[PATCH] char/moxa.c: fix endianess and multiple-card issues

While testing Moxa C218T/PCI on PowerPC 405EP I found that loading firmware
using the linux kernel driver fails because calculation of the checksum is
not endianess independent in the original code.

After I fixed this I found that uploading firmware in a system with
multiple cards causes a kernel oops. I had a look in the recent moxa
sources and found that they do some kind of locking there. Applying this
lock fixed the problem.

Alan sayeth:

Checksum changes are clearly correct. Other changes is an improvement but
not I think enough to handle malicious firmware attacks. That said such an
attacker has CAP_SYS_RAWIO anyway so that part is irrelevant except for
neatness.

[[e-mail]: cleanups]
Signed-off-by: Dirk Eibach <[e-mail]>
Acked-by: Alan Cox <[e-mail]>
Signed-off-by: Andrew Morton <[e-mail]>
Signed-off-by: Linus Torvalds <[e-mail]>

drivers/char/moxa.c

···
 
 static moxa_board_conf moxa_boards[MAX_BOARDS];
 static void __iomem *moxaBaseAddr[MAX_BOARDS];
+static int loadstat[MAX_BOARDS];
 
 struct moxa_str {
 	int type;
···
 	if (moxaCard == 0)
 		return (-1);
 	for (card = 0; card < MAX_BOARDS; card++) {
+	        if (loadstat[card] == 0)
+			continue;
 		if ((ports = moxa_boards[card].numPorts) == 0)
 			continue;
 		if (readb(moxaIntPend[card]) == 0xff) {
···
 		}
 		break;
 	}
+	loadstat[cardno] = 1;
 	return (0);
 }
 
···
 	len1 = len >> 1;
 	ptr = (ushort *) moxaBuff;
 	for (i = 0; i < len1; i++)
-		usum += *(ptr + i);
+		usum += le16_to_cpu(*(ptr + i));
 	retry = 0;
 	do {
 		len1 = len >> 1;
···
 	wlen = len >> 1;
 	uptr = (ushort *) moxaBuff;
 	for (i = 0; i < wlen; i++)
-		usum += uptr[i];
+		usum += le16_to_cpu(uptr[i]);
 	retry = 0;
 	j = 0;
 	do {