Re: [PATCH] crypto: qcom: add HW_RANDOM dependency

[Neil Armstrong <neil.armstrong@linaro.org>]

On 16/10/2023 22:02, Arnd Bergmann wrote:
> From: Arnd Bergmann <arnd@arndb.de>
> 
> The driver now calls into the hwrng subsystem and causes a link failure if that
> is not reachable:
> 
> x86_64-linux-ld: vmlinux.o: in function `qcom_rng_probe':
> qcom-rng.c:(.text+0xfefc7e): undefined reference to `devm_hwrng_register'
> 
> Add a Kconfig dependency as we have for the pure hw_random drivers. I see
> that there are some other crypto drivers that instead use 'select HW_RANDOM',
> but those seem to be mistakes as that may lead to circular dependencies,
> and a simple driver should not force-enable an entire subsytem.
> 
> Fixes: f29cd5bb64c25 ("crypto: qcom-rng - Add hw_random interface support")
> Signed-off-by: Arnd Bergmann <arnd@arndb.de>
> ---
>   drivers/crypto/Kconfig | 1 +
>   1 file changed, 1 insertion(+)
> 
> diff --git a/drivers/crypto/Kconfig b/drivers/crypto/Kconfig
> index c761952f0dc6d..79c3bb9c99c3b 100644
> --- a/drivers/crypto/Kconfig
> +++ b/drivers/crypto/Kconfig
> @@ -601,6 +601,7 @@ config CRYPTO_DEV_QCE_SW_MAX_LEN
>   config CRYPTO_DEV_QCOM_RNG
>   	tristate "Qualcomm Random Number Generator Driver"
>   	depends on ARCH_QCOM || COMPILE_TEST
> +	depends on HW_RANDOM
>   	select CRYPTO_RNG
>   	help
>   	  This driver provides support for the Random Number

Reviewed-by: Neil Armstrong <neil.armstrong@linaro.org>