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From:   Dave Emett <david.emett@broadcom.com>
Date:   Fri, 8 Mar 2019 18:18:43 +0000
Message-ID: <CAApk1dVbYaxBi7LVNgvVBabCZaWp7=yJ5YDMq3ozz4-peZnaGA@mail.gmail.com>
Subject: Re: [PATCH v4 2/2] drm/v3d: Add support for V3D v4.2.
To:     Eric Anholt <eric@anholt.net>
Cc:     dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org,
        Thomas Spurden <thomas.spurden@broadcom.com>
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On Fri, 8 Mar 2019 at 17:43, Eric Anholt <eric@anholt.net> wrote:
>
> No compatible string for it yet, just the version-dependent changes.
> They've now tied the hub and the core interrupt lines into a single
> interrupt line coming out of the block.  It also turns out I made a
> mistake in modeling the V3D v3.3 and v4.1 bridge as a part of V3D
> itself -- the bridge is going away in favor of an external reset
> controller in a larger HW module.
>
> v2: Use consistent checks for whether we're on 4.2, and fix a leak in
>     an error path.
> v3: Use more general means of determining if the current 4.2 changes
>     are in place, as apparently other platforms may switch back (noted
>     by Dave).  Update the binding doc.
> v4: Improve error handling for IRQ init.
>
> Signed-off-by: Eric Anholt <eric@anholt.net>

Reviewed-by: Dave Emett <david.emett@broadcom.com>

> ---
>  .../devicetree/bindings/gpu/brcm,bcm-v3d.txt  | 11 +++--
>  drivers/gpu/drm/v3d/v3d_drv.c                 | 21 +++++++--
>  drivers/gpu/drm/v3d/v3d_drv.h                 |  2 +
>  drivers/gpu/drm/v3d/v3d_gem.c                 | 12 ++++-
>  drivers/gpu/drm/v3d/v3d_irq.c                 | 45 ++++++++++++++-----
>  5 files changed, 71 insertions(+), 20 deletions(-)
>
> diff --git a/Documentation/devicetree/bindings/gpu/brcm,bcm-v3d.txt b/Documentation/devicetree/bindings/gpu/brcm,bcm-v3d.txt
> index c907aa8dd755..b2df82b44625 100644
> --- a/Documentation/devicetree/bindings/gpu/brcm,bcm-v3d.txt
> +++ b/Documentation/devicetree/bindings/gpu/brcm,bcm-v3d.txt
> @@ -6,15 +6,20 @@ For V3D 2.x, see brcm,bcm-vc4.txt.
>  Required properties:
>  - compatible:  Should be "brcm,7268-v3d" or "brcm,7278-v3d"
>  - reg:         Physical base addresses and lengths of the register areas
> -- reg-names:   Names for the register areas.  The "hub", "bridge", and "core0"
> +- reg-names:   Names for the register areas.  The "hub" and "core0"
>                   register areas are always required.  The "gca" register area
> -                 is required if the GCA cache controller is present.
> +                 is required if the GCA cache controller is present.  The
> +                 "bridge" register area is required if an external reset
> +                 controller is not present.
>  - interrupts:  The interrupt numbers.  The first interrupt is for the hub,
> -                 while the following interrupts are for the cores.
> +                 while the following interrupts are separate interrupt lines
> +                 for the cores (if they don't share the hub's interrupt).
>                   See bindings/interrupt-controller/interrupts.txt
>
>  Optional properties:
>  - clocks:      The core clock the unit runs on
> +- resets:      The reset line for v3d, if not using a mapping of the bridge
> +                 See bindings/reset/reset.txt
>
>  v3d {
>         compatible = "brcm,7268-v3d";
> diff --git a/drivers/gpu/drm/v3d/v3d_drv.c b/drivers/gpu/drm/v3d/v3d_drv.c
> index f9906cac7a88..89b7567d550f 100644
> --- a/drivers/gpu/drm/v3d/v3d_drv.c
> +++ b/drivers/gpu/drm/v3d/v3d_drv.c
> @@ -19,6 +19,7 @@
>  #include <linux/of_platform.h>
>  #include <linux/platform_device.h>
>  #include <linux/pm_runtime.h>
> +#include <linux/reset.h>
>  #include <drm/drm_fb_cma_helper.h>
>  #include <drm/drm_fb_helper.h>
>
> @@ -264,10 +265,6 @@ static int v3d_platform_drm_probe(struct platform_device *pdev)
>         v3d->pdev = pdev;
>         drm = &v3d->drm;
>
> -       ret = map_regs(v3d, &v3d->bridge_regs, "bridge");
> -       if (ret)
> -               goto dev_free;
> -
>         ret = map_regs(v3d, &v3d->hub_regs, "hub");
>         if (ret)
>                 goto dev_free;
> @@ -282,6 +279,22 @@ static int v3d_platform_drm_probe(struct platform_device *pdev)
>         v3d->cores = V3D_GET_FIELD(ident1, V3D_HUB_IDENT1_NCORES);
>         WARN_ON(v3d->cores > 1); /* multicore not yet implemented */
>
> +       v3d->reset = devm_reset_control_get_exclusive(dev, NULL);
> +       if (IS_ERR(v3d->reset)) {
> +               ret = PTR_ERR(v3d->reset);
> +
> +               if (ret == -EPROBE_DEFER)
> +                       goto dev_free;
> +
> +               v3d->reset = NULL;
> +               ret = map_regs(v3d, &v3d->bridge_regs, "bridge");
> +               if (ret) {
> +                       dev_err(dev,
> +                               "Failed to get reset control or bridge regs\n");
> +                       goto dev_free;
> +               }
> +       }
> +
>         if (v3d->ver < 41) {
>                 ret = map_regs(v3d, &v3d->gca_regs, "gca");
>                 if (ret)
> diff --git a/drivers/gpu/drm/v3d/v3d_drv.h b/drivers/gpu/drm/v3d/v3d_drv.h
> index bb58ecb9d9c5..b5efac7894ca 100644
> --- a/drivers/gpu/drm/v3d/v3d_drv.h
> +++ b/drivers/gpu/drm/v3d/v3d_drv.h
> @@ -33,6 +33,7 @@ struct v3d_dev {
>          * and revision.
>          */
>         int ver;
> +       bool single_irq_line;
>
>         struct device *dev;
>         struct platform_device *pdev;
> @@ -41,6 +42,7 @@ struct v3d_dev {
>         void __iomem *bridge_regs;
>         void __iomem *gca_regs;
>         struct clk *clk;
> +       struct reset_control *reset;
>
>         /* Virtual and DMA addresses of the single shared page table. */
>         volatile u32 *pt;
> diff --git a/drivers/gpu/drm/v3d/v3d_gem.c b/drivers/gpu/drm/v3d/v3d_gem.c
> index 0a83268dec0c..449d01ea54a0 100644
> --- a/drivers/gpu/drm/v3d/v3d_gem.c
> +++ b/drivers/gpu/drm/v3d/v3d_gem.c
> @@ -6,6 +6,7 @@
>  #include <linux/module.h>
>  #include <linux/platform_device.h>
>  #include <linux/pm_runtime.h>
> +#include <linux/reset.h>
>  #include <linux/device.h>
>  #include <linux/io.h>
>  #include <linux/sched/signal.h>
> @@ -70,7 +71,7 @@ v3d_idle_gca(struct v3d_dev *v3d)
>  }
>
>  static void
> -v3d_reset_v3d(struct v3d_dev *v3d)
> +v3d_reset_by_bridge(struct v3d_dev *v3d)
>  {
>         int version = V3D_BRIDGE_READ(V3D_TOP_GR_BRIDGE_REVISION);
>
> @@ -90,6 +91,15 @@ v3d_reset_v3d(struct v3d_dev *v3d)
>                                  V3D_TOP_GR_BRIDGE_SW_INIT_1_V3D_CLK_108_SW_INIT);
>                 V3D_BRIDGE_WRITE(V3D_TOP_GR_BRIDGE_SW_INIT_1, 0);
>         }
> +}
> +
> +static void
> +v3d_reset_v3d(struct v3d_dev *v3d)
> +{
> +       if (v3d->reset)
> +               reset_control_reset(v3d->reset);
> +       else
> +               v3d_reset_by_bridge(v3d);
>
>         v3d_init_hw_state(v3d);
>  }
> diff --git a/drivers/gpu/drm/v3d/v3d_irq.c b/drivers/gpu/drm/v3d/v3d_irq.c
> index 29d746cfce57..b8aea2dfbe82 100644
> --- a/drivers/gpu/drm/v3d/v3d_irq.c
> +++ b/drivers/gpu/drm/v3d/v3d_irq.c
> @@ -27,6 +27,9 @@
>                             V3D_HUB_INT_MMU_CAP |       \
>                             V3D_HUB_INT_TFUC))
>
> +static irqreturn_t
> +v3d_hub_irq(int irq, void *arg);
> +
>  static void
>  v3d_overflow_mem_work(struct work_struct *work)
>  {
> @@ -112,6 +115,12 @@ v3d_irq(int irq, void *arg)
>         if (intsts & V3D_INT_GMPV)
>                 dev_err(v3d->dev, "GMP violation\n");
>
> +       /* V3D 4.2 wires the hub and core IRQs together, so if we &
> +        * didn't see the common one then check hub for MMU IRQs.
> +        */
> +       if (v3d->single_irq_line && status == IRQ_NONE)
> +               return v3d_hub_irq(irq, arg);
> +
>         return status;
>  }
>
> @@ -159,7 +168,7 @@ v3d_hub_irq(int irq, void *arg)
>  int
>  v3d_irq_init(struct v3d_dev *v3d)
>  {
> -       int ret, core;
> +       int irq1, ret, core;
>
>         INIT_WORK(&v3d->overflow_mem_work, v3d_overflow_mem_work);
>
> @@ -170,17 +179,29 @@ v3d_irq_init(struct v3d_dev *v3d)
>                 V3D_CORE_WRITE(core, V3D_CTL_INT_CLR, V3D_CORE_IRQS);
>         V3D_WRITE(V3D_HUB_INT_CLR, V3D_HUB_IRQS);
>
> -       ret = devm_request_irq(v3d->dev, platform_get_irq(v3d->pdev, 0),
> -                              v3d_hub_irq, IRQF_SHARED,
> -                              "v3d_hub", v3d);
> -       if (ret)
> -               goto fail;
> -
> -       ret = devm_request_irq(v3d->dev, platform_get_irq(v3d->pdev, 1),
> -                              v3d_irq, IRQF_SHARED,
> -                              "v3d_core0", v3d);
> -       if (ret)
> -               goto fail;
> +       irq1 = platform_get_irq(v3d->pdev, 1);
> +       if (irq1 == -EPROBE_DEFER)
> +               return irq1;
> +       if (irq1 > 0) {
> +               ret = devm_request_irq(v3d->dev, irq1,
> +                                      v3d_irq, IRQF_SHARED,
> +                                      "v3d_core0", v3d);
> +               if (ret)
> +                       goto fail;
> +               ret = devm_request_irq(v3d->dev, platform_get_irq(v3d->pdev, 0),
> +                                      v3d_hub_irq, IRQF_SHARED,
> +                                      "v3d_hub", v3d);
> +               if (ret)
> +                       goto fail;
> +       } else {
> +               v3d->single_irq_line = true;
> +
> +               ret = devm_request_irq(v3d->dev, platform_get_irq(v3d->pdev, 0),
> +                                      v3d_irq, IRQF_SHARED,
> +                                      "v3d", v3d);
> +               if (ret)
> +                       goto fail;
> +       }
>
>         v3d_irq_enable(v3d);
>         return 0;
> --
> 2.20.1
>