+++ /dev/null
-From dcfe16f80447e411dbe91144592f33f452fb6067 Mon Sep 17 00:00:00 2001
-From: Martin Sperl <kernel@martin.sperl.org>
-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 <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>
----
- 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);
projects / openwrt / staging / yousong.git / blobdiff