sh: Kill off legacy UBC wakeup cruft.

This code was added for some ancient SH-4 solution engines with peculiar
boot ROMs that did silly things to the UBC MSTP bits. None of these have
been in the wild for years, and these days the clock framework wraps up
the MSTP bits, meaning that the UBC code is one of the few interfaces
that is stomping MSTP bits underneath the clock framework. At this point
the risks far outweigh any benefit this code provided, so just kill it
off.

Signed-off-by: Paul Mundt <[e-mail]>

arch/sh/Kconfig

···
 	default "0x00010000" if PAGE_SIZE_64KB
 	default "0x00000000"
 
-config UBC_WAKEUP
-	bool "Wakeup UBC on startup"
-	depends on CPU_SH4 && !CPU_SH4A
-	help
-	  Selecting this option will wakeup the User Break Controller (UBC) on
-	  startup. Although the UBC is left in an awake state when the processor
-	  comes up, some boot loaders misbehave by putting the UBC to sleep in a
-	  power saving state, which causes issues with things like ptrace().
-
-	  If unsure, say N.
-
 choice
 	prompt "Kernel command line"
 	optional

arch/sh/include/asm/ubc.h

···
 #define BRCR_UBDE		(1 << 0)
 #endif
 
-#ifndef __ASSEMBLY__
-/* arch/sh/kernel/cpu/ubc.S */
-extern void ubc_sleep(void);
-
-#ifdef CONFIG_UBC_WAKEUP
-extern void ubc_wakeup(void);
-#else
-#define ubc_wakeup()	do { } while (0)
-#endif
-#endif
-
 #endif /* __KERNEL__ */
 #endif /* __ASM_SH_UBC_H */

arch/sh/kernel/cpu/Makefile

···
 
 # Common interfaces.
 
-obj-$(CONFIG_UBC_WAKEUP)	+= ubc.o
 obj-$(CONFIG_SH_ADC)		+= adc.o
 obj-$(CONFIG_SH_CLK_CPG)	+= clock-cpg.o
 

arch/sh/kernel/cpu/init.c

···
 	}
 #endif
 
-	/*
-	 * Some brain-damaged loaders decided it would be a good idea to put
-	 * the UBC to sleep. This causes some issues when it comes to things
-	 * like PTRACE_SINGLESTEP or doing hardware watchpoints in GDB.  So ..
-	 * we wake it up and hope that all is well.
-	 */
-#ifdef CONFIG_SUPERH32
-	if (raw_smp_processor_id() == 0)
-		ubc_wakeup();
-#endif
-
 	speculative_execution_init();
 	expmask_init();
 }

arch/sh/kernel/cpu/ubc.S

···
-/*
- * arch/sh/kernel/cpu/ubc.S
- *
- * Set of management routines for the User Break Controller (UBC)
- *
- * Copyright (C) 2002 Paul Mundt
- *
- * This program is free software; you can redistribute it and/or modify it
- * under the terms of the GNU General Public License as published by the
- * Free Software Foundation; either version 2 of the License, or (at your
- * option) any later version.
- */
-#include <linux/linkage.h>
-#include <asm/ubc.h>
-
-#define STBCR2		0xffc00010
-
-ENTRY(ubc_sleep)
-	mov	#0, r0
-
-	mov.l	1f, r1		! Zero out UBC_BBRA ..
-	mov.w	r0, @r1
-
-	mov.l	2f, r1		! .. same for BBRB ..
-	mov.w	r0, @r1
-
-	mov.l	3f, r1		! .. and again for BRCR.
-	mov.w	r0, @r1
-
-	mov.w	@r1, r0		! Dummy read BRCR
-
-	mov.l	4f, r1		! Set MSTP5 in STBCR2
-	mov.b	@r1, r0
-	or	#0x01, r0
-	mov.b	r0, @r1
-
-	mov.b	@r1, r0		! Two dummy reads ..
-	mov.b	@r1, r0
-
-	rts
-	nop
-
-ENTRY(ubc_wakeup)
-	mov.l	4f, r1		! Clear MSTP5
-	mov.b	@r1, r0
-	and	#0xfe, r0
-	mov.b	r0, @r1
-
-	mov.b	@r1, r0		! Two more dummy reads ..
-	mov.b	@r1, r0
-
-	rts
-	nop
-
-1:	.long	UBC_BBRA
-2:	.long	UBC_BBRB
-3:	.long	UBC_BRCR
-4:	.long	STBCR2
-