ieee1394: ignore nonzero Bus_Info_Block.max_rom, fetch config ROM in quadlets

It is already known that buggy firmwares exist which report a bogus
link_spd in their config ROM bus info block.  We now got the first
report of a bogus max_rom too (Freecom FireWire Hard Drive 1TB,
http://bugzilla.kernel.org/show_bug.cgi?id=12206).

I suspect other OSs only use quadlet reads to fetch the config ROM,
otherwise the firmware authors would have noticed their mistake.
Hence limit ieee1394's config ROM fetching routine to quadlets as the
safe minimum regardless of what the bus info block says.

This will potentially slow the bus reset handling by nodemgr somewhat
down.  But most existing devices support only quadlet reads anyway,
hence there will often be no actual difference to before this change.

Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>

1 files changed, 4 insertions, 16 deletions

diff --git a/drivers/ieee1394/nodemgr.c b/drivers/ieee1394/nodemgr.c
index 79ef5fd928ae..906c5a98d814 100644
--- a/drivers/ieee1394/nodemgr.c
+++ b/drivers/ieee1394/nodemgr.c
@@ -67,7 +67,7 @@ static int nodemgr_check_speed(struct nodemgr_csr_info *ci, u64 addr,
 	for (i = IEEE1394_SPEED_100; i <= old_speed; i++) {
 		*speed = i;
 		error = hpsb_read(ci->host, ci->nodeid, ci->generation, addr,
-				  &q, sizeof(quadlet_t));
+				  &q, 4);
 		if (error)
 			break;
 		*buffer = q;
@@ -85,7 +85,7 @@ static int nodemgr_check_speed(struct nodemgr_csr_info *ci, u64 addr,
 	return error;
 }
 
-static int nodemgr_bus_read(struct csr1212_csr *csr, u64 addr, u16 length,
+static int nodemgr_bus_read(struct csr1212_csr *csr, u64 addr,
 			    void *buffer, void *__ci)
 {
 	struct nodemgr_csr_info *ci = (struct nodemgr_csr_info*)__ci;
@@ -93,7 +93,7 @@ static int nodemgr_bus_read(struct csr1212_csr *csr, u64 addr, u16 length,
 
 	for (i = 1; ; i++) {
 		error = hpsb_read(ci->host, ci->nodeid, ci->generation, addr,
-				  buffer, length);
+				  buffer, 4);
 		if (!error) {
 			ci->speed_unverified = 0;
 			break;
@@ -104,7 +104,7 @@ static int nodemgr_bus_read(struct csr1212_csr *csr, u64 addr, u16 length,
 
 		/* The ieee1394_core guessed the node's speed capability from
 		 * the self ID.  Check whether a lower speed works. */
-		if (ci->speed_unverified && length == sizeof(quadlet_t)) {
+		if (ci->speed_unverified) {
 			error = nodemgr_check_speed(ci, addr, buffer);
 			if (!error)
 				break;
@@ -115,20 +115,8 @@ static int nodemgr_bus_read(struct csr1212_csr *csr, u64 addr, u16 length,
 	return error;
 }
 
-#define OUI_FREECOM_TECHNOLOGIES_GMBH 0x0001db
-
-static int nodemgr_get_max_rom(quadlet_t *bus_info_data, void *__ci)
-{
-	/* Freecom FireWire Hard Drive firmware bug */
-	if (be32_to_cpu(bus_info_data[3]) >> 8 == OUI_FREECOM_TECHNOLOGIES_GMBH)
-		return 0;
-
-	return (be32_to_cpu(bus_info_data[2]) >> 8) & 0x3;
-}
-
 static struct csr1212_bus_ops nodemgr_csr_ops = {
 	.bus_read =	nodemgr_bus_read,
-	.get_max_rom =	nodemgr_get_max_rom
 };