xref: /linux/drivers/ata/pata_ep93xx.c (revision c7fdfd2bee1cf1448e5244da1a734e680f634b02)
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 #include <linux/mod_devicetable.h>
48 
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 	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 dma_chan *dma_tx_channel;
139 };
140 
141 static void ep93xx_pata_clear_regs(void __iomem *base)
142 {
143 	writel(IDECTRL_CS0N | IDECTRL_CS1N | IDECTRL_DIORN |
144 		IDECTRL_DIOWN, base + IDECTRL);
145 
146 	writel(0, base + IDECFG);
147 	writel(0, base + IDEMDMAOP);
148 	writel(0, base + IDEUDMAOP);
149 	writel(0, base + IDEDATAOUT);
150 	writel(0, base + IDEDATAIN);
151 	writel(0, base + IDEMDMADATAOUT);
152 	writel(0, base + IDEMDMADATAIN);
153 	writel(0, base + IDEUDMADATAOUT);
154 	writel(0, base + IDEUDMADATAIN);
155 	writel(0, base + IDEUDMADEBUG);
156 }
157 
158 static bool ep93xx_pata_check_iordy(void __iomem *base)
159 {
160 	return !!(readl(base + IDECTRL) & IDECTRL_IORDY);
161 }
162 
163 /*
164  * According to EP93xx User's Guide, WST field of IDECFG specifies number
165  * of HCLK cycles to hold the data bus after a PIO write operation.
166  * It should be programmed to guarantee following delays:
167  *
168  * PIO Mode   [ns]
169  * 0          30
170  * 1          20
171  * 2          15
172  * 3          10
173  * 4          5
174  *
175  * Maximum possible value for HCLK is 100MHz.
176  */
177 static int ep93xx_pata_get_wst(int pio_mode)
178 {
179 	int val;
180 
181 	if (pio_mode == 0)
182 		val = 3;
183 	else if (pio_mode < 3)
184 		val = 2;
185 	else
186 		val = 1;
187 
188 	return val << IDECFG_WST_SHIFT;
189 }
190 
191 static void ep93xx_pata_enable_pio(void __iomem *base, int pio_mode)
192 {
193 	writel(IDECFG_IDEEN | IDECFG_PIO |
194 		ep93xx_pata_get_wst(pio_mode) |
195 		(pio_mode << IDECFG_MODE_SHIFT), base + IDECFG);
196 }
197 
198 /*
199  * Based on delay loop found in mach-pxa/mp900.c.
200  *
201  * Single iteration should take 5 cpu cycles. This is 25ns assuming the
202  * fastest ep93xx cpu speed (200MHz) and is better optimized for PIO4 timings
203  * than eg. 20ns.
204  */
205 static void ep93xx_pata_delay(unsigned long count)
206 {
207 #ifdef CONFIG_ARM
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 #else
217 	while (count--)
218 		cpu_relax();
219 #endif
220 }
221 
222 static unsigned long ep93xx_pata_wait_for_iordy(void __iomem *base,
223 						unsigned long t2)
224 {
225 	/*
226 	 * According to ATA specification, IORDY pin can be first sampled
227 	 * tA = 35ns after activation of DIOR-/DIOW-. Maximum IORDY pulse
228 	 * width is tB = 1250ns.
229 	 *
230 	 * We are already t2 delay loop iterations after activation of
231 	 * DIOR-/DIOW-, so we set timeout to (1250 + 35) / 25 - t2 additional
232 	 * delay loop iterations.
233 	 */
234 	unsigned long start = (1250 + 35) / 25 - t2;
235 	unsigned long counter = start;
236 
237 	while (!ep93xx_pata_check_iordy(base) && counter--)
238 		ep93xx_pata_delay(1);
239 	return start - counter;
240 }
241 
242 /* common part at start of ep93xx_pata_read/write() */
243 static void ep93xx_pata_rw_begin(void __iomem *base, unsigned long addr,
244 				 unsigned long t1)
245 {
246 	writel(IDECTRL_DIOWN | IDECTRL_DIORN | addr, base + IDECTRL);
247 	ep93xx_pata_delay(t1);
248 }
249 
250 /* common part at end of ep93xx_pata_read/write() */
251 static void ep93xx_pata_rw_end(void __iomem *base, unsigned long addr,
252 			       bool iordy, unsigned long t0, unsigned long t2,
253 			       unsigned long t2i)
254 {
255 	ep93xx_pata_delay(t2);
256 	/* lengthen t2 if needed */
257 	if (iordy)
258 		t2 += ep93xx_pata_wait_for_iordy(base, t2);
259 	writel(IDECTRL_DIOWN | IDECTRL_DIORN | addr, base + IDECTRL);
260 	if (t0 > t2 && t0 - t2 > t2i)
261 		ep93xx_pata_delay(t0 - t2);
262 	else
263 		ep93xx_pata_delay(t2i);
264 }
265 
266 static u16 ep93xx_pata_read(struct ep93xx_pata_data *drv_data,
267 			    unsigned long addr,
268 			    bool reg)
269 {
270 	void __iomem *base = drv_data->ide_base;
271 	const struct ata_timing *t = &drv_data->t;
272 	unsigned long t0 = reg ? t->cyc8b : t->cycle;
273 	unsigned long t2 = reg ? t->act8b : t->active;
274 	unsigned long t2i = reg ? t->rec8b : t->recover;
275 
276 	ep93xx_pata_rw_begin(base, addr, t->setup);
277 	writel(IDECTRL_DIOWN | addr, base + IDECTRL);
278 	/*
279 	 * The IDEDATAIN register is loaded from the DD pins at the positive
280 	 * edge of the DIORN signal. (EP93xx UG p27-14)
281 	 */
282 	ep93xx_pata_rw_end(base, addr, drv_data->iordy, t0, t2, t2i);
283 	return readl(base + IDEDATAIN);
284 }
285 
286 /* IDE register read */
287 static u16 ep93xx_pata_read_reg(struct ep93xx_pata_data *drv_data,
288 				unsigned long addr)
289 {
290 	return ep93xx_pata_read(drv_data, addr, true);
291 }
292 
293 /* PIO data read */
294 static u16 ep93xx_pata_read_data(struct ep93xx_pata_data *drv_data,
295 				 unsigned long addr)
296 {
297 	return ep93xx_pata_read(drv_data, addr, false);
298 }
299 
300 static void ep93xx_pata_write(struct ep93xx_pata_data *drv_data,
301 			      u16 value, unsigned long addr,
302 			      bool reg)
303 {
304 	void __iomem *base = drv_data->ide_base;
305 	const struct ata_timing *t = &drv_data->t;
306 	unsigned long t0 = reg ? t->cyc8b : t->cycle;
307 	unsigned long t2 = reg ? t->act8b : t->active;
308 	unsigned long t2i = reg ? t->rec8b : t->recover;
309 
310 	ep93xx_pata_rw_begin(base, addr, t->setup);
311 	/*
312 	 * Value from IDEDATAOUT register is driven onto the DD pins when
313 	 * DIOWN is low. (EP93xx UG p27-13)
314 	 */
315 	writel(value, base + IDEDATAOUT);
316 	writel(IDECTRL_DIORN | addr, base + IDECTRL);
317 	ep93xx_pata_rw_end(base, addr, drv_data->iordy, t0, t2, t2i);
318 }
319 
320 /* IDE register write */
321 static void ep93xx_pata_write_reg(struct ep93xx_pata_data *drv_data,
322 				  u16 value, unsigned long addr)
323 {
324 	ep93xx_pata_write(drv_data, value, addr, true);
325 }
326 
327 /* PIO data write */
328 static void ep93xx_pata_write_data(struct ep93xx_pata_data *drv_data,
329 				   u16 value, unsigned long addr)
330 {
331 	ep93xx_pata_write(drv_data, value, addr, false);
332 }
333 
334 static void ep93xx_pata_set_piomode(struct ata_port *ap,
335 				    struct ata_device *adev)
336 {
337 	struct ep93xx_pata_data *drv_data = ap->host->private_data;
338 	struct ata_device *pair = ata_dev_pair(adev);
339 	/*
340 	 * Calculate timings for the delay loop, assuming ep93xx cpu speed
341 	 * is 200MHz (maximum possible for ep93xx). If actual cpu speed is
342 	 * slower, we will wait a bit longer in each delay.
343 	 * Additional division of cpu speed by 5, because single iteration
344 	 * of our delay loop takes 5 cpu cycles (25ns).
345 	 */
346 	unsigned long T = 1000000 / (200 / 5);
347 
348 	ata_timing_compute(adev, adev->pio_mode, &drv_data->t, T, 0);
349 	if (pair && pair->pio_mode) {
350 		struct ata_timing t;
351 		ata_timing_compute(pair, pair->pio_mode, &t, T, 0);
352 		ata_timing_merge(&t, &drv_data->t, &drv_data->t,
353 			ATA_TIMING_SETUP | ATA_TIMING_8BIT);
354 	}
355 	drv_data->iordy = ata_pio_need_iordy(adev);
356 
357 	ep93xx_pata_enable_pio(drv_data->ide_base,
358 			       adev->pio_mode - XFER_PIO_0);
359 }
360 
361 /* Note: original code is ata_sff_check_status */
362 static u8 ep93xx_pata_check_status(struct ata_port *ap)
363 {
364 	struct ep93xx_pata_data *drv_data = ap->host->private_data;
365 
366 	return ep93xx_pata_read_reg(drv_data, IDECTRL_ADDR_STATUS);
367 }
368 
369 static u8 ep93xx_pata_check_altstatus(struct ata_port *ap)
370 {
371 	struct ep93xx_pata_data *drv_data = ap->host->private_data;
372 
373 	return ep93xx_pata_read_reg(drv_data, IDECTRL_ADDR_ALTSTATUS);
374 }
375 
376 /* Note: original code is ata_sff_tf_load */
377 static void ep93xx_pata_tf_load(struct ata_port *ap,
378 				const struct ata_taskfile *tf)
379 {
380 	struct ep93xx_pata_data *drv_data = ap->host->private_data;
381 	unsigned int is_addr = tf->flags & ATA_TFLAG_ISADDR;
382 
383 	if (tf->ctl != ap->last_ctl) {
384 		ep93xx_pata_write_reg(drv_data, tf->ctl, IDECTRL_ADDR_CTL);
385 		ap->last_ctl = tf->ctl;
386 		ata_wait_idle(ap);
387 	}
388 
389 	if (is_addr && (tf->flags & ATA_TFLAG_LBA48)) {
390 		ep93xx_pata_write_reg(drv_data, tf->hob_feature,
391 			IDECTRL_ADDR_FEATURE);
392 		ep93xx_pata_write_reg(drv_data, tf->hob_nsect,
393 			IDECTRL_ADDR_NSECT);
394 		ep93xx_pata_write_reg(drv_data, tf->hob_lbal,
395 			IDECTRL_ADDR_LBAL);
396 		ep93xx_pata_write_reg(drv_data, tf->hob_lbam,
397 			IDECTRL_ADDR_LBAM);
398 		ep93xx_pata_write_reg(drv_data, tf->hob_lbah,
399 			IDECTRL_ADDR_LBAH);
400 	}
401 
402 	if (is_addr) {
403 		ep93xx_pata_write_reg(drv_data, tf->feature,
404 			IDECTRL_ADDR_FEATURE);
405 		ep93xx_pata_write_reg(drv_data, tf->nsect, IDECTRL_ADDR_NSECT);
406 		ep93xx_pata_write_reg(drv_data, tf->lbal, IDECTRL_ADDR_LBAL);
407 		ep93xx_pata_write_reg(drv_data, tf->lbam, IDECTRL_ADDR_LBAM);
408 		ep93xx_pata_write_reg(drv_data, tf->lbah, IDECTRL_ADDR_LBAH);
409 	}
410 
411 	if (tf->flags & ATA_TFLAG_DEVICE)
412 		ep93xx_pata_write_reg(drv_data, tf->device,
413 			IDECTRL_ADDR_DEVICE);
414 
415 	ata_wait_idle(ap);
416 }
417 
418 /* Note: original code is ata_sff_tf_read */
419 static void ep93xx_pata_tf_read(struct ata_port *ap, struct ata_taskfile *tf)
420 {
421 	struct ep93xx_pata_data *drv_data = ap->host->private_data;
422 
423 	tf->status = ep93xx_pata_check_status(ap);
424 	tf->error = ep93xx_pata_read_reg(drv_data, IDECTRL_ADDR_FEATURE);
425 	tf->nsect = ep93xx_pata_read_reg(drv_data, IDECTRL_ADDR_NSECT);
426 	tf->lbal = ep93xx_pata_read_reg(drv_data, IDECTRL_ADDR_LBAL);
427 	tf->lbam = ep93xx_pata_read_reg(drv_data, IDECTRL_ADDR_LBAM);
428 	tf->lbah = ep93xx_pata_read_reg(drv_data, IDECTRL_ADDR_LBAH);
429 	tf->device = ep93xx_pata_read_reg(drv_data, IDECTRL_ADDR_DEVICE);
430 
431 	if (tf->flags & ATA_TFLAG_LBA48) {
432 		ep93xx_pata_write_reg(drv_data, tf->ctl | ATA_HOB,
433 			IDECTRL_ADDR_CTL);
434 		tf->hob_feature = ep93xx_pata_read_reg(drv_data,
435 			IDECTRL_ADDR_FEATURE);
436 		tf->hob_nsect = ep93xx_pata_read_reg(drv_data,
437 			IDECTRL_ADDR_NSECT);
438 		tf->hob_lbal = ep93xx_pata_read_reg(drv_data,
439 			IDECTRL_ADDR_LBAL);
440 		tf->hob_lbam = ep93xx_pata_read_reg(drv_data,
441 			IDECTRL_ADDR_LBAM);
442 		tf->hob_lbah = ep93xx_pata_read_reg(drv_data,
443 			IDECTRL_ADDR_LBAH);
444 		ep93xx_pata_write_reg(drv_data, tf->ctl, IDECTRL_ADDR_CTL);
445 		ap->last_ctl = tf->ctl;
446 	}
447 }
448 
449 /* Note: original code is ata_sff_exec_command */
450 static void ep93xx_pata_exec_command(struct ata_port *ap,
451 				     const struct ata_taskfile *tf)
452 {
453 	struct ep93xx_pata_data *drv_data = ap->host->private_data;
454 
455 	ep93xx_pata_write_reg(drv_data, tf->command,
456 			  IDECTRL_ADDR_COMMAND);
457 	ata_sff_pause(ap);
458 }
459 
460 /* Note: original code is ata_sff_dev_select */
461 static void ep93xx_pata_dev_select(struct ata_port *ap, unsigned int device)
462 {
463 	struct ep93xx_pata_data *drv_data = ap->host->private_data;
464 	u8 tmp = ATA_DEVICE_OBS;
465 
466 	if (device != 0)
467 		tmp |= ATA_DEV1;
468 
469 	ep93xx_pata_write_reg(drv_data, tmp, IDECTRL_ADDR_DEVICE);
470 	ata_sff_pause(ap);	/* needed; also flushes, for mmio */
471 }
472 
473 /* Note: original code is ata_sff_set_devctl */
474 static void ep93xx_pata_set_devctl(struct ata_port *ap, u8 ctl)
475 {
476 	struct ep93xx_pata_data *drv_data = ap->host->private_data;
477 
478 	ep93xx_pata_write_reg(drv_data, ctl, IDECTRL_ADDR_CTL);
479 }
480 
481 /* Note: original code is ata_sff_data_xfer */
482 static unsigned int ep93xx_pata_data_xfer(struct ata_queued_cmd *qc,
483 					  unsigned char *buf,
484 					  unsigned int buflen, int rw)
485 {
486 	struct ata_port *ap = qc->dev->link->ap;
487 	struct ep93xx_pata_data *drv_data = ap->host->private_data;
488 	u16 *data = (u16 *)buf;
489 	unsigned int words = buflen >> 1;
490 
491 	/* Transfer multiple of 2 bytes */
492 	while (words--)
493 		if (rw == READ)
494 			*data++ = cpu_to_le16(
495 				ep93xx_pata_read_data(
496 					drv_data, IDECTRL_ADDR_DATA));
497 		else
498 			ep93xx_pata_write_data(drv_data, le16_to_cpu(*data++),
499 				IDECTRL_ADDR_DATA);
500 
501 	/* Transfer trailing 1 byte, if any. */
502 	if (unlikely(buflen & 0x01)) {
503 		unsigned char pad[2] = { };
504 
505 		buf += buflen - 1;
506 
507 		if (rw == READ) {
508 			*pad = cpu_to_le16(
509 				ep93xx_pata_read_data(
510 					drv_data, IDECTRL_ADDR_DATA));
511 			*buf = pad[0];
512 		} else {
513 			pad[0] = *buf;
514 			ep93xx_pata_write_data(drv_data, le16_to_cpu(*pad),
515 					  IDECTRL_ADDR_DATA);
516 		}
517 		words++;
518 	}
519 
520 	return words << 1;
521 }
522 
523 /* Note: original code is ata_devchk */
524 static bool ep93xx_pata_device_is_present(struct ata_port *ap,
525 					  unsigned int device)
526 {
527 	struct ep93xx_pata_data *drv_data = ap->host->private_data;
528 	u8 nsect, lbal;
529 
530 	ap->ops->sff_dev_select(ap, device);
531 
532 	ep93xx_pata_write_reg(drv_data, 0x55, IDECTRL_ADDR_NSECT);
533 	ep93xx_pata_write_reg(drv_data, 0xaa, IDECTRL_ADDR_LBAL);
534 
535 	ep93xx_pata_write_reg(drv_data, 0xaa, IDECTRL_ADDR_NSECT);
536 	ep93xx_pata_write_reg(drv_data, 0x55, IDECTRL_ADDR_LBAL);
537 
538 	ep93xx_pata_write_reg(drv_data, 0x55, IDECTRL_ADDR_NSECT);
539 	ep93xx_pata_write_reg(drv_data, 0xaa, IDECTRL_ADDR_LBAL);
540 
541 	nsect = ep93xx_pata_read_reg(drv_data, IDECTRL_ADDR_NSECT);
542 	lbal = ep93xx_pata_read_reg(drv_data, IDECTRL_ADDR_LBAL);
543 
544 	if ((nsect == 0x55) && (lbal == 0xaa))
545 		return true;
546 
547 	return false;
548 }
549 
550 /* Note: original code is ata_sff_wait_after_reset */
551 static int ep93xx_pata_wait_after_reset(struct ata_link *link,
552 					unsigned int devmask,
553 					unsigned long deadline)
554 {
555 	struct ata_port *ap = link->ap;
556 	struct ep93xx_pata_data *drv_data = ap->host->private_data;
557 	unsigned int dev0 = devmask & (1 << 0);
558 	unsigned int dev1 = devmask & (1 << 1);
559 	int rc, ret = 0;
560 
561 	ata_msleep(ap, ATA_WAIT_AFTER_RESET);
562 
563 	/* always check readiness of the master device */
564 	rc = ata_sff_wait_ready(link, deadline);
565 	/*
566 	 * -ENODEV means the odd clown forgot the D7 pulldown resistor
567 	 * and TF status is 0xff, bail out on it too.
568 	 */
569 	if (rc)
570 		return rc;
571 
572 	/*
573 	 * if device 1 was found in ata_devchk, wait for register
574 	 * access briefly, then wait for BSY to clear.
575 	 */
576 	if (dev1) {
577 		int i;
578 
579 		ap->ops->sff_dev_select(ap, 1);
580 
581 		/*
582 		 * Wait for register access.  Some ATAPI devices fail
583 		 * to set nsect/lbal after reset, so don't waste too
584 		 * much time on it.  We're gonna wait for !BSY anyway.
585 		 */
586 		for (i = 0; i < 2; i++) {
587 			u8 nsect, lbal;
588 
589 			nsect = ep93xx_pata_read_reg(drv_data,
590 				IDECTRL_ADDR_NSECT);
591 			lbal = ep93xx_pata_read_reg(drv_data,
592 				IDECTRL_ADDR_LBAL);
593 			if (nsect == 1 && lbal == 1)
594 				break;
595 			msleep(50);	/* give drive a breather */
596 		}
597 
598 		rc = ata_sff_wait_ready(link, deadline);
599 		if (rc) {
600 			if (rc != -ENODEV)
601 				return rc;
602 			ret = rc;
603 		}
604 	}
605 	/* is all this really necessary? */
606 	ap->ops->sff_dev_select(ap, 0);
607 	if (dev1)
608 		ap->ops->sff_dev_select(ap, 1);
609 	if (dev0)
610 		ap->ops->sff_dev_select(ap, 0);
611 
612 	return ret;
613 }
614 
615 /* Note: original code is ata_bus_softreset */
616 static int ep93xx_pata_bus_softreset(struct ata_port *ap, unsigned int devmask,
617 				     unsigned long deadline)
618 {
619 	struct ep93xx_pata_data *drv_data = ap->host->private_data;
620 
621 	ep93xx_pata_write_reg(drv_data, ap->ctl, IDECTRL_ADDR_CTL);
622 	udelay(20);		/* FIXME: flush */
623 	ep93xx_pata_write_reg(drv_data, ap->ctl | ATA_SRST, IDECTRL_ADDR_CTL);
624 	udelay(20);		/* FIXME: flush */
625 	ep93xx_pata_write_reg(drv_data, ap->ctl, IDECTRL_ADDR_CTL);
626 	ap->last_ctl = ap->ctl;
627 
628 	return ep93xx_pata_wait_after_reset(&ap->link, devmask, deadline);
629 }
630 
631 static void ep93xx_pata_release_dma(struct ep93xx_pata_data *drv_data)
632 {
633 	if (drv_data->dma_rx_channel) {
634 		dma_release_channel(drv_data->dma_rx_channel);
635 		drv_data->dma_rx_channel = NULL;
636 	}
637 	if (drv_data->dma_tx_channel) {
638 		dma_release_channel(drv_data->dma_tx_channel);
639 		drv_data->dma_tx_channel = NULL;
640 	}
641 }
642 
643 static int ep93xx_pata_dma_init(struct ep93xx_pata_data *drv_data)
644 {
645 	struct platform_device *pdev = drv_data->pdev;
646 	struct device *dev = &pdev->dev;
647 	dma_cap_mask_t mask;
648 	struct dma_slave_config conf;
649 	int ret;
650 
651 	dma_cap_zero(mask);
652 	dma_cap_set(DMA_SLAVE, mask);
653 
654 	/*
655 	 * Request two channels for IDE. Another possibility would be
656 	 * to request only one channel, and reprogram it's direction at
657 	 * start of new transfer.
658 	 */
659 	drv_data->dma_rx_channel = dma_request_chan(dev, "rx");
660 	if (IS_ERR(drv_data->dma_rx_channel))
661 		return dev_err_probe(dev, PTR_ERR(drv_data->dma_rx_channel),
662 				     "rx DMA setup failed\n");
663 
664 	drv_data->dma_tx_channel = dma_request_chan(&pdev->dev, "tx");
665 	if (IS_ERR(drv_data->dma_tx_channel)) {
666 		ret = dev_err_probe(dev, PTR_ERR(drv_data->dma_tx_channel),
667 				    "tx DMA setup failed\n");
668 		goto fail_release_rx;
669 	}
670 
671 	/* Configure receive channel direction and source address */
672 	memset(&conf, 0, sizeof(conf));
673 	conf.direction = DMA_DEV_TO_MEM;
674 	conf.src_addr = drv_data->udma_in_phys;
675 	conf.src_addr_width = DMA_SLAVE_BUSWIDTH_4_BYTES;
676 	ret = dmaengine_slave_config(drv_data->dma_rx_channel, &conf);
677 	if (ret) {
678 		dev_err_probe(dev, ret, "failed to configure rx dma channel");
679 		goto fail_release_dma;
680 	}
681 
682 	/* Configure transmit channel direction and destination address */
683 	memset(&conf, 0, sizeof(conf));
684 	conf.direction = DMA_MEM_TO_DEV;
685 	conf.dst_addr = drv_data->udma_out_phys;
686 	conf.dst_addr_width = DMA_SLAVE_BUSWIDTH_4_BYTES;
687 	ret = dmaengine_slave_config(drv_data->dma_tx_channel, &conf);
688 	if (ret) {
689 		dev_err_probe(dev, ret, "failed to configure tx dma channel");
690 		goto fail_release_dma;
691 	}
692 
693 	return 0;
694 
695 fail_release_rx:
696 	dma_release_channel(drv_data->dma_rx_channel);
697 fail_release_dma:
698 	ep93xx_pata_release_dma(drv_data);
699 
700 	return ret;
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 	.reset.softreset	= ep93xx_pata_softreset,
888 	.reset.hardreset	= ATA_OP_NULL,
889 
890 	.sff_dev_select		= ep93xx_pata_dev_select,
891 	.sff_set_devctl		= ep93xx_pata_set_devctl,
892 	.sff_check_status	= ep93xx_pata_check_status,
893 	.sff_check_altstatus	= ep93xx_pata_check_altstatus,
894 	.sff_tf_load		= ep93xx_pata_tf_load,
895 	.sff_tf_read		= ep93xx_pata_tf_read,
896 	.sff_exec_command	= ep93xx_pata_exec_command,
897 	.sff_data_xfer		= ep93xx_pata_data_xfer,
898 	.sff_drain_fifo		= ep93xx_pata_drain_fifo,
899 	.sff_irq_clear		= ATA_OP_NULL,
900 
901 	.set_piomode		= ep93xx_pata_set_piomode,
902 
903 	.bmdma_setup		= ep93xx_pata_dma_setup,
904 	.bmdma_start		= ep93xx_pata_dma_start,
905 	.bmdma_stop		= ep93xx_pata_dma_stop,
906 	.bmdma_status		= ep93xx_pata_dma_status,
907 
908 	.cable_detect		= ata_cable_unknown,
909 	.port_start		= ep93xx_pata_port_start,
910 };
911 
912 static const struct soc_device_attribute ep93xx_soc_table[] = {
913 	{ .revision = "E1", .data = (void *)ATA_UDMA3 },
914 	{ .revision = "E2", .data = (void *)ATA_UDMA4 },
915 	{ /* sentinel */ }
916 };
917 
918 static int ep93xx_pata_probe(struct platform_device *pdev)
919 {
920 	struct ep93xx_pata_data *drv_data;
921 	struct ata_host *host;
922 	struct ata_port *ap;
923 	int irq;
924 	struct resource *mem_res;
925 	void __iomem *ide_base;
926 	int err;
927 
928 	/* INT[3] (IRQ_EP93XX_EXT3) line connected as pull down */
929 	irq = platform_get_irq(pdev, 0);
930 	if (irq < 0)
931 		return irq;
932 
933 	ide_base = devm_platform_get_and_ioremap_resource(pdev, 0, &mem_res);
934 	if (IS_ERR(ide_base))
935 		return PTR_ERR(ide_base);
936 
937 	drv_data = devm_kzalloc(&pdev->dev, sizeof(*drv_data), GFP_KERNEL);
938 	if (!drv_data)
939 		return -ENOMEM;
940 
941 	drv_data->pdev = pdev;
942 	drv_data->ide_base = ide_base;
943 	drv_data->udma_in_phys = mem_res->start + IDEUDMADATAIN;
944 	drv_data->udma_out_phys = mem_res->start + IDEUDMADATAOUT;
945 	err = ep93xx_pata_dma_init(drv_data);
946 	if (err)
947 		return err;
948 
949 	/* allocate host */
950 	host = ata_host_alloc(&pdev->dev, 1);
951 	if (!host) {
952 		err = -ENOMEM;
953 		goto err_rel_dma;
954 	}
955 
956 	ep93xx_pata_clear_regs(ide_base);
957 
958 	host->private_data = drv_data;
959 
960 	ap = host->ports[0];
961 	ap->dev = &pdev->dev;
962 	ap->ops = &ep93xx_pata_port_ops;
963 	ap->flags |= ATA_FLAG_SLAVE_POSS;
964 	ap->pio_mask = ATA_PIO4;
965 
966 	/*
967 	 * Maximum UDMA modes:
968 	 * EP931x rev.E0 - UDMA2
969 	 * EP931x rev.E1 - UDMA3
970 	 * EP931x rev.E2 - UDMA4
971 	 *
972 	 * MWDMA support was removed from EP931x rev.E2,
973 	 * so this driver supports only UDMA modes.
974 	 */
975 	if (drv_data->dma_rx_channel && drv_data->dma_tx_channel) {
976 		const struct soc_device_attribute *match;
977 
978 		match = soc_device_match(ep93xx_soc_table);
979 		if (match)
980 			ap->udma_mask = (unsigned long) match->data;
981 		else
982 			ap->udma_mask = ATA_UDMA2;
983 	}
984 
985 	/* defaults, pio 0 */
986 	ep93xx_pata_enable_pio(ide_base, 0);
987 
988 	dev_info(&pdev->dev, "version " DRV_VERSION "\n");
989 
990 	/* activate host */
991 	err = ata_host_activate(host, irq, ata_bmdma_interrupt, 0,
992 		&ep93xx_pata_sht);
993 	if (err == 0)
994 		return 0;
995 
996 err_rel_dma:
997 	ep93xx_pata_release_dma(drv_data);
998 	return err;
999 }
1000 
1001 static void ep93xx_pata_remove(struct platform_device *pdev)
1002 {
1003 	struct ata_host *host = platform_get_drvdata(pdev);
1004 	struct ep93xx_pata_data *drv_data = host->private_data;
1005 
1006 	ata_host_detach(host);
1007 	ep93xx_pata_release_dma(drv_data);
1008 	ep93xx_pata_clear_regs(drv_data->ide_base);
1009 }
1010 
1011 static const struct of_device_id ep93xx_pata_of_ids[] = {
1012 	{ .compatible = "cirrus,ep9312-pata" },
1013 	{ /* sentinel */ }
1014 };
1015 MODULE_DEVICE_TABLE(of, ep93xx_pata_of_ids);
1016 
1017 static struct platform_driver ep93xx_pata_platform_driver = {
1018 	.driver = {
1019 		.name = DRV_NAME,
1020 		.of_match_table = ep93xx_pata_of_ids,
1021 	},
1022 	.probe = ep93xx_pata_probe,
1023 	.remove = ep93xx_pata_remove,
1024 };
1025 
1026 module_platform_driver(ep93xx_pata_platform_driver);
1027 
1028 MODULE_AUTHOR("Alessandro Zummo, Lennert Buytenhek, Joao Ramos, "
1029 		"Bartlomiej Zolnierkiewicz, Rafal Prylowski");
1030 MODULE_DESCRIPTION("low-level driver for cirrus ep93xx IDE controller");
1031 MODULE_LICENSE("GPL");
1032 MODULE_VERSION(DRV_VERSION);
1033 MODULE_ALIAS("platform:pata_ep93xx");
1034