On Sat, Jan 07, 2017 at 12:15:29PM +0530, Kedareswara rao Appana wrote:
> When VDMA is configured for more than one frame in the h/w
> for example h/w is configured for n number of frames and user
> Submits n number of frames and triggered the DMA using issue_pending API.

title case in middle if sentence, no commas, can you make it easier to read
please..

> In the current driver flow we are submitting one frame at a time
> but we should submit all the n number of frames at one time as the h/w
> Is configured for n number of frames.

s/Is/is

> 
> This patch fixes this issue.
> 
> Reviewed-by: Jose Abreu <joab...@synopsys.com>
> Signed-off-by: Kedareswara rao Appana <appa...@xilinx.com>
> ---
> Changes for v5:
> ---> Updated xlnx,fstore-config property to xlnx,fstore-enable
>      and updated description as suggested by Rob.
> Changes for v4:
> ---> Add Check for framestore configuration on Transmit case as well
>      as suggested by Jose Abreu.
> ---> Modified the dev_dbg checks to dev_warn checks as suggested
>      by Jose Abreu.
> Changes for v3:
> ---> Added Checks for frame store configuration. If frame store
>      Configuration is not present at the h/w level and user
>      Submits less frames added debug prints in the driver as relevant.
> Changes for v2:
> ---> Fixed race conditions in the driver as suggested by Jose Abreu
> ---> Fixed unnecessray if else checks in the vdma_start_transfer
>      as suggested by Laurent Pinchart.
> 
>  .../devicetree/bindings/dma/xilinx/xilinx_dma.txt  |  2 +
>  drivers/dma/xilinx/xilinx_dma.c                    | 78 
> +++++++++++++++-------
>  2 files changed, 57 insertions(+), 23 deletions(-)
> 
> diff --git a/Documentation/devicetree/bindings/dma/xilinx/xilinx_dma.txt 
> b/Documentation/devicetree/bindings/dma/xilinx/xilinx_dma.txt
> index a2b8bfa..e951c09 100644
> --- a/Documentation/devicetree/bindings/dma/xilinx/xilinx_dma.txt
> +++ b/Documentation/devicetree/bindings/dma/xilinx/xilinx_dma.txt
> @@ -66,6 +66,8 @@ Optional child node properties:
>  Optional child node properties for VDMA:
>  - xlnx,genlock-mode: Tells Genlock synchronization is
>       enabled/disabled in hardware.
> +- xlnx,fstore-enable: boolean; if defined, it indicates that controller
> +     supports frame store configuration.
>  Optional child node properties for AXI DMA:
>  -dma-channels: Number of dma channels in child node.
>  
> diff --git a/drivers/dma/xilinx/xilinx_dma.c b/drivers/dma/xilinx/xilinx_dma.c
> index be7eb41..0e9c02e 100644
> --- a/drivers/dma/xilinx/xilinx_dma.c
> +++ b/drivers/dma/xilinx/xilinx_dma.c
> @@ -322,6 +322,7 @@ struct xilinx_dma_tx_descriptor {
>   * @genlock: Support genlock mode
>   * @err: Channel has errors
>   * @idle: Check for channel idle
> + * @has_fstoreen: Check for frame store configuration
>   * @tasklet: Cleanup work after irq
>   * @config: Device configuration info
>   * @flush_on_fsync: Flush on Frame sync
> @@ -353,6 +354,7 @@ struct xilinx_dma_chan {
>       bool genlock;
>       bool err;
>       bool idle;
> +     bool has_fstoreen;
>       struct tasklet_struct tasklet;
>       struct xilinx_vdma_config config;
>       bool flush_on_fsync;
> @@ -990,6 +992,27 @@ static void xilinx_vdma_start_transfer(struct 
> xilinx_dma_chan *chan)
>       if (list_empty(&chan->pending_list))
>               return;
>  
> +     /*
> +      * Note: When VDMA is built with default h/w configuration
> +      * User should submit frames upto H/W configured.
> +      * If users submits less than h/w configured
> +      * VDMA engine tries to write to a invalid location
> +      * Results undefined behaviour/memory corruption.
> +      *
> +      * If user would like to submit frames less than h/w capable
> +      * On S2MM side please enable debug info 13 at the h/w level
> +      * On MM2S side please enable debug info 6 at the h/w level
> +      * It will allows the frame buffers numbers to be modified at runtime.
> +      */
> +     if (!chan->has_fstoreen &&
> +          chan->desc_pendingcount < chan->num_frms) {
> +             dev_warn(chan->dev, "Frame Store Configuration is not enabled 
> at the\n");
> +             dev_warn(chan->dev, "H/w level enable Debug info 13 or 6 at the 
> h/w level\n");
> +             dev_warn(chan->dev, "OR Submit the frames upto h/w 
> Capable\n\r");
> +
> +             return;
> +     }
> +
>       desc = list_first_entry(&chan->pending_list,
>                               struct xilinx_dma_tx_descriptor, node);
>       tail_desc = list_last_entry(&chan->pending_list,
> @@ -1052,25 +1075,38 @@ static void xilinx_vdma_start_transfer(struct 
> xilinx_dma_chan *chan)
>       if (chan->has_sg) {
>               dma_ctrl_write(chan, XILINX_DMA_REG_TAILDESC,
>                               tail_segment->phys);
> +             list_splice_tail_init(&chan->pending_list, &chan->active_list);
> +             chan->desc_pendingcount = 0;
>       } else {
>               struct xilinx_vdma_tx_segment *segment, *last = NULL;
> -             int i = 0;
> +             int i = 0, j = 0;
>  
>               if (chan->desc_submitcount < chan->num_frms)
>                       i = chan->desc_submitcount;
>  
> -             list_for_each_entry(segment, &desc->segments, node) {
> -                     if (chan->ext_addr)
> -                             vdma_desc_write_64(chan,
> -                                     XILINX_VDMA_REG_START_ADDRESS_64(i++),
> -                                     segment->hw.buf_addr,
> -                                     segment->hw.buf_addr_msb);
> -                     else
> -                             vdma_desc_write(chan,
> -                                     XILINX_VDMA_REG_START_ADDRESS(i++),
> -                                     segment->hw.buf_addr);
> -
> -                     last = segment;
> +             for (j = 0; j < chan->num_frms; ) {
> +                     list_for_each_entry(segment, &desc->segments, node) {
> +                             if (chan->ext_addr)
> +                                     vdma_desc_write_64(chan,
> +                                       XILINX_VDMA_REG_START_ADDRESS_64(i++),
> +                                       segment->hw.buf_addr,
> +                                       segment->hw.buf_addr_msb);
> +                             else
> +                                     vdma_desc_write(chan,
> +                                         XILINX_VDMA_REG_START_ADDRESS(i++),
> +                                         segment->hw.buf_addr);
> +
> +                             last = segment;
> +                     }
> +                     list_del(&desc->node);
> +                     list_add_tail(&desc->node, &chan->active_list);
> +                     j++;
> +                     if (list_empty(&chan->pending_list) ||
> +                         (i == chan->num_frms))
> +                             break;
> +                     desc = list_first_entry(&chan->pending_list,
> +                                             struct xilinx_dma_tx_descriptor,
> +                                             node);
>               }
>  
>               if (!last)
> @@ -1081,20 +1117,14 @@ static void xilinx_vdma_start_transfer(struct 
> xilinx_dma_chan *chan)
>               vdma_desc_write(chan, XILINX_DMA_REG_FRMDLY_STRIDE,
>                               last->hw.stride);
>               vdma_desc_write(chan, XILINX_DMA_REG_VSIZE, last->hw.vsize);
> -     }
>  
> -     chan->idle = false;
> -     if (!chan->has_sg) {
> -             list_del(&desc->node);
> -             list_add_tail(&desc->node, &chan->active_list);
> -             chan->desc_submitcount++;
> -             chan->desc_pendingcount--;
> +             chan->desc_submitcount += j;
> +             chan->desc_pendingcount -= j;
>               if (chan->desc_submitcount == chan->num_frms)
>                       chan->desc_submitcount = 0;
> -     } else {
> -             list_splice_tail_init(&chan->pending_list, &chan->active_list);
> -             chan->desc_pendingcount = 0;
>       }
> +
> +     chan->idle = false;
>  }
>  
>  /**
> @@ -1342,6 +1372,7 @@ static int xilinx_dma_reset(struct xilinx_dma_chan 
> *chan)
>  
>       chan->err = false;
>       chan->idle = true;
> +     chan->desc_submitcount = 0;
>  
>       return err;
>  }
> @@ -2315,6 +2346,7 @@ static int xilinx_dma_chan_probe(struct 
> xilinx_dma_device *xdev,
>       has_dre = of_property_read_bool(node, "xlnx,include-dre");
>  
>       chan->genlock = of_property_read_bool(node, "xlnx,genlock-mode");
> +     chan->has_fstoreen = of_property_read_bool(node, "xlnx,fstore-enable");
>  
>       err = of_property_read_u32(node, "xlnx,datawidth", &value);
>       if (err) {
> -- 
> 2.1.2
> 

-- 
~Vinod

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