1 files changed, 205 insertions, 0 deletions

diff --git a/drivers/ide/ide-timings.c b/drivers/ide/ide-timings.c
new file mode 100644
index 000000000000..8c2f8327f487
--- /dev/null
+++ b/drivers/ide/ide-timings.c
@@ -0,0 +1,205 @@
+/*
+ *  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/hdreg.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)
+{
+        struct hd_driveid *id = drive->id;
+        struct ide_timing *t = ide_timing_find_mode(XFER_PIO_0 + pio);
+        u16 cycle = 0;
+
+        if (id->field_valid & 2) {
+                if (id->capability & 8)
+                        cycle = id->eide_pio_iordy;
+                else
+                        cycle = 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)
+{
+        struct hd_driveid *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 && id->field_valid & 2) {        /* EIDE drive */
+
+                memset(&p, 0, sizeof(p));
+
+                if (speed <= XFER_PIO_2)
+                        p.cycle = p.cyc8b = id->eide_pio;
+                else if (speed <= XFER_PIO_5)
+                        p.cycle = p.cyc8b = id->eide_pio_iordy;
+                else if (speed >= XFER_MW_DMA_0 && speed <= XFER_MW_DMA_2)
+                        p.cycle = 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);