[U-Boot] [PATCH 1/2] net: add Calxeda xgmac driver

Mike Frysinger
2011-12-02T22:14:42Z

On Friday 02 December 2011 17:02:00 Rob Herring wrote:
> On 12/02/2011 03:30 PM, Mike Frysinger wrote:
> > On Friday 02 December 2011 15:21:48 Rob Herring wrote:
> >> --- /dev/null
> >> +++ b/drivers/net/calxedaxgmac.c
> >>
> >> + writel(value, dev->iobase + XGMAC_CORE_CONFIG);
> >
> > you should declare a C struct that represents the hardware's register
> > layout, and then use that rather than iobase+register_offset
>
> Is that a suggestion or u-boot mandate? Because the Linux version of the
> driver does it the current way already, it's certainly done both ways in
> u-boot drivers already and personally I really don't like structs for
> register offsets.

i think Wolfgang would tell you it's a mandate, and code you see using
register offsets are the old style that should get updated. sorry.

> >> + macaddr[1] = readl(dev->iobase + XGMAC_CORE_MACADDR0HI);
> >> + macaddr[0] = readl(dev->iobase + XGMAC_CORE_MACADDR0LO);
> >> + memcpy(dev->enetaddr, macaddr, 6);
> >
> > does the initial mac regs really start off with useful info ?
>
> Yes. It contains the only value that will work.

what i mean is that on embedded peripheral blocks, the device powers on with
blank register settings and the core needs to program them. how did your
device get a mac address already programmed into it ? did something run
before u-boot and initialize the registers ? does the hardware block preseed
the registers itself by talking to some internal storage ? certainly the mac
address isn't programmed into the hardware block itself :).

> >> + sprintf(enetvar, id ? "eth%daddr" : "ethaddr", id);
> >> + eth_setenv_enetaddr(enetvar, dev->enetaddr);
> >
> > NAK: delete this
>
> PXE boot needs the MAC address to generate filenames and gets it from
> the env. See format_mac_pxe function in common/cmd_pxe.c. Should that be
> done differently? The user setting a MAC address on our platform won't
> work, so using the env setting as an override is not valid.

device drivers should not be touching the env. common code takes care of
that. your driver should only be writing dev->enetaddr.
-mike
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