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Message-ID: <6118cb58-cdfa-458d-a034-d0422d79ae45@linaro.org>
Date:   Tue, 17 Oct 2023 09:13:30 +0200
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From:   Neil Armstrong <neil.armstrong@linaro.org>
Reply-To: neil.armstrong@linaro.org
Subject: Re: [PATCH] crypto: qcom: add HW_RANDOM dependency
Content-Language: en-US, fr
To:     Arnd Bergmann <arnd@kernel.org>,
        Herbert Xu <herbert@gondor.apana.org.au>,
        "David S. Miller" <davem@davemloft.net>,
        Om Prakash Singh <quic_omprsing@quicinc.com>,
        Bjorn Andersson <quic_bjorande@quicinc.com>
Cc:     Arnd Bergmann <arnd@arndb.de>, linux-crypto@vger.kernel.org,
        linux-kernel@vger.kernel.org
References: <20231016200324.757455-1-arnd@kernel.org>
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In-Reply-To: <20231016200324.757455-1-arnd@kernel.org>
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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>