ixgbe: Fix backplane flow control autoneg

Backplane flow control autonegotiation is currently broken for
ixgbe devices.  This patch fixes the flow control issues
with clause 37 autoneg.

Signed-off-by: Peter P Waskiewicz Jr <peter.p.waskiewicz.jr@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

3 files changed, 187 insertions, 52 deletions

diff --git a/drivers/net/ixgbe/ixgbe_82598.c b/drivers/net/ixgbe/ixgbe_82598.c
index 56b12f3192f..e2d5343f127 100644
--- a/drivers/net/ixgbe/ixgbe_82598.c
+++ b/drivers/net/ixgbe/ixgbe_82598.c
@@ -425,7 +425,7 @@ static s32 ixgbe_fc_enable_82598(struct ixgbe_hw *hw, s32 packetbuf_num)
 #endif /* CONFIG_DCB */
         default:
                 hw_dbg(hw, "Flow control param set incorrectly\n");
-                ret_val = -IXGBE_ERR_CONFIG;
+                ret_val = IXGBE_ERR_CONFIG;
                 goto out;
                 break;
         }
diff --git a/drivers/net/ixgbe/ixgbe_common.c b/drivers/net/ixgbe/ixgbe_common.c
index 6621e172df3..143b0fcbe95 100644
--- a/drivers/net/ixgbe/ixgbe_common.c
+++ b/drivers/net/ixgbe/ixgbe_common.c
@@ -1663,7 +1663,7 @@ s32 ixgbe_fc_enable_generic(struct ixgbe_hw *hw, s32 packetbuf_num)
 #endif /* CONFIG_DCB */
         default:
                 hw_dbg(hw, "Flow control param set incorrectly\n");
-                ret_val = -IXGBE_ERR_CONFIG;
+                ret_val = IXGBE_ERR_CONFIG;
                 goto out;
                 break;
         }
@@ -1734,75 +1734,140 @@ s32 ixgbe_fc_autoneg(struct ixgbe_hw *hw)
         s32 ret_val = 0;
         ixgbe_link_speed speed;
         u32 pcs_anadv_reg, pcs_lpab_reg, linkstat;
+        u32 links2, anlp1_reg, autoc_reg, links;
         bool link_up;
 
         /*
          * AN should have completed when the cable was plugged in.
          * Look for reasons to bail out.  Bail out if:
          * - FC autoneg is disabled, or if
-         * - we don't have multispeed fiber, or if
-         * - we're not running at 1G, or if
-         * - link is not up, or if
-         * - link is up but AN did not complete, or if
-         * - link is up and AN completed but timed out
+         * - link is not up.
          *
-         * Since we're being called from an LSC, link is already know to be up.
+         * Since we're being called from an LSC, link is already known to be up.
          * So use link_up_wait_to_complete=false.
          */
         hw->mac.ops.check_link(hw, &speed, &link_up, false);
-        linkstat = IXGBE_READ_REG(hw, IXGBE_PCS1GLSTA);
-
-        if (hw->fc.disable_fc_autoneg ||
-            !hw->phy.multispeed_fiber ||
-            (speed != IXGBE_LINK_SPEED_1GB_FULL) ||
-            !link_up ||
-            ((linkstat & IXGBE_PCS1GLSTA_AN_COMPLETE) == 0) ||
-            ((linkstat & IXGBE_PCS1GLSTA_AN_TIMED_OUT) == 1)) {
+
+        if (hw->fc.disable_fc_autoneg || (!link_up)) {
                 hw->fc.fc_was_autonegged = false;
                 hw->fc.current_mode = hw->fc.requested_mode;
-                hw_dbg(hw, "Autoneg FC was skipped.\n");
                 goto out;
         }
 
         /*
+         * On backplane, bail out if
+         * - backplane autoneg was not completed, or if
+         * - link partner is not AN enabled
+         */
+        if (hw->phy.media_type == ixgbe_media_type_backplane) {
+                links = IXGBE_READ_REG(hw, IXGBE_LINKS);
+                links2 = IXGBE_READ_REG(hw, IXGBE_LINKS2);
+                if (((links & IXGBE_LINKS_KX_AN_COMP) == 0) ||
+                    ((links2 & IXGBE_LINKS2_AN_SUPPORTED) == 0)) {
+                        hw->fc.fc_was_autonegged = false;
+                        hw->fc.current_mode = hw->fc.requested_mode;
+                        goto out;
+                }
+        }
+
+        /*
+         * On multispeed fiber at 1g, bail out if
+         * - link is up but AN did not complete, or if
+         * - link is up and AN completed but timed out
+         */
+        if (hw->phy.multispeed_fiber && (speed == IXGBE_LINK_SPEED_1GB_FULL)) {
+                linkstat = IXGBE_READ_REG(hw, IXGBE_PCS1GLSTA);
+                if (((linkstat & IXGBE_PCS1GLSTA_AN_COMPLETE) == 0) ||
+                    ((linkstat & IXGBE_PCS1GLSTA_AN_TIMED_OUT) == 1)) {
+                        hw->fc.fc_was_autonegged = false;
+                        hw->fc.current_mode = hw->fc.requested_mode;
+                        goto out;
+                }
+        }
+
+        /*
          * Read the AN advertisement and LP ability registers and resolve
          * local flow control settings accordingly
          */
-        pcs_anadv_reg = IXGBE_READ_REG(hw, IXGBE_PCS1GANA);
-        pcs_lpab_reg = IXGBE_READ_REG(hw, IXGBE_PCS1GANLP);
-        if ((pcs_anadv_reg & IXGBE_PCS1GANA_SYM_PAUSE) &&
-                (pcs_lpab_reg & IXGBE_PCS1GANA_SYM_PAUSE)) {
+        if ((speed == IXGBE_LINK_SPEED_1GB_FULL) &&
+            (hw->phy.media_type != ixgbe_media_type_backplane)) {
+                pcs_anadv_reg = IXGBE_READ_REG(hw, IXGBE_PCS1GANA);
+                pcs_lpab_reg = IXGBE_READ_REG(hw, IXGBE_PCS1GANLP);
+                if ((pcs_anadv_reg & IXGBE_PCS1GANA_SYM_PAUSE) &&
+                    (pcs_lpab_reg & IXGBE_PCS1GANA_SYM_PAUSE)) {
+                        /*
+                         * Now we need to check if the user selected Rx ONLY
+                         * of pause frames.  In this case, we had to advertise
+                         * FULL flow control because we could not advertise RX
+                         * ONLY. Hence, we must now check to see if we need to
+                         * turn OFF the TRANSMISSION of PAUSE frames.
+                         */
+                        if (hw->fc.requested_mode == ixgbe_fc_full) {
+                                hw->fc.current_mode = ixgbe_fc_full;
+                                hw_dbg(hw, "Flow Control = FULL.\n");
+                        } else {
+                                hw->fc.current_mode = ixgbe_fc_rx_pause;
+                                hw_dbg(hw, "Flow Control=RX PAUSE only\n");
+                        }
+                } else if (!(pcs_anadv_reg & IXGBE_PCS1GANA_SYM_PAUSE) &&
+                           (pcs_anadv_reg & IXGBE_PCS1GANA_ASM_PAUSE) &&
+                           (pcs_lpab_reg & IXGBE_PCS1GANA_SYM_PAUSE) &&
+                           (pcs_lpab_reg & IXGBE_PCS1GANA_ASM_PAUSE)) {
+                        hw->fc.current_mode = ixgbe_fc_tx_pause;
+                        hw_dbg(hw, "Flow Control = TX PAUSE frames only.\n");
+                } else if ((pcs_anadv_reg & IXGBE_PCS1GANA_SYM_PAUSE) &&
+                           (pcs_anadv_reg & IXGBE_PCS1GANA_ASM_PAUSE) &&
+                           !(pcs_lpab_reg & IXGBE_PCS1GANA_SYM_PAUSE) &&
+                           (pcs_lpab_reg & IXGBE_PCS1GANA_ASM_PAUSE)) {
+                        hw->fc.current_mode = ixgbe_fc_rx_pause;
+                        hw_dbg(hw, "Flow Control = RX PAUSE frames only.\n");
+                } else {
+                        hw->fc.current_mode = ixgbe_fc_none;
+                        hw_dbg(hw, "Flow Control = NONE.\n");
+                }
+        }
+
+        if (hw->phy.media_type == ixgbe_media_type_backplane) {
                 /*
-                 * Now we need to check if the user selected Rx ONLY
-                 * of pause frames.  In this case, we had to advertise
-                 * FULL flow control because we could not advertise RX
-                 * ONLY. Hence, we must now check to see if we need to
-                 * turn OFF the TRANSMISSION of PAUSE frames.
+                 * Read the 10g AN autoc and LP ability registers and resolve
+                 * local flow control settings accordingly
                  */
-                if (hw->fc.requested_mode == ixgbe_fc_full) {
-                        hw->fc.current_mode = ixgbe_fc_full;
-                        hw_dbg(hw, "Flow Control = FULL.\n");
-                } else {
+                autoc_reg = IXGBE_READ_REG(hw, IXGBE_AUTOC);
+                anlp1_reg = IXGBE_READ_REG(hw, IXGBE_ANLP1);
+
+                if ((autoc_reg & IXGBE_AUTOC_SYM_PAUSE) &&
+                    (anlp1_reg & IXGBE_ANLP1_SYM_PAUSE)) {
+                        /*
+                         * Now we need to check if the user selected Rx ONLY
+                         * of pause frames.  In this case, we had to advertise
+                         * FULL flow control because we could not advertise RX
+                         * ONLY. Hence, we must now check to see if we need to
+                         * turn OFF the TRANSMISSION of PAUSE frames.
+                         */
+                        if (hw->fc.requested_mode == ixgbe_fc_full) {
+                                hw->fc.current_mode = ixgbe_fc_full;
+                                hw_dbg(hw, "Flow Control = FULL.\n");
+                        } else {
+                                hw->fc.current_mode = ixgbe_fc_rx_pause;
+                                hw_dbg(hw, "Flow Control=RX PAUSE only\n");
+                        }
+                } else if (!(autoc_reg & IXGBE_AUTOC_SYM_PAUSE) &&
+                           (autoc_reg & IXGBE_AUTOC_ASM_PAUSE) &&
+                           (anlp1_reg & IXGBE_ANLP1_SYM_PAUSE) &&
+                           (anlp1_reg & IXGBE_ANLP1_ASM_PAUSE)) {
+                        hw->fc.current_mode = ixgbe_fc_tx_pause;
+                        hw_dbg(hw, "Flow Control = TX PAUSE frames only.\n");
+                } else if ((autoc_reg & IXGBE_AUTOC_SYM_PAUSE) &&
+                           (autoc_reg & IXGBE_AUTOC_ASM_PAUSE) &&
+                           !(anlp1_reg & IXGBE_ANLP1_SYM_PAUSE) &&
+                           (anlp1_reg & IXGBE_ANLP1_ASM_PAUSE)) {
                         hw->fc.current_mode = ixgbe_fc_rx_pause;
                         hw_dbg(hw, "Flow Control = RX PAUSE frames only.\n");
+                } else {
+                        hw->fc.current_mode = ixgbe_fc_none;
+                        hw_dbg(hw, "Flow Control = NONE.\n");
                 }
-        } else if (!(pcs_anadv_reg & IXGBE_PCS1GANA_SYM_PAUSE) &&
-                   (pcs_anadv_reg & IXGBE_PCS1GANA_ASM_PAUSE) &&
-                   (pcs_lpab_reg & IXGBE_PCS1GANA_SYM_PAUSE) &&
-                   (pcs_lpab_reg & IXGBE_PCS1GANA_ASM_PAUSE)) {
-                hw->fc.current_mode = ixgbe_fc_tx_pause;
-                hw_dbg(hw, "Flow Control = TX PAUSE frames only.\n");
-        } else if ((pcs_anadv_reg & IXGBE_PCS1GANA_SYM_PAUSE) &&
-                   (pcs_anadv_reg & IXGBE_PCS1GANA_ASM_PAUSE) &&
-                   !(pcs_lpab_reg & IXGBE_PCS1GANA_SYM_PAUSE) &&
-                   (pcs_lpab_reg & IXGBE_PCS1GANA_ASM_PAUSE)) {
-                hw->fc.current_mode = ixgbe_fc_rx_pause;
-                hw_dbg(hw, "Flow Control = RX PAUSE frames only.\n");
-        } else {
-                hw->fc.current_mode = ixgbe_fc_none;
-                hw_dbg(hw, "Flow Control = NONE.\n");
         }
-
         /* Record that current_mode is the result of a successful autoneg */
         hw->fc.fc_was_autonegged = true;
 
@@ -1919,7 +1984,7 @@ static s32 ixgbe_setup_fc(struct ixgbe_hw *hw, s32 packetbuf_num)
 #endif /* CONFIG_DCB */
         default:
                 hw_dbg(hw, "Flow control param set incorrectly\n");
-                ret_val = -IXGBE_ERR_CONFIG;
+                ret_val = IXGBE_ERR_CONFIG;
                 goto out;
                 break;
         }
@@ -1927,9 +1992,6 @@ static s32 ixgbe_setup_fc(struct ixgbe_hw *hw, s32 packetbuf_num)
         IXGBE_WRITE_REG(hw, IXGBE_PCS1GANA, reg);
         reg = IXGBE_READ_REG(hw, IXGBE_PCS1GLCTL);
 
-        /* Enable and restart autoneg to inform the link partner */
-        reg |= IXGBE_PCS1GLCTL_AN_ENABLE | IXGBE_PCS1GLCTL_AN_RESTART;
-
         /* Disable AN timeout */
         if (hw->fc.strict_ieee)
                 reg &= ~IXGBE_PCS1GLCTL_AN_1G_TIMEOUT_EN;
@@ -1937,6 +1999,70 @@ static s32 ixgbe_setup_fc(struct ixgbe_hw *hw, s32 packetbuf_num)
         IXGBE_WRITE_REG(hw, IXGBE_PCS1GLCTL, reg);
         hw_dbg(hw, "Set up FC; PCS1GLCTL = 0x%08X\n", reg);
 
+        /*
+         * Set up the 10G flow control advertisement registers so the HW
+         * can do fc autoneg once the cable is plugged in.  If we end up
+         * using 1g instead, this is harmless.
+         */
+        reg = IXGBE_READ_REG(hw, IXGBE_AUTOC);
+
+        /*
+         * The possible values of fc.requested_mode are:
+         * 0: Flow control is completely disabled
+         * 1: Rx flow control is enabled (we can receive pause frames,
+         *    but not send pause frames).
+         * 2: Tx flow control is enabled (we can send pause frames but
+         *    we do not support receiving pause frames).
+         * 3: Both Rx and Tx flow control (symmetric) are enabled.
+         * other: Invalid.
+         */
+        switch (hw->fc.requested_mode) {
+        case ixgbe_fc_none:
+                /* Flow control completely disabled by software override. */
+                reg &= ~(IXGBE_AUTOC_SYM_PAUSE | IXGBE_AUTOC_ASM_PAUSE);
+                break;
+        case ixgbe_fc_rx_pause:
+                /*
+                 * Rx Flow control is enabled and Tx Flow control is
+                 * disabled by software override. Since there really
+                 * isn't a way to advertise that we are capable of RX
+                 * Pause ONLY, we will advertise that we support both
+                 * symmetric and asymmetric Rx PAUSE.  Later, we will
+                 * disable the adapter's ability to send PAUSE frames.
+                 */
+                reg |= (IXGBE_AUTOC_SYM_PAUSE | IXGBE_AUTOC_ASM_PAUSE);
+                break;
+        case ixgbe_fc_tx_pause:
+                /*
+                 * Tx Flow control is enabled, and Rx Flow control is
+                 * disabled by software override.
+                 */
+                reg |= (IXGBE_AUTOC_ASM_PAUSE);
+                reg &= ~(IXGBE_AUTOC_SYM_PAUSE);
+                break;
+        case ixgbe_fc_full:
+                /* Flow control (both Rx and Tx) is enabled by SW override. */
+                reg |= (IXGBE_AUTOC_SYM_PAUSE | IXGBE_AUTOC_ASM_PAUSE);
+                break;
+#ifdef CONFIG_DCB
+        case ixgbe_fc_pfc:
+                goto out;
+                break;
+#endif /* CONFIG_DCB */
+        default:
+                hw_dbg(hw, "Flow control param set incorrectly\n");
+                ret_val = IXGBE_ERR_CONFIG;
+                goto out;
+                break;
+        }
+        /*
+         * AUTOC restart handles negotiation of 1G and 10G. There is
+         * no need to set the PCS1GCTL register.
+         */
+        reg |= IXGBE_AUTOC_AN_RESTART;
+        IXGBE_WRITE_REG(hw, IXGBE_AUTOC, reg);
+        hw_dbg(hw, "Set up FC; IXGBE_AUTOC = 0x%08X\n", reg);
+
 out:
         return ret_val;
 }
@@ -2000,7 +2126,7 @@ s32 ixgbe_acquire_swfw_sync(struct ixgbe_hw *hw, u16 mask)
 
         while (timeout) {
                 if (ixgbe_get_eeprom_semaphore(hw))
-                        return -IXGBE_ERR_SWFW_SYNC;
+                        return IXGBE_ERR_SWFW_SYNC;
 
                 gssr = IXGBE_READ_REG(hw, IXGBE_GSSR);
                 if (!(gssr & (fwmask | swmask)))
@@ -2017,7 +2143,7 @@ s32 ixgbe_acquire_swfw_sync(struct ixgbe_hw *hw, u16 mask)
 
         if (!timeout) {
                 hw_dbg(hw, "Driver can't access resource, GSSR timeout.\n");
-                return -IXGBE_ERR_SWFW_SYNC;
+                return IXGBE_ERR_SWFW_SYNC;
         }
 
         gssr |= swmask;
diff --git a/drivers/net/ixgbe/ixgbe_type.h b/drivers/net/ixgbe/ixgbe_type.h
index 8761d7899f7..7c93e923bf2 100644
--- a/drivers/net/ixgbe/ixgbe_type.h
+++ b/drivers/net/ixgbe/ixgbe_type.h
@@ -1336,6 +1336,8 @@
 #define IXGBE_AUTOC_KX4_SUPP    0x80000000
 #define IXGBE_AUTOC_KX_SUPP     0x40000000
 #define IXGBE_AUTOC_PAUSE       0x30000000
+#define IXGBE_AUTOC_ASM_PAUSE   0x20000000
+#define IXGBE_AUTOC_SYM_PAUSE   0x10000000
 #define IXGBE_AUTOC_RF          0x08000000
 #define IXGBE_AUTOC_PD_TMR      0x06000000
 #define IXGBE_AUTOC_AN_RX_LOOSE 0x01000000
@@ -1404,6 +1406,8 @@
 #define IXGBE_LINK_UP_TIME      90 /* 9.0 Seconds */
 #define IXGBE_AUTO_NEG_TIME     45 /* 4.5 Seconds */
 
+#define IXGBE_LINKS2_AN_SUPPORTED   0x00000040
+
 /* PCS1GLSTA Bit Masks */
 #define IXGBE_PCS1GLSTA_LINK_OK         1
 #define IXGBE_PCS1GLSTA_SYNK_OK         0x10
@@ -1424,6 +1428,11 @@
 #define IXGBE_PCS1GLCTL_AN_ENABLE       0x10000
 #define IXGBE_PCS1GLCTL_AN_RESTART      0x20000
 
+/* ANLP1 Bit Masks */
+#define IXGBE_ANLP1_PAUSE               0x0C00
+#define IXGBE_ANLP1_SYM_PAUSE           0x0400
+#define IXGBE_ANLP1_ASM_PAUSE           0x0800
+
 /* SW Semaphore Register bitmasks */
 #define IXGBE_SWSM_SMBI 0x00000001 /* Driver Semaphore bit */
 #define IXGBE_SWSM_SWESMBI 0x00000002 /* FW Semaphore bit */