* [PATCH 1/2] Fix a bug about BUG_ON() on DMA engine capability DMA_INTERRUPT.
@ 2008-03-11 3:25 Zhang Wei
2008-03-11 3:25 ` [PATCH 2/2] Add device_prep_dma_interrupt support to fsldma.c Zhang Wei
0 siblings, 1 reply; 5+ messages in thread
From: Zhang Wei @ 2008-03-11 3:25 UTC (permalink / raw
To: dan.j.williams; +Cc: linux-kernel, Zhang Wei
The device->device_prep_dma_interrupt function is used by
DMA_INTERRUPT capability, not DMA_ZERO_SUM.
Signed-off-by: Zhang Wei <wei.zhang@freescale.com>
---
drivers/dma/dmaengine.c | 2 +-
1 files changed, 1 insertions(+), 1 deletions(-)
diff --git a/drivers/dma/dmaengine.c b/drivers/dma/dmaengine.c
index 2996523..8db0e7f 100644
--- a/drivers/dma/dmaengine.c
+++ b/drivers/dma/dmaengine.c
@@ -357,7 +357,7 @@ int dma_async_device_register(struct dma_device *device)
!device->device_prep_dma_zero_sum);
BUG_ON(dma_has_cap(DMA_MEMSET, device->cap_mask) &&
!device->device_prep_dma_memset);
- BUG_ON(dma_has_cap(DMA_ZERO_SUM, device->cap_mask) &&
+ BUG_ON(dma_has_cap(DMA_INTERRUPT, device->cap_mask) &&
!device->device_prep_dma_interrupt);
BUG_ON(!device->device_alloc_chan_resources);
--
1.5.4
^ permalink raw reply related [flat|nested] 5+ messages in thread
* [PATCH 2/2] Add device_prep_dma_interrupt support to fsldma.c
2008-03-11 3:25 [PATCH 1/2] Fix a bug about BUG_ON() on DMA engine capability DMA_INTERRUPT Zhang Wei
@ 2008-03-11 3:25 ` Zhang Wei
2008-03-11 21:55 ` Dan Williams
0 siblings, 1 reply; 5+ messages in thread
From: Zhang Wei @ 2008-03-11 3:25 UTC (permalink / raw
To: dan.j.williams; +Cc: linux-kernel, Zhang Wei
This is a bug that I assigned DMA_INTERRUPT capability to fsldma
but missing device_prep_dma_interrupt function. For a bug in
dmaengine.c the driver passed BUG_ON() checking. The patch fixes it.
Signed-off-by: Zhang Wei <wei.zhang@freescale.com>
---
drivers/dma/fsldma.c | 27 +++++++++++++++++++++++++++
1 files changed, 27 insertions(+), 0 deletions(-)
diff --git a/drivers/dma/fsldma.c b/drivers/dma/fsldma.c
index 5dfedf3..5428f81 100644
--- a/drivers/dma/fsldma.c
+++ b/drivers/dma/fsldma.c
@@ -406,6 +406,32 @@ static void fsl_dma_free_chan_resources(struct dma_chan *chan)
dma_pool_destroy(fsl_chan->desc_pool);
}
+static struct dma_async_tx_descriptor *fsl_dma_prep_interrupt(
+ struct dma_chan *chan)
+{
+ struct fsl_dma_chan *fsl_chan;
+ struct fsl_desc_sw *new;
+
+ if (!chan)
+ return NULL;
+
+ fsl_chan = to_fsl_chan(chan);
+
+ new = fsl_dma_alloc_descriptor(fsl_chan);
+ if (!new) {
+ dev_err(fsl_chan->dev, "No free memory for link descriptor\n");
+ return NULL;
+ }
+
+ new->async_tx.cookie = -EBUSY;
+ new->async_tx.ack = 0;
+
+ /* Set End-of-link to the last link descriptor of new list*/
+ set_ld_eol(fsl_chan, new);
+
+ return &new->async_tx;
+}
+
static struct dma_async_tx_descriptor *fsl_dma_prep_memcpy(
struct dma_chan *chan, dma_addr_t dma_dest, dma_addr_t dma_src,
size_t len, unsigned long flags)
@@ -1020,6 +1046,7 @@ static int __devinit of_fsl_dma_probe(struct of_device *dev,
dma_cap_set(DMA_INTERRUPT, fdev->common.cap_mask);
fdev->common.device_alloc_chan_resources = fsl_dma_alloc_chan_resources;
fdev->common.device_free_chan_resources = fsl_dma_free_chan_resources;
+ fdev->common.device_prep_dma_interrupt = fsl_dma_prep_interrupt;
fdev->common.device_prep_dma_memcpy = fsl_dma_prep_memcpy;
fdev->common.device_is_tx_complete = fsl_dma_is_complete;
fdev->common.device_issue_pending = fsl_dma_memcpy_issue_pending;
--
1.5.4
^ permalink raw reply related [flat|nested] 5+ messages in thread
* Re: [PATCH 2/2] Add device_prep_dma_interrupt support to fsldma.c
2008-03-11 3:25 ` [PATCH 2/2] Add device_prep_dma_interrupt support to fsldma.c Zhang Wei
@ 2008-03-11 21:55 ` Dan Williams
2008-03-12 2:28 ` Zhang Wei
0 siblings, 1 reply; 5+ messages in thread
From: Dan Williams @ 2008-03-11 21:55 UTC (permalink / raw
To: Zhang Wei; +Cc: linux-kernel
On Mon, Mar 10, 2008 at 8:25 PM, Zhang Wei <wei.zhang@freescale.com> wrote:
> This is a bug that I assigned DMA_INTERRUPT capability to fsldma
> but missing device_prep_dma_interrupt function. For a bug in
> dmaengine.c the driver passed BUG_ON() checking. The patch fixes it.
>
> Signed-off-by: Zhang Wei <wei.zhang@freescale.com>
> ---
> drivers/dma/fsldma.c | 27 +++++++++++++++++++++++++++
> 1 files changed, 27 insertions(+), 0 deletions(-)
>
> diff --git a/drivers/dma/fsldma.c b/drivers/dma/fsldma.c
> index 5dfedf3..5428f81 100644
> --- a/drivers/dma/fsldma.c
> +++ b/drivers/dma/fsldma.c
> @@ -406,6 +406,32 @@ static void fsl_dma_free_chan_resources(struct dma_chan *chan)
> dma_pool_destroy(fsl_chan->desc_pool);
> }
>
> +static struct dma_async_tx_descriptor *fsl_dma_prep_interrupt(
> + struct dma_chan *chan)
> +{
> + struct fsl_dma_chan *fsl_chan;
> + struct fsl_desc_sw *new;
> +
> + if (!chan)
> + return NULL;
> +
> + fsl_chan = to_fsl_chan(chan);
> +
> + new = fsl_dma_alloc_descriptor(fsl_chan);
> + if (!new) {
> + dev_err(fsl_chan->dev, "No free memory for link descriptor\n");
> + return NULL;
> + }
> +
> + new->async_tx.cookie = -EBUSY;
> + new->async_tx.ack = 0;
> +
> + /* Set End-of-link to the last link descriptor of new list*/
> + set_ld_eol(fsl_chan, new);
Question, is 'set_ld_eol' safe to call on descriptors that may not be
the last in the list? For example what about the following sequence:
/* prepare two descriptors */
tx1 = fsl_dma_prep_interrupt(chan);
tx2 = fsl_dma_prep_memcpy(chan);
/* submit out of order */
tx2->tx_submit(tx2);
tx1->tx_submit(tx1);
This is only a concern if you plan to support channel switching at
some point. For example, switching from a memcpy channel to an xor
channel.
Thanks,
Dan
^ permalink raw reply [flat|nested] 5+ messages in thread
* RE: [PATCH 2/2] Add device_prep_dma_interrupt support to fsldma.c
2008-03-11 21:55 ` Dan Williams
@ 2008-03-12 2:28 ` Zhang Wei
2008-03-12 16:38 ` Dan Williams
0 siblings, 1 reply; 5+ messages in thread
From: Zhang Wei @ 2008-03-12 2:28 UTC (permalink / raw
To: Dan Williams; +Cc: linux-kernel
Hi, Dan,
> -----Original Message-----
> From: dan.j.williams@gmail.com
> > +
> > + /* Set End-of-link to the last link descriptor of
> new list*/
> > + set_ld_eol(fsl_chan, new);
>
> Question, is 'set_ld_eol' safe to call on descriptors that may not be
> the last in the list? For example what about the following sequence:
set_ld_eol() is a safe function, which is only for preparing the tx descriptors
lists. When adding prepared tx descriptior list to DMA channel tx list,
the function append_ld_queue() should be called.
>
> /* prepare two descriptors */
> tx1 = fsl_dma_prep_interrupt(chan);
> tx2 = fsl_dma_prep_memcpy(chan);
>
> /* submit out of order */
> tx2->tx_submit(tx2);
> tx1->tx_submit(tx1);
>
> This is only a concern if you plan to support channel switching at
> some point. For example, switching from a memcpy channel to an xor
> channel.
>
It's no problem. :) In fact, I've added out of order testing codes in fsl_dma_self_test()
function.
But I have a question about device_prep_dma_interrupt(), which is no way to assign
dest and src address. Is it a null tx action dma_async_tx_descriptor except to trigger
an interrupt?
Thanks!
Wei.
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH 2/2] Add device_prep_dma_interrupt support to fsldma.c
2008-03-12 2:28 ` Zhang Wei
@ 2008-03-12 16:38 ` Dan Williams
0 siblings, 0 replies; 5+ messages in thread
From: Dan Williams @ 2008-03-12 16:38 UTC (permalink / raw
To: Zhang Wei; +Cc: linux-kernel
On Tue, Mar 11, 2008 at 7:28 PM, Zhang Wei <Wei.Zhang@freescale.com> wrote:
[..]
> But I have a question about device_prep_dma_interrupt(), which is no way to assign
> dest and src address. Is it a null tx action dma_async_tx_descriptor except to trigger
> an interrupt?
>
Yes, it is for sequences where we are scheduling a chain of operations
of indeterminate length and want a callback after they all complete.
See ops_run_biofill() in drivers/md/raid5.c for an example.
> Thanks!
> Wei.
--
Dan
^ permalink raw reply [flat|nested] 5+ messages in thread
end of thread, other threads:[~2008-03-12 16:38 UTC | newest]
Thread overview: 5+ messages (download: mbox.gz follow: Atom feed
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2008-03-11 3:25 [PATCH 1/2] Fix a bug about BUG_ON() on DMA engine capability DMA_INTERRUPT Zhang Wei
2008-03-11 3:25 ` [PATCH 2/2] Add device_prep_dma_interrupt support to fsldma.c Zhang Wei
2008-03-11 21:55 ` Dan Williams
2008-03-12 2:28 ` Zhang Wei
2008-03-12 16:38 ` Dan Williams
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