Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18;
MIME-Version: 1.0
References: <cover.aaf2100bd7da4609f8bcb8216247d4b4e4379639.1590594512.git-series.maxime@cerno.tech>
 <f1b1737fe0665e7191c3d2a3cd9bfafb831866be.1590594512.git-series.maxime@cerno.tech>
In-Reply-To: <f1b1737fe0665e7191c3d2a3cd9bfafb831866be.1590594512.git-series.maxime@cerno.tech>
From:   Eric Anholt <eric@anholt.net>
Date:   Wed, 27 May 2020 12:40:02 -0700
Message-ID: <CADaigPUpH4DuK_FSVGmq-ZPPCtvxOcdq881h9h3NE1_ODJ6tuA@mail.gmail.com>
Subject: Re: [PATCH v3 055/105] drm/vc4: hvs: Introduce a function to get the
 assigned FIFO
To:     Maxime Ripard <maxime@cerno.tech>
Cc:     Nicolas Saenz Julienne <nsaenzjulienne@suse.de>,
        DRI Development <dri-devel@lists.freedesktop.org>,
        linux-rpi-kernel@lists.infradead.org,
        bcm-kernel-feedback-list@broadcom.com,
        linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org,
        Dave Stevenson <dave.stevenson@raspberrypi.com>,
        Tim Gover <tim.gover@raspberrypi.com>,
        Phil Elwell <phil@raspberrypi.com>
Content-Type: text/plain; charset="UTF-8"
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

On Wed, May 27, 2020 at 8:50 AM Maxime Ripard <maxime@cerno.tech> wrote:
>
> At boot time, if we detect that a pixelvalve has been enabled, we need to
> be able to retrieve the HVS channel it has been assigned to so that we can
> disable that channel too. Let's create that function that returns the FIFO
> or an error from a given output.
>
> Signed-off-by: Maxime Ripard <maxime@cerno.tech>
> ---

> +int vc4_hvs_get_fifo_from_output(struct drm_device *dev, unsigned int output)
> +{
> +       struct vc4_dev *vc4 = to_vc4_dev(dev);
> +       u32 reg;
> +       int ret;
> +
> +       switch (output) {
> +       case 0:
> +               return 0;
> +
> +       case 1:
> +               return 1;
> +
> +       case 2:
> +               reg = HVS_READ(SCALER_DISPECTRL);
> +               ret = FIELD_GET(SCALER_DISPECTRL_DSP2_MUX_MASK, reg);
> +               if (ret == 0)
> +                       return 2;
> +
> +               return 0;
> +
> +       case 3:
> +               reg = HVS_READ(SCALER_DISPCTRL);
> +               ret = FIELD_GET(SCALER_DISPCTRL_DSP3_MUX_MASK, reg);
> +               if (ret == 3)
> +                       return -EPIPE;
> +
> +               return ret;
> +
> +       case 4:
> +               reg = HVS_READ(SCALER_DISPEOLN);
> +               ret = FIELD_GET(SCALER_DISPEOLN_DSP4_MUX_MASK, reg);
> +               if (ret == 3)
> +                       return -EPIPE;
> +
> +               return ret;
> +
> +       case 5:
> +               reg = HVS_READ(SCALER_DISPDITHER);
> +               ret = FIELD_GET(SCALER_DISPDITHER_DSP5_MUX_MASK, reg);
> +               if (ret == 3)
> +                       return -EPIPE;

Oh, FIELD_GET is new to me.  Looks like we should replace
VC4_GET_FIELD usage with just using that header, and also
VC4_SET_FIELD with WARN_ON(!FIELD_FIT()); FIELD_PREP.

Could you follow up with that?  Other than that, 54-67 r-b.