----- Original Message ----
> From: Wolfram Sang <[EMAIL PROTECTED]>
> To: Arnd Bergmann <[EMAIL PROTECTED]>
> Cc: linuxppc-embedded@ozlabs.org
> Sent: Monday, August 18, 2008 9:18:31 AM
> Subject: [PATCH V2] MPC52XX: Don't touch pipelining for MPC5200B
>
>
> MPC5200 needs to have pipelining disabled for ATA to work. MPC5200B does not.
> So, for the latter, don't touch the original setting from the bootloader.
>
> Signed-off-by: Wolfram Sang
> ---
> Hello Arnd,
>
> On Mon, Aug 18, 2008 at 12:49:36PM +0200, Arnd Bergmann wrote:
>
> > Please make this a run-time conditional instead of compile-time.
> Like this?
>
> ..................................................................
>
> This needs some testing IMHO. Most configs in U-Boot tend to enable
> pipelining,
> which then used to be disabled by the kernel. So, on the one hand, this change
> would enable what is originally wanted; on the other hand, systems may run
> under a new configuration and need to be checked for regressions. Especially
> as
> there can be puzzling effects, like for one setup here, FEC only works
> reliably
> with pipelining enabled.
>
> arch/powerpc/platforms/52xx/mpc52xx_common.c | 7 +++++--
> 1 file changed, 5 insertions(+), 2 deletions(-)
>
> Index: arch/powerpc/platforms/52xx/mpc52xx_common.c
> ===================================================================
> --- arch/powerpc/platforms/52xx/mpc52xx_common.c.orig
> +++ arch/powerpc/platforms/52xx/mpc52xx_common.c
> @@ -99,11 +99,14 @@
> out_be32(&xlb->master_pri_enable, 0xff);
> out_be32(&xlb->master_priority, 0x11111111);
>
> - /* Disable XLB pipelining
> + /*
> + * Disable XLB pipelining
> * (cfr errate 292. We could do this only just before ATA PIO
> * transaction and re-enable it afterwards ...)
> + * Not needed on MPC5200B.
> */
> - out_be32(&xlb->config, in_be32(&xlb->config) | MPC52xx_XLB_CFG_PLDIS);
> + if ((mfspr(SPRN_SVR) & MPC5200_SVR_MASK) == MPC5200_SVR)
> + out_be32(&xlb->config, in_be32(&xlb->config) |
> MPC52xx_XLB_CFG_PLDIS);
>
> iounmap(xlb);
> }
>
> --
> Dipl.-Ing. Wolfram Sang | http://www.pengutronix.de
> Pengutronix - Linux Solutions for Science and Industry
Hi
Since this bug is ATA specific, shouldn't this code be conditioned by
CONFIG_IDE ?
Thanks
-roger
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