs_hba *hba)
 
 static int ufshcd_alloc_mcq(struct ufs_hba *hba)
 {
-	return ufshcd_mcq_init(hba);
+	int ret;
+	int old_nutrs = hba->nutrs;
+
+	ret = ufshcd_mcq_decide_queue_depth(hba);
+	if (ret < 0)
+		return ret;
+
+	hba->nutrs = ret;
+	ret = ufshcd_mcq_init(hba);
+	if (ret) {
+		hba->nutrs = old_nutrs;
+		return ret;
+	}
+
+	return 0;
 }
 
 static int ufshcd_device_init(struct ufs_hba *hba, bool init_dev_params)

drivers/ufs/host/ufs-qcom.c

@@ -1496,6 +1496,12 @@ static int ufs_qcom_mcq_config_resource(struct ufs_hba *hba)
 	return ret;
 }
 
+static int ufs_qcom_get_hba_mac(struct ufs_hba *hba)
+{
+	/* Qualcomm HC supports up to 64 */
+	return MAX_SUPP_MAC;
+}
+
 /*
  * struct ufs_hba_qcom_vops - UFS QCOM specific variant operations
  *
@@ -1521,6 +1527,7 @@ static const struct ufs_hba_variant_ops ufs_hba_qcom_vops = {
 	.program_key		= ufs_qcom_ice_program_key,
 	.reinit_notify		= ufs_qcom_reinit_notify,
 	.mcq_config_resource	= ufs_qcom_mcq_config_resource,
+	.get_hba_mac		= ufs_qcom_get_hba_mac,
 };
 
 /**

drivers/ufs/host/ufs-qcom.h

@@ -16,6 +16,7 @@
 #define HBRN8_POLL_TOUT_MS      100
 #define DEFAULT_CLK_RATE_HZ     1000000
 #define BUS_VECTOR_NAME_LEN     32
+#define MAX_SUPP_MAC		64
 
 #define UFS_HW_VER_MAJOR_MASK	GENMASK(31, 28)
 #define UFS_HW_VER_MINOR_MASK	GENMASK(27, 16)

include/ufs/ufs.h

@@ -617,6 +617,8 @@ struct ufs_dev_info {
 	u8	*model;
 	u16	wspecversion;
 	u32	clk_gating_wait_us;
+	/* Stores the depth of queue in UFS device */
+	u8	bqueuedepth;
 
 	/* UFS HPB related flag */
 	bool	hpb_enabled;

include/ufs/ufshcd.h

@@ -301,6 +301,7 @@ struct ufs_pwr_mode_info {
  * @event_notify: called to notify important events
  * @reinit_notify: called to notify reinit of UFSHCD during max gear switch
  * @mcq_config_resource: called to configure MCQ platform resources
+ * @get_hba_mac: called to get vendor specific mac value, mandatory for mcq mode
  */
 struct ufs_hba_variant_ops {
 	const char *name;
@@ -341,6 +342,7 @@ struct ufs_hba_variant_ops {
 				enum ufs_event_type evt, void *data);
 	void	(*reinit_notify)(struct ufs_hba *);
 	int	(*mcq_config_resource)(struct ufs_hba *hba);
+	int	(*get_hba_mac)(struct ufs_hba *hba);
 };
 
 /* clock gating state  */

include/ufs/ufshci.h

@@ -57,6 +57,7 @@ enum {
 	REG_UFS_CCAP				= 0x100,
 	REG_UFS_CRYPTOCAP			= 0x104,
 
+	REG_UFS_MCQ_CFG				= 0x380,
 	UFSHCI_CRYPTO_REG_SPACE_SIZE		= 0x400,
 };