firewire: ohci: do not start DMA contexts before link is enabled
Clemens Ladisch [Mon, 11 Apr 2011 07:56:12 +0000 (09:56 +0200)]
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>

drivers/firewire/ohci.c

index f903d7b..dfb3cb7 100644 (file)
@@ -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);