macintosh/adb-iop: Use big-endian autopoll mask

As usual, the available documentation is inadequate and leaves endianness
unspecified for message data. However, testing shows that this patch does
improve correctness. The mistake should have been detected earlier but it
was obscured by other bugs. In testing, this patch reinstated pre-v5.9
behaviour. The old driver bugs remain and ADB input devices may stop
working. But that appears to be unrelated.

Cc: Joshua Thompson <funaho@jurai.org>
Fixes: c66da95a39ec ("macintosh/adb-iop: Implement SRQ autopolling")
Tested-by: Stan Johnson <userm57@yahoo.com>
Signed-off-by: Finn Thain <fthain@telegraphics.com.au>
Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
Link: https://lore.kernel.org/r/20210125074524.3027452-1-geert@linux-m68k.org

diff --git a/drivers/macintosh/adb-iop.c b/drivers/macintosh/adb-iop.c
index 0ee3272491501c522012a8d8062215d660cfc245..2633bc254935cc49110c97f5e8a7eed223ee4292 100644 (file)
--- a/drivers/macintosh/adb-iop.c
+++ b/drivers/macintosh/adb-iop.c
@@ -19,6 +19,7 @@
 #include <asm/macints.h>
 #include <asm/mac_iop.h>
 #include <asm/adb_iop.h>
+#include <asm/unaligned.h>
 
 #include <linux/adb.h>
 
@@ -249,7 +250,7 @@ static void adb_iop_set_ap_complete(struct iop_msg *msg)
 {
        struct adb_iopmsg *amsg = (struct adb_iopmsg *)msg->message;
 
-       autopoll_devs = (amsg->data[1] << 8) | amsg->data[0];
+       autopoll_devs = get_unaligned_be16(amsg->data);
        if (autopoll_devs & (1 << autopoll_addr))
                return;
        autopoll_addr = autopoll_devs ? (ffs(autopoll_devs) - 1) : 0;
@@ -266,8 +267,7 @@ static int adb_iop_autopoll(int devs)
        amsg.flags = ADB_IOP_SET_AUTOPOLL | (mask ? ADB_IOP_AUTOPOLL : 0);
        amsg.count = 2;
        amsg.cmd = 0;
-       amsg.data[0] = mask & 0xFF;
-       amsg.data[1] = (mask >> 8) & 0xFF;
+       put_unaligned_be16(mask, amsg.data);
 
        iop_send_message(ADB_IOP, ADB_CHAN, NULL, sizeof(amsg), (__u8 *)&amsg,
                         adb_iop_set_ap_complete);