[src/trunk]: src/sys/dev/adb now that I figured out how the checksum for the ...

[macallan <macallan%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/5754baff10a7
branches:  trunk
changeset: 454122:5754baff10a7
user:      macallan <macallan%NetBSD.org@localhost>
date:      Thu Sep 05 21:29:22 2019 +0000

description:
now that I figured out how the checksum for the Kensington Turbo Mouse's
init command works:
- document it
- calculate the checksum instead of hardcoding it, so the init command can be
  easily changed
- drop the first init string - it's entirely overwritten by the 2nd
- remove some debug goop

diffstat:

 sys/dev/adb/adb_ms.c |  49 ++++++++++++++++++-------------------------------
 1 files changed, 18 insertions(+), 31 deletions(-)

diffs (88 lines):

diff -r cd36e52dbec3 -r 5754baff10a7 sys/dev/adb/adb_ms.c
--- a/sys/dev/adb/adb_ms.c      Thu Sep 05 20:17:27 2019 +0000
+++ b/sys/dev/adb/adb_ms.c      Thu Sep 05 21:29:22 2019 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: adb_ms.c,v 1.18 2019/08/31 02:14:51 macallan Exp $     */
+/*     $NetBSD: adb_ms.c,v 1.19 2019/09/05 21:29:22 macallan Exp $     */
 
 /*
  * Copyright (C) 1998  Colin Wood
@@ -32,7 +32,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: adb_ms.c,v 1.18 2019/08/31 02:14:51 macallan Exp $");
+__KERNEL_RCSID(0, "$NetBSD: adb_ms.c,v 1.19 2019/09/05 21:29:22 macallan Exp $");
 
 #include <sys/param.h>
 #include <sys/device.h>
@@ -320,6 +320,16 @@
        sc->sc_res = 200;
 }
 
+static int
+adbms_turbo_csum(uint8_t *d)
+{
+       int i = 0, sum = 0;
+
+       for (i = 0; i < 7; i++)
+               sum ^= d[i];
+       return (sum ^ 0xff);
+}
+
 static void
 adbms_init_turbo(struct adbms_softc *sc)
 {
@@ -343,22 +353,13 @@
  - 0x21 - button 1 - 2, button 2 - 1
  - 0x31 - button 1 - 3, button 2 - 1
  * byte 4 programs a delay for button presses, apparently in 1/100 seconds
- * byte 7 is some sort of checksum, writes will only stick if it's valid
-          no idea how exactly it works yet, can't be too complicated considering
-          the device's age
+ * byte 7 is a simple XOR checksum, writes will only stick if it's valid
+          as in, b[7] = (b[0] ^ b[1] ^ ... ^ b[6]) ^ 0xff
  */
  
-/*
- * XXX
- * I doubt the first command is actually necessary. Leave in for now since it 
- * doesn't do any harm either
- */
-       static u_char data1[] =
-               { 0xe7, 0x8c, 0, 0, 0, 0xff, 0xff, 0x94 };
-
        /* this seems to be the most reasonable default */
-       static u_char data2[] =
-               { 0xa5, 0x0e, 0, 0, 1, 0xff, 0xff, 0x55 };
+       static u_char data[] =
+               { 0xa5, 0x0e, 0, 0, 1, 0xff, 0xff, 0/*0x55*/ };
 
        addr = sc->sc_adbdev->current_addr;
 
@@ -374,23 +375,9 @@
 #endif
 
        adbms_send_sync(sc, ADBFLUSH(addr), 0, NULL);
-       adbms_send_sync(sc, ADBLISTEN(addr, 2), 8, data1);
-       adbms_send_sync(sc, ADBFLUSH(addr), 0, NULL);
-       adbms_send_sync(sc, ADBLISTEN(addr, 2), 8, data2);
+       data[7] = adbms_turbo_csum(data);
+       adbms_send_sync(sc, ADBLISTEN(addr, 2), 8, data);
 
-#ifdef ADBMS_BRUTEFORCE
-       sc->sc_buffer[1] = 0;
-       int y = 0;
-       while ((sc->sc_buffer[1] != data2[1]) && (y < 0x100)) {
-               data2[7] = y;
-               y++;
-               adbms_send_sync(sc, ADBFLUSH(addr), 0, NULL);
-               adbms_send_sync(sc, ADBLISTEN(addr, 2), 8, data2);
-               adbms_send_sync(sc, ADBFLUSH(addr), 0, NULL);
-               adbms_send_sync(sc, ADBTALK(addr, 2), 0, NULL);
-       }
-       printf("y %02x\n", data2[7]);   
-#endif
 
 #ifdef ADBMS_DEBUG
        int i, reg;