xref: /openbmc/linux/drivers/scsi/mac53c94.c (revision f220d3eb)
1 /*
2  * SCSI low-level driver for the 53c94 SCSI bus adaptor found
3  * on Power Macintosh computers, controlling the external SCSI chain.
4  * We assume the 53c94 is connected to a DBDMA (descriptor-based DMA)
5  * controller.
6  *
7  * Paul Mackerras, August 1996.
8  * Copyright (C) 1996 Paul Mackerras.
9  */
10 #include <linux/kernel.h>
11 #include <linux/delay.h>
12 #include <linux/types.h>
13 #include <linux/string.h>
14 #include <linux/slab.h>
15 #include <linux/blkdev.h>
16 #include <linux/proc_fs.h>
17 #include <linux/stat.h>
18 #include <linux/spinlock.h>
19 #include <linux/interrupt.h>
20 #include <linux/module.h>
21 #include <linux/pci.h>
22 #include <asm/dbdma.h>
23 #include <asm/io.h>
24 #include <asm/pgtable.h>
25 #include <asm/prom.h>
26 #include <asm/macio.h>
27 
28 #include <scsi/scsi.h>
29 #include <scsi/scsi_cmnd.h>
30 #include <scsi/scsi_device.h>
31 #include <scsi/scsi_host.h>
32 
33 #include "mac53c94.h"
34 
35 enum fsc_phase {
36 	idle,
37 	selecting,
38 	dataing,
39 	completing,
40 	busfreeing,
41 };
42 
43 struct fsc_state {
44 	struct	mac53c94_regs __iomem *regs;
45 	int	intr;
46 	struct	dbdma_regs __iomem *dma;
47 	int	dmaintr;
48 	int	clk_freq;
49 	struct	Scsi_Host *host;
50 	struct scsi_cmnd *request_q;
51 	struct scsi_cmnd *request_qtail;
52 	struct scsi_cmnd *current_req;		/* req we're currently working on */
53 	enum fsc_phase phase;		/* what we're currently trying to do */
54 	struct dbdma_cmd *dma_cmds;	/* space for dbdma commands, aligned */
55 	void	*dma_cmd_space;
56 	struct	pci_dev *pdev;
57 	dma_addr_t dma_addr;
58 	struct macio_dev *mdev;
59 };
60 
61 static void mac53c94_init(struct fsc_state *);
62 static void mac53c94_start(struct fsc_state *);
63 static void mac53c94_interrupt(int, void *);
64 static irqreturn_t do_mac53c94_interrupt(int, void *);
65 static void cmd_done(struct fsc_state *, int result);
66 static void set_dma_cmds(struct fsc_state *, struct scsi_cmnd *);
67 
68 
69 static int mac53c94_queue_lck(struct scsi_cmnd *cmd, void (*done)(struct scsi_cmnd *))
70 {
71 	struct fsc_state *state;
72 
73 #if 0
74 	if (cmd->sc_data_direction == DMA_TO_DEVICE) {
75 		int i;
76 		printk(KERN_DEBUG "mac53c94_queue %p: command is", cmd);
77 		for (i = 0; i < cmd->cmd_len; ++i)
78 			printk(KERN_CONT " %.2x", cmd->cmnd[i]);
79 		printk(KERN_CONT "\n");
80 		printk(KERN_DEBUG "use_sg=%d request_bufflen=%d request_buffer=%p\n",
81 		       scsi_sg_count(cmd), scsi_bufflen(cmd), scsi_sglist(cmd));
82 	}
83 #endif
84 
85 	cmd->scsi_done = done;
86 	cmd->host_scribble = NULL;
87 
88 	state = (struct fsc_state *) cmd->device->host->hostdata;
89 
90 	if (state->request_q == NULL)
91 		state->request_q = cmd;
92 	else
93 		state->request_qtail->host_scribble = (void *) cmd;
94 	state->request_qtail = cmd;
95 
96 	if (state->phase == idle)
97 		mac53c94_start(state);
98 
99 	return 0;
100 }
101 
102 static DEF_SCSI_QCMD(mac53c94_queue)
103 
104 static int mac53c94_host_reset(struct scsi_cmnd *cmd)
105 {
106 	struct fsc_state *state = (struct fsc_state *) cmd->device->host->hostdata;
107 	struct mac53c94_regs __iomem *regs = state->regs;
108 	struct dbdma_regs __iomem *dma = state->dma;
109 	unsigned long flags;
110 
111 	spin_lock_irqsave(cmd->device->host->host_lock, flags);
112 
113 	writel((RUN|PAUSE|FLUSH|WAKE) << 16, &dma->control);
114 	writeb(CMD_SCSI_RESET, &regs->command);	/* assert RST */
115 	udelay(100);			/* leave it on for a while (>= 25us) */
116 	writeb(CMD_RESET, &regs->command);
117 	udelay(20);
118 	mac53c94_init(state);
119 	writeb(CMD_NOP, &regs->command);
120 
121 	spin_unlock_irqrestore(cmd->device->host->host_lock, flags);
122 	return SUCCESS;
123 }
124 
125 static void mac53c94_init(struct fsc_state *state)
126 {
127 	struct mac53c94_regs __iomem *regs = state->regs;
128 	struct dbdma_regs __iomem *dma = state->dma;
129 	int x;
130 
131 	writeb(state->host->this_id | CF1_PAR_ENABLE, &regs->config1);
132 	writeb(TIMO_VAL(250), &regs->sel_timeout);	/* 250ms */
133 	writeb(CLKF_VAL(state->clk_freq), &regs->clk_factor);
134 	writeb(CF2_FEATURE_EN, &regs->config2);
135 	writeb(0, &regs->config3);
136 	writeb(0, &regs->sync_period);
137 	writeb(0, &regs->sync_offset);
138 	x = readb(&regs->interrupt);
139 	writel((RUN|PAUSE|FLUSH|WAKE) << 16, &dma->control);
140 }
141 
142 /*
143  * Start the next command for a 53C94.
144  * Should be called with interrupts disabled.
145  */
146 static void mac53c94_start(struct fsc_state *state)
147 {
148 	struct scsi_cmnd *cmd;
149 	struct mac53c94_regs __iomem *regs = state->regs;
150 	int i;
151 
152 	if (state->phase != idle || state->current_req != NULL)
153 		panic("inappropriate mac53c94_start (state=%p)", state);
154 	if (state->request_q == NULL)
155 		return;
156 	state->current_req = cmd = state->request_q;
157 	state->request_q = (struct scsi_cmnd *) cmd->host_scribble;
158 
159 	/* Off we go */
160 	writeb(0, &regs->count_lo);
161 	writeb(0, &regs->count_mid);
162 	writeb(0, &regs->count_hi);
163 	writeb(CMD_NOP + CMD_DMA_MODE, &regs->command);
164 	udelay(1);
165 	writeb(CMD_FLUSH, &regs->command);
166 	udelay(1);
167 	writeb(cmd->device->id, &regs->dest_id);
168 	writeb(0, &regs->sync_period);
169 	writeb(0, &regs->sync_offset);
170 
171 	/* load the command into the FIFO */
172 	for (i = 0; i < cmd->cmd_len; ++i)
173 		writeb(cmd->cmnd[i], &regs->fifo);
174 
175 	/* do select without ATN XXX */
176 	writeb(CMD_SELECT, &regs->command);
177 	state->phase = selecting;
178 
179 	set_dma_cmds(state, cmd);
180 }
181 
182 static irqreturn_t do_mac53c94_interrupt(int irq, void *dev_id)
183 {
184 	unsigned long flags;
185 	struct Scsi_Host *dev = ((struct fsc_state *) dev_id)->current_req->device->host;
186 
187 	spin_lock_irqsave(dev->host_lock, flags);
188 	mac53c94_interrupt(irq, dev_id);
189 	spin_unlock_irqrestore(dev->host_lock, flags);
190 	return IRQ_HANDLED;
191 }
192 
193 static void mac53c94_interrupt(int irq, void *dev_id)
194 {
195 	struct fsc_state *state = (struct fsc_state *) dev_id;
196 	struct mac53c94_regs __iomem *regs = state->regs;
197 	struct dbdma_regs __iomem *dma = state->dma;
198 	struct scsi_cmnd *cmd = state->current_req;
199 	int nb, stat, seq, intr;
200 	static int mac53c94_errors;
201 
202 	/*
203 	 * Apparently, reading the interrupt register unlatches
204 	 * the status and sequence step registers.
205 	 */
206 	seq = readb(&regs->seqstep);
207 	stat = readb(&regs->status);
208 	intr = readb(&regs->interrupt);
209 
210 #if 0
211 	printk(KERN_DEBUG "mac53c94_intr, intr=%x stat=%x seq=%x phase=%d\n",
212 	       intr, stat, seq, state->phase);
213 #endif
214 
215 	if (intr & INTR_RESET) {
216 		/* SCSI bus was reset */
217 		printk(KERN_INFO "external SCSI bus reset detected\n");
218 		writeb(CMD_NOP, &regs->command);
219 		writel(RUN << 16, &dma->control);	/* stop dma */
220 		cmd_done(state, DID_RESET << 16);
221 		return;
222 	}
223 	if (intr & INTR_ILL_CMD) {
224 		printk(KERN_ERR "53c94: invalid cmd, intr=%x stat=%x seq=%x phase=%d\n",
225 		       intr, stat, seq, state->phase);
226 		cmd_done(state, DID_ERROR << 16);
227 		return;
228 	}
229 	if (stat & STAT_ERROR) {
230 #if 0
231 		/* XXX these seem to be harmless? */
232 		printk("53c94: bad error, intr=%x stat=%x seq=%x phase=%d\n",
233 		       intr, stat, seq, state->phase);
234 #endif
235 		++mac53c94_errors;
236 		writeb(CMD_NOP + CMD_DMA_MODE, &regs->command);
237 	}
238 	if (cmd == 0) {
239 		printk(KERN_DEBUG "53c94: interrupt with no command active?\n");
240 		return;
241 	}
242 	if (stat & STAT_PARITY) {
243 		printk(KERN_ERR "mac53c94: parity error\n");
244 		cmd_done(state, DID_PARITY << 16);
245 		return;
246 	}
247 	switch (state->phase) {
248 	case selecting:
249 		if (intr & INTR_DISCONNECT) {
250 			/* selection timed out */
251 			cmd_done(state, DID_BAD_TARGET << 16);
252 			return;
253 		}
254 		if (intr != INTR_BUS_SERV + INTR_DONE) {
255 			printk(KERN_DEBUG "got intr %x during selection\n", intr);
256 			cmd_done(state, DID_ERROR << 16);
257 			return;
258 		}
259 		if ((seq & SS_MASK) != SS_DONE) {
260 			printk(KERN_DEBUG "seq step %x after command\n", seq);
261 			cmd_done(state, DID_ERROR << 16);
262 			return;
263 		}
264 		writeb(CMD_NOP, &regs->command);
265 		/* set DMA controller going if any data to transfer */
266 		if ((stat & (STAT_MSG|STAT_CD)) == 0
267 		    && (scsi_sg_count(cmd) > 0 || scsi_bufflen(cmd))) {
268 			nb = cmd->SCp.this_residual;
269 			if (nb > 0xfff0)
270 				nb = 0xfff0;
271 			cmd->SCp.this_residual -= nb;
272 			writeb(nb, &regs->count_lo);
273 			writeb(nb >> 8, &regs->count_mid);
274 			writeb(CMD_DMA_MODE + CMD_NOP, &regs->command);
275 			writel(virt_to_phys(state->dma_cmds), &dma->cmdptr);
276 			writel((RUN << 16) | RUN, &dma->control);
277 			writeb(CMD_DMA_MODE + CMD_XFER_DATA, &regs->command);
278 			state->phase = dataing;
279 			break;
280 		} else if ((stat & STAT_PHASE) == STAT_CD + STAT_IO) {
281 			/* up to status phase already */
282 			writeb(CMD_I_COMPLETE, &regs->command);
283 			state->phase = completing;
284 		} else {
285 			printk(KERN_DEBUG "in unexpected phase %x after cmd\n",
286 			       stat & STAT_PHASE);
287 			cmd_done(state, DID_ERROR << 16);
288 			return;
289 		}
290 		break;
291 
292 	case dataing:
293 		if (intr != INTR_BUS_SERV) {
294 			printk(KERN_DEBUG "got intr %x before status\n", intr);
295 			cmd_done(state, DID_ERROR << 16);
296 			return;
297 		}
298 		if (cmd->SCp.this_residual != 0
299 		    && (stat & (STAT_MSG|STAT_CD)) == 0) {
300 			/* Set up the count regs to transfer more */
301 			nb = cmd->SCp.this_residual;
302 			if (nb > 0xfff0)
303 				nb = 0xfff0;
304 			cmd->SCp.this_residual -= nb;
305 			writeb(nb, &regs->count_lo);
306 			writeb(nb >> 8, &regs->count_mid);
307 			writeb(CMD_DMA_MODE + CMD_NOP, &regs->command);
308 			writeb(CMD_DMA_MODE + CMD_XFER_DATA, &regs->command);
309 			break;
310 		}
311 		if ((stat & STAT_PHASE) != STAT_CD + STAT_IO) {
312 			printk(KERN_DEBUG "intr %x before data xfer complete\n", intr);
313 		}
314 		writel(RUN << 16, &dma->control);	/* stop dma */
315 		scsi_dma_unmap(cmd);
316 		/* should check dma status */
317 		writeb(CMD_I_COMPLETE, &regs->command);
318 		state->phase = completing;
319 		break;
320 	case completing:
321 		if (intr != INTR_DONE) {
322 			printk(KERN_DEBUG "got intr %x on completion\n", intr);
323 			cmd_done(state, DID_ERROR << 16);
324 			return;
325 		}
326 		cmd->SCp.Status = readb(&regs->fifo);
327 		cmd->SCp.Message = readb(&regs->fifo);
328 		cmd->result = CMD_ACCEPT_MSG;
329 		writeb(CMD_ACCEPT_MSG, &regs->command);
330 		state->phase = busfreeing;
331 		break;
332 	case busfreeing:
333 		if (intr != INTR_DISCONNECT) {
334 			printk(KERN_DEBUG "got intr %x when expected disconnect\n", intr);
335 		}
336 		cmd_done(state, (DID_OK << 16) + (cmd->SCp.Message << 8)
337 			 + cmd->SCp.Status);
338 		break;
339 	default:
340 		printk(KERN_DEBUG "don't know about phase %d\n", state->phase);
341 	}
342 }
343 
344 static void cmd_done(struct fsc_state *state, int result)
345 {
346 	struct scsi_cmnd *cmd;
347 
348 	cmd = state->current_req;
349 	if (cmd != 0) {
350 		cmd->result = result;
351 		(*cmd->scsi_done)(cmd);
352 		state->current_req = NULL;
353 	}
354 	state->phase = idle;
355 	mac53c94_start(state);
356 }
357 
358 /*
359  * Set up DMA commands for transferring data.
360  */
361 static void set_dma_cmds(struct fsc_state *state, struct scsi_cmnd *cmd)
362 {
363 	int i, dma_cmd, total, nseg;
364 	struct scatterlist *scl;
365 	struct dbdma_cmd *dcmds;
366 	dma_addr_t dma_addr;
367 	u32 dma_len;
368 
369 	nseg = scsi_dma_map(cmd);
370 	BUG_ON(nseg < 0);
371 	if (!nseg)
372 		return;
373 
374 	dma_cmd = cmd->sc_data_direction == DMA_TO_DEVICE ?
375 			OUTPUT_MORE : INPUT_MORE;
376 	dcmds = state->dma_cmds;
377 	total = 0;
378 
379 	scsi_for_each_sg(cmd, scl, nseg, i) {
380 		dma_addr = sg_dma_address(scl);
381 		dma_len = sg_dma_len(scl);
382 		if (dma_len > 0xffff)
383 			panic("mac53c94: scatterlist element >= 64k");
384 		total += dma_len;
385 		dcmds->req_count = cpu_to_le16(dma_len);
386 		dcmds->command = cpu_to_le16(dma_cmd);
387 		dcmds->phy_addr = cpu_to_le32(dma_addr);
388 		dcmds->xfer_status = 0;
389 		++dcmds;
390 	}
391 
392 	dma_cmd += OUTPUT_LAST - OUTPUT_MORE;
393 	dcmds[-1].command = cpu_to_le16(dma_cmd);
394 	dcmds->command = cpu_to_le16(DBDMA_STOP);
395 	cmd->SCp.this_residual = total;
396 }
397 
398 static struct scsi_host_template mac53c94_template = {
399 	.proc_name	= "53c94",
400 	.name		= "53C94",
401 	.queuecommand	= mac53c94_queue,
402 	.eh_host_reset_handler = mac53c94_host_reset,
403 	.can_queue	= 1,
404 	.this_id	= 7,
405 	.sg_tablesize	= SG_ALL,
406 	.use_clustering	= DISABLE_CLUSTERING,
407 };
408 
409 static int mac53c94_probe(struct macio_dev *mdev, const struct of_device_id *match)
410 {
411 	struct device_node *node = macio_get_of_node(mdev);
412 	struct pci_dev *pdev = macio_get_pci_dev(mdev);
413 	struct fsc_state *state;
414 	struct Scsi_Host *host;
415 	void *dma_cmd_space;
416 	const unsigned char *clkprop;
417 	int proplen, rc = -ENODEV;
418 
419 	if (macio_resource_count(mdev) != 2 || macio_irq_count(mdev) != 2) {
420 		printk(KERN_ERR "mac53c94: expected 2 addrs and intrs"
421 		       " (got %d/%d)\n",
422 		       macio_resource_count(mdev), macio_irq_count(mdev));
423 		return -ENODEV;
424 	}
425 
426 	if (macio_request_resources(mdev, "mac53c94") != 0) {
427        		printk(KERN_ERR "mac53c94: unable to request memory resources");
428 		return -EBUSY;
429 	}
430 
431        	host = scsi_host_alloc(&mac53c94_template, sizeof(struct fsc_state));
432 	if (host == NULL) {
433 		printk(KERN_ERR "mac53c94: couldn't register host");
434 		rc = -ENOMEM;
435 		goto out_release;
436 	}
437 
438 	state = (struct fsc_state *) host->hostdata;
439 	macio_set_drvdata(mdev, state);
440 	state->host = host;
441 	state->pdev = pdev;
442 	state->mdev = mdev;
443 
444 	state->regs = (struct mac53c94_regs __iomem *)
445 		ioremap(macio_resource_start(mdev, 0), 0x1000);
446 	state->intr = macio_irq(mdev, 0);
447 	state->dma = (struct dbdma_regs __iomem *)
448 		ioremap(macio_resource_start(mdev, 1), 0x1000);
449 	state->dmaintr = macio_irq(mdev, 1);
450 	if (state->regs == NULL || state->dma == NULL) {
451 		printk(KERN_ERR "mac53c94: ioremap failed for %pOF\n", node);
452 		goto out_free;
453 	}
454 
455 	clkprop = of_get_property(node, "clock-frequency", &proplen);
456        	if (clkprop == NULL || proplen != sizeof(int)) {
457        		printk(KERN_ERR "%pOF: can't get clock frequency, "
458        		       "assuming 25MHz\n", node);
459        		state->clk_freq = 25000000;
460        	} else
461        		state->clk_freq = *(int *)clkprop;
462 
463        	/* Space for dma command list: +1 for stop command,
464        	 * +1 to allow for aligning.
465 	 * XXX FIXME: Use DMA consistent routines
466 	 */
467        	dma_cmd_space = kmalloc_array(host->sg_tablesize + 2,
468 					     sizeof(struct dbdma_cmd),
469 					     GFP_KERNEL);
470        	if (dma_cmd_space == 0) {
471        		printk(KERN_ERR "mac53c94: couldn't allocate dma "
472        		       "command space for %pOF\n", node);
473 		rc = -ENOMEM;
474        		goto out_free;
475        	}
476 	state->dma_cmds = (struct dbdma_cmd *)DBDMA_ALIGN(dma_cmd_space);
477 	memset(state->dma_cmds, 0, (host->sg_tablesize + 1)
478 	       * sizeof(struct dbdma_cmd));
479 	state->dma_cmd_space = dma_cmd_space;
480 
481 	mac53c94_init(state);
482 
483 	if (request_irq(state->intr, do_mac53c94_interrupt, 0, "53C94",state)) {
484 		printk(KERN_ERR "mac53C94: can't get irq %d for %pOF\n",
485 		       state->intr, node);
486 		goto out_free_dma;
487 	}
488 
489 	rc = scsi_add_host(host, &mdev->ofdev.dev);
490 	if (rc != 0)
491 		goto out_release_irq;
492 
493 	scsi_scan_host(host);
494 	return 0;
495 
496  out_release_irq:
497 	free_irq(state->intr, state);
498  out_free_dma:
499 	kfree(state->dma_cmd_space);
500  out_free:
501 	if (state->dma != NULL)
502 		iounmap(state->dma);
503 	if (state->regs != NULL)
504 		iounmap(state->regs);
505 	scsi_host_put(host);
506  out_release:
507 	macio_release_resources(mdev);
508 
509 	return rc;
510 }
511 
512 static int mac53c94_remove(struct macio_dev *mdev)
513 {
514 	struct fsc_state *fp = (struct fsc_state *)macio_get_drvdata(mdev);
515 	struct Scsi_Host *host = fp->host;
516 
517 	scsi_remove_host(host);
518 
519 	free_irq(fp->intr, fp);
520 
521 	if (fp->regs)
522 		iounmap(fp->regs);
523 	if (fp->dma)
524 		iounmap(fp->dma);
525 	kfree(fp->dma_cmd_space);
526 
527 	scsi_host_put(host);
528 
529 	macio_release_resources(mdev);
530 
531 	return 0;
532 }
533 
534 
535 static struct of_device_id mac53c94_match[] =
536 {
537 	{
538 	.name 		= "53c94",
539 	},
540 	{},
541 };
542 MODULE_DEVICE_TABLE (of, mac53c94_match);
543 
544 static struct macio_driver mac53c94_driver =
545 {
546 	.driver = {
547 		.name 		= "mac53c94",
548 		.owner		= THIS_MODULE,
549 		.of_match_table	= mac53c94_match,
550 	},
551 	.probe		= mac53c94_probe,
552 	.remove		= mac53c94_remove,
553 };
554 
555 
556 static int __init init_mac53c94(void)
557 {
558 	return macio_register_driver(&mac53c94_driver);
559 }
560 
561 static void __exit exit_mac53c94(void)
562 {
563 	return macio_unregister_driver(&mac53c94_driver);
564 }
565 
566 module_init(init_mac53c94);
567 module_exit(exit_mac53c94);
568 
569 MODULE_DESCRIPTION("PowerMac 53c94 SCSI driver");
570 MODULE_AUTHOR("Paul Mackerras <paulus@samba.org>");
571 MODULE_LICENSE("GPL");
572