2024-04-15 13:45:50

by Arnd Bergmann

[permalink] [raw]
Subject: [PATCH] clk: sophgo: avoid open-coded 64-bit division

From: Arnd Bergmann <[email protected]>

On 32-bit architectures, the 64-bit division leads to a link failure:

arm-linux-gnueabi-ld: drivers/clk/sophgo/clk-cv18xx-pll.o: in function `fpll_calc_rate':
clk-cv18xx-pll.c:(.text.fpll_calc_rate+0x26): undefined reference to `__aeabi_uldivmod'

This one is not called in a fast path, and there is already another div_u64()
variant used in the same function, so convert it to div64_u64_rem().

Fixes: 80fd61ec4612 ("clk: sophgo: Add clock support for CV1800 SoC")
Signed-off-by: Arnd Bergmann <[email protected]>
---
drivers/clk/sophgo/clk-cv18xx-pll.c | 3 +--
1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/drivers/clk/sophgo/clk-cv18xx-pll.c b/drivers/clk/sophgo/clk-cv18xx-pll.c
index c546dad1791c..29e24098bf5f 100644
--- a/drivers/clk/sophgo/clk-cv18xx-pll.c
+++ b/drivers/clk/sophgo/clk-cv18xx-pll.c
@@ -205,8 +205,7 @@ static unsigned long fpll_calc_rate(unsigned long parent_rate,
unsigned long rate;

dividend <<= PLL_SYN_FACTOR_DOT_POS - 1;
- rate = dividend / factor;
- dividend %= factor;
+ rate = div64_u64_rem(dividend, factor, &dividend);

if (is_full_parent) {
dividend <<= 1;
--
2.39.2



2024-04-15 22:30:29

by Inochi Amaoto

[permalink] [raw]
Subject: Re: [PATCH] clk: sophgo: avoid open-coded 64-bit division

On Mon, Apr 15, 2024 at 03:45:20PM +0200, Arnd Bergmann wrote:
> From: Arnd Bergmann <[email protected]>
>
> On 32-bit architectures, the 64-bit division leads to a link failure:
>
> arm-linux-gnueabi-ld: drivers/clk/sophgo/clk-cv18xx-pll.o: in function `fpll_calc_rate':
> clk-cv18xx-pll.c:(.text.fpll_calc_rate+0x26): undefined reference to `__aeabi_uldivmod'
>
> This one is not called in a fast path, and there is already another div_u64()
> variant used in the same function, so convert it to div64_u64_rem().
>
> Fixes: 80fd61ec4612 ("clk: sophgo: Add clock support for CV1800 SoC")
> Signed-off-by: Arnd Bergmann <[email protected]>

There is already a fix patch:
https://lore.kernel.org/all/IA1PR20MB4953CB4FCCDE82AB25F6880EBB0B2@IA1PR20MB4953.namprd20.prod.outlook.com/

2024-04-17 11:15:14

by Inochi Amaoto

[permalink] [raw]
Subject: Re: [PATCH] clk: sophgo: avoid open-coded 64-bit division

On Tue, Apr 16, 2024 at 06:30:42AM GMT, Inochi Amaoto wrote:
> On Mon, Apr 15, 2024 at 03:45:20PM +0200, Arnd Bergmann wrote:
> > From: Arnd Bergmann <[email protected]>
> >
> > On 32-bit architectures, the 64-bit division leads to a link failure:
> >
> > arm-linux-gnueabi-ld: drivers/clk/sophgo/clk-cv18xx-pll.o: in function `fpll_calc_rate':
> > clk-cv18xx-pll.c:(.text.fpll_calc_rate+0x26): undefined reference to `__aeabi_uldivmod'
> >
> > This one is not called in a fast path, and there is already another div_u64()
> > variant used in the same function, so convert it to div64_u64_rem().
> >
> > Fixes: 80fd61ec4612 ("clk: sophgo: Add clock support for CV1800 SoC")
> > Signed-off-by: Arnd Bergmann <[email protected]>
>
> There is already a fix patch:
> https://lore.kernel.org/all/IA1PR20MB4953CB4FCCDE82AB25F6880EBB0B2@IA1PR20MB4953.namprd20.prod.outlook.com/

Hi Arnd,

I have looked your patch again and think your patch is better
than mine. So I decided to drop my patch and favor yours.

LGTM. And there are some necessary tags.

Reviewed-by: Inochi Amaoto <[email protected]>
Reported-by: kernel test robot <[email protected]>
Closes: https://lore.kernel.org/oe-kbuild-all/[email protected]/
Closes: https://lore.kernel.org/oe-kbuild-all/[email protected]/

2024-04-19 21:38:37

by Stephen Boyd

[permalink] [raw]
Subject: Re: [PATCH] clk: sophgo: avoid open-coded 64-bit division

Quoting Arnd Bergmann (2024-04-15 06:45:20)
> From: Arnd Bergmann <[email protected]>
>
> On 32-bit architectures, the 64-bit division leads to a link failure:
>
> arm-linux-gnueabi-ld: drivers/clk/sophgo/clk-cv18xx-pll.o: in function `fpll_calc_rate':
> clk-cv18xx-pll.c:(.text.fpll_calc_rate+0x26): undefined reference to `__aeabi_uldivmod'
>
> This one is not called in a fast path, and there is already another div_u64()
> variant used in the same function, so convert it to div64_u64_rem().
>
> Fixes: 80fd61ec4612 ("clk: sophgo: Add clock support for CV1800 SoC")
> Signed-off-by: Arnd Bergmann <[email protected]>
> ---

Applied to clk-next