linux-kernel - Re: [PATCH v2 16/17] drm/vc4: tests: Fail the current test if we access a register

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Date:   Wed, 30 Nov 2022 11:09:59 +0100
From:   Javier Martinez Canillas <javierm@...hat.com>
To:     Maxime Ripard <maxime@...no.tech>, Daniel Vetter <daniel@...ll.ch>,
        Maarten Lankhorst <maarten.lankhorst@...ux.intel.com>,
        Maxime Ripard <mripard@...nel.org>,
        David Airlie <airlied@...il.com>,
        Thomas Zimmermann <tzimmermann@...e.de>
Cc:     dri-devel@...ts.freedesktop.org,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        kunit-dev@...glegroups.com, linux-media@...r.kernel.org,
        linux-kselftest@...r.kernel.org, linaro-mm-sig@...ts.linaro.org,
        Brendan Higgins <brendan.higgins@...ux.dev>,
        Maíra Canal <mairacanal@...eup.net>,
        Dave Stevenson <dave.stevenson@...pberrypi.com>,
        linux-kernel@...r.kernel.org, David Gow <davidgow@...gle.com>
Subject: Re: [PATCH v2 16/17] drm/vc4: tests: Fail the current test if we
 access a register

On 11/28/22 15:53, Maxime Ripard wrote:
> Accessing a register when running under kunit is a bad idea since our
> device is completely mocked.
> 
> Fail the current test if we ever access any of our hardware registers.
> 
> Signed-off-by: Maxime Ripard <maxime@...no.tech>
> ---

[...]

> -#define CRTC_WRITE(offset, val) writel(val, vc4_crtc->regs + (offset))
> -#define CRTC_READ(offset) readl(vc4_crtc->regs + (offset))
> +#define CRTC_WRITE(offset, val)								\
> +	do {										\
> +		kunit_fail_current_test("Accessing a register in a unit test!\n");	\
> +		writel(val, vc4_crtc->regs + (offset));					\
> +	} while (0)
> +
> +#define CRTC_READ(offset)								\
> +	({										\
> +		kunit_fail_current_test("Accessing a register in a unit test!\n");	\
> +		readl(vc4_crtc->regs + (offset));					\
> +	})
> 

Should this be made conditional on whether DRM_VC4_KUNIT_TEST is enabled ? 

That is, just define the simpler macros when is disabled? The kunit_fail_current_test()
is just a no-op if CONFIG_KUNIT isn't enabled, but I think my question still stands.

Reviewed-by: Javier Martinez Canillas <javierm@...hat.com>

-- 
Best regards,

Javier Martinez Canillas
Core Platforms
Red Hat