From 6eb6a5892d9a8a139faecf30c09cb26a5982251c Mon Sep 17 00:00:00 2001
From: Maxim Poliakovski <maximumspatium@googlemail.com>
Date: Wed, 20 Sep 2023 00:44:08 +0200
Subject: [PATCH] bigmac: fix/improve PHY interface.

---
 devices/ethernet/bigmac.cpp | 11 +++++++++++
 devices/ethernet/bigmac.h   |  1 +
 2 files changed, 12 insertions(+)

diff --git a/devices/ethernet/bigmac.cpp b/devices/ethernet/bigmac.cpp
index 250cf56..dfe91c5 100644
--- a/devices/ethernet/bigmac.cpp
+++ b/devices/ethernet/bigmac.cpp
@@ -124,6 +124,9 @@ void BigMac::mii_rcv_bit() {
             this->mii_reset();
         }
         break;
+    case MII_FRAME_SM::Stop:
+        this->mii_reset();
+        break;
     default:
         LOG_F(ERROR, "%s: unhandled state %d in mii_rcv_bit", this->name.c_str(),
               this->mii_state);
@@ -245,6 +248,10 @@ void BigMac::phy_reset() {
 
 uint16_t BigMac::phy_reg_read(uint8_t reg_num) {
     switch(reg_num) {
+    case PHY_BMCR:
+        return this->phy_bmcr;
+    case PHY_BMSR:
+        return 0x7809; // value from LXT970 datasheet
     case PHY_ID1:
         return (this->phy_oui >> 6) & 0xFFFFU;
     case PHY_ID2:
@@ -261,6 +268,10 @@ uint16_t BigMac::phy_reg_read(uint8_t reg_num) {
 void BigMac::phy_reg_write(uint8_t reg_num, uint16_t value) {
     switch(reg_num) {
     case PHY_BMCR:
+        if (value & 0x8000) {
+            LOG_F(INFO, "PHY reset requested");
+            value &= ~0x8000; // Reset bit is self-clearing
+        }
         this->phy_bmcr = value;
         break;
     case PHY_ANAR:
diff --git a/devices/ethernet/bigmac.h b/devices/ethernet/bigmac.h
index ac5f8a1..fd83f2b 100644
--- a/devices/ethernet/bigmac.h
+++ b/devices/ethernet/bigmac.h
@@ -84,6 +84,7 @@ enum MII_FRAME_SM {
 /* PHY control/status registers. */
 enum {
     PHY_BMCR    = 0,
+    PHY_BMSR    = 1,
     PHY_ID1     = 2,
     PHY_ID2     = 3,
     PHY_ANAR    = 4,