diff options
Diffstat (limited to 'drivers/dma')
| -rw-r--r-- | drivers/dma/sun4i-dma.c | 32 |
1 files changed, 27 insertions, 5 deletions
diff --git a/drivers/dma/sun4i-dma.c b/drivers/dma/sun4i-dma.c index 93f1645ae928..f291b1b4db32 100644 --- a/drivers/dma/sun4i-dma.c +++ b/drivers/dma/sun4i-dma.c @@ -7,6 +7,7 @@ #include <linux/bitmap.h> #include <linux/bitops.h> #include <linux/clk.h> +#include <linux/dma-mapping.h> #include <linux/dmaengine.h> #include <linux/dmapool.h> #include <linux/interrupt.h> @@ -122,6 +123,15 @@ SUN4I_DDMA_PARA_DST_WAIT_CYCLES(2) | \ SUN4I_DDMA_PARA_SRC_WAIT_CYCLES(2)) +/* + * Normal DMA supports individual transfers (segments) up to 128k. + * Dedicated DMA supports transfers up to 16M. We can only report + * one size limit, so we have to use the smaller value. + */ +#define SUN4I_NDMA_MAX_SEG_SIZE SZ_128K +#define SUN4I_DDMA_MAX_SEG_SIZE SZ_16M +#define SUN4I_DMA_MAX_SEG_SIZE SUN4I_NDMA_MAX_SEG_SIZE + struct sun4i_dma_pchan { /* Register base of channel */ void __iomem *base; @@ -155,7 +165,8 @@ struct sun4i_dma_contract { struct virt_dma_desc vd; struct list_head demands; struct list_head completed_demands; - int is_cyclic; + bool is_cyclic : 1; + bool use_half_int : 1; }; struct sun4i_dma_dev { @@ -372,7 +383,7 @@ static int __execute_vchan_pending(struct sun4i_dma_dev *priv, if (promise) { vchan->contract = contract; vchan->pchan = pchan; - set_pchan_interrupt(priv, pchan, contract->is_cyclic, 1); + set_pchan_interrupt(priv, pchan, contract->use_half_int, 1); configure_pchan(pchan, promise); } @@ -735,12 +746,21 @@ sun4i_dma_prep_dma_cyclic(struct dma_chan *chan, dma_addr_t buf, size_t len, * * Which requires half the engine programming for the same * functionality. + * + * This only works if two periods fit in a single promise. That will + * always be the case for dedicated DMA, where the hardware has a much + * larger maximum transfer size than advertised to clients. */ - nr_periods = DIV_ROUND_UP(len / period_len, 2); + if (vchan->is_dedicated || period_len <= SUN4I_NDMA_MAX_SEG_SIZE / 2) { + period_len *= 2; + contract->use_half_int = 1; + } + + nr_periods = DIV_ROUND_UP(len, period_len); for (i = 0; i < nr_periods; i++) { /* Calculate the offset in the buffer and the length needed */ - offset = i * period_len * 2; - plength = min((len - offset), (period_len * 2)); + offset = i * period_len; + plength = min((len - offset), period_len); if (dir == DMA_MEM_TO_DEV) src = buf + offset; else @@ -1149,6 +1169,8 @@ static int sun4i_dma_probe(struct platform_device *pdev) platform_set_drvdata(pdev, priv); spin_lock_init(&priv->lock); + dma_set_max_seg_size(&pdev->dev, SUN4I_DMA_MAX_SEG_SIZE); + dma_cap_zero(priv->slave.cap_mask); dma_cap_set(DMA_PRIVATE, priv->slave.cap_mask); dma_cap_set(DMA_MEMCPY, priv->slave.cap_mask); |