From 9026efd53eae4b320941e581f141ddc87f2adc20 Mon Sep 17 00:00:00 2001 From: Martin Sperl Date: Wed, 16 Mar 2016 12:25:01 -0700 Subject: [PATCH] dmaengine: bcm2835: add slave_sg support to bcm2835-dma Add slave_sg support to bcm2835-dma using shared allocation code for bcm2835_desc and DMA-control blocks already used by dma_cyclic. Note that bcm2835_dma_callback had to get modified to support both modes of operation (cyclic and non-cyclic). Tested using: * Hifiberry I2S card (using cyclic DMA) * fb_st7735r SPI-framebuffer (using slave_sg DMA via spi-bcm2835) playing BigBuckBunny for audio and video. Signed-off-by: Martin Sperl Reviewed-by: Eric Anholt Signed-off-by: Eric Anholt Signed-off-by: Vinod Koul --- drivers/dma/bcm2835-dma.c | 113 ++++++++++++++++++++++++++++++++++++++++++++-- 1 file changed, 108 insertions(+), 5 deletions(-) --- a/drivers/dma/bcm2835-dma.c +++ b/drivers/dma/bcm2835-dma.c @@ -260,6 +260,23 @@ static void bcm2835_dma_create_cb_set_le control_block->info |= finalextrainfo; } +static inline size_t bcm2835_dma_count_frames_for_sg( + struct bcm2835_chan *c, + struct scatterlist *sgl, + unsigned int sg_len) +{ + size_t frames = 0; + struct scatterlist *sgent; + unsigned int i; + size_t plength = bcm2835_dma_max_frame_length(c); + + for_each_sg(sgl, sgent, sg_len, i) + frames += bcm2835_dma_frames_for_length( + sg_dma_len(sgent), plength); + + return frames; +} + /** * bcm2835_dma_create_cb_chain - create a control block and fills data in * @@ -361,6 +378,32 @@ error_cb: return NULL; } +static void bcm2835_dma_fill_cb_chain_with_sg( + struct dma_chan *chan, + enum dma_transfer_direction direction, + struct bcm2835_cb_entry *cb, + struct scatterlist *sgl, + unsigned int sg_len) +{ + struct bcm2835_chan *c = to_bcm2835_dma_chan(chan); + size_t max_len = bcm2835_dma_max_frame_length(c); + unsigned int i, len; + dma_addr_t addr; + struct scatterlist *sgent; + + for_each_sg(sgl, sgent, sg_len, i) { + for (addr = sg_dma_address(sgent), len = sg_dma_len(sgent); + len > 0; + addr += cb->cb->length, len -= cb->cb->length, cb++) { + if (direction == DMA_DEV_TO_MEM) + cb->cb->dst = addr; + else + cb->cb->src = addr; + cb->cb->length = min(len, max_len); + } + } +} + static int bcm2835_dma_abort(void __iomem *chan_base) { unsigned long cs; @@ -428,13 +471,19 @@ static irqreturn_t bcm2835_dma_callback( d = c->desc; if (d) { - /* TODO Only works for cyclic DMA */ - vchan_cyclic_callback(&d->vd); + if (d->cyclic) { + /* call the cyclic callback */ + vchan_cyclic_callback(&d->vd); + + /* Keep the DMA engine running */ + writel(BCM2835_DMA_ACTIVE, + c->chan_base + BCM2835_DMA_CS); + } else { + vchan_cookie_complete(&c->desc->vd); + bcm2835_dma_start_desc(c); + } } - /* Keep the DMA engine running */ - writel(BCM2835_DMA_ACTIVE, c->chan_base + BCM2835_DMA_CS); - spin_unlock_irqrestore(&c->vc.lock, flags); return IRQ_HANDLED; @@ -548,6 +597,58 @@ static void bcm2835_dma_issue_pending(st spin_unlock_irqrestore(&c->vc.lock, flags); } +static struct dma_async_tx_descriptor *bcm2835_dma_prep_slave_sg( + struct dma_chan *chan, + struct scatterlist *sgl, unsigned int sg_len, + enum dma_transfer_direction direction, + unsigned long flags, void *context) +{ + struct bcm2835_chan *c = to_bcm2835_dma_chan(chan); + struct bcm2835_desc *d; + dma_addr_t src = 0, dst = 0; + u32 info = BCM2835_DMA_WAIT_RESP; + u32 extra = BCM2835_DMA_INT_EN; + size_t frames; + + if (!is_slave_direction(direction)) { + dev_err(chan->device->dev, + "%s: bad direction?\n", __func__); + return NULL; + } + + if (c->dreq != 0) + info |= BCM2835_DMA_PER_MAP(c->dreq); + + if (direction == DMA_DEV_TO_MEM) { + if (c->cfg.src_addr_width != DMA_SLAVE_BUSWIDTH_4_BYTES) + return NULL; + src = c->cfg.src_addr; + info |= BCM2835_DMA_S_DREQ | BCM2835_DMA_D_INC; + } else { + if (c->cfg.dst_addr_width != DMA_SLAVE_BUSWIDTH_4_BYTES) + return NULL; + dst = c->cfg.dst_addr; + info |= BCM2835_DMA_D_DREQ | BCM2835_DMA_S_INC; + } + + /* count frames in sg list */ + frames = bcm2835_dma_count_frames_for_sg(c, sgl, sg_len); + + /* allocate the CB chain */ + d = bcm2835_dma_create_cb_chain(chan, direction, false, + info, extra, + frames, src, dst, 0, 0, + GFP_KERNEL); + if (!d) + return NULL; + + /* fill in frames with scatterlist pointers */ + bcm2835_dma_fill_cb_chain_with_sg(chan, direction, d->cb_list, + sgl, sg_len); + + return vchan_tx_prep(&c->vc, &d->vd, flags); +} + static struct dma_async_tx_descriptor *bcm2835_dma_prep_dma_cyclic( struct dma_chan *chan, dma_addr_t buf_addr, size_t buf_len, size_t period_len, enum dma_transfer_direction direction, @@ -778,11 +879,13 @@ static int bcm2835_dma_probe(struct plat dma_cap_set(DMA_SLAVE, od->ddev.cap_mask); 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); 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_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);