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Merge pull request #2455 from pmackinlay/ncr5390
ncr5390: tcounter and dma/drq changes
This commit is contained in:
R. Belmont
GitHub
commit
9398fff5f6
@ -426,6 +426,10 @@ void ncr5390_device::step(bool timeout)
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dma_set(dma_command ? DMA_OUT : DMA_NONE);
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state = INIT_XFR_SEND_BYTE;
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// can't send if the fifo is empty
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if (fifo_pos == 0)
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break;
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// if it's the last message byte, deassert ATN before sending
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if (xfr_phase == S_PHASE_MSG_OUT && ((!dma_command && fifo_pos == 1) || (dma_command && tcounter == 1)))
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scsi_bus->ctrl_w(scsi_refid, 0, S_ATN);
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@ -438,6 +442,10 @@ void ncr5390_device::step(bool timeout)
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case S_PHASE_MSG_IN:
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dma_set(dma_command ? DMA_IN : DMA_NONE);
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// can't receive if the fifo is full
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if (fifo_pos == 16)
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break;
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// if it's the last message byte, ACK remains asserted, terminate with function_complete()
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state = (xfr_phase == S_PHASE_MSG_IN && (!dma_command || tcounter == 1)) ? INIT_XFR_RECV_BYTE_NACK : INIT_XFR_RECV_BYTE_ACK;
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@ -456,34 +464,55 @@ void ncr5390_device::step(bool timeout)
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break;
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// check for command complete
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if ((dma_command && tcounter == 0 && fifo_pos == 0) // dma in/out: transfer counter == 0 and fifo empty
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if ((dma_command && tcounter == 0) // dma in/out: transfer counter == 0
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|| (!dma_command && (xfr_phase & S_INP) == 0 && fifo_pos == 0) // non-dma out: fifo empty
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|| (!dma_command && (xfr_phase & S_INP) == S_INP && fifo_pos == 1)) // non-dma in: every byte
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bus_complete();
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state = INIT_XFR_BUS_COMPLETE;
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else
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// check for phase change
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if((ctrl & S_PHASE_MASK) != xfr_phase) {
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command_pos = 0;
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bus_complete();
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state = INIT_XFR_BUS_COMPLETE;
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} else {
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state = INIT_XFR;
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step(false);
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}
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step(false);
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break;
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case INIT_XFR_SEND_BYTE:
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decrement_tcounter();
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state = INIT_XFR_WAIT_REQ;
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step(false);
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break;
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case INIT_XFR_RECV_BYTE_ACK:
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decrement_tcounter();
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state = INIT_XFR_WAIT_REQ;
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scsi_bus->ctrl_w(scsi_refid, 0, S_ACK);
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break;
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case INIT_XFR_RECV_BYTE_NACK:
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decrement_tcounter();
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state = INIT_XFR_FUNCTION_COMPLETE;
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step(false);
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break;
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case INIT_XFR_FUNCTION_COMPLETE:
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// wait for the fifo to drain
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if (dma_command && fifo_pos)
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break;
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function_complete();
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break;
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case INIT_XFR_BUS_COMPLETE:
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// wait for the fifo to drain
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if (dma_command && fifo_pos)
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break;
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bus_complete();
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break;
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case INIT_XFR_SEND_PAD_WAIT_REQ:
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if(!(ctrl & S_REQ))
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break;
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@ -498,7 +527,7 @@ void ncr5390_device::step(bool timeout)
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break;
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case INIT_XFR_SEND_PAD:
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tcounter--;
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decrement_tcounter();
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if(tcounter) {
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state = INIT_XFR_SEND_PAD_WAIT_REQ;
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step(false);
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@ -520,7 +549,7 @@ void ncr5390_device::step(bool timeout)
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break;
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case INIT_XFR_RECV_PAD:
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tcounter--;
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decrement_tcounter();
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if(tcounter) {
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state = INIT_XFR_RECV_PAD_WAIT_REQ;
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scsi_bus->ctrl_w(scsi_refid, 0, S_ACK);
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@ -608,7 +637,6 @@ READ8_MEMBER(ncr5390_device::tcounter_lo_r)
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WRITE8_MEMBER(ncr5390_device::tcount_lo_w)
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{
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tcount = (tcount & 0xff00) | data;
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status &= ~S_TC0;
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logerror("%s: tcount_lo_w %02x (%s)\n", tag(), data, machine().describe_context());
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}
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@ -621,7 +649,6 @@ READ8_MEMBER(ncr5390_device::tcounter_hi_r)
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WRITE8_MEMBER(ncr5390_device::tcount_hi_w)
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{
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tcount = (tcount & 0x00ff) | (data << 8);
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status &= ~S_TC0;
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logerror("%s: tcount_hi_w %02x (%s)\n", tag(), data, machine().describe_context());
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}
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@ -630,7 +657,7 @@ uint8_t ncr5390_device::fifo_pop()
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uint8_t r = fifo[0];
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fifo_pos--;
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memmove(fifo, fifo+1, fifo_pos);
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if((!fifo_pos) && tcounter && dma_dir == DMA_OUT)
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if((!fifo_pos) && dma_dir == DMA_OUT)
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drq_set();
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return r;
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}
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@ -703,8 +730,14 @@ void ncr5390_device::start_command()
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// for dma commands, reload transfer counter
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dma_command = command[0] & 0x80;
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if (dma_command)
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{
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tcounter = tcount;
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// clear transfer count zero flag when counter is reloaded
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if (tcounter)
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status &= ~S_TC0;
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}
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switch(c) {
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case CM_NOP:
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command_pop_and_chain();
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@ -823,8 +856,7 @@ READ8_MEMBER(ncr5390_device::status_r)
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uint32_t ctrl = scsi_bus->ctrl_r();
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uint8_t res = status | (ctrl & S_MSG ? 4 : 0) | (ctrl & S_CTL ? 2 : 0) | (ctrl & S_INP ? 1 : 0);
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logerror("%s: status_r %02x (%s)\n", tag(), res, machine().describe_context());
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if(irq)
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status &= ~(S_GROSS_ERROR|S_PARITY|S_TCC);
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return res;
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}
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@ -837,8 +869,13 @@ WRITE8_MEMBER(ncr5390_device::bus_id_w)
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READ8_MEMBER(ncr5390_device::istatus_r)
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{
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uint8_t res = istatus;
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istatus = 0;
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seq = 0;
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if (irq)
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{
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status &= ~(S_GROSS_ERROR | S_PARITY | S_TCC);
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istatus = 0;
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seq = 0;
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}
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check_irq();
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if(res)
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command_pop_and_chain();
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@ -902,16 +939,16 @@ WRITE8_MEMBER(ncr5390_device::clock_w)
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void ncr5390_device::dma_set(int dir)
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{
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dma_dir = dir;
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if(dma_dir == DMA_OUT && fifo_pos != 16 && tcounter != 0)
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if(dma_dir == DMA_OUT && fifo_pos != 16 && tcounter > fifo_pos)
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drq_set();
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}
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void ncr5390_device::dma_w(uint8_t val)
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{
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fifo_push(val);
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tcounter--;
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if(fifo_pos == 16 || tcounter == 0)
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if(fifo_pos == 16)
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drq_clear();
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step(false);
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}
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uint8_t ncr5390_device::dma_r()
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@ -919,11 +956,7 @@ uint8_t ncr5390_device::dma_r()
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uint8_t r = fifo_pop();
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if(!fifo_pos)
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drq_clear();
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tcounter--;
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if(tcounter == 0) {
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status |= S_TC0;
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step(false);
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}
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step(false);
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return r;
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}
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@ -943,6 +976,16 @@ void ncr5390_device::drq_clear()
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}
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}
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void ncr5390_device::decrement_tcounter()
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{
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if (!dma_command)
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return;
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tcounter--;
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if (tcounter == 0)
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status |= S_TC0;
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}
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/*
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* According to the NCR 53C90A, 53C90B data book (http://bitsavers.informatik.uni-stuttgart.de/pdf/ncr/scsi/NCR53C90ab.pdf),
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* the following are the differences from the 53C90:
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@ -112,6 +112,8 @@ protected:
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INIT_XFR_RECV_PAD,
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INIT_XFR_RECV_BYTE_ACK,
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INIT_XFR_RECV_BYTE_NACK,
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INIT_XFR_FUNCTION_COMPLETE,
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INIT_XFR_BUS_COMPLETE,
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INIT_XFR_WAIT_REQ,
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INIT_CPT_RECV_BYTE_ACK,
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INIT_CPT_RECV_WAIT_REQ,
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@ -237,6 +239,8 @@ private:
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void delay(int cycles);
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void delay_cycles(int cycles);
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void decrement_tcounter();
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devcb_write_line m_irq_handler;
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devcb_write_line m_drq_handler;
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};
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@ -129,17 +129,20 @@ void nscsi_harddisk_device::scsi_command()
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logerror("%s: command INQUIRY lun=%d EVPD=%d page=%d alloc=%02x link=%02x\n",
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tag(),
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lun, scsi_cmdbuf[1] & 1, scsi_cmdbuf[2], scsi_cmdbuf[4], scsi_cmdbuf[5]);
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if(lun) {
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bad_lun();
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return;
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}
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int page = scsi_cmdbuf[2];
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int size = scsi_cmdbuf[4];
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switch(page) {
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case 0:
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memset(scsi_cmdbuf, 0, 148);
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scsi_cmdbuf[0] = 0x00; // device is direct-access (e.g. hard disk)
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// From Seagate SCSI Commands Reference Manual (http://www.seagate.com/staticfiles/support/disc/manuals/scsi/100293068a.pdf), page 73:
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// If the SCSI target device is not capable of supporting a peripheral device connected to this logical unit, the
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// device server shall set these fields to 7Fh (i.e., PERIPHERAL QUALIFIER field set to 011b and PERIPHERAL DEVICE
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// TYPE set to 1Fh).
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if (lun != 0)
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scsi_cmdbuf[0] = 0x7f;
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else
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scsi_cmdbuf[0] = 0x00; // device is direct-access (e.g. hard disk)
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scsi_cmdbuf[1] = 0x00; // media is not removable
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scsi_cmdbuf[2] = 0x05; // device complies with SPC-3 standard
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scsi_cmdbuf[3] = 0x01; // response data format = CCS
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