[Nouveau] [PATCH 7/7] clock/nva3: Pause the GPU before reclocking

Ilia Mirkin imirkin at alum.mit.edu
Thu Aug 21 05:25:10 PDT 2014


On Thu, Aug 21, 2014 at 7:45 AM, Roy Spliet <rspliet at eclipso.eu> wrote:
> Signed-off-by: Roy Spliet <rspliet at eclipso.eu>
> ---
>  .../gpu/drm/nouveau/core/include/subdev/clock.h    |  3 ++
>  drivers/gpu/drm/nouveau/core/subdev/clock/nva3.c   | 45 ++++++++++++++++++++++
>  drivers/gpu/drm/nouveau/core/subdev/clock/nvaa.c   | 30 ++++-----------
>  3 files changed, 55 insertions(+), 23 deletions(-)
>
> diff --git a/drivers/gpu/drm/nouveau/core/include/subdev/clock.h b/drivers/gpu/drm/nouveau/core/include/subdev/clock.h
> index 676b49e..52e65b8 100644
> --- a/drivers/gpu/drm/nouveau/core/include/subdev/clock.h
> +++ b/drivers/gpu/drm/nouveau/core/include/subdev/clock.h
> @@ -146,6 +146,9 @@ int nv04_clock_pll_prog(struct nouveau_clock *, u32 reg1,
>  int nva3_clock_pll_calc(struct nouveau_clock *, struct nvbios_pll *,
>                         int clk, struct nouveau_pll_vals *);
>
> +int nva3_clock_pre(struct nouveau_clock *clk, unsigned long *flags);
> +void nva3_clock_post(struct nouveau_clock *clk, unsigned long *flags);
> +
>  int nouveau_clock_ustate(struct nouveau_clock *, int req);
>  int nouveau_clock_astate(struct nouveau_clock *, int req, int rel);
>  int nouveau_clock_dstate(struct nouveau_clock *, int req, int rel);
> diff --git a/drivers/gpu/drm/nouveau/core/subdev/clock/nva3.c b/drivers/gpu/drm/nouveau/core/subdev/clock/nva3.c
> index 14a5060..cd31cf3 100644
> --- a/drivers/gpu/drm/nouveau/core/subdev/clock/nva3.c
> +++ b/drivers/gpu/drm/nouveau/core/subdev/clock/nva3.c
> @@ -23,6 +23,7 @@
>   *          Roy Spliet
>   */
>
> +#include <engine/fifo.h>
>  #include <subdev/bios.h>
>  #include <subdev/bios/pll.h>
>  #include <subdev/timer.h>
> @@ -293,6 +294,41 @@ calc_host(struct nva3_clock_priv *priv, struct nouveau_cstate *cstate)
>         return ret;
>  }
>
> +int
> +nva3_clock_pre(struct nouveau_clock *clk, unsigned long *flags)
> +{
> +       struct nouveau_fifo *pfifo = nouveau_fifo(clk);
> +
> +       /* halt and idle execution engines */
> +       nv_mask(clk, 0x020060, 0x00070000, 0x00000000);
> +       nv_mask(clk, 0x002504, 0x00000001, 0x00000001);
> +       /* Wait until the interrupt handler is finished */
> +       if (!nv_wait(clk, 0x000100, 0xffffffff, 0x00000000))
> +               return -EBUSY;

So this will return with the fifo and whatever 20060 controls all
blocked. That seems bad, unless you guarantee that _post gets run no
matter what.

> +
> +       if (pfifo)
> +               pfifo->pause(pfifo, flags);
> +
> +       if (!nv_wait(clk, 0x002504, 0x00000010, 0x00000010))
> +               return -EIO;
> +       if (!nv_wait(clk, 0x00251c, 0x0000003f, 0x0000003f))
> +               return -EIO;
> +
> +       return 0;
> +}
> +
> +void
> +nva3_clock_post(struct nouveau_clock *clk, unsigned long *flags)
> +{
> +       struct nouveau_fifo *pfifo = nouveau_fifo(clk);
> +
> +       if (pfifo)
> +               pfifo->start(pfifo, flags);
> +
> +       nv_mask(clk, 0x002504, 0x00000001, 0x00000000);
> +       nv_mask(clk, 0x020060, 0x00070000, 0x00040000);
> +}
> +
>  static void
>  disable_clk_src(struct nva3_clock_priv *priv, u32 src)
>  {
> @@ -421,6 +457,12 @@ nva3_clock_prog(struct nouveau_clock *clk)
>  {
>         struct nva3_clock_priv *priv = (void *)clk;
>         struct nva3_clock_info *core = &priv->eng[nv_clk_src_core];
> +       int ret;
> +       unsigned long flags;
> +
> +       ret = nva3_clock_pre(clk, &flags);
> +       if (ret)
> +               return ret;

The fifo may be paused. Do you have to run _post unconditionally here
perhaps? goto's make this sort of thing really simple (+ return ret
instead of return 0).

>
>         if (core->pll)
>                 prog_core(priv, nv_clk_src_core_intm);
> @@ -430,6 +472,9 @@ nva3_clock_prog(struct nouveau_clock *clk)
>         prog_clk(priv, 0x20, nv_clk_src_disp);
>         prog_clk(priv, 0x21, nv_clk_src_vdec);
>         prog_host(priv);
> +
> +       nva3_clock_post(clk, &flags);
> +
>         return 0;
>  }
>
> diff --git a/drivers/gpu/drm/nouveau/core/subdev/clock/nvaa.c b/drivers/gpu/drm/nouveau/core/subdev/clock/nvaa.c
> index 6a65fc9..fa91d2a 100644
> --- a/drivers/gpu/drm/nouveau/core/subdev/clock/nvaa.c
> +++ b/drivers/gpu/drm/nouveau/core/subdev/clock/nvaa.c
> @@ -299,25 +299,13 @@ static int
>  nvaa_clock_prog(struct nouveau_clock *clk)
>  {
>         struct nvaa_clock_priv *priv = (void *)clk;
> -       struct nouveau_fifo *pfifo = nouveau_fifo(clk);
> +       u32 pllmask = 0, mast;
>         unsigned long flags;
> -       u32 pllmask = 0, mast, ptherm_gate;
> -       int ret = -EBUSY;
> -
> -       /* halt and idle execution engines */
> -       ptherm_gate = nv_mask(clk, 0x020060, 0x00070000, 0x00000000);
> -       nv_mask(clk, 0x002504, 0x00000001, 0x00000001);
> -       /* Wait until the interrupt handler is finished */
> -       if (!nv_wait(clk, 0x000100, 0xffffffff, 0x00000000))
> -               goto resume;

As above, you've killed the 'resume' logic...

> -
> -       if (pfifo)
> -               pfifo->pause(pfifo, &flags);
> +       int ret;
>
> -       if (!nv_wait(clk, 0x002504, 0x00000010, 0x00000010))
> -               goto resume;
> -       if (!nv_wait(clk, 0x00251c, 0x0000003f, 0x0000003f))
> -               goto resume;
> +       ret = nva3_clock_pre(clk, &flags);
> +       if (ret)
> +               return ret;
>
>         /* First switch to safe clocks: href */
>         mast = nv_mask(clk, 0xc054, 0x03400e70, 0x03400640);
> @@ -378,12 +366,6 @@ nvaa_clock_prog(struct nouveau_clock *clk)
>         ret = 0;
>
>  resume:
> -       if (pfifo)
> -               pfifo->start(pfifo, &flags);
> -
> -       nv_mask(clk, 0x002504, 0x00000001, 0x00000000);
> -       nv_wr32(clk, 0x020060, ptherm_gate);
> -
>         /* Disable some PLLs and dividers when unused */
>         if (priv->csrc != nv_clk_src_core) {
>                 nv_wr32(clk, 0x4040, 0x00000000);
> @@ -395,6 +377,8 @@ resume:
>                 nv_mask(clk, 0x4020, 0x80000000, 0x00000000);
>         }
>
> +       nva3_clock_post(clk, &flags);
> +
>         return ret;
>  }
>
> --
> 1.9.3
>
>
>
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