cxgb3 - Fix potential MAC hang

Under rare conditions, the MAC might hang while generating a pause frame.
This patch fine tunes the MAC settings to avoid the issue, allows for
periodic MAC state check, and triggers a recovery if hung.

Also fix one MAC statistics counter for the rev board T3B2.

Signed-off-by: Divy Le Ray <divy@chelsio.com>
Signed-off-by: Jeff Garzik <jeff@garzik.org>

1 files changed, 118 insertions, 15 deletions

diff --git a/drivers/net/cxgb3/xgmac.c b/drivers/net/cxgb3/xgmac.c
index 907a272ae32..2b42c13ba8e 100644
--- a/drivers/net/cxgb3/xgmac.c
+++ b/drivers/net/cxgb3/xgmac.c
@@ -124,9 +124,6 @@ int t3_mac_reset(struct cmac *mac)
                         xaui_serdes_reset(mac);
         }
 
-        if (adap->params.rev > 0)
-                t3_write_reg(adap, A_XGM_PAUSE_TIMER + oft, 0xf000);
-
         val = F_MAC_RESET_;
         if (is_10G(adap))
                 val |= F_PCS_RESET_;
@@ -145,6 +142,58 @@ int t3_mac_reset(struct cmac *mac)
         return 0;
 }
 
+int t3b2_mac_reset(struct cmac *mac)
+{
+        struct adapter *adap = mac->adapter;
+        unsigned int oft = mac->offset;
+        u32 val;
+
+        if (!macidx(mac)) 
+                t3_set_reg_field(adap, A_MPS_CFG, F_PORT0ACTIVE, 0);
+        else
+                t3_set_reg_field(adap, A_MPS_CFG, F_PORT1ACTIVE, 0);
+
+        t3_write_reg(adap, A_XGM_RESET_CTRL + oft, F_MAC_RESET_);
+        t3_read_reg(adap, A_XGM_RESET_CTRL + oft);    /* flush */
+
+        msleep(10);
+
+        /* Check for xgm Rx fifo empty */
+        if (t3_wait_op_done(adap, A_XGM_RX_MAX_PKT_SIZE_ERR_CNT + oft,
+                            0x80000000, 1, 5, 2)) {
+                CH_ERR(adap, "MAC %d Rx fifo drain failed\n",
+                       macidx(mac));
+                return -1;
+        }
+
+        t3_write_reg(adap, A_XGM_RESET_CTRL + oft, 0);
+        t3_read_reg(adap, A_XGM_RESET_CTRL + oft);    /* flush */
+
+        val = F_MAC_RESET_;
+        if (is_10G(adap))
+                val |= F_PCS_RESET_;
+        else if (uses_xaui(adap))
+                val |= F_PCS_RESET_ | F_XG2G_RESET_;
+        else
+                val |= F_RGMII_RESET_ | F_XG2G_RESET_;
+        t3_write_reg(adap, A_XGM_RESET_CTRL + oft, val);
+        t3_read_reg(adap, A_XGM_RESET_CTRL + oft);  /* flush */
+        if ((val & F_PCS_RESET_) && adap->params.rev) {
+                msleep(1);
+                t3b_pcs_reset(mac);
+        }
+        t3_write_reg(adap, A_XGM_RX_CFG + oft, 
+                     F_DISPAUSEFRAMES | F_EN1536BFRAMES |
+                     F_RMFCS | F_ENJUMBO | F_ENHASHMCAST);
+
+        if (!macidx(mac)) 
+                t3_set_reg_field(adap, A_MPS_CFG, 0, F_PORT0ACTIVE);
+        else
+                t3_set_reg_field(adap, A_MPS_CFG, 0, F_PORT1ACTIVE);
+
+        return 0;
+}
+
 /*
  * Set the exact match register 'idx' to recognize the given Ethernet address.
  */
@@ -251,9 +300,11 @@ int t3_mac_set_mtu(struct cmac *mac, unsigned int mtu)
          * Adjust the PAUSE frame watermarks.  We always set the LWM, and the
          * HWM only if flow-control is enabled.
          */
-        hwm = max(MAC_RXFIFO_SIZE - 3 * mtu, MAC_RXFIFO_SIZE / 2U);
-        hwm = min(hwm, 3 * MAC_RXFIFO_SIZE / 4 + 1024);
-        lwm = hwm - 1024;
+        hwm = max_t(unsigned int, MAC_RXFIFO_SIZE - 3 * mtu, 
+                    MAC_RXFIFO_SIZE * 38 / 100);
+        hwm = min(hwm, MAC_RXFIFO_SIZE - 8192);
+        lwm = min(3 * (int)mtu, MAC_RXFIFO_SIZE / 4);
+
         v = t3_read_reg(adap, A_XGM_RXFIFO_CFG + mac->offset);
         v &= ~V_RXFIFOPAUSELWM(M_RXFIFOPAUSELWM);
         v |= V_RXFIFOPAUSELWM(lwm / 8);
@@ -270,7 +321,15 @@ int t3_mac_set_mtu(struct cmac *mac, unsigned int mtu)
         thres = mtu > thres ? (mtu - thres + 7) / 8 : 0;
         thres = max(thres, 8U); /* need at least 8 */
         t3_set_reg_field(adap, A_XGM_TXFIFO_CFG + mac->offset,
-                         V_TXFIFOTHRESH(M_TXFIFOTHRESH), V_TXFIFOTHRESH(thres));
+                         V_TXFIFOTHRESH(M_TXFIFOTHRESH) | V_TXIPG(M_TXIPG),
+                         V_TXFIFOTHRESH(thres) | V_TXIPG(1));
+
+        if (adap->params.rev > 0)
+                t3_write_reg(adap, A_XGM_PAUSE_TIMER + mac->offset,
+                             (hwm - lwm) * 4 / 8);
+        t3_write_reg(adap, A_XGM_TX_PAUSE_QUANTA + mac->offset,
+                     MAC_RXFIFO_SIZE * 4 * 8 / 512);
+
         return 0;
 }
 
@@ -298,12 +357,6 @@ int t3_mac_set_speed_duplex_fc(struct cmac *mac, int speed, int duplex, int fc)
                                  V_PORTSPEED(M_PORTSPEED), val);
         }
 
-        val = t3_read_reg(adap, A_XGM_RXFIFO_CFG + oft);
-        val &= ~V_RXFIFOPAUSEHWM(M_RXFIFOPAUSEHWM);
-        if (fc & PAUSE_TX)
-                val |= V_RXFIFOPAUSEHWM(G_RXFIFOPAUSELWM(val) + 128);   /* +1KB */
-        t3_write_reg(adap, A_XGM_RXFIFO_CFG + oft, val);
-
         t3_set_reg_field(adap, A_XGM_TX_CFG + oft, F_TXPAUSEEN,
                          (fc & PAUSE_RX) ? F_TXPAUSEEN : 0);
         return 0;
@@ -318,9 +371,17 @@ int t3_mac_enable(struct cmac *mac, int which)
         if (which & MAC_DIRECTION_TX) {
                 t3_write_reg(adap, A_XGM_TX_CTRL + oft, F_TXEN);
                 t3_write_reg(adap, A_TP_PIO_ADDR, A_TP_TX_DROP_CFG_CH0 + idx);
-                t3_write_reg(adap, A_TP_PIO_DATA, 0xbf000001);
+                t3_write_reg(adap, A_TP_PIO_DATA, 0xc0ede401);
                 t3_write_reg(adap, A_TP_PIO_ADDR, A_TP_TX_DROP_MODE);
                 t3_set_reg_field(adap, A_TP_PIO_DATA, 1 << idx, 1 << idx);
+
+                t3_write_reg(adap, A_TP_PIO_ADDR, A_TP_TX_DROP_CNT_CH0 + idx);
+                mac->tcnt = (G_TXDROPCNTCH0RCVD(t3_read_reg(adap,
+                                                            A_TP_PIO_DATA)));
+                mac->xcnt = (G_TXSPI4SOPCNT(t3_read_reg(adap,
+                                                A_XGM_TX_SPI4_SOP_EOP_CNT)));
+                mac->txen = F_TXEN;
+                mac->toggle_cnt = 0;
         }
         if (which & MAC_DIRECTION_RX)
                 t3_write_reg(adap, A_XGM_RX_CTRL + oft, F_RXEN);
@@ -337,13 +398,50 @@ int t3_mac_disable(struct cmac *mac, int which)
                 t3_write_reg(adap, A_TP_PIO_ADDR, A_TP_TX_DROP_CFG_CH0 + idx);
                 t3_write_reg(adap, A_TP_PIO_DATA, 0xc000001f);
                 t3_write_reg(adap, A_TP_PIO_ADDR, A_TP_TX_DROP_MODE);
-                t3_set_reg_field(adap, A_TP_PIO_DATA, 1 << idx, 0);
+                t3_set_reg_field(adap, A_TP_PIO_DATA, 1 << idx, 1 << idx);
+                mac->txen = 0;
         }
         if (which & MAC_DIRECTION_RX)
                 t3_write_reg(adap, A_XGM_RX_CTRL + mac->offset, 0);
         return 0;
 }
 
+int t3b2_mac_watchdog_task(struct cmac *mac)
+{
+        struct adapter *adap = mac->adapter;
+        unsigned int tcnt, xcnt;
+        int status;
+
+        t3_write_reg(adap, A_TP_PIO_ADDR, A_TP_TX_DROP_CNT_CH0 + macidx(mac));
+        tcnt = (G_TXDROPCNTCH0RCVD(t3_read_reg(adap, A_TP_PIO_DATA)));
+        xcnt = (G_TXSPI4SOPCNT(t3_read_reg(adap, 
+                                           A_XGM_TX_SPI4_SOP_EOP_CNT +
+                                           mac->offset)));
+
+        if (tcnt != mac->tcnt && xcnt == 0 && mac->xcnt == 0) {
+                if (mac->toggle_cnt > 4) {
+                        t3b2_mac_reset(mac);
+                        mac->toggle_cnt = 0;
+                        status = 2;
+                } else {
+                        t3_write_reg(adap, A_XGM_TX_CTRL + mac->offset, 0);
+                        t3_read_reg(adap, A_XGM_TX_CTRL + mac->offset);
+                        t3_write_reg(adap, A_XGM_TX_CTRL + mac->offset,
+                                     mac->txen);
+                        t3_read_reg(adap, A_XGM_TX_CTRL + mac->offset);
+                        mac->toggle_cnt++;
+                        status = 1;
+                }       
+        } else {
+                mac->toggle_cnt = 0;
+                status = 0;
+        }
+        mac->tcnt = tcnt;
+        mac->xcnt = xcnt;
+
+        return status;
+}
+
 /*
  * This function is called periodically to accumulate the current values of the
  * RMON counters into the port statistics.  Since the packet counters are only
@@ -375,6 +473,11 @@ const struct mac_stats *t3_mac_update_stats(struct cmac *mac)
         RMON_UPDATE(mac, rx_too_long, RX_OVERSIZE_FRAMES);
         mac->stats.rx_too_long += RMON_READ(mac, A_XGM_RX_MAX_PKT_SIZE_ERR_CNT);
 
+        v = RMON_READ(mac, A_XGM_RX_MAX_PKT_SIZE_ERR_CNT);
+        if (mac->adapter->params.rev == T3_REV_B2)
+                v &= 0x7fffffff;
+        mac->stats.rx_too_long += v;
+
         RMON_UPDATE(mac, rx_frames_64, RX_64B_FRAMES);
         RMON_UPDATE(mac, rx_frames_65_127, RX_65_127B_FRAMES);
         RMON_UPDATE(mac, rx_frames_128_255, RX_128_255B_FRAMES);