Re: drivers/usb/musb/musb_io.h

[Felipe Balbi <me@felipebalbi.com>]

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On Fri, Aug 15, 2008 at 07:05:31PM -0700, David Brownell wrote:
> On Friday 15 August 2008, David Brownell wrote:
> > Someone commented that this is what caused creation of
> > the mmio_insl() family of routines ...
> > 
> > ... but I notice that at least on ARM (current primary home
> > for this driver!) those calls don't end up using optimized
> > code. Since those optimimzed loops are a *big* win in terms
> > of performance -- using LDM/STM to burst memory acccess to/from
> > registers -- I'd rather not go that way for now.
> 
> Oh, and worth remembering:  *WHEN* a clean solution for this
> is available, it should be usable in the NAND code.  And surely
> in other places which sometimes need PIO access to a FIFO...
> 
> I was surprised to see that 16% improvement in read performance
> with an 8-bit NAND device, just by switching from code looking
> like generic mmio_insb() over to __raw_readsb().  Better IMO to
> have the faster code be what the NAND core uses by default, than
> to need to modify every platform's NAND driver to do that.

Sure, I'll have to keep an eye on what's going on include/linux/io.h

Attached is a new patch, added also ppc since they also provide those
read/write calls.

-- 
balbi

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From e6df3ab0b49e5a52c0b0b089d38efba97dd2f870 Mon Sep 17 00:00:00 2001
From: Felipe Balbi <felipe.balbi@nokia.com>
Date: Fri, 15 Aug 2008 10:51:56 +0300
Subject: [PATCH] musb: io: only define read/write stubs if they're not defined yet

For those archs which don't provide read/write friends we
provide our own implementation so musb driver won't break
compilation.

This is temporary fix until a better solution comes from
upstream. Idealy, <linux/io.h> would provide those calls
if the architecture did not provide them yet. In that case
being possible to remove all those stubs from musb_io.h

Signed-off-by: Felipe Balbi <felipe.balbi@nokia.com>
---
 drivers/usb/musb/musb_io.h |    4 +++-
 1 files changed, 3 insertions(+), 1 deletions(-)

diff --git a/drivers/usb/musb/musb_io.h b/drivers/usb/musb/musb_io.h
index 6bbedae..223f0a5 100644
--- a/drivers/usb/musb/musb_io.h
+++ b/drivers/usb/musb/musb_io.h
@@ -37,7 +37,9 @@
 
 #include <linux/io.h>
 
-#ifndef	CONFIG_ARM
+#if !defined(CONFIG_ARM) && !defined(CONFIG_SUPERH) \
+	&& !defined(CONFIG_AVR32) && !defined(CONFIG_PPC32) \
+	&& !defined(CONFIG_PPC64)
 static inline void readsl(const void __iomem *addr, void *buf, int len)
 	{ insl((unsigned long)addr, buf, len); }
 static inline void readsw(const void __iomem *addr, void *buf, int len)
-- 
1.6.0.rc3.10.g5a13c


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