Re: [PATCH] drm/rockchip: vop: power off until vop standby take effect

[Mark yao <mark.yao@rock-chips.com>]

On 2015年02月02日 10:07, Daniel Kurtz wrote:
> Hi Mark, Heiko,
>
> On Sat, Jan 31, 2015 at 4:41 PM, Mark Yao <mark.yao@rock-chips.com> wrote:
>> Vop standby will take effect end of current frame,
>> if dsp_hold_valid_irq happen, it means vop standby complete.
>>
>> we must wait standby complete when we want to disable aclk,
>> if not, memory bus maybe dead.
>>
>> Signed-off-by: Mark Yao <mark.yao@rock-chips.com>
>> ---
>>   drivers/gpu/drm/rockchip/rockchip_drm_vop.c |   76 ++++++++++++++++++++++-----
>>   1 file changed, 63 insertions(+), 13 deletions(-)
>>
>> diff --git a/drivers/gpu/drm/rockchip/rockchip_drm_vop.c b/drivers/gpu/drm/rockchip/rockchip_drm_vop.c
>> index fb25836..47ea61f 100644
>> --- a/drivers/gpu/drm/rockchip/rockchip_drm_vop.c
>> +++ b/drivers/gpu/drm/rockchip/rockchip_drm_vop.c
>> @@ -89,6 +89,7 @@ struct vop {
>>          /* mutex vsync_ work */
>>          struct mutex vsync_mutex;
>>          bool vsync_work_pending;
>> +       struct completion dsp_hold_completion;
>>
>>          const struct vop_data *data;
>>
>> @@ -382,6 +383,34 @@ static bool is_alpha_support(uint32_t format)
>>          }
>>   }
>>
>> +static void vop_dsp_hold_valid_irq_enable(struct vop *vop)
>> +{
>> +       unsigned long flags;
>> +
>> +       BUG_ON(!vop->is_enabled);
> Re: Heiko "use a WARN_ON":
>
> If the VOP clock is off, then the system will just hang when trying to
> write the VOP register so in this case, BUG_ON gives a more reliable
> crash dump than the hang.
   In this way, you are right, if vop clocks is disabled, write vop 
register will hang system, and the WARN_ON
crash dump may be have no chance to print.
>    
>> +
>> +       spin_lock_irqsave(&vop->irq_lock, flags);
>> +
>> +       vop_mask_write(vop, INTR_CTRL0, DSP_HOLD_VALID_INTR_MASK,
>> +                      DSP_HOLD_VALID_INTR_EN(1));
>> +
>> +       spin_unlock_irqrestore(&vop->irq_lock, flags);
>> +}
>> +
>> +static void vop_dsp_hold_valid_irq_disable(struct vop *vop)
>> +{
>> +       unsigned long flags;
>> +
>> +       BUG_ON(!vop->is_enabled);
>> +
>> +       spin_lock_irqsave(&vop->irq_lock, flags);
>> +
>> +       vop_mask_write(vop, INTR_CTRL0, DSP_HOLD_VALID_INTR_MASK,
>> +                      DSP_HOLD_VALID_INTR_EN(0));
>> +
>> +       spin_unlock_irqrestore(&vop->irq_lock, flags);
>> +}
>> +
>>   static void vop_enable(struct drm_crtc *crtc)
>>   {
>>          struct vop *vop = to_vop(crtc);
>> @@ -454,26 +483,36 @@ static void vop_disable(struct drm_crtc *crtc)
>>
>>          drm_vblank_off(crtc->dev, vop->pipe);
>>
>> -       disable_irq(vop->irq);
>> -
>>          /*
>> -        * TODO: Since standby doesn't take effect until the next vblank,
>> -        * when we turn off dclk below, the vop is probably still active.
>> +        * Vop standby will take effect until end of current frame,
> "Vop standby will take effect at end of current frame"
OK
>> +        * if dsp hold valid irq happen, it means standby complete.
>> +        *
>> +        * we must wait standby complete when we want to disable aclk,
>> +        * if not, memory bus maybe dead.
>>           */
>> +       reinit_completion(&vop->dsp_hold_completion);
>> +       vop_dsp_hold_valid_irq_enable(vop);
>> +
>>          spin_lock(&vop->reg_lock);
>>
>>          VOP_CTRL_SET(vop, standby, 1);
>>
>>          spin_unlock(&vop->reg_lock);
>>
>> +       wait_for_completion(&vop->dsp_hold_completion);
>> +
>> +       vop_dsp_hold_valid_irq_disable(vop);
>> +
>> +       disable_irq(vop->irq);
>> +
>>          vop->is_enabled = false;
>> +
>>          /*
>> -        * disable dclk to stop frame scan, so we can safely detach iommu,
>> +        * vop standby complete, so iommu detach is safe.
>>           */
>> -       clk_disable(vop->dclk);
>> -
>>          rockchip_drm_dma_detach_device(vop->drm_dev, vop->dev);
>>
>> +       clk_disable(vop->dclk);
>>          clk_disable(vop->aclk);
>>          clk_disable(vop->hclk);
>>   }
>> @@ -1086,6 +1125,7 @@ static irqreturn_t vop_isr(int irq, void *data)
>>          struct vop *vop = data;
>>          uint32_t intr0_reg, active_irqs;
>>          unsigned long flags;
>> +       int ret = IRQ_NONE;
>>
>>          /*
>>           * INTR_CTRL0 register has interrupt status, enable and clear bits, we
>> @@ -1104,15 +1144,24 @@ static irqreturn_t vop_isr(int irq, void *data)
>>          if (!active_irqs)
>>                  return IRQ_NONE;
>>
>> -       /* Only Frame Start Interrupt is enabled; other irqs are spurious. */
>> -       if (!(active_irqs & FS_INTR)) {
>> -               DRM_ERROR("Unknown VOP IRQs: %#02x\n", active_irqs);
>> -               return IRQ_NONE;
>> +       if (active_irqs & DSP_HOLD_VALID_INTR) {
>> +               if (!completion_done(&vop->dsp_hold_completion))
> Why is this "completion_done" check needed?
> I guess it doesn't help, but isn't strictly needed, since the
> dsp_hold_completion is a one shot, right?
Right, the DSP_HOLD_VALID_INTR only happen when standby complete, one 
standby one irq.

Mark
> In any case, this should work as it is, so:
>
> Reviewed-by: Daniel Kurtz <djkurtz@chromium.org>
>
>> +                       complete(&vop->dsp_hold_completion);
>> +               active_irqs &= ~DSP_HOLD_VALID_INTR;
>> +               ret = IRQ_HANDLED;
>>          }
>>
>> -       drm_handle_vblank(vop->drm_dev, vop->pipe);
>> +       if (active_irqs & FS_INTR) {
>> +               drm_handle_vblank(vop->drm_dev, vop->pipe);
>> +               active_irqs &= ~FS_INTR;
>> +               ret = (vop->vsync_work_pending) ? IRQ_WAKE_THREAD : IRQ_HANDLED;
>> +       }
>>
>> -       return (vop->vsync_work_pending) ? IRQ_WAKE_THREAD : IRQ_HANDLED;
>> +       /* Unhandled irqs are spurious. */
>> +       if (active_irqs)
>> +               DRM_ERROR("Unknown VOP IRQs: %#02x\n", active_irqs);
>> +
>> +       return ret;
>>   }
>>
>>   static int vop_create_crtc(struct vop *vop)
>> @@ -1194,6 +1243,7 @@ static int vop_create_crtc(struct vop *vop)
>>                  goto err_cleanup_crtc;
>>          }
>>
>> +       init_completion(&vop->dsp_hold_completion);
>>          crtc->port = port;
>>          vop->pipe = drm_crtc_index(crtc);
>>          rockchip_register_crtc_funcs(drm_dev, &private_crtc_funcs, vop->pipe);
>> --
>> 1.7.9.5
>>
>>
>
>


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