[PATCH] pcmcia: enable read prefetch on o2micro bridges to fix HDSP

enable read prefetching on O2micro bridges. It fixes the problems
seen with the RME Hammerfall DSP.
Thanks to Eric Still from O2micro for the input.

Cc: Russell King <rmk@arm.linux.org.uk>
Signed-off-by: Daniel Ritz <daniel.ritz@gmx.ch>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

drivers/pcmcia/i82365.c

@@ -65,7 +65,6 @@
 #include "cirrus.h"
 #include "vg468.h"
 #include "ricoh.h"
-#include "o2micro.h"
 
 #ifdef DEBUG
 static const char version[] =

drivers/pcmcia/o2micro.h

@@ -120,4 +120,30 @@
 #define  O2_MODE_E_LED_OUT	0x08
 #define  O2_MODE_E_SKTA_ACTV	0x10
 
+static int o2micro_override(struct yenta_socket *socket)
+{
+	/*
+	 * 'reserved' register at 0x94/D4. chaning it to 0xCA (8 bit) enables
+	 * read prefetching which for example makes the RME Hammerfall DSP
+	 * working. for some bridges it is at 0x94, for others at 0xD4. it's
+	 * ok to write to both registers on all O2 bridges.
+	 * from Eric Still, 02Micro.
+	 */
+	if (PCI_FUNC(socket->dev->devfn) == 0) {
+		config_writeb(socket, 0x94, 0xCA);
+		config_writeb(socket, 0xD4, 0xCA);
+	}
+
+	return 0;
+}
+
+static void o2micro_restore_state(struct yenta_socket *socket)
+{
+	/*
+	 * as long as read prefetch is the only thing in
+	 * o2micro_override, it's safe to call it from here
+	 */
+	o2micro_override(socket);
+}
+
 #endif /* _LINUX_O2MICRO_H */

drivers/pcmcia/yenta_socket.c

@@ -668,6 +668,7 @@ static struct pccard_operations yenta_socket_operations = {
 #include "ti113x.h"
 #include "ricoh.h"
 #include "topic.h"
+#include "o2micro.h"
 
 enum {
 	CARDBUS_TYPE_DEFAULT = -1,
@@ -676,7 +677,8 @@ enum {
 	CARDBUS_TYPE_TI12XX,
 	CARDBUS_TYPE_TI1250,
 	CARDBUS_TYPE_RICOH,
-	CARDBUS_TYPE_TOPIC97
+	CARDBUS_TYPE_TOPIC97,
+	CARDBUS_TYPE_O2MICRO,
 };
 
 /*
@@ -716,6 +718,10 @@ struct cardbus_type cardbus_type[] = {
 	[CARDBUS_TYPE_TOPIC97]	= {
 		.override	= topic97_override,
 	},
+	[CARDBUS_TYPE_O2MICRO]	= {
+		.override	= o2micro_override,
+		.restore_state	= o2micro_restore_state,
+	},
 };
 
 
@@ -1100,6 +1106,8 @@ static struct pci_device_id yenta_table [] = {
 	CB_ID(PCI_VENDOR_ID_TOSHIBA, PCI_DEVICE_ID_TOSHIBA_TOPIC97, TOPIC97),
 	CB_ID(PCI_VENDOR_ID_TOSHIBA, PCI_DEVICE_ID_TOSHIBA_TOPIC100, TOPIC97),
 
+	CB_ID(PCI_VENDOR_ID_O2, PCI_ANY_ID, O2MICRO),
+
 	/* match any cardbus bridge */
 	CB_ID(PCI_ANY_ID, PCI_ANY_ID, DEFAULT),
 	{ /* all zeroes */ }