/*
* 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_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_5, 20, 50, 30, 100, 50, 30, 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 */
}
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_2)
p.cycle = p.cyc8b = id[ATA_ID_EIDE_PIO];
else if (speed <= XFER_PIO_5)
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 fastest PIO timing.
*/
if (speed >= XFER_SW_DMA_0) {
u8 pio = ide_get_best_pio_mode(drive, 255, 5);
ide_timing_compute(drive, XFER_PIO_0 + pio, &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);
