I'd like a sanity check on a change I am considering to
these macros....
I had some difficulty executing these macros
(found in include/asm/processor.h) in a loop, eg:
#define DMA0_BANKS 4
#define DCRN_DMA0_BASE 0x100
#define DCRN_DMA0_CR(bank) (DCRN_DMA0_BASE + (8 * (bank)))
for(i=0;i<DMA0_BANKS;i++){
dma0_cr = mfdcr(DCRN_DMA0_CR(i));
CLEARBITS(dma0_cr, DMA0_CR_PCE);
mtdcr(DCRN_DMA0_CR(i), dma0_cr);
};
compiling results in the assembler error
/tmp/cca8HPJ4.s:282: Error: undefined symbol `i' in operation
Compiling with the -E to see what the pre-processor is generating
--
for(i=0;i< 4 ;i++) {
dma0_cr = ({unsigned int rval;
asm volatile("mfdcr %0," "(0x100 + (8 * (i)))"
: "=r" (rval)); rval;}) ;
( dma0_cr = dma0_cr | 0x00000008 ) ;
asm volatile("mtdcr " "(0x100 + (8 * (i)))" ",%0"
: : "r" ( dma0_cr )) ;
};
Looking at the definition of mtdcr and mfdcr in processor.h
--
#define mfdcr(rn) ({unsigned int rval; \
asm volatile("mfdcr %0," __stringify(rn) \
: "=r" (rval)); rval;})
#define mtdcr(rn, v) asm volatile("mtdcr " __stringify(rn) ",%0" \
: : "r" (v))
I was suspicious that the use of __stringify was buggering up my
index parameter. I made a slight tweak to these macros to take
(rn) as a numeric input param.
#define mfdcr(rn) ({unsigned int rval; \
asm volatile("mfdcr %0, %1" \
: "=r" (rval) \
: "n" (rn)); \
rval;})
#define mtdcr(rn, v) asm volatile("mtdcr %1 ,%0" \
: : "r" (v), "n" (rn));
Testing this morning so far seems to indicate the new version is
working for me, but my usage is fairly limited. Am I missing
anything ??
Cheers,
--
Bep Verberk
verberk at nortelnetworks.com
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