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.
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.

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

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