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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 <kernel@martin.sperl.org> Reviewed-by: Eric Anholt <eric@anholt.net> Signed-off-by: Eric Anholt <eric@anholt.net> Signed-off-by: Vinod Koul <vinod.koul@intel.com>
This commit is contained in:
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4087412258
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388cc7a281
@ -260,6 +260,23 @@ static void bcm2835_dma_create_cb_set_length(
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control_block->info |= finalextrainfo;
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}
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static inline size_t bcm2835_dma_count_frames_for_sg(
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struct bcm2835_chan *c,
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struct scatterlist *sgl,
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unsigned int sg_len)
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{
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size_t frames = 0;
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struct scatterlist *sgent;
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unsigned int i;
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size_t plength = bcm2835_dma_max_frame_length(c);
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for_each_sg(sgl, sgent, sg_len, i)
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frames += bcm2835_dma_frames_for_length(
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sg_dma_len(sgent), plength);
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return frames;
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}
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/**
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* bcm2835_dma_create_cb_chain - create a control block and fills data in
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*
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@ -361,6 +378,32 @@ error_cb:
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return NULL;
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}
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static void bcm2835_dma_fill_cb_chain_with_sg(
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struct dma_chan *chan,
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enum dma_transfer_direction direction,
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struct bcm2835_cb_entry *cb,
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struct scatterlist *sgl,
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unsigned int sg_len)
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{
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struct bcm2835_chan *c = to_bcm2835_dma_chan(chan);
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size_t max_len = bcm2835_dma_max_frame_length(c);
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unsigned int i, len;
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dma_addr_t addr;
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struct scatterlist *sgent;
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for_each_sg(sgl, sgent, sg_len, i) {
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for (addr = sg_dma_address(sgent), len = sg_dma_len(sgent);
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len > 0;
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addr += cb->cb->length, len -= cb->cb->length, cb++) {
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if (direction == DMA_DEV_TO_MEM)
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cb->cb->dst = addr;
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else
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cb->cb->src = addr;
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cb->cb->length = min(len, max_len);
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}
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}
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}
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static int bcm2835_dma_abort(void __iomem *chan_base)
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{
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unsigned long cs;
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@ -428,12 +471,18 @@ static irqreturn_t bcm2835_dma_callback(int irq, void *data)
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d = c->desc;
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if (d) {
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/* TODO Only works for cyclic DMA */
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vchan_cyclic_callback(&d->vd);
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}
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if (d->cyclic) {
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/* call the cyclic callback */
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vchan_cyclic_callback(&d->vd);
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/* Keep the DMA engine running */
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writel(BCM2835_DMA_ACTIVE, c->chan_base + BCM2835_DMA_CS);
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/* Keep the DMA engine running */
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writel(BCM2835_DMA_ACTIVE,
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c->chan_base + BCM2835_DMA_CS);
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} else {
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vchan_cookie_complete(&c->desc->vd);
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bcm2835_dma_start_desc(c);
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}
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}
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spin_unlock_irqrestore(&c->vc.lock, flags);
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@ -548,6 +597,58 @@ static void bcm2835_dma_issue_pending(struct dma_chan *chan)
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spin_unlock_irqrestore(&c->vc.lock, flags);
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}
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static struct dma_async_tx_descriptor *bcm2835_dma_prep_slave_sg(
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struct dma_chan *chan,
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struct scatterlist *sgl, unsigned int sg_len,
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enum dma_transfer_direction direction,
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unsigned long flags, void *context)
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{
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struct bcm2835_chan *c = to_bcm2835_dma_chan(chan);
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struct bcm2835_desc *d;
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dma_addr_t src = 0, dst = 0;
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u32 info = BCM2835_DMA_WAIT_RESP;
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u32 extra = BCM2835_DMA_INT_EN;
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size_t frames;
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if (!is_slave_direction(direction)) {
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dev_err(chan->device->dev,
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"%s: bad direction?\n", __func__);
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return NULL;
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}
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if (c->dreq != 0)
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info |= BCM2835_DMA_PER_MAP(c->dreq);
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if (direction == DMA_DEV_TO_MEM) {
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if (c->cfg.src_addr_width != DMA_SLAVE_BUSWIDTH_4_BYTES)
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return NULL;
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src = c->cfg.src_addr;
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info |= BCM2835_DMA_S_DREQ | BCM2835_DMA_D_INC;
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} else {
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if (c->cfg.dst_addr_width != DMA_SLAVE_BUSWIDTH_4_BYTES)
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return NULL;
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dst = c->cfg.dst_addr;
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info |= BCM2835_DMA_D_DREQ | BCM2835_DMA_S_INC;
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}
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/* count frames in sg list */
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frames = bcm2835_dma_count_frames_for_sg(c, sgl, sg_len);
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/* allocate the CB chain */
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d = bcm2835_dma_create_cb_chain(chan, direction, false,
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info, extra,
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frames, src, dst, 0, 0,
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GFP_KERNEL);
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if (!d)
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return NULL;
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/* fill in frames with scatterlist pointers */
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bcm2835_dma_fill_cb_chain_with_sg(chan, direction, d->cb_list,
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sgl, sg_len);
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return vchan_tx_prep(&c->vc, &d->vd, flags);
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}
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static struct dma_async_tx_descriptor *bcm2835_dma_prep_dma_cyclic(
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struct dma_chan *chan, dma_addr_t buf_addr, size_t buf_len,
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size_t period_len, enum dma_transfer_direction direction,
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@ -778,11 +879,13 @@ static int bcm2835_dma_probe(struct platform_device *pdev)
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dma_cap_set(DMA_SLAVE, od->ddev.cap_mask);
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dma_cap_set(DMA_PRIVATE, od->ddev.cap_mask);
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dma_cap_set(DMA_CYCLIC, od->ddev.cap_mask);
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dma_cap_set(DMA_SLAVE, od->ddev.cap_mask);
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od->ddev.device_alloc_chan_resources = bcm2835_dma_alloc_chan_resources;
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od->ddev.device_free_chan_resources = bcm2835_dma_free_chan_resources;
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od->ddev.device_tx_status = bcm2835_dma_tx_status;
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od->ddev.device_issue_pending = bcm2835_dma_issue_pending;
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od->ddev.device_prep_dma_cyclic = bcm2835_dma_prep_dma_cyclic;
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od->ddev.device_prep_slave_sg = bcm2835_dma_prep_slave_sg;
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od->ddev.device_config = bcm2835_dma_slave_config;
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od->ddev.device_terminate_all = bcm2835_dma_terminate_all;
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od->ddev.src_addr_widths = BIT(DMA_SLAVE_BUSWIDTH_4_BYTES);
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