rtl8224: wait for the PHY to answer instead of a fixed 2.5 s

rtl8224_enable() waits 2.5 s after releasing the RTL8224 reset before
anything talks to the PHY. On an SWTGW218AS the chip id already reads
back 0x8224 at the first poll, about 265 ms after the release.

Remember when the reset was released and, once SMI is up, poll the chip
id until it answers, giving up after the same 2.5 s as before. The PHY
writes that follow read back the same as before.

The reset pulse before it goes from 0.5 s to 20 ms, twice the 10 ms the
related RTL8372 and RTL8221B need. The pulse does reset the chip: the
MDI reverse register (MMD 30, 0x0a90) still reads its power-on value
0x00f3 just before the init writes 0x00fc, as it does with 0.5 s.
Together the console banner comes 3 s sooner.

The SerDes write loop in phy_config_8224() waited on the busy bit with
no limit, so a PHY that never answers stopped the boot before the
network came up. Bound it and report a timeout.

rtl837x_phy.c

@@ -23,6 +23,8 @@
 extern __code const uint16_t bit_mask[16];
 extern __code const struct machine machine;
 extern __xdata struct machine_runtime machine_detected;
+extern volatile __xdata uint32_t ticks;
+extern __xdata uint32_t rtl8224_release_tick;
 
 __xdata struct phy_settings phy_settings;
 
@@ -214,9 +216,20 @@ void phy_config(uint8_t phy) __banked
 }
 
 
+void rtl8224_wait_ready(void) __banked
+{
+	do {
+		rtl8224_read_reg_u16(RTL837X_REG_CHIP_ID + 1);
+		if (SFR_DATA_U16 == 0x8224)
+			return;
+	} while ((ticks - rtl8224_release_tick) < (SYS_TICK_HZ * 5 / 2));
+	print_string("\r\nRTL8224 not responding\r\n");
+}
+
 void phy_config_8224(void) __banked
 {
 	uint16_t pval;
+	uint16_t tries;
 	print_string("\r\nphy_config_8224 called\r\nRTL8224 ID: ");
 
 	// Print RTL8224 chip id
@@ -244,9 +257,12 @@ void phy_config_8224(void) __banked
 		i++;
 		rtl8224_write_reg_u16(RTL837X_SDS_INDACS_CMD, rtl8224_sds0_setttings[i]);
 		i++;
+		tries = 0xffff;
 		do {
 			rtl8224_read_reg_u16(0x3f8);
-		} while (SFR_DATA_8 & 0x80);
+		} while ((SFR_DATA_8 & 0x80) && --tries);
+		if (SFR_DATA_8 & 0x80)
+			print_string("\r\nRTL8224 SerDes access timed out\r\n");
 	}
 
 	print_string("\r\nphy_config_8224 done\r\n");