Le 02/10/2019 à 13:10, Philippe Mathieu-Daudé a écrit :
> On 9/27/19 11:04 AM, Laurent Vivier wrote:
>> There is no DMA in Quadra 800, so the CPU reads/writes the data from the
>> PDMA register (offset 0x100, ESP_PDMA in hw/m68k/q800.c) and copies them
>> to/from the memory.
>>
>> There is a nice assembly loop in the kernel to do that, see
>> linux/drivers/scsi/mac_esp.c:MAC_ESP_PDMA_LOOP().
>>
>> The start of the transfer is triggered by the DREQ interrupt (see linux
>> mac_esp_send_pdma_cmd()), the CPU polls on the IRQ flag to start the
>> transfer after a SCSI command has been sent (in Quadra 800 it goes
>> through the VIA2, the via2-irq line and the vIFR register)
>>
>> The Macintosh hardware includes hardware handshaking to prevent the CPU
>> from reading invalid data or writing data faster than the peripheral
>> device can accept it.
>>
>> This is the "blind mode", and from the doc:
>> "Approximate maximum SCSI transfer rates within a blocks are 1.4 MB per
>> second for blind transfers in the Macintosh II"
>>
>> Some references can be found in:
>> Apple Macintosh Family Hardware Reference, ISBN 0-201-19255-1
>> Guide to the Macintosh Family Hardware, ISBN-0-201-52405-8
>>
>> Acked-by: Dr. David Alan Gilbert <dgilb...@redhat.com>
>> Co-developed-by: Mark Cave-Ayland <mark.cave-ayl...@ilande.co.uk>
>> Signed-off-by: Mark Cave-Ayland <mark.cave-ayl...@ilande.co.uk>
>> Signed-off-by: Laurent Vivier <laur...@vivier.eu>
>> ---
>> hw/scsi/esp.c | 338 ++++++++++++++++++++++++++++++++++++++----
>> include/hw/scsi/esp.h | 15 ++
>
> I recommend you to install the scripts/git.orderfile file.
done
>
>> 2 files changed, 324 insertions(+), 29 deletions(-)
>>
...
>> --- a/include/hw/scsi/esp.h
>> +++ b/include/hw/scsi/esp.h
>> @@ -14,10 +14,18 @@ typedef void (*ESPDMAMemoryReadWriteFunc)(void
>> *opaque, uint8_t *buf, int len);
>> typedef struct ESPState ESPState;
>> +enum pdma_origin_id {
>> + PDMA,
>> + TI,
>> + CMD,
>> + ASYNC,
>> +};
>> +
>> struct ESPState {
>> uint8_t rregs[ESP_REGS];
>> uint8_t wregs[ESP_REGS];
>> qemu_irq irq;
>> + qemu_irq irq_data;
>> uint8_t chip_id;
>> bool tchi_written;
>> int32_t ti_size;
>> @@ -48,6 +56,12 @@ struct ESPState {
>> ESPDMAMemoryReadWriteFunc dma_memory_write;
>> void *dma_opaque;
>> void (*dma_cb)(ESPState *s);
>> + uint8_t pdma_buf[32];
>> + int pdma_origin;
>
> 'int' -> 'enum pdma_origin_id'
>
> You can also declare the enum in place:
>
> enum pdma_origin_id {
> PDMA,
> TI,
> CMD,
> ASYNC,
> } pdma_origin;
If I remember correctly I put an "int" here because I didn't find the
VMSTATE_XXX() to use and VMSTATE_INT32() doesn't like the enum type
(which should be treated as an int).
Thanks,
Laurent
