On Tue, Sep 27, 2022, at 4:56 PM, Valentin Korenblit wrote:
What happens if you do pairs of read from offset 0, effectivelythe two sequential 32-bit accesses (with OFF0==0 and OFF1==4 seemBut in the mean time I am only half satisfied, because we plan to doIn my example, I had an #ifdef so it would only fall back
twice more accesses than needed _just_ because of a the COMPILE_TEST
constraint.
to 32-bit accesses on the 64-bit register when running an
actual 32-bit kernel, but leaving the 64-bit case efficient. Sorry for my late reply. I've just tested this and unfortunately
to trigger sdma_err. I need to check some waveforms to verify if it
happens right after the first access.
doing a readsl() instead of readql(), obviously with twice the number
of accesses.
It's also possible you have to read from the second word first,
like
u32 *buf;
do {
buf[1] = __raw_readl(reg + 4);
buf[0] = __raw_readl(reg);
buf += 2;
} while (buf < end);
Arnd