[PATCH v3 2/2] dmaengine: Add support for multiple descriptors for imx-dma.
Javier Martin
javier.martin at vista-silicon.com
Fri Mar 2 03:28:47 EST 2012
dmaengine specifies the possibility that several descriptors
can be queued for transfer. It also indicates that tasklets
must be used for DMA callbacks.
Acked-by: Sascha Hauer <s.hauer at pengutronix.de>
Signed-off-by: Javier Martin <javier.martin at vista-silicon.com>
---
Added comment explaining fall through in 'imxdma_xfer_desc'.
---
drivers/dma/imx-dma.c | 332 ++++++++++++++++++++++++++++++++++++++-----------
1 files changed, 258 insertions(+), 74 deletions(-)
diff --git a/drivers/dma/imx-dma.c b/drivers/dma/imx-dma.c
index 9aa6e85..c32103f 100644
--- a/drivers/dma/imx-dma.c
+++ b/drivers/dma/imx-dma.c
@@ -5,6 +5,7 @@
* found on i.MX1/21/27
*
* Copyright 2010 Sascha Hauer, Pengutronix <s.hauer at pengutronix.de>
+ * Copyright 2012 Javier Martin, Vista Silicon <javier.martin at vista-silicon.com>
*
* The code contained herein is licensed under the GNU General Public
* License. You may obtain a copy of the GNU General Public License
@@ -13,6 +14,7 @@
* http://www.opensource.org/licenses/gpl-license.html
* http://www.gnu.org/copyleft/gpl.html
*/
+
#include <linux/init.h>
#include <linux/module.h>
#include <linux/types.h>
@@ -30,19 +32,52 @@
#include <mach/dma-v1.h>
#include <mach/hardware.h>
+#define IMXDMA_MAX_CHAN_DESCRIPTORS 16
+
+enum imxdma_prep_type {
+ IMXDMA_DESC_MEMCPY,
+ IMXDMA_DESC_INTERLEAVED,
+ IMXDMA_DESC_SLAVE_SG,
+ IMXDMA_DESC_CYCLIC,
+};
+
+struct imxdma_desc {
+ struct list_head node;
+ struct dma_async_tx_descriptor desc;
+ enum dma_status status;
+ dma_addr_t src;
+ dma_addr_t dest;
+ size_t len;
+ unsigned int dmamode;
+ enum imxdma_prep_type type;
+ /* For memcpy and interleaved */
+ unsigned int config_port;
+ unsigned int config_mem;
+ /* For interleaved transfers */
+ unsigned int x;
+ unsigned int y;
+ unsigned int w;
+ /* For slave sg and cyclic */
+ struct scatterlist *sg;
+ unsigned int sgcount;
+};
+
struct imxdma_channel {
struct imxdma_engine *imxdma;
unsigned int channel;
unsigned int imxdma_channel;
+ struct tasklet_struct dma_tasklet;
+ struct list_head ld_free;
+ struct list_head ld_queue;
+ struct list_head ld_active;
+ int descs_allocated;
enum dma_slave_buswidth word_size;
dma_addr_t per_address;
u32 watermark_level;
struct dma_chan chan;
spinlock_t lock;
- struct dma_async_tx_descriptor desc;
dma_cookie_t last_completed;
- enum dma_status status;
int dma_request;
struct scatterlist *sg_list;
};
@@ -61,27 +96,31 @@ static struct imxdma_channel *to_imxdma_chan(struct dma_chan *chan)
return container_of(chan, struct imxdma_channel, chan);
}
-static void imxdma_handle(struct imxdma_channel *imxdmac)
+static inline bool imxdma_chan_is_doing_cyclic(struct imxdma_channel *imxdmac)
{
- if (imxdmac->desc.callback)
- imxdmac->desc.callback(imxdmac->desc.callback_param);
- imxdmac->last_completed = imxdmac->desc.cookie;
+ struct imxdma_desc *desc;
+
+ if (!list_empty(&imxdmac->ld_active)) {
+ desc = list_first_entry(&imxdmac->ld_active, struct imxdma_desc,
+ node);
+ if (desc->type == IMXDMA_DESC_CYCLIC)
+ return true;
+ }
+ return false;
}
static void imxdma_irq_handler(int channel, void *data)
{
struct imxdma_channel *imxdmac = data;
- imxdmac->status = DMA_SUCCESS;
- imxdma_handle(imxdmac);
+ tasklet_schedule(&imxdmac->dma_tasklet);
}
static void imxdma_err_handler(int channel, void *data, int error)
{
struct imxdma_channel *imxdmac = data;
- imxdmac->status = DMA_ERROR;
- imxdma_handle(imxdmac);
+ tasklet_schedule(&imxdmac->dma_tasklet);
}
static void imxdma_progression(int channel, void *data,
@@ -89,8 +128,88 @@ static void imxdma_progression(int channel, void *data,
{
struct imxdma_channel *imxdmac = data;
- imxdmac->status = DMA_SUCCESS;
- imxdma_handle(imxdmac);
+ tasklet_schedule(&imxdmac->dma_tasklet);
+}
+
+static int imxdma_xfer_desc(struct imxdma_desc *d)
+{
+ struct imxdma_channel *imxdmac = to_imxdma_chan(d->desc.chan);
+ int ret;
+
+ /* Configure and enable */
+ switch (d->type) {
+ case IMXDMA_DESC_MEMCPY:
+ ret = imx_dma_config_channel(imxdmac->imxdma_channel,
+ d->config_port, d->config_mem, 0, 0);
+ if (ret < 0)
+ return ret;
+ ret = imx_dma_setup_single(imxdmac->imxdma_channel, d->src,
+ d->len, d->dest, d->dmamode);
+ if (ret < 0)
+ return ret;
+ break;
+ case IMXDMA_DESC_CYCLIC:
+ ret = imx_dma_setup_progression_handler(imxdmac->imxdma_channel,
+ imxdma_progression);
+ if (ret < 0)
+ return ret;
+ /*
+ * We fall through here since cyclic transfer is the same as
+ * slave_sg adding a progression handler and a specific sg
+ * configuration which is done in 'imxdma_prep_dma_cyclic'.
+ */
+ case IMXDMA_DESC_SLAVE_SG:
+ if (d->dmamode == DMA_MODE_READ)
+ ret = imx_dma_setup_sg(imxdmac->imxdma_channel, d->sg,
+ d->sgcount, d->len, d->src, d->dmamode);
+ else
+ ret = imx_dma_setup_sg(imxdmac->imxdma_channel, d->sg,
+ d->sgcount, d->len, d->dest, d->dmamode);
+ if (ret < 0)
+ return ret;
+ break;
+ default:
+ return -EINVAL;
+ }
+ imx_dma_enable(imxdmac->imxdma_channel);
+ return 0;
+}
+
+static void imxdma_tasklet(unsigned long data)
+{
+ struct imxdma_channel *imxdmac = (void *)data;
+ struct imxdma_engine *imxdma = imxdmac->imxdma;
+ struct imxdma_desc *desc;
+
+ spin_lock(&imxdmac->lock);
+
+ if (list_empty(&imxdmac->ld_active)) {
+ /* Someone might have called terminate all */
+ goto out;
+ }
+ desc = list_first_entry(&imxdmac->ld_active, struct imxdma_desc, node);
+
+ if (desc->desc.callback)
+ desc->desc.callback(desc->desc.callback_param);
+
+ imxdmac->last_completed = desc->desc.cookie;
+
+ /* If we are dealing with a cyclic descriptor keep it on ld_active */
+ if (imxdma_chan_is_doing_cyclic(imxdmac))
+ goto out;
+
+ list_move_tail(imxdmac->ld_active.next, &imxdmac->ld_free);
+
+ if (!list_empty(&imxdmac->ld_queue)) {
+ desc = list_first_entry(&imxdmac->ld_queue, struct imxdma_desc,
+ node);
+ list_move_tail(imxdmac->ld_queue.next, &imxdmac->ld_active);
+ if (imxdma_xfer_desc(desc) < 0)
+ dev_warn(imxdma->dev, "%s: channel: %d couldn't xfer desc\n",
+ __func__, imxdmac->channel);
+ }
+out:
+ spin_unlock(&imxdmac->lock);
}
static int imxdma_control(struct dma_chan *chan, enum dma_ctrl_cmd cmd,
@@ -99,12 +218,17 @@ static int imxdma_control(struct dma_chan *chan, enum dma_ctrl_cmd cmd,
struct imxdma_channel *imxdmac = to_imxdma_chan(chan);
struct dma_slave_config *dmaengine_cfg = (void *)arg;
int ret;
+ unsigned long flags;
unsigned int mode = 0;
switch (cmd) {
case DMA_TERMINATE_ALL:
- imxdmac->status = DMA_ERROR;
imx_dma_disable(imxdmac->imxdma_channel);
+
+ spin_lock_irqsave(&imxdmac->lock, flags);
+ list_splice_tail_init(&imxdmac->ld_active, &imxdmac->ld_free);
+ list_splice_tail_init(&imxdmac->ld_queue, &imxdmac->ld_free);
+ spin_unlock_irqrestore(&imxdmac->lock, flags);
return 0;
case DMA_SLAVE_CONFIG:
if (dmaengine_cfg->direction == DMA_DEV_TO_MEM) {
@@ -155,11 +279,14 @@ static enum dma_status imxdma_tx_status(struct dma_chan *chan,
struct imxdma_channel *imxdmac = to_imxdma_chan(chan);
dma_cookie_t last_used;
enum dma_status ret;
+ unsigned long flags;
+ spin_lock_irqsave(&imxdmac->lock, flags);
last_used = chan->cookie;
ret = dma_async_is_complete(cookie, imxdmac->last_completed, last_used);
dma_set_tx_state(txstate, imxdmac->last_completed, last_used, 0);
+ spin_unlock_irqrestore(&imxdmac->lock, flags);
return ret;
}
@@ -172,7 +299,6 @@ static dma_cookie_t imxdma_assign_cookie(struct imxdma_channel *imxdma)
cookie = 1;
imxdma->chan.cookie = cookie;
- imxdma->desc.cookie = cookie;
return cookie;
}
@@ -181,12 +307,15 @@ static dma_cookie_t imxdma_tx_submit(struct dma_async_tx_descriptor *tx)
{
struct imxdma_channel *imxdmac = to_imxdma_chan(tx->chan);
dma_cookie_t cookie;
+ unsigned long flags;
- spin_lock_irq(&imxdmac->lock);
+ spin_lock_irqsave(&imxdmac->lock, flags);
+ list_move_tail(imxdmac->ld_free.next, &imxdmac->ld_queue);
cookie = imxdma_assign_cookie(imxdmac);
+ tx->cookie = cookie;
- spin_unlock_irq(&imxdmac->lock);
+ spin_unlock_irqrestore(&imxdmac->lock, flags);
return cookie;
}
@@ -199,21 +328,48 @@ static int imxdma_alloc_chan_resources(struct dma_chan *chan)
if (data != NULL)
imxdmac->dma_request = data->dma_request;
- dma_async_tx_descriptor_init(&imxdmac->desc, chan);
- imxdmac->desc.tx_submit = imxdma_tx_submit;
- /* txd.flags will be overwritten in prep funcs */
- imxdmac->desc.flags = DMA_CTRL_ACK;
+ while (imxdmac->descs_allocated < IMXDMA_MAX_CHAN_DESCRIPTORS) {
+ struct imxdma_desc *desc;
- imxdmac->status = DMA_SUCCESS;
+ desc = kzalloc(sizeof(*desc), GFP_KERNEL);
+ if (!desc)
+ break;
+ __memzero(&desc->desc, sizeof(struct dma_async_tx_descriptor));
+ dma_async_tx_descriptor_init(&desc->desc, chan);
+ desc->desc.tx_submit = imxdma_tx_submit;
+ /* txd.flags will be overwritten in prep funcs */
+ desc->desc.flags = DMA_CTRL_ACK;
+ desc->status = DMA_SUCCESS;
+
+ list_add_tail(&desc->node, &imxdmac->ld_free);
+ imxdmac->descs_allocated++;
+ }
- return 0;
+ if (!imxdmac->descs_allocated)
+ return -ENOMEM;
+
+ return imxdmac->descs_allocated;
}
static void imxdma_free_chan_resources(struct dma_chan *chan)
{
struct imxdma_channel *imxdmac = to_imxdma_chan(chan);
+ struct imxdma_desc *desc, *_desc;
+ unsigned long flags;
+
+ spin_lock_irqsave(&imxdmac->lock, flags);
imx_dma_disable(imxdmac->imxdma_channel);
+ list_splice_tail_init(&imxdmac->ld_active, &imxdmac->ld_free);
+ list_splice_tail_init(&imxdmac->ld_queue, &imxdmac->ld_free);
+
+ spin_unlock_irqrestore(&imxdmac->lock, flags);
+
+ list_for_each_entry_safe(desc, _desc, &imxdmac->ld_free, node) {
+ kfree(desc);
+ imxdmac->descs_allocated--;
+ }
+ INIT_LIST_HEAD(&imxdmac->ld_free);
if (imxdmac->sg_list) {
kfree(imxdmac->sg_list);
@@ -228,23 +384,19 @@ static struct dma_async_tx_descriptor *imxdma_prep_slave_sg(
{
struct imxdma_channel *imxdmac = to_imxdma_chan(chan);
struct scatterlist *sg;
- int i, ret, dma_length = 0;
- unsigned int dmamode;
+ int i, dma_length = 0;
+ struct imxdma_desc *desc;
- if (imxdmac->status == DMA_IN_PROGRESS)
+ if (list_empty(&imxdmac->ld_free) ||
+ imxdma_chan_is_doing_cyclic(imxdmac))
return NULL;
- imxdmac->status = DMA_IN_PROGRESS;
+ desc = list_first_entry(&imxdmac->ld_free, struct imxdma_desc, node);
for_each_sg(sgl, sg, sg_len, i) {
dma_length += sg->length;
}
- if (direction == DMA_DEV_TO_MEM)
- dmamode = DMA_MODE_READ;
- else
- dmamode = DMA_MODE_WRITE;
-
switch (imxdmac->word_size) {
case DMA_SLAVE_BUSWIDTH_4_BYTES:
if (sgl->length & 3 || sgl->dma_address & 3)
@@ -260,12 +412,21 @@ static struct dma_async_tx_descriptor *imxdma_prep_slave_sg(
return NULL;
}
- ret = imx_dma_setup_sg(imxdmac->imxdma_channel, sgl, sg_len,
- dma_length, imxdmac->per_address, dmamode);
- if (ret)
- return NULL;
+ desc->type = IMXDMA_DESC_SLAVE_SG;
+ desc->sg = sgl;
+ desc->sgcount = sg_len;
+ desc->len = dma_length;
+ if (direction == DMA_DEV_TO_MEM) {
+ desc->dmamode = DMA_MODE_READ;
+ desc->src = imxdmac->per_address;
+ } else {
+ desc->dmamode = DMA_MODE_WRITE;
+ desc->dest = imxdmac->per_address;
+ }
+ desc->desc.callback = NULL;
+ desc->desc.callback_param = NULL;
- return &imxdmac->desc;
+ return &desc->desc;
}
static struct dma_async_tx_descriptor *imxdma_prep_dma_cyclic(
@@ -274,23 +435,18 @@ static struct dma_async_tx_descriptor *imxdma_prep_dma_cyclic(
{
struct imxdma_channel *imxdmac = to_imxdma_chan(chan);
struct imxdma_engine *imxdma = imxdmac->imxdma;
- int i, ret;
+ struct imxdma_desc *desc;
+ int i;
unsigned int periods = buf_len / period_len;
- unsigned int dmamode;
dev_dbg(imxdma->dev, "%s channel: %d buf_len=%d period_len=%d\n",
__func__, imxdmac->channel, buf_len, period_len);
- if (imxdmac->status == DMA_IN_PROGRESS)
+ if (list_empty(&imxdmac->ld_free) ||
+ imxdma_chan_is_doing_cyclic(imxdmac))
return NULL;
- imxdmac->status = DMA_IN_PROGRESS;
- ret = imx_dma_setup_progression_handler(imxdmac->imxdma_channel,
- imxdma_progression);
- if (ret) {
- dev_err(imxdma->dev, "Failed to setup the DMA handler\n");
- return NULL;
- }
+ desc = list_first_entry(&imxdmac->ld_free, struct imxdma_desc, node);
if (imxdmac->sg_list)
kfree(imxdmac->sg_list);
@@ -316,17 +472,21 @@ static struct dma_async_tx_descriptor *imxdma_prep_dma_cyclic(
imxdmac->sg_list[periods].page_link =
((unsigned long)imxdmac->sg_list | 0x01) & ~0x02;
- if (direction == DMA_DEV_TO_MEM)
- dmamode = DMA_MODE_READ;
- else
- dmamode = DMA_MODE_WRITE;
-
- ret = imx_dma_setup_sg(imxdmac->imxdma_channel, imxdmac->sg_list, periods,
- IMX_DMA_LENGTH_LOOP, imxdmac->per_address, dmamode);
- if (ret)
- return NULL;
+ desc->type = IMXDMA_DESC_CYCLIC;
+ desc->sg = imxdmac->sg_list;
+ desc->sgcount = periods;
+ desc->len = IMX_DMA_LENGTH_LOOP;
+ if (direction == DMA_DEV_TO_MEM) {
+ desc->dmamode = DMA_MODE_READ;
+ desc->src = imxdmac->per_address;
+ } else {
+ desc->dmamode = DMA_MODE_WRITE;
+ desc->dest = imxdmac->per_address;
+ }
+ desc->desc.callback = NULL;
+ desc->desc.callback_param = NULL;
- return &imxdmac->desc;
+ return &desc->desc;
}
static struct dma_async_tx_descriptor *imxdma_prep_dma_memcpy(
@@ -335,36 +495,53 @@ static struct dma_async_tx_descriptor *imxdma_prep_dma_memcpy(
{
struct imxdma_channel *imxdmac = to_imxdma_chan(chan);
struct imxdma_engine *imxdma = imxdmac->imxdma;
- int ret;
+ struct imxdma_desc *desc;
dev_dbg(imxdma->dev, "%s channel: %d src=0x%x dst=0x%x len=%d\n",
__func__, imxdmac->channel, src, dest, len);
- if (imxdmac->status == DMA_IN_PROGRESS)
+ if (list_empty(&imxdmac->ld_free) ||
+ imxdma_chan_is_doing_cyclic(imxdmac))
return NULL;
- imxdmac->status = DMA_IN_PROGRESS;
- ret = imx_dma_config_channel(imxdmac->imxdma_channel,
- IMX_DMA_MEMSIZE_32 | IMX_DMA_TYPE_LINEAR,
- IMX_DMA_MEMSIZE_32 | IMX_DMA_TYPE_LINEAR,
- 0, 0);
- if (ret)
- return NULL;
+ desc = list_first_entry(&imxdmac->ld_free, struct imxdma_desc, node);
- ret = imx_dma_setup_single(imxdmac->imxdma_channel, src, len,
- dest, DMA_MODE_WRITE);
- if (ret)
- return NULL;
+ desc->type = IMXDMA_DESC_MEMCPY;
+ desc->src = src;
+ desc->dest = dest;
+ desc->len = len;
+ desc->dmamode = DMA_MODE_WRITE;
+ desc->config_port = IMX_DMA_MEMSIZE_32 | IMX_DMA_TYPE_LINEAR;
+ desc->config_mem = IMX_DMA_MEMSIZE_32 | IMX_DMA_TYPE_LINEAR;
+ desc->desc.callback = NULL;
+ desc->desc.callback_param = NULL;
- return &imxdmac->desc;
+ return &desc->desc;
}
static void imxdma_issue_pending(struct dma_chan *chan)
{
struct imxdma_channel *imxdmac = to_imxdma_chan(chan);
-
- if (imxdmac->status == DMA_IN_PROGRESS)
- imx_dma_enable(imxdmac->imxdma_channel);
+ struct imxdma_engine *imxdma = imxdmac->imxdma;
+ struct imxdma_desc *desc;
+ unsigned long flags;
+
+ spin_lock_irqsave(&imxdmac->lock, flags);
+ if (list_empty(&imxdmac->ld_active) &&
+ !list_empty(&imxdmac->ld_queue)) {
+ desc = list_first_entry(&imxdmac->ld_queue,
+ struct imxdma_desc, node);
+
+ if (imxdma_xfer_desc(desc) < 0) {
+ dev_warn(imxdma->dev,
+ "%s: channel: %d couldn't issue DMA xfer\n",
+ __func__, imxdmac->channel);
+ } else {
+ list_move_tail(imxdmac->ld_queue.next,
+ &imxdmac->ld_active);
+ }
+ }
+ spin_unlock_irqrestore(&imxdmac->lock, flags);
}
static int __init imxdma_probe(struct platform_device *pdev)
@@ -399,11 +576,18 @@ static int __init imxdma_probe(struct platform_device *pdev)
imxdmac->imxdma = imxdma;
spin_lock_init(&imxdmac->lock);
+ INIT_LIST_HEAD(&imxdmac->ld_queue);
+ INIT_LIST_HEAD(&imxdmac->ld_free);
+ INIT_LIST_HEAD(&imxdmac->ld_active);
+
+ tasklet_init(&imxdmac->dma_tasklet, imxdma_tasklet,
+ (unsigned long)imxdmac);
imxdmac->chan.device = &imxdma->dma_device;
imxdmac->channel = i;
/* Add the channel to the DMAC list */
- list_add_tail(&imxdmac->chan.device_node, &imxdma->dma_device.channels);
+ list_add_tail(&imxdmac->chan.device_node,
+ &imxdma->dma_device.channels);
}
imxdma->dev = &pdev->dev;
--
1.7.0.4
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