From 2b1ecbe87da757ddb12e38239773a05f816d03ae Mon Sep 17 00:00:00 2001
From: cinap_lenrek <cinap_lenrek@felloff.net>
Date: Sat, 18 Jun 2022 20:31:49 +0000
Subject: [PATCH] imx8/usdhc: work around broken multi-write for now

for unknown reasons, multiwrite is busted in usdhc:

sdhc: write error intr 10 stat ff88858e
usdhccmd: need to reset Datinhibit intr 10 stat ff88858e
usdhc: cmd 193a0027 arg 1e5b6b error intr 18010 stat ff88858f

i'm disabling it for now, adding a flag to the SDio struct.
---
 sys/src/9/imx8/usdhc.c | 10 +++++-----
 sys/src/9/port/sd.h    |  1 +
 sys/src/9/port/sdmmc.c |  2 +-
 3 files changed, 7 insertions(+), 6 deletions(-)

diff --git a/sys/src/9/imx8/usdhc.c b/sys/src/9/imx8/usdhc.c
index ba3989211..8954ba8b9 100644
--- a/sys/src/9/imx8/usdhc.c
+++ b/sys/src/9/imx8/usdhc.c
@@ -219,16 +219,15 @@ dmaalloc(void *addr, int len)
 	uintptr a;
 	Adma *adma, *p;
 
-	a = (uintptr)addr;
+	a = PADDR(addr);
 	n = (len + Maxdma-1) / Maxdma;
 	adma = sdmalloc(n * sizeof(Adma));
 	for(p = adma; len > 0; p++){
-		p->desc = Valid | Tran;
 		if(n == 1)
-			p->desc |= len<<OLength | End | Int;
+			p->desc = len<<OLength | End | Int | Valid | Tran;
 		else
-			p->desc |= Maxdma<<OLength;
-		p->addr = PADDR(a);
+			p->desc = Maxdma<<OLength | Valid | Tran;
+		p->addr = a;
 		a += Maxdma;
 		len -= Maxdma;
 		n--;
@@ -529,4 +528,5 @@ SDio sdio = {
 	usdhciosetup,
 	usdhcio,
 	.highspeed = 1,
+	.nomultiwrite = 1,
 };
diff --git a/sys/src/9/port/sd.h b/sys/src/9/port/sd.h
index e4c567a17..0ef5dab33 100644
--- a/sys/src/9/port/sd.h
+++ b/sys/src/9/port/sd.h
@@ -162,6 +162,7 @@ struct SDio {
 	void	(*iosetup)(int, void*, int, int);
 	void	(*io)(int, uchar*, int);
 	char	highspeed;
+	char	nomultiwrite;	/* quirk for usdhc */
 };
 
 extern SDio sdio;
diff --git a/sys/src/9/port/sdmmc.c b/sys/src/9/port/sdmmc.c
index 34dbd046e..d7bd02d97 100644
--- a/sys/src/9/port/sdmmc.c
+++ b/sys/src/9/port/sdmmc.c
@@ -332,7 +332,7 @@ mmcbio(SDunit *unit, int lun, int write, void *data, long nb, uvlong bno)
 		error(Echange);
 	buf = data;
 	len = unit->secsize;
-	if(Multiblock){
+	if(Multiblock && (!write || !io->nomultiwrite)){
 		b = bno;
 		tries = 0;
 		while(waserror())