[PATCH 2/7] net/ixgbe: Add ixgbe_check_sfp_cage() for testing state of PRSNT# signal

[Stephen Douthit <stephend@silicom-usa.com>]

Refactor the SFP check code from ixgbe_check_mac_link_generic into its own
function.

Note that the SFP present status was inverted for the X550EM family of
devices, where SDP0 represents the active low PRSNT# signal from the cage.

Call the new function in ixgbe_identify_module_generic() to short circuit
the I2C polling and greatly speed things up for devices we know are
absent.

Fixes: dd3a93cf5a2 ("net/ixgbe/base: bypass checking link for crosstalk")
Cc: stable@dpdk.org

Signed-off-by: Stephen Douthit <stephend@silicom-usa.com>
---
 drivers/net/ixgbe/base/ixgbe_common.c | 60 +++++++++++++++++++--------
 drivers/net/ixgbe/base/ixgbe_common.h |  8 ++++
 drivers/net/ixgbe/base/ixgbe_phy.c    |  8 ++++
 3 files changed, 58 insertions(+), 18 deletions(-)

diff --git a/drivers/net/ixgbe/base/ixgbe_common.c b/drivers/net/ixgbe/base/ixgbe_common.c
index aa843bd5c4..2764cf7cf1 100644
--- a/drivers/net/ixgbe/base/ixgbe_common.c
+++ b/drivers/net/ixgbe/base/ixgbe_common.c
@@ -4124,6 +4124,45 @@ static bool ixgbe_need_crosstalk_fix(struct ixgbe_hw *hw)
 	return true;
 }
 
+/**
+ * ixgbe_check_sfp_cage - Find present status of SFP module
+ * @hw: pointer to hardware structure
+ *
+ * Find if a SFP module is present and if this device supports SFPs
+ **/
+enum ixgbe_sfp_cage_status ixgbe_check_sfp_cage(struct ixgbe_hw *hw)
+{
+	enum ixgbe_sfp_cage_status status;
+
+	/* If we're not a fiber/fiber_qsfp, no cage to check */
+	switch (hw->mac.ops.get_media_type(hw)) {
+	case ixgbe_media_type_fiber:
+	case ixgbe_media_type_fiber_qsfp:
+		break;
+	default:
+		return IXGBE_SFP_CAGE_NOCAGE;
+	}
+
+	switch (hw->mac.type) {
+	case ixgbe_mac_82599EB:
+		status = !!(IXGBE_READ_REG(hw, IXGBE_ESDP) &
+			     IXGBE_ESDP_SDP2);
+		break;
+	case ixgbe_mac_X550EM_x:
+	case ixgbe_mac_X550EM_a:
+		/* SDP0 is the active low signal PRSNT#, so invert this */
+		status = !(IXGBE_READ_REG(hw, IXGBE_ESDP) &
+				  IXGBE_ESDP_SDP0);
+		break;
+	default:
+		/* Don't know how to check this device type yet */
+		status = IXGBE_SFP_CAGE_UNKNOWN;
+		break;
+	}
+
+	return status;
+}
+
 /**
  * ixgbe_check_mac_link_generic - Determine link and speed status
  * @hw: pointer to hardware structure
@@ -4145,25 +4184,10 @@ s32 ixgbe_check_mac_link_generic(struct ixgbe_hw *hw, ixgbe_link_speed *speed,
 	 * the SFP+ cage is full.
 	 */
 	if (ixgbe_need_crosstalk_fix(hw)) {
-		u32 sfp_cage_full;
-
-		switch (hw->mac.type) {
-		case ixgbe_mac_82599EB:
-			sfp_cage_full = IXGBE_READ_REG(hw, IXGBE_ESDP) &
-					IXGBE_ESDP_SDP2;
-			break;
-		case ixgbe_mac_X550EM_x:
-		case ixgbe_mac_X550EM_a:
-			sfp_cage_full = IXGBE_READ_REG(hw, IXGBE_ESDP) &
-					IXGBE_ESDP_SDP0;
-			break;
-		default:
-			/* sanity check - No SFP+ devices here */
-			sfp_cage_full = false;
-			break;
-		}
+		enum ixgbe_sfp_cage_status sfp_cage_status;
 
-		if (!sfp_cage_full) {
+		sfp_cage_status = ixgbe_check_sfp_cage(hw);
+		if (sfp_cage_status != IXGBE_SFP_CAGE_FULL) {
 			*link_up = false;
 			*speed = IXGBE_LINK_SPEED_UNKNOWN;
 			return IXGBE_SUCCESS;
diff --git a/drivers/net/ixgbe/base/ixgbe_common.h b/drivers/net/ixgbe/base/ixgbe_common.h
index 5bdb484407..30db9a08c4 100644
--- a/drivers/net/ixgbe/base/ixgbe_common.h
+++ b/drivers/net/ixgbe/base/ixgbe_common.h
@@ -112,6 +112,14 @@ s32 ixgbe_set_vlvf_generic(struct ixgbe_hw *hw, u32 vlan, u32 vind,
 s32 ixgbe_clear_vfta_generic(struct ixgbe_hw *hw);
 s32 ixgbe_find_vlvf_slot(struct ixgbe_hw *hw, u32 vlan, bool vlvf_bypass);
 
+enum ixgbe_sfp_cage_status {
+	IXGBE_SFP_CAGE_EMPTY = 0,
+	IXGBE_SFP_CAGE_FULL,
+	IXGBE_SFP_CAGE_UNKNOWN = -1,
+	IXGBE_SFP_CAGE_NOCAGE = -2,
+};
+enum ixgbe_sfp_cage_status ixgbe_check_sfp_cage(struct ixgbe_hw *hw);
+
 s32 ixgbe_check_mac_link_generic(struct ixgbe_hw *hw,
 			       ixgbe_link_speed *speed,
 			       bool *link_up, bool link_up_wait_to_complete);
diff --git a/drivers/net/ixgbe/base/ixgbe_phy.c b/drivers/net/ixgbe/base/ixgbe_phy.c
index 8d4d9bbfef..d8d51d2c3f 100644
--- a/drivers/net/ixgbe/base/ixgbe_phy.c
+++ b/drivers/net/ixgbe/base/ixgbe_phy.c
@@ -1228,9 +1228,17 @@ s32 ixgbe_reset_phy_nl(struct ixgbe_hw *hw)
 s32 ixgbe_identify_module_generic(struct ixgbe_hw *hw)
 {
 	s32 status = IXGBE_ERR_SFP_NOT_PRESENT;
+	enum ixgbe_sfp_cage_status sfp_cage_status;
 
 	DEBUGFUNC("ixgbe_identify_module_generic");
 
+	sfp_cage_status = ixgbe_check_sfp_cage(hw);
+	if (sfp_cage_status == IXGBE_SFP_CAGE_EMPTY ||
+	    sfp_cage_status == IXGBE_SFP_CAGE_NOCAGE) {
+		hw->phy.sfp_type = ixgbe_sfp_type_not_present;
+		return status;
+	}
+
 	switch (hw->mac.ops.get_media_type(hw)) {
 	case ixgbe_media_type_fiber:
 		status = ixgbe_identify_sfp_module_generic(hw);
-- 
2.31.1