On 08.02.2011 15:23, Bartlomiej Zolnierkiewicz wrote:
From ca6c1fbc7d853829524b87a3bcbbb1f67796281c Mon Sep 17 00:00:00 2001
From: Bartlomiej Zolnierkiewicz<bzolnier@xxxxxxxxx>
Date: Tue, 8 Feb 2011 12:39:24 +0100
Subject: [PATCH 02/20] ata_piix: unify code for programming PIO and MWDMA timings
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@xxxxxxxxx>
[...]
diff --git a/drivers/ata/ata_piix.c b/drivers/ata/ata_piix.c
index 0f4856d..c954f91 100644
--- a/drivers/ata/ata_piix.c
+++ b/drivers/ata/ata_piix.c
@@ -696,22 +696,11 @@ 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, 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;
@@ -732,14 +721,18 @@ static void piix_set_piomode(struct ata_port *ap, struct ata_device *adev)
{ 2, 1 },
{ 2, 3 }, };
- if (pio >= 2)
+ if (pio >= 2 || use_mwdma)
The 'use_mwdma' check is actually superfluous...
control |= 1; /* TIME1 enable */
- if (ata_pio_need_iordy(adev))
+ if (ata_pio_need_iordy(adev) || use_mwdma)
control |= 2; /* IE enable */
Why IORDY is enabled for MWDMA has always been beyond me... I understand
that the stupid Intel docs are to be blamed here.
-
/* 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 */
It's not the preferred multi-line comment style:
/*
* bla
* bla
*/
+ if (use_mwdma && adev->pio_mode < (XFER_PIO_0 + pio))
Parens not needed around +.
@@ -803,31 +812,20 @@ 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);
I don't think you should have removed that...
@@ -860,56 +858,20 @@ 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 {
[...]
- if (ap->udma_mask)
- udma_enable &= ~(1 << devid);
This does not seem correct -- you must disable UDMA when programming MWDMA.
-
- 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);
}
/**
WBR, Sergei
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