From 8d84e3804a691f4b08369f86840db0996ee78e3d Mon Sep 17 00:00:00 2001
From: Alan Cox <alan@linux.intel.com>
Date: Sat, 25 Aug 2018 19:13:59 +0100
Subject: [PATCH] sbcv2: initial basic PropIO probe

Use the uart console if we have no PropIO, otherwise default to the PropIO
---
 Kernel/platform-sbcv2/sbcv2.s | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/Kernel/platform-sbcv2/sbcv2.s b/Kernel/platform-sbcv2/sbcv2.s
index 925713b4..a061855b 100644
--- a/Kernel/platform-sbcv2/sbcv2.s
+++ b/Kernel/platform-sbcv2/sbcv2.s
@@ -79,6 +79,15 @@ _platform_reboot:
 init_early:
 	    ; FIXME: code goes here to check for PropIO v2 nicely
 	    ; Passes the minimal checking
+	    ld a,#0xA5
+	    out (0xAB),a		; Write A5 data
+	    ld a,#0x55
+	    out (0xAB),a		; Overwrite
+	    ld a,#0x00
+	    out (0xAA),a		; Issue a NOP
+	    in a,(0xAB)
+	    cp #0xA5			; Should see byte 1 again
+	    ret nz
 	    ld hl,#0x0102
 	    ld (_ttymap+1), hl		; set tty map to 0,2,1 for prop
 	    ret
-- 
2.34.1