Re: [PATCH 1/2] soc: qcom: stats: fix 64-bit division

Uwe Kleine-König
2023-12-06T14:17:20Z

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Hallo Arnd,

On Wed, Dec 06, 2023 at 01:37:06PM +0100, Arnd Bergmann wrote:
> Unguarded 64-bit division is not allowed on 32-bit kernels because this
> is very slow. The result of trying anyway is a link failure:
>
> arm-linux-gnueabi-ld: drivers/soc/qcom/qcom_stats.o: in function `qcom_ddr_stats_show':
> qcom_stats.c:(.text+0x334): undefined reference to `__aeabi_uldivmod'
>
> As this function is only used for debugging and not performance critical,
> rewrite it to use div_u64() instead. ARCH_TIMER_FREQ is a multiple of
> MSEC_PER_SEC anyway, so there is no loss in precisison.

Maybe add this information in a comment?

We have

#define ARCH_TIMER_FREQ 19200000

so it's a multiple of MSEC_PER_SEC (= 1000) indeed.

Reviewed-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>

Best regards
Uwe

--
Pengutronix e.K. | Uwe Kleine-König |
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