Subject: musb bogosity

From: Paul Mundt <[email-masked]>
Date: Fri, 8 Aug 2008 17:27:22 +0900

The musb code currently kills the SH randconfig build (and this will hose
any platform that also selects HAVE_CLK -- a PPC or AVR32 randconfig
would have also hit this eventually), as can be seen here:

http://kisskb.ellerman.id.au/kisskb/buildresult/41095/

This initial failure comes from the fact that musb handily uses "special"
I/O routines that it handily wraps, after having failed at grepping for
other users. Why this driver isn't using ioread/writeXX_rep() is beyond
me, as that's the portable interface we have for doing precisely this
sort of thing, without this bizarre PIO/MMIO wrapper munging that isn't
even going to work on most platforms.

With that ifdef in place, it's on to the next integral build failure:

drivers/usb/musb/musb_core.c: In function 'fifo_setup':
drivers/usb/musb/musb_core.c:1122: error: 'MUSB_C_RAM_BITS' undeclared (first use in this function)
drivers/usb/musb/musb_core.c:1122: error: (Each undeclared identifier is reported only once
drivers/usb/musb/musb_core.c:1122: error: for each function it appears in.)
drivers/usb/musb/musb_core.c: In function 'ep_config_from_table':
drivers/usb/musb/musb_core.c:1246: error: 'MUSB_C_RAM_BITS' undeclared (first use in this function)
drivers/usb/musb/musb_core.c: In function 'musb_remove':
drivers/usb/musb/musb_core.c:2131: warning: unused variable 'ctrl_base'
make[1]: *** [drivers/usb/musb/musb_core.o] Error 1
make: *** [drivers/usb/musb/musb_core.o] Error 2

...

$ git grep MUSB_C_RAM_BITS drivers/usb/musb
drivers/usb/musb/musb_core.c:#define DYN_FIFO_SIZE (1<<(MUSB_C_RAM_BITS+2))
drivers/usb/musb/tusb6010.h:#define MUSB_C_RAM_BITS 12

...

the comment above MUSB_C_RAM_BITS seems to suggest that it's entirely dependent
on the chip, so moving it in to musb_core.c wouldn't be terribly productive. Which
leaves us in a situation where the core is dependent on arbitrary driver
definitions, while the driver itself is obviously only dependent on the core.
Has anyone actually tested this with TUSB6010 support disabled?

A quick grep suggests that blackfin is also going to get bitten by this, so
simply tossing a depends on (ARM && BROKEN) in wouldn't help matters either.

---

diff --git a/drivers/usb/musb/musb_io.h b/drivers/usb/musb/musb_io.h
index 6bbedae..d0f812a 100644
--- a/drivers/usb/musb/musb_io.h
+++ b/drivers/usb/musb/musb_io.h
@@ -37,7 +37,7 @@
 
 #include <linux/io.h>
 
-#ifndef	CONFIG_ARM
+#if !defined(CONFIG_ARM) && !defined(CONFIG_SUPERH)
 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)