Re: [Qemu-devel] [PATCH] Sun4m : SCSI ESP controller

[Olivier Danet <odanet@caramail.com>]

On 20/02/2014 09:58, Mark Cave-Ayland wrote:
> On 16/02/14 23:13, Olivier Danet wrote:
>
>> Two small fixes for the ESP (AM53C94) SCSI controller
>>
>> * Signal the end of the DMA transfer after a SCSI command.
>>
>> * The status register (RSTAT) is cleared after reading the interrupt
>> status register (RINTR), except for the TC bit (=Count To Zero) and the
>> scsi phase bits, which mirror SCSI signals levels.
>>
>> Fixes the bug "esp0: !TC on DATA XFER" with NetBSD
>> https://bugs.launchpad.net/qemu/+bug/1055090
>>
>> Signed-off-by: Olivier Danet <odanet@caramail.com>
>> ---
>> hw/scsi/esp.c | 4 ++--
>> 1 file changed, 2 insertions(+), 2 deletions(-)
>>
>> diff --git a/hw/scsi/esp.c b/hw/scsi/esp.c
>> index 2d150bf..5e91077 100644
>> --- a/hw/scsi/esp.c
>> +++ b/hw/scsi/esp.c
>> @@ -246,6 +246,7 @@ static void esp_do_dma(ESPState *s)
>> s->cmdlen = 0;
>> s->do_cmd = 0;
>> do_cmd(s, s->cmdbuf);
>> + esp_dma_done(s);
>> return;
>> }
>> if (s->async_len == 0) {
>> @@ -417,10 +418,9 @@ uint64_t esp_reg_read(ESPState *s, uint32_t saddr)
>> except TC */
>> old_val = s->rregs[ESP_RINTR];
>> s->rregs[ESP_RINTR] = 0;
>> - s->rregs[ESP_RSTAT] &= ~STAT_TC;
>> s->rregs[ESP_RSEQ] = SEQ_CD;
>> esp_lower_irq(s);
>> -
>> + s->rregs[ESP_RSTAT] &= STAT_TC | STAT_MI;
>> return old_val;
>> default:
>> break;
>
> Hi Olivier,
>
> I've applied the non-whitespace damaged patch (attached) but 
> unfortunately I still see the "!TC on DATA XFER" bug with my NetBSD 5 
> ISO under qemu-system-sparc :/  Note that the second part of the patch 
> showed some fuzz so I'm wondering if this patch is complete or whether 
> part of it is still missing?
>
> Also ESP patches should have an esp or scsi/esp prefix in the subject 
> line and should CC the current SCSI maintainer (see MAINTAINERS file) 
> which is currently Paolo.
>
>
> HTH,
>
> Mark.

I don't get these errors installing NetBSD 5 (tried 5.02 & 5.1).
With NetBSD 6, the patch makes a lot of difference :

http://temlib.org/pub/qemu_tc_patch.png
http://temlib.org/pub/qemu_tc_nopatch.png

(the default terminal during install is terrible)

* The dma() part is a coherence bug in the ESP driver which does not
update the DMA registers after a command transfer.

* The RINTR part makes the driver match more closely the datasheet:
http://sensi.org/download/doc/am53c94.pdf
Page 19/63

These modifications are not particularly tailored for NetBSD nor SPARCs.

Olivier

(Sorry about the whitespaces, I will try to find out the cause !)