This patch extends the capabilities of the driver to handle DMA
transfers to and from devices of 1, 2, 4, 16 (for MPC512x), and 32 byte
widths.
Signed-off-by: Mario Six <mario.six@xxxxxxxx>
---
drivers/dma/mpc512x_dma.c | 112 +++++++++++++++++++++++++++++++---------------
1 file changed, 76 insertions(+), 36 deletions(-)
diff --git a/drivers/dma/mpc512x_dma.c b/drivers/dma/mpc512x_dma.c
index 3a9104a..1a161a8 100644
--- a/drivers/dma/mpc512x_dma.c
+++ b/drivers/dma/mpc512x_dma.c
@@ -3,6 +3,7 @@
* Copyright (C) Semihalf 2009
* Copyright (C) Ilya Yanok, Emcraft Systems 2010
* Copyright (C) Alexander Popov, Promcontroller 2014
+ * Copyright (C) Mario Six, Guntermann & Drunck GmbH, 2016
*
* Written by Piotr Ziecik <kosmo@xxxxxxxxxxxx>. Hardware description
* (defines, structures and comments) was taken from MPC5121 DMA driver
@@ -26,18 +27,19 @@
*/
/*
- * MPC512x and MPC8308 DMA driver. It supports
- * memory to memory data transfers (tested using dmatest module) and
- * data transfers between memory and peripheral I/O memory
- * by means of slave scatter/gather with these limitations:
- * - chunked transfers (described by s/g lists with more than one item)
- * are refused as long as proper support for scatter/gather is missing;
- * - transfers on MPC8308 always start from software as this SoC appears
- * not to have external request lines for peripheral flow control;
- * - only peripheral devices with 4-byte FIFO access register are supported;
- * - minimal memory <-> I/O memory transfer chunk is 4 bytes and consequently
- * source and destination addresses must be 4-byte aligned
- * and transfer size must be aligned on (4 * maxburst) boundary;
+ * MPC512x and MPC8308 DMA driver. It supports memory to memory data transfers
+ * (tested using dmatest module) and data transfers between memory and
+ * peripheral I/O memory by means of slave scatter/gather with these
+ * limitations:
+ * - chunked transfers (described by s/g lists with more than one item) are
+ * refused as long as proper support for scatter/gather is missing
+ * - transfers on MPC8308 always start from software as this SoC does not have
+ * external request lines for peripheral flow control
+ * - memory <-> I/O memory transfer chunks of sizes of 1, 2, 4, 16 (for
+ * MPC512x), and 32 bytes are supported, and, consequently, source
+ * addresses and destination addresses must be aligned accordingly;
+ * furthermore, for MPC512x SoCs, the transfer size must be aligned on
+ * (chunk size * maxburst)
*/
#include <linux/module.h>
@@ -213,8 +215,10 @@ struct mpc_dma_chan {
/* Settings for access to peripheral FIFO */
dma_addr_t src_per_paddr;
u32 src_tcd_nunits;
+ u8 swidth;
dma_addr_t dst_per_paddr;
u32 dst_tcd_nunits;
+ u8 dwidth;
/* Lock for this structure */
spinlock_t lock;
@@ -684,6 +688,15 @@ mpc_dma_prep_memcpy(struct dma_chan *chan, dma_addr_t dst, dma_addr_t src,
return &mdesc->desc;
}
+inline u8 buswidth_to_dmatsize(u8 buswidth)
+{
+ u8 res;
+
+ for (res = 0; buswidth > 1; buswidth /= 2)
+ res++;
+ return res;
+}
+
static struct dma_async_tx_descriptor *
mpc_dma_prep_slave_sg(struct dma_chan *chan, struct scatterlist *sgl,
unsigned int sg_len, enum dma_transfer_direction direction,
@@ -742,27 +755,32 @@ mpc_dma_prep_slave_sg(struct dma_chan *chan, struct scatterlist *sgl,
memset(tcd, 0, sizeof(struct mpc_dma_tcd));
- if (!IS_ALIGNED(sg_dma_address(sg), 4))
- goto err_prep;
-
if (direction == DMA_DEV_TO_MEM) {
tcd->saddr = per_paddr;
tcd->daddr = sg_dma_address(sg);
+
+ if (!IS_ALIGNED(sg_dma_address(sg), mchan->dwidth))
+ goto err_prep;
+
tcd->soff = 0;
- tcd->doff = 4;
+ tcd->doff = mchan->dwidth;
} else {
tcd->saddr = sg_dma_address(sg);
tcd->daddr = per_paddr;
- tcd->soff = 4;
+
+ if (!IS_ALIGNED(sg_dma_address(sg), mchan->swidth))
+ goto err_prep;
+
+ tcd->soff = mchan->swidth;
tcd->doff = 0;
}
- tcd->ssize = MPC_DMA_TSIZE_4;
- tcd->dsize = MPC_DMA_TSIZE_4;
+ tcd->ssize = buswidth_to_dmatsize(mchan->swidth);
+ tcd->dsize = buswidth_to_dmatsize(mchan->dwidth);
if (mdma->is_mpc8308) {
tcd->nbytes = sg_dma_len(sg);
- if (!IS_ALIGNED(tcd->nbytes, 4))
+ if (!IS_ALIGNED(tcd->nbytes, mchan->swidth))
goto err_prep;
/* No major loops for MPC8303 */
@@ -770,7 +788,7 @@ mpc_dma_prep_slave_sg(struct dma_chan *chan, struct scatterlist *sgl,
tcd->citer = 1;
} else {
len = sg_dma_len(sg);
- tcd->nbytes = tcd_nunits * 4;
+ tcd->nbytes = tcd_nunits * tcd->ssize;
if (!IS_ALIGNED(len, tcd->nbytes))
goto err_prep;
@@ -806,40 +824,62 @@ err_prep:
return NULL;
}
+inline bool is_buswidth_valid(u8 buswidth, bool is_mpc8308)
+{
+ switch (buswidth) {
+ case 16:
+ if (is_mpc8308)
+ return false;
+ case 1:
+ case 2:
+ case 4:
+ case 32:
+ break;
+ default:
+ return false;
+ }
+
+ return true;
+}
+
static int mpc_dma_device_config(struct dma_chan *chan,
struct dma_slave_config *cfg)
{
struct mpc_dma_chan *mchan = dma_chan_to_mpc_dma_chan(chan);
+ struct mpc_dma *mdma = dma_chan_to_mpc_dma(&mchan->chan);
unsigned long flags;
/*
* Software constraints:
- * - only transfers between a peripheral device and
- * memory are supported;
- * - only peripheral devices with 4-byte FIFO access register
- * are supported;
- * - minimal transfer chunk is 4 bytes and consequently
- * source and destination addresses must be 4-byte aligned
- * and transfer size must be aligned on (4 * maxburst)
- * boundary;
- * - during the transfer RAM address is being incremented by
- * the size of minimal transfer chunk;
- * - peripheral port's address is constant during the transfer.
+ * - only transfers between a peripheral device and memory are
+ * supported
+ * - transfer chunk sizes of 1, 2, 4, 16 (for MPC512x), and 32 bytes
+ * are supported, and, consequently, source addresses and
+ * destination addresses; must be aligned accordingly; furthermore,
+ * for MPC512x SoCs, the transfer size must be aligned on (chunk
+ * size * maxburst)
+ * - during the transfer, the RAM address is incremented by the size
+ * of transfer chunk
+ * - the peripheral port's address is constant during the transfer.
*/
- if (cfg->src_addr_width != DMA_SLAVE_BUSWIDTH_4_BYTES ||
- cfg->dst_addr_width != DMA_SLAVE_BUSWIDTH_4_BYTES ||
- !IS_ALIGNED(cfg->src_addr, 4) ||
- !IS_ALIGNED(cfg->dst_addr, 4)) {
+ if (!IS_ALIGNED(cfg->src_addr, cfg->src_addr_width) ||
+ !IS_ALIGNED(cfg->dst_addr, cfg->dst_addr_width)) {
return -EINVAL;
}
+ if (!is_buswidth_valid(cfg->src_addr_width, mdma->is_mpc8308) ||
+ !is_buswidth_valid(cfg->dst_addr_width, mdma->is_mpc8308))
+ return -EINVAL;
+
spin_lock_irqsave(&mchan->lock, flags);
mchan->src_per_paddr = cfg->src_addr;
mchan->src_tcd_nunits = cfg->src_maxburst;
+ mchan->swidth = cfg->src_addr_width;
mchan->dst_per_paddr = cfg->dst_addr;
mchan->dst_tcd_nunits = cfg->dst_maxburst;
+ mchan->dwidth = cfg->dst_addr_width;
/* Apply defaults */
if (mchan->src_tcd_nunits == 0)
--
1.8.3
--
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