[U-Boot] [PATCH 1/2] TI: netdev: add driver for cpsw ethernet device

Kumar Nath, Chandan chandan.nath at ti.com
Fri Nov 11 16:12:17 CET 2011



> -----Original Message-----
> From: Tom Rini [mailto:tom.rini at gmail.com]
> Sent: Friday, November 11, 2011 8:19 PM
> To: Kumar Nath, Chandan
> Cc: u-boot at lists.denx.de; Chemparathy, Cyril
> Subject: Re: [U-Boot] [PATCH 1/2] TI: netdev: add driver for cpsw
> ethernet device
> 
> On Thu, Nov 10, 2011 at 11:01 PM, Kumar Nath, Chandan
> <chandan.nath at ti.com> wrote:
> >
> >
> >> -----Original Message-----
> >> From: Tom Rini [mailto:tom.rini at gmail.com]
> >> Sent: Thursday, November 10, 2011 8:11 PM
> >> To: Kumar Nath, Chandan
> >> Cc: u-boot at lists.denx.de; Chemparathy, Cyril
> >> Subject: Re: [U-Boot] [PATCH 1/2] TI: netdev: add driver for cpsw
> >> ethernet device
> >>
> >> On Wed, Nov 9, 2011 at 10:47 PM, Kumar Nath, Chandan
> >> <chandan.nath at ti.com> wrote:
> >> >> -----Original Message-----
> >> >> From: Tom Rini [mailto:tom.rini at gmail.com]
> >> >> Sent: Friday, October 21, 2011 9:09 PM
> >> >> To: Kumar Nath, Chandan
> >> >> Cc: u-boot at lists.denx.de; Chemparathy, Cyril
> >> >> Subject: Re: [U-Boot] [PATCH 1/2] TI: netdev: add driver for cpsw
> >> >> ethernet device
> >> >>
> >> >> On Fri, Oct 21, 2011 at 12:02 AM, Chandan Nath
> <chandan.nath at ti.com>
> >> >> wrote:
> >> >> > From: Cyril Chemparathy <cyril at ti.com>
> >> >> >
> >> >> > CPSW is an on-chip ethernet switch that is found on various
> SoCs
> >> from
> >> >> Texas
> >> >> > Instruments.  This patch adds a simple driver (based on the
> Linux
> >> >> driver) for
> >> >> > this hardware module.
> >> >>
> >> >> Have you made the driver safe with dcache enabled?
> >> >
> >> > No, driver is not made safe with dcache enabled. Can you please
> tell
> >> me
> >> > why I need to enable dcache.
> >>
> >> Because we really want to enable the dcache for performance reasons.
> >> Given that to enable dcache on am335x we just need:
> >> #ifndef CONFIG_SYS_DCACHE_OFF
> >> void enable_caches(void)
> >> {
> >>         /* Enable D-cache. I-cache is already enabled in start.S */
> >>         dcache_enable();
> >> }
> >> #endif
> >>
> >> We really want to not add drivers that aren't cache safe, especially
> >> when it's not a lot of work to do so.
> >>
> >
> > I tried enabling dcache by adding above code. But when I executed
> dhcp command,
> > it was not able to find any IP address and keeps trying infinitely.
> 
> Correct.  The cpsw driver in u-boot is not cache coherent, which is
> what I'm asking you to fix.  Looking at the patches to make the
> davinci emac driver cache cohernet might be of some help here.
> 

Ok, I will look into this and update you.

> --
> Tom


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