diff options
| -rw-r--r-- | drivers/dma/bcm2835-dma.c | 29 |
1 files changed, 26 insertions, 3 deletions
diff --git a/drivers/dma/bcm2835-dma.c b/drivers/dma/bcm2835-dma.c index 4db0e232fab8..59c5ef36d970 100644 --- a/drivers/dma/bcm2835-dma.c +++ b/drivers/dma/bcm2835-dma.c @@ -81,6 +81,8 @@ struct bcm2835_chan { void __iomem *chan_base; int irq_number; + + bool is_lite_channel; }; struct bcm2835_desc { @@ -169,6 +171,16 @@ struct bcm2835_desc { #define BCM2835_DMA_CHAN(n) ((n) << 8) /* Base address */ #define BCM2835_DMA_CHANIO(base, n) ((base) + BCM2835_DMA_CHAN(n)) +/* the max dma length for different channels */ +#define MAX_DMA_LEN SZ_1G +#define MAX_LITE_DMA_LEN (SZ_64K - 4) + +static inline size_t bcm2835_dma_max_frame_length(struct bcm2835_chan *c) +{ + /* lite and normal channels have different max frame length */ + return c->is_lite_channel ? MAX_LITE_DMA_LEN : MAX_DMA_LEN; +} + /* how many frames of max_len size do we need to transfer len bytes */ static inline size_t bcm2835_dma_frames_for_length(size_t len, size_t max_len) @@ -217,8 +229,10 @@ static void bcm2835_dma_create_cb_set_length( size_t *total_len, u32 finalextrainfo) { - /* set the length */ - control_block->length = len; + size_t max_len = bcm2835_dma_max_frame_length(chan); + + /* set the length taking lite-channel limitations into account */ + control_block->length = min_t(u32, len, max_len); /* finished if we have no period_length */ if (!period_len) @@ -544,6 +558,7 @@ static struct dma_async_tx_descriptor *bcm2835_dma_prep_dma_cyclic( dma_addr_t src, dst; u32 info = BCM2835_DMA_WAIT_RESP; u32 extra = BCM2835_DMA_INT_EN; + size_t max_len = bcm2835_dma_max_frame_length(c); size_t frames; /* Grab configuration */ @@ -586,7 +601,10 @@ static struct dma_async_tx_descriptor *bcm2835_dma_prep_dma_cyclic( } /* calculate number of frames */ - frames = DIV_ROUND_UP(buf_len, period_len); + frames = /* number of periods */ + DIV_ROUND_UP(buf_len, period_len) * + /* number of frames per period */ + bcm2835_dma_frames_for_length(period_len, max_len); /* * allocate the CB chain @@ -685,6 +703,11 @@ static int bcm2835_dma_chan_init(struct bcm2835_dmadev *d, int chan_id, int irq) c->ch = chan_id; c->irq_number = irq; + /* check in DEBUG register if this is a LITE channel */ + if (readl(c->chan_base + BCM2835_DMA_DEBUG) & + BCM2835_DMA_DEBUG_LITE) + c->is_lite_channel = true; + return 0; } |