[PATCH 3.8.y] staging: comedi: 8255_pci: fix for newer PCI-DIO48H

[Kamal Mostafa]

On Mon, 2014-01-20 at 15:48 +0000, Ian Abbott wrote:
> based on upstream commit 0283f7a100882684ad32b768f9f1ad81658a0b92
> 
> At some point, Measurement Computing / ComputerBoards redesigned the
> PCI-DIO48H to use a PLX PCI interface chip instead of an AMCC chip.
> This meant they had to put their hardware registers in the PCI BAR 2
> region instead of PCI BAR 1.  Unfortunately, they kept the same PCI
> device ID for the new design.  This means the driver recognizes the
> newer cards, but doesn't work (and is likely to screw up the local
> configuration registers of the PLX chip) because it's using the wrong
> region.
> 
> Since  the PCI subvendor and subdevice IDs were both zero on the old
> design, but are the same as the vendor and device on the new design, we
> can tell the old design and new design apart easily enough.  To avoid
> adding extra data to `pci_8255_boards[]`, treat the board as a special
> case in `pci_8255_auto_attach[]`.  It's safer to use the fact that the
> PCI BAR 2 region will have non-zero length only on the newer design, so
> use that fact to distinguish them.
> 
> Signed-off-by: Ian Abbott <abbotti at mev.co.uk>
> Cc: kernel-team at lists.ubuntu.com


Thanks very much for the backport Ian.  It is queued up for
3.8.y-stable.

 -Kamal


> ---
>  drivers/staging/comedi/drivers/8255_pci.c | 20 +++++++++++++++++---
>  1 file changed, 17 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/staging/comedi/drivers/8255_pci.c b/drivers/staging/comedi/drivers/8255_pci.c
> index e0a7952..92ee23e 100644
> --- a/drivers/staging/comedi/drivers/8255_pci.c
> +++ b/drivers/staging/comedi/drivers/8255_pci.c
> @@ -122,7 +122,7 @@ static const struct pci_8255_boardinfo pci_8255_boards[] = {
>  		.name		= "cb_pci-dio48h",
>  		.vendor		= PCI_VENDOR_ID_CB,
>  		.device		= PCI_DEVICE_ID_CB_PCIDIO48H,
> -		.dio_badr	= 1,
> +		.dio_badr	= 1,	/* only for older boards */
>  		.n_8255		= 2,
>  	}, {
>  		.name		= "cb_pci-dio96h",
> @@ -224,6 +224,7 @@ static int pci_8255_auto_attach(struct comedi_device *dev,
>  	unsigned long len;
>  	int ret;
>  	int i;
> +	int dio_badr;
>  
>  	board = pci_8255_find_boardinfo(dev, pcidev);
>  	if (!board)
> @@ -239,8 +240,21 @@ static int pci_8255_auto_attach(struct comedi_device *dev,
>  	ret = comedi_pci_enable(pcidev, dev->board_name);
>  	if (ret)
>  		return ret;
> -	iobase = pci_resource_start(pcidev, board->dio_badr);
> -	len = pci_resource_len(pcidev, board->dio_badr);
> +	dio_badr = board->dio_badr;
> +	/*
> +	 * For Measurement Computing / ComputerBoards PCI-DIO48H, use the
> +	 * PCI BAR 2 region, if non-zero length, else use the PCI BAR 1 region
> +	 * from the board entry.  This is because the board was redesigned to
> +	 * use a different PCI interface chip, with the user registers in a
> +	 * different PCI BAR region.
> +	 */
> +	if (pcidev->vendor == PCI_VENDOR_ID_CB &&
> +	    pcidev->device == PCI_DEVICE_ID_CB_PCIDIO48H &&
> +	    pci_resource_len(pcidev, 2))
> +		dio_badr = 2;
> +
> +	iobase = pci_resource_start(pcidev, dio_badr);
> +	len = pci_resource_len(pcidev, dio_badr);
>  
>  	if (board->is_mmio) {
>  		devpriv->mmio_base = ioremap(iobase, len);

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