* [PATCH v2] riscv: Fix udelay in RV32.
@ 2019-05-30 6:49 ` Nick Hu
0 siblings, 0 replies; 4+ messages in thread
From: Nick Hu @ 2019-05-30 6:49 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>
---
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 v2] riscv: Fix udelay in RV32.
@ 2019-05-30 6:49 ` Nick Hu
0 siblings, 0 replies; 4+ messages in thread
From: Nick Hu @ 2019-05-30 6:49 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>
---
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 v2] riscv: Fix udelay in RV32.
2019-05-30 6:49 ` Nick Hu
@ 2019-05-30 6:54 ` Nick Hu
-1 siblings, 0 replies; 4+ messages in thread
From: Nick Hu @ 2019-05-30 6:54 UTC (permalink / raw)
To: Greentime Ying-Han Hu(胡英漢),
palmer, albert, linux-riscv, linux-kernel, hch
Cc: green.hu
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 <nickhu@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 <palmer@sifive.com>".
I will send another patch.
Sorry.
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH v2] riscv: Fix udelay in RV32.
@ 2019-05-30 6:54 ` Nick Hu
0 siblings, 0 replies; 4+ messages in thread
From: Nick Hu @ 2019-05-30 6:54 UTC (permalink / raw)
To: Greentime Ying-Han Hu(胡英漢),
palmer, albert, linux-riscv, linux-kernel, hch
Cc: green.hu
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 <nickhu@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 <palmer@sifive.com>".
I will send another patch.
Sorry.
_______________________________________________
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
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2019-05-30 6:49 [PATCH v2] riscv: Fix udelay in RV32 Nick Hu
2019-05-30 6:49 ` Nick Hu
2019-05-30 6:54 ` Nick Hu
2019-05-30 6:54 ` Nick Hu
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