drivers/ide/ide-timings.c

   1 /*
   2  *  Copyright (c) 1999-2001 Vojtech Pavlik
   3  *  Copyright (c) 2007-2008 Bartlomiej Zolnierkiewicz
   4  *
   5  * This program is free software; you can redistribute it and/or modify
   6  * it under the terms of the GNU General Public License as published by
   7  * the Free Software Foundation; either version 2 of the License, or
   8  * (at your option) any later version.
   9  *
  10  * This program is distributed in the hope that it will be useful,
  11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13  * GNU General Public License for more details.
  14  *
  15  * You should have received a copy of the GNU General Public License
  16  * along with this program; if not, write to the Free Software
  17  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
  18  *
  19  * Should you need to contact me, the author, you can do so either by
  20  * e-mail - mail your message to <vojtech@ucw.cz>, or by paper mail:
  21  * Vojtech Pavlik, Simunkova 1594, Prague 8, 182 00 Czech Republic
  22  */
  23
  24 #include <linux/kernel.h>
  25 #include <linux/ide.h>
  26 #include <linux/module.h>
  27
  28 /*
  29  * PIO 0-5, MWDMA 0-2 and UDMA 0-6 timings (in nanoseconds).
  30  * These were taken from ATA/ATAPI-6 standard, rev 0a, except
  31  * for PIO 5, which is a nonstandard extension and UDMA6, which
  32  * is currently supported only by Maxtor drives.
  33  */
  34
  35 static struct ide_timing ide_timing[] = {
  36
  37         { XFER_UDMA_6,     0,   0,   0,   0,   0,   0,   0,  15 },
  38         { XFER_UDMA_5,     0,   0,   0,   0,   0,   0,   0,  20 },
  39         { XFER_UDMA_4,     0,   0,   0,   0,   0,   0,   0,  30 },
  40         { XFER_UDMA_3,     0,   0,   0,   0,   0,   0,   0,  45 },
  41
  42         { XFER_UDMA_2,     0,   0,   0,   0,   0,   0,   0,  60 },
  43         { XFER_UDMA_1,     0,   0,   0,   0,   0,   0,   0,  80 },
  44         { XFER_UDMA_0,     0,   0,   0,   0,   0,   0,   0, 120 },
  45
  46         { XFER_MW_DMA_4,  25,   0,   0,   0,  55,  20,  80,   0 },
  47         { XFER_MW_DMA_3,  25,   0,   0,   0,  65,  25, 100,   0 },
  48         { XFER_MW_DMA_2,  25,   0,   0,   0,  70,  25, 120,   0 },
  49         { XFER_MW_DMA_1,  45,   0,   0,   0,  80,  50, 150,   0 },
  50         { XFER_MW_DMA_0,  60,   0,   0,   0, 215, 215, 480,   0 },
  51
  52         { XFER_SW_DMA_2,  60,   0,   0,   0, 120, 120, 240,   0 },
  53         { XFER_SW_DMA_1,  90,   0,   0,   0, 240, 240, 480,   0 },
  54         { XFER_SW_DMA_0, 120,   0,   0,   0, 480, 480, 960,   0 },
  55
  56         { XFER_PIO_6,     10,  55,  20,  80,  55,  20,  80,   0 },
  57         { XFER_PIO_5,     15,  65,  25, 100,  65,  25, 100,   0 },
  58         { XFER_PIO_4,     25,  70,  25, 120,  70,  25, 120,   0 },
  59         { XFER_PIO_3,     30,  80,  70, 180,  80,  70, 180,   0 },
  60
  61         { XFER_PIO_2,     30, 290,  40, 330, 100,  90, 240,   0 },
  62         { XFER_PIO_1,     50, 290,  93, 383, 125, 100, 383,   0 },
  63         { XFER_PIO_0,     70, 290, 240, 600, 165, 150, 600,   0 },
  64
  65         { XFER_PIO_SLOW, 120, 290, 240, 960, 290, 240, 960,   0 },
  66
  67         { 0xff }
  68 };
  69
  70 struct ide_timing *ide_timing_find_mode(u8 speed)
  71 {
  72         struct ide_timing *t;
  73
  74         for (t = ide_timing; t->mode != speed; t++)
  75                 if (t->mode == 0xff)
  76                         return NULL;
  77         return t;
  78 }
  79 EXPORT_SYMBOL_GPL(ide_timing_find_mode);
  80
  81 u16 ide_pio_cycle_time(ide_drive_t *drive, u8 pio)
  82 {
  83         u16 *id = drive->id;
  84         struct ide_timing *t = ide_timing_find_mode(XFER_PIO_0 + pio);
  85         u16 cycle = 0;
  86
  87         if (id[ATA_ID_FIELD_VALID] & 2) {
  88                 if (ata_id_has_iordy(drive->id))
  89                         cycle = id[ATA_ID_EIDE_PIO_IORDY];
  90                 else
  91                         cycle = id[ATA_ID_EIDE_PIO];
  92
  93                 /* conservative "downgrade" for all pre-ATA2 drives */
  94                 if (pio < 3 && cycle < t->cycle)
  95                         cycle = 0; /* use standard timing */
  96
  97                 /* Use the standard timing for the CF specific modes too */
  98                 if (pio > 4 && ata_id_is_cfa(id))
  99                         cycle = 0;
 100         }
 101
 102         return cycle ? cycle : t->cycle;
 103 }
 104 EXPORT_SYMBOL_GPL(ide_pio_cycle_time);
 105
 106 #define ENOUGH(v, unit)         (((v) - 1) / (unit) + 1)
 107 #define EZ(v, unit)             ((v) ? ENOUGH(v, unit) : 0)
 108
 109 static void ide_timing_quantize(struct ide_timing *t, struct ide_timing *q,
 110                                 int T, int UT)
 111 {
 112         q->setup   = EZ(t->setup   * 1000,  T);
 113         q->act8b   = EZ(t->act8b   * 1000,  T);
 114         q->rec8b   = EZ(t->rec8b   * 1000,  T);
 115         q->cyc8b   = EZ(t->cyc8b   * 1000,  T);
 116         q->active  = EZ(t->active  * 1000,  T);
 117         q->recover = EZ(t->recover * 1000,  T);
 118         q->cycle   = EZ(t->cycle   * 1000,  T);
 119         q->udma    = EZ(t->udma    * 1000, UT);
 120 }
 121
 122 void ide_timing_merge(struct ide_timing *a, struct ide_timing *b,
 123                       struct ide_timing *m, unsigned int what)
 124 {
 125         if (what & IDE_TIMING_SETUP)
 126                 m->setup   = max(a->setup,   b->setup);
 127         if (what & IDE_TIMING_ACT8B)
 128                 m->act8b   = max(a->act8b,   b->act8b);
 129         if (what & IDE_TIMING_REC8B)
 130                 m->rec8b   = max(a->rec8b,   b->rec8b);
 131         if (what & IDE_TIMING_CYC8B)
 132                 m->cyc8b   = max(a->cyc8b,   b->cyc8b);
 133         if (what & IDE_TIMING_ACTIVE)
 134                 m->active  = max(a->active,  b->active);
 135         if (what & IDE_TIMING_RECOVER)
 136                 m->recover = max(a->recover, b->recover);
 137         if (what & IDE_TIMING_CYCLE)
 138                 m->cycle   = max(a->cycle,   b->cycle);
 139         if (what & IDE_TIMING_UDMA)
 140                 m->udma    = max(a->udma,    b->udma);
 141 }
 142 EXPORT_SYMBOL_GPL(ide_timing_merge);
 143
 144 int ide_timing_compute(ide_drive_t *drive, u8 speed,
 145                        struct ide_timing *t, int T, int UT)
 146 {
 147         u16 *id = drive->id;
 148         struct ide_timing *s, p;
 149
 150         /*
 151          * Find the mode.
 152          */
 153         s = ide_timing_find_mode(speed);
 154         if (s == NULL)
 155                 return -EINVAL;
 156
 157         /*
 158          * Copy the timing from the table.
 159          */
 160         *t = *s;
 161
 162         /*
 163          * If the drive is an EIDE drive, it can tell us it needs extended
 164          * PIO/MWDMA cycle timing.
 165          */
 166         if (id[ATA_ID_FIELD_VALID] & 2) {       /* EIDE drive */
 167                 memset(&p, 0, sizeof(p));
 168
 169                 if (speed <= XFER_PIO_2)
 170                         p.cycle = p.cyc8b = id[ATA_ID_EIDE_PIO];
 171                 else if ((speed <= XFER_PIO_4) ||
 172                          (speed == XFER_PIO_5 && !ata_id_is_cfa(id)))
 173                         p.cycle = p.cyc8b = id[ATA_ID_EIDE_PIO_IORDY];
 174                 else if (speed >= XFER_MW_DMA_0 && speed <= XFER_MW_DMA_2)
 175                         p.cycle = id[ATA_ID_EIDE_DMA_MIN];
 176
 177                 ide_timing_merge(&p, t, t, IDE_TIMING_CYCLE | IDE_TIMING_CYC8B);
 178         }
 179
 180         /*
 181          * Convert the timing to bus clock counts.
 182          */
 183         ide_timing_quantize(t, t, T, UT);
 184
 185         /*
 186          * Even in DMA/UDMA modes we still use PIO access for IDENTIFY,
 187          * S.M.A.R.T and some other commands. We have to ensure that the
 188          * DMA cycle timing is slower/equal than the fastest PIO timing.
 189          */
 190         if (speed >= XFER_SW_DMA_0) {
 191                 u8 pio = ide_get_best_pio_mode(drive, 255, 5);
 192                 ide_timing_compute(drive, XFER_PIO_0 + pio, &p, T, UT);
 193                 ide_timing_merge(&p, t, t, IDE_TIMING_ALL);
 194         }
 195
 196         /*
 197          * Lengthen active & recovery time so that cycle time is correct.
 198          */
 199         if (t->act8b + t->rec8b < t->cyc8b) {
 200                 t->act8b += (t->cyc8b - (t->act8b + t->rec8b)) / 2;
 201                 t->rec8b = t->cyc8b - t->act8b;
 202         }
 203
 204         if (t->active + t->recover < t->cycle) {
 205                 t->active += (t->cycle - (t->active + t->recover)) / 2;
 206                 t->recover = t->cycle - t->active;
 207         }
 208
 209         return 0;
 210 }
 211 EXPORT_SYMBOL_GPL(ide_timing_compute);