Commit d51e86c1 authored by Stefan Richter's avatar Stefan Richter Committed by Jody McIntyre
Browse files

ieee1394: write broadcast_channel only to select nodes (fixes device recognition) 

Some old 1394-1995 SBP-2 bridges would hang if they received a broadcast write
request to BROADCAST_CHANNEL before the config ROM was read.  Affected devices
include Datafab MD2-FW2 2.5" HDD and SmartDisk VST FWCDRW-V8 portable CD writer.
The write request is now directed to specific nodes instead of being broadcast
to all nodes at once, and it is only performed if a previous read request at
this register succeeded.

Fixes an old interoperability problem which was perceived as a 2.6.14-specific
regression: http://marc.theaimsgroup.com/?t=113190586800003



Signed-off-by: default avatarStefan Richter <stefanr@s5r6.in-berlin.de>
Signed-off-by: default avatarJody McIntyre <scjody@modernduck.com>
(cherry picked from 61c7f775 commit)
parent 48622b7b

drivers/ieee1394/nodemgr.c

+32 −10
Original line number Diff line number Diff line
@@ -1349,6 +1349,33 @@ static void nodemgr_update_pdrv(struct node_entry *ne) 
}





/* Write the BROADCAST_CHANNEL as per IEEE1394a 8.3.2.3.11 and 8.4.2.3.  This

 * seems like an optional service but in the end it is practically mandatory

 * as a consequence of these clauses.

 *

 * Note that we cannot do a broadcast write to all nodes at once because some

 * pre-1394a devices would hang. */

static void nodemgr_irm_write_bc(struct node_entry *ne, int generation)

{

	const u64 bc_addr = (CSR_REGISTER_BASE | CSR_BROADCAST_CHANNEL);

	quadlet_t bc_remote, bc_local;

	int ret;



	if (!ne->host->is_irm || ne->generation != generation ||

	    ne->nodeid == ne->host->node_id)

		return;



	bc_local = cpu_to_be32(ne->host->csr.broadcast_channel);



	/* Check if the register is implemented and 1394a compliant. */

	ret = hpsb_read(ne->host, ne->nodeid, generation, bc_addr, &bc_remote,

			sizeof(bc_remote));

	if (!ret && bc_remote & cpu_to_be32(0x80000000) &&

	    bc_remote != bc_local)

		hpsb_node_write(ne, bc_addr, &bc_local, sizeof(bc_local));

}





static void nodemgr_probe_ne(struct host_info *hi, struct node_entry *ne, int generation)

{

	struct device *dev;
@@ -1360,6 +1387,8 @@ static void nodemgr_probe_ne(struct host_info *hi, struct node_entry *ne, int ge 
	if (!dev)

		return;



	nodemgr_irm_write_bc(ne, generation);



	/* If "needs_probe", then this is either a new or changed node we

	 * rescan totally. If the generation matches for an existing node

	 * (one that existed prior to the bus reset) we send update calls
@@ -1431,9 +1460,7 @@ static int nodemgr_send_resume_packet(struct hpsb_host *host) 
	return ret;

}



/* Because we are a 1394a-2000 compliant IRM, we need to inform all the other

 * nodes of the broadcast channel.  (Really we're only setting the validity

 * bit). Other IRM responsibilities go in here as well. */

/* Perform a few high-level IRM responsibilities. */

static int nodemgr_do_irm_duties(struct hpsb_host *host, int cycles)

{

	quadlet_t bc;
@@ -1442,13 +1469,8 @@ static int nodemgr_do_irm_duties(struct hpsb_host *host, int cycles) 
	if (!host->is_irm || host->irm_id == (nodeid_t)-1)

		return 1;



	host->csr.broadcast_channel |= 0x40000000;  /* set validity bit */



	bc = cpu_to_be32(host->csr.broadcast_channel);



	hpsb_write(host, LOCAL_BUS | ALL_NODES, get_hpsb_generation(host),

		   (CSR_REGISTER_BASE | CSR_BROADCAST_CHANNEL),

		   &bc, sizeof(quadlet_t));

	/* We are a 1394a-2000 compliant IRM. Set the validity bit. */

	host->csr.broadcast_channel |= 0x40000000;



	/* If there is no bus manager then we should set the root node's

	 * force_root bit to promote bus stability per the 1394

CRA Git | Maintained and supported by SUSTech CRA and CCSE