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>
diff --git a/drivers/firewire/fw-sbp2.c b/drivers/firewire/fw-sbp2.c
index 6255187..e99a33f 100644
--- a/drivers/firewire/fw-sbp2.c
+++ b/drivers/firewire/fw-sbp2.c
@@ -173,7 +173,8 @@
#define SBP2_ORB_TIMEOUT 2000U /* Timeout in ms */
#define SBP2_ORB_NULL 0x80000000
#define SBP2_MAX_SG_ELEMENT_LENGTH 0xf000
-#define SBP2_RETRY_LIMIT 0xf /* 15 retries */
+#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(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 @@
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,