[PULL 04/13] hw/sd/sdhci: Stop multiple transfers when block count is cleared

["Philippe Mathieu-Daudé" <f4bug@amsat.org>]

Clearing BlockCount stops multiple transfers.

See "SD Host Controller Simplified Specification Version 2.00":

- 2.2.3. Block Count Register (Offset 006h)
- Table 2-8 : Determination of Transfer Type

Signed-off-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Tested-by: Alexander Bulekov <alxndr@bu.edu>
Message-Id: <20200903172806.489710-2-f4bug@amsat.org>
---
 hw/sd/sdhci.c | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/hw/sd/sdhci.c b/hw/sd/sdhci.c
index c849c3d99b8..61e469bd32f 100644
--- a/hw/sd/sdhci.c
+++ b/hw/sd/sdhci.c
@@ -731,6 +731,12 @@ static void sdhci_do_adma(SDHCIState *s)
     ADMADescr dscr = {};
     int i;
 
+    if (s->trnmod & SDHC_TRNS_BLK_CNT_EN && !s->blkcnt) {
+        /* Stop Multiple Transfer */
+        sdhci_end_transfer(s);
+        return;
+    }
+
     for (i = 0; i < SDHC_ADMA_DESCS_PER_DELAY; ++i) {
         s->admaerr &= ~SDHC_ADMAERR_LENGTH_MISMATCH;
 
@@ -756,7 +762,6 @@ static void sdhci_do_adma(SDHCIState *s)
 
         switch (dscr.attr & SDHC_ADMA_ATTR_ACT_MASK) {
         case SDHC_ADMA_ATTR_ACT_TRAN:  /* data transfer */
-
             if (s->trnmod & SDHC_TRNS_READ) {
                 while (length) {
                     if (s->data_count == 0) {
-- 
2.26.2