[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.

[akpm@osdl.org: cleanups]
Signed-off-by: NDirk Eibach <eibach@gdsys.de>
Acked-by: NAlan Cox <alan@redhat.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

drivers/char/moxa.c

@@ -142,6 +142,7 @@ typedef struct _moxa_board_conf {
 
 static moxa_board_conf moxa_boards[MAX_BOARDS];
 static void __iomem *moxaBaseAddr[MAX_BOARDS];
+static int loadstat[MAX_BOARDS];
 
 struct moxa_str {
 	int type;
@@ -1688,6 +1689,8 @@ int MoxaDriverPoll(void)
 	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) {
@@ -2903,6 +2906,7 @@ static int moxaloadcode(int cardno, unsigned char __user *tmp, int len)
 		}
 		break;
 	}
+	loadstat[cardno] = 1;
 	return (0);
 }
 
@@ -2920,7 +2924,7 @@ static int moxaloadc218(int cardno, void __iomem *baseAddr, int len)
 	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;
@@ -2992,7 +2996,7 @@ static int moxaloadc320(int cardno, void __iomem *baseAddr, int len, int *numPor
 	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 {