lkml.org 
[lkml]   [2007]   [Jul]   [14]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH 1/3] Blackfin ethernet driver: on chip ethernet MAC controller driver
On 7/14/07, Michael Buesch <mb@bu3sch.de> wrote:
> On Saturday 14 July 2007 21:49:21 Mike Frysinger wrote:
> > On 7/14/07, Michael Buesch <mb@bu3sch.de> wrote:
> > > On Saturday 14 July 2007 20:49:53 Bryan Wu wrote:
> > > > +static int __init bf537mac_probe(struct net_device *dev)
> > > > +{
> > > > + struct bf537mac_local *lp = netdev_priv(dev);
> > > > + int retval;
> > > > +
> > > > + /* Grab the MAC address in the MAC */
> > > > + *(u32 *) (&(dev->dev_addr[0])) = bfin_read_EMAC_ADDRLO();
> > > > + *(u16 *) (&(dev->dev_addr[4])) = (u16) bfin_read_EMAC_ADDRHI();
> > >
> > > Endianess broken.
> > >
> > > > +struct dma_config_reg {
> > > > + unsigned short b_DMA_EN:1; /* Bit 0 : DMA Enable */
> > > > + unsigned short b_WNR:1; /* Bit 1 : DMA Direction */
> > > > + unsigned short b_WDSIZE:2; /* Bit 2 & 3 : DMA Tranfer Word size */
> > > > + unsigned short b_DMA2D:1; /* Bit 4 : DMA Mode 2D or 1D */
> > > > + unsigned short b_RESTART:1; /* Bit 5 : Retain the FIFO */
> > > > + unsigned short b_DI_SEL:1; /* Bit 6 : Data Interrupt Timing Select */
> > > > + unsigned short b_DI_EN:1; /* Bit 7 : Data Interrupt Enable */
> > > > + unsigned short b_NDSIZE:4; /* Bit 8 to 11 : Flex descriptor Size */
> > > > + unsigned short b_FLOW:3; /* Bit 12 to 14 : FLOW */
> > > > +};
> > >
> > > This is most likely not endianess safe.
> >
> > do we really need to care about this ? this is a driver for a MAC
> > which can only be found on Blackfin processors and Blackfin itself is
> > only little endian.
>
> Well, this bitfield _might_ be OK (although I don't like bitfields
> at all), but the above pointer casting stuff should really use
> leXX_to_cpu. It's so easy to use and it is easier to read and
> maintain the code afterwards.

i think that's arguable ... i dont see how:
a = foo(b);
is easier to read than:
a = b;
but it is easy to use ... i guess my point was more along the lines of
wasting further time auditing a driver for endianness issues that will
never actually be an issue.
-mike
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/

\
 
 \ /
  Last update: 2007-07-14 22:41    [from the cache]
©2003-2011 Jasper Spaans