2  * atari_scsi.c -- Device dependent functions for the Atari generic SCSI port
4  * Copyright 1994 Roman Hodek <Roman.Hodek@informatik.uni-erlangen.de>
7  *    - working real DMA
8  *    - Falcon support (untested yet!)   ++bjoern fixed and now it works
9  *    - lots of extensions and bug fixes.
137  * scatter-gather anyway, so most transfers are 1024 byte only. In the rare
143 /* mask for address bits that can't be used with the ST-DMA */
147 static int setup_can_queue = -1;
149 static int setup_cmd_per_lun = -1;
151 static int setup_sg_tablesize = -1;
153 static int setup_hostid = -1;
155 static int setup_toshiba_delay = -1;
166 		/* A bus error happens when DMA-ing from the last page of a  in scsi_dma_is_ignored_buserr()
199 			printk(KERN_CRIT "SCSI DMA bus error -- bad DMA programming!");  in scsi_tt_intr()
205 	 * This means we have residual bytes, if the desired end address  in scsi_tt_intr()
206 	 * is not yet reached. Maybe we have to fetch some bytes from the  in scsi_tt_intr()
209 	 * addr reg counts bytes not yet written and pending in the rest  in scsi_tt_intr()
213 		atari_dma_residual = hostdata->dma_len -  in scsi_tt_intr()
214 			(SCSI_DMA_READ_P(dma_addr) - atari_dma_startaddr);  in scsi_tt_intr()
216 		dprintk(NDEBUG_DMA, "SCSI DMA: There are %ld residual bytes.\n",  in scsi_tt_intr()
224 			 * transport some rest bytes  in scsi_tt_intr()
229 			 * There seems to be a nasty bug in some SCSI-DMA/NCR  in scsi_tt_intr()
232 			 * DMA may be a few bytes farer than it actually read.  in scsi_tt_intr()
235 			 * dma_addr is 9 bytes to high, but this could vary.  in scsi_tt_intr()
248 					   "difference %ld bytes\n",  in scsi_tt_intr()
249 					   512 - (atari_dma_residual & 0x1ff));  in scsi_tt_intr()
256 	/* If the DMA is finished, fetch the rest bytes and turn it off */  in scsi_tt_intr()
292 	 * calculate the number of residual bytes and give a warning if  in scsi_falcon_intr()
293 	 * bytes are stuck in the ST-DMA fifo (there's no way to reach them!)  in scsi_falcon_intr()
298 		transferred = SCSI_DMA_GETADR() - atari_dma_startaddr;  in scsi_falcon_intr()
299 		/* The ST-DMA address is incremented in 2-byte steps, but the  in scsi_falcon_intr()
300 		 * data are written only in 16-byte chunks. If the number of  in scsi_falcon_intr()
301 		 * transferred bytes is not divisible by 16, the remainder is  in scsi_falcon_intr()
305 			printk(KERN_ERR "SCSI DMA error: %ld bytes lost in "  in scsi_falcon_intr()
306 			       "ST-DMA fifo\n", transferred & 15);  in scsi_falcon_intr()
308 		atari_dma_residual = hostdata->dma_len - transferred;  in scsi_falcon_intr()
309 		dprintk(NDEBUG_DMA, "SCSI DMA: There are %ld residual bytes.\n",  in scsi_falcon_intr()
316 		/* If the dribble buffer was used on a read operation, copy the DMA-ed  in scsi_falcon_intr()
320 		       hostdata->dma_len - atari_dma_residual);  in scsi_falcon_intr()
336 	/* fetch rest bytes in the DMA register */  in atari_scsi_fetch_restbytes()
340 		/* there are 'nr' bytes left for the last long address  in atari_scsi_fetch_restbytes()
343 		dprintk(NDEBUG_DMA, "SCSI DMA: there are %d rest bytes for phys addr 0x%08lx",  in atari_scsi_fetch_restbytes()
348 		for (src = (char *)&tt_scsi_dma.dma_restdata; nr != 0; --nr)  in atari_scsi_fetch_restbytes()
367 /* This function manages the locking of the ST-DMA.
371  * command immediately but tell the SCSI mid-layer to defer.
380 	    instance->hostt->can_queue > 1)  in falcon_get_lock()
432 	        hostdata->host->host_no, data, addr, count, dir);  in atari_scsi_dma_setup()
435 		/* If we have a non-DMAable address on a Falcon, use the dribble  in atari_scsi_dma_setup()
451 	 * the ST-DMA begins to fill internal buffers right after setup. For  in atari_scsi_dma_setup()
476 		/* On writes, round up the transfer length to the next multiple of 512  in atari_scsi_dma_setup()
513 	unsigned char opcode = cmd->cmnd[0];  in falcon_classify_cmd()
521 		/* In case of a sequential-access target (tape), special care is  in falcon_classify_cmd()
522 		 * needed here: The transfer is block-mode only if the 'fixed' bit is  in falcon_classify_cmd()
524 		if (cmd->device->type == TYPE_TAPE && !(cmd->cmnd[1] & 1))  in falcon_classify_cmd()
533 /* This function calculates the number of bytes that can be transferred via
535  * ST-DMA chip. There are only multiples of 512 bytes possible and max.
536  * 255*512 bytes :-( This means also, that defining READ_OVERRUNS is not
538  * n*512 - atari_read_overrun bytes. But it seems that the Falcon doesn't have
539  * the overrun problem, so this question is academic :-)
545 	int wanted_len = cmd->SCp.this_residual;  in atari_scsi_dma_xfer_len()
552 		/* TT SCSI DMA can transfer arbitrary #bytes */  in atari_scsi_dma_xfer_len()
555 	/* ST DMA chip is stupid -- only multiples of 512 bytes! (and max.  in atari_scsi_dma_xfer_len()
556 	 * 255*512 bytes, but this should be enough)  in atari_scsi_dma_xfer_len()
558 	 * ++roman: Aaargl! Another Falcon-SCSI problem... There are some commands  in atari_scsi_dma_xfer_len()
559 	 * that return a number of bytes which cannot be known beforehand. In this  in atari_scsi_dma_xfer_len()
561 	 * can happen that this allocation length is a multiple of 512 bytes and  in atari_scsi_dma_xfer_len()
562 	 * the DMA is used. But if not n*512 bytes really arrive, some input data  in atari_scsi_dma_xfer_len()
563 	 * will be lost in the ST-DMA's FIFO :-( Thus, we have to distinguish  in atari_scsi_dma_xfer_len()
569 	 * The solution: We classify SCSI commands in 1) surely block-mode cmd.s,  in atari_scsi_dma_xfer_len()
570 	 * 2) surely byte-mode cmd.s and 3) cmd.s with unknown mode. In case 1)  in atari_scsi_dma_xfer_len()
577 	 * receiving a sufficient number of bytes.  in atari_scsi_dma_xfer_len()
579 	 * Another point: If the transfer is from/to an non-ST-RAM address, we  in atari_scsi_dma_xfer_len()
580 	 * use the dribble buffer and thus can do only STRAM_BUFFER_SIZE bytes.  in atari_scsi_dma_xfer_len()
583 	if (cmd->sc_data_direction == DMA_TO_DEVICE) {  in atari_scsi_dma_xfer_len()
585 		 * be rounded up to the next multiple of 512 (atari_dma_setup() does  in atari_scsi_dma_xfer_len()
591 		 * 512, we cannot use DMA, since the ST-DMA cannot split transfers  in atari_scsi_dma_xfer_len()
617 	limit = (atari_dma_buffer && !STRAM_ADDR(virt_to_phys(cmd->SCp.ptr))) ?  in atari_scsi_dma_xfer_len()
618 		    STRAM_BUFFER_SIZE : 255*512;  in atari_scsi_dma_xfer_len()
623 		dprintk(NDEBUG_DMA, "DMA transfer now %d bytes instead of %d\n",  in atari_scsi_dma_xfer_len()
717 	.dma_boundary		= PAGE_SIZE - 1,
730 		return -ENODEV;  in atari_scsi_probe()
775 	/* If running on a Falcon and if there's TT-Ram (i.e., more than one  in atari_scsi_probe()
776 	 * memory block, since there's always ST-Ram in a Falcon), then  in atari_scsi_probe()
784 			pr_err(PFX "can't allocate ST-RAM double buffer\n");  in atari_scsi_probe()
785 			return -ENOMEM;  in atari_scsi_probe()
794 		error = -ENOMEM;  in atari_scsi_probe()
798 	instance->irq = irq->start;  in atari_scsi_probe()
808 		error = request_irq(instance->irq, scsi_tt_intr, 0,  in atari_scsi_probe()
812 			       instance->irq);  in atari_scsi_probe()
815 		tt_mfp.active_edge |= 0x80;	/* SCSI int on L->H */  in atari_scsi_probe()
836 			hostdata->read_overruns = 4;  in atari_scsi_probe()
839 		/* Nothing to do for the interrupt: the ST-DMA is initialized  in atari_scsi_probe()
861 		free_irq(instance->irq, instance);  in atari_scsi_probe()
878 		free_irq(instance->irq, instance);  in atari_scsi_remove()