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[ARM] Provide a method to alter the control register 

i.MX needs to tweak the control register to support CPU frequency
scaling.  Rather than have folk blindly try and change the control
register by writing to it and then wondering why it doesn't work,
provide a method (which is safe for UP only, and therefore only
available for UP) to achieve this.

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
This commit is contained in:
Russell King 2006-12-13 18:33:53 +00:00 committed by Russell King
parent 02828845dd
commit 47fd705287
1 changed files with 20 additions and 0 deletions
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20
include/asm-arm/system.h
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@ -173,6 +173,26 @@ static inline void set_copro_access(unsigned int val)
extern unsigned long cr_no_alignment; /* defined in entry-armv.S */
extern unsigned long cr_alignment; /* defined in entry-armv.S */
#ifndef CONFIG_SMP
static inline void adjust_cr(unsigned long mask, unsigned long set)
{
unsigned long flags, cr;
mask &= ~CR_A;
set &= mask;
local_irq_save(flags);
cr_no_alignment = (cr_no_alignment & ~mask) | set;
cr_alignment = (cr_alignment & ~mask) | set;
set_cr((get_cr() & ~mask) | set);
local_irq_restore(flags);
}
#endif
#define UDBG_UNDEFINED (1 << 0)
#define UDBG_SYSCALL (1 << 1)
#define UDBG_BADABORT (1 << 2)