firewire: ohci: flush AT contexts after bus reset for OHCI 1.2
The OHCI 1.2 (draft) specification, clause 7.2.3.3, allows and
recommends that, after a bus reset, the controller does not flush all
the packets in the AT queues. Therefore, the driver has to do this
itself.
Signed-off-by: Clemens Ladisch <clemens@ladisch.de>
Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
diff --git a/drivers/firewire/ohci.c b/drivers/firewire/ohci.c
index 5e5d5d3..3372cd1 100644
--- a/drivers/firewire/ohci.c
+++ b/drivers/firewire/ohci.c
@@ -125,6 +125,7 @@
struct fw_ohci *ohci;
u32 regs;
int total_allocation;
+ bool flushing;
/*
* List of page-sized buffers for storing DMA descriptors.
@@ -1356,6 +1357,17 @@
return 0;
}
+static void at_context_flush(struct context *ctx)
+{
+ tasklet_disable(&ctx->tasklet);
+
+ ctx->flushing = true;
+ context_tasklet((unsigned long)ctx);
+ ctx->flushing = false;
+
+ tasklet_enable(&ctx->tasklet);
+}
+
static int handle_at_packet(struct context *context,
struct descriptor *d,
struct descriptor *last)
@@ -1365,7 +1377,7 @@
struct fw_ohci *ohci = context->ohci;
int evt;
- if (last->transfer_status == 0)
+ if (last->transfer_status == 0 && !context->flushing)
/* This descriptor isn't done yet, stop iteration. */
return 0;
@@ -1399,11 +1411,15 @@
break;
case OHCI1394_evt_missing_ack:
- /*
- * Using a valid (current) generation count, but the
- * node is not on the bus or not sending acks.
- */
- packet->ack = RCODE_NO_ACK;
+ if (context->flushing)
+ packet->ack = RCODE_GENERATION;
+ else {
+ /*
+ * Using a valid (current) generation count, but the
+ * node is not on the bus or not sending acks.
+ */
+ packet->ack = RCODE_NO_ACK;
+ }
break;
case ACK_COMPLETE + 0x10:
@@ -1416,6 +1432,13 @@
packet->ack = evt - 0x10;
break;
+ case OHCI1394_evt_no_status:
+ if (context->flushing) {
+ packet->ack = RCODE_GENERATION;
+ break;
+ }
+ /* fall through */
+
default:
packet->ack = RCODE_SEND_ERROR;
break;
@@ -1721,9 +1744,18 @@
/* FIXME: Document how the locking works. */
spin_lock_irqsave(&ohci->lock, flags);
- ohci->generation = generation;
+ ohci->generation = -1; /* prevent AT packet queueing */
context_stop(&ohci->at_request_ctx);
context_stop(&ohci->at_response_ctx);
+
+ spin_unlock_irqrestore(&ohci->lock, flags);
+
+ at_context_flush(&ohci->at_request_ctx);
+ at_context_flush(&ohci->at_response_ctx);
+
+ spin_lock_irqsave(&ohci->lock, flags);
+
+ ohci->generation = generation;
reg_write(ohci, OHCI1394_IntEventClear, OHCI1394_busReset);
if (ohci->quirks & QUIRK_RESET_PACKET)