On 16/02/2021 07:33, Philippe Mathieu-Daudé wrote:
On 2/9/21 8:29 PM, Mark Cave-Ayland wrote:
Perform the length adjustment whereby a value of 0 in the STC represents
a transfer length of 0x10000 at the point where the TC is loaded at the
0x10000 -> 64 KiB?
I'd prefer to keep these as they are, since TC is described in the documentation as
16-bit counter: it is the number of bits that is relevant here as opposed to the
absolute size.
There is a slight bit of trickery here in that the ESP emulation already handles a
later variant of the chip which has a 24-bit counter which is why we can get away
with setting its value to 0x10000 - guests that don't check for this will simply
ignore the register containing the MSB.
start of a DMA command rather than just when a TI (Transfer Information)
command is executed. This better matches the description as given in the
datasheet.
Signed-off-by: Mark Cave-Ayland <mark.cave-ayl...@ilande.co.uk>
---
hw/scsi/esp.c | 9 +++++----
1 file changed, 5 insertions(+), 4 deletions(-)
diff --git a/hw/scsi/esp.c b/hw/scsi/esp.c
index a1acc2c9bd..02b7876394 100644
--- a/hw/scsi/esp.c
+++ b/hw/scsi/esp.c
@@ -562,9 +562,6 @@ static void handle_ti(ESPState *s)
}
dmalen = esp_get_tc(s);
- if (dmalen == 0) {
- dmalen = 0x10000;
- }
s->dma_counter = dmalen;
if (s->do_cmd) {
@@ -699,7 +696,11 @@ void esp_reg_write(ESPState *s, uint32_t saddr, uint64_t
val)
if (val & CMD_DMA) {
s->dma = 1;
/* Reload DMA counter. */
- esp_set_tc(s, esp_get_stc(s));
+ if (esp_get_stc(s) == 0) {
+ esp_set_tc(s, 0x10000);
0x10000 -> 64 * KiB
And same here too.
Reviewed-by: Philippe Mathieu-Daudé <f4...@amsat.org>
ATB,
Mark.