firewire: ohci: do not start DMA contexts before link is enabled

OHCI 1.1 5.7.3 not only forbids enabling or starting any DMA contexts
before the linkEnable bit is set, but also explicitly warns of undefined
behaviour if this order is violated.

Don't violate it then.

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 f903d7b6f34a92bca580b5ed01cf422c9a8caf7c..dfb3cb774a790827d374ebc15ce693a92ed3f1f6 100644 (file)
--- a/drivers/firewire/ohci.c
+++ b/drivers/firewire/ohci.c
@@ -2066,8 +2066,6 @@ static int ohci_enable(struct fw_card *card,
 
        reg_write(ohci, OHCI1394_SelfIDBuffer, ohci->self_id_bus);
        reg_write(ohci, OHCI1394_LinkControlSet,
-                 OHCI1394_LinkControl_rcvSelfID |
-                 OHCI1394_LinkControl_rcvPhyPkt |
                  OHCI1394_LinkControl_cycleTimerEnable |
                  OHCI1394_LinkControl_cycleMaster);
 
@@ -2094,9 +2092,6 @@ static int ohci_enable(struct fw_card *card,
        reg_write(ohci, OHCI1394_FairnessControl, 0);
        card->priority_budget_implemented = ohci->pri_req_max != 0;
 
-       ar_context_run(&ohci->ar_request_ctx);
-       ar_context_run(&ohci->ar_response_ctx);
-
        reg_write(ohci, OHCI1394_PhyUpperBound, 0x00010000);
        reg_write(ohci, OHCI1394_IntEventClear, ~0);
        reg_write(ohci, OHCI1394_IntMaskClear, ~0);
@@ -2186,7 +2181,13 @@ static int ohci_enable(struct fw_card *card,
        reg_write(ohci, OHCI1394_HCControlSet,
                  OHCI1394_HCControl_linkEnable |
                  OHCI1394_HCControl_BIBimageValid);
-       flush_writes(ohci);
+
+       reg_write(ohci, OHCI1394_LinkControlSet,
+                 OHCI1394_LinkControl_rcvSelfID |
+                 OHCI1394_LinkControl_rcvPhyPkt);
+
+       ar_context_run(&ohci->ar_request_ctx);
+       ar_context_run(&ohci->ar_response_ctx); /* also flushes writes */
 
        /* We are ready to go, reset bus to finish initialization. */
        fw_schedule_bus_reset(&ohci->card, false, true);