From: Peter Ujfalusi <peter.ujfalusi@ti.com>
To: Laurent Pinchart <laurent.pinchart@ideasonboard.com>,
<dmaengine@vger.kernel.org>
Cc: Michal Simek <michal.simek@xilinx.com>,
Hyun Kwon <hyun.kwon@xilinx.com>,
Tejas Upadhyay <tejasu@xilinx.com>,
Satish Kumar Nagireddy <SATISHNA@xilinx.com>,
Vinod Koul <vkoul@kernel.org>
Subject: Re: [PATCH v6 4/6] dmaengine: xilinx: dpdma: Add the Xilinx DisplayPort DMA engine driver
Date: Thu, 9 Jul 2020 16:21:38 +0300 [thread overview]
Message-ID: <64817596-1ba2-97d7-1dde-600eead16b05@ti.com> (raw)
In-Reply-To: <20200708201906.4546-5-laurent.pinchart@ideasonboard.com>
Hi Laurent,
On 08/07/2020 23.19, Laurent Pinchart wrote:
> From: Hyun Kwon <hyun.kwon@xilinx.com>
>
> The ZynqMP DisplayPort subsystem includes a DMA engine called DPDMA with
> 6 DMa channels (4 for display and 2 for audio). This driver exposes the
> DPDMA through the dmaengine API, to be used by audio (ALSA) and display
> (DRM) drivers for the DisplayPort subsystem.
>
> Signed-off-by: Hyun Kwon <hyun.kwon@xilinx.com>
> Signed-off-by: Tejas Upadhyay <tejasu@xilinx.com>
> Signed-off-by: Michal Simek <michal.simek@xilinx.com>
> Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
...
> +static void xilinx_dpdma_chan_queue_transfer(struct xilinx_dpdma_chan *chan)
> +{
> + struct xilinx_dpdma_device *xdev = chan->xdev;
> + struct xilinx_dpdma_sw_desc *sw_desc;
> + struct xilinx_dpdma_tx_desc *desc;
> + struct virt_dma_desc *vdesc;
> + u32 reg, channels;
> +
> + lockdep_assert_held(&chan->lock);
> +
> + if (chan->desc.pending)
> + return;
> +
> + if (!chan->running) {
> + xilinx_dpdma_chan_unpause(chan);
> + xilinx_dpdma_chan_enable(chan);
> + chan->first_frame = true;
> + chan->running = true;
> + }
> +
> + if (chan->video_group)
> + channels = xilinx_dpdma_chan_video_group_ready(chan);
> + else
> + channels = BIT(chan->id);
> +
> + if (!channels)
> + return;
> +
> + vdesc = vchan_next_desc(&chan->vchan);
> + if (!vdesc)
> + return;
> +
> + if (!chan->first_frame && !(vdesc->tx.flags & DMA_PREP_LOAD_EOT)) {
> + /*
> + * The client forgot to set the DMA_PREP_LOAD_EOT flag. The DMA
> + * engine API requires the channel to silently ignore the
> + * descriptor, leaving the client waiting forever for the new
> + * descriptor to be processed.
> + */
This hardly going to happen. But if it does, a gentle dev_dbg() might
save some time for the user on debugging?
> + return;
> + }
> +
> + desc = to_dpdma_tx_desc(vdesc);
> + chan->desc.pending = desc;
> + list_del(&desc->vdesc.node);
> +
> + /*
> + * Assign the cookie to descriptors in this transaction. Only 16 bit
> + * will be used, but it should be enough.
> + */
> + list_for_each_entry(sw_desc, &desc->descriptors, node)
> + sw_desc->hw.desc_id = desc->vdesc.tx.cookie;
> +
> + sw_desc = list_first_entry(&desc->descriptors,
> + struct xilinx_dpdma_sw_desc, node);
> + dpdma_write(chan->reg, XILINX_DPDMA_CH_DESC_START_ADDR,
> + lower_32_bits(sw_desc->dma_addr));
> + if (xdev->ext_addr)
> + dpdma_write(chan->reg, XILINX_DPDMA_CH_DESC_START_ADDRE,
> + FIELD_PREP(XILINX_DPDMA_CH_DESC_START_ADDRE_MASK,
> + upper_32_bits(sw_desc->dma_addr)));
> +
> + if (chan->first_frame)
> + reg = XILINX_DPDMA_GBL_TRIG_MASK(channels);
> + else
> + reg = XILINX_DPDMA_GBL_RETRIG_MASK(channels);
> +
> + chan->first_frame = false;
> +
> + dpdma_write(xdev->reg, XILINX_DPDMA_GBL, reg);
> +}
- Péter
Texas Instruments Finland Oy, Porkkalankatu 22, 00180 Helsinki.
Y-tunnus/Business ID: 0615521-4. Kotipaikka/Domicile: Helsinki
next prev parent reply other threads:[~2020-07-09 13:20 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-07-08 20:19 [PATCH v6 0/6] dma: Add Xilinx ZynqMP DPDMA driver Laurent Pinchart
2020-07-08 20:19 ` [PATCH v6 1/6] dt: bindings: dma: xilinx: dpdma: DT bindings for Xilinx DPDMA Laurent Pinchart
2020-07-08 20:19 ` [PATCH v6 2/6] dmaengine: virt-dma: Use lockdep to check locking requirements Laurent Pinchart
2020-07-09 13:07 ` Peter Ujfalusi
2020-07-11 19:53 ` Laurent Pinchart
2020-07-08 20:19 ` [PATCH v6 3/6] dmaengine: Add support for repeating transactions Laurent Pinchart
2020-07-09 13:25 ` Peter Ujfalusi
2020-07-08 20:19 ` [PATCH v6 4/6] dmaengine: xilinx: dpdma: Add the Xilinx DisplayPort DMA engine driver Laurent Pinchart
2020-07-09 13:21 ` Peter Ujfalusi [this message]
2020-07-11 22:16 ` Laurent Pinchart
2020-07-15 6:54 ` Vinod Koul
2020-07-15 10:59 ` Vinod Koul
2020-07-16 0:41 ` Laurent Pinchart
2020-07-16 5:21 ` Vinod Koul
2020-07-16 13:46 ` Laurent Pinchart
2020-07-17 5:59 ` Vinod Koul
2020-07-08 20:19 ` [PATCH v6 5/6] dmaengine: xilinx: dpdma: Add debugfs support Laurent Pinchart
2020-07-15 11:01 ` Vinod Koul
2020-07-16 0:42 ` Laurent Pinchart
2020-07-08 20:19 ` [PATCH v6 6/6] arm64: dts: zynqmp: Add DPDMA node Laurent Pinchart
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