On Sat, 2007-07-14 at 16:38 -0400, Mike Frysinger wrote:
> On 7/14/07, Michael Buesch <[EMAIL PROTECTED]> wrote:
> > On Saturday 14 July 2007 21:49:21 Mike Frysinger wrote:
> > > On 7/14/07, Michael Buesch <[EMAIL PROTECTED]> 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.
Sometimes by doing this you catch bugs you didn't see before. It's a
good thing to do generally. Does sparse with endianness check show
errors? You may want to fix those.
Dan
> -mike
> -
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