Re: [PATCH] PXA27x UDC driver.

[Rodolfo Giometti <giometti@enneenne.com>]

On Thu, Jun 28, 2007 at 02:29:49PM -0700, Andrew Morton wrote:
> >
> > +
> > +static int
> > +write_packet(volatile u32 * uddr, struct pxa27x_request *req, unsigned max)
> 
> Please review Documentation/volatile-considered-harmful.txt

The attibute volatile here is necessary in order to avoid getting the
following warnings from the compiler:

     CC      drivers/usb/gadget/pxa27x_udc.o
   drivers/usb/gadget/pxa27x_udc.c: In function `write_ep0_fifo':
   drivers/usb/gadget/pxa27x_udc.c:512: warning: passing arg 1 of `write_packet' discards qualifiers from pointer target type
   drivers/usb/gadget/pxa27x_udc.c: In function `pxa27x_ep_alloc':
   drivers/usb/gadget/pxa27x_udc.c:1206: warning: assignment discards qualifiers from pointer target type
   drivers/usb/gadget/pxa27x_udc.c:1207: warning: assignment discards qualifiers from pointer target type
   drivers/usb/gadget/pxa27x_udc.c:1208: warning: assignment discards qualifiers from pointer target type
   drivers/usb/gadget/pxa27x_udc.c:1209: warning: assignment discards qualifiers from pointer target type
   drivers/usb/gadget/pxa27x_udc.c: At top level:
   drivers/usb/gadget/pxa27x_udc.c:2159: warning: initialization discards qualifiers from pointer target type
   drivers/usb/gadget/pxa27x_udc.c:2160: warning: initialization discards qualifiers from pointer target type

This because the variables reg_* are assigned as:

   .reg_udccsr = &UDCCSR0

where UDCCSR0 are defined as:

   #define UDCCSR0         __REG(0x40600100) /* UDC Control/Status register - Endpoint 0 */

and:

   define __REG(x)	(*((volatile u32 *)io_p2v(x)))

Do you know how I can resolve this?

Thanks in advance,

Rodolfo

-- 

GNU/Linux Solutions                  e-mail:    giometti@enneenne.com
Linux Device Driver                             giometti@gnudd.com
Embedded Systems                     		giometti@linux.it
UNIX programming                     phone:     +39 349 2432127