xref: /openbmc/linux/drivers/ata/pata_ep93xx.c (revision 9a29f5fc)
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/delay.h>
44 #include <linux/dmaengine.h>
45 #include <linux/ktime.h>
46 
47 #include <linux/platform_data/dma-ep93xx.h>
48 #include <linux/soc/cirrus/ep93xx.h>
49 
50 #define DRV_NAME	"ep93xx-ide"
51 #define DRV_VERSION	"1.0"
52 
53 enum {
54 	/* IDE Control Register */
55 	IDECTRL				= 0x00,
56 	IDECTRL_CS0N			= (1 << 0),
57 	IDECTRL_CS1N			= (1 << 1),
58 	IDECTRL_DIORN			= (1 << 5),
59 	IDECTRL_DIOWN			= (1 << 6),
60 	IDECTRL_INTRQ			= (1 << 9),
61 	IDECTRL_IORDY			= (1 << 10),
62 	/*
63 	 * the device IDE register to be accessed is selected through
64 	 * IDECTRL register's specific bitfields 'DA', 'CS1N' and 'CS0N':
65 	 *   b4   b3   b2    b1     b0
66 	 *   A2   A1   A0   CS1N   CS0N
67 	 * the values filled in this structure allows the value to be directly
68 	 * ORed to the IDECTRL register, hence giving directly the A[2:0] and
69 	 * CS1N/CS0N values for each IDE register.
70 	 * The values correspond to the transformation:
71 	 *   ((real IDE address) << 2) | CS1N value << 1 | CS0N value
72 	 */
73 	IDECTRL_ADDR_CMD		= 0 + 2, /* CS1 */
74 	IDECTRL_ADDR_DATA		= (ATA_REG_DATA << 2) + 2,
75 	IDECTRL_ADDR_ERROR		= (ATA_REG_ERR << 2) + 2,
76 	IDECTRL_ADDR_FEATURE		= (ATA_REG_FEATURE << 2) + 2,
77 	IDECTRL_ADDR_NSECT		= (ATA_REG_NSECT << 2) + 2,
78 	IDECTRL_ADDR_LBAL		= (ATA_REG_LBAL << 2) + 2,
79 	IDECTRL_ADDR_LBAM		= (ATA_REG_LBAM << 2) + 2,
80 	IDECTRL_ADDR_LBAH		= (ATA_REG_LBAH << 2) + 2,
81 	IDECTRL_ADDR_DEVICE		= (ATA_REG_DEVICE << 2) + 2,
82 	IDECTRL_ADDR_STATUS		= (ATA_REG_STATUS << 2) + 2,
83 	IDECTRL_ADDR_COMMAND		= (ATA_REG_CMD << 2) + 2,
84 	IDECTRL_ADDR_ALTSTATUS		= (0x06 << 2) + 1, /* CS0 */
85 	IDECTRL_ADDR_CTL		= (0x06 << 2) + 1, /* CS0 */
86 
87 	/* IDE Configuration Register */
88 	IDECFG				= 0x04,
89 	IDECFG_IDEEN			= (1 << 0),
90 	IDECFG_PIO			= (1 << 1),
91 	IDECFG_MDMA			= (1 << 2),
92 	IDECFG_UDMA			= (1 << 3),
93 	IDECFG_MODE_SHIFT		= 4,
94 	IDECFG_MODE_MASK		= (0xf << 4),
95 	IDECFG_WST_SHIFT		= 8,
96 	IDECFG_WST_MASK			= (0x3 << 8),
97 
98 	/* MDMA Operation Register */
99 	IDEMDMAOP			= 0x08,
100 
101 	/* UDMA Operation Register */
102 	IDEUDMAOP			= 0x0c,
103 	IDEUDMAOP_UEN			= (1 << 0),
104 	IDEUDMAOP_RWOP			= (1 << 1),
105 
106 	/* PIO/MDMA/UDMA Data Registers */
107 	IDEDATAOUT			= 0x10,
108 	IDEDATAIN			= 0x14,
109 	IDEMDMADATAOUT			= 0x18,
110 	IDEMDMADATAIN			= 0x1c,
111 	IDEUDMADATAOUT			= 0x20,
112 	IDEUDMADATAIN			= 0x24,
113 
114 	/* UDMA Status Register */
115 	IDEUDMASTS			= 0x28,
116 	IDEUDMASTS_DMAIDE		= (1 << 16),
117 	IDEUDMASTS_INTIDE		= (1 << 17),
118 	IDEUDMASTS_SBUSY		= (1 << 18),
119 	IDEUDMASTS_NDO			= (1 << 24),
120 	IDEUDMASTS_NDI			= (1 << 25),
121 	IDEUDMASTS_N4X			= (1 << 26),
122 
123 	/* UDMA Debug Status Register */
124 	IDEUDMADEBUG			= 0x2c,
125 };
126 
127 struct ep93xx_pata_data {
128 	const struct platform_device *pdev;
129 	void __iomem *ide_base;
130 	struct ata_timing t;
131 	bool iordy;
132 
133 	unsigned long udma_in_phys;
134 	unsigned long udma_out_phys;
135 
136 	struct dma_chan *dma_rx_channel;
137 	struct ep93xx_dma_data dma_rx_data;
138 	struct dma_chan *dma_tx_channel;
139 	struct ep93xx_dma_data dma_tx_data;
140 };
141 
142 static void ep93xx_pata_clear_regs(void __iomem *base)
143 {
144 	writel(IDECTRL_CS0N | IDECTRL_CS1N | IDECTRL_DIORN |
145 		IDECTRL_DIOWN, base + IDECTRL);
146 
147 	writel(0, base + IDECFG);
148 	writel(0, base + IDEMDMAOP);
149 	writel(0, base + IDEUDMAOP);
150 	writel(0, base + IDEDATAOUT);
151 	writel(0, base + IDEDATAIN);
152 	writel(0, base + IDEMDMADATAOUT);
153 	writel(0, base + IDEMDMADATAIN);
154 	writel(0, base + IDEUDMADATAOUT);
155 	writel(0, base + IDEUDMADATAIN);
156 	writel(0, base + IDEUDMADEBUG);
157 }
158 
159 static bool ep93xx_pata_check_iordy(void __iomem *base)
160 {
161 	return !!(readl(base + IDECTRL) & IDECTRL_IORDY);
162 }
163 
164 /*
165  * According to EP93xx User's Guide, WST field of IDECFG specifies number
166  * of HCLK cycles to hold the data bus after a PIO write operation.
167  * It should be programmed to guarantee following delays:
168  *
169  * PIO Mode   [ns]
170  * 0          30
171  * 1          20
172  * 2          15
173  * 3          10
174  * 4          5
175  *
176  * Maximum possible value for HCLK is 100MHz.
177  */
178 static int ep93xx_pata_get_wst(int pio_mode)
179 {
180 	int val;
181 
182 	if (pio_mode == 0)
183 		val = 3;
184 	else if (pio_mode < 3)
185 		val = 2;
186 	else
187 		val = 1;
188 
189 	return val << IDECFG_WST_SHIFT;
190 }
191 
192 static void ep93xx_pata_enable_pio(void __iomem *base, int pio_mode)
193 {
194 	writel(IDECFG_IDEEN | IDECFG_PIO |
195 		ep93xx_pata_get_wst(pio_mode) |
196 		(pio_mode << IDECFG_MODE_SHIFT), base + IDECFG);
197 }
198 
199 /*
200  * Based on delay loop found in mach-pxa/mp900.c.
201  *
202  * Single iteration should take 5 cpu cycles. This is 25ns assuming the
203  * fastest ep93xx cpu speed (200MHz) and is better optimized for PIO4 timings
204  * than eg. 20ns.
205  */
206 static void ep93xx_pata_delay(unsigned long count)
207 {
208 	__asm__ volatile (
209 		"0:\n"
210 		"mov r0, r0\n"
211 		"subs %0, %1, #1\n"
212 		"bge 0b\n"
213 		: "=r" (count)
214 		: "0" (count)
215 	);
216 }
217 
218 static unsigned long ep93xx_pata_wait_for_iordy(void __iomem *base,
219 						unsigned long t2)
220 {
221 	/*
222 	 * According to ATA specification, IORDY pin can be first sampled
223 	 * tA = 35ns after activation of DIOR-/DIOW-. Maximum IORDY pulse
224 	 * width is tB = 1250ns.
225 	 *
226 	 * We are already t2 delay loop iterations after activation of
227 	 * DIOR-/DIOW-, so we set timeout to (1250 + 35) / 25 - t2 additional
228 	 * delay loop iterations.
229 	 */
230 	unsigned long start = (1250 + 35) / 25 - t2;
231 	unsigned long counter = start;
232 
233 	while (!ep93xx_pata_check_iordy(base) && counter--)
234 		ep93xx_pata_delay(1);
235 	return start - counter;
236 }
237 
238 /* common part at start of ep93xx_pata_read/write() */
239 static void ep93xx_pata_rw_begin(void __iomem *base, unsigned long addr,
240 				 unsigned long t1)
241 {
242 	writel(IDECTRL_DIOWN | IDECTRL_DIORN | addr, base + IDECTRL);
243 	ep93xx_pata_delay(t1);
244 }
245 
246 /* common part at end of ep93xx_pata_read/write() */
247 static void ep93xx_pata_rw_end(void __iomem *base, unsigned long addr,
248 			       bool iordy, unsigned long t0, unsigned long t2,
249 			       unsigned long t2i)
250 {
251 	ep93xx_pata_delay(t2);
252 	/* lengthen t2 if needed */
253 	if (iordy)
254 		t2 += ep93xx_pata_wait_for_iordy(base, t2);
255 	writel(IDECTRL_DIOWN | IDECTRL_DIORN | addr, base + IDECTRL);
256 	if (t0 > t2 && t0 - t2 > t2i)
257 		ep93xx_pata_delay(t0 - t2);
258 	else
259 		ep93xx_pata_delay(t2i);
260 }
261 
262 static u16 ep93xx_pata_read(struct ep93xx_pata_data *drv_data,
263 			    unsigned long addr,
264 			    bool reg)
265 {
266 	void __iomem *base = drv_data->ide_base;
267 	const struct ata_timing *t = &drv_data->t;
268 	unsigned long t0 = reg ? t->cyc8b : t->cycle;
269 	unsigned long t2 = reg ? t->act8b : t->active;
270 	unsigned long t2i = reg ? t->rec8b : t->recover;
271 
272 	ep93xx_pata_rw_begin(base, addr, t->setup);
273 	writel(IDECTRL_DIOWN | addr, base + IDECTRL);
274 	/*
275 	 * The IDEDATAIN register is loaded from the DD pins at the positive
276 	 * edge of the DIORN signal. (EP93xx UG p27-14)
277 	 */
278 	ep93xx_pata_rw_end(base, addr, drv_data->iordy, t0, t2, t2i);
279 	return readl(base + IDEDATAIN);
280 }
281 
282 /* IDE register read */
283 static u16 ep93xx_pata_read_reg(struct ep93xx_pata_data *drv_data,
284 				unsigned long addr)
285 {
286 	return ep93xx_pata_read(drv_data, addr, true);
287 }
288 
289 /* PIO data read */
290 static u16 ep93xx_pata_read_data(struct ep93xx_pata_data *drv_data,
291 				 unsigned long addr)
292 {
293 	return ep93xx_pata_read(drv_data, addr, false);
294 }
295 
296 static void ep93xx_pata_write(struct ep93xx_pata_data *drv_data,
297 			      u16 value, unsigned long addr,
298 			      bool reg)
299 {
300 	void __iomem *base = drv_data->ide_base;
301 	const struct ata_timing *t = &drv_data->t;
302 	unsigned long t0 = reg ? t->cyc8b : t->cycle;
303 	unsigned long t2 = reg ? t->act8b : t->active;
304 	unsigned long t2i = reg ? t->rec8b : t->recover;
305 
306 	ep93xx_pata_rw_begin(base, addr, t->setup);
307 	/*
308 	 * Value from IDEDATAOUT register is driven onto the DD pins when
309 	 * DIOWN is low. (EP93xx UG p27-13)
310 	 */
311 	writel(value, base + IDEDATAOUT);
312 	writel(IDECTRL_DIORN | addr, base + IDECTRL);
313 	ep93xx_pata_rw_end(base, addr, drv_data->iordy, t0, t2, t2i);
314 }
315 
316 /* IDE register write */
317 static void ep93xx_pata_write_reg(struct ep93xx_pata_data *drv_data,
318 				  u16 value, unsigned long addr)
319 {
320 	ep93xx_pata_write(drv_data, value, addr, true);
321 }
322 
323 /* PIO data write */
324 static void ep93xx_pata_write_data(struct ep93xx_pata_data *drv_data,
325 				   u16 value, unsigned long addr)
326 {
327 	ep93xx_pata_write(drv_data, value, addr, false);
328 }
329 
330 static void ep93xx_pata_set_piomode(struct ata_port *ap,
331 				    struct ata_device *adev)
332 {
333 	struct ep93xx_pata_data *drv_data = ap->host->private_data;
334 	struct ata_device *pair = ata_dev_pair(adev);
335 	/*
336 	 * Calculate timings for the delay loop, assuming ep93xx cpu speed
337 	 * is 200MHz (maximum possible for ep93xx). If actual cpu speed is
338 	 * slower, we will wait a bit longer in each delay.
339 	 * Additional division of cpu speed by 5, because single iteration
340 	 * of our delay loop takes 5 cpu cycles (25ns).
341 	 */
342 	unsigned long T = 1000000 / (200 / 5);
343 
344 	ata_timing_compute(adev, adev->pio_mode, &drv_data->t, T, 0);
345 	if (pair && pair->pio_mode) {
346 		struct ata_timing t;
347 		ata_timing_compute(pair, pair->pio_mode, &t, T, 0);
348 		ata_timing_merge(&t, &drv_data->t, &drv_data->t,
349 			ATA_TIMING_SETUP | ATA_TIMING_8BIT);
350 	}
351 	drv_data->iordy = ata_pio_need_iordy(adev);
352 
353 	ep93xx_pata_enable_pio(drv_data->ide_base,
354 			       adev->pio_mode - XFER_PIO_0);
355 }
356 
357 /* Note: original code is ata_sff_check_status */
358 static u8 ep93xx_pata_check_status(struct ata_port *ap)
359 {
360 	struct ep93xx_pata_data *drv_data = ap->host->private_data;
361 
362 	return ep93xx_pata_read_reg(drv_data, IDECTRL_ADDR_STATUS);
363 }
364 
365 static u8 ep93xx_pata_check_altstatus(struct ata_port *ap)
366 {
367 	struct ep93xx_pata_data *drv_data = ap->host->private_data;
368 
369 	return ep93xx_pata_read_reg(drv_data, IDECTRL_ADDR_ALTSTATUS);
370 }
371 
372 /* Note: original code is ata_sff_tf_load */
373 static void ep93xx_pata_tf_load(struct ata_port *ap,
374 				const struct ata_taskfile *tf)
375 {
376 	struct ep93xx_pata_data *drv_data = ap->host->private_data;
377 	unsigned int is_addr = tf->flags & ATA_TFLAG_ISADDR;
378 
379 	if (tf->ctl != ap->last_ctl) {
380 		ep93xx_pata_write_reg(drv_data, tf->ctl, IDECTRL_ADDR_CTL);
381 		ap->last_ctl = tf->ctl;
382 		ata_wait_idle(ap);
383 	}
384 
385 	if (is_addr && (tf->flags & ATA_TFLAG_LBA48)) {
386 		ep93xx_pata_write_reg(drv_data, tf->hob_feature,
387 			IDECTRL_ADDR_FEATURE);
388 		ep93xx_pata_write_reg(drv_data, tf->hob_nsect,
389 			IDECTRL_ADDR_NSECT);
390 		ep93xx_pata_write_reg(drv_data, tf->hob_lbal,
391 			IDECTRL_ADDR_LBAL);
392 		ep93xx_pata_write_reg(drv_data, tf->hob_lbam,
393 			IDECTRL_ADDR_LBAM);
394 		ep93xx_pata_write_reg(drv_data, tf->hob_lbah,
395 			IDECTRL_ADDR_LBAH);
396 	}
397 
398 	if (is_addr) {
399 		ep93xx_pata_write_reg(drv_data, tf->feature,
400 			IDECTRL_ADDR_FEATURE);
401 		ep93xx_pata_write_reg(drv_data, tf->nsect, IDECTRL_ADDR_NSECT);
402 		ep93xx_pata_write_reg(drv_data, tf->lbal, IDECTRL_ADDR_LBAL);
403 		ep93xx_pata_write_reg(drv_data, tf->lbam, IDECTRL_ADDR_LBAM);
404 		ep93xx_pata_write_reg(drv_data, tf->lbah, IDECTRL_ADDR_LBAH);
405 	}
406 
407 	if (tf->flags & ATA_TFLAG_DEVICE)
408 		ep93xx_pata_write_reg(drv_data, tf->device,
409 			IDECTRL_ADDR_DEVICE);
410 
411 	ata_wait_idle(ap);
412 }
413 
414 /* Note: original code is ata_sff_tf_read */
415 static void ep93xx_pata_tf_read(struct ata_port *ap, struct ata_taskfile *tf)
416 {
417 	struct ep93xx_pata_data *drv_data = ap->host->private_data;
418 
419 	tf->status = ep93xx_pata_check_status(ap);
420 	tf->error = ep93xx_pata_read_reg(drv_data, IDECTRL_ADDR_FEATURE);
421 	tf->nsect = ep93xx_pata_read_reg(drv_data, IDECTRL_ADDR_NSECT);
422 	tf->lbal = ep93xx_pata_read_reg(drv_data, IDECTRL_ADDR_LBAL);
423 	tf->lbam = ep93xx_pata_read_reg(drv_data, IDECTRL_ADDR_LBAM);
424 	tf->lbah = ep93xx_pata_read_reg(drv_data, IDECTRL_ADDR_LBAH);
425 	tf->device = ep93xx_pata_read_reg(drv_data, IDECTRL_ADDR_DEVICE);
426 
427 	if (tf->flags & ATA_TFLAG_LBA48) {
428 		ep93xx_pata_write_reg(drv_data, tf->ctl | ATA_HOB,
429 			IDECTRL_ADDR_CTL);
430 		tf->hob_feature = ep93xx_pata_read_reg(drv_data,
431 			IDECTRL_ADDR_FEATURE);
432 		tf->hob_nsect = ep93xx_pata_read_reg(drv_data,
433 			IDECTRL_ADDR_NSECT);
434 		tf->hob_lbal = ep93xx_pata_read_reg(drv_data,
435 			IDECTRL_ADDR_LBAL);
436 		tf->hob_lbam = ep93xx_pata_read_reg(drv_data,
437 			IDECTRL_ADDR_LBAM);
438 		tf->hob_lbah = ep93xx_pata_read_reg(drv_data,
439 			IDECTRL_ADDR_LBAH);
440 		ep93xx_pata_write_reg(drv_data, tf->ctl, IDECTRL_ADDR_CTL);
441 		ap->last_ctl = tf->ctl;
442 	}
443 }
444 
445 /* Note: original code is ata_sff_exec_command */
446 static void ep93xx_pata_exec_command(struct ata_port *ap,
447 				     const struct ata_taskfile *tf)
448 {
449 	struct ep93xx_pata_data *drv_data = ap->host->private_data;
450 
451 	ep93xx_pata_write_reg(drv_data, tf->command,
452 			  IDECTRL_ADDR_COMMAND);
453 	ata_sff_pause(ap);
454 }
455 
456 /* Note: original code is ata_sff_dev_select */
457 static void ep93xx_pata_dev_select(struct ata_port *ap, unsigned int device)
458 {
459 	struct ep93xx_pata_data *drv_data = ap->host->private_data;
460 	u8 tmp = ATA_DEVICE_OBS;
461 
462 	if (device != 0)
463 		tmp |= ATA_DEV1;
464 
465 	ep93xx_pata_write_reg(drv_data, tmp, IDECTRL_ADDR_DEVICE);
466 	ata_sff_pause(ap);	/* needed; also flushes, for mmio */
467 }
468 
469 /* Note: original code is ata_sff_set_devctl */
470 static void ep93xx_pata_set_devctl(struct ata_port *ap, u8 ctl)
471 {
472 	struct ep93xx_pata_data *drv_data = ap->host->private_data;
473 
474 	ep93xx_pata_write_reg(drv_data, ctl, IDECTRL_ADDR_CTL);
475 }
476 
477 /* Note: original code is ata_sff_data_xfer */
478 static unsigned int ep93xx_pata_data_xfer(struct ata_queued_cmd *qc,
479 					  unsigned char *buf,
480 					  unsigned int buflen, int rw)
481 {
482 	struct ata_port *ap = qc->dev->link->ap;
483 	struct ep93xx_pata_data *drv_data = ap->host->private_data;
484 	u16 *data = (u16 *)buf;
485 	unsigned int words = buflen >> 1;
486 
487 	/* Transfer multiple of 2 bytes */
488 	while (words--)
489 		if (rw == READ)
490 			*data++ = cpu_to_le16(
491 				ep93xx_pata_read_data(
492 					drv_data, IDECTRL_ADDR_DATA));
493 		else
494 			ep93xx_pata_write_data(drv_data, le16_to_cpu(*data++),
495 				IDECTRL_ADDR_DATA);
496 
497 	/* Transfer trailing 1 byte, if any. */
498 	if (unlikely(buflen & 0x01)) {
499 		unsigned char pad[2] = { };
500 
501 		buf += buflen - 1;
502 
503 		if (rw == READ) {
504 			*pad = cpu_to_le16(
505 				ep93xx_pata_read_data(
506 					drv_data, IDECTRL_ADDR_DATA));
507 			*buf = pad[0];
508 		} else {
509 			pad[0] = *buf;
510 			ep93xx_pata_write_data(drv_data, le16_to_cpu(*pad),
511 					  IDECTRL_ADDR_DATA);
512 		}
513 		words++;
514 	}
515 
516 	return words << 1;
517 }
518 
519 /* Note: original code is ata_devchk */
520 static bool ep93xx_pata_device_is_present(struct ata_port *ap,
521 					  unsigned int device)
522 {
523 	struct ep93xx_pata_data *drv_data = ap->host->private_data;
524 	u8 nsect, lbal;
525 
526 	ap->ops->sff_dev_select(ap, device);
527 
528 	ep93xx_pata_write_reg(drv_data, 0x55, IDECTRL_ADDR_NSECT);
529 	ep93xx_pata_write_reg(drv_data, 0xaa, IDECTRL_ADDR_LBAL);
530 
531 	ep93xx_pata_write_reg(drv_data, 0xaa, IDECTRL_ADDR_NSECT);
532 	ep93xx_pata_write_reg(drv_data, 0x55, IDECTRL_ADDR_LBAL);
533 
534 	ep93xx_pata_write_reg(drv_data, 0x55, IDECTRL_ADDR_NSECT);
535 	ep93xx_pata_write_reg(drv_data, 0xaa, IDECTRL_ADDR_LBAL);
536 
537 	nsect = ep93xx_pata_read_reg(drv_data, IDECTRL_ADDR_NSECT);
538 	lbal = ep93xx_pata_read_reg(drv_data, IDECTRL_ADDR_LBAL);
539 
540 	if ((nsect == 0x55) && (lbal == 0xaa))
541 		return true;
542 
543 	return false;
544 }
545 
546 /* Note: original code is ata_sff_wait_after_reset */
547 static int ep93xx_pata_wait_after_reset(struct ata_link *link,
548 					unsigned int devmask,
549 					unsigned long deadline)
550 {
551 	struct ata_port *ap = link->ap;
552 	struct ep93xx_pata_data *drv_data = ap->host->private_data;
553 	unsigned int dev0 = devmask & (1 << 0);
554 	unsigned int dev1 = devmask & (1 << 1);
555 	int rc, ret = 0;
556 
557 	ata_msleep(ap, ATA_WAIT_AFTER_RESET);
558 
559 	/* always check readiness of the master device */
560 	rc = ata_sff_wait_ready(link, deadline);
561 	/*
562 	 * -ENODEV means the odd clown forgot the D7 pulldown resistor
563 	 * and TF status is 0xff, bail out on it too.
564 	 */
565 	if (rc)
566 		return rc;
567 
568 	/*
569 	 * if device 1 was found in ata_devchk, wait for register
570 	 * access briefly, then wait for BSY to clear.
571 	 */
572 	if (dev1) {
573 		int i;
574 
575 		ap->ops->sff_dev_select(ap, 1);
576 
577 		/*
578 		 * Wait for register access.  Some ATAPI devices fail
579 		 * to set nsect/lbal after reset, so don't waste too
580 		 * much time on it.  We're gonna wait for !BSY anyway.
581 		 */
582 		for (i = 0; i < 2; i++) {
583 			u8 nsect, lbal;
584 
585 			nsect = ep93xx_pata_read_reg(drv_data,
586 				IDECTRL_ADDR_NSECT);
587 			lbal = ep93xx_pata_read_reg(drv_data,
588 				IDECTRL_ADDR_LBAL);
589 			if (nsect == 1 && lbal == 1)
590 				break;
591 			msleep(50);	/* give drive a breather */
592 		}
593 
594 		rc = ata_sff_wait_ready(link, deadline);
595 		if (rc) {
596 			if (rc != -ENODEV)
597 				return rc;
598 			ret = rc;
599 		}
600 	}
601 	/* is all this really necessary? */
602 	ap->ops->sff_dev_select(ap, 0);
603 	if (dev1)
604 		ap->ops->sff_dev_select(ap, 1);
605 	if (dev0)
606 		ap->ops->sff_dev_select(ap, 0);
607 
608 	return ret;
609 }
610 
611 /* Note: original code is ata_bus_softreset */
612 static int ep93xx_pata_bus_softreset(struct ata_port *ap, unsigned int devmask,
613 				     unsigned long deadline)
614 {
615 	struct ep93xx_pata_data *drv_data = ap->host->private_data;
616 
617 	ep93xx_pata_write_reg(drv_data, ap->ctl, IDECTRL_ADDR_CTL);
618 	udelay(20);		/* FIXME: flush */
619 	ep93xx_pata_write_reg(drv_data, ap->ctl | ATA_SRST, IDECTRL_ADDR_CTL);
620 	udelay(20);		/* FIXME: flush */
621 	ep93xx_pata_write_reg(drv_data, ap->ctl, IDECTRL_ADDR_CTL);
622 	ap->last_ctl = ap->ctl;
623 
624 	return ep93xx_pata_wait_after_reset(&ap->link, devmask, deadline);
625 }
626 
627 static void ep93xx_pata_release_dma(struct ep93xx_pata_data *drv_data)
628 {
629 	if (drv_data->dma_rx_channel) {
630 		dma_release_channel(drv_data->dma_rx_channel);
631 		drv_data->dma_rx_channel = NULL;
632 	}
633 	if (drv_data->dma_tx_channel) {
634 		dma_release_channel(drv_data->dma_tx_channel);
635 		drv_data->dma_tx_channel = NULL;
636 	}
637 }
638 
639 static bool ep93xx_pata_dma_filter(struct dma_chan *chan, void *filter_param)
640 {
641 	if (ep93xx_dma_chan_is_m2p(chan))
642 		return false;
643 
644 	chan->private = filter_param;
645 	return true;
646 }
647 
648 static void ep93xx_pata_dma_init(struct ep93xx_pata_data *drv_data)
649 {
650 	const struct platform_device *pdev = drv_data->pdev;
651 	dma_cap_mask_t mask;
652 	struct dma_slave_config conf;
653 
654 	dma_cap_zero(mask);
655 	dma_cap_set(DMA_SLAVE, mask);
656 
657 	/*
658 	 * Request two channels for IDE. Another possibility would be
659 	 * to request only one channel, and reprogram it's direction at
660 	 * start of new transfer.
661 	 */
662 	drv_data->dma_rx_data.port = EP93XX_DMA_IDE;
663 	drv_data->dma_rx_data.direction = DMA_DEV_TO_MEM;
664 	drv_data->dma_rx_data.name = "ep93xx-pata-rx";
665 	drv_data->dma_rx_channel = dma_request_channel(mask,
666 		ep93xx_pata_dma_filter, &drv_data->dma_rx_data);
667 	if (!drv_data->dma_rx_channel)
668 		return;
669 
670 	drv_data->dma_tx_data.port = EP93XX_DMA_IDE;
671 	drv_data->dma_tx_data.direction = DMA_MEM_TO_DEV;
672 	drv_data->dma_tx_data.name = "ep93xx-pata-tx";
673 	drv_data->dma_tx_channel = dma_request_channel(mask,
674 		ep93xx_pata_dma_filter, &drv_data->dma_tx_data);
675 	if (!drv_data->dma_tx_channel) {
676 		dma_release_channel(drv_data->dma_rx_channel);
677 		return;
678 	}
679 
680 	/* Configure receive channel direction and source address */
681 	memset(&conf, 0, sizeof(conf));
682 	conf.direction = DMA_DEV_TO_MEM;
683 	conf.src_addr = drv_data->udma_in_phys;
684 	conf.src_addr_width = DMA_SLAVE_BUSWIDTH_4_BYTES;
685 	if (dmaengine_slave_config(drv_data->dma_rx_channel, &conf)) {
686 		dev_err(&pdev->dev, "failed to configure rx dma channel\n");
687 		ep93xx_pata_release_dma(drv_data);
688 		return;
689 	}
690 
691 	/* Configure transmit channel direction and destination address */
692 	memset(&conf, 0, sizeof(conf));
693 	conf.direction = DMA_MEM_TO_DEV;
694 	conf.dst_addr = drv_data->udma_out_phys;
695 	conf.dst_addr_width = DMA_SLAVE_BUSWIDTH_4_BYTES;
696 	if (dmaengine_slave_config(drv_data->dma_tx_channel, &conf)) {
697 		dev_err(&pdev->dev, "failed to configure tx dma channel\n");
698 		ep93xx_pata_release_dma(drv_data);
699 	}
700 }
701 
702 static void ep93xx_pata_dma_start(struct ata_queued_cmd *qc)
703 {
704 	struct dma_async_tx_descriptor *txd;
705 	struct ep93xx_pata_data *drv_data = qc->ap->host->private_data;
706 	void __iomem *base = drv_data->ide_base;
707 	struct ata_device *adev = qc->dev;
708 	u32 v = qc->dma_dir == DMA_TO_DEVICE ? IDEUDMAOP_RWOP : 0;
709 	struct dma_chan *channel = qc->dma_dir == DMA_TO_DEVICE
710 		? drv_data->dma_tx_channel : drv_data->dma_rx_channel;
711 
712 	txd = dmaengine_prep_slave_sg(channel, qc->sg, qc->n_elem, qc->dma_dir,
713 		DMA_CTRL_ACK);
714 	if (!txd) {
715 		dev_err(qc->ap->dev, "failed to prepare slave for sg dma\n");
716 		return;
717 	}
718 	txd->callback = NULL;
719 	txd->callback_param = NULL;
720 
721 	if (dmaengine_submit(txd) < 0) {
722 		dev_err(qc->ap->dev, "failed to submit dma transfer\n");
723 		return;
724 	}
725 	dma_async_issue_pending(channel);
726 
727 	/*
728 	 * When enabling UDMA operation, IDEUDMAOP register needs to be
729 	 * programmed in three step sequence:
730 	 * 1) set or clear the RWOP bit,
731 	 * 2) perform dummy read of the register,
732 	 * 3) set the UEN bit.
733 	 */
734 	writel(v, base + IDEUDMAOP);
735 	readl(base + IDEUDMAOP);
736 	writel(v | IDEUDMAOP_UEN, base + IDEUDMAOP);
737 
738 	writel(IDECFG_IDEEN | IDECFG_UDMA |
739 		((adev->xfer_mode - XFER_UDMA_0) << IDECFG_MODE_SHIFT),
740 		base + IDECFG);
741 }
742 
743 static void ep93xx_pata_dma_stop(struct ata_queued_cmd *qc)
744 {
745 	struct ep93xx_pata_data *drv_data = qc->ap->host->private_data;
746 	void __iomem *base = drv_data->ide_base;
747 
748 	/* terminate all dma transfers, if not yet finished */
749 	dmaengine_terminate_all(drv_data->dma_rx_channel);
750 	dmaengine_terminate_all(drv_data->dma_tx_channel);
751 
752 	/*
753 	 * To properly stop IDE-DMA, IDEUDMAOP register must to be cleared
754 	 * and IDECTRL register must be set to default value.
755 	 */
756 	writel(0, base + IDEUDMAOP);
757 	writel(readl(base + IDECTRL) | IDECTRL_DIOWN | IDECTRL_DIORN |
758 		IDECTRL_CS0N | IDECTRL_CS1N, base + IDECTRL);
759 
760 	ep93xx_pata_enable_pio(drv_data->ide_base,
761 		qc->dev->pio_mode - XFER_PIO_0);
762 
763 	ata_sff_dma_pause(qc->ap);
764 }
765 
766 static void ep93xx_pata_dma_setup(struct ata_queued_cmd *qc)
767 {
768 	qc->ap->ops->sff_exec_command(qc->ap, &qc->tf);
769 }
770 
771 static u8 ep93xx_pata_dma_status(struct ata_port *ap)
772 {
773 	struct ep93xx_pata_data *drv_data = ap->host->private_data;
774 	u32 val = readl(drv_data->ide_base + IDEUDMASTS);
775 
776 	/*
777 	 * UDMA Status Register bits:
778 	 *
779 	 * DMAIDE - DMA request signal from UDMA state machine,
780 	 * INTIDE - INT line generated by UDMA because of errors in the
781 	 *          state machine,
782 	 * SBUSY - UDMA state machine busy, not in idle state,
783 	 * NDO   - error for data-out not completed,
784 	 * NDI   - error for data-in not completed,
785 	 * N4X   - error for data transferred not multiplies of four
786 	 *         32-bit words.
787 	 * (EP93xx UG p27-17)
788 	 */
789 	if (val & IDEUDMASTS_NDO || val & IDEUDMASTS_NDI ||
790 	    val & IDEUDMASTS_N4X || val & IDEUDMASTS_INTIDE)
791 		return ATA_DMA_ERR;
792 
793 	/* read INTRQ (INT[3]) pin input state */
794 	if (readl(drv_data->ide_base + IDECTRL) & IDECTRL_INTRQ)
795 		return ATA_DMA_INTR;
796 
797 	if (val & IDEUDMASTS_SBUSY || val & IDEUDMASTS_DMAIDE)
798 		return ATA_DMA_ACTIVE;
799 
800 	return 0;
801 }
802 
803 /* Note: original code is ata_sff_softreset */
804 static int ep93xx_pata_softreset(struct ata_link *al, unsigned int *classes,
805 				 unsigned long deadline)
806 {
807 	struct ata_port *ap = al->ap;
808 	unsigned int slave_possible = ap->flags & ATA_FLAG_SLAVE_POSS;
809 	unsigned int devmask = 0;
810 	int rc;
811 	u8 err;
812 
813 	/* determine if device 0/1 are present */
814 	if (ep93xx_pata_device_is_present(ap, 0))
815 		devmask |= (1 << 0);
816 	if (slave_possible && ep93xx_pata_device_is_present(ap, 1))
817 		devmask |= (1 << 1);
818 
819 	/* select device 0 again */
820 	ap->ops->sff_dev_select(al->ap, 0);
821 
822 	/* issue bus reset */
823 	rc = ep93xx_pata_bus_softreset(ap, devmask, deadline);
824 	/* if link is ocuppied, -ENODEV too is an error */
825 	if (rc && (rc != -ENODEV || sata_scr_valid(al))) {
826 		ata_link_err(al, "SRST failed (errno=%d)\n", rc);
827 		return rc;
828 	}
829 
830 	/* determine by signature whether we have ATA or ATAPI devices */
831 	classes[0] = ata_sff_dev_classify(&al->device[0], devmask & (1 << 0),
832 					  &err);
833 	if (slave_possible && err != 0x81)
834 		classes[1] = ata_sff_dev_classify(&al->device[1],
835 						  devmask & (1 << 1), &err);
836 
837 	return 0;
838 }
839 
840 /* Note: original code is ata_sff_drain_fifo */
841 static void ep93xx_pata_drain_fifo(struct ata_queued_cmd *qc)
842 {
843 	int count;
844 	struct ata_port *ap;
845 	struct ep93xx_pata_data *drv_data;
846 
847 	/* We only need to flush incoming data when a command was running */
848 	if (qc == NULL || qc->dma_dir == DMA_TO_DEVICE)
849 		return;
850 
851 	ap = qc->ap;
852 	drv_data = ap->host->private_data;
853 	/* Drain up to 64K of data before we give up this recovery method */
854 	for (count = 0; (ap->ops->sff_check_status(ap) & ATA_DRQ)
855 		     && count < 65536; count += 2)
856 		ep93xx_pata_read_reg(drv_data, IDECTRL_ADDR_DATA);
857 
858 	if (count)
859 		ata_port_dbg(ap, "drained %d bytes to clear DRQ.\n", count);
860 
861 }
862 
863 static int ep93xx_pata_port_start(struct ata_port *ap)
864 {
865 	struct ep93xx_pata_data *drv_data = ap->host->private_data;
866 
867 	/*
868 	 * Set timings to safe values at startup (= number of ns from ATA
869 	 * specification), we'll switch to properly calculated values later.
870 	 */
871 	drv_data->t = *ata_timing_find_mode(XFER_PIO_0);
872 	return 0;
873 }
874 
875 static struct scsi_host_template ep93xx_pata_sht = {
876 	ATA_BASE_SHT(DRV_NAME),
877 	/* ep93xx dma implementation limit */
878 	.sg_tablesize		= 32,
879 	/* ep93xx dma can't transfer 65536 bytes at once */
880 	.dma_boundary		= 0x7fff,
881 };
882 
883 static struct ata_port_operations ep93xx_pata_port_ops = {
884 	.inherits		= &ata_bmdma_port_ops,
885 
886 	.qc_prep		= ata_noop_qc_prep,
887 
888 	.softreset		= ep93xx_pata_softreset,
889 	.hardreset		= ATA_OP_NULL,
890 
891 	.sff_dev_select		= ep93xx_pata_dev_select,
892 	.sff_set_devctl		= ep93xx_pata_set_devctl,
893 	.sff_check_status	= ep93xx_pata_check_status,
894 	.sff_check_altstatus	= ep93xx_pata_check_altstatus,
895 	.sff_tf_load		= ep93xx_pata_tf_load,
896 	.sff_tf_read		= ep93xx_pata_tf_read,
897 	.sff_exec_command	= ep93xx_pata_exec_command,
898 	.sff_data_xfer		= ep93xx_pata_data_xfer,
899 	.sff_drain_fifo		= ep93xx_pata_drain_fifo,
900 	.sff_irq_clear		= ATA_OP_NULL,
901 
902 	.set_piomode		= ep93xx_pata_set_piomode,
903 
904 	.bmdma_setup		= ep93xx_pata_dma_setup,
905 	.bmdma_start		= ep93xx_pata_dma_start,
906 	.bmdma_stop		= ep93xx_pata_dma_stop,
907 	.bmdma_status		= ep93xx_pata_dma_status,
908 
909 	.cable_detect		= ata_cable_unknown,
910 	.port_start		= ep93xx_pata_port_start,
911 };
912 
913 static int ep93xx_pata_probe(struct platform_device *pdev)
914 {
915 	struct ep93xx_pata_data *drv_data;
916 	struct ata_host *host;
917 	struct ata_port *ap;
918 	int irq;
919 	struct resource *mem_res;
920 	void __iomem *ide_base;
921 	int err;
922 
923 	err = ep93xx_ide_acquire_gpio(pdev);
924 	if (err)
925 		return err;
926 
927 	/* INT[3] (IRQ_EP93XX_EXT3) line connected as pull down */
928 	irq = platform_get_irq(pdev, 0);
929 	if (irq < 0) {
930 		err = irq;
931 		goto err_rel_gpio;
932 	}
933 
934 	mem_res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
935 	ide_base = devm_ioremap_resource(&pdev->dev, mem_res);
936 	if (IS_ERR(ide_base)) {
937 		err = PTR_ERR(ide_base);
938 		goto err_rel_gpio;
939 	}
940 
941 	drv_data = devm_kzalloc(&pdev->dev, sizeof(*drv_data), GFP_KERNEL);
942 	if (!drv_data) {
943 		err = -ENXIO;
944 		goto err_rel_gpio;
945 	}
946 
947 	drv_data->pdev = pdev;
948 	drv_data->ide_base = ide_base;
949 	drv_data->udma_in_phys = mem_res->start + IDEUDMADATAIN;
950 	drv_data->udma_out_phys = mem_res->start + IDEUDMADATAOUT;
951 	ep93xx_pata_dma_init(drv_data);
952 
953 	/* allocate host */
954 	host = ata_host_alloc(&pdev->dev, 1);
955 	if (!host) {
956 		err = -ENXIO;
957 		goto err_rel_dma;
958 	}
959 
960 	ep93xx_pata_clear_regs(ide_base);
961 
962 	host->private_data = drv_data;
963 
964 	ap = host->ports[0];
965 	ap->dev = &pdev->dev;
966 	ap->ops = &ep93xx_pata_port_ops;
967 	ap->flags |= ATA_FLAG_SLAVE_POSS;
968 	ap->pio_mask = ATA_PIO4;
969 
970 	/*
971 	 * Maximum UDMA modes:
972 	 * EP931x rev.E0 - UDMA2
973 	 * EP931x rev.E1 - UDMA3
974 	 * EP931x rev.E2 - UDMA4
975 	 *
976 	 * MWDMA support was removed from EP931x rev.E2,
977 	 * so this driver supports only UDMA modes.
978 	 */
979 	if (drv_data->dma_rx_channel && drv_data->dma_tx_channel) {
980 		int chip_rev = ep93xx_chip_revision();
981 
982 		if (chip_rev == EP93XX_CHIP_REV_E1)
983 			ap->udma_mask = ATA_UDMA3;
984 		else if (chip_rev == EP93XX_CHIP_REV_E2)
985 			ap->udma_mask = ATA_UDMA4;
986 		else
987 			ap->udma_mask = ATA_UDMA2;
988 	}
989 
990 	/* defaults, pio 0 */
991 	ep93xx_pata_enable_pio(ide_base, 0);
992 
993 	dev_info(&pdev->dev, "version " DRV_VERSION "\n");
994 
995 	/* activate host */
996 	err = ata_host_activate(host, irq, ata_bmdma_interrupt, 0,
997 		&ep93xx_pata_sht);
998 	if (err == 0)
999 		return 0;
1000 
1001 err_rel_dma:
1002 	ep93xx_pata_release_dma(drv_data);
1003 err_rel_gpio:
1004 	ep93xx_ide_release_gpio(pdev);
1005 	return err;
1006 }
1007 
1008 static int ep93xx_pata_remove(struct platform_device *pdev)
1009 {
1010 	struct ata_host *host = platform_get_drvdata(pdev);
1011 	struct ep93xx_pata_data *drv_data = host->private_data;
1012 
1013 	ata_host_detach(host);
1014 	ep93xx_pata_release_dma(drv_data);
1015 	ep93xx_pata_clear_regs(drv_data->ide_base);
1016 	ep93xx_ide_release_gpio(pdev);
1017 	return 0;
1018 }
1019 
1020 static struct platform_driver ep93xx_pata_platform_driver = {
1021 	.driver = {
1022 		.name = DRV_NAME,
1023 	},
1024 	.probe = ep93xx_pata_probe,
1025 	.remove = ep93xx_pata_remove,
1026 };
1027 
1028 module_platform_driver(ep93xx_pata_platform_driver);
1029 
1030 MODULE_AUTHOR("Alessandro Zummo, Lennert Buytenhek, Joao Ramos, "
1031 		"Bartlomiej Zolnierkiewicz, Rafal Prylowski");
1032 MODULE_DESCRIPTION("low-level driver for cirrus ep93xx IDE controller");
1033 MODULE_LICENSE("GPL");
1034 MODULE_VERSION(DRV_VERSION);
1035 MODULE_ALIAS("platform:pata_ep93xx");
1036