[PATCH 2/5] dmaengine: omap-dma: Implement protection for invalid max_burst

Peter Ujfalusi
2017-09-12T10:45:57Z

﻿Set the device's max_burst to 16777215 (EN is 24bit unsigned value) so
clients can take this into consideration when setting up the trasnfer.

During slave transfer preparation check if the requested maxburst is valid.

Signed-off-by: Peter Ujfalusi <peter.ujfalusi@ti.com>
---
drivers/dma/omap-dma.c | 5 +++++
1 file changed, 5 insertions(+)

diff --git a/drivers/dma/omap-dma.c b/drivers/dma/omap-dma.c
index 8c1665c8fe33..f6dd849159d8 100644
--- a/drivers/dma/omap-dma.c
+++ b/drivers/dma/omap-dma.c
@@ -1288,6 +1288,10 @@ static int omap_dma_slave_config(struct dma_chan *chan, struct dma_slave_config
cfg->dst_addr_width == DMA_SLAVE_BUSWIDTH_8_BYTES)
return -EINVAL;

+ if (cfg->src_maxburst > chan->device->max_burst ||
+ cfg->dst_maxburst > chan->device->max_burst)
+ return -EINVAL;
+
memcpy(&c->cfg, cfg, sizeof(c->cfg));

return 0;
@@ -1482,6 +1486,7 @@ static int omap_dma_probe(struct platform_device *pdev)
od->ddev.dst_addr_widths = OMAP_DMA_BUSWIDTHS;
od->ddev.directions = BIT(DMA_DEV_TO_MEM) | BIT(DMA_MEM_TO_DEV);
od->ddev.residue_granularity = DMA_RESIDUE_GRANULARITY_BURST;
+ od->ddev.max_burst = SZ_16M - 1; /* CCEN: 24bit unsigned */
od->ddev.dev = &pdev->dev;
INIT_LIST_HEAD(&od->ddev.channels);
spin_lock_init(&od->lock);
--
2.14.1