diff options
Diffstat (limited to 'drivers/ata/libata-pata-timings.c')
| -rw-r--r-- | drivers/ata/libata-pata-timings.c | 192 |
1 files changed, 192 insertions, 0 deletions
diff --git a/drivers/ata/libata-pata-timings.c b/drivers/ata/libata-pata-timings.c new file mode 100644 index 000000000..af341226c --- /dev/null +++ b/drivers/ata/libata-pata-timings.c @@ -0,0 +1,192 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * Helper library for PATA timings + * + * Copyright 2003-2004 Red Hat, Inc. All rights reserved. + * Copyright 2003-2004 Jeff Garzik + */ + +#include <linux/kernel.h> +#include <linux/module.h> +#include <linux/libata.h> + +/* + * This mode timing computation functionality is ported over from + * drivers/ide/ide-timing.h and was originally written by Vojtech Pavlik + */ +/* + * PIO 0-4, MWDMA 0-2 and UDMA 0-6 timings (in nanoseconds). + * These were taken from ATA/ATAPI-6 standard, rev 0a, except + * for UDMA6, which is currently supported only by Maxtor drives. + * + * For PIO 5/6 MWDMA 3/4 see the CFA specification 3.0. + */ + +static const struct ata_timing ata_timing[] = { +/* { XFER_PIO_SLOW, 120, 290, 240, 960, 290, 240, 0, 960, 0 }, */ + { XFER_PIO_0, 70, 290, 240, 600, 165, 150, 0, 600, 0 }, + { XFER_PIO_1, 50, 290, 93, 383, 125, 100, 0, 383, 0 }, + { XFER_PIO_2, 30, 290, 40, 330, 100, 90, 0, 240, 0 }, + { XFER_PIO_3, 30, 80, 70, 180, 80, 70, 0, 180, 0 }, + { XFER_PIO_4, 25, 70, 25, 120, 70, 25, 0, 120, 0 }, + { XFER_PIO_5, 15, 65, 25, 100, 65, 25, 0, 100, 0 }, + { XFER_PIO_6, 10, 55, 20, 80, 55, 20, 0, 80, 0 }, + + { XFER_SW_DMA_0, 120, 0, 0, 0, 480, 480, 50, 960, 0 }, + { XFER_SW_DMA_1, 90, 0, 0, 0, 240, 240, 30, 480, 0 }, + { XFER_SW_DMA_2, 60, 0, 0, 0, 120, 120, 20, 240, 0 }, + + { XFER_MW_DMA_0, 60, 0, 0, 0, 215, 215, 20, 480, 0 }, + { XFER_MW_DMA_1, 45, 0, 0, 0, 80, 50, 5, 150, 0 }, + { XFER_MW_DMA_2, 25, 0, 0, 0, 70, 25, 5, 120, 0 }, + { XFER_MW_DMA_3, 25, 0, 0, 0, 65, 25, 5, 100, 0 }, + { XFER_MW_DMA_4, 25, 0, 0, 0, 55, 20, 5, 80, 0 }, + +/* { XFER_UDMA_SLOW, 0, 0, 0, 0, 0, 0, 0, 0, 150 }, */ + { XFER_UDMA_0, 0, 0, 0, 0, 0, 0, 0, 0, 120 }, + { XFER_UDMA_1, 0, 0, 0, 0, 0, 0, 0, 0, 80 }, + { XFER_UDMA_2, 0, 0, 0, 0, 0, 0, 0, 0, 60 }, + { XFER_UDMA_3, 0, 0, 0, 0, 0, 0, 0, 0, 45 }, + { XFER_UDMA_4, 0, 0, 0, 0, 0, 0, 0, 0, 30 }, + { XFER_UDMA_5, 0, 0, 0, 0, 0, 0, 0, 0, 20 }, + { XFER_UDMA_6, 0, 0, 0, 0, 0, 0, 0, 0, 15 }, + + { 0xFF } +}; + +#define ENOUGH(v, unit) (((v)-1)/(unit)+1) +#define EZ(v, unit) ((v)?ENOUGH(((v) * 1000), unit):0) + +static void ata_timing_quantize(const struct ata_timing *t, + struct ata_timing *q, int T, int UT) +{ + q->setup = EZ(t->setup, T); + q->act8b = EZ(t->act8b, T); + q->rec8b = EZ(t->rec8b, T); + q->cyc8b = EZ(t->cyc8b, T); + q->active = EZ(t->active, T); + q->recover = EZ(t->recover, T); + q->dmack_hold = EZ(t->dmack_hold, T); + q->cycle = EZ(t->cycle, T); + q->udma = EZ(t->udma, UT); +} + +void ata_timing_merge(const struct ata_timing *a, const struct ata_timing *b, + struct ata_timing *m, unsigned int what) +{ + if (what & ATA_TIMING_SETUP) + m->setup = max(a->setup, b->setup); + if (what & ATA_TIMING_ACT8B) + m->act8b = max(a->act8b, b->act8b); + if (what & ATA_TIMING_REC8B) + m->rec8b = max(a->rec8b, b->rec8b); + if (what & ATA_TIMING_CYC8B) + m->cyc8b = max(a->cyc8b, b->cyc8b); + if (what & ATA_TIMING_ACTIVE) + m->active = max(a->active, b->active); + if (what & ATA_TIMING_RECOVER) + m->recover = max(a->recover, b->recover); + if (what & ATA_TIMING_DMACK_HOLD) + m->dmack_hold = max(a->dmack_hold, b->dmack_hold); + if (what & ATA_TIMING_CYCLE) + m->cycle = max(a->cycle, b->cycle); + if (what & ATA_TIMING_UDMA) + m->udma = max(a->udma, b->udma); +} +EXPORT_SYMBOL_GPL(ata_timing_merge); + +const struct ata_timing *ata_timing_find_mode(u8 xfer_mode) +{ + const struct ata_timing *t = ata_timing; + + while (xfer_mode > t->mode) + t++; + + if (xfer_mode == t->mode) + return t; + + WARN_ONCE(true, "%s: unable to find timing for xfer_mode 0x%x\n", + __func__, xfer_mode); + + return NULL; +} +EXPORT_SYMBOL_GPL(ata_timing_find_mode); + +int ata_timing_compute(struct ata_device *adev, unsigned short speed, + struct ata_timing *t, int T, int UT) +{ + const u16 *id = adev->id; + const struct ata_timing *s; + struct ata_timing p; + + /* + * Find the mode. + */ + s = ata_timing_find_mode(speed); + if (!s) + return -EINVAL; + + memcpy(t, s, sizeof(*s)); + + /* + * If the drive is an EIDE drive, it can tell us it needs extended + * PIO/MW_DMA 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]; + + ata_timing_merge(&p, t, t, ATA_TIMING_CYCLE | ATA_TIMING_CYC8B); + } + + /* + * Convert the timing to bus clock counts. + */ + + ata_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_PIO_6) { + ata_timing_compute(adev, adev->pio_mode, &p, T, UT); + ata_timing_merge(&p, t, t, ATA_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; + } + + /* + * In a few cases quantisation may produce enough errors to + * leave t->cycle too low for the sum of active and recovery + * if so we must correct this. + */ + if (t->active + t->recover > t->cycle) + t->cycle = t->active + t->recover; + + return 0; +} +EXPORT_SYMBOL_GPL(ata_timing_compute); |