firewire: core: add CSR MAINT_UTILITY support
Implement the MAIN_UTILITY register, which is utterly optional
but useful as a safe target for diagnostic read/write/broadcast
transactions.
Signed-off-by: Clemens Ladisch <clemens@ladisch.de>
diff --git a/drivers/firewire/core-transaction.c b/drivers/firewire/core-transaction.c
index a61eb3f..dd8ef65 100644
--- a/drivers/firewire/core-transaction.c
+++ b/drivers/firewire/core-transaction.c
@@ -1140,6 +1140,15 @@
rcode = RCODE_TYPE_ERROR;
break;
+ case CSR_MAINT_UTILITY:
+ if (tcode == TCODE_READ_QUADLET_REQUEST)
+ *data = card->maint_utility_register;
+ else if (tcode == TCODE_WRITE_QUADLET_REQUEST)
+ card->maint_utility_register = *data;
+ else
+ rcode = RCODE_TYPE_ERROR;
+ break;
+
case CSR_BROADCAST_CHANNEL:
if (tcode == TCODE_READ_QUADLET_REQUEST)
*data = cpu_to_be32(card->broadcast_channel);