dmaengine: bcm2835: add dma_memcopy support to bcm2835-dma

Also added check for an error condition in bcm2835_dma_create_cb_chain
that showed up during development of this patch.

Tested using dmatest for all enabled channels.

Signed-off-by: Martin Sperl <kernel@martin.sperl.org>
Reviewed-by: Eric Anholt <eric@anholt.net>
Signed-off-by: Eric Anholt <eric@anholt.net>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>

1 files changed, 35 insertions, 1 deletions

diff --git a/drivers/dma/bcm2835-dma.c b/drivers/dma/bcm2835-dma.c
index b46b12f66f38..cc771cd35dd0 100644
--- a/drivers/dma/bcm2835-dma.c
+++ b/drivers/dma/bcm2835-dma.c
@@ -310,6 +310,9 @@ static struct bcm2835_desc *bcm2835_dma_create_cb_chain(
         struct bcm2835_cb_entry *cb_entry;
         struct bcm2835_dma_cb *control_block;
 
+        if (!frames)
+                return NULL;
+
         /* allocate and setup the descriptor. */
         d = kzalloc(sizeof(*d) + frames * sizeof(struct bcm2835_cb_entry),
                     gfp);
@@ -597,6 +600,34 @@ static void bcm2835_dma_issue_pending(struct dma_chan *chan)
         spin_unlock_irqrestore(&c->vc.lock, flags);
 }
 
+struct dma_async_tx_descriptor *bcm2835_dma_prep_dma_memcpy(
+        struct dma_chan *chan, dma_addr_t dst, dma_addr_t src,
+        size_t len, unsigned long flags)
+{
+        struct bcm2835_chan *c = to_bcm2835_dma_chan(chan);
+        struct bcm2835_desc *d;
+        u32 info = BCM2835_DMA_D_INC | BCM2835_DMA_S_INC;
+        u32 extra = BCM2835_DMA_INT_EN | BCM2835_DMA_WAIT_RESP;
+        size_t max_len = bcm2835_dma_max_frame_length(c);
+        size_t frames;
+
+        /* if src, dst or len is not given return with an error */
+        if (!src || !dst || !len)
+                return NULL;
+
+        /* calculate number of frames */
+        frames = bcm2835_dma_frames_for_length(len, max_len);
+
+        /* allocate the CB chain - this also fills in the pointers */
+        d = bcm2835_dma_create_cb_chain(chan, DMA_MEM_TO_MEM, false,
+                                        info, extra, frames,
+                                        src, dst, len, 0, GFP_KERNEL);
+        if (!d)
+                return NULL;
+
+        return vchan_tx_prep(&c->vc, &d->vd, flags);
+}
+
 static struct dma_async_tx_descriptor *bcm2835_dma_prep_slave_sg(
         struct dma_chan *chan,
         struct scatterlist *sgl, unsigned int sg_len,
@@ -880,17 +911,20 @@ static int bcm2835_dma_probe(struct platform_device *pdev)
         dma_cap_set(DMA_PRIVATE, od->ddev.cap_mask);
         dma_cap_set(DMA_CYCLIC, od->ddev.cap_mask);
         dma_cap_set(DMA_SLAVE, od->ddev.cap_mask);
+        dma_cap_set(DMA_MEMCPY, od->ddev.cap_mask);
         od->ddev.device_alloc_chan_resources = bcm2835_dma_alloc_chan_resources;
         od->ddev.device_free_chan_resources = bcm2835_dma_free_chan_resources;
         od->ddev.device_tx_status = bcm2835_dma_tx_status;
         od->ddev.device_issue_pending = bcm2835_dma_issue_pending;
         od->ddev.device_prep_dma_cyclic = bcm2835_dma_prep_dma_cyclic;
         od->ddev.device_prep_slave_sg = bcm2835_dma_prep_slave_sg;
+        od->ddev.device_prep_dma_memcpy = bcm2835_dma_prep_dma_memcpy;
         od->ddev.device_config = bcm2835_dma_slave_config;
         od->ddev.device_terminate_all = bcm2835_dma_terminate_all;
         od->ddev.src_addr_widths = BIT(DMA_SLAVE_BUSWIDTH_4_BYTES);
         od->ddev.dst_addr_widths = BIT(DMA_SLAVE_BUSWIDTH_4_BYTES);
-        od->ddev.directions = BIT(DMA_DEV_TO_MEM) | BIT(DMA_MEM_TO_DEV);
+        od->ddev.directions = BIT(DMA_DEV_TO_MEM) | BIT(DMA_MEM_TO_DEV) |
+                              BIT(DMA_MEM_TO_MEM);
         od->ddev.residue_granularity = DMA_RESIDUE_GRANULARITY_BURST;
         od->ddev.dev = &pdev->dev;
         INIT_LIST_HEAD(&od->ddev.channels);