dmaeninge: xilinx_dma: Fix bug in multiple frame stores scenario in vdma

VDMA engine default frame buffer configuration is cirular mode.
in this mode dmaengine continuously circles through h/w configured fstore
frame buffers.

When vdma h/w is configured for more than one frame.
for example h/w is configured for n number of frames, user
submits less than n number of frames and triggered the dmaengine
using issue_pending API.

since the h/w (or) driver default configuraiton is circular mode
h/w tries to write/read from an invalid frame buffer resulting
errors from the vdma dmaengine.

This patch fixes this issue by enabling the park mode as
default mode configuration for frame buffers in s/w,
so that driver can handle all cases for "k" frames where n%k==0
(n is a multiple of k) by simply replicating the frame pointers.

Signed-off-by: Kedareswara rao Appana <appanad@xilinx.com>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>

diff --git a/drivers/dma/xilinx/xilinx_dma.c b/drivers/dma/xilinx/xilinx_dma.c
index c2465632f3f0f4d18e4f54129ae4c5bbdc132b57..9063ca04e8d60bde201e097f8cfea0e833860571 100644 (file)
--- a/drivers/dma/xilinx/xilinx_dma.c
+++ b/drivers/dma/xilinx/xilinx_dma.c
@@ -99,7 +99,9 @@
 #define XILINX_DMA_REG_FRMPTR_STS              0x0024
 #define XILINX_DMA_REG_PARK_PTR                0x0028
 #define XILINX_DMA_PARK_PTR_WR_REF_SHIFT       8
+#define XILINX_DMA_PARK_PTR_WR_REF_MASK                GENMASK(12, 8)
 #define XILINX_DMA_PARK_PTR_RD_REF_SHIFT       0
+#define XILINX_DMA_PARK_PTR_RD_REF_MASK                GENMASK(4, 0)
 #define XILINX_DMA_REG_VDMA_VERSION            0x002c
 
 /* Register Direct Mode Registers */
@@ -998,7 +1000,7 @@ static void xilinx_vdma_start_transfer(struct xilinx_dma_chan *chan)
 {
        struct xilinx_vdma_config *config = &chan->config;
        struct xilinx_dma_tx_descriptor *desc, *tail_desc;
-       u32 reg;
+       u32 reg, j;
        struct xilinx_vdma_tx_segment *tail_segment;
 
        /* This function was invoked with lock held */
@@ -1035,10 +1037,6 @@ static void xilinx_vdma_start_transfer(struct xilinx_dma_chan *chan)
        else
                reg &= ~XILINX_DMA_DMACR_FRAMECNT_EN;
 
-       /* Configure channel to allow number frame buffers */
-       dma_ctrl_write(chan, XILINX_DMA_REG_FRMSTORE,
-                       chan->desc_pendingcount);
-
        /*
         * With SG, start with circular mode, so that BDs can be fetched.
         * In direct register mode, if not parking, enable circular mode
@@ -1051,17 +1049,16 @@ static void xilinx_vdma_start_transfer(struct xilinx_dma_chan *chan)
 
        dma_ctrl_write(chan, XILINX_DMA_REG_DMACR, reg);
 
-       if (config->park && (config->park_frm >= 0) &&
-                       (config->park_frm < chan->num_frms)) {
-               if (chan->direction == DMA_MEM_TO_DEV)
-                       dma_write(chan, XILINX_DMA_REG_PARK_PTR,
-                               config->park_frm <<
-                                       XILINX_DMA_PARK_PTR_RD_REF_SHIFT);
-               else
-                       dma_write(chan, XILINX_DMA_REG_PARK_PTR,
-                               config->park_frm <<
-                                       XILINX_DMA_PARK_PTR_WR_REF_SHIFT);
+       j = chan->desc_submitcount;
+       reg = dma_read(chan, XILINX_DMA_REG_PARK_PTR);
+       if (chan->direction == DMA_MEM_TO_DEV) {
+               reg &= ~XILINX_DMA_PARK_PTR_RD_REF_MASK;
+               reg |= j << XILINX_DMA_PARK_PTR_RD_REF_SHIFT;
+       } else {
+               reg &= ~XILINX_DMA_PARK_PTR_WR_REF_MASK;
+               reg |= j << XILINX_DMA_PARK_PTR_WR_REF_SHIFT;
        }
+       dma_write(chan, XILINX_DMA_REG_PARK_PTR, reg);
 
        /* Start the hardware */
        xilinx_dma_start(chan);
@@ -1073,6 +1070,8 @@ 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;
@@ -1102,18 +1101,13 @@ 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);
-       }
 
-       if (!chan->has_sg) {
-               list_del(&desc->node);
-               list_add_tail(&desc->node, &chan->active_list);
                chan->desc_submitcount++;
                chan->desc_pendingcount--;
+               list_del(&desc->node);
+               list_add_tail(&desc->node, &chan->active_list);
                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;
@@ -1364,6 +1358,7 @@ static int xilinx_dma_reset(struct xilinx_dma_chan *chan)
 
        chan->err = false;
        chan->idle = true;
+       chan->desc_submitcount = 0;
 
        return err;
 }
@@ -2363,6 +2358,7 @@ static int xilinx_dma_chan_probe(struct xilinx_dma_device *xdev,
                chan->ctrl_offset = XILINX_DMA_MM2S_CTRL_OFFSET;
                if (xdev->dma_config->dmatype == XDMA_TYPE_VDMA) {
                        chan->desc_offset = XILINX_VDMA_MM2S_DESC_OFFSET;
+                       chan->config.park = 1;
 
                        if (xdev->flush_on_fsync == XILINX_DMA_FLUSH_BOTH ||
                            xdev->flush_on_fsync == XILINX_DMA_FLUSH_MM2S)
@@ -2379,6 +2375,7 @@ static int xilinx_dma_chan_probe(struct xilinx_dma_device *xdev,
                chan->ctrl_offset = XILINX_DMA_S2MM_CTRL_OFFSET;
                if (xdev->dma_config->dmatype == XDMA_TYPE_VDMA) {
                        chan->desc_offset = XILINX_VDMA_S2MM_DESC_OFFSET;
+                       chan->config.park = 1;
 
                        if (xdev->flush_on_fsync == XILINX_DMA_FLUSH_BOTH ||
                            xdev->flush_on_fsync == XILINX_DMA_FLUSH_S2MM)