linux-kernel - [PATCH 2/2] dmaengine: omap-dma: Support for slave devices with data port window

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Date:   Tue, 25 Oct 2016 13:50:19 +0300
From:   Peter Ujfalusi <peter.ujfalusi@...com>
To:     <vinod.koul@...el.com>, <dan.j.williams@...el.com>,
        Tony Lindgren <tony@...mide.com>,
        Russell King - ARM Linux <linux@...linux.org.uk>
CC:     <dmaengine@...r.kernel.org>, <linux-kernel@...r.kernel.org>,
        <linux-omap@...r.kernel.org>, <arnd@...db.de>
Subject: [PATCH 2/2] dmaengine: omap-dma: Support for slave devices with data port window

Based on the src/dst_port_window_size - if it is set - configure the DMA
channel to use double indexing in order to be able to loop within the
address window.

Signed-off-by: Peter Ujfalusi <peter.ujfalusi@...com>
---
 drivers/dma/omap-dma.c | 45 +++++++++++++++++++++++++++++++++++++++++++--
 1 file changed, 43 insertions(+), 2 deletions(-)

diff --git a/drivers/dma/omap-dma.c b/drivers/dma/omap-dma.c
index 025f499cb20d..29350f936154 100644
--- a/drivers/dma/omap-dma.c
+++ b/drivers/dma/omap-dma.c
@@ -166,6 +166,9 @@ enum {
 	CSDP_DST_BURST_16	= 1 << 14,
 	CSDP_DST_BURST_32	= 2 << 14,
 	CSDP_DST_BURST_64	= 3 << 14,
+	CSDP_WRITE_NON_POSTED	= (0 << 16),
+	CSDP_WRITE_POSTED	= (1 << 16),
+	CSDP_WRITE_LAST_NON_POSTED = (2 << 16),
 
 	CICR_TOUT_IE		= BIT(0),	/* OMAP1 only */
 	CICR_DROP_IE		= BIT(1),
@@ -883,15 +886,18 @@ static struct dma_async_tx_descriptor *omap_dma_prep_slave_sg(
 	unsigned i, es, en, frame_bytes;
 	bool ll_failed = false;
 	u32 burst;
+	int32_t port_window;
 
 	if (dir == DMA_DEV_TO_MEM) {
 		dev_addr = c->cfg.src_addr;
 		dev_width = c->cfg.src_addr_width;
 		burst = c->cfg.src_maxburst;
+		port_window = c->cfg.src_port_window_size;
 	} else if (dir == DMA_MEM_TO_DEV) {
 		dev_addr = c->cfg.dst_addr;
 		dev_width = c->cfg.dst_addr_width;
 		burst = c->cfg.dst_maxburst;
+		port_window = c->cfg.dst_port_window_size;
 	} else {
 		dev_err(chan->device->dev, "%s: bad direction?\n", __func__);
 		return NULL;
@@ -923,11 +929,39 @@ static struct dma_async_tx_descriptor *omap_dma_prep_slave_sg(
 
 	d->ccr = c->ccr | CCR_SYNC_FRAME;
 	if (dir == DMA_DEV_TO_MEM) {
-		d->ccr |= CCR_DST_AMODE_POSTINC | CCR_SRC_AMODE_CONSTANT;
 		d->csdp = CSDP_DST_BURST_64 | CSDP_DST_PACKED;
+
+		d->ccr |= CCR_DST_AMODE_POSTINC;
+		if (port_window) {
+			d->ccr |= CCR_SRC_AMODE_DBLIDX;
+			d->ei = 1;
+			d->fi = (-1) * (port_window - 1);
+
+			if (port_window / 64)
+				d->csdp = CSDP_SRC_BURST_64 | CSDP_SRC_PACKED;
+			else if (port_window / 32)
+				d->csdp = CSDP_SRC_BURST_32 | CSDP_SRC_PACKED;
+			else if (port_window / 16)
+				d->csdp = CSDP_SRC_BURST_16 | CSDP_SRC_PACKED;
+		} else {
+			d->ccr |= CCR_SRC_AMODE_CONSTANT;
+		}
 	} else {
-		d->ccr |= CCR_DST_AMODE_CONSTANT | CCR_SRC_AMODE_POSTINC;
 		d->csdp = CSDP_SRC_BURST_64 | CSDP_SRC_PACKED;
+
+		d->ccr |= CCR_SRC_AMODE_POSTINC;
+		if (port_window) {
+			d->ccr |= CCR_DST_AMODE_DBLIDX;
+
+			if (port_window / 64)
+				d->csdp = CSDP_DST_BURST_64 | CSDP_DST_PACKED;
+			else if (port_window / 32)
+				d->csdp = CSDP_DST_BURST_32 | CSDP_DST_PACKED;
+			else if (port_window / 16)
+				d->csdp = CSDP_DST_BURST_16 | CSDP_DST_PACKED;
+		} else {
+			d->ccr |= CCR_DST_AMODE_CONSTANT;
+		}
 	}
 
 	d->cicr = CICR_DROP_IE | CICR_BLOCK_IE;
@@ -945,6 +979,9 @@ static struct dma_async_tx_descriptor *omap_dma_prep_slave_sg(
 			d->ccr |= CCR_TRIGGER_SRC;
 
 		d->cicr |= CICR_MISALIGNED_ERR_IE | CICR_TRANS_ERR_IE;
+
+		if (port_window)
+			d->csdp |= CSDP_WRITE_LAST_NON_POSTED;
 	}
 	if (od->plat->errata & DMA_ERRATA_PARALLEL_CHANNELS)
 		d->clnk_ctrl = c->dma_ch;
@@ -970,6 +1007,10 @@ static struct dma_async_tx_descriptor *omap_dma_prep_slave_sg(
 		osg->addr = sg_dma_address(sgent);
 		osg->en = en;
 		osg->fn = sg_dma_len(sgent) / frame_bytes;
+		if (port_window && dir == DMA_MEM_TO_DEV) {
+			osg->ei = 1;
+			osg->fi = (-1) * (port_window - 1);
+		}
 
 		if (d->using_ll) {
 			osg->t2_desc = dma_pool_alloc(od->desc_pool, GFP_ATOMIC,
-- 
2.10.1