aboutsummaryrefslogtreecommitdiffstats
path: root/drivers/ide/ide-timings.c
blob: c7a65ee72310fcf53c6d0b719b8520f29c51219e (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
/*
 *  Copyright (c) 1999-2001 Vojtech Pavlik
 *  Copyright (c) 2007-2008 Bartlomiej Zolnierkiewicz
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
 *
 * Should you need to contact me, the author, you can do so either by
 * e-mail - mail your message to <vojtech@ucw.cz>, or by paper mail:
 * Vojtech Pavlik, Simunkova 1594, Prague 8, 182 00 Czech Republic
 */

#include <linux/kernel.h>
#include <linux/ide.h>
#include <linux/module.h>

/*
 * PIO 0-5, MWDMA 0-2 and UDMA 0-6 timings (in nanoseconds).
 * These were taken from ATA/ATAPI-6 standard, rev 0a, except
 * for PIO 5, which is a nonstandard extension and UDMA6, which
 * is currently supported only by Maxtor drives.
 */

static struct ide_timing ide_timing[] = {

	{ XFER_UDMA_6,     0,   0,   0,   0,   0,   0,   0,  15 },
	{ XFER_UDMA_5,     0,   0,   0,   0,   0,   0,   0,  20 },
	{ XFER_UDMA_4,     0,   0,   0,   0,   0,   0,   0,  30 },
	{ XFER_UDMA_3,     0,   0,   0,   0,   0,   0,   0,  45 },

	{ XFER_UDMA_2,     0,   0,   0,   0,   0,   0,   0,  60 },
	{ XFER_UDMA_1,     0,   0,   0,   0,   0,   0,   0,  80 },
	{ XFER_UDMA_0,     0,   0,   0,   0,   0,   0,   0, 120 },

	{ XFER_MW_DMA_4,  25,   0,   0,   0,  55,  20,  80,   0 },
	{ XFER_MW_DMA_3,  25,   0,   0,   0,  65,  25, 100,   0 },
	{ XFER_MW_DMA_2,  25,   0,   0,   0,  70,  25, 120,   0 },
	{ XFER_MW_DMA_1,  45,   0,   0,   0,  80,  50, 150,   0 },
	{ XFER_MW_DMA_0,  60,   0,   0,   0, 215, 215, 480,   0 },

	{ XFER_SW_DMA_2,  60,   0,   0,   0, 120, 120, 240,   0 },
	{ XFER_SW_DMA_1,  90,   0,   0,   0, 240, 240, 480,   0 },
	{ XFER_SW_DMA_0, 120,   0,   0,   0, 480, 480, 960,   0 },

	{ XFER_PIO_6,     10,  55,  20,  80,  55,  20,  80,   0 },
	{ XFER_PIO_5,     15,  65,  25, 100,  65,  25, 100,   0 },
	{ XFER_PIO_4,     25,  70,  25, 120,  70,  25, 120,   0 },
	{ XFER_PIO_3,     30,  80,  70, 180,  80,  70, 180,   0 },

	{ XFER_PIO_2,     30, 290,  40, 330, 100,  90, 240,   0 },
	{ XFER_PIO_1,     50, 290,  93, 383, 125, 100, 383,   0 },
	{ XFER_PIO_0,     70, 290, 240, 600, 165, 150, 600,   0 },

	{ XFER_PIO_SLOW, 120, 290, 240, 960, 290, 240, 960,   0 },

	{ 0xff }
};

struct ide_timing *ide_timing_find_mode(u8 speed)
{
	struct ide_timing *t;

	for (t = ide_timing; t->mode != speed; t++)
		if (t->mode == 0xff)
			return NULL;
	return t;
}
EXPORT_SYMBOL_GPL(ide_timing_find_mode);

u16 ide_pio_cycle_time(ide_drive_t *drive, u8 pio)
{
	u16 *id = drive->id;
	struct ide_timing *t = ide_timing_find_mode(XFER_PIO_0 + pio);
	u16 cycle = 0;

	if (id[ATA_ID_FIELD_VALID] & 2) {
		if (ata_id_has_iordy(drive->id))
			cycle = id[ATA_ID_EIDE_PIO_IORDY];
		else
			cycle = id[ATA_ID_EIDE_PIO];

		/* conservative "downgrade" for all pre-ATA2 drives */
		if (pio < 3 && cycle < t->cycle)
			cycle = 0; /* use standard timing */

		/* Use the standard timing for the CF specific modes too */
		if (pio > 4 && ata_id_is_cfa(id))
			cycle = 0;
	}

	return cycle ? cycle : t->cycle;
}
EXPORT_SYMBOL_GPL(ide_pio_cycle_time);

#define ENOUGH(v, unit)		(((v) - 1) / (unit) + 1)
#define EZ(v, unit)		((v) ? ENOUGH(v, unit) : 0)

static void ide_timing_quantize(struct ide_timing *t, struct ide_timing *q,
				int T, int UT)
{
	q->setup   = EZ(t->setup   * 1000,  T);
	q->act8b   = EZ(t->act8b   * 1000,  T);
	q->rec8b   = EZ(t->rec8b   * 1000,  T);
	q->cyc8b   = EZ(t->cyc8b   * 1000,  T);
	q->active  = EZ(t->active  * 1000,  T);
	q->recover = EZ(t->recover * 1000,  T);
	q->cycle   = EZ(t->cycle   * 1000,  T);
	q->udma    = EZ(t->udma    * 1000, UT);
}

void ide_timing_merge(struct ide_timing *a, struct ide_timing *b,
		      struct ide_timing *m, unsigned int what)
{
	if (what & IDE_TIMING_SETUP)
		m->setup   = max(a->setup,   b->setup);
	if (what & IDE_TIMING_ACT8B)
		m->act8b   = max(a->act8b,   b->act8b);
	if (what & IDE_TIMING_REC8B)
		m->rec8b   = max(a->rec8b,   b->rec8b);
	if (what & IDE_TIMING_CYC8B)
		m->cyc8b   = max(a->cyc8b,   b->cyc8b);
	if (what & IDE_TIMING_ACTIVE)
		m->active  = max(a->active,  b->active);
	if (what & IDE_TIMING_RECOVER)
		m->recover = max(a->recover, b->recover);
	if (what & IDE_TIMING_CYCLE)
		m->cycle   = max(a->cycle,   b->cycle);
	if (what & IDE_TIMING_UDMA)
		m->udma    = max(a->udma,    b->udma);
}
EXPORT_SYMBOL_GPL(ide_timing_merge);

int ide_timing_compute(ide_drive_t *drive, u8 speed,
		       struct ide_timing *t, int T, int UT)
{
	u16 *id = drive->id;
	struct ide_timing *s, p;

	/*
	 * Find the mode.
	 */
	s = ide_timing_find_mode(speed);
	if (s == NULL)
		return -EINVAL;

	/*
	 * Copy the timing from the table.
	 */
	*t = *s;

	/*
	 * If the drive is an EIDE drive, it can tell us it needs extended
	 * PIO/MWDMA cycle timing.
	 */
	if (id[ATA_ID_FIELD_VALID] & 2) {	/* EIDE drive */
		memset(&p, 0, sizeof(p));

		if (speed >= XFER_PIO_0 && speed <= XFER_SW_DMA_0) {
			if (speed <= XFER_PIO_2)
				p.cycle = p.cyc8b = id[ATA_ID_EIDE_PIO];
			else if ((speed <= XFER_PIO_4) ||
				 (speed == XFER_PIO_5 && !ata_id_is_cfa(id)))
				p.cycle = p.cyc8b = id[ATA_ID_EIDE_PIO_IORDY];
		} else if (speed >= XFER_MW_DMA_0 && speed <= XFER_MW_DMA_2)
			p.cycle = id[ATA_ID_EIDE_DMA_MIN];

		ide_timing_merge(&p, t, t, IDE_TIMING_CYCLE | IDE_TIMING_CYC8B);
	}

	/*
	 * Convert the timing to bus clock counts.
	 */
	ide_timing_quantize(t, t, T, UT);

	/*
	 * Even in DMA/UDMA modes we still use PIO access for IDENTIFY,
	 * S.M.A.R.T and some other commands. We have to ensure that the
	 * DMA cycle timing is slower/equal than the current PIO timing.
	 */
	if (speed >= XFER_SW_DMA_0) {
		ide_timing_compute(drive, drive->pio_mode, &p, T, UT);
		ide_timing_merge(&p, t, t, IDE_TIMING_ALL);
	}

	/*
	 * Lengthen active & recovery time so that cycle time is correct.
	 */
	if (t->act8b + t->rec8b < t->cyc8b) {
		t->act8b += (t->cyc8b - (t->act8b + t->rec8b)) / 2;
		t->rec8b = t->cyc8b - t->act8b;
	}

	if (t->active + t->recover < t->cycle) {
		t->active += (t->cycle - (t->active + t->recover)) / 2;
		t->recover = t->cycle - t->active;
	}

	return 0;
}
EXPORT_SYMBOL_GPL(ide_timing_compute);