dmaengine: bcm2835: add slave_sg support to bcm2835-dma (388cc7a2) · Commits · 戴 / test

drivers/dma/bcm2835-dma.c

+108 −5

Original line number	Diff line number	Diff line
		@@ -260,6 +260,23 @@ static void bcm2835_dma_create_cb_set_length(
		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;
		@@ -428,12 +471,18 @@ static irqreturn_t bcm2835_dma_callback(int irq, void *data)
		d = c->desc;

		if (d) {
		/* TODO Only works for cyclic DMA */
		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);
		writel(BCM2835_DMA_ACTIVE,
		c->chan_base + BCM2835_DMA_CS);
		} else {
		vchan_cookie_complete(&c->desc->vd);
		bcm2835_dma_start_desc(c);
		}
		}

		spin_unlock_irqrestore(&c->vc.lock, flags);

		@@ -548,6 +597,58 @@ static void bcm2835_dma_issue_pending(struct dma_chan *chan)
		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 platform_device *pdev)
		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);

Admin message