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[PATCH v1 2/4] xlnx_dp: Introduce a vblank signal

frederic.konrad@xilinx.com posted 4 patches 3 years, 9 months ago
Maintainers: Alistair Francis <alistair@alistair23.me>, "Edgar E. Iglesias" <edgar.iglesias@gmail.com>, Peter Maydell <peter.maydell@linaro.org>
There is a newer version of this series
[PATCH v1 2/4] xlnx_dp: Introduce a vblank signal
Posted by frederic.konrad@xilinx.com 3 years, 9 months ago 
From: Sai Pavan Boddu <sai.pavan.boddu@xilinx.com>

Add a periodic timer which raises vblank at a frequency of 30Hz.

Signed-off-by: Sai Pavan Boddu <saipava@xilinx.com>
Signed-off-by: Edgar E. Iglesias <edgar.iglesias@xilinx.com>
Changes by fkonrad:
  - Switched to transaction-based ptimer API.
  - Added the DP_INT_VBLNK_START macro.
Signed-off-by: Frederic Konrad <fkonrad@amd.com>
---
 hw/display/xlnx_dp.c         | 24 +++++++++++++++++++++---
 include/hw/display/xlnx_dp.h |  3 +++
 2 files changed, 24 insertions(+), 3 deletions(-)

diff --git a/hw/display/xlnx_dp.c b/hw/display/xlnx_dp.c
index 0378570459..984b0a6bb9 100644
--- a/hw/display/xlnx_dp.c
+++ b/hw/display/xlnx_dp.c
@@ -114,6 +114,7 @@
 #define DP_TX_N_AUD                         (0x032C >> 2)
 #define DP_TX_AUDIO_EXT_DATA(n)             ((0x0330 + 4 * n) >> 2)
 #define DP_INT_STATUS                       (0x03A0 >> 2)
+#define DP_INT_VBLNK_START                  (1 << 13)
 #define DP_INT_MASK                         (0x03A4 >> 2)
 #define DP_INT_EN                           (0x03A8 >> 2)
 #define DP_INT_DS                           (0x03AC >> 2)
@@ -773,6 +774,14 @@ static void xlnx_dp_write(void *opaque, hwaddr offset, uint64_t value,
         break;
     case DP_TRANSMITTER_ENABLE:
         s->core_registers[offset] = value & 0x01;
+        ptimer_transaction_begin(s->vblank);
+        if (value & 0x1) {
+            ptimer_set_limit(s->vblank, 1, 1);
+            ptimer_run(s->vblank, 0);
+        } else {
+            ptimer_stop(s->vblank);
+        }
+        ptimer_transaction_commit(s->vblank);
         break;
     case DP_FORCE_SCRAMBLER_RESET:
         /*
@@ -1177,9 +1186,6 @@ static void xlnx_dp_update_display(void *opaque)
         return;
     }
 
-    s->core_registers[DP_INT_STATUS] |= (1 << 13);
-    xlnx_dp_update_irq(s);
-
     xlnx_dpdma_trigger_vsync_irq(s->dpdma);
 
     /*
@@ -1275,6 +1281,14 @@ static void xlnx_dp_finalize(Object *obj)
     fifo8_destroy(&s->rx_fifo);
 }
 
+static void vblank_hit(void *opaque)
+{
+    XlnxDPState *s = XLNX_DP(opaque);
+
+    s->core_registers[DP_INT_STATUS] |= DP_INT_VBLNK_START;
+    xlnx_dp_update_irq(s);
+}
+
 static void xlnx_dp_realize(DeviceState *dev, Error **errp)
 {
     XlnxDPState *s = XLNX_DP(dev);
@@ -1309,6 +1323,10 @@ static void xlnx_dp_realize(DeviceState *dev, Error **errp)
                                            &as);
     AUD_set_volume_out(s->amixer_output_stream, 0, 255, 255);
     xlnx_dp_audio_activate(s);
+    s->vblank = ptimer_init(vblank_hit, s, PTIMER_POLICY_DEFAULT);
+    ptimer_transaction_begin(s->vblank);
+    ptimer_set_freq(s->vblank, 30);
+    ptimer_transaction_commit(s->vblank);
 }
 
 static void xlnx_dp_reset(DeviceState *dev)
diff --git a/include/hw/display/xlnx_dp.h b/include/hw/display/xlnx_dp.h
index 1ef5a89ee7..e86a87f235 100644
--- a/include/hw/display/xlnx_dp.h
+++ b/include/hw/display/xlnx_dp.h
@@ -35,6 +35,7 @@
 #include "hw/dma/xlnx_dpdma.h"
 #include "audio/audio.h"
 #include "qom/object.h"
+#include "hw/ptimer.h"
 
 #define AUD_CHBUF_MAX_DEPTH                 (32 * KiB)
 #define MAX_QEMU_BUFFER_SIZE                (4 * KiB)
@@ -107,6 +108,8 @@ struct XlnxDPState {
      */
     DPCDState *dpcd;
     I2CDDCState *edid;
+
+    ptimer_state *vblank;
 };
 
 #define TYPE_XLNX_DP "xlnx.v-dp"
-- 
2.25.1
Re: [PATCH v1 2/4] xlnx_dp: Introduce a vblank signal
Posted by Peter Maydell 3 years, 9 months ago 
On Tue, 3 May 2022 at 16:27, <frederic.konrad@xilinx.com> wrote:
>
> From: Sai Pavan Boddu <sai.pavan.boddu@xilinx.com>
>
> Add a periodic timer which raises vblank at a frequency of 30Hz.
>
> Signed-off-by: Sai Pavan Boddu <saipava@xilinx.com>
> Signed-off-by: Edgar E. Iglesias <edgar.iglesias@xilinx.com>
> Changes by fkonrad:
>   - Switched to transaction-based ptimer API.
>   - Added the DP_INT_VBLNK_START macro.
> Signed-off-by: Frederic Konrad <fkonrad@amd.com>
> ---


> @@ -1309,6 +1323,10 @@ static void xlnx_dp_realize(DeviceState *dev, Error **errp)
>                                             &as);
>      AUD_set_volume_out(s->amixer_output_stream, 0, 255, 255);
>      xlnx_dp_audio_activate(s);
> +    s->vblank = ptimer_init(vblank_hit, s, PTIMER_POLICY_DEFAULT);
> +    ptimer_transaction_begin(s->vblank);
> +    ptimer_set_freq(s->vblank, 30);
> +    ptimer_transaction_commit(s->vblank);

The ptimer documentation (in include/hw/ptimer.h) says
 * The default ptimer policy retains backward compatibility with the legacy
 * timers. Custom policies are adjusting the default one. Consider providing
 * a correct policy for your timer.

and goes on to describe various weird behaviours of the default
policy. You almost certainly don't want to use PTIMER_POLICY_DEFAULT
for a new timer -- instead figure out the behaviour you actually
want and specify the appropriate flags.

thanks
-- PMM
RE: [PATCH v1 2/4] xlnx_dp: Introduce a vblank signal
Posted by Frederic Konrad 3 years, 9 months ago 

> -----Original Message-----
> From: Peter Maydell <peter.maydell@linaro.org>
> Sent: 16 May 2022 10:57
> To: Frederic Konrad <fkonrad@xilinx.com>
> Cc: qemu-devel@nongnu.org; alistair@alistair23.me;
> edgar.iglesias@gmail.com; qemu-arm@nongnu.org; Sai Pavan Boddu
> <saipava@xilinx.com>; Edgar Iglesias <edgari@xilinx.com>;
> fkonrad@amd.com; Sai Pavan Boddu <saipava@xilinx.com>; Edgar Iglesias
> <edgari@xilinx.com>
> Subject: Re: [PATCH v1 2/4] xlnx_dp: Introduce a vblank signal
> 
> On Tue, 3 May 2022 at 16:27, <frederic.konrad@xilinx.com> wrote:
> >
> > From: Sai Pavan Boddu <sai.pavan.boddu@xilinx.com>
> >
> > Add a periodic timer which raises vblank at a frequency of 30Hz.
> >
> > Signed-off-by: Sai Pavan Boddu <saipava@xilinx.com>
> > Signed-off-by: Edgar E. Iglesias <edgar.iglesias@xilinx.com>
> > Changes by fkonrad:
> >   - Switched to transaction-based ptimer API.
> >   - Added the DP_INT_VBLNK_START macro.
> > Signed-off-by: Frederic Konrad <fkonrad@amd.com>
> > ---
> 
> 
> > @@ -1309,6 +1323,10 @@ static void xlnx_dp_realize(DeviceState *dev,
> Error **errp)
> >                                             &as);
> >      AUD_set_volume_out(s->amixer_output_stream, 0, 255, 255);
> >      xlnx_dp_audio_activate(s);
> > +    s->vblank = ptimer_init(vblank_hit, s, PTIMER_POLICY_DEFAULT);
> > +    ptimer_transaction_begin(s->vblank);
> > +    ptimer_set_freq(s->vblank, 30);
> > +    ptimer_transaction_commit(s->vblank);
> 
> The ptimer documentation (in include/hw/ptimer.h) says
>  * The default ptimer policy retains backward compatibility with the legacy
>  * timers. Custom policies are adjusting the default one. Consider providing
>  * a correct policy for your timer.
> 
> and goes on to describe various weird behaviours of the default
> policy. You almost certainly don't want to use PTIMER_POLICY_DEFAULT
> for a new timer -- instead figure out the behaviour you actually
> want and specify the appropriate flags.

Hi Peter,

Thanks for your feedback.

Yes, I think, I can just use CONTINUOUS_TRIGGER and NO_IMMEDIATE_TRIGGER
instead of forcing the decrementer / reload value to 1.  Would that be cleaner?

Thanks,
Fred

> 
> thanks
> -- PMM
Re: [PATCH v1 2/4] xlnx_dp: Introduce a vblank signal
Posted by Peter Maydell 3 years, 9 months ago 
On Mon, 16 May 2022 at 11:36, Frederic Konrad <fkonrad@xilinx.com> wrote:
> > From: Peter Maydell <peter.maydell@linaro.org>
> >
> > On Tue, 3 May 2022 at 16:27, <frederic.konrad@xilinx.com> wrote:
> > The ptimer documentation (in include/hw/ptimer.h) says
> >  * The default ptimer policy retains backward compatibility with the legacy
> >  * timers. Custom policies are adjusting the default one. Consider providing
> >  * a correct policy for your timer.
> >
> > and goes on to describe various weird behaviours of the default
> > policy. You almost certainly don't want to use PTIMER_POLICY_DEFAULT
> > for a new timer -- instead figure out the behaviour you actually
> > want and specify the appropriate flags.
>
> Hi Peter,
>
> Thanks for your feedback.
>
> Yes, I think, I can just use CONTINUOUS_TRIGGER and NO_IMMEDIATE_TRIGGER
> instead of forcing the decrementer / reload value to 1.  Would that be cleaner?

I don't know exactly what behaviour you want, but you should probably
also consider PTIMER_POLICY_WRAP_AFTER_ONE_PERIOD.

-- PMM
Re: [PATCH v1 2/4] xlnx_dp: Introduce a vblank signal
Posted by Edgar E. Iglesias 3 years, 9 months ago 
On Tue, May 03, 2022 at 04:25:43PM +0100, frederic.konrad@xilinx.com wrote:
> From: Sai Pavan Boddu <sai.pavan.boddu@xilinx.com>
> 
> Add a periodic timer which raises vblank at a frequency of 30Hz.
>

Reviewed-by: Edgar E. Iglesias <edgar.iglesias@amd.com>

 
> Signed-off-by: Sai Pavan Boddu <saipava@xilinx.com>
> Signed-off-by: Edgar E. Iglesias <edgar.iglesias@xilinx.com>
> Changes by fkonrad:
>   - Switched to transaction-based ptimer API.
>   - Added the DP_INT_VBLNK_START macro.
> Signed-off-by: Frederic Konrad <fkonrad@amd.com>
> ---
>  hw/display/xlnx_dp.c         | 24 +++++++++++++++++++++---
>  include/hw/display/xlnx_dp.h |  3 +++
>  2 files changed, 24 insertions(+), 3 deletions(-)
> 
> diff --git a/hw/display/xlnx_dp.c b/hw/display/xlnx_dp.c
> index 0378570459..984b0a6bb9 100644
> --- a/hw/display/xlnx_dp.c
> +++ b/hw/display/xlnx_dp.c
> @@ -114,6 +114,7 @@
>  #define DP_TX_N_AUD                         (0x032C >> 2)
>  #define DP_TX_AUDIO_EXT_DATA(n)             ((0x0330 + 4 * n) >> 2)
>  #define DP_INT_STATUS                       (0x03A0 >> 2)
> +#define DP_INT_VBLNK_START                  (1 << 13)
>  #define DP_INT_MASK                         (0x03A4 >> 2)
>  #define DP_INT_EN                           (0x03A8 >> 2)
>  #define DP_INT_DS                           (0x03AC >> 2)
> @@ -773,6 +774,14 @@ static void xlnx_dp_write(void *opaque, hwaddr offset, uint64_t value,
>          break;
>      case DP_TRANSMITTER_ENABLE:
>          s->core_registers[offset] = value & 0x01;
> +        ptimer_transaction_begin(s->vblank);
> +        if (value & 0x1) {
> +            ptimer_set_limit(s->vblank, 1, 1);
> +            ptimer_run(s->vblank, 0);
> +        } else {
> +            ptimer_stop(s->vblank);
> +        }
> +        ptimer_transaction_commit(s->vblank);
>          break;
>      case DP_FORCE_SCRAMBLER_RESET:
>          /*
> @@ -1177,9 +1186,6 @@ static void xlnx_dp_update_display(void *opaque)
>          return;
>      }
>  
> -    s->core_registers[DP_INT_STATUS] |= (1 << 13);
> -    xlnx_dp_update_irq(s);
> -
>      xlnx_dpdma_trigger_vsync_irq(s->dpdma);
>  
>      /*
> @@ -1275,6 +1281,14 @@ static void xlnx_dp_finalize(Object *obj)
>      fifo8_destroy(&s->rx_fifo);
>  }
>  
> +static void vblank_hit(void *opaque)
> +{
> +    XlnxDPState *s = XLNX_DP(opaque);
> +
> +    s->core_registers[DP_INT_STATUS] |= DP_INT_VBLNK_START;
> +    xlnx_dp_update_irq(s);
> +}
> +
>  static void xlnx_dp_realize(DeviceState *dev, Error **errp)
>  {
>      XlnxDPState *s = XLNX_DP(dev);
> @@ -1309,6 +1323,10 @@ static void xlnx_dp_realize(DeviceState *dev, Error **errp)
>                                             &as);
>      AUD_set_volume_out(s->amixer_output_stream, 0, 255, 255);
>      xlnx_dp_audio_activate(s);
> +    s->vblank = ptimer_init(vblank_hit, s, PTIMER_POLICY_DEFAULT);
> +    ptimer_transaction_begin(s->vblank);
> +    ptimer_set_freq(s->vblank, 30);
> +    ptimer_transaction_commit(s->vblank);
>  }
>  
>  static void xlnx_dp_reset(DeviceState *dev)
> diff --git a/include/hw/display/xlnx_dp.h b/include/hw/display/xlnx_dp.h
> index 1ef5a89ee7..e86a87f235 100644
> --- a/include/hw/display/xlnx_dp.h
> +++ b/include/hw/display/xlnx_dp.h
> @@ -35,6 +35,7 @@
>  #include "hw/dma/xlnx_dpdma.h"
>  #include "audio/audio.h"
>  #include "qom/object.h"
> +#include "hw/ptimer.h"
>  
>  #define AUD_CHBUF_MAX_DEPTH                 (32 * KiB)
>  #define MAX_QEMU_BUFFER_SIZE                (4 * KiB)
> @@ -107,6 +108,8 @@ struct XlnxDPState {
>       */
>      DPCDState *dpcd;
>      I2CDDCState *edid;
> +
> +    ptimer_state *vblank;
>  };
>  
>  #define TYPE_XLNX_DP "xlnx.v-dp"
> -- 
> 2.25.1
>

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