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Subject[PATCH v4 12/27] ata: separate PATA timings code from libata-core.c
Date
Separate PATA timings code from libata-core.c:

* add PATA_TIMINGS config option and make corresponding PATA
host drivers (and ATA ACPI code) select it

* move following PATA timings code to libata-pata-timings.c:
- ata_timing_quantize()
- ata_timing_merge()
- ata_timing_find_mode()
- ata_timing_compute()

* group above functions together in <linux/libata.h>

* include libata-pata-timings.c in the build when PATA_TIMINGS
config option is enabled

* cover ata_timing_cycle2mode() with CONFIG_ATA_ACPI ifdef (it
depends on code from libata-core.c and libata-pata-timings.c
while its only user is ATA ACPI)

Code size savings on m68k arch using (modified) atari_defconfig:

text data bss dec hex filename
before:
39688 573 40 40301 9d6d drivers/ata/libata-core.o
after:
37820 572 40 38432 9620 drivers/ata/libata-core.o

Signed-off-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
---
drivers/ata/Kconfig | 21 ++++
drivers/ata/Makefile | 1 +
drivers/ata/libata-core.c | 183 +---------------------------
drivers/ata/libata-pata-timings.c | 192 ++++++++++++++++++++++++++++++
include/linux/libata.h | 16 ++-
5 files changed, 226 insertions(+), 187 deletions(-)
create mode 100644 drivers/ata/libata-pata-timings.c

diff --git a/drivers/ata/Kconfig b/drivers/ata/Kconfig
index ad7760656f71..5b55ebf56b5a 100644
--- a/drivers/ata/Kconfig
+++ b/drivers/ata/Kconfig
@@ -37,6 +37,9 @@ config ATA_NONSTANDARD
config SATA_HOST
bool

+config PATA_TIMINGS
+ bool
+
config ATA_VERBOSE_ERROR
bool "Verbose ATA error reporting"
default y
@@ -51,6 +54,7 @@ config ATA_VERBOSE_ERROR
config ATA_ACPI
bool "ATA ACPI Support"
depends on ACPI
+ select PATA_TIMINGS
default y
help
This option adds support for ATA-related ACPI objects.
@@ -341,6 +345,7 @@ config PDC_ADMA
config PATA_OCTEON_CF
tristate "OCTEON Boot Bus Compact Flash support"
depends on CAVIUM_OCTEON_SOC
+ select PATA_TIMINGS
help
This option enables a polled compact flash driver for use with
compact flash cards attached to the OCTEON boot bus.
@@ -536,6 +541,7 @@ comment "PATA SFF controllers with BMDMA"
config PATA_ALI
tristate "ALi PATA support"
depends on PCI
+ select PATA_TIMINGS
help
This option enables support for the ALi ATA interfaces
found on the many ALi chipsets.
@@ -545,6 +551,7 @@ config PATA_ALI
config PATA_AMD
tristate "AMD/NVidia PATA support"
depends on PCI
+ select PATA_TIMINGS
help
This option enables support for the AMD and NVidia PATA
interfaces found on the chipsets for Athlon/Athlon64.
@@ -579,6 +586,7 @@ config PATA_ATIIXP
config PATA_ATP867X
tristate "ARTOP/Acard ATP867X PATA support"
depends on PCI
+ select PATA_TIMINGS
help
This option enables support for ARTOP/Acard ATP867X PATA
controllers.
@@ -588,6 +596,7 @@ config PATA_ATP867X
config PATA_BK3710
tristate "Palmchip BK3710 PATA support"
depends on ARCH_DAVINCI
+ select PATA_TIMINGS
help
This option enables support for the integrated IDE controller on
the TI DaVinci SoC.
@@ -597,6 +606,7 @@ config PATA_BK3710
config PATA_CMD64X
tristate "CMD64x PATA support"
depends on PCI
+ select PATA_TIMINGS
help
This option enables support for the CMD64x series chips
except for the CMD640.
@@ -642,6 +652,7 @@ config PATA_CS5536
config PATA_CYPRESS
tristate "Cypress CY82C693 PATA support (Very Experimental)"
depends on PCI
+ select PATA_TIMINGS
help
This option enables support for the Cypress/Contaq CY82C693
chipset found in some Alpha systems
@@ -660,6 +671,7 @@ config PATA_EFAR
config PATA_EP93XX
tristate "Cirrus Logic EP93xx PATA support"
depends on ARCH_EP93XX
+ select PATA_TIMINGS
help
This option enables support for the PATA controller in
the Cirrus Logic EP9312 and EP9315 ARM CPU.
@@ -724,6 +736,7 @@ config PATA_HPT3X3_DMA
config PATA_ICSIDE
tristate "Acorn ICS PATA support"
depends on ARM && ARCH_ACORN
+ select PATA_TIMINGS
help
On Acorn systems, say Y here if you wish to use the ICS PATA
interface card. This is not required for ICS partition support.
@@ -732,6 +745,7 @@ config PATA_ICSIDE
config PATA_IMX
tristate "PATA support for Freescale iMX"
depends on ARCH_MXC
+ select PATA_TIMINGS
help
This option enables support for the PATA host available on Freescale
iMX SoCs.
@@ -817,6 +831,7 @@ config PATA_NINJA32
config PATA_NS87415
tristate "Nat Semi NS87415 PATA support"
depends on PCI
+ select PATA_TIMINGS
help
This option enables support for the National Semiconductor
NS87415 PCI-IDE controller.
@@ -941,6 +956,7 @@ config PATA_TRIFLEX
config PATA_VIA
tristate "VIA PATA support"
depends on PCI
+ select PATA_TIMINGS
help
This option enables support for the VIA PATA interfaces
found on the many VIA chipsets.
@@ -974,6 +990,7 @@ comment "PIO-only SFF controllers"
config PATA_CMD640_PCI
tristate "CMD640 PCI PATA support (Experimental)"
depends on PCI
+ select PATA_TIMINGS
help
This option enables support for the CMD640 PCI IDE
interface chip. Only the primary channel is currently
@@ -1044,6 +1061,7 @@ config PATA_MPIIX
config PATA_NS87410
tristate "Nat Semi NS87410 PATA support"
depends on PCI
+ select PATA_TIMINGS
help
This option enables support for the National Semiconductor
NS87410 PCI-IDE controller.
@@ -1124,6 +1142,7 @@ config PATA_RZ1000
config PATA_SAMSUNG_CF
tristate "Samsung SoC PATA support"
depends on SAMSUNG_DEV_IDE
+ select PATA_TIMINGS
help
This option enables basic support for Samsung's S3C/S5P board
PATA controllers via the new ATA layer
@@ -1143,6 +1162,7 @@ comment "Generic fallback / legacy drivers"
config PATA_ACPI
tristate "ACPI firmware driver for PATA"
depends on ATA_ACPI && ATA_BMDMA && PCI
+ select PATA_TIMINGS
help
This option enables an ACPI method driver which drives
motherboard PATA controller interfaces through the ACPI
@@ -1162,6 +1182,7 @@ config ATA_GENERIC
config PATA_LEGACY
tristate "Legacy ISA PATA support (Experimental)"
depends on (ISA || PCI)
+ select PATA_TIMINGS
help
This option enables support for ISA/VLB/PCI bus legacy PATA
ports and allows them to be accessed via the new ATA layer.
diff --git a/drivers/ata/Makefile b/drivers/ata/Makefile
index d8cc2e04a6c7..cdaf965fed25 100644
--- a/drivers/ata/Makefile
+++ b/drivers/ata/Makefile
@@ -127,3 +127,4 @@ libata-$(CONFIG_ATA_SFF) += libata-sff.o
libata-$(CONFIG_SATA_PMP) += libata-pmp.o
libata-$(CONFIG_ATA_ACPI) += libata-acpi.o
libata-$(CONFIG_SATA_ZPODD) += libata-zpodd.o
+libata-$(CONFIG_PATA_TIMINGS) += libata-pata-timings.o
diff --git a/drivers/ata/libata-core.c b/drivers/ata/libata-core.c
index 52d32c88b854..f88fa4db2cab 100644
--- a/drivers/ata/libata-core.c
+++ b/drivers/ata/libata-core.c
@@ -3216,187 +3216,7 @@ int sata_set_spd(struct ata_link *link)
}
EXPORT_SYMBOL_GPL(sata_set_spd);

-/*
- * 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);
-
+#ifdef CONFIG_ATA_ACPI
/**
* ata_timing_cycle2mode - find xfer mode for the specified cycle duration
* @xfer_shift: ATA_SHIFT_* value for transfer type to examine.
@@ -3447,6 +3267,7 @@ u8 ata_timing_cycle2mode(unsigned int xfer_shift, int cycle)

return last_mode;
}
+#endif

/**
* ata_down_xfermask_limit - adjust dev xfer masks downward
diff --git a/drivers/ata/libata-pata-timings.c b/drivers/ata/libata-pata-timings.c
new file mode 100644
index 000000000000..af341226cc64
--- /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);
diff --git a/include/linux/libata.h b/include/linux/libata.h
index c6d94e40ca73..9ad072b6d007 100644
--- a/include/linux/libata.h
+++ b/include/linux/libata.h
@@ -1207,12 +1207,6 @@ extern int ata_cable_unknown(struct ata_port *ap);

/* Timing helpers */
extern unsigned int ata_pio_need_iordy(const struct ata_device *);
-extern const struct ata_timing *ata_timing_find_mode(u8 xfer_mode);
-extern int ata_timing_compute(struct ata_device *, unsigned short,
- struct ata_timing *, int, int);
-extern void ata_timing_merge(const struct ata_timing *,
- const struct ata_timing *, struct ata_timing *,
- unsigned int);
extern u8 ata_timing_cycle2mode(unsigned int xfer_shift, int cycle);

/* PCI */
@@ -1797,6 +1791,16 @@ static inline int ata_dma_enabled(struct ata_device *adev)
return (adev->dma_mode == 0xFF ? 0 : 1);
}

+/**************************************************************************
+ * PATA timings - drivers/ata/libata-pata-timings.c
+ */
+extern const struct ata_timing *ata_timing_find_mode(u8 xfer_mode);
+extern int ata_timing_compute(struct ata_device *, unsigned short,
+ struct ata_timing *, int, int);
+extern void ata_timing_merge(const struct ata_timing *,
+ const struct ata_timing *, struct ata_timing *,
+ unsigned int);
+
/**************************************************************************
* PMP - drivers/ata/libata-pmp.c
*/
--
2.24.1
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