* [PATCH v3] riscv: Fix udelay in RV32.
@ 2019-05-30 7:01 ` Nick Hu
0 siblings, 0 replies; 4+ messages in thread
From: Nick Hu @ 2019-05-30 7:01 UTC (permalink / raw)
To: greentime, palmer, albert, linux-riscv, linux-kernel, hch
Cc: Nick Hu, green.hu
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 <nickhu@andestech.com>
Reviewed-by: Palmer Dabbelt <palmer@sifive.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
^ permalink raw reply related [flat|nested] 4+ messages in thread
* [PATCH v3] riscv: Fix udelay in RV32.
@ 2019-05-30 7:01 ` Nick Hu
0 siblings, 0 replies; 4+ messages in thread
From: Nick Hu @ 2019-05-30 7:01 UTC (permalink / raw)
To: greentime, palmer, albert, linux-riscv, linux-kernel, hch
Cc: green.hu, Nick Hu
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 <nickhu@andestech.com>
Reviewed-by: Palmer Dabbelt <palmer@sifive.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
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http://lists.infradead.org/mailman/listinfo/linux-riscv
^ permalink raw reply related [flat|nested] 4+ messages in thread
* Re: [PATCH v3] riscv: Fix udelay in RV32.
2019-05-30 7:01 ` Nick Hu
@ 2019-06-11 14:29 ` Paul Walmsley
-1 siblings, 0 replies; 4+ messages in thread
From: Paul Walmsley @ 2019-06-11 14:29 UTC (permalink / raw)
To: Nick Hu
Cc: greentime, palmer, albert, linux-riscv, linux-kernel, hch, green.hu
On Thu, 30 May 2019, Nick Hu 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 <nickhu@andestech.com>
> Reviewed-by: Palmer Dabbelt <palmer@sifive.com>
Thanks, queued for v5.2-rc.
- Paul
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH v3] riscv: Fix udelay in RV32.
@ 2019-06-11 14:29 ` Paul Walmsley
0 siblings, 0 replies; 4+ messages in thread
From: Paul Walmsley @ 2019-06-11 14:29 UTC (permalink / raw)
To: Nick Hu
Cc: greentime, palmer, linux-kernel, hch, green.hu, albert, linux-riscv
On Thu, 30 May 2019, Nick Hu 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 <nickhu@andestech.com>
> Reviewed-by: Palmer Dabbelt <palmer@sifive.com>
Thanks, queued for v5.2-rc.
- Paul
_______________________________________________
linux-riscv mailing list
linux-riscv@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-riscv
^ permalink raw reply [flat|nested] 4+ messages in thread
end of thread, other threads:[~2019-06-11 14:29 UTC | newest]
Thread overview: 4+ messages (download: mbox.gz / follow: Atom feed)
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2019-05-30 7:01 [PATCH v3] riscv: Fix udelay in RV32 Nick Hu
2019-05-30 7:01 ` Nick Hu
2019-06-11 14:29 ` Paul Walmsley
2019-06-11 14:29 ` Paul Walmsley
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