pxa2xx PCMCIA timing issue on iPAQ H5550

Recently I've been trying to get working PCMCIA interface on H5000 ipaq
series, using dual PCMCIA sleeve.  So far things work correctly, but I had
to do one modification to drivers/pcmcia/pxa2xx_base.c to get the interface
working with orinoco gold PCMCIA card (wired pcnet_cs ethernet card worked
even without this modification).

The issue has something to do with assert time on PCMCIA bus, but I'm not
really sure what -- I found the working value just by trial&error approach.
 I'm not sure how is the assert value in pxa2xx_mcxx_asst calculated (I
know, simple formula, but the reason why is it calculated that way is not
obvious for me), neither that my modification is correct.  It just works
with iPAQ.

Cc: Russell King <rmk@arm.linux.org.uk>
Cc: Richard Purdie <rpurdie@rpsys.net>
Cc: Dominik Brodowski <linux@dominikbrodowski.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/drivers/pcmcia/pxa2xx_base.c b/drivers/pcmcia/pxa2xx_base.c
index dca9f8549b32503c081498cc5a8f159c4d72c192..874923fcb2f9615fee7f34715c15e12b57d93742 100644 (file)
--- a/drivers/pcmcia/pxa2xx_base.c
+++ b/drivers/pcmcia/pxa2xx_base.c
@@ -58,7 +58,7 @@ static inline u_int pxa2xx_mcxx_asst(u_int pcmcia_cycle_ns,
                                     u_int mem_clk_10khz)
 {
        u_int code = pcmcia_cycle_ns * mem_clk_10khz;
-       return (code / 300000) + ((code % 300000) ? 1 : 0) - 1;
+       return (code / 300000) + ((code % 300000) ? 1 : 0) + 1;
 }
 
 static inline u_int pxa2xx_mcxx_setup(u_int pcmcia_cycle_ns,