Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752780Ab1BTNoi (ORCPT ); Sun, 20 Feb 2011 08:44:38 -0500 Received: from mail-ey0-f180.google.com ([209.85.215.180]:61630 "EHLO mail-ey0-f180.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751447Ab1BTNog (ORCPT ); Sun, 20 Feb 2011 08:44:36 -0500 X-Greylist: delayed 408 seconds by postgrey-1.27 at vger.kernel.org; Sun, 20 Feb 2011 08:44:35 EST Message-ID: <4D6118DC.80505@ru.mvista.com> Date: Sun, 20 Feb 2011 16:36:28 +0300 From: Sergei Shtylyov User-Agent: Mozilla/5.0 (Windows; U; Windows NT 5.1; en-GB; rv:1.9.2.13) Gecko/20101207 Thunderbird/3.1.7 MIME-Version: 1.0 To: Bartlomiej Zolnierkiewicz CC: linux-ide@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH 02/20] ata_piix: unify code for programming PIO and MWDMA timings References: <20110208122314.19110.4092.sendpatchset@linux-mhg7.site> <20110208122346.19110.8441.sendpatchset@linux-mhg7.site> In-Reply-To: <20110208122346.19110.8441.sendpatchset@linux-mhg7.site> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 4428 Lines: 139 On 08.02.2011 15:23, Bartlomiej Zolnierkiewicz wrote: > From ca6c1fbc7d853829524b87a3bcbbb1f67796281c Mon Sep 17 00:00:00 2001 > From: Bartlomiej Zolnierkiewicz > 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 [...] > 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 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/