git: 9front

Info  •  Files  •  Log  •  Branches

audiohda: make it work with qemu (thanks mischief)

the driver was not using irb interrupts
and was just polling the irb write pointer
to wait for command completion.

this is not supported by qemu.

qemu requires the use of irb interrupt handshake
and it refuses to accept the next command until we
acknowledge the irb interrupt.

--- a/sys/src/9/pc/audiohda.c

+++ b/sys/src/9/pc/audiohda.c

@@ -462,10 +462,9 @@

 static int

 hdacmd(Ctlr *ctlr, uint request, uint reply[2])

 {

-	uint rp, wp;

-	uint re;

-	int wait;

-	

+	uint rp, wp, re;

+	int wait, ret;

+

 	re = csr16(ctlr, Rirbwp);

 	rp = csr16(ctlr, Corbrp);

 	wp = (csr16(ctlr, Corbwp) + 1) % ctlr->corbsize;

@@ -476,15 +475,22 @@

 	ctlr->corb[wp] = request;

 	coherence();

 	csr16(ctlr, Corbwp) = wp;

+

+	ret = 0;

 	for(wait=0; wait < Maxrirbwait; wait++){

 		if(csr16(ctlr, Rirbwp) != re){

 			re = (re + 1) % ctlr->rirbsize;

 			memmove(reply, &ctlr->rirb[re*2], 8);

-			return 1;

+			ret = 1;

+			break;

 		}

 		microdelay(1);

 	}

-	return 0;

+

+	/* reset intcnt for qemu */

+	csr8(ctlr, Rirbsts) = Rirbrover|Rirbrint;

+

+	return ret;

 }

 static int

@@ -1732,7 +1738,15 @@

 	csr32(ctlr, Rirblbase) = pa;

 	csr32(ctlr, Rirbubase) = pa >> 32;

 	csr16(ctlr, Rirbwp) = Rirbptrrst;

-	csr8(ctlr, Rirbctl) = Rirbdma;

+

+	/*

+	 * qemu requires interrupt handshake,

+	 * even tho we just poll the irb write

+	 * pointer for command completion.

+	 */

+	csr16(ctlr, Rintcnt) = 1;

+	csr8(ctlr, Rirbctl) = Rirbdma|Rirbint;

+

 	waitup8(ctlr, Rirbctl, Rirbdma, Rirbdma);

 	/* enable interrupts */

-- 

⑨