shithub: riscv

Download patch

ref: 02053924100ddb8617f2d3cbd5b3d5e842cef8c3
parent: 950d970671a9432a5525dc3781a9095c04a50331
author: cinap_lenrek <cinap_lenrek@felloff.net>
date: Tue Oct 27 11:16:03 EDT 2020

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 */
--