octeontx2-af: Pause frame configuration at cgx

CGX LMAC, the physical interface can generate pause frames when
internal resources asserts backpressure due to exhaustion.

This patch configures CGX to generate 802.3 pause frames.
Also enabled processing of received pause frames on the line which
will assert backpressure on the internal transmit path.

Also added mailbox handlers for PF drivers to enable or disable
pause frames anytime.

Signed-off-by: Geetha sowjanya <gakula@marvell.com>
Signed-off-by: Sunil Goutham <sgoutham@marvell.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/marvell/octeontx2/af/cgx.c

@@ -367,6 +367,107 @@ int cgx_lmac_tx_enable(void *cgxd, int lmac_id, bool enable)
 	return !!(last & DATA_PKT_TX_EN);
 }
 
+int cgx_lmac_get_pause_frm(void *cgxd, int lmac_id,
+			   u8 *tx_pause, u8 *rx_pause)
+{
+	struct cgx *cgx = cgxd;
+	u64 cfg;
+
+	if (!cgx || lmac_id >= cgx->lmac_count)
+		return -ENODEV;
+
+	cfg = cgx_read(cgx, lmac_id, CGXX_SMUX_RX_FRM_CTL);
+	*rx_pause = !!(cfg & CGX_SMUX_RX_FRM_CTL_CTL_BCK);
+
+	cfg = cgx_read(cgx, lmac_id, CGXX_SMUX_TX_CTL);
+	*tx_pause = !!(cfg & CGX_SMUX_TX_CTL_L2P_BP_CONV);
+	return 0;
+}
+
+int cgx_lmac_set_pause_frm(void *cgxd, int lmac_id,
+			   u8 tx_pause, u8 rx_pause)
+{
+	struct cgx *cgx = cgxd;
+	u64 cfg;
+
+	if (!cgx || lmac_id >= cgx->lmac_count)
+		return -ENODEV;
+
+	cfg = cgx_read(cgx, lmac_id, CGXX_SMUX_RX_FRM_CTL);
+	cfg &= ~CGX_SMUX_RX_FRM_CTL_CTL_BCK;
+	cfg |= rx_pause ? CGX_SMUX_RX_FRM_CTL_CTL_BCK : 0x0;
+	cgx_write(cgx, lmac_id, CGXX_SMUX_RX_FRM_CTL, cfg);
+
+	cfg = cgx_read(cgx, lmac_id, CGXX_SMUX_TX_CTL);
+	cfg &= ~CGX_SMUX_TX_CTL_L2P_BP_CONV;
+	cfg |= tx_pause ? CGX_SMUX_TX_CTL_L2P_BP_CONV : 0x0;
+	cgx_write(cgx, lmac_id, CGXX_SMUX_TX_CTL, cfg);
+
+	cfg = cgx_read(cgx, 0, CGXX_CMR_RX_OVR_BP);
+	if (tx_pause) {
+		cfg &= ~CGX_CMR_RX_OVR_BP_EN(lmac_id);
+	} else {
+		cfg |= CGX_CMR_RX_OVR_BP_EN(lmac_id);
+		cfg &= ~CGX_CMR_RX_OVR_BP_BP(lmac_id);
+	}
+	cgx_write(cgx, 0, CGXX_CMR_RX_OVR_BP, cfg);
+	return 0;
+}
+
+static void cgx_lmac_pause_frm_config(struct cgx *cgx, int lmac_id, bool enable)
+{
+	u64 cfg;
+
+	if (!cgx || lmac_id >= cgx->lmac_count)
+		return;
+	if (enable) {
+		/* Enable receive pause frames */
+		cfg = cgx_read(cgx, lmac_id, CGXX_SMUX_RX_FRM_CTL);
+		cfg |= CGX_SMUX_RX_FRM_CTL_CTL_BCK;
+		cgx_write(cgx, lmac_id, CGXX_SMUX_RX_FRM_CTL, cfg);
+
+		cfg = cgx_read(cgx, lmac_id, CGXX_GMP_GMI_RXX_FRM_CTL);
+		cfg |= CGX_GMP_GMI_RXX_FRM_CTL_CTL_BCK;
+		cgx_write(cgx, lmac_id, CGXX_GMP_GMI_RXX_FRM_CTL, cfg);
+
+		/* Enable pause frames transmission */
+		cfg = cgx_read(cgx, lmac_id, CGXX_SMUX_TX_CTL);
+		cfg |= CGX_SMUX_TX_CTL_L2P_BP_CONV;
+		cgx_write(cgx, lmac_id, CGXX_SMUX_TX_CTL, cfg);
+
+		/* Set pause time and interval */
+		cgx_write(cgx, lmac_id, CGXX_SMUX_TX_PAUSE_PKT_TIME,
+			  DEFAULT_PAUSE_TIME);
+		cfg = cgx_read(cgx, lmac_id, CGXX_SMUX_TX_PAUSE_PKT_INTERVAL);
+		cfg &= ~0xFFFFULL;
+		cgx_write(cgx, lmac_id, CGXX_SMUX_TX_PAUSE_PKT_INTERVAL,
+			  cfg | (DEFAULT_PAUSE_TIME / 2));
+
+		cgx_write(cgx, lmac_id, CGXX_GMP_GMI_TX_PAUSE_PKT_TIME,
+			  DEFAULT_PAUSE_TIME);
+
+		cfg = cgx_read(cgx, lmac_id,
+			       CGXX_GMP_GMI_TX_PAUSE_PKT_INTERVAL);
+		cfg &= ~0xFFFFULL;
+		cgx_write(cgx, lmac_id, CGXX_GMP_GMI_TX_PAUSE_PKT_INTERVAL,
+			  cfg | (DEFAULT_PAUSE_TIME / 2));
+	} else {
+		/* ALL pause frames received are completely ignored */
+		cfg = cgx_read(cgx, lmac_id, CGXX_SMUX_RX_FRM_CTL);
+		cfg &= ~CGX_SMUX_RX_FRM_CTL_CTL_BCK;
+		cgx_write(cgx, lmac_id, CGXX_SMUX_RX_FRM_CTL, cfg);
+
+		cfg = cgx_read(cgx, lmac_id, CGXX_GMP_GMI_RXX_FRM_CTL);
+		cfg &= ~CGX_GMP_GMI_RXX_FRM_CTL_CTL_BCK;
+		cgx_write(cgx, lmac_id, CGXX_GMP_GMI_RXX_FRM_CTL, cfg);
+
+		/* Disable pause frames transmission */
+		cfg = cgx_read(cgx, lmac_id, CGXX_SMUX_TX_CTL);
+		cfg &= ~CGX_SMUX_TX_CTL_L2P_BP_CONV;
+		cgx_write(cgx, lmac_id, CGXX_SMUX_TX_CTL, cfg);
+	}
+}
+
 /* CGX Firmware interface low level support */
 static int cgx_fwi_cmd_send(u64 req, u64 *resp, struct lmac *lmac)
 {
@@ -787,6 +888,7 @@ static int cgx_lmac_init(struct cgx *cgx)
 
 		/* Add reference */
 		cgx->lmac_idmap[i] = lmac;
+		cgx_lmac_pause_frm_config(cgx, i, true);
 	}
 
 	return cgx_lmac_verify_fwi_version(cgx);
@@ -805,6 +907,7 @@ static int cgx_lmac_exit(struct cgx *cgx)
 
 	/* Free all lmac related resources */
 	for (i = 0; i < cgx->lmac_count; i++) {
+		cgx_lmac_pause_frm_config(cgx, i, false);
 		lmac = cgx->lmac_idmap[i];
 		if (!lmac)
 			continue;

drivers/net/ethernet/marvell/octeontx2/af/cgx.h

@@ -60,10 +60,20 @@
 #define CGX_SMUX_RX_FRM_CTL_CTL_BCK	BIT_ULL(3)
 #define CGXX_GMP_GMI_RXX_FRM_CTL	0x38028
 #define CGX_GMP_GMI_RXX_FRM_CTL_CTL_BCK	BIT_ULL(3)
+#define CGXX_SMUX_TX_CTL		0x20178
+#define CGXX_SMUX_TX_PAUSE_PKT_TIME	0x20110
+#define CGXX_SMUX_TX_PAUSE_PKT_INTERVAL	0x20120
+#define CGXX_GMP_GMI_TX_PAUSE_PKT_TIME	0x38230
+#define CGXX_GMP_GMI_TX_PAUSE_PKT_INTERVAL	0x38248
+#define CGX_SMUX_TX_CTL_L2P_BP_CONV	BIT_ULL(7)
+#define CGXX_CMR_RX_OVR_BP		0x130
+#define CGX_CMR_RX_OVR_BP_EN(X)		BIT_ULL(((X) + 8))
+#define CGX_CMR_RX_OVR_BP_BP(X)		BIT_ULL(((X) + 4))
 
 #define CGX_COMMAND_REG			CGXX_SCRATCH1_REG
 #define CGX_EVENT_REG			CGXX_SCRATCH0_REG
 #define CGX_CMD_TIMEOUT			2200 /* msecs */
+#define DEFAULT_PAUSE_TIME		0x7FF
 
 #define CGX_NVEC			37
 #define CGX_LMAC_FWI			0
@@ -124,5 +134,9 @@ int cgx_lmac_internal_loopback(void *cgxd, int lmac_id, bool enable);
 int cgx_get_link_info(void *cgxd, int lmac_id,
 		      struct cgx_link_user_info *linfo);
 int cgx_lmac_linkup_start(void *cgxd);
+int cgx_lmac_get_pause_frm(void *cgxd, int lmac_id,
+			   u8 *tx_pause, u8 *rx_pause);
+int cgx_lmac_set_pause_frm(void *cgxd, int lmac_id,
+			   u8 tx_pause, u8 rx_pause);
 int cgx_get_mkex_prfl_info(u64 *addr, u64 *size);
 #endif /* CGX_H */

drivers/net/ethernet/marvell/octeontx2/af/mbox.h

@@ -143,6 +143,8 @@ M(CGX_STOP_LINKEVENTS,	0x208, cgx_stop_linkevents, msg_req, msg_rsp)	\
 M(CGX_GET_LINKINFO,	0x209, cgx_get_linkinfo, msg_req, cgx_link_info_msg) \
 M(CGX_INTLBK_ENABLE,	0x20A, cgx_intlbk_enable, msg_req, msg_rsp)	\
 M(CGX_INTLBK_DISABLE,	0x20B, cgx_intlbk_disable, msg_req, msg_rsp)	\
+M(CGX_CFG_PAUSE_FRM,	0x20E, cgx_cfg_pause_frm, cgx_pause_frm_cfg,	\
+			       cgx_pause_frm_cfg)			\
 /* NPA mbox IDs (range 0x400 - 0x5FF) */				\
 M(NPA_LF_ALLOC,		0x400, npa_lf_alloc,				\
 				npa_lf_alloc_req, npa_lf_alloc_rsp)	\
@@ -345,6 +347,15 @@ struct cgx_link_info_msg {
 	struct cgx_link_user_info link_info;
 };
 
+struct cgx_pause_frm_cfg {
+	struct mbox_msghdr hdr;
+	u8 set;
+	/* set = 1 if the request is to config pause frames */
+	/* set = 0 if the request is to fetch pause frames config */
+	u8 rx_pause;
+	u8 tx_pause;
+};
+
 /* NPA mbox message formats */
 
 /* NPA mailbox error codes

drivers/net/ethernet/marvell/octeontx2/af/rvu_cgx.c

@@ -590,6 +590,30 @@ int rvu_mbox_handler_cgx_intlbk_disable(struct rvu *rvu, struct msg_req *req,
 	return 0;
 }
 
+int rvu_mbox_handler_cgx_cfg_pause_frm(struct rvu *rvu,
+				       struct cgx_pause_frm_cfg *req,
+				       struct cgx_pause_frm_cfg *rsp)
+{
+	int pf = rvu_get_pf(req->hdr.pcifunc);
+	u8 cgx_id, lmac_id;
+
+	/* This msg is expected only from PF/VFs that are mapped to CGX LMACs,
+	 * if received from other PF/VF simply ACK, nothing to do.
+	 */
+	if (!is_pf_cgxmapped(rvu, pf))
+		return -ENODEV;
+
+	rvu_get_cgx_lmac_id(rvu->pf2cgxlmac_map[pf], &cgx_id, &lmac_id);
+
+	if (req->set)
+		cgx_lmac_set_pause_frm(rvu_cgx_pdata(cgx_id, rvu), lmac_id,
+				       req->tx_pause, req->rx_pause);
+	else
+		cgx_lmac_get_pause_frm(rvu_cgx_pdata(cgx_id, rvu), lmac_id,
+				       &rsp->tx_pause, &rsp->rx_pause);
+	return 0;
+}
+
 /* Finds cumulative status of NIX rx/tx counters from LF of a PF and those
  * from its VFs as well. ie. NIX rx/tx counters at the CGX port level
  */

drivers/net/ethernet/marvell/octeontx2/af/rvu_nix.c

@@ -213,6 +213,11 @@ static int nix_interface_init(struct rvu *rvu, u16 pcifunc, int type, int nixlf)
 		pfvf->tx_chan_cnt = 1;
 		cgx_set_pkind(rvu_cgx_pdata(cgx_id, rvu), lmac_id, pkind);
 		rvu_npc_set_pkind(rvu, pkind, pfvf);
+
+		/* By default we enable pause frames */
+		if ((pcifunc & RVU_PFVF_FUNC_MASK) == 0)
+			cgx_lmac_set_pause_frm(rvu_cgx_pdata(cgx_id, rvu),
+					       lmac_id, true, true);
 		break;
 	case NIX_INTF_TYPE_LBK:
 		vf = (pcifunc & RVU_PFVF_FUNC_MASK) - 1;