Re: [PATCH 2/3] usb: cp210x: Added in support to get and store part number

[Sergei Shtylyov <sshtylyov@mvista.com>]

Hello.

On 01-05-2012 8:06, Preston Fick wrote:

> This change gets the part number of the device when the driver is loaded and
> stores it in the private portion of the port structure. This addition will
> allow for part specific functionality to be added to the driver if needed.

> Signed-off-by: Preston Fick<preston.fick@silabs.com>
> ---
>   drivers/usb/serial/cp210x.c |   24 ++++++++++++++++++++++++
>   1 files changed, 24 insertions(+), 0 deletions(-)

> diff --git a/drivers/usb/serial/cp210x.c b/drivers/usb/serial/cp210x.c
> index e67ccf3..b3646b8 100644
> --- a/drivers/usb/serial/cp210x.c
> +++ b/drivers/usb/serial/cp210x.c
[...]
> @@ -862,6 +874,7 @@ static int cp210x_startup(struct usb_serial *serial)
>   {
>   	struct cp210x_port_private *port_priv;
>   	int i;
> +	unsigned int partNum;
>
>   	/* cp210x buffers behave strangely unless device is reset */
>   	usb_reset_device(serial->dev);
> @@ -876,6 +889,17 @@ static int cp210x_startup(struct usb_serial *serial)
>   		    serial->interface->cur_altsetting->desc.bInterfaceNumber;
>
>   		usb_set_serial_port_data(serial->port[i], port_priv);
> +
> +		/* Get the 1-byte part number of the cp210x device */
> +		usb_control_msg(serial->dev,

    This may involve DMA...

> +			usb_rcvctrlpipe(serial->dev, 0),
> +			CP210X_VENDOR_SPECIFIC,
> +			REQTYPE_DEVICE_TO_HOST,
> +			CP210X_GET_PARTNUM,
> +			port_priv->bInterfaceNumber,
> +			&partNum, 1,

    You can't do DMA to a buffer situated on stack. You should kmalloc() the 
buffer.

> +			USB_CTRL_GET_TIMEOUT);
> +		port_priv->bPartNumber = partNum&  0xFF;
>   	}
>
>   	return 0;

WBR, Sergei