RDMA/bnxt_re: Initialize Doorbell pacing feature

Checks for pacing feature capability and get the doorbell pacing
configuration using FW commands. Allocate a page and initialize
the pacing parameters for the applications. Cleanup the page and
de-initialize the pacing during device removal.

Link: https://lore.kernel.org/r/1689742977-9128-4-git-send-email-selvin.xavier@broadcom.com
Signed-off-by: Chandramohan Akula <chandramohan.akula@broadcom.com>
Signed-off-by: Selvin Xavier <selvin.xavier@broadcom.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>

drivers/infiniband/hw/bnxt_re/bnxt_re.h

@@ -112,6 +112,27 @@ struct bnxt_re_gsi_context {
 #define BNXT_RE_NQ_IDX			1
 #define BNXT_RE_GEN_P5_MAX_VF		64
 
+struct bnxt_re_pacing {
+	u64 dbr_db_fifo_reg_off;
+	void *dbr_page;
+	u64 dbr_bar_addr;
+	u32 pacing_algo_th;
+	u32 do_pacing_save;
+	u32 dbq_pacing_time; /* ms */
+	u32 dbr_def_do_pacing;
+	bool dbr_pacing;
+};
+
+#define BNXT_RE_DBR_PACING_TIME 5 /* ms */
+#define BNXT_RE_PACING_ALGO_THRESHOLD 250 /* Entries in DB FIFO */
+#define BNXT_RE_PACING_ALARM_TH_MULTIPLE 2 /* Multiple of pacing algo threshold */
+/* Default do_pacing value when there is no congestion */
+#define BNXT_RE_DBR_DO_PACING_NO_CONGESTION 0x7F /* 1 in 512 probability */
+#define BNXT_RE_DB_FIFO_ROOM_MASK 0x1FFF8000
+#define BNXT_RE_MAX_FIFO_DEPTH 0x2c00
+#define BNXT_RE_DB_FIFO_ROOM_SHIFT 15
+#define BNXT_RE_GRC_FIFO_REG_BASE 0x2000
+
 struct bnxt_re_dev {
 	struct ib_device		ibdev;
 	struct list_head		list;
@@ -171,6 +192,7 @@ struct bnxt_re_dev {
 	atomic_t nq_alloc_cnt;
 	u32 is_virtfn;
 	u32 num_vfs;
+	struct bnxt_re_pacing pacing;
 };
 
 #define to_bnxt_re_dev(ptr, member)	\

drivers/infiniband/hw/bnxt_re/main.c

@@ -432,9 +432,92 @@ int bnxt_re_hwrm_qcaps(struct bnxt_re_dev *rdev)
 		return rc;
 	cctx->modes.db_push = le32_to_cpu(resp.flags) & FUNC_QCAPS_RESP_FLAGS_WCB_PUSH_MODE;
 
+	cctx->modes.dbr_pacing =
+		le32_to_cpu(resp.flags_ext2) & FUNC_QCAPS_RESP_FLAGS_EXT2_DBR_PACING_EXT_SUPPORTED ?
+		true : false;
 	return 0;
 }
 
+static int bnxt_re_hwrm_dbr_pacing_qcfg(struct bnxt_re_dev *rdev)
+{
+	struct hwrm_func_dbr_pacing_qcfg_output resp = {};
+	struct hwrm_func_dbr_pacing_qcfg_input req = {};
+	struct bnxt_en_dev *en_dev = rdev->en_dev;
+	struct bnxt_qplib_chip_ctx *cctx;
+	struct bnxt_fw_msg fw_msg = {};
+	int rc;
+
+	cctx = rdev->chip_ctx;
+	bnxt_re_init_hwrm_hdr((void *)&req, HWRM_FUNC_DBR_PACING_QCFG);
+	bnxt_re_fill_fw_msg(&fw_msg, (void *)&req, sizeof(req), (void *)&resp,
+			    sizeof(resp), DFLT_HWRM_CMD_TIMEOUT);
+	rc = bnxt_send_msg(en_dev, &fw_msg);
+	if (rc)
+		return rc;
+
+	if ((le32_to_cpu(resp.dbr_stat_db_fifo_reg) &
+	    FUNC_DBR_PACING_QCFG_RESP_DBR_STAT_DB_FIFO_REG_ADDR_SPACE_MASK) ==
+		FUNC_DBR_PACING_QCFG_RESP_DBR_STAT_DB_FIFO_REG_ADDR_SPACE_GRC)
+		cctx->dbr_stat_db_fifo =
+			le32_to_cpu(resp.dbr_stat_db_fifo_reg) &
+			~FUNC_DBR_PACING_QCFG_RESP_DBR_STAT_DB_FIFO_REG_ADDR_SPACE_MASK;
+	return 0;
+}
+
+/* Update the pacing tunable parameters to the default values */
+static void bnxt_re_set_default_pacing_data(struct bnxt_re_dev *rdev)
+{
+	struct bnxt_qplib_db_pacing_data *pacing_data = rdev->qplib_res.pacing_data;
+
+	pacing_data->do_pacing = rdev->pacing.dbr_def_do_pacing;
+	pacing_data->pacing_th = rdev->pacing.pacing_algo_th;
+	pacing_data->alarm_th =
+		pacing_data->pacing_th * BNXT_RE_PACING_ALARM_TH_MULTIPLE;
+}
+
+static int bnxt_re_initialize_dbr_pacing(struct bnxt_re_dev *rdev)
+{
+	if (bnxt_re_hwrm_dbr_pacing_qcfg(rdev))
+		return -EIO;
+
+	/* Allocate a page for app use */
+	rdev->pacing.dbr_page = (void *)__get_free_page(GFP_KERNEL);
+	if (!rdev->pacing.dbr_page)
+		return -ENOMEM;
+
+	memset((u8 *)rdev->pacing.dbr_page, 0, PAGE_SIZE);
+	rdev->qplib_res.pacing_data = (struct bnxt_qplib_db_pacing_data *)rdev->pacing.dbr_page;
+
+	/* MAP HW window 2 for reading db fifo depth */
+	writel(rdev->chip_ctx->dbr_stat_db_fifo & BNXT_GRC_BASE_MASK,
+	       rdev->en_dev->bar0 + BNXT_GRCPF_REG_WINDOW_BASE_OUT + 4);
+	rdev->pacing.dbr_db_fifo_reg_off =
+		(rdev->chip_ctx->dbr_stat_db_fifo & BNXT_GRC_OFFSET_MASK) +
+		 BNXT_RE_GRC_FIFO_REG_BASE;
+	rdev->pacing.dbr_bar_addr =
+		pci_resource_start(rdev->qplib_res.pdev, 0) + rdev->pacing.dbr_db_fifo_reg_off;
+
+	rdev->pacing.pacing_algo_th = BNXT_RE_PACING_ALGO_THRESHOLD;
+	rdev->pacing.dbq_pacing_time = BNXT_RE_DBR_PACING_TIME;
+	rdev->pacing.dbr_def_do_pacing = BNXT_RE_DBR_DO_PACING_NO_CONGESTION;
+	rdev->pacing.do_pacing_save = rdev->pacing.dbr_def_do_pacing;
+	rdev->qplib_res.pacing_data->fifo_max_depth = BNXT_RE_MAX_FIFO_DEPTH;
+	rdev->qplib_res.pacing_data->fifo_room_mask = BNXT_RE_DB_FIFO_ROOM_MASK;
+	rdev->qplib_res.pacing_data->fifo_room_shift = BNXT_RE_DB_FIFO_ROOM_SHIFT;
+	rdev->qplib_res.pacing_data->grc_reg_offset = rdev->pacing.dbr_db_fifo_reg_off;
+	bnxt_re_set_default_pacing_data(rdev);
+	return 0;
+}
+
+static void bnxt_re_deinitialize_dbr_pacing(struct bnxt_re_dev *rdev)
+{
+	if (rdev->pacing.dbr_page)
+		free_page((u64)rdev->pacing.dbr_page);
+
+	rdev->pacing.dbr_page = NULL;
+	rdev->pacing.dbr_pacing = false;
+}
+
 static int bnxt_re_net_ring_free(struct bnxt_re_dev *rdev,
 				 u16 fw_ring_id, int type)
 {
@@ -1217,6 +1300,9 @@ static void bnxt_re_dev_uninit(struct bnxt_re_dev *rdev)
 	if (test_and_clear_bit(BNXT_RE_FLAG_GOT_MSIX, &rdev->flags))
 		rdev->num_msix = 0;
 
+	if (rdev->pacing.dbr_pacing)
+		bnxt_re_deinitialize_dbr_pacing(rdev);
+
 	bnxt_re_destroy_chip_ctx(rdev);
 	if (test_and_clear_bit(BNXT_RE_FLAG_NETDEV_REGISTERED, &rdev->flags))
 		bnxt_unregister_dev(rdev->en_dev);
@@ -1309,6 +1395,16 @@ static int bnxt_re_dev_init(struct bnxt_re_dev *rdev, u8 wqe_mode)
 		goto free_ring;
 	}
 
+	if (bnxt_qplib_dbr_pacing_en(rdev->chip_ctx)) {
+		rc = bnxt_re_initialize_dbr_pacing(rdev);
+		if (!rc) {
+			rdev->pacing.dbr_pacing = true;
+		} else {
+			ibdev_err(&rdev->ibdev,
+				  "DBR pacing disabled with error : %d\n", rc);
+			rdev->pacing.dbr_pacing = false;
+		}
+	}
 	rc = bnxt_qplib_get_dev_attr(&rdev->rcfw, &rdev->dev_attr,
 				     rdev->is_virtfn);
 	if (rc)

drivers/infiniband/hw/bnxt_re/qplib_res.h

@@ -48,6 +48,7 @@ extern const struct bnxt_qplib_gid bnxt_qplib_gid_zero;
 struct bnxt_qplib_drv_modes {
 	u8	wqe_mode;
 	bool db_push;
+	bool dbr_pacing;
 };
 
 struct bnxt_qplib_chip_ctx {
@@ -58,6 +59,17 @@ struct bnxt_qplib_chip_ctx {
 	u16	hwrm_cmd_max_timeout;
 	struct bnxt_qplib_drv_modes modes;
 	u64	hwrm_intf_ver;
+	u32     dbr_stat_db_fifo;
+};
+
+struct bnxt_qplib_db_pacing_data {
+	u32 do_pacing;
+	u32 pacing_th;
+	u32 alarm_th;
+	u32 fifo_max_depth;
+	u32 fifo_room_mask;
+	u32 fifo_room_shift;
+	u32 grc_reg_offset;
 };
 
 #define BNXT_QPLIB_DBR_PF_DB_OFFSET     0x10000
@@ -271,6 +283,7 @@ struct bnxt_qplib_res {
 	struct mutex                    dpi_tbl_lock;
 	bool				prio;
 	bool                            is_vf;
+	struct bnxt_qplib_db_pacing_data *pacing_data;
 };
 
 static inline bool bnxt_qplib_is_chip_gen_p5(struct bnxt_qplib_chip_ctx *cctx)
@@ -467,4 +480,10 @@ static inline bool _is_ext_stats_supported(u16 dev_cap_flags)
 	return dev_cap_flags &
 		CREQ_QUERY_FUNC_RESP_SB_EXT_STATS;
 }
+
+static inline u8 bnxt_qplib_dbr_pacing_en(struct bnxt_qplib_chip_ctx *cctx)
+{
+	return cctx->modes.dbr_pacing;
+}
+
 #endif /* __BNXT_QPLIB_RES_H__ */