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From: Wolfram Sang <w.sang@pengutronix.de>
To: linuxppc-embedded@ozlabs.org
Subject: [PATCH] MPC52XX: Don't touch pipelining for MPC5200B
Date: Mon, 18 Aug 2008 11:31:32 +0200	[thread overview]
Message-ID: <20080818093132.GA4282@pengutronix.de> (raw)

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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 <w.sang@pengutronix.de>
---

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 |    3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

Index: playground/arch/powerpc/platforms/52xx/mpc52xx_common.c
===================================================================
--- playground.orig/arch/powerpc/platforms/52xx/mpc52xx_common.c
+++ playground/arch/powerpc/platforms/52xx/mpc52xx_common.c
@@ -99,12 +99,13 @@
 	out_be32(&xlb->master_pri_enable, 0xff);
 	out_be32(&xlb->master_priority, 0x11111111);
 
+#if defined(CONFIG_PPC_MPC5200_BUGFIX)
 	/* Disable XLB pipelining
 	 * (cfr errate 292. We could do this only just before ATA PIO
 	 *  transaction and re-enable it afterwards ...)
 	 */
 	out_be32(&xlb->config, in_be32(&xlb->config) | MPC52xx_XLB_CFG_PLDIS);
-
+#endif
 	iounmap(xlb);
 }
 
-- 
  Dipl.-Ing. Wolfram Sang | http://www.pengutronix.de
 Pengutronix - Linux Solutions for Science and Industry

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             reply	other threads:[~2008-08-18  9:31 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2008-08-18  9:31 Wolfram Sang [this message]
2008-08-18 10:49 ` [PATCH] MPC52XX: Don't touch pipelining for MPC5200B Arnd Bergmann
2008-08-18 14:18   ` [PATCH V2] " Wolfram Sang
2008-08-18 15:57     ` Grant Likely

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