On Thu, May 30, 2019 at 02:49:10PM +0800, Nick Chun-Ming Hu(胡峻銘) wrote:
> In RV32, udelay would delay the wrong cycle. When it shifts right
> "UDELAY_SHITFT" bits, it either delays 0 cycle or 1 cycle. It only works
> correctly in RV64. Because the 'ucycles' always needs to be 64 bits
> variable.
>
> Signed-off-by: Nick Hu <nic...@andestech.com>
> ---
> arch/riscv/lib/delay.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/arch/riscv/lib/delay.c b/arch/riscv/lib/delay.c
> index dce8ae24c6d3..ee6853c1e341 100644
> --- a/arch/riscv/lib/delay.c
> +++ b/arch/riscv/lib/delay.c
> @@ -88,7 +88,7 @@ EXPORT_SYMBOL(__delay);
>
> void udelay(unsigned long usecs)
> {
> - unsigned long ucycles = usecs * lpj_fine * UDELAY_MULT;
> + u64 ucycles = (u64)usecs * lpj_fine * UDELAY_MULT;
>
> if (unlikely(usecs > MAX_UDELAY_US)) {
> __delay((u64)usecs * riscv_timebase / 1000000ULL);
> --
> 2.17.0
>
Hi All, I forgot to add "Reviewed-by: Palmer Dabbelt <pal...@sifive.com>".
I will send another patch.
Sorry.
