193 lines
5.8 KiB
C
193 lines
5.8 KiB
C
// SPDX-License-Identifier: GPL-2.0-or-later
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/*
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* Helper library for PATA timings
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*
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* Copyright 2003-2004 Red Hat, Inc. All rights reserved.
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* Copyright 2003-2004 Jeff Garzik
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*/
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#include <linux/kernel.h>
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#include <linux/module.h>
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#include <linux/libata.h>
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/*
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* This mode timing computation functionality is ported over from
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* drivers/ide/ide-timing.h and was originally written by Vojtech Pavlik
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*/
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/*
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* PIO 0-4, MWDMA 0-2 and UDMA 0-6 timings (in nanoseconds).
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* These were taken from ATA/ATAPI-6 standard, rev 0a, except
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* for UDMA6, which is currently supported only by Maxtor drives.
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*
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* For PIO 5/6 MWDMA 3/4 see the CFA specification 3.0.
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*/
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static const struct ata_timing ata_timing[] = {
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/* { XFER_PIO_SLOW, 120, 290, 240, 960, 290, 240, 0, 960, 0 }, */
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{ XFER_PIO_0, 70, 290, 240, 600, 165, 150, 0, 600, 0 },
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{ XFER_PIO_1, 50, 290, 93, 383, 125, 100, 0, 383, 0 },
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{ XFER_PIO_2, 30, 290, 40, 330, 100, 90, 0, 240, 0 },
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{ XFER_PIO_3, 30, 80, 70, 180, 80, 70, 0, 180, 0 },
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{ XFER_PIO_4, 25, 70, 25, 120, 70, 25, 0, 120, 0 },
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{ XFER_PIO_5, 15, 65, 25, 100, 65, 25, 0, 100, 0 },
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{ XFER_PIO_6, 10, 55, 20, 80, 55, 20, 0, 80, 0 },
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{ XFER_SW_DMA_0, 120, 0, 0, 0, 480, 480, 50, 960, 0 },
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{ XFER_SW_DMA_1, 90, 0, 0, 0, 240, 240, 30, 480, 0 },
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{ XFER_SW_DMA_2, 60, 0, 0, 0, 120, 120, 20, 240, 0 },
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{ XFER_MW_DMA_0, 60, 0, 0, 0, 215, 215, 20, 480, 0 },
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{ XFER_MW_DMA_1, 45, 0, 0, 0, 80, 50, 5, 150, 0 },
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{ XFER_MW_DMA_2, 25, 0, 0, 0, 70, 25, 5, 120, 0 },
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{ XFER_MW_DMA_3, 25, 0, 0, 0, 65, 25, 5, 100, 0 },
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{ XFER_MW_DMA_4, 25, 0, 0, 0, 55, 20, 5, 80, 0 },
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/* { XFER_UDMA_SLOW, 0, 0, 0, 0, 0, 0, 0, 0, 150 }, */
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{ XFER_UDMA_0, 0, 0, 0, 0, 0, 0, 0, 0, 120 },
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{ XFER_UDMA_1, 0, 0, 0, 0, 0, 0, 0, 0, 80 },
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{ XFER_UDMA_2, 0, 0, 0, 0, 0, 0, 0, 0, 60 },
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{ XFER_UDMA_3, 0, 0, 0, 0, 0, 0, 0, 0, 45 },
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{ XFER_UDMA_4, 0, 0, 0, 0, 0, 0, 0, 0, 30 },
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{ XFER_UDMA_5, 0, 0, 0, 0, 0, 0, 0, 0, 20 },
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{ XFER_UDMA_6, 0, 0, 0, 0, 0, 0, 0, 0, 15 },
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{ 0xFF }
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};
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#define ENOUGH(v, unit) (((v)-1)/(unit)+1)
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#define EZ(v, unit) ((v)?ENOUGH(((v) * 1000), unit):0)
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static void ata_timing_quantize(const struct ata_timing *t,
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struct ata_timing *q, int T, int UT)
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{
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q->setup = EZ(t->setup, T);
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q->act8b = EZ(t->act8b, T);
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q->rec8b = EZ(t->rec8b, T);
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q->cyc8b = EZ(t->cyc8b, T);
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q->active = EZ(t->active, T);
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q->recover = EZ(t->recover, T);
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q->dmack_hold = EZ(t->dmack_hold, T);
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q->cycle = EZ(t->cycle, T);
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q->udma = EZ(t->udma, UT);
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}
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void ata_timing_merge(const struct ata_timing *a, const struct ata_timing *b,
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struct ata_timing *m, unsigned int what)
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{
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if (what & ATA_TIMING_SETUP)
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m->setup = max(a->setup, b->setup);
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if (what & ATA_TIMING_ACT8B)
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m->act8b = max(a->act8b, b->act8b);
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if (what & ATA_TIMING_REC8B)
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m->rec8b = max(a->rec8b, b->rec8b);
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if (what & ATA_TIMING_CYC8B)
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m->cyc8b = max(a->cyc8b, b->cyc8b);
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if (what & ATA_TIMING_ACTIVE)
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m->active = max(a->active, b->active);
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if (what & ATA_TIMING_RECOVER)
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m->recover = max(a->recover, b->recover);
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if (what & ATA_TIMING_DMACK_HOLD)
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m->dmack_hold = max(a->dmack_hold, b->dmack_hold);
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if (what & ATA_TIMING_CYCLE)
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m->cycle = max(a->cycle, b->cycle);
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if (what & ATA_TIMING_UDMA)
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m->udma = max(a->udma, b->udma);
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}
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EXPORT_SYMBOL_GPL(ata_timing_merge);
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const struct ata_timing *ata_timing_find_mode(u8 xfer_mode)
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{
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const struct ata_timing *t = ata_timing;
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while (xfer_mode > t->mode)
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t++;
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if (xfer_mode == t->mode)
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return t;
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WARN_ONCE(true, "%s: unable to find timing for xfer_mode 0x%x\n",
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__func__, xfer_mode);
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return NULL;
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}
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EXPORT_SYMBOL_GPL(ata_timing_find_mode);
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int ata_timing_compute(struct ata_device *adev, unsigned short speed,
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struct ata_timing *t, int T, int UT)
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{
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const u16 *id = adev->id;
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const struct ata_timing *s;
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struct ata_timing p;
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/*
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* Find the mode.
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*/
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s = ata_timing_find_mode(speed);
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if (!s)
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return -EINVAL;
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memcpy(t, s, sizeof(*s));
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/*
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* If the drive is an EIDE drive, it can tell us it needs extended
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* PIO/MW_DMA cycle timing.
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*/
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if (id[ATA_ID_FIELD_VALID] & 2) { /* EIDE drive */
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memset(&p, 0, sizeof(p));
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if (speed >= XFER_PIO_0 && speed < XFER_SW_DMA_0) {
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if (speed <= XFER_PIO_2)
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p.cycle = p.cyc8b = id[ATA_ID_EIDE_PIO];
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else if ((speed <= XFER_PIO_4) ||
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(speed == XFER_PIO_5 && !ata_id_is_cfa(id)))
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p.cycle = p.cyc8b = id[ATA_ID_EIDE_PIO_IORDY];
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} else if (speed >= XFER_MW_DMA_0 && speed <= XFER_MW_DMA_2)
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p.cycle = id[ATA_ID_EIDE_DMA_MIN];
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ata_timing_merge(&p, t, t, ATA_TIMING_CYCLE | ATA_TIMING_CYC8B);
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}
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/*
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* Convert the timing to bus clock counts.
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*/
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ata_timing_quantize(t, t, T, UT);
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/*
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* Even in DMA/UDMA modes we still use PIO access for IDENTIFY,
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* S.M.A.R.T * and some other commands. We have to ensure that the
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* DMA cycle timing is slower/equal than the fastest PIO timing.
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*/
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if (speed > XFER_PIO_6) {
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ata_timing_compute(adev, adev->pio_mode, &p, T, UT);
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ata_timing_merge(&p, t, t, ATA_TIMING_ALL);
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}
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/*
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* Lengthen active & recovery time so that cycle time is correct.
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*/
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if (t->act8b + t->rec8b < t->cyc8b) {
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t->act8b += (t->cyc8b - (t->act8b + t->rec8b)) / 2;
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t->rec8b = t->cyc8b - t->act8b;
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}
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if (t->active + t->recover < t->cycle) {
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t->active += (t->cycle - (t->active + t->recover)) / 2;
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t->recover = t->cycle - t->active;
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}
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/*
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* In a few cases quantisation may produce enough errors to
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* leave t->cycle too low for the sum of active and recovery
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* if so we must correct this.
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*/
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if (t->active + t->recover > t->cycle)
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t->cycle = t->active + t->recover;
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return 0;
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}
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EXPORT_SYMBOL_GPL(ata_timing_compute);
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