Re: [PATCH 2/2] ide: clear bmdma status in ide_intr() for Intel controllers (revised #3)

[Sergei Shtylyov <sshtylyov@ru.mvista.com>]

Hello.

Albert Lee wrote:

> patch 2/2 (revised):
> - Fix drive->waiting_for_dma to work with CDB-intr devices.
> - Do the dma status clearing in ide_intr() and add a new hwif->ide_dma_clear_irq for Intel controllers.

> Signed-off-by: Albert Lee <albertcc@tw.ibm.com>
> ---

> Calling hwif->ide_dma_clear_irq for all controllers looks risky.

    I'm not sure why it's so risky...

> Revised to do it only for the Intel controllers.
> (If any other adapters need it, we may add it later.)

> Patch against 2.6.20-rc6. Tested ok on my ICH4 and pdc20275 adapters.
> Please review/apply, thanks.

> diff -Nrup 01_remove_from_ide_cd/drivers/ide/ide-cd.c 02_add_to_ide_intr/drivers/ide/ide-cd.c
> --- 01_remove_from_ide_cd/drivers/ide/ide-cd.c	2007-01-29 17:23:34.000000000 +0800
> +++ 02_add_to_ide_intr/drivers/ide/ide-cd.c	2007-01-29 17:23:58.000000000 +0800
> @@ -923,6 +923,10 @@ static ide_startstop_t cdrom_start_packe
>  		HWIF(drive)->OUTB(drive->ctl, IDE_CONTROL_REG);
>   
>  	if (CDROM_CONFIG_FLAGS (drive)->drq_interrupt) {
> +		/* waiting for CDB interrupt, not DMA yet. */
> +		if (info->dma)
> +			drive->waiting_for_dma = 0;
> +
>  		/* packet command */
>  		ide_execute_command(drive, WIN_PACKETCMD, handler, ATAPI_WAIT_PC, cdrom_timer_expiry);
>  		return ide_started;
> @@ -965,6 +969,10 @@ static ide_startstop_t cdrom_transfer_pa
>  		/* Check for errors. */
>  		if (cdrom_decode_status(drive, DRQ_STAT, NULL))
>  			return ide_stopped;
> +
> +		/* Ok, next interrupt will be DMA interrupt. */
> +		if (info->dma)
> +			drive->waiting_for_dma = 1;
>  	} else {
>  		/* Otherwise, we must wait for DRQ to get set. */
>  		if (ide_wait_stat(&startstop, drive, DRQ_STAT,
> diff -Nrup 01_remove_from_ide_cd/drivers/ide/ide-dma.c 02_add_to_ide_intr/drivers/ide/ide-dma.c
> --- 01_remove_from_ide_cd/drivers/ide/ide-dma.c	2006-11-30 05:57:37.000000000 +0800
> +++ 02_add_to_ide_intr/drivers/ide/ide-dma.c	2007-01-29 17:23:58.000000000 +0800
> @@ -650,6 +650,20 @@ static int __ide_dma_test_irq(ide_drive_
>  			drive->name, __FUNCTION__);
>  	return 0;
>  }
> +
> +void __ide_dma_clear_irq(ide_drive_t *drive)
> +{
> +	ide_hwif_t *hwif = HWIF(drive);
> +	u8 dma_stat;
> +
> +	/* clear the INTR & ERROR bits */
> +	dma_stat = hwif->INB(hwif->dma_status);
> +	/* Should we force the bit as well ? */
> +	hwif->OUTB(dma_stat, hwif->dma_status);
> +}
> +
> +EXPORT_SYMBOL_GPL(__ide_dma_clear_irq);
> +
>  #endif /* CONFIG_BLK_DEV_IDEDMA_PCI */
>  
>  int __ide_dma_bad_drive (ide_drive_t *drive)
> diff -Nrup 01_remove_from_ide_cd/drivers/ide/ide-io.c 02_add_to_ide_intr/drivers/ide/ide-io.c
> --- 01_remove_from_ide_cd/drivers/ide/ide-io.c	2006-11-30 05:57:37.000000000 +0800
> +++ 02_add_to_ide_intr/drivers/ide/ide-io.c	2007-01-29 17:23:58.000000000 +0800
> @@ -1644,6 +1644,18 @@ irqreturn_t ide_intr (int irq, void *dev
>  	}
>  	hwgroup->handler = NULL;
>  	del_timer(&hwgroup->timer);
> +
> +	/* Some controllers might set DMA INTR no matter DMA or PIO;
> +	 * bmdma status might need to be cleared even for
> +	 * PIO interrupts to prevent spurious/lost irq.
> +	 */
> +	if (hwif->ide_dma_clear_irq && !(drive->waiting_for_dma))
> +		/* ide_dma_end() needs bmdma status for error checking.
> +		 * So, skip clearing bmdma status here and leave it
> +		 * to ide_dma_end() if this is dma interrupt.
> +		 */
> +		hwif->ide_dma_clear_irq(drive);
> +
>  	spin_unlock(&ide_lock);
>  
>  	if (drive->unmask)
> diff -Nrup 01_remove_from_ide_cd/drivers/ide/ide.c 02_add_to_ide_intr/drivers/ide/ide.c
> --- 01_remove_from_ide_cd/drivers/ide/ide.c	2007-01-29 17:19:48.000000000 +0800
> +++ 02_add_to_ide_intr/drivers/ide/ide.c	2007-01-29 17:23:58.000000000 +0800
> @@ -503,6 +503,7 @@ static void ide_hwif_restore(ide_hwif_t 
>  	hwif->ide_dma_on		= tmp_hwif->ide_dma_on;
>  	hwif->ide_dma_off_quietly	= tmp_hwif->ide_dma_off_quietly;
>  	hwif->ide_dma_test_irq		= tmp_hwif->ide_dma_test_irq;
> +	hwif->ide_dma_clear_irq		= tmp_hwif->ide_dma_clear_irq;
>  	hwif->ide_dma_host_on		= tmp_hwif->ide_dma_host_on;
>  	hwif->ide_dma_host_off		= tmp_hwif->ide_dma_host_off;
>  	hwif->ide_dma_lostirq		= tmp_hwif->ide_dma_lostirq;
> diff -Nrup 01_remove_from_ide_cd/drivers/ide/pci/piix.c 02_add_to_ide_intr/drivers/ide/pci/piix.c
> --- 01_remove_from_ide_cd/drivers/ide/pci/piix.c	2007-01-29 17:23:34.000000000 +0800
> +++ 02_add_to_ide_intr/drivers/ide/pci/piix.c	2007-01-29 17:23:58.000000000 +0800
> @@ -483,6 +483,7 @@ static void __devinit init_hwif_piix(ide
>  	if (!hwif->dma_base)
>  		return;
>  
> +	hwif->ide_dma_clear_irq = &__ide_dma_clear_irq;

    If this handler is only called by single driver, why it's not defined locally?

>  	hwif->atapi_dma = 1;
>  	hwif->ultra_mask = 0x3f;
>  	hwif->mwdma_mask = 0x06;

MBR, Sergei