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riscv: Fix udelay in RV32.

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[ Upstream commit d0e1f2110a ]

In RV32, udelay would delay the wrong cycle. When it shifts right
"UDELAY_SHIFT" 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 <nickhu@andestech.com>
Reviewed-by: Palmer Dabbelt <palmer@sifive.com>
[paul.walmsley@sifive.com: fixed minor spelling error]
Signed-off-by: Paul Walmsley <paul.walmsley@sifive.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
This commit is contained in:
Nick Hu 2019-05-30 15:01:17 +08:00 committed by Greg Kroah-Hartman
parent 122c6a71c0
commit b71f312e9b
1 changed files with 1 additions and 1 deletions
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2
arch/riscv/lib/delay.c
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@ -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);