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ata_piix: unify code for programming PIO and MWDMA timings
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Besides making things noticably simpler it results in ~2% decrease in
the driver LOC count and also ~2% decrease in the driver binary size
(as measured on x86-32).

Fix piix_set_piomode() documentation while at it.

Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>
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Bartlomiej Zolnierkiewicz authored and Jeff Garzik committed Oct 14, 2011
1 parent ce98669 commit 6a94a74
Showing 1 changed file with 38 additions and 73 deletions.
111 changes: 38 additions & 73 deletions drivers/ata/ata_piix.c
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Original file line number Diff line number Diff line change
Expand Up @@ -731,22 +731,11 @@ static int piix_pata_prereset(struct ata_link *link, unsigned long deadline)

static DEFINE_SPINLOCK(piix_lock);

/**
* piix_set_piomode - Initialize host controller PATA PIO timings
* @ap: Port whose timings we are configuring
* @adev: um
*
* Set PIO mode for device, in host controller PCI config space.
*
* LOCKING:
* None (inherited from caller).
*/

static void piix_set_piomode(struct ata_port *ap, struct ata_device *adev)
static void piix_set_timings(struct ata_port *ap, struct ata_device *adev,
u8 pio)
{
struct pci_dev *dev = to_pci_dev(ap->host->dev);
unsigned long flags;
unsigned int pio = adev->pio_mode - XFER_PIO_0;
unsigned int is_slave = (adev->devno != 0);
unsigned int master_port= ap->port_no ? 0x42 : 0x40;
unsigned int slave_port = 0x44;
Expand All @@ -771,10 +760,16 @@ static void piix_set_piomode(struct ata_port *ap, struct ata_device *adev)
control |= 1; /* TIME1 enable */
if (ata_pio_need_iordy(adev))
control |= 2; /* IE enable */

/* Intel specifies that the PPE functionality is for disk only */
if (adev->class == ATA_DEV_ATA)
control |= 4; /* PPE enable */
/*
* If the drive MWDMA is faster than it can do PIO then
* we must force PIO into PIO0
*/
if (adev->pio_mode < XFER_PIO_0 + pio)
/* Enable DMA timing only */
control |= 8; /* PIO cycles in PIO0 */

spin_lock_irqsave(&piix_lock, flags);

Expand Down Expand Up @@ -822,6 +817,22 @@ static void piix_set_piomode(struct ata_port *ap, struct ata_device *adev)
spin_unlock_irqrestore(&piix_lock, flags);
}

/**
* piix_set_piomode - Initialize host controller PATA PIO timings
* @ap: Port whose timings we are configuring
* @adev: Drive in question
*
* Set PIO mode for device, in host controller PCI config space.
*
* LOCKING:
* None (inherited from caller).
*/

static void piix_set_piomode(struct ata_port *ap, struct ata_device *adev)
{
piix_set_timings(ap, adev, adev->pio_mode - XFER_PIO_0);
}

/**
* do_pata_set_dmamode - Initialize host controller PATA PIO timings
* @ap: Port whose timings we are configuring
Expand All @@ -838,31 +849,20 @@ static void do_pata_set_dmamode(struct ata_port *ap, struct ata_device *adev, in
{
struct pci_dev *dev = to_pci_dev(ap->host->dev);
unsigned long flags;
u8 master_port = ap->port_no ? 0x42 : 0x40;
u16 master_data;
u8 speed = adev->dma_mode;
int devid = adev->devno + 2 * ap->port_no;
u8 udma_enable = 0;

static const /* ISP RTC */
u8 timings[][2] = { { 0, 0 },
{ 0, 0 },
{ 1, 0 },
{ 2, 1 },
{ 2, 3 }, };

spin_lock_irqsave(&piix_lock, flags);

pci_read_config_word(dev, master_port, &master_data);
if (ap->udma_mask)
pci_read_config_byte(dev, 0x48, &udma_enable);

if (speed >= XFER_UDMA_0) {
unsigned int udma = adev->dma_mode - XFER_UDMA_0;
unsigned int udma = speed - XFER_UDMA_0;
u16 udma_timing;
u16 ideconf;
int u_clock, u_speed;

spin_lock_irqsave(&piix_lock, flags);

pci_read_config_byte(dev, 0x48, &udma_enable);

/*
* UDMA is handled by a combination of clock switching and
* selection of dividers
Expand Down Expand Up @@ -895,56 +895,21 @@ static void do_pata_set_dmamode(struct ata_port *ap, struct ata_device *adev, in
performance (WR_PingPong_En) */
pci_write_config_word(dev, 0x54, ideconf);
}

pci_write_config_byte(dev, 0x48, udma_enable);

spin_unlock_irqrestore(&piix_lock, flags);
} else {
/*
* MWDMA is driven by the PIO timings. We must also enable
* IORDY unconditionally along with TIME1. PPE has already
* been set when the PIO timing was set.
*/
unsigned int mwdma = adev->dma_mode - XFER_MW_DMA_0;
unsigned int control;
u8 slave_data;
/* MWDMA is driven by the PIO timings. */
unsigned int mwdma = speed - XFER_MW_DMA_0;
const unsigned int needed_pio[3] = {
XFER_PIO_0, XFER_PIO_3, XFER_PIO_4
};
int pio = needed_pio[mwdma] - XFER_PIO_0;

control = 3; /* IORDY|TIME1 */

/* If the drive MWDMA is faster than it can do PIO then
we must force PIO into PIO0 */

if (adev->pio_mode < needed_pio[mwdma])
/* Enable DMA timing only */
control |= 8; /* PIO cycles in PIO0 */

if (adev->devno) { /* Slave */
master_data &= 0xFF4F; /* Mask out IORDY|TIME1|DMAONLY */
master_data |= control << 4;
pci_read_config_byte(dev, 0x44, &slave_data);
slave_data &= (ap->port_no ? 0x0f : 0xf0);
/* Load the matching timing */
slave_data |= ((timings[pio][0] << 2) | timings[pio][1]) << (ap->port_no ? 4 : 0);
pci_write_config_byte(dev, 0x44, slave_data);
} else { /* Master */
master_data &= 0xCCF4; /* Mask out IORDY|TIME1|DMAONLY
and master timing bits */
master_data |= control;
master_data |=
(timings[pio][0] << 12) |
(timings[pio][1] << 8);
}

if (ap->udma_mask)
udma_enable &= ~(1 << devid);

pci_write_config_word(dev, master_port, master_data);
/* XFER_PIO_0 is never used currently */
piix_set_timings(ap, adev, pio);
}
/* Don't scribble on 0x48 if the controller does not support UDMA */
if (ap->udma_mask)
pci_write_config_byte(dev, 0x48, udma_enable);

spin_unlock_irqrestore(&piix_lock, flags);
}

/**
Expand Down

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