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

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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@xxxxxxxxxxxxxx> 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@xxxxxxxxxxxxxx>
---
  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@xxxxxxxxxxxx>

+                       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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