[PATCH 4/4 resend] ohci1394, sbp2: fix "scsi_add_device failed" with PL-3507 based devices

[Stefan Richter <stefanr@s5r6.in-berlin.de>]

Re-enable posted writes for status FIFO.
Besides bringing back a very minor bandwidth tweak from Linux 2.6.15.x
and older, this also fixes an interoperability regression since 2.6.16:
http://bugzilla.kernel.org/show_bug.cgi?id=6356
(sbp2: scsi_add_device failed. IEEE1394 HD is not working anymore.)

Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
Tested-by: Vanei Heidemann <linux@javanei.com.br>
Tested-by: Martin Putzlocher <mputzi@gmx.de> (chip type unconfirmed)
---
The ugly hardwired PhyUpperBound which this patch (re-)introduces into
sbp2 will be eliminated by a subsequent patchset which has already been
sent to linux1394-devel.

First posted on 2006-04-23.

Index: linux-2.6.17-rc4/drivers/ieee1394/ohci1394.c
===================================================================
--- linux-2.6.17-rc4.orig/drivers/ieee1394/ohci1394.c	2006-05-15 21:27:04.000000000 +0200
+++ linux-2.6.17-rc4/drivers/ieee1394/ohci1394.c	2006-05-15 21:52:42.000000000 +0200
@@ -553,7 +553,7 @@ static void ohci_initialize(struct ti_oh
 	 * register content.
 	 * To actually enable physical responses is the job of our interrupt
 	 * handler which programs the physical request filter. */
-	reg_write(ohci, OHCI1394_PhyUpperBound, 0xffff0000);
+	reg_write(ohci, OHCI1394_PhyUpperBound, 0x01000000);
 
 	DBGMSG("physUpperBoundOffset=%08x",
 	       reg_read(ohci, OHCI1394_PhyUpperBound));
Index: linux-2.6.17-rc4/drivers/ieee1394/sbp2.c
===================================================================
--- linux-2.6.17-rc4.orig/drivers/ieee1394/sbp2.c	2006-05-15 21:52:18.000000000 +0200
+++ linux-2.6.17-rc4/drivers/ieee1394/sbp2.c	2006-05-15 21:52:42.000000000 +0200
@@ -835,11 +835,16 @@ static struct scsi_id_instance_data *sbp
 
 	/* Register the status FIFO address range. We could use the same FIFO
 	 * for targets at different nodes. However we need different FIFOs per
-	 * target in order to support multi-unit devices. */
+	 * target in order to support multi-unit devices.
+	 * The FIFO is located out of the local host controller's physical range
+	 * but, if possible, within the posted write area. Status writes will
+	 * then be performed as unified transactions. This slightly reduces
+	 * bandwidth usage, and some Prolific based devices seem to require it.
+	 */
 	scsi_id->status_fifo_addr = hpsb_allocate_and_register_addrspace(
 			&sbp2_highlevel, ud->ne->host, &sbp2_ops,
 			sizeof(struct sbp2_status_block), sizeof(quadlet_t),
-			~0ULL, ~0ULL);
+			0x010000000000ULL, CSR1212_ALL_SPACE_END);
 	if (!scsi_id->status_fifo_addr) {
 		SBP2_ERR("failed to allocate status FIFO address range");
 		goto failed_alloc;