scsi: ufs: mcq: Add completion support of a CQE

Add support for completing requests from Completion Queue.  Some host
controllers support vendor specific registers that provide a bitmap of all
CQs which have at least one completed CQE. Add this support.  The MCQ
specification doesn't provide the Task Tag or its equivalent in the
Completion Queue Entry.  So use an indirect method to find the Task Tag
from the Completion Queue Entry.

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: Bart Van Assche <bvanassche@acm.org>
Reviewed-by: Manivannan Sadhasivam <mani@kernel.org>
Reviewed-by: Stanley Chu <stanley.chu@mediatek.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

3 files changed, 141 insertions, 0 deletions

diff --git a/drivers/ufs/core/ufs-mcq.c b/drivers/ufs/core/ufs-mcq.c
index be84bcef2044..cd10d59c77e0 100644
--- a/drivers/ufs/core/ufs-mcq.c
+++ b/drivers/ufs/core/ufs-mcq.c
@@ -25,6 +25,7 @@
 #define MCQ_CFG_MAC_MASK	GENMASK(16, 8)
 #define MCQ_QCFG_SIZE		0x40
 #define MCQ_ENTRY_SIZE_IN_DWORD	8
+#define CQE_UCD_BA GENMASK_ULL(63, 7)
 
 static int rw_queue_count_set(const char *val, const struct kernel_param *kp)
 {
@@ -236,6 +237,63 @@ static void __iomem *mcq_opr_base(struct ufs_hba *hba,
 	return opr->base + opr->stride * i;
 }
 
+u32 ufshcd_mcq_read_cqis(struct ufs_hba *hba, int i)
+{
+	return readl(mcq_opr_base(hba, OPR_CQIS, i) + REG_CQIS);
+}
+
+void ufshcd_mcq_write_cqis(struct ufs_hba *hba, u32 val, int i)
+{
+	writel(val, mcq_opr_base(hba, OPR_CQIS, i) + REG_CQIS);
+}
+
+/*
+ * Current MCQ specification doesn't provide a Task Tag or its equivalent in
+ * the Completion Queue Entry. Find the Task Tag using an indirect method.
+ */
+static int ufshcd_mcq_get_tag(struct ufs_hba *hba,
+				     struct ufs_hw_queue *hwq,
+				     struct cq_entry *cqe)
+{
+	u64 addr;
+
+	/* sizeof(struct utp_transfer_cmd_desc) must be a multiple of 128 */
+	BUILD_BUG_ON(sizeof(struct utp_transfer_cmd_desc) & GENMASK(6, 0));
+
+	/* Bits 63:7 UCD base address, 6:5 are reserved, 4:0 is SQ ID */
+	addr = (le64_to_cpu(cqe->command_desc_base_addr) & CQE_UCD_BA) -
+		hba->ucdl_dma_addr;
+
+	return div_u64(addr, sizeof(struct utp_transfer_cmd_desc));
+}
+
+static void ufshcd_mcq_process_cqe(struct ufs_hba *hba,
+					    struct ufs_hw_queue *hwq)
+{
+	struct cq_entry *cqe = ufshcd_mcq_cur_cqe(hwq);
+	int tag = ufshcd_mcq_get_tag(hba, hwq, cqe);
+
+	ufshcd_compl_one_cqe(hba, tag, cqe);
+}
+
+unsigned long ufshcd_mcq_poll_cqe_nolock(struct ufs_hba *hba,
+					 struct ufs_hw_queue *hwq)
+{
+	unsigned long completed_reqs = 0;
+
+	ufshcd_mcq_update_cq_tail_slot(hwq);
+	while (!ufshcd_mcq_is_cq_empty(hwq)) {
+		ufshcd_mcq_process_cqe(hba, hwq);
+		ufshcd_mcq_inc_cq_head_slot(hwq);
+		completed_reqs++;
+	}
+
+	if (completed_reqs)
+		ufshcd_mcq_update_cq_head(hwq);
+
+	return completed_reqs;
+}
+
 void ufshcd_mcq_make_queues_operational(struct ufs_hba *hba)
 {
 	struct ufs_hw_queue *hwq;
@@ -279,6 +337,9 @@ void ufshcd_mcq_make_queues_operational(struct ufs_hba *hba)
 		hwq->mcq_cq_head = mcq_opr_base(hba, OPR_CQD, i) + REG_CQHP;
 		hwq->mcq_cq_tail = mcq_opr_base(hba, OPR_CQD, i) + REG_CQTP;
 
+		/* Reinitializing is needed upon HC reset */
+		hwq->sq_tail_slot = hwq->cq_tail_slot = hwq->cq_head_slot = 0;
+
 		/* Enable Tail Entry Push Status interrupt only for non-poll queues */
 		if (i < hba->nr_hw_queues - hba->nr_queues[HCTX_TYPE_POLL])
 			writel(1, mcq_opr_base(hba, OPR_CQIS, i) + REG_CQIE);
diff --git a/drivers/ufs/core/ufshcd-priv.h b/drivers/ufs/core/ufshcd-priv.h
index e87ce19ac896..583fb862013e 100644
--- a/drivers/ufs/core/ufshcd-priv.h
+++ b/drivers/ufs/core/ufshcd-priv.h
@@ -69,6 +69,10 @@ int ufshcd_mcq_memory_alloc(struct ufs_hba *hba);
 void ufshcd_mcq_make_queues_operational(struct ufs_hba *hba);
 void ufshcd_mcq_config_mac(struct ufs_hba *hba, u32 max_active_cmds);
 void ufshcd_mcq_select_mcq_mode(struct ufs_hba *hba);
+u32 ufshcd_mcq_read_cqis(struct ufs_hba *hba, int i);
+void ufshcd_mcq_write_cqis(struct ufs_hba *hba, u32 val, int i);
+unsigned long ufshcd_mcq_poll_cqe_nolock(struct ufs_hba *hba,
+					 struct ufs_hw_queue *hwq);
 struct ufs_hw_queue *ufshcd_mcq_req_to_hwq(struct ufs_hba *hba,
 					   struct request *req);
 
@@ -264,6 +268,15 @@ static inline int ufshcd_mcq_vops_op_runtime_config(struct ufs_hba *hba)
 	return -EOPNOTSUPP;
 }
 
+static inline int ufshcd_vops_get_outstanding_cqs(struct ufs_hba *hba,
+						  unsigned long *ocqs)
+{
+	if (hba->vops && hba->vops->get_outstanding_cqs)
+		return hba->vops->get_outstanding_cqs(hba, ocqs);
+
+	return -EOPNOTSUPP;
+}
+
 extern const struct ufs_pm_lvl_states ufs_pm_lvl_states[];
 
 /**
@@ -350,4 +363,34 @@ static inline void ufshcd_inc_sq_tail(struct ufs_hw_queue *q)
 	writel(val, q->mcq_sq_tail);
 }
 
+static inline void ufshcd_mcq_update_cq_tail_slot(struct ufs_hw_queue *q)
+{
+	u32 val = readl(q->mcq_cq_tail);
+
+	q->cq_tail_slot = val / sizeof(struct cq_entry);
+}
+
+static inline bool ufshcd_mcq_is_cq_empty(struct ufs_hw_queue *q)
+{
+	return q->cq_head_slot == q->cq_tail_slot;
+}
+
+static inline void ufshcd_mcq_inc_cq_head_slot(struct ufs_hw_queue *q)
+{
+	q->cq_head_slot++;
+	if (q->cq_head_slot == q->max_entries)
+		q->cq_head_slot = 0;
+}
+
+static inline void ufshcd_mcq_update_cq_head(struct ufs_hw_queue *q)
+{
+	writel(q->cq_head_slot * sizeof(struct cq_entry), q->mcq_cq_head);
+}
+
+static inline struct cq_entry *ufshcd_mcq_cur_cqe(struct ufs_hw_queue *q)
+{
+	struct cq_entry *cqe = q->cqe_base_addr;
+
+	return cqe + q->cq_head_slot;
+}
 #endif /* _UFSHCD_PRIV_H_ */
diff --git a/drivers/ufs/core/ufshcd.c b/drivers/ufs/core/ufshcd.c
index 34947379320f..3afa07683ecf 100644
--- a/drivers/ufs/core/ufshcd.c
+++ b/drivers/ufs/core/ufshcd.c
@@ -6684,6 +6684,40 @@ static irqreturn_t ufshcd_tmc_handler(struct ufs_hba *hba)
 }
 
 /**
+ * ufshcd_handle_mcq_cq_events - handle MCQ completion queue events
+ * @hba: per adapter instance
+ *
+ * Returns IRQ_HANDLED if interrupt is handled
+ */
+static irqreturn_t ufshcd_handle_mcq_cq_events(struct ufs_hba *hba)
+{
+	struct ufs_hw_queue *hwq;
+	unsigned long outstanding_cqs;
+	unsigned int nr_queues;
+	int i, ret;
+	u32 events;
+
+	ret = ufshcd_vops_get_outstanding_cqs(hba, &outstanding_cqs);
+	if (ret)
+		outstanding_cqs = (1U << hba->nr_hw_queues) - 1;
+
+	/* Exclude the poll queues */
+	nr_queues = hba->nr_hw_queues - hba->nr_queues[HCTX_TYPE_POLL];
+	for_each_set_bit(i, &outstanding_cqs, nr_queues) {
+		hwq = &hba->uhq[i];
+
+		events = ufshcd_mcq_read_cqis(hba, i);
+		if (events)
+			ufshcd_mcq_write_cqis(hba, events, i);
+
+		if (events & UFSHCD_MCQ_CQIS_TAIL_ENT_PUSH_STS)
+			ufshcd_mcq_poll_cqe_nolock(hba, hwq);
+	}
+
+	return IRQ_HANDLED;
+}
+
+/**
  * ufshcd_sl_intr - Interrupt service routine
  * @hba: per adapter instance
  * @intr_status: contains interrupts generated by the controller
@@ -6708,6 +6742,9 @@ static irqreturn_t ufshcd_sl_intr(struct ufs_hba *hba, u32 intr_status)
 	if (intr_status & UTP_TRANSFER_REQ_COMPL)
 		retval |= ufshcd_transfer_req_compl(hba);
 
+	if (intr_status & MCQ_CQ_EVENT_STATUS)
+		retval |= ufshcd_handle_mcq_cq_events(hba);
+
 	return retval;
 }