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>
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@ -173,7 +173,8 @@ struct sbp2_target {
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#define SBP2_ORB_TIMEOUT 2000U /* Timeout in ms */
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#define SBP2_ORB_NULL 0x80000000
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#define SBP2_MAX_SG_ELEMENT_LENGTH 0xf000
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#define SBP2_RETRY_LIMIT 0xf /* 15 retries */
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#define SBP2_RETRY_LIMIT 0xf /* 15 retries */
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#define SBP2_CYCLE_LIMIT (0xc8 << 12) /* 200 125us cycles */
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/* Unit directory keys */
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#define SBP2_CSR_UNIT_CHARACTERISTICS 0x3a
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@ -813,6 +814,22 @@ complete_set_busy_timeout(struct fw_card *card, int rcode,
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complete(done);
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}
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/*
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* Write retransmit retry values into the BUSY_TIMEOUT register.
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* - The single-phase retry protocol is supported by all SBP-2 devices, but the
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* default retry_limit value is 0 (i.e. never retry transmission). We write a
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* saner value after logging into the device.
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* - The dual-phase retry protocol is optional to implement, and if not
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* supported, writes to the dual-phase portion of the register will be
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* ignored. We try to write the original 1394-1995 default here.
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* - In the case of devices that are also SBP-3-compliant, all writes are
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* ignored, as the register is read-only, but contains single-phase retry of
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* 15, which is what we're trying to set for all SBP-2 device anyway, so this
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* write attempt is safe and yields more consistent behavior for all devices.
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*
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* See section 8.3.2.3.5 of the 1394-1995 spec, section 6.2 of the SBP-2 spec,
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* and section 6.4 of the SBP-3 spec for further details.
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*/
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static void sbp2_set_busy_timeout(struct sbp2_logical_unit *lu)
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{
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struct fw_device *device = fw_device(lu->tgt->unit->device.parent);
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@ -820,8 +837,7 @@ static void sbp2_set_busy_timeout(struct sbp2_logical_unit *lu)
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struct fw_transaction t;
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static __be32 busy_timeout;
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/* FIXME: we should try to set dual-phase cycle_limit too */
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busy_timeout = cpu_to_be32(SBP2_RETRY_LIMIT);
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busy_timeout = cpu_to_be32(SBP2_CYCLE_LIMIT | SBP2_RETRY_LIMIT);
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fw_send_request(device->card, &t, TCODE_WRITE_QUADLET_REQUEST,
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lu->tgt->node_id, lu->generation, device->max_speed,
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