[PATCH 02/86] ata_piix: unify code for programming PIO and MWDMA timings

Bartlomiej Zolnierkiewicz
2009-11-25T17:03:19Z

From: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>
Subject: [PATCH] ata_piix: unify code for programming PIO and MWDMA timings

It results in ~2% decrease in the driver LOC count and also ~2%
decrease in the driver binary size (as measured on x86-32).

This change should be safe as this is how we have been doing
things in IDE piix host driver for years.

Fix piix_set_piomode() documentation while at it.

Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>
---
drivers/ata/ata_piix.c | 112 ++++++++++++++++---------------------------------
1 file changed, 37 insertions(+), 75 deletions(-)

Index: b/drivers/ata/ata_piix.c
===================================================================
--- a/drivers/ata/ata_piix.c
+++ b/drivers/ata/ata_piix.c
@@ -666,22 +666,11 @@ static int piix_pata_prereset(struct ata

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, bool use_mwdma)
{
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;
@@ -702,14 +691,18 @@ static void piix_set_piomode(struct ata_
{ 2, 1 },
{ 2, 3 }, };

- if (pio >= 2)
+ if (pio >= 2 || use_mwdma)
control |= 1; /* TIME1 enable */
- if (ata_pio_need_iordy(adev))
+ if (ata_pio_need_iordy(adev) || use_mwdma)
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 (use_mwdma && adev->pio_mode < (XFER_PIO_0 + pio))
+ /* Enable DMA timing only */
+ control |= 8; /* PIO cycles in PIO0 */

spin_lock_irqsave(&piix_lock, flags);

@@ -757,6 +750,22 @@ static void piix_set_piomode(struct ata_
}

/**
+ * 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, 0);
+}
+
+/**
* do_pata_set_dmamode - Initialize host controller PATA PIO timings
* @ap: Port whose timings we are configuring
* @adev: Drive in question
@@ -772,31 +781,20 @@ static void do_pata_set_dmamode(struct a
{
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
@@ -829,56 +827,20 @@ static void do_pata_set_dmamode(struct a
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);
+ piix_set_timings(ap, adev, pio, 1);
}
- /* 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);
}

/**