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firewire: fw-sbp2: set dual-phase cycle_limit 

Try to write dual-phase retry protocol limits to BUSY_TIMEOUT register.
- The dual-phase retry protocol is optional to implement, and if not 
  supported, writes to the dual-phase portion of the register will be
  ignored. We try to write the original 1394-1995 default here.
- In the case of devices that are also SBP-3-compliant, all writes are 
  ignored, as the register is read-only, but contains single-phase retry of
  15, which is what we're trying to set for all SBP-2 device anyway, so this
  write attempt is safe and yields more consistent behavior for all devices.

See section 8.3.2.3.5 of the 1394-1995 spec, section 6.2 of the SBP-2 spec,
and section 6.4 of the SBP-3 spec for further details.

Signed-off-by: Jarod Wilson <jwilson@redhat.com>
Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
This commit is contained in:
Jarod Wilson 2008-03-07 01:43:31 -05:00 committed by Stefan Richter
parent a5fd9ec7a2
commit 17cff9ff87
1 changed files with 19 additions and 3 deletions
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20
drivers/firewire/fw-sbp2.c
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@ -174,6 +174,7 @@ struct sbp2_target {
#define SBP2_ORB_NULL 0x80000000
#define SBP2_MAX_SG_ELEMENT_LENGTH 0xf000
#define SBP2_RETRY_LIMIT 0xf /* 15 retries */
#define SBP2_CYCLE_LIMIT (0xc8 << 12) /* 200 125us cycles */
/* Unit directory keys */
#define SBP2_CSR_UNIT_CHARACTERISTICS 0x3a
@ -813,6 +814,22 @@ complete_set_busy_timeout(struct fw_card *card, int rcode,
complete(done);
}
/*
* Write retransmit retry values into the BUSY_TIMEOUT register.
* - The single-phase retry protocol is supported by all SBP-2 devices, but the
* default retry_limit value is 0 (i.e. never retry transmission). We write a
* saner value after logging into the device.
* - The dual-phase retry protocol is optional to implement, and if not
* supported, writes to the dual-phase portion of the register will be
* ignored. We try to write the original 1394-1995 default here.
* - In the case of devices that are also SBP-3-compliant, all writes are
* ignored, as the register is read-only, but contains single-phase retry of
* 15, which is what we're trying to set for all SBP-2 device anyway, so this
* write attempt is safe and yields more consistent behavior for all devices.
*
* See section 8.3.2.3.5 of the 1394-1995 spec, section 6.2 of the SBP-2 spec,
* and section 6.4 of the SBP-3 spec for further details.
*/
static void sbp2_set_busy_timeout(struct sbp2_logical_unit *lu)
{
struct fw_device *device = fw_device(lu->tgt->unit->device.parent);
@ -820,8 +837,7 @@ static void sbp2_set_busy_timeout(struct sbp2_logical_unit *lu)
struct fw_transaction t;
static __be32 busy_timeout;
/* FIXME: we should try to set dual-phase cycle_limit too */
busy_timeout = cpu_to_be32(SBP2_RETRY_LIMIT);
busy_timeout = cpu_to_be32(SBP2_CYCLE_LIMIT | SBP2_RETRY_LIMIT);
fw_send_request(device->card, &t, TCODE_WRITE_QUADLET_REQUEST,
lu->tgt->node_id, lu->generation, device->max_speed,