xref: /openbmc/linux/drivers/ata/pata_ep93xx.c (revision 9aa2cba7)
1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * EP93XX PATA controller driver.
4  *
5  * Copyright (c) 2012, Metasoft s.c.
6  *	Rafal Prylowski <prylowski@metasoft.pl>
7  *
8  * Based on pata_scc.c, pata_icside.c and on earlier version of EP93XX
9  * PATA driver by Lennert Buytenhek and Alessandro Zummo.
10  * Read/Write timings, resource management and other improvements
11  * from driver by Joao Ramos and Bartlomiej Zolnierkiewicz.
12  * DMA engine support based on spi-ep93xx.c by Mika Westerberg.
13  *
14  * Original copyrights:
15  *
16  * Support for Cirrus Logic's EP93xx (EP9312, EP9315) CPUs
17  * PATA host controller driver.
18  *
19  * Copyright (c) 2009, Bartlomiej Zolnierkiewicz
20  *
21  * Heavily based on the ep93xx-ide.c driver:
22  *
23  * Copyright (c) 2009, Joao Ramos <joao.ramos@inov.pt>
24  *		      INESC Inovacao (INOV)
25  *
26  * EP93XX PATA controller driver.
27  * Copyright (C) 2007 Lennert Buytenhek <buytenh@wantstofly.org>
28  *
29  * An ATA driver for the Cirrus Logic EP93xx PATA controller.
30  *
31  * Based on an earlier version by Alessandro Zummo, which is:
32  *   Copyright (C) 2006 Tower Technologies
33  */
34 
35 #include <linux/err.h>
36 #include <linux/kernel.h>
37 #include <linux/module.h>
38 #include <linux/blkdev.h>
39 #include <scsi/scsi_host.h>
40 #include <linux/ata.h>
41 #include <linux/libata.h>
42 #include <linux/platform_device.h>
43 #include <linux/sys_soc.h>
44 #include <linux/delay.h>
45 #include <linux/dmaengine.h>
46 #include <linux/ktime.h>
47 
48 #include <linux/platform_data/dma-ep93xx.h>
49 #include <linux/soc/cirrus/ep93xx.h>
50 
51 #define DRV_NAME	"ep93xx-ide"
52 #define DRV_VERSION	"1.0"
53 
54 enum {
55 	/* IDE Control Register */
56 	IDECTRL				= 0x00,
57 	IDECTRL_CS0N			= (1 << 0),
58 	IDECTRL_CS1N			= (1 << 1),
59 	IDECTRL_DIORN			= (1 << 5),
60 	IDECTRL_DIOWN			= (1 << 6),
61 	IDECTRL_INTRQ			= (1 << 9),
62 	IDECTRL_IORDY			= (1 << 10),
63 	/*
64 	 * the device IDE register to be accessed is selected through
65 	 * IDECTRL register's specific bitfields 'DA', 'CS1N' and 'CS0N':
66 	 *   b4   b3   b2    b1     b0
67 	 *   A2   A1   A0   CS1N   CS0N
68 	 * the values filled in this structure allows the value to be directly
69 	 * ORed to the IDECTRL register, hence giving directly the A[2:0] and
70 	 * CS1N/CS0N values for each IDE register.
71 	 * The values correspond to the transformation:
72 	 *   ((real IDE address) << 2) | CS1N value << 1 | CS0N value
73 	 */
74 	IDECTRL_ADDR_CMD		= 0 + 2, /* CS1 */
75 	IDECTRL_ADDR_DATA		= (ATA_REG_DATA << 2) + 2,
76 	IDECTRL_ADDR_ERROR		= (ATA_REG_ERR << 2) + 2,
77 	IDECTRL_ADDR_FEATURE		= (ATA_REG_FEATURE << 2) + 2,
78 	IDECTRL_ADDR_NSECT		= (ATA_REG_NSECT << 2) + 2,
79 	IDECTRL_ADDR_LBAL		= (ATA_REG_LBAL << 2) + 2,
80 	IDECTRL_ADDR_LBAM		= (ATA_REG_LBAM << 2) + 2,
81 	IDECTRL_ADDR_LBAH		= (ATA_REG_LBAH << 2) + 2,
82 	IDECTRL_ADDR_DEVICE		= (ATA_REG_DEVICE << 2) + 2,
83 	IDECTRL_ADDR_STATUS		= (ATA_REG_STATUS << 2) + 2,
84 	IDECTRL_ADDR_COMMAND		= (ATA_REG_CMD << 2) + 2,
85 	IDECTRL_ADDR_ALTSTATUS		= (0x06 << 2) + 1, /* CS0 */
86 	IDECTRL_ADDR_CTL		= (0x06 << 2) + 1, /* CS0 */
87 
88 	/* IDE Configuration Register */
89 	IDECFG				= 0x04,
90 	IDECFG_IDEEN			= (1 << 0),
91 	IDECFG_PIO			= (1 << 1),
92 	IDECFG_MDMA			= (1 << 2),
93 	IDECFG_UDMA			= (1 << 3),
94 	IDECFG_MODE_SHIFT		= 4,
95 	IDECFG_MODE_MASK		= (0xf << 4),
96 	IDECFG_WST_SHIFT		= 8,
97 	IDECFG_WST_MASK			= (0x3 << 8),
98 
99 	/* MDMA Operation Register */
100 	IDEMDMAOP			= 0x08,
101 
102 	/* UDMA Operation Register */
103 	IDEUDMAOP			= 0x0c,
104 	IDEUDMAOP_UEN			= (1 << 0),
105 	IDEUDMAOP_RWOP			= (1 << 1),
106 
107 	/* PIO/MDMA/UDMA Data Registers */
108 	IDEDATAOUT			= 0x10,
109 	IDEDATAIN			= 0x14,
110 	IDEMDMADATAOUT			= 0x18,
111 	IDEMDMADATAIN			= 0x1c,
112 	IDEUDMADATAOUT			= 0x20,
113 	IDEUDMADATAIN			= 0x24,
114 
115 	/* UDMA Status Register */
116 	IDEUDMASTS			= 0x28,
117 	IDEUDMASTS_DMAIDE		= (1 << 16),
118 	IDEUDMASTS_INTIDE		= (1 << 17),
119 	IDEUDMASTS_SBUSY		= (1 << 18),
120 	IDEUDMASTS_NDO			= (1 << 24),
121 	IDEUDMASTS_NDI			= (1 << 25),
122 	IDEUDMASTS_N4X			= (1 << 26),
123 
124 	/* UDMA Debug Status Register */
125 	IDEUDMADEBUG			= 0x2c,
126 };
127 
128 struct ep93xx_pata_data {
129 	const struct platform_device *pdev;
130 	void __iomem *ide_base;
131 	struct ata_timing t;
132 	bool iordy;
133 
134 	unsigned long udma_in_phys;
135 	unsigned long udma_out_phys;
136 
137 	struct dma_chan *dma_rx_channel;
138 	struct ep93xx_dma_data dma_rx_data;
139 	struct dma_chan *dma_tx_channel;
140 	struct ep93xx_dma_data dma_tx_data;
141 };
142 
143 static void ep93xx_pata_clear_regs(void __iomem *base)
144 {
145 	writel(IDECTRL_CS0N | IDECTRL_CS1N | IDECTRL_DIORN |
146 		IDECTRL_DIOWN, base + IDECTRL);
147 
148 	writel(0, base + IDECFG);
149 	writel(0, base + IDEMDMAOP);
150 	writel(0, base + IDEUDMAOP);
151 	writel(0, base + IDEDATAOUT);
152 	writel(0, base + IDEDATAIN);
153 	writel(0, base + IDEMDMADATAOUT);
154 	writel(0, base + IDEMDMADATAIN);
155 	writel(0, base + IDEUDMADATAOUT);
156 	writel(0, base + IDEUDMADATAIN);
157 	writel(0, base + IDEUDMADEBUG);
158 }
159 
160 static bool ep93xx_pata_check_iordy(void __iomem *base)
161 {
162 	return !!(readl(base + IDECTRL) & IDECTRL_IORDY);
163 }
164 
165 /*
166  * According to EP93xx User's Guide, WST field of IDECFG specifies number
167  * of HCLK cycles to hold the data bus after a PIO write operation.
168  * It should be programmed to guarantee following delays:
169  *
170  * PIO Mode   [ns]
171  * 0          30
172  * 1          20
173  * 2          15
174  * 3          10
175  * 4          5
176  *
177  * Maximum possible value for HCLK is 100MHz.
178  */
179 static int ep93xx_pata_get_wst(int pio_mode)
180 {
181 	int val;
182 
183 	if (pio_mode == 0)
184 		val = 3;
185 	else if (pio_mode < 3)
186 		val = 2;
187 	else
188 		val = 1;
189 
190 	return val << IDECFG_WST_SHIFT;
191 }
192 
193 static void ep93xx_pata_enable_pio(void __iomem *base, int pio_mode)
194 {
195 	writel(IDECFG_IDEEN | IDECFG_PIO |
196 		ep93xx_pata_get_wst(pio_mode) |
197 		(pio_mode << IDECFG_MODE_SHIFT), base + IDECFG);
198 }
199 
200 /*
201  * Based on delay loop found in mach-pxa/mp900.c.
202  *
203  * Single iteration should take 5 cpu cycles. This is 25ns assuming the
204  * fastest ep93xx cpu speed (200MHz) and is better optimized for PIO4 timings
205  * than eg. 20ns.
206  */
207 static void ep93xx_pata_delay(unsigned long count)
208 {
209 	__asm__ volatile (
210 		"0:\n"
211 		"mov r0, r0\n"
212 		"subs %0, %1, #1\n"
213 		"bge 0b\n"
214 		: "=r" (count)
215 		: "0" (count)
216 	);
217 }
218 
219 static unsigned long ep93xx_pata_wait_for_iordy(void __iomem *base,
220 						unsigned long t2)
221 {
222 	/*
223 	 * According to ATA specification, IORDY pin can be first sampled
224 	 * tA = 35ns after activation of DIOR-/DIOW-. Maximum IORDY pulse
225 	 * width is tB = 1250ns.
226 	 *
227 	 * We are already t2 delay loop iterations after activation of
228 	 * DIOR-/DIOW-, so we set timeout to (1250 + 35) / 25 - t2 additional
229 	 * delay loop iterations.
230 	 */
231 	unsigned long start = (1250 + 35) / 25 - t2;
232 	unsigned long counter = start;
233 
234 	while (!ep93xx_pata_check_iordy(base) && counter--)
235 		ep93xx_pata_delay(1);
236 	return start - counter;
237 }
238 
239 /* common part at start of ep93xx_pata_read/write() */
240 static void ep93xx_pata_rw_begin(void __iomem *base, unsigned long addr,
241 				 unsigned long t1)
242 {
243 	writel(IDECTRL_DIOWN | IDECTRL_DIORN | addr, base + IDECTRL);
244 	ep93xx_pata_delay(t1);
245 }
246 
247 /* common part at end of ep93xx_pata_read/write() */
248 static void ep93xx_pata_rw_end(void __iomem *base, unsigned long addr,
249 			       bool iordy, unsigned long t0, unsigned long t2,
250 			       unsigned long t2i)
251 {
252 	ep93xx_pata_delay(t2);
253 	/* lengthen t2 if needed */
254 	if (iordy)
255 		t2 += ep93xx_pata_wait_for_iordy(base, t2);
256 	writel(IDECTRL_DIOWN | IDECTRL_DIORN | addr, base + IDECTRL);
257 	if (t0 > t2 && t0 - t2 > t2i)
258 		ep93xx_pata_delay(t0 - t2);
259 	else
260 		ep93xx_pata_delay(t2i);
261 }
262 
263 static u16 ep93xx_pata_read(struct ep93xx_pata_data *drv_data,
264 			    unsigned long addr,
265 			    bool reg)
266 {
267 	void __iomem *base = drv_data->ide_base;
268 	const struct ata_timing *t = &drv_data->t;
269 	unsigned long t0 = reg ? t->cyc8b : t->cycle;
270 	unsigned long t2 = reg ? t->act8b : t->active;
271 	unsigned long t2i = reg ? t->rec8b : t->recover;
272 
273 	ep93xx_pata_rw_begin(base, addr, t->setup);
274 	writel(IDECTRL_DIOWN | addr, base + IDECTRL);
275 	/*
276 	 * The IDEDATAIN register is loaded from the DD pins at the positive
277 	 * edge of the DIORN signal. (EP93xx UG p27-14)
278 	 */
279 	ep93xx_pata_rw_end(base, addr, drv_data->iordy, t0, t2, t2i);
280 	return readl(base + IDEDATAIN);
281 }
282 
283 /* IDE register read */
284 static u16 ep93xx_pata_read_reg(struct ep93xx_pata_data *drv_data,
285 				unsigned long addr)
286 {
287 	return ep93xx_pata_read(drv_data, addr, true);
288 }
289 
290 /* PIO data read */
291 static u16 ep93xx_pata_read_data(struct ep93xx_pata_data *drv_data,
292 				 unsigned long addr)
293 {
294 	return ep93xx_pata_read(drv_data, addr, false);
295 }
296 
297 static void ep93xx_pata_write(struct ep93xx_pata_data *drv_data,
298 			      u16 value, unsigned long addr,
299 			      bool reg)
300 {
301 	void __iomem *base = drv_data->ide_base;
302 	const struct ata_timing *t = &drv_data->t;
303 	unsigned long t0 = reg ? t->cyc8b : t->cycle;
304 	unsigned long t2 = reg ? t->act8b : t->active;
305 	unsigned long t2i = reg ? t->rec8b : t->recover;
306 
307 	ep93xx_pata_rw_begin(base, addr, t->setup);
308 	/*
309 	 * Value from IDEDATAOUT register is driven onto the DD pins when
310 	 * DIOWN is low. (EP93xx UG p27-13)
311 	 */
312 	writel(value, base + IDEDATAOUT);
313 	writel(IDECTRL_DIORN | addr, base + IDECTRL);
314 	ep93xx_pata_rw_end(base, addr, drv_data->iordy, t0, t2, t2i);
315 }
316 
317 /* IDE register write */
318 static void ep93xx_pata_write_reg(struct ep93xx_pata_data *drv_data,
319 				  u16 value, unsigned long addr)
320 {
321 	ep93xx_pata_write(drv_data, value, addr, true);
322 }
323 
324 /* PIO data write */
325 static void ep93xx_pata_write_data(struct ep93xx_pata_data *drv_data,
326 				   u16 value, unsigned long addr)
327 {
328 	ep93xx_pata_write(drv_data, value, addr, false);
329 }
330 
331 static void ep93xx_pata_set_piomode(struct ata_port *ap,
332 				    struct ata_device *adev)
333 {
334 	struct ep93xx_pata_data *drv_data = ap->host->private_data;
335 	struct ata_device *pair = ata_dev_pair(adev);
336 	/*
337 	 * Calculate timings for the delay loop, assuming ep93xx cpu speed
338 	 * is 200MHz (maximum possible for ep93xx). If actual cpu speed is
339 	 * slower, we will wait a bit longer in each delay.
340 	 * Additional division of cpu speed by 5, because single iteration
341 	 * of our delay loop takes 5 cpu cycles (25ns).
342 	 */
343 	unsigned long T = 1000000 / (200 / 5);
344 
345 	ata_timing_compute(adev, adev->pio_mode, &drv_data->t, T, 0);
346 	if (pair && pair->pio_mode) {
347 		struct ata_timing t;
348 		ata_timing_compute(pair, pair->pio_mode, &t, T, 0);
349 		ata_timing_merge(&t, &drv_data->t, &drv_data->t,
350 			ATA_TIMING_SETUP | ATA_TIMING_8BIT);
351 	}
352 	drv_data->iordy = ata_pio_need_iordy(adev);
353 
354 	ep93xx_pata_enable_pio(drv_data->ide_base,
355 			       adev->pio_mode - XFER_PIO_0);
356 }
357 
358 /* Note: original code is ata_sff_check_status */
359 static u8 ep93xx_pata_check_status(struct ata_port *ap)
360 {
361 	struct ep93xx_pata_data *drv_data = ap->host->private_data;
362 
363 	return ep93xx_pata_read_reg(drv_data, IDECTRL_ADDR_STATUS);
364 }
365 
366 static u8 ep93xx_pata_check_altstatus(struct ata_port *ap)
367 {
368 	struct ep93xx_pata_data *drv_data = ap->host->private_data;
369 
370 	return ep93xx_pata_read_reg(drv_data, IDECTRL_ADDR_ALTSTATUS);
371 }
372 
373 /* Note: original code is ata_sff_tf_load */
374 static void ep93xx_pata_tf_load(struct ata_port *ap,
375 				const struct ata_taskfile *tf)
376 {
377 	struct ep93xx_pata_data *drv_data = ap->host->private_data;
378 	unsigned int is_addr = tf->flags & ATA_TFLAG_ISADDR;
379 
380 	if (tf->ctl != ap->last_ctl) {
381 		ep93xx_pata_write_reg(drv_data, tf->ctl, IDECTRL_ADDR_CTL);
382 		ap->last_ctl = tf->ctl;
383 		ata_wait_idle(ap);
384 	}
385 
386 	if (is_addr && (tf->flags & ATA_TFLAG_LBA48)) {
387 		ep93xx_pata_write_reg(drv_data, tf->hob_feature,
388 			IDECTRL_ADDR_FEATURE);
389 		ep93xx_pata_write_reg(drv_data, tf->hob_nsect,
390 			IDECTRL_ADDR_NSECT);
391 		ep93xx_pata_write_reg(drv_data, tf->hob_lbal,
392 			IDECTRL_ADDR_LBAL);
393 		ep93xx_pata_write_reg(drv_data, tf->hob_lbam,
394 			IDECTRL_ADDR_LBAM);
395 		ep93xx_pata_write_reg(drv_data, tf->hob_lbah,
396 			IDECTRL_ADDR_LBAH);
397 	}
398 
399 	if (is_addr) {
400 		ep93xx_pata_write_reg(drv_data, tf->feature,
401 			IDECTRL_ADDR_FEATURE);
402 		ep93xx_pata_write_reg(drv_data, tf->nsect, IDECTRL_ADDR_NSECT);
403 		ep93xx_pata_write_reg(drv_data, tf->lbal, IDECTRL_ADDR_LBAL);
404 		ep93xx_pata_write_reg(drv_data, tf->lbam, IDECTRL_ADDR_LBAM);
405 		ep93xx_pata_write_reg(drv_data, tf->lbah, IDECTRL_ADDR_LBAH);
406 	}
407 
408 	if (tf->flags & ATA_TFLAG_DEVICE)
409 		ep93xx_pata_write_reg(drv_data, tf->device,
410 			IDECTRL_ADDR_DEVICE);
411 
412 	ata_wait_idle(ap);
413 }
414 
415 /* Note: original code is ata_sff_tf_read */
416 static void ep93xx_pata_tf_read(struct ata_port *ap, struct ata_taskfile *tf)
417 {
418 	struct ep93xx_pata_data *drv_data = ap->host->private_data;
419 
420 	tf->status = ep93xx_pata_check_status(ap);
421 	tf->error = ep93xx_pata_read_reg(drv_data, IDECTRL_ADDR_FEATURE);
422 	tf->nsect = ep93xx_pata_read_reg(drv_data, IDECTRL_ADDR_NSECT);
423 	tf->lbal = ep93xx_pata_read_reg(drv_data, IDECTRL_ADDR_LBAL);
424 	tf->lbam = ep93xx_pata_read_reg(drv_data, IDECTRL_ADDR_LBAM);
425 	tf->lbah = ep93xx_pata_read_reg(drv_data, IDECTRL_ADDR_LBAH);
426 	tf->device = ep93xx_pata_read_reg(drv_data, IDECTRL_ADDR_DEVICE);
427 
428 	if (tf->flags & ATA_TFLAG_LBA48) {
429 		ep93xx_pata_write_reg(drv_data, tf->ctl | ATA_HOB,
430 			IDECTRL_ADDR_CTL);
431 		tf->hob_feature = ep93xx_pata_read_reg(drv_data,
432 			IDECTRL_ADDR_FEATURE);
433 		tf->hob_nsect = ep93xx_pata_read_reg(drv_data,
434 			IDECTRL_ADDR_NSECT);
435 		tf->hob_lbal = ep93xx_pata_read_reg(drv_data,
436 			IDECTRL_ADDR_LBAL);
437 		tf->hob_lbam = ep93xx_pata_read_reg(drv_data,
438 			IDECTRL_ADDR_LBAM);
439 		tf->hob_lbah = ep93xx_pata_read_reg(drv_data,
440 			IDECTRL_ADDR_LBAH);
441 		ep93xx_pata_write_reg(drv_data, tf->ctl, IDECTRL_ADDR_CTL);
442 		ap->last_ctl = tf->ctl;
443 	}
444 }
445 
446 /* Note: original code is ata_sff_exec_command */
447 static void ep93xx_pata_exec_command(struct ata_port *ap,
448 				     const struct ata_taskfile *tf)
449 {
450 	struct ep93xx_pata_data *drv_data = ap->host->private_data;
451 
452 	ep93xx_pata_write_reg(drv_data, tf->command,
453 			  IDECTRL_ADDR_COMMAND);
454 	ata_sff_pause(ap);
455 }
456 
457 /* Note: original code is ata_sff_dev_select */
458 static void ep93xx_pata_dev_select(struct ata_port *ap, unsigned int device)
459 {
460 	struct ep93xx_pata_data *drv_data = ap->host->private_data;
461 	u8 tmp = ATA_DEVICE_OBS;
462 
463 	if (device != 0)
464 		tmp |= ATA_DEV1;
465 
466 	ep93xx_pata_write_reg(drv_data, tmp, IDECTRL_ADDR_DEVICE);
467 	ata_sff_pause(ap);	/* needed; also flushes, for mmio */
468 }
469 
470 /* Note: original code is ata_sff_set_devctl */
471 static void ep93xx_pata_set_devctl(struct ata_port *ap, u8 ctl)
472 {
473 	struct ep93xx_pata_data *drv_data = ap->host->private_data;
474 
475 	ep93xx_pata_write_reg(drv_data, ctl, IDECTRL_ADDR_CTL);
476 }
477 
478 /* Note: original code is ata_sff_data_xfer */
479 static unsigned int ep93xx_pata_data_xfer(struct ata_queued_cmd *qc,
480 					  unsigned char *buf,
481 					  unsigned int buflen, int rw)
482 {
483 	struct ata_port *ap = qc->dev->link->ap;
484 	struct ep93xx_pata_data *drv_data = ap->host->private_data;
485 	u16 *data = (u16 *)buf;
486 	unsigned int words = buflen >> 1;
487 
488 	/* Transfer multiple of 2 bytes */
489 	while (words--)
490 		if (rw == READ)
491 			*data++ = cpu_to_le16(
492 				ep93xx_pata_read_data(
493 					drv_data, IDECTRL_ADDR_DATA));
494 		else
495 			ep93xx_pata_write_data(drv_data, le16_to_cpu(*data++),
496 				IDECTRL_ADDR_DATA);
497 
498 	/* Transfer trailing 1 byte, if any. */
499 	if (unlikely(buflen & 0x01)) {
500 		unsigned char pad[2] = { };
501 
502 		buf += buflen - 1;
503 
504 		if (rw == READ) {
505 			*pad = cpu_to_le16(
506 				ep93xx_pata_read_data(
507 					drv_data, IDECTRL_ADDR_DATA));
508 			*buf = pad[0];
509 		} else {
510 			pad[0] = *buf;
511 			ep93xx_pata_write_data(drv_data, le16_to_cpu(*pad),
512 					  IDECTRL_ADDR_DATA);
513 		}
514 		words++;
515 	}
516 
517 	return words << 1;
518 }
519 
520 /* Note: original code is ata_devchk */
521 static bool ep93xx_pata_device_is_present(struct ata_port *ap,
522 					  unsigned int device)
523 {
524 	struct ep93xx_pata_data *drv_data = ap->host->private_data;
525 	u8 nsect, lbal;
526 
527 	ap->ops->sff_dev_select(ap, device);
528 
529 	ep93xx_pata_write_reg(drv_data, 0x55, IDECTRL_ADDR_NSECT);
530 	ep93xx_pata_write_reg(drv_data, 0xaa, IDECTRL_ADDR_LBAL);
531 
532 	ep93xx_pata_write_reg(drv_data, 0xaa, IDECTRL_ADDR_NSECT);
533 	ep93xx_pata_write_reg(drv_data, 0x55, IDECTRL_ADDR_LBAL);
534 
535 	ep93xx_pata_write_reg(drv_data, 0x55, IDECTRL_ADDR_NSECT);
536 	ep93xx_pata_write_reg(drv_data, 0xaa, IDECTRL_ADDR_LBAL);
537 
538 	nsect = ep93xx_pata_read_reg(drv_data, IDECTRL_ADDR_NSECT);
539 	lbal = ep93xx_pata_read_reg(drv_data, IDECTRL_ADDR_LBAL);
540 
541 	if ((nsect == 0x55) && (lbal == 0xaa))
542 		return true;
543 
544 	return false;
545 }
546 
547 /* Note: original code is ata_sff_wait_after_reset */
548 static int ep93xx_pata_wait_after_reset(struct ata_link *link,
549 					unsigned int devmask,
550 					unsigned long deadline)
551 {
552 	struct ata_port *ap = link->ap;
553 	struct ep93xx_pata_data *drv_data = ap->host->private_data;
554 	unsigned int dev0 = devmask & (1 << 0);
555 	unsigned int dev1 = devmask & (1 << 1);
556 	int rc, ret = 0;
557 
558 	ata_msleep(ap, ATA_WAIT_AFTER_RESET);
559 
560 	/* always check readiness of the master device */
561 	rc = ata_sff_wait_ready(link, deadline);
562 	/*
563 	 * -ENODEV means the odd clown forgot the D7 pulldown resistor
564 	 * and TF status is 0xff, bail out on it too.
565 	 */
566 	if (rc)
567 		return rc;
568 
569 	/*
570 	 * if device 1 was found in ata_devchk, wait for register
571 	 * access briefly, then wait for BSY to clear.
572 	 */
573 	if (dev1) {
574 		int i;
575 
576 		ap->ops->sff_dev_select(ap, 1);
577 
578 		/*
579 		 * Wait for register access.  Some ATAPI devices fail
580 		 * to set nsect/lbal after reset, so don't waste too
581 		 * much time on it.  We're gonna wait for !BSY anyway.
582 		 */
583 		for (i = 0; i < 2; i++) {
584 			u8 nsect, lbal;
585 
586 			nsect = ep93xx_pata_read_reg(drv_data,
587 				IDECTRL_ADDR_NSECT);
588 			lbal = ep93xx_pata_read_reg(drv_data,
589 				IDECTRL_ADDR_LBAL);
590 			if (nsect == 1 && lbal == 1)
591 				break;
592 			msleep(50);	/* give drive a breather */
593 		}
594 
595 		rc = ata_sff_wait_ready(link, deadline);
596 		if (rc) {
597 			if (rc != -ENODEV)
598 				return rc;
599 			ret = rc;
600 		}
601 	}
602 	/* is all this really necessary? */
603 	ap->ops->sff_dev_select(ap, 0);
604 	if (dev1)
605 		ap->ops->sff_dev_select(ap, 1);
606 	if (dev0)
607 		ap->ops->sff_dev_select(ap, 0);
608 
609 	return ret;
610 }
611 
612 /* Note: original code is ata_bus_softreset */
613 static int ep93xx_pata_bus_softreset(struct ata_port *ap, unsigned int devmask,
614 				     unsigned long deadline)
615 {
616 	struct ep93xx_pata_data *drv_data = ap->host->private_data;
617 
618 	ep93xx_pata_write_reg(drv_data, ap->ctl, IDECTRL_ADDR_CTL);
619 	udelay(20);		/* FIXME: flush */
620 	ep93xx_pata_write_reg(drv_data, ap->ctl | ATA_SRST, IDECTRL_ADDR_CTL);
621 	udelay(20);		/* FIXME: flush */
622 	ep93xx_pata_write_reg(drv_data, ap->ctl, IDECTRL_ADDR_CTL);
623 	ap->last_ctl = ap->ctl;
624 
625 	return ep93xx_pata_wait_after_reset(&ap->link, devmask, deadline);
626 }
627 
628 static void ep93xx_pata_release_dma(struct ep93xx_pata_data *drv_data)
629 {
630 	if (drv_data->dma_rx_channel) {
631 		dma_release_channel(drv_data->dma_rx_channel);
632 		drv_data->dma_rx_channel = NULL;
633 	}
634 	if (drv_data->dma_tx_channel) {
635 		dma_release_channel(drv_data->dma_tx_channel);
636 		drv_data->dma_tx_channel = NULL;
637 	}
638 }
639 
640 static bool ep93xx_pata_dma_filter(struct dma_chan *chan, void *filter_param)
641 {
642 	if (ep93xx_dma_chan_is_m2p(chan))
643 		return false;
644 
645 	chan->private = filter_param;
646 	return true;
647 }
648 
649 static void ep93xx_pata_dma_init(struct ep93xx_pata_data *drv_data)
650 {
651 	const struct platform_device *pdev = drv_data->pdev;
652 	dma_cap_mask_t mask;
653 	struct dma_slave_config conf;
654 
655 	dma_cap_zero(mask);
656 	dma_cap_set(DMA_SLAVE, mask);
657 
658 	/*
659 	 * Request two channels for IDE. Another possibility would be
660 	 * to request only one channel, and reprogram it's direction at
661 	 * start of new transfer.
662 	 */
663 	drv_data->dma_rx_data.port = EP93XX_DMA_IDE;
664 	drv_data->dma_rx_data.direction = DMA_DEV_TO_MEM;
665 	drv_data->dma_rx_data.name = "ep93xx-pata-rx";
666 	drv_data->dma_rx_channel = dma_request_channel(mask,
667 		ep93xx_pata_dma_filter, &drv_data->dma_rx_data);
668 	if (!drv_data->dma_rx_channel)
669 		return;
670 
671 	drv_data->dma_tx_data.port = EP93XX_DMA_IDE;
672 	drv_data->dma_tx_data.direction = DMA_MEM_TO_DEV;
673 	drv_data->dma_tx_data.name = "ep93xx-pata-tx";
674 	drv_data->dma_tx_channel = dma_request_channel(mask,
675 		ep93xx_pata_dma_filter, &drv_data->dma_tx_data);
676 	if (!drv_data->dma_tx_channel) {
677 		dma_release_channel(drv_data->dma_rx_channel);
678 		return;
679 	}
680 
681 	/* Configure receive channel direction and source address */
682 	memset(&conf, 0, sizeof(conf));
683 	conf.direction = DMA_DEV_TO_MEM;
684 	conf.src_addr = drv_data->udma_in_phys;
685 	conf.src_addr_width = DMA_SLAVE_BUSWIDTH_4_BYTES;
686 	if (dmaengine_slave_config(drv_data->dma_rx_channel, &conf)) {
687 		dev_err(&pdev->dev, "failed to configure rx dma channel\n");
688 		ep93xx_pata_release_dma(drv_data);
689 		return;
690 	}
691 
692 	/* Configure transmit channel direction and destination address */
693 	memset(&conf, 0, sizeof(conf));
694 	conf.direction = DMA_MEM_TO_DEV;
695 	conf.dst_addr = drv_data->udma_out_phys;
696 	conf.dst_addr_width = DMA_SLAVE_BUSWIDTH_4_BYTES;
697 	if (dmaengine_slave_config(drv_data->dma_tx_channel, &conf)) {
698 		dev_err(&pdev->dev, "failed to configure tx dma channel\n");
699 		ep93xx_pata_release_dma(drv_data);
700 	}
701 }
702 
703 static void ep93xx_pata_dma_start(struct ata_queued_cmd *qc)
704 {
705 	struct dma_async_tx_descriptor *txd;
706 	struct ep93xx_pata_data *drv_data = qc->ap->host->private_data;
707 	void __iomem *base = drv_data->ide_base;
708 	struct ata_device *adev = qc->dev;
709 	u32 v = qc->dma_dir == DMA_TO_DEVICE ? IDEUDMAOP_RWOP : 0;
710 	struct dma_chan *channel = qc->dma_dir == DMA_TO_DEVICE
711 		? drv_data->dma_tx_channel : drv_data->dma_rx_channel;
712 
713 	txd = dmaengine_prep_slave_sg(channel, qc->sg, qc->n_elem, qc->dma_dir,
714 		DMA_CTRL_ACK);
715 	if (!txd) {
716 		dev_err(qc->ap->dev, "failed to prepare slave for sg dma\n");
717 		return;
718 	}
719 	txd->callback = NULL;
720 	txd->callback_param = NULL;
721 
722 	if (dmaengine_submit(txd) < 0) {
723 		dev_err(qc->ap->dev, "failed to submit dma transfer\n");
724 		return;
725 	}
726 	dma_async_issue_pending(channel);
727 
728 	/*
729 	 * When enabling UDMA operation, IDEUDMAOP register needs to be
730 	 * programmed in three step sequence:
731 	 * 1) set or clear the RWOP bit,
732 	 * 2) perform dummy read of the register,
733 	 * 3) set the UEN bit.
734 	 */
735 	writel(v, base + IDEUDMAOP);
736 	readl(base + IDEUDMAOP);
737 	writel(v | IDEUDMAOP_UEN, base + IDEUDMAOP);
738 
739 	writel(IDECFG_IDEEN | IDECFG_UDMA |
740 		((adev->xfer_mode - XFER_UDMA_0) << IDECFG_MODE_SHIFT),
741 		base + IDECFG);
742 }
743 
744 static void ep93xx_pata_dma_stop(struct ata_queued_cmd *qc)
745 {
746 	struct ep93xx_pata_data *drv_data = qc->ap->host->private_data;
747 	void __iomem *base = drv_data->ide_base;
748 
749 	/* terminate all dma transfers, if not yet finished */
750 	dmaengine_terminate_all(drv_data->dma_rx_channel);
751 	dmaengine_terminate_all(drv_data->dma_tx_channel);
752 
753 	/*
754 	 * To properly stop IDE-DMA, IDEUDMAOP register must to be cleared
755 	 * and IDECTRL register must be set to default value.
756 	 */
757 	writel(0, base + IDEUDMAOP);
758 	writel(readl(base + IDECTRL) | IDECTRL_DIOWN | IDECTRL_DIORN |
759 		IDECTRL_CS0N | IDECTRL_CS1N, base + IDECTRL);
760 
761 	ep93xx_pata_enable_pio(drv_data->ide_base,
762 		qc->dev->pio_mode - XFER_PIO_0);
763 
764 	ata_sff_dma_pause(qc->ap);
765 }
766 
767 static void ep93xx_pata_dma_setup(struct ata_queued_cmd *qc)
768 {
769 	qc->ap->ops->sff_exec_command(qc->ap, &qc->tf);
770 }
771 
772 static u8 ep93xx_pata_dma_status(struct ata_port *ap)
773 {
774 	struct ep93xx_pata_data *drv_data = ap->host->private_data;
775 	u32 val = readl(drv_data->ide_base + IDEUDMASTS);
776 
777 	/*
778 	 * UDMA Status Register bits:
779 	 *
780 	 * DMAIDE - DMA request signal from UDMA state machine,
781 	 * INTIDE - INT line generated by UDMA because of errors in the
782 	 *          state machine,
783 	 * SBUSY - UDMA state machine busy, not in idle state,
784 	 * NDO   - error for data-out not completed,
785 	 * NDI   - error for data-in not completed,
786 	 * N4X   - error for data transferred not multiplies of four
787 	 *         32-bit words.
788 	 * (EP93xx UG p27-17)
789 	 */
790 	if (val & IDEUDMASTS_NDO || val & IDEUDMASTS_NDI ||
791 	    val & IDEUDMASTS_N4X || val & IDEUDMASTS_INTIDE)
792 		return ATA_DMA_ERR;
793 
794 	/* read INTRQ (INT[3]) pin input state */
795 	if (readl(drv_data->ide_base + IDECTRL) & IDECTRL_INTRQ)
796 		return ATA_DMA_INTR;
797 
798 	if (val & IDEUDMASTS_SBUSY || val & IDEUDMASTS_DMAIDE)
799 		return ATA_DMA_ACTIVE;
800 
801 	return 0;
802 }
803 
804 /* Note: original code is ata_sff_softreset */
805 static int ep93xx_pata_softreset(struct ata_link *al, unsigned int *classes,
806 				 unsigned long deadline)
807 {
808 	struct ata_port *ap = al->ap;
809 	unsigned int slave_possible = ap->flags & ATA_FLAG_SLAVE_POSS;
810 	unsigned int devmask = 0;
811 	int rc;
812 	u8 err;
813 
814 	/* determine if device 0/1 are present */
815 	if (ep93xx_pata_device_is_present(ap, 0))
816 		devmask |= (1 << 0);
817 	if (slave_possible && ep93xx_pata_device_is_present(ap, 1))
818 		devmask |= (1 << 1);
819 
820 	/* select device 0 again */
821 	ap->ops->sff_dev_select(al->ap, 0);
822 
823 	/* issue bus reset */
824 	rc = ep93xx_pata_bus_softreset(ap, devmask, deadline);
825 	/* if link is ocuppied, -ENODEV too is an error */
826 	if (rc && (rc != -ENODEV || sata_scr_valid(al))) {
827 		ata_link_err(al, "SRST failed (errno=%d)\n", rc);
828 		return rc;
829 	}
830 
831 	/* determine by signature whether we have ATA or ATAPI devices */
832 	classes[0] = ata_sff_dev_classify(&al->device[0], devmask & (1 << 0),
833 					  &err);
834 	if (slave_possible && err != 0x81)
835 		classes[1] = ata_sff_dev_classify(&al->device[1],
836 						  devmask & (1 << 1), &err);
837 
838 	return 0;
839 }
840 
841 /* Note: original code is ata_sff_drain_fifo */
842 static void ep93xx_pata_drain_fifo(struct ata_queued_cmd *qc)
843 {
844 	int count;
845 	struct ata_port *ap;
846 	struct ep93xx_pata_data *drv_data;
847 
848 	/* We only need to flush incoming data when a command was running */
849 	if (qc == NULL || qc->dma_dir == DMA_TO_DEVICE)
850 		return;
851 
852 	ap = qc->ap;
853 	drv_data = ap->host->private_data;
854 	/* Drain up to 64K of data before we give up this recovery method */
855 	for (count = 0; (ap->ops->sff_check_status(ap) & ATA_DRQ)
856 		     && count < 65536; count += 2)
857 		ep93xx_pata_read_reg(drv_data, IDECTRL_ADDR_DATA);
858 
859 	if (count)
860 		ata_port_dbg(ap, "drained %d bytes to clear DRQ.\n", count);
861 
862 }
863 
864 static int ep93xx_pata_port_start(struct ata_port *ap)
865 {
866 	struct ep93xx_pata_data *drv_data = ap->host->private_data;
867 
868 	/*
869 	 * Set timings to safe values at startup (= number of ns from ATA
870 	 * specification), we'll switch to properly calculated values later.
871 	 */
872 	drv_data->t = *ata_timing_find_mode(XFER_PIO_0);
873 	return 0;
874 }
875 
876 static const struct scsi_host_template ep93xx_pata_sht = {
877 	ATA_BASE_SHT(DRV_NAME),
878 	/* ep93xx dma implementation limit */
879 	.sg_tablesize		= 32,
880 	/* ep93xx dma can't transfer 65536 bytes at once */
881 	.dma_boundary		= 0x7fff,
882 };
883 
884 static struct ata_port_operations ep93xx_pata_port_ops = {
885 	.inherits		= &ata_bmdma_port_ops,
886 
887 	.qc_prep		= ata_noop_qc_prep,
888 
889 	.softreset		= ep93xx_pata_softreset,
890 	.hardreset		= ATA_OP_NULL,
891 
892 	.sff_dev_select		= ep93xx_pata_dev_select,
893 	.sff_set_devctl		= ep93xx_pata_set_devctl,
894 	.sff_check_status	= ep93xx_pata_check_status,
895 	.sff_check_altstatus	= ep93xx_pata_check_altstatus,
896 	.sff_tf_load		= ep93xx_pata_tf_load,
897 	.sff_tf_read		= ep93xx_pata_tf_read,
898 	.sff_exec_command	= ep93xx_pata_exec_command,
899 	.sff_data_xfer		= ep93xx_pata_data_xfer,
900 	.sff_drain_fifo		= ep93xx_pata_drain_fifo,
901 	.sff_irq_clear		= ATA_OP_NULL,
902 
903 	.set_piomode		= ep93xx_pata_set_piomode,
904 
905 	.bmdma_setup		= ep93xx_pata_dma_setup,
906 	.bmdma_start		= ep93xx_pata_dma_start,
907 	.bmdma_stop		= ep93xx_pata_dma_stop,
908 	.bmdma_status		= ep93xx_pata_dma_status,
909 
910 	.cable_detect		= ata_cable_unknown,
911 	.port_start		= ep93xx_pata_port_start,
912 };
913 
914 static const struct soc_device_attribute ep93xx_soc_table[] = {
915 	{ .revision = "E1", .data = (void *)ATA_UDMA3 },
916 	{ .revision = "E2", .data = (void *)ATA_UDMA4 },
917 	{ /* sentinel */ }
918 };
919 
920 static int ep93xx_pata_probe(struct platform_device *pdev)
921 {
922 	struct ep93xx_pata_data *drv_data;
923 	struct ata_host *host;
924 	struct ata_port *ap;
925 	int irq;
926 	struct resource *mem_res;
927 	void __iomem *ide_base;
928 	int err;
929 
930 	err = ep93xx_ide_acquire_gpio(pdev);
931 	if (err)
932 		return err;
933 
934 	/* INT[3] (IRQ_EP93XX_EXT3) line connected as pull down */
935 	irq = platform_get_irq(pdev, 0);
936 	if (irq < 0) {
937 		err = irq;
938 		goto err_rel_gpio;
939 	}
940 
941 	ide_base = devm_platform_get_and_ioremap_resource(pdev, 0, &mem_res);
942 	if (IS_ERR(ide_base)) {
943 		err = PTR_ERR(ide_base);
944 		goto err_rel_gpio;
945 	}
946 
947 	drv_data = devm_kzalloc(&pdev->dev, sizeof(*drv_data), GFP_KERNEL);
948 	if (!drv_data) {
949 		err = -ENOMEM;
950 		goto err_rel_gpio;
951 	}
952 
953 	drv_data->pdev = pdev;
954 	drv_data->ide_base = ide_base;
955 	drv_data->udma_in_phys = mem_res->start + IDEUDMADATAIN;
956 	drv_data->udma_out_phys = mem_res->start + IDEUDMADATAOUT;
957 	ep93xx_pata_dma_init(drv_data);
958 
959 	/* allocate host */
960 	host = ata_host_alloc(&pdev->dev, 1);
961 	if (!host) {
962 		err = -ENOMEM;
963 		goto err_rel_dma;
964 	}
965 
966 	ep93xx_pata_clear_regs(ide_base);
967 
968 	host->private_data = drv_data;
969 
970 	ap = host->ports[0];
971 	ap->dev = &pdev->dev;
972 	ap->ops = &ep93xx_pata_port_ops;
973 	ap->flags |= ATA_FLAG_SLAVE_POSS;
974 	ap->pio_mask = ATA_PIO4;
975 
976 	/*
977 	 * Maximum UDMA modes:
978 	 * EP931x rev.E0 - UDMA2
979 	 * EP931x rev.E1 - UDMA3
980 	 * EP931x rev.E2 - UDMA4
981 	 *
982 	 * MWDMA support was removed from EP931x rev.E2,
983 	 * so this driver supports only UDMA modes.
984 	 */
985 	if (drv_data->dma_rx_channel && drv_data->dma_tx_channel) {
986 		const struct soc_device_attribute *match;
987 
988 		match = soc_device_match(ep93xx_soc_table);
989 		if (match)
990 			ap->udma_mask = (unsigned int) match->data;
991 		else
992 			ap->udma_mask = ATA_UDMA2;
993 	}
994 
995 	/* defaults, pio 0 */
996 	ep93xx_pata_enable_pio(ide_base, 0);
997 
998 	dev_info(&pdev->dev, "version " DRV_VERSION "\n");
999 
1000 	/* activate host */
1001 	err = ata_host_activate(host, irq, ata_bmdma_interrupt, 0,
1002 		&ep93xx_pata_sht);
1003 	if (err == 0)
1004 		return 0;
1005 
1006 err_rel_dma:
1007 	ep93xx_pata_release_dma(drv_data);
1008 err_rel_gpio:
1009 	ep93xx_ide_release_gpio(pdev);
1010 	return err;
1011 }
1012 
1013 static void ep93xx_pata_remove(struct platform_device *pdev)
1014 {
1015 	struct ata_host *host = platform_get_drvdata(pdev);
1016 	struct ep93xx_pata_data *drv_data = host->private_data;
1017 
1018 	ata_host_detach(host);
1019 	ep93xx_pata_release_dma(drv_data);
1020 	ep93xx_pata_clear_regs(drv_data->ide_base);
1021 	ep93xx_ide_release_gpio(pdev);
1022 }
1023 
1024 static struct platform_driver ep93xx_pata_platform_driver = {
1025 	.driver = {
1026 		.name = DRV_NAME,
1027 	},
1028 	.probe = ep93xx_pata_probe,
1029 	.remove_new = ep93xx_pata_remove,
1030 };
1031 
1032 module_platform_driver(ep93xx_pata_platform_driver);
1033 
1034 MODULE_AUTHOR("Alessandro Zummo, Lennert Buytenhek, Joao Ramos, "
1035 		"Bartlomiej Zolnierkiewicz, Rafal Prylowski");
1036 MODULE_DESCRIPTION("low-level driver for cirrus ep93xx IDE controller");
1037 MODULE_LICENSE("GPL");
1038 MODULE_VERSION(DRV_VERSION);
1039 MODULE_ALIAS("platform:pata_ep93xx");
1040