Split the virtual slave channel DMA support from the sa11x0 driver so
this code can be shared with other slave DMA engine drivers.
Acked-by: Linus Walleij <linus.walleij@xxxxxxxxxx>
Signed-off-by: Russell King <rmk+kernel@xxxxxxxxxxxxxxxx>
---
drivers/dma/Kconfig | 4 +
drivers/dma/Makefile | 1 +
drivers/dma/sa11x0-dma.c | 249 ++++++++++++++-------------------------------
drivers/dma/virt-dma.c | 99 ++++++++++++++++++
drivers/dma/virt-dma.h | 138 +++++++++++++++++++++++++
5 files changed, 320 insertions(+), 171 deletions(-)
create mode 100644 drivers/dma/virt-dma.c
create mode 100644 drivers/dma/virt-dma.h
diff --git a/drivers/dma/Kconfig b/drivers/dma/Kconfig
index aadeb5b..eb2b60e 100644
--- a/drivers/dma/Kconfig
+++ b/drivers/dma/Kconfig
@@ -255,6 +255,7 @@ config DMA_SA11X0
tristate "SA-11x0 DMA support"
depends on ARCH_SA1100
select DMA_ENGINE
+ select DMA_VIRTUAL_CHANNELS
help
Support the DMA engine found on Intel StrongARM SA-1100 and
SA-1110 SoCs. This DMA engine can only be used with on-chip
@@ -263,6 +264,9 @@ config DMA_SA11X0
config DMA_ENGINE
bool
+config DMA_VIRTUAL_CHANNELS
+ tristate
+
comment "DMA Clients"
depends on DMA_ENGINE
diff --git a/drivers/dma/Makefile b/drivers/dma/Makefile
index 86b795b..fc05f7d 100644
--- a/drivers/dma/Makefile
+++ b/drivers/dma/Makefile
@@ -2,6 +2,7 @@ ccflags-$(CONFIG_DMADEVICES_DEBUG) := -DDEBUG
ccflags-$(CONFIG_DMADEVICES_VDEBUG) += -DVERBOSE_DEBUG
obj-$(CONFIG_DMA_ENGINE) += dmaengine.o
+obj-$(CONFIG_DMA_VIRTUAL_CHANNELS) += virt-dma.o
obj-$(CONFIG_NET_DMA) += iovlock.o
obj-$(CONFIG_INTEL_MID_DMAC) += intel_mid_dma.o
obj-$(CONFIG_DMATEST) += dmatest.o
diff --git a/drivers/dma/sa11x0-dma.c b/drivers/dma/sa11x0-dma.c
index ec78cce..5f1d2e6 100644
--- a/drivers/dma/sa11x0-dma.c
+++ b/drivers/dma/sa11x0-dma.c
@@ -21,6 +21,8 @@
#include <linux/slab.h>
#include <linux/spinlock.h>
+#include "virt-dma.h"
+
#define NR_PHY_CHAN 6
#define DMA_ALIGN 3
#define DMA_MAX_SIZE 0x1fff
@@ -72,12 +74,11 @@ struct sa11x0_dma_sg {
};
struct sa11x0_dma_desc {
- struct dma_async_tx_descriptor tx;
+ struct virt_dma_desc vd;
+
u32 ddar;
size_t size;
- /* maybe protected by c->lock */
- struct list_head node;
unsigned sglen;
struct sa11x0_dma_sg sg[0];
};
@@ -85,15 +86,11 @@ struct sa11x0_dma_desc {
struct sa11x0_dma_phy;
struct sa11x0_dma_chan {
- struct dma_chan chan;
- spinlock_t lock;
- dma_cookie_t lc;
+ struct virt_dma_chan vc;
- /* protected by c->lock */
+ /* protected by c->vc.lock */
struct sa11x0_dma_phy *phy;
enum dma_status status;
- struct list_head desc_submitted;
- struct list_head desc_issued;
/* protected by d->lock */
struct list_head node;
@@ -109,7 +106,7 @@ struct sa11x0_dma_phy {
struct sa11x0_dma_chan *vchan;
- /* Protected by c->lock */
+ /* Protected by c->vc.lock */
unsigned sg_load;
struct sa11x0_dma_desc *txd_load;
unsigned sg_done;
@@ -127,13 +124,12 @@ struct sa11x0_dma_dev {
spinlock_t lock;
struct tasklet_struct task;
struct list_head chan_pending;
- struct list_head desc_complete;
struct sa11x0_dma_phy phy[NR_PHY_CHAN];
};
static struct sa11x0_dma_chan *to_sa11x0_dma_chan(struct dma_chan *chan)
{
- return container_of(chan, struct sa11x0_dma_chan, chan);
+ return container_of(chan, struct sa11x0_dma_chan, vc.chan);
}
static struct sa11x0_dma_dev *to_sa11x0_dma(struct dma_device *dmadev)
@@ -141,27 +137,26 @@ static struct sa11x0_dma_dev *to_sa11x0_dma(struct dma_device *dmadev)
return container_of(dmadev, struct sa11x0_dma_dev, slave);
}
-static struct sa11x0_dma_desc *to_sa11x0_dma_tx(struct dma_async_tx_descriptor *tx)
+static struct sa11x0_dma_desc *sa11x0_dma_next_desc(struct sa11x0_dma_chan *c)
{
- return container_of(tx, struct sa11x0_dma_desc, tx);
+ struct virt_dma_desc *vd = vchan_next_desc(&c->vc);
+
+ return vd ? container_of(vd, struct sa11x0_dma_desc, vd) : NULL;
}
-static struct sa11x0_dma_desc *sa11x0_dma_next_desc(struct sa11x0_dma_chan *c)
+static void sa11x0_dma_free_desc(struct virt_dma_desc *vd)
{
- if (list_empty(&c->desc_issued))
- return NULL;
-
- return list_first_entry(&c->desc_issued, struct sa11x0_dma_desc, node);
+ kfree(container_of(vd, struct sa11x0_dma_desc, vd));
}
static void sa11x0_dma_start_desc(struct sa11x0_dma_phy *p, struct sa11x0_dma_desc *txd)
{
- list_del(&txd->node);
+ list_del(&txd->vd.node);
p->txd_load = txd;
p->sg_load = 0;
dev_vdbg(p->dev->slave.dev, "pchan %u: txd %p[%x]: starting: DDAR:%x\n",
- p->num, txd, txd->tx.cookie, txd->ddar);
+ p->num, &txd->vd, txd->vd.tx.cookie, txd->ddar);
}
static void noinline sa11x0_dma_start_sg(struct sa11x0_dma_phy *p,
@@ -229,21 +224,13 @@ static void noinline sa11x0_dma_complete(struct sa11x0_dma_phy *p,
struct sa11x0_dma_desc *txd = p->txd_done;
if (++p->sg_done == txd->sglen) {
- struct sa11x0_dma_dev *d = p->dev;
-
- dev_vdbg(d->slave.dev, "pchan %u: txd %p[%x]: completed\n",
- p->num, p->txd_done, p->txd_done->tx.cookie);
-
- c->lc = txd->tx.cookie;
-
- spin_lock(&d->lock);
- list_add_tail(&txd->node, &d->desc_complete);
- spin_unlock(&d->lock);
+ vchan_cookie_complete(&txd->vd);
p->sg_done = 0;
p->txd_done = p->txd_load;
- tasklet_schedule(&d->task);
+ if (!p->txd_done)
+ tasklet_schedule(&p->dev->task);
}
sa11x0_dma_start_sg(p, c);
@@ -280,7 +267,7 @@ static irqreturn_t sa11x0_dma_irq(int irq, void *dev_id)
if (c) {
unsigned long flags;
- spin_lock_irqsave(&c->lock, flags);
+ spin_lock_irqsave(&c->vc.lock, flags);
/*
* Now that we're holding the lock, check that the vchan
* really is associated with this pchan before touching the
@@ -294,7 +281,7 @@ static irqreturn_t sa11x0_dma_irq(int irq, void *dev_id)
if (dcsr & DCSR_DONEB)
sa11x0_dma_complete(p, c);
}
- spin_unlock_irqrestore(&c->lock, flags);
+ spin_unlock_irqrestore(&c->vc.lock, flags);
}
return IRQ_HANDLED;
@@ -332,28 +319,15 @@ static void sa11x0_dma_tasklet(unsigned long arg)
struct sa11x0_dma_dev *d = (struct sa11x0_dma_dev *)arg;
struct sa11x0_dma_phy *p;
struct sa11x0_dma_chan *c;
- struct sa11x0_dma_desc *txd, *txn;
- LIST_HEAD(head);
unsigned pch, pch_alloc = 0;
dev_dbg(d->slave.dev, "tasklet enter\n");
- /* Get the completed tx descriptors */
- spin_lock_irq(&d->lock);
- list_splice_init(&d->desc_complete, &head);
- spin_unlock_irq(&d->lock);
-
- list_for_each_entry(txd, &head, node) {
- c = to_sa11x0_dma_chan(txd->tx.chan);
-
- dev_dbg(d->slave.dev, "vchan %p: txd %p[%x] completed\n",
- c, txd, txd->tx.cookie);
-
- spin_lock_irq(&c->lock);
+ list_for_each_entry(c, &d->slave.channels, vc.chan.device_node) {
+ spin_lock_irq(&c->vc.lock);
p = c->phy;
- if (p) {
- if (!p->txd_done)
- sa11x0_dma_start_txd(c);
+ if (p && !p->txd_done) {
+ sa11x0_dma_start_txd(c);
if (!p->txd_done) {
/* No current txd associated with this channel */
dev_dbg(d->slave.dev, "pchan %u: free\n", p->num);
@@ -363,7 +337,7 @@ static void sa11x0_dma_tasklet(unsigned long arg)
p->vchan = NULL;
}
}
- spin_unlock_irq(&c->lock);
+ spin_unlock_irq(&c->vc.lock);
}
spin_lock_irq(&d->lock);
@@ -380,7 +354,7 @@ static void sa11x0_dma_tasklet(unsigned long arg)
/* Mark this channel allocated */
p->vchan = c;
- dev_dbg(d->slave.dev, "pchan %u: alloc vchan %p\n", pch, c);
+ dev_dbg(d->slave.dev, "pchan %u: alloc vchan %p\n", pch, &c->vc);
}
}
spin_unlock_irq(&d->lock);
@@ -390,42 +364,18 @@ static void sa11x0_dma_tasklet(unsigned long arg)
p = &d->phy[pch];
c = p->vchan;
- spin_lock_irq(&c->lock);
+ spin_lock_irq(&c->vc.lock);
c->phy = p;
sa11x0_dma_start_txd(c);
- spin_unlock_irq(&c->lock);
+ spin_unlock_irq(&c->vc.lock);
}
}
- /* Now free the completed tx descriptor, and call their callbacks */
- list_for_each_entry_safe(txd, txn, &head, node) {
- dma_async_tx_callback callback = txd->tx.callback;
- void *callback_param = txd->tx.callback_param;
-
- dev_dbg(d->slave.dev, "txd %p[%x]: callback and free\n",
- txd, txd->tx.cookie);
-
- kfree(txd);
-
- if (callback)
- callback(callback_param);
- }
-
dev_dbg(d->slave.dev, "tasklet exit\n");
}
-static void sa11x0_dma_desc_free(struct sa11x0_dma_dev *d, struct list_head *head)
-{
- struct sa11x0_dma_desc *txd, *txn;
-
- list_for_each_entry_safe(txd, txn, head, node) {
- dev_dbg(d->slave.dev, "txd %p: freeing\n", txd);
- kfree(txd);
- }
-}
-
static int sa11x0_dma_alloc_chan_resources(struct dma_chan *chan)
{
return 0;
@@ -436,18 +386,12 @@ static void sa11x0_dma_free_chan_resources(struct dma_chan *chan)
struct sa11x0_dma_chan *c = to_sa11x0_dma_chan(chan);
struct sa11x0_dma_dev *d = to_sa11x0_dma(chan->device);
unsigned long flags;
- LIST_HEAD(head);
- spin_lock_irqsave(&c->lock, flags);
- spin_lock(&d->lock);
+ spin_lock_irqsave(&d->lock, flags);
list_del_init(&c->node);
- spin_unlock(&d->lock);
-
- list_splice_tail_init(&c->desc_submitted, &head);
- list_splice_tail_init(&c->desc_issued, &head);
- spin_unlock_irqrestore(&c->lock, flags);
+ spin_unlock_irqrestore(&d->lock, flags);
- sa11x0_dma_desc_free(d, &head);
+ vchan_free_chan_resources(&c->vc);
}
static dma_addr_t sa11x0_dma_pos(struct sa11x0_dma_phy *p)
@@ -473,21 +417,15 @@ static enum dma_status sa11x0_dma_tx_status(struct dma_chan *chan,
struct sa11x0_dma_dev *d = to_sa11x0_dma(chan->device);
struct sa11x0_dma_phy *p;
struct sa11x0_dma_desc *txd;
- dma_cookie_t last_used, last_complete;
unsigned long flags;
enum dma_status ret;
size_t bytes = 0;
- last_used = c->chan.cookie;
- last_complete = c->lc;
-
- ret = dma_async_is_complete(cookie, last_complete, last_used);
- if (ret == DMA_SUCCESS) {
- dma_set_tx_state(state, last_complete, last_used, 0);
+ ret = dma_cookie_status(&c->vc.chan, cookie, state);
+ if (ret == DMA_SUCCESS)
return ret;
- }
- spin_lock_irqsave(&c->lock, flags);
+ spin_lock_irqsave(&c->vc.lock, flags);
p = c->phy;
ret = c->status;
if (p) {
@@ -524,12 +462,13 @@ static enum dma_status sa11x0_dma_tx_status(struct dma_chan *chan,
if (txd != p->txd_load && p->txd_load)
bytes += p->txd_load->size;
}
- list_for_each_entry(txd, &c->desc_issued, node) {
+ list_for_each_entry(txd, &c->vc.desc_issued, vd.node) {
bytes += txd->size;
}
- spin_unlock_irqrestore(&c->lock, flags);
+ spin_unlock_irqrestore(&c->vc.lock, flags);
- dma_set_tx_state(state, last_complete, last_used, bytes);
+ if (state)
+ state->residue = bytes;
dev_vdbg(d->slave.dev, "tx_status: bytes 0x%zx\n", bytes);
@@ -547,40 +486,20 @@ static void sa11x0_dma_issue_pending(struct dma_chan *chan)
struct sa11x0_dma_dev *d = to_sa11x0_dma(chan->device);
unsigned long flags;
- spin_lock_irqsave(&c->lock, flags);
- list_splice_tail_init(&c->desc_submitted, &c->desc_issued);
- if (!list_empty(&c->desc_issued)) {
- spin_lock(&d->lock);
- if (!c->phy && list_empty(&c->node)) {
- list_add_tail(&c->node, &d->chan_pending);
- tasklet_schedule(&d->task);
- dev_dbg(d->slave.dev, "vchan %p: issued\n", c);
+ spin_lock_irqsave(&c->vc.lock, flags);
+ if (vchan_issue_pending(&c->vc)) {
+ if (!c->phy) {
+ spin_lock(&d->lock);
+ if (list_empty(&c->node)) {
+ list_add_tail(&c->node, &d->chan_pending);
+ tasklet_schedule(&d->task);
+ dev_dbg(d->slave.dev, "vchan %p: issued\n", &c->vc);
+ }
+ spin_unlock(&d->lock);
}
- spin_unlock(&d->lock);
} else
- dev_dbg(d->slave.dev, "vchan %p: nothing to issue\n", c);
- spin_unlock_irqrestore(&c->lock, flags);
-}
-
-static dma_cookie_t sa11x0_dma_tx_submit(struct dma_async_tx_descriptor *tx)
-{
- struct sa11x0_dma_chan *c = to_sa11x0_dma_chan(tx->chan);
- struct sa11x0_dma_desc *txd = to_sa11x0_dma_tx(tx);
- unsigned long flags;
-
- spin_lock_irqsave(&c->lock, flags);
- c->chan.cookie += 1;
- if (c->chan.cookie < 0)
- c->chan.cookie = 1;
- txd->tx.cookie = c->chan.cookie;
-
- list_add_tail(&txd->node, &c->desc_submitted);
- spin_unlock_irqrestore(&c->lock, flags);
-
- dev_dbg(tx->chan->device->dev, "vchan %p: txd %p[%x]: submitted\n",
- c, txd, txd->tx.cookie);
-
- return txd->tx.cookie;
+ dev_dbg(d->slave.dev, "vchan %p: nothing to issue\n", &c->vc);
+ spin_unlock_irqrestore(&c->vc.lock, flags);
}
static struct dma_async_tx_descriptor *sa11x0_dma_prep_slave_sg(
@@ -596,7 +515,7 @@ static struct dma_async_tx_descriptor *sa11x0_dma_prep_slave_sg(
/* SA11x0 channels can only operate in their native direction */
if (dir != (c->ddar & DDAR_RW ? DMA_DEV_TO_MEM : DMA_MEM_TO_DEV)) {
dev_err(chan->device->dev, "vchan %p: bad DMA direction: DDAR:%08x dir:%u\n",
- c, c->ddar, dir);
+ &c->vc, c->ddar, dir);
return NULL;
}
@@ -612,14 +531,14 @@ static struct dma_async_tx_descriptor *sa11x0_dma_prep_slave_sg(
j += DIV_ROUND_UP(len, DMA_MAX_SIZE & ~DMA_ALIGN) - 1;
if (addr & DMA_ALIGN) {
dev_dbg(chan->device->dev, "vchan %p: bad buffer alignment: %08x\n",
- c, addr);
+ &c->vc, addr);
return NULL;
}
}
txd = kzalloc(sizeof(*txd) + j * sizeof(txd->sg[0]), GFP_ATOMIC);
if (!txd) {
- dev_dbg(chan->device->dev, "vchan %p: kzalloc failed\n", c);
+ dev_dbg(chan->device->dev, "vchan %p: kzalloc failed\n", &c->vc);
return NULL;
}
@@ -655,17 +574,14 @@ static struct dma_async_tx_descriptor *sa11x0_dma_prep_slave_sg(
} while (len);
}
- dma_async_tx_descriptor_init(&txd->tx, &c->chan);
- txd->tx.flags = flags;
- txd->tx.tx_submit = sa11x0_dma_tx_submit;
txd->ddar = c->ddar;
txd->size = size;
txd->sglen = j;
dev_dbg(chan->device->dev, "vchan %p: txd %p: size %u nr %u\n",
- c, txd, txd->size, txd->sglen);
+ &c->vc, &txd->vd, txd->size, txd->sglen);
- return &txd->tx;
+ return vchan_tx_prep(&c->vc, &txd->vd, flags);
}
static int sa11x0_dma_slave_config(struct sa11x0_dma_chan *c, struct dma_slave_config *cfg)
@@ -695,8 +611,8 @@ static int sa11x0_dma_slave_config(struct sa11x0_dma_chan *c, struct dma_slave_c
if (maxburst == 8)
ddar |= DDAR_BS;
- dev_dbg(c->chan.device->dev, "vchan %p: dma_slave_config addr %x width %u burst %u\n",
- c, addr, width, maxburst);
+ dev_dbg(c->vc.chan.device->dev, "vchan %p: dma_slave_config addr %x width %u burst %u\n",
+ &c->vc, addr, width, maxburst);
c->ddar = ddar | (addr & 0xf0000000) | (addr & 0x003ffffc) << 6;
@@ -718,16 +634,13 @@ static int sa11x0_dma_control(struct dma_chan *chan, enum dma_ctrl_cmd cmd,
return sa11x0_dma_slave_config(c, (struct dma_slave_config *)arg);
case DMA_TERMINATE_ALL:
- dev_dbg(d->slave.dev, "vchan %p: terminate all\n", c);
+ dev_dbg(d->slave.dev, "vchan %p: terminate all\n", &c->vc);
/* Clear the tx descriptor lists */
- spin_lock_irqsave(&c->lock, flags);
- list_splice_tail_init(&c->desc_submitted, &head);
- list_splice_tail_init(&c->desc_issued, &head);
+ spin_lock_irqsave(&c->vc.lock, flags);
+ vchan_get_all_descriptors(&c->vc, &head);
p = c->phy;
if (p) {
- struct sa11x0_dma_desc *txd, *txn;
-
dev_dbg(d->slave.dev, "pchan %u: terminating\n", p->num);
/* vchan is assigned to a pchan - stop the channel */
writel(DCSR_RUN | DCSR_IE |
@@ -735,17 +648,13 @@ static int sa11x0_dma_control(struct dma_chan *chan, enum dma_ctrl_cmd cmd,
DCSR_STRTB | DCSR_DONEB,
p->base + DMA_DCSR_C);
- list_for_each_entry_safe(txd, txn, &d->desc_complete, node)
- if (txd->tx.chan == &c->chan)
- list_move(&txd->node, &head);
-
if (p->txd_load) {
if (p->txd_load != p->txd_done)
- list_add_tail(&p->txd_load->node, &head);
+ list_add_tail(&p->txd_load->vd.node, &head);
p->txd_load = NULL;
}
if (p->txd_done) {
- list_add_tail(&p->txd_done->node, &head);
+ list_add_tail(&p->txd_done->vd.node, &head);
p->txd_done = NULL;
}
c->phy = NULL;
@@ -754,14 +663,14 @@ static int sa11x0_dma_control(struct dma_chan *chan, enum dma_ctrl_cmd cmd,
spin_unlock(&d->lock);
tasklet_schedule(&d->task);
}
- spin_unlock_irqrestore(&c->lock, flags);
- sa11x0_dma_desc_free(d, &head);
+ spin_unlock_irqrestore(&c->vc.lock, flags);
+ vchan_dma_desc_free_list(&c->vc, &head);
ret = 0;
break;
case DMA_PAUSE:
- dev_dbg(d->slave.dev, "vchan %p: pause\n", c);
- spin_lock_irqsave(&c->lock, flags);
+ dev_dbg(d->slave.dev, "vchan %p: pause\n", &c->vc);
+ spin_lock_irqsave(&c->vc.lock, flags);
if (c->status == DMA_IN_PROGRESS) {
c->status = DMA_PAUSED;
@@ -774,26 +683,26 @@ static int sa11x0_dma_control(struct dma_chan *chan, enum dma_ctrl_cmd cmd,
spin_unlock(&d->lock);
}
}
- spin_unlock_irqrestore(&c->lock, flags);
+ spin_unlock_irqrestore(&c->vc.lock, flags);
ret = 0;
break;
case DMA_RESUME:
- dev_dbg(d->slave.dev, "vchan %p: resume\n", c);
- spin_lock_irqsave(&c->lock, flags);
+ dev_dbg(d->slave.dev, "vchan %p: resume\n", &c->vc);
+ spin_lock_irqsave(&c->vc.lock, flags);
if (c->status == DMA_PAUSED) {
c->status = DMA_IN_PROGRESS;
p = c->phy;
if (p) {
writel(DCSR_RUN | DCSR_IE, p->base + DMA_DCSR_S);
- } else if (!list_empty(&c->desc_issued)) {
+ } else if (!list_empty(&c->vc.desc_issued)) {
spin_lock(&d->lock);
list_add_tail(&c->node, &d->chan_pending);
spin_unlock(&d->lock);
}
}
- spin_unlock_irqrestore(&c->lock, flags);
+ spin_unlock_irqrestore(&c->vc.lock, flags);
ret = 0;
break;
@@ -853,15 +762,13 @@ static int __devinit sa11x0_dma_init_dmadev(struct dma_device *dmadev,
return -ENOMEM;
}
- c->chan.device = dmadev;
c->status = DMA_IN_PROGRESS;
c->ddar = chan_desc[i].ddar;
c->name = chan_desc[i].name;
- spin_lock_init(&c->lock);
- INIT_LIST_HEAD(&c->desc_submitted);
- INIT_LIST_HEAD(&c->desc_issued);
INIT_LIST_HEAD(&c->node);
- list_add_tail(&c->chan.device_node, &dmadev->channels);
+
+ c->vc.desc_free = sa11x0_dma_free_desc;
+ vchan_init(&c->vc, dmadev);
}
return dma_async_device_register(dmadev);
@@ -890,8 +797,9 @@ static void sa11x0_dma_free_channels(struct dma_device *dmadev)
{
struct sa11x0_dma_chan *c, *cn;
- list_for_each_entry_safe(c, cn, &dmadev->channels, chan.device_node) {
- list_del(&c->chan.device_node);
+ list_for_each_entry_safe(c, cn, &dmadev->channels, vc.chan.device_node) {
+ list_del(&c->vc.chan.device_node);
+ tasklet_kill(&c->vc.task);
kfree(c);
}
}
@@ -915,7 +823,6 @@ static int __devinit sa11x0_dma_probe(struct platform_device *pdev)
spin_lock_init(&d->lock);
INIT_LIST_HEAD(&d->chan_pending);
- INIT_LIST_HEAD(&d->desc_complete);
d->base = ioremap(res->start, resource_size(res));
if (!d->base) {
diff --git a/drivers/dma/virt-dma.c b/drivers/dma/virt-dma.c
new file mode 100644
index 0000000..bd85b05
--- /dev/null
+++ b/drivers/dma/virt-dma.c
@@ -0,0 +1,99 @@
+/*
+ * Virtual DMA channel support for DMAengine
+ *
+ * Copyright (C) 2012 Russell King
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+#include <linux/device.h>
+#include <linux/dmaengine.h>
+#include <linux/module.h>
+#include <linux/spinlock.h>
+
+#include "virt-dma.h"
+
+static struct virt_dma_desc *to_virt_desc(struct dma_async_tx_descriptor *tx)
+{
+ return container_of(tx, struct virt_dma_desc, tx);
+}
+
+dma_cookie_t vchan_tx_submit(struct dma_async_tx_descriptor *tx)
+{
+ struct virt_dma_chan *vc = to_virt_chan(tx->chan);
+ struct virt_dma_desc *vd = to_virt_desc(tx);
+ unsigned long flags;
+ dma_cookie_t cookie;
+
+ spin_lock_irqsave(&vc->lock, flags);
+ cookie = dma_cookie_assign(tx);
+
+ list_add_tail(&vd->node, &vc->desc_submitted);
+ spin_unlock_irqrestore(&vc->lock, flags);
+
+ dev_dbg(vc->chan.device->dev, "vchan %p: txd %p[%x]: submitted\n",
+ vc, vd, cookie);
+
+ return cookie;
+}
+EXPORT_SYMBOL_GPL(vchan_tx_submit);
+
+/*
+ * This tasklet handles the completion of a DMA descriptor by
+ * calling its callback and freeing it.
+ */
+static void vchan_complete(unsigned long arg)
+{
+ struct virt_dma_chan *vc = (struct virt_dma_chan *)arg;
+ LIST_HEAD(head);
+
+ spin_lock_irq(&vc->lock);
+ list_splice_tail_init(&vc->desc_completed, &head);
+ spin_unlock_irq(&vc->lock);
+
+ while (!list_empty(&head)) {
+ struct virt_dma_desc *vd = list_first_entry(&head,
+ struct virt_dma_desc, node);
+ dma_async_tx_callback cb = vd->tx.callback;
+ void *cb_data = vd->tx.callback_param;
+
+ list_del(&vd->node);
+
+ vc->desc_free(vd);
+
+ if (cb)
+ cb(cb_data);
+ }
+}
+
+void vchan_dma_desc_free_list(struct virt_dma_chan *vc, struct list_head *head)
+{
+ while (!list_empty(head)) {
+ struct virt_dma_desc *vd = list_first_entry(head,
+ struct virt_dma_desc, node);
+ list_del(&vd->node);
+ dev_dbg(vc->chan.device->dev, "txd %p: freeing\n", vd);
+ vc->desc_free(vd);
+ }
+}
+EXPORT_SYMBOL_GPL(vchan_dma_desc_free_list);
+
+void vchan_init(struct virt_dma_chan *vc, struct dma_device *dmadev)
+{
+ dma_cookie_init(&vc->chan);
+
+ spin_lock_init(&vc->lock);
+ INIT_LIST_HEAD(&vc->desc_submitted);
+ INIT_LIST_HEAD(&vc->desc_issued);
+ INIT_LIST_HEAD(&vc->desc_completed);
+
+ tasklet_init(&vc->task, vchan_complete, (unsigned long)vc);
+
+ vc->chan.device = dmadev;
+ list_add_tail(&vc->chan.device_node, &dmadev->channels);
+}
+EXPORT_SYMBOL_GPL(vchan_init);
+
+MODULE_AUTHOR("Russell King");
+MODULE_LICENSE("GPL");
diff --git a/drivers/dma/virt-dma.h b/drivers/dma/virt-dma.h
new file mode 100644
index 0000000..825bb96
--- /dev/null
+++ b/drivers/dma/virt-dma.h
@@ -0,0 +1,138 @@
+/*
+ * Virtual DMA channel support for DMAengine
+ *
+ * Copyright (C) 2012 Russell King
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+#ifndef VIRT_DMA_H
+#define VIRT_DMA_H
+
+#include <linux/dmaengine.h>
+#include <linux/interrupt.h>
+
+#include "dmaengine.h"
+
+struct virt_dma_desc {
+ struct dma_async_tx_descriptor tx;
+ /* protected by vc.lock */
+ struct list_head node;
+};
+
+struct virt_dma_chan {
+ struct dma_chan chan;
+ struct tasklet_struct task;
+ void (*desc_free)(struct virt_dma_desc *);
+
+ spinlock_t lock;
+
+ /* protected by vc.lock */
+ struct list_head desc_submitted;
+ struct list_head desc_issued;
+ struct list_head desc_completed;
+};
+
+static inline struct virt_dma_chan *to_virt_chan(struct dma_chan *chan)
+{
+ return container_of(chan, struct virt_dma_chan, chan);
+}
+
+void vchan_dma_desc_free_list(struct virt_dma_chan *vc, struct list_head *head);
+
+void vchan_init(struct virt_dma_chan *vc, struct dma_device *dmadev);
+
+/**
+ * vchan_tx_prep - prepare a descriptor
+ * vc: virtual channel allocating this descriptor
+ * vd: virtual descriptor to prepare
+ * tx_flags: flags argument passed in to prepare function
+ */
+static inline struct dma_async_tx_descriptor *vchan_tx_prep(struct virt_dma_chan *vc,
+ struct virt_dma_desc *vd, unsigned long tx_flags)
+{
+ extern dma_cookie_t vchan_tx_submit(struct dma_async_tx_descriptor *);
+
+ dma_async_tx_descriptor_init(&vd->tx, &vc->chan);
+ vd->tx.flags = tx_flags;
+ vd->tx.tx_submit = vchan_tx_submit;
+
+ return &vd->tx;
+}
+
+/**
+ * vchan_issue_pending - move submitted descriptors to issued list
+ * vc: virtual channel to update
+ *
+ * vc.lock must be held by caller
+ */
+static inline bool vchan_issue_pending(struct virt_dma_chan *vc)
+{
+ list_splice_tail_init(&vc->desc_submitted, &vc->desc_issued);
+ return !list_empty(&vc->desc_issued);
+}
+
+/**
+ * vchan_cookie_complete - report completion of a descriptor
+ * vd: virtual descriptor to update
+ *
+ * vc.lock must be held by caller
+ */
+static inline void vchan_cookie_complete(struct virt_dma_desc *vd)
+{
+ struct virt_dma_chan *vc = to_virt_chan(vd->tx.chan);
+
+ dma_cookie_complete(&vd->tx);
+ dev_vdbg(vc->chan.device->dev, "txd %p[%x]: marked complete\n",
+ vd, vd->tx.cookie);
+ list_add_tail(&vd->node, &vc->desc_completed);
+
+ tasklet_schedule(&vc->task);
+}
+
+/**
+ * vchan_next_desc - peek at the next descriptor to be processed
+ * vc: virtual channel to obtain descriptor from
+ *
+ * vc.lock must be held by caller
+ */
+static inline struct virt_dma_desc *vchan_next_desc(struct virt_dma_chan *vc)
+{
+ if (list_empty(&vc->desc_issued))
+ return NULL;
+
+ return list_first_entry(&vc->desc_issued, struct virt_dma_desc, node);
+}
+
+/**
+ * vchan_get_all_descriptors - obtain all submitted and issued descriptors
+ * vc: virtual channel to get descriptors from
+ * head: list of descriptors found
+ *
+ * vc.lock must be held by caller
+ *
+ * Removes all submitted and issued descriptors from internal lists, and
+ * provides a list of all descriptors found
+ */
+static inline void vchan_get_all_descriptors(struct virt_dma_chan *vc,
+ struct list_head *head)
+{
+ list_splice_tail_init(&vc->desc_submitted, head);
+ list_splice_tail_init(&vc->desc_issued, head);
+ list_splice_tail_init(&vc->desc_completed, head);
+}
+
+static inline void vchan_free_chan_resources(struct virt_dma_chan *vc)
+{
+ unsigned long flags;
+ LIST_HEAD(head);
+
+ spin_lock_irqsave(&vc->lock, flags);
+ vchan_get_all_descriptors(vc, &head);
+ spin_unlock_irqrestore(&vc->lock, flags);
+
+ vchan_dma_desc_free_list(vc, &head);
+}
+
+#endif
--
1.7.4.4
--
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