[dpdk-dev] [PATCH 5/7] cxgbe: update link Forward Error Correction (FEC)

[Rahul Lakkireddy <rahul.lakkireddy@chelsio.com>]

From: Kumar Sanghvi <kumaras@chelsio.com>

Normally, firmware reads various Forward Error Correction parameters
from a Transceiver Module i2c EPROM and uses a couple of IEEE Standards
(802.3bj for 100Gb/s and 802.3by for 25Gb/s) to interpret those
parameters and come up with supported and default FEC settings.
Firmware then sends these FEC parameters to the Host Driver which gives
the Host Administrator an opportunity to change them if necessary in
order to establish a Link with a Switch which may have made a
non-standard FEC decision.

This commit recognizes "auto" as a discrete FEC mode which can be
used to explicitly select the IEEE 802.3 standard based FEC selection.

Original work by Surendra Mobiya <surendra@chelsio.com>

Signed-off-by: Kumar Sanghvi <kumaras@chelsio.com>
Signed-off-by: Rahul Lakkireddy <rahul.lakkireddy@chelsio.com>
---
 drivers/net/cxgbe/base/common.h |  13 +++--
 drivers/net/cxgbe/base/t4_hw.c  | 123 ++++++++++++++++++++++++++++------------
 2 files changed, 94 insertions(+), 42 deletions(-)

diff --git a/drivers/net/cxgbe/base/common.h b/drivers/net/cxgbe/base/common.h
index dd282a933..0bd78c1b0 100644
--- a/drivers/net/cxgbe/base/common.h
+++ b/drivers/net/cxgbe/base/common.h
@@ -69,9 +69,9 @@ enum {
 };
 
 enum {
-	FEC_RS        = 1 << 0,
-	FEC_BASER_RS  = 1 << 1,
-	FEC_RESERVED  = 1 << 2,
+	FEC_AUTO     = 1 << 0,    /* IEEE 802.3 "automatic" */
+	FEC_RS       = 1 << 1,    /* Reed-Solomon */
+	FEC_BASER_RS = 1 << 2,    /* BaseR/Reed-Solomon */
 };
 
 struct port_stats {
@@ -248,8 +248,11 @@ struct link_config {
 	unsigned int   speed;            /* actual link speed */
 	unsigned char  requested_fc;     /* flow control user has requested */
 	unsigned char  fc;               /* actual link flow control */
-	unsigned char  requested_fec;    /* Forward Error Correction user */
-	unsigned char  fec;              /* has requested and actual FEC */
+	unsigned char  auto_fec;         /* Forward Error Correction (FEC)
+					  * "automatic" (IEEE 802.3)
+					  */
+	unsigned char  requested_fec;    /* FEC requested */
+	unsigned char  fec;              /* FEC actual */
 	unsigned char  autoneg;          /* autonegotiating? */
 	unsigned char  link_ok;          /* link up? */
 };
diff --git a/drivers/net/cxgbe/base/t4_hw.c b/drivers/net/cxgbe/base/t4_hw.c
index 2d7214622..e8545ceb0 100644
--- a/drivers/net/cxgbe/base/t4_hw.c
+++ b/drivers/net/cxgbe/base/t4_hw.c
@@ -2792,6 +2792,58 @@ void t4_dump_version_info(struct adapter *adapter)
 #define ADVERT_MASK (V_FW_PORT_CAP_SPEED(M_FW_PORT_CAP_SPEED) | \
 		     FW_PORT_CAP_ANEG)
 
+/* Translate Firmware Pause specification to Common Code */
+static inline unsigned int fwcap_to_cc_pause(unsigned int fw_pause)
+{
+	unsigned int cc_pause = 0;
+
+	if (fw_pause & F_FW_PORT_CMD_RXPAUSE)
+		cc_pause |= PAUSE_RX;
+	if (fw_pause & F_FW_PORT_CMD_TXPAUSE)
+		cc_pause |= PAUSE_TX;
+
+	return cc_pause;
+}
+
+/* Translate Common Code Pause Frame specification into Firmware */
+static inline unsigned int cc_to_fwcap_pause(unsigned int cc_pause)
+{
+	unsigned int fw_pause = 0;
+
+	if (cc_pause & PAUSE_RX)
+		fw_pause |= F_FW_PORT_CMD_RXPAUSE;
+	if (cc_pause & PAUSE_TX)
+		fw_pause |= F_FW_PORT_CMD_TXPAUSE;
+
+	return fw_pause;
+}
+
+/* Translate Firmware Forward Error Correction specification to Common Code */
+static inline unsigned int fwcap_to_cc_fec(unsigned int fw_fec)
+{
+	unsigned int cc_fec = 0;
+
+	if (fw_fec & FW_PORT_CAP_FEC_RS)
+		cc_fec |= FEC_RS;
+	if (fw_fec & FW_PORT_CAP_FEC_BASER_RS)
+		cc_fec |= FEC_BASER_RS;
+
+	return cc_fec;
+}
+
+/* Translate Common Code Forward Error Correction specification to Firmware */
+static inline unsigned int cc_to_fwcap_fec(unsigned int cc_fec)
+{
+	unsigned int fw_fec = 0;
+
+	if (cc_fec & FEC_RS)
+		fw_fec |= FW_PORT_CAP_FEC_RS;
+	if (cc_fec & FEC_BASER_RS)
+		fw_fec |= FW_PORT_CAP_FEC_BASER_RS;
+
+	return fw_fec;
+}
+
 /**
  * t4_link_l1cfg - apply link configuration to MAC/PHY
  * @phy: the PHY to setup
@@ -2809,23 +2861,25 @@ int t4_link_l1cfg(struct adapter *adap, unsigned int mbox, unsigned int port,
 		  struct link_config *lc)
 {
 	struct fw_port_cmd c;
-	unsigned int mdi = V_FW_PORT_CAP_MDI(FW_PORT_CAP_MDI_AUTO);
-	unsigned int fc, fec;
+	unsigned int fw_mdi = V_FW_PORT_CAP_MDI(FW_PORT_CAP_MDI_AUTO);
+	unsigned int fw_fc, cc_fec, fw_fec;
 
 	lc->link_ok = 0;
-	fc = 0;
-	if (lc->requested_fc & PAUSE_RX)
-		fc |= FW_PORT_CAP_FC_RX;
-	if (lc->requested_fc & PAUSE_TX)
-		fc |= FW_PORT_CAP_FC_TX;
-
-	fec = 0;
-	if (lc->requested_fec & FEC_RS)
-		fec |= FW_PORT_CAP_FEC_RS;
-	if (lc->requested_fec & FEC_BASER_RS)
-		fec |= FW_PORT_CAP_FEC_BASER_RS;
-	if (lc->requested_fec & FEC_RESERVED)
-		fec |= FW_PORT_CAP_FEC_RESERVED;
+
+	fw_fc = cc_to_fwcap_pause(lc->requested_fc);
+
+	/* Convert Common Code Forward Error Control settings into the
+	 * Firmware's API.  If the current Requested FEC has "Automatic"
+	 * (IEEE 802.3) specified, then we use whatever the Firmware
+	 * sent us as part of it's IEEE 802.3-based interpratation of
+	 * the Transceiver Module EPROM FEC parameters.  Otherwise we
+	 * use whatever is in the current Requested FEC settings.
+	 */
+	if (lc->requested_fec & FEC_AUTO)
+		cc_fec = lc->auto_fec;
+	else
+		cc_fec = lc->requested_fec;
+	fw_fec = cc_to_fwcap_fec(cc_fec);
 
 	memset(&c, 0, sizeof(c));
 	c.op_to_portid = cpu_to_be32(V_FW_CMD_OP(FW_PORT_CMD) |
@@ -2837,16 +2891,17 @@ int t4_link_l1cfg(struct adapter *adap, unsigned int mbox, unsigned int port,
 
 	if (!(lc->supported & FW_PORT_CAP_ANEG)) {
 		c.u.l1cfg.rcap = cpu_to_be32((lc->supported & ADVERT_MASK) |
-					     fc | fec);
+					     fw_fc | fw_fec);
 		lc->fc = lc->requested_fc & ~PAUSE_AUTONEG;
-		lc->fec = lc->requested_fec;
+		lc->fec = cc_fec;
 	} else if (lc->autoneg == AUTONEG_DISABLE) {
-		c.u.l1cfg.rcap = cpu_to_be32(lc->requested_speed | fc |
-					     fec | mdi);
+		c.u.l1cfg.rcap = cpu_to_be32(lc->requested_speed | fw_fc |
+					     fw_fec | fw_mdi);
 		lc->fc = lc->requested_fc & ~PAUSE_AUTONEG;
-		lc->fec = lc->requested_fec;
+		lc->fec = cc_fec;
 	} else {
-		c.u.l1cfg.rcap = cpu_to_be32(lc->advertising | fc | fec | mdi);
+		c.u.l1cfg.rcap = cpu_to_be32(lc->advertising | fw_fc | fw_fec |
+					     fw_mdi);
 	}
 
 	return t4_wr_mbox(adap, mbox, &c, sizeof(c), NULL);
@@ -4212,11 +4267,11 @@ int t4_handle_fw_rpl(struct adapter *adap, const __be64 *rpl)
 		u32 stat = be32_to_cpu(p->u.info.lstatus_to_modtype);
 		int link_ok = (stat & F_FW_PORT_CMD_LSTATUS) != 0;
 		u32 mod = G_FW_PORT_CMD_MODTYPE(stat);
+		unsigned int fec;
+
+		fc = fwcap_to_cc_pause(stat);
+		fec = fwcap_to_cc_fec(stat);
 
-		if (stat & F_FW_PORT_CMD_RXPAUSE)
-			fc |= PAUSE_RX;
-		if (stat & F_FW_PORT_CMD_TXPAUSE)
-			fc |= PAUSE_TX;
 		if (stat & V_FW_PORT_CMD_LSPEED(FW_PORT_CAP_SPEED_100M))
 			speed = ETH_SPEED_NUM_100M;
 		else if (stat & V_FW_PORT_CMD_LSPEED(FW_PORT_CAP_SPEED_1G))
@@ -4238,11 +4293,12 @@ int t4_handle_fw_rpl(struct adapter *adap, const __be64 *rpl)
 		lc = &pi->link_cfg;
 
 		if (mod != pi->mod_type) {
+			lc->auto_fec = fec;
 			pi->mod_type = mod;
 			t4_os_portmod_changed(adap, i);
 		}
 		if (link_ok != lc->link_ok || speed != lc->speed ||
-		    fc != lc->fc) {                    /* something changed */
+		    fc != lc->fc || fec != lc->fec) { /* something changed */
 			if (!link_ok && lc->link_ok) {
 				static const char * const reason[] = {
 					"Link Down",
@@ -4262,6 +4318,7 @@ int t4_handle_fw_rpl(struct adapter *adap, const __be64 *rpl)
 			lc->link_ok = link_ok;
 			lc->speed = speed;
 			lc->fc = fc;
+			lc->fec = fec;
 			lc->supported = be16_to_cpu(p->u.info.pcap);
 		}
 	} else {
@@ -4295,8 +4352,6 @@ void t4_reset_link_config(struct adapter *adap, int idx)
 static void init_link_config(struct link_config *lc, unsigned int pcaps,
 			     unsigned int acaps)
 {
-	unsigned int fec;
-
 	lc->supported = pcaps;
 	lc->requested_speed = 0;
 	lc->speed = 0;
@@ -4307,15 +4362,9 @@ static void init_link_config(struct link_config *lc, unsigned int pcaps,
 	 * For Forward Error Control, we default to whatever the Firmware
 	 * tells us the Link is currently advertising.
 	 */
-	fec = 0;
-	if (acaps & FW_PORT_CAP_FEC_RS)
-		fec |= FEC_RS;
-	if (acaps & FW_PORT_CAP_FEC_BASER_RS)
-		fec |= FEC_BASER_RS;
-	if (acaps & FW_PORT_CAP_FEC_RESERVED)
-		fec |= FEC_RESERVED;
-	lc->requested_fec = fec;
-	lc->fec = fec;
+	lc->auto_fec = fwcap_to_cc_fec(acaps);
+	lc->requested_fec = FEC_AUTO;
+	lc->fec = lc->auto_fec;
 
 	if (lc->supported & FW_PORT_CAP_ANEG) {
 		lc->advertising = lc->supported & ADVERT_MASK;
-- 
2.15.1