Re: [PATCH] [POWERPC] Xilinx: hwicap driver

["Grant Likely" <grant.likely@secretlab.ca>]

On 1/31/08, Stephen Neuendorffer <stephen.neuendorffer@xilinx.com> wrote:
> This includes code for new fifo-based xps_hwicap in addition to the
> older opb_hwicap, which has a significantly different interface.  The
> common code between the two drivers is largely shared.
>
> Significant differences exists between this driver and what is
> supported in the EDK drivers.  In particular, most of the
> architecture-specific code for reconfiguring individual FPGA resources
> has been removed.  This functionality is likely better provided in a
> user-space support library.  In addition, read and write access is
> supported.  In addition, although the xps_hwicap cores support
> interrupt-driver mode, this driver only supports polled operation, in
> order to make the code simpler, and since the interrupt processing
> overhead is likely to slow down the throughput under Linux.
>
> Signed-off-by: Stephen Neuendorffer <stephen.neuendorffer@xilinx.com>
>
> Fixed to add spinlocks, and a few style issues.

You're probably better off using a semaphore, or more specifically a
MUTEX, to protect the whole fop instead of a spin lock and the flags.
The semantics are simpler if do it with a mutex and the function can
sleep while holding it.

Cheers,
g.