[V2 1/2] powerpc: mpc512x_dma: add support for data transfers between memory and i/o memory
Alexander Popov
a13xp0p0v88 at gmail.com
Wed Jul 10 20:20:51 EST 2013
Data transfers between memory and i/o memory require more delicate TCD
(Transfer Control Descriptor) configuration and DMA channel service requests
via hardware.
dma_device.device_control callback function is needed to configure
DMA channel to work with i/o memory.
Signed-off-by: Alexander Popov <a13xp0p0v88 at gmail.com>
---
drivers/dma/mpc512x_dma.c | 147 +++++++++++++++++++++++++++++++++++++++++++---
1 file changed, 140 insertions(+), 7 deletions(-)
diff --git a/drivers/dma/mpc512x_dma.c b/drivers/dma/mpc512x_dma.c
index 2d95673..f90b717 100644
--- a/drivers/dma/mpc512x_dma.c
+++ b/drivers/dma/mpc512x_dma.c
@@ -2,6 +2,7 @@
* Copyright (C) Freescale Semicondutor, Inc. 2007, 2008.
* Copyright (C) Semihalf 2009
* Copyright (C) Ilya Yanok, Emcraft Systems 2010
+ * Copyright (C) Alexander Popov, Promcontroller 2013
*
* Written by Piotr Ziecik <kosmo at semihalf.com>. Hardware description
* (defines, structures and comments) was taken from MPC5121 DMA driver
@@ -28,11 +29,6 @@
* file called COPYING.
*/
-/*
- * This is initial version of MPC5121 DMA driver. Only memory to memory
- * transfers are supported (tested using dmatest module).
- */
-
#include <linux/module.h>
#include <linux/dmaengine.h>
#include <linux/dma-mapping.h>
@@ -190,9 +186,13 @@ struct mpc_dma_chan {
struct list_head completed;
struct mpc_dma_tcd *tcd;
dma_addr_t tcd_paddr;
+ u32 tcd_nunits;
/* Lock for this structure */
spinlock_t lock;
+
+ /* Channel's peripheral fifo address */
+ dma_addr_t per_paddr;
};
struct mpc_dma {
@@ -256,7 +256,9 @@ static void mpc_dma_execute(struct mpc_dma_chan *mchan)
prev->tcd->dlast_sga = mdesc->tcd_paddr;
prev->tcd->e_sg = 1;
- mdesc->tcd->start = 1;
+ /* only start explicitly on MDDRC channel */
+ if (cid == 32)
+ mdesc->tcd->start = 1;
prev = mdesc;
}
@@ -268,7 +270,15 @@ static void mpc_dma_execute(struct mpc_dma_chan *mchan)
if (first != prev)
mdma->tcd[cid].e_sg = 1;
- out_8(&mdma->regs->dmassrt, cid);
+
+ switch (cid) {
+ case 26:
+ out_8(&mdma->regs->dmaserq, cid);
+ break;
+ case 32:
+ out_8(&mdma->regs->dmassrt, cid);
+ break;
+ }
}
/* Handle interrupt on one half of DMA controller (32 channels) */
@@ -641,6 +651,126 @@ mpc_dma_prep_memcpy(struct dma_chan *chan, dma_addr_t dst, dma_addr_t src,
return &mdesc->desc;
}
+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,
+ unsigned long flags, void *context)
+{
+ struct mpc_dma *mdma = dma_chan_to_mpc_dma(chan);
+ struct mpc_dma_chan *mchan = dma_chan_to_mpc_dma_chan(chan);
+ struct mpc_dma_desc *mdesc = NULL;
+ struct mpc_dma_tcd *tcd;
+ unsigned long iflags;
+ struct scatterlist *sg;
+ size_t len;
+ int iter, i;
+
+ if (!list_empty(&mchan->active))
+ return NULL;
+
+ for_each_sg(sgl, sg, sg_len, i) {
+ spin_lock_irqsave(&mchan->lock, iflags);
+
+ mdesc = list_first_entry(&mchan->free, struct mpc_dma_desc,
+ node);
+ if (!mdesc) {
+ spin_unlock_irqrestore(&mchan->lock, iflags);
+ /* try to free completed descriptors */
+ mpc_dma_process_completed(mdma);
+ return NULL;
+ }
+
+ list_del(&mdesc->node);
+
+ spin_unlock_irqrestore(&mchan->lock, iflags);
+
+ mdesc->error = 0;
+ tcd = mdesc->tcd;
+
+ /* Prepare Transfer Control Descriptor for this transaction */
+ memset(tcd, 0, sizeof(struct mpc_dma_tcd));
+
+ if (!IS_ALIGNED(sg_dma_address(sg), 4))
+ return NULL;
+
+ if (direction == DMA_DEV_TO_MEM) {
+ tcd->saddr = mchan->per_paddr;
+ tcd->daddr = sg_dma_address(sg);
+ tcd->soff = 0;
+ tcd->doff = 4;
+ } else if (direction == DMA_MEM_TO_DEV) {
+ tcd->saddr = sg_dma_address(sg);
+ tcd->daddr = mchan->per_paddr;
+ tcd->soff = 4;
+ tcd->doff = 0;
+ } else {
+ return NULL;
+ }
+ tcd->ssize = MPC_DMA_TSIZE_4;
+ tcd->dsize = MPC_DMA_TSIZE_4;
+
+ len = sg_dma_len(sg);
+
+ if (mchan->tcd_nunits)
+ tcd->nbytes = mchan->tcd_nunits * 4;
+ else
+ tcd->nbytes = 64;
+
+ if (!IS_ALIGNED(len, tcd->nbytes))
+ return NULL;
+
+ iter = len / tcd->nbytes;
+ if (iter > ((1 << 15) - 1)) { /* maximum biter */
+ return NULL; /* len is too big */
+ } else {
+ /* citer_linkch contains the high bits of iter */
+ tcd->biter = iter & 0x1ff;
+ tcd->biter_linkch = iter >> 9;
+ tcd->citer = tcd->biter;
+ tcd->citer_linkch = tcd->biter_linkch;
+ }
+
+ tcd->e_sg = 0;
+ tcd->d_req = 1;
+
+ /* Place descriptor in prepared list */
+ spin_lock_irqsave(&mchan->lock, iflags);
+ list_add_tail(&mdesc->node, &mchan->prepared);
+ spin_unlock_irqrestore(&mchan->lock, iflags);
+ }
+
+ /* Return the last descriptor */
+ return &mdesc->desc;
+}
+
+static int mpc_dma_device_control(struct dma_chan *chan, enum dma_ctrl_cmd cmd,
+ unsigned long arg)
+{
+ struct mpc_dma_chan *mchan = dma_chan_to_mpc_dma_chan(chan);
+ struct dma_slave_config *cfg = (void *)arg;
+
+ switch (cmd) {
+ case DMA_SLAVE_CONFIG:
+ if (cfg->src_addr_width != DMA_SLAVE_BUSWIDTH_4_BYTES &&
+ cfg->dst_addr_width != DMA_SLAVE_BUSWIDTH_4_BYTES)
+ return -EINVAL;
+
+ if (cfg->direction == DMA_DEV_TO_MEM) {
+ mchan->per_paddr = cfg->src_addr;
+ mchan->tcd_nunits = cfg->src_maxburst;
+ } else {
+ mchan->per_paddr = cfg->dst_addr;
+ mchan->tcd_nunits = cfg->dst_maxburst;
+ }
+
+ return 0;
+ default:
+ return -ENOSYS;
+ }
+
+ return -EINVAL;
+}
+
static int mpc_dma_probe(struct platform_device *op)
{
struct device_node *dn = op->dev.of_node;
@@ -725,9 +855,12 @@ static int mpc_dma_probe(struct platform_device *op)
dma->device_issue_pending = mpc_dma_issue_pending;
dma->device_tx_status = mpc_dma_tx_status;
dma->device_prep_dma_memcpy = mpc_dma_prep_memcpy;
+ dma->device_prep_slave_sg = mpc_dma_prep_slave_sg;
+ dma->device_control = mpc_dma_device_control;
INIT_LIST_HEAD(&dma->channels);
dma_cap_set(DMA_MEMCPY, dma->cap_mask);
+ dma_cap_set(DMA_SLAVE, dma->cap_mask);
for (i = 0; i < dma->chancnt; i++) {
mchan = &mdma->channels[i];
--
1.7.11.3
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