* [PATCH 1/2] dma: of: Add generic xlate function for matching by channel id
@ 2013-03-25 13:16 Lars-Peter Clausen
2013-03-25 13:16 ` [PATCH 2/2] dma: pl330: Use the generic of_dma_xlate_by_chan_id Lars-Peter Clausen
2013-03-29 21:49 ` [PATCH 1/2] dma: of: Add generic xlate function for matching by channel id Vinod Koul
0 siblings, 2 replies; 7+ messages in thread
From: Lars-Peter Clausen @ 2013-03-25 13:16 UTC (permalink / raw)
To: Vinod Koul, Dan Williams
Cc: Jon Hunter, Padmavathi Venna, linux-kernel, Lars-Peter Clausen
This patch adds a new generic of dma xlate callback function which will match a
channel by its id.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
---
drivers/dma/of-dma.c | 47 +++++++++++++++++++++++++++++++++++++++++++++++
include/linux/of_dma.h | 4 ++++
2 files changed, 51 insertions(+)
diff --git a/drivers/dma/of-dma.c b/drivers/dma/of-dma.c
index 00db454..7cad4d7 100644
--- a/drivers/dma/of-dma.c
+++ b/drivers/dma/of-dma.c
@@ -269,3 +269,50 @@ struct dma_chan *of_dma_simple_xlate(struct of_phandle_args *dma_spec,
&dma_spec->args[0]);
}
EXPORT_SYMBOL_GPL(of_dma_simple_xlate);
+
+struct of_dma_filter_by_chan_id_args {
+ struct dma_device *dev;
+ unsigned int chan_id;
+};
+
+static bool of_dma_filter_by_chan_id(struct dma_chan *chan, void *params)
+{
+ struct of_dma_filter_by_chan_id_args *args = params;
+
+ return chan->device == args->dev && chan->chan_id == args->chan_id;
+}
+
+/**
+ * of_dma_xlate_by_chan_id - Translate dt property to DMA channel by channel id
+ * @dma_spec: pointer to DMA specifier as found in the device tree
+ * @of_dma: pointer to DMA controller data
+ *
+ * This function can be used as the of xlate callback for DMA driver which want
+ * to match the channel based on the channel id. When using this xlate function
+ * the #dma-cells propety of the DMA controller dt node needs to be set to 1.
+ * The data parameter of of_dma_controller_register must be a pointer to the
+ * dma_device struct the function should match uppon.
+ *
+ * Returns pointer to appropriate dma channel on success or NULL on error.
+ */
+struct dma_chan *of_dma_xlate_by_chan_id(struct of_phandle_args *dma_spec,
+ struct of_dma *ofdma)
+{
+ struct of_dma_filter_by_chan_id_args args;
+ dma_cap_mask_t cap;
+
+ args.dev = ofdma->of_dma_data;
+ if (!args.dev)
+ return NULL;
+
+ if (dma_spec->args_count != 1)
+ return NULL;
+
+ dma_cap_zero(cap);
+ dma_cap_set(DMA_SLAVE, cap);
+
+ args.chan_id = dma_spec->args[0];
+
+ return dma_request_channel(cap, of_dma_filter_by_chan_id, &args);
+}
+EXPORT_SYMBOL_GPL(of_dma_xlate_by_chan_id);
diff --git a/include/linux/of_dma.h b/include/linux/of_dma.h
index ce6a8ab..46732d3 100644
--- a/include/linux/of_dma.h
+++ b/include/linux/of_dma.h
@@ -43,6 +43,8 @@ extern struct dma_chan *of_dma_request_slave_channel(struct device_node *np,
const char *name);
extern struct dma_chan *of_dma_simple_xlate(struct of_phandle_args *dma_spec,
struct of_dma *ofdma);
+extern struct dma_chan *of_dma_xlate_by_chan_id(struct of_phandle_args *dma_spec,
+ struct of_dma *ofdma);
#else
static inline int of_dma_controller_register(struct device_node *np,
struct dma_chan *(*of_dma_xlate)
@@ -69,6 +71,8 @@ static inline struct dma_chan *of_dma_simple_xlate(struct of_phandle_args *dma_s
return NULL;
}
+#define of_dma_xlate_by_chan_id NULL
+
#endif
#endif /* __LINUX_OF_DMA_H */
--
1.8.0
^ permalink raw reply related [flat|nested] 7+ messages in thread
* [PATCH 2/2] dma: pl330: Use the generic of_dma_xlate_by_chan_id
2013-03-25 13:16 [PATCH 1/2] dma: of: Add generic xlate function for matching by channel id Lars-Peter Clausen
@ 2013-03-25 13:16 ` Lars-Peter Clausen
2013-03-29 21:49 ` [PATCH 1/2] dma: of: Add generic xlate function for matching by channel id Vinod Koul
1 sibling, 0 replies; 7+ messages in thread
From: Lars-Peter Clausen @ 2013-03-25 13:16 UTC (permalink / raw)
To: Vinod Koul, Dan Williams
Cc: Jon Hunter, Padmavathi Venna, linux-kernel, Lars-Peter Clausen
Use the generic of_dma_xlate_by_chan_id xlate callback instead of a custom
implementation.
There is one minor difference between the generic of_dma_xlate_by_chan_id
function and the pl330 specific one. of_dma_xlate_by_chan_id only sets the
DMA_SLAVE capability for the channel capability mask, while the pl330 driver
additionally sets the DMA_CYCLIC capability. But since all pl330 channels which
have the DMA_SLAVE capability set also have DMA_CYCLIC capability set both
functions will have the same result.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
---
drivers/dma/pl330.c | 41 +----------------------------------------
1 file changed, 1 insertion(+), 40 deletions(-)
diff --git a/drivers/dma/pl330.c b/drivers/dma/pl330.c
index 345e2a1..ea48de7 100644
--- a/drivers/dma/pl330.c
+++ b/drivers/dma/pl330.c
@@ -608,11 +608,6 @@ struct dma_pl330_desc {
struct dma_pl330_chan *pchan;
};
-struct dma_pl330_filter_args {
- struct dma_pl330_dmac *pdmac;
- unsigned int chan_id;
-};
-
static inline void _callback(struct pl330_req *r, enum pl330_op_err err)
{
if (r && r->xfer_cb)
@@ -2358,16 +2353,6 @@ static void dma_pl330_rqcb(void *token, enum pl330_op_err err)
tasklet_schedule(&pch->task);
}
-static bool pl330_dt_filter(struct dma_chan *chan, void *param)
-{
- struct dma_pl330_filter_args *fargs = param;
-
- if (chan->device != &fargs->pdmac->ddma)
- return false;
-
- return (chan->chan_id == fargs->chan_id);
-}
-
bool pl330_filter(struct dma_chan *chan, void *param)
{
u8 *peri_id;
@@ -2380,30 +2365,6 @@ bool pl330_filter(struct dma_chan *chan, void *param)
}
EXPORT_SYMBOL(pl330_filter);
-static struct dma_chan *of_dma_pl330_xlate(struct of_phandle_args *dma_spec,
- struct of_dma *ofdma)
-{
- int count = dma_spec->args_count;
- struct dma_pl330_dmac *pdmac = ofdma->of_dma_data;
- struct dma_pl330_filter_args fargs;
- dma_cap_mask_t cap;
-
- if (!pdmac)
- return NULL;
-
- if (count != 1)
- return NULL;
-
- fargs.pdmac = pdmac;
- fargs.chan_id = dma_spec->args[0];
-
- dma_cap_zero(cap);
- dma_cap_set(DMA_SLAVE, cap);
- dma_cap_set(DMA_CYCLIC, cap);
-
- return dma_request_channel(cap, pl330_dt_filter, &fargs);
-}
-
static int pl330_alloc_chan_resources(struct dma_chan *chan)
{
struct dma_pl330_chan *pch = to_pchan(chan);
@@ -2996,7 +2957,7 @@ pl330_probe(struct amba_device *adev, const struct amba_id *id)
pi->pcfg.num_peri, pi->pcfg.num_events);
ret = of_dma_controller_register(adev->dev.of_node,
- of_dma_pl330_xlate, pdmac);
+ of_dma_xlate_by_chan_id, pd);
if (ret) {
dev_err(&adev->dev,
"unable to register DMA to the generic DT DMA helpers\n");
--
1.8.0
^ permalink raw reply related [flat|nested] 7+ messages in thread
* Re: [PATCH 1/2] dma: of: Add generic xlate function for matching by channel id
2013-03-25 13:16 [PATCH 1/2] dma: of: Add generic xlate function for matching by channel id Lars-Peter Clausen
2013-03-25 13:16 ` [PATCH 2/2] dma: pl330: Use the generic of_dma_xlate_by_chan_id Lars-Peter Clausen
@ 2013-03-29 21:49 ` Vinod Koul
2013-03-30 8:38 ` Lars-Peter Clausen
1 sibling, 1 reply; 7+ messages in thread
From: Vinod Koul @ 2013-03-29 21:49 UTC (permalink / raw)
To: Lars-Peter Clausen, Arnd Bergmann
Cc: Dan Williams, Jon Hunter, Padmavathi Venna, linux-kernel
On Mon, Mar 25, 2013 at 02:16:51PM +0100, Lars-Peter Clausen wrote:
> This patch adds a new generic of dma xlate callback function which will match a
> channel by its id.
how will the client know which "id" to request?
>
> Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
> ---
> drivers/dma/of-dma.c | 47 +++++++++++++++++++++++++++++++++++++++++++++++
> include/linux/of_dma.h | 4 ++++
> 2 files changed, 51 insertions(+)
>
> diff --git a/drivers/dma/of-dma.c b/drivers/dma/of-dma.c
> index 00db454..7cad4d7 100644
> --- a/drivers/dma/of-dma.c
> +++ b/drivers/dma/of-dma.c
> @@ -269,3 +269,50 @@ struct dma_chan *of_dma_simple_xlate(struct of_phandle_args *dma_spec,
> &dma_spec->args[0]);
> }
> EXPORT_SYMBOL_GPL(of_dma_simple_xlate);
> +
> +struct of_dma_filter_by_chan_id_args {
> + struct dma_device *dev;
> + unsigned int chan_id;
> +};
> +
> +static bool of_dma_filter_by_chan_id(struct dma_chan *chan, void *params)
> +{
> + struct of_dma_filter_by_chan_id_args *args = params;
> +
> + return chan->device == args->dev && chan->chan_id == args->chan_id;
> +}
> +
> +/**
> + * of_dma_xlate_by_chan_id - Translate dt property to DMA channel by channel id
> + * @dma_spec: pointer to DMA specifier as found in the device tree
> + * @of_dma: pointer to DMA controller data
> + *
> + * This function can be used as the of xlate callback for DMA driver which want
> + * to match the channel based on the channel id. When using this xlate function
> + * the #dma-cells propety of the DMA controller dt node needs to be set to 1.
> + * The data parameter of of_dma_controller_register must be a pointer to the
> + * dma_device struct the function should match uppon.
> + *
> + * Returns pointer to appropriate dma channel on success or NULL on error.
> + */
> +struct dma_chan *of_dma_xlate_by_chan_id(struct of_phandle_args *dma_spec,
> + struct of_dma *ofdma)
> +{
> + struct of_dma_filter_by_chan_id_args args;
> + dma_cap_mask_t cap;
> +
> + args.dev = ofdma->of_dma_data;
> + if (!args.dev)
> + return NULL;
> +
> + if (dma_spec->args_count != 1)
> + return NULL;
> +
> + dma_cap_zero(cap);
> + dma_cap_set(DMA_SLAVE, cap);
> +
> + args.chan_id = dma_spec->args[0];
> +
> + return dma_request_channel(cap, of_dma_filter_by_chan_id, &args);
> +}
> +EXPORT_SYMBOL_GPL(of_dma_xlate_by_chan_id);
> diff --git a/include/linux/of_dma.h b/include/linux/of_dma.h
> index ce6a8ab..46732d3 100644
> --- a/include/linux/of_dma.h
> +++ b/include/linux/of_dma.h
> @@ -43,6 +43,8 @@ extern struct dma_chan *of_dma_request_slave_channel(struct device_node *np,
> const char *name);
> extern struct dma_chan *of_dma_simple_xlate(struct of_phandle_args *dma_spec,
> struct of_dma *ofdma);
> +extern struct dma_chan *of_dma_xlate_by_chan_id(struct of_phandle_args *dma_spec,
> + struct of_dma *ofdma);
> #else
> static inline int of_dma_controller_register(struct device_node *np,
> struct dma_chan *(*of_dma_xlate)
> @@ -69,6 +71,8 @@ static inline struct dma_chan *of_dma_simple_xlate(struct of_phandle_args *dma_s
> return NULL;
> }
>
> +#define of_dma_xlate_by_chan_id NULL
> +
> #endif
>
> #endif /* __LINUX_OF_DMA_H */
> --
> 1.8.0
>
^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [PATCH 1/2] dma: of: Add generic xlate function for matching by channel id
2013-03-29 21:49 ` [PATCH 1/2] dma: of: Add generic xlate function for matching by channel id Vinod Koul
@ 2013-03-30 8:38 ` Lars-Peter Clausen
2013-04-09 11:28 ` Vinod Koul
0 siblings, 1 reply; 7+ messages in thread
From: Lars-Peter Clausen @ 2013-03-30 8:38 UTC (permalink / raw)
To: Vinod Koul
Cc: Arnd Bergmann, Dan Williams, Jon Hunter, Padmavathi Venna, linux-kernel
On 03/29/2013 10:49 PM, Vinod Koul wrote:
> On Mon, Mar 25, 2013 at 02:16:51PM +0100, Lars-Peter Clausen wrote:
>> This patch adds a new generic of dma xlate callback function which will match a
>> channel by its id.
> how will the client know which "id" to request?
The devicetree tells it, or what exactly do you mean?
- Lars
>
>>
>> Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
>> ---
>> drivers/dma/of-dma.c | 47 +++++++++++++++++++++++++++++++++++++++++++++++
>> include/linux/of_dma.h | 4 ++++
>> 2 files changed, 51 insertions(+)
>>
>> diff --git a/drivers/dma/of-dma.c b/drivers/dma/of-dma.c
>> index 00db454..7cad4d7 100644
>> --- a/drivers/dma/of-dma.c
>> +++ b/drivers/dma/of-dma.c
>> @@ -269,3 +269,50 @@ struct dma_chan *of_dma_simple_xlate(struct of_phandle_args *dma_spec,
>> &dma_spec->args[0]);
>> }
>> EXPORT_SYMBOL_GPL(of_dma_simple_xlate);
>> +
>> +struct of_dma_filter_by_chan_id_args {
>> + struct dma_device *dev;
>> + unsigned int chan_id;
>> +};
>> +
>> +static bool of_dma_filter_by_chan_id(struct dma_chan *chan, void *params)
>> +{
>> + struct of_dma_filter_by_chan_id_args *args = params;
>> +
>> + return chan->device == args->dev && chan->chan_id == args->chan_id;
>> +}
>> +
>> +/**
>> + * of_dma_xlate_by_chan_id - Translate dt property to DMA channel by channel id
>> + * @dma_spec: pointer to DMA specifier as found in the device tree
>> + * @of_dma: pointer to DMA controller data
>> + *
>> + * This function can be used as the of xlate callback for DMA driver which want
>> + * to match the channel based on the channel id. When using this xlate function
>> + * the #dma-cells propety of the DMA controller dt node needs to be set to 1.
>> + * The data parameter of of_dma_controller_register must be a pointer to the
>> + * dma_device struct the function should match uppon.
>> + *
>> + * Returns pointer to appropriate dma channel on success or NULL on error.
>> + */
>> +struct dma_chan *of_dma_xlate_by_chan_id(struct of_phandle_args *dma_spec,
>> + struct of_dma *ofdma)
>> +{
>> + struct of_dma_filter_by_chan_id_args args;
>> + dma_cap_mask_t cap;
>> +
>> + args.dev = ofdma->of_dma_data;
>> + if (!args.dev)
>> + return NULL;
>> +
>> + if (dma_spec->args_count != 1)
>> + return NULL;
>> +
>> + dma_cap_zero(cap);
>> + dma_cap_set(DMA_SLAVE, cap);
>> +
>> + args.chan_id = dma_spec->args[0];
>> +
>> + return dma_request_channel(cap, of_dma_filter_by_chan_id, &args);
>> +}
>> +EXPORT_SYMBOL_GPL(of_dma_xlate_by_chan_id);
>> diff --git a/include/linux/of_dma.h b/include/linux/of_dma.h
>> index ce6a8ab..46732d3 100644
>> --- a/include/linux/of_dma.h
>> +++ b/include/linux/of_dma.h
>> @@ -43,6 +43,8 @@ extern struct dma_chan *of_dma_request_slave_channel(struct device_node *np,
>> const char *name);
>> extern struct dma_chan *of_dma_simple_xlate(struct of_phandle_args *dma_spec,
>> struct of_dma *ofdma);
>> +extern struct dma_chan *of_dma_xlate_by_chan_id(struct of_phandle_args *dma_spec,
>> + struct of_dma *ofdma);
>> #else
>> static inline int of_dma_controller_register(struct device_node *np,
>> struct dma_chan *(*of_dma_xlate)
>> @@ -69,6 +71,8 @@ static inline struct dma_chan *of_dma_simple_xlate(struct of_phandle_args *dma_s
>> return NULL;
>> }
>>
>> +#define of_dma_xlate_by_chan_id NULL
>> +
>> #endif
>>
>> #endif /* __LINUX_OF_DMA_H */
>> --
>> 1.8.0
>>
^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [PATCH 1/2] dma: of: Add generic xlate function for matching by channel id
2013-03-30 8:38 ` Lars-Peter Clausen
@ 2013-04-09 11:28 ` Vinod Koul
2013-04-09 12:36 ` Lars-Peter Clausen
0 siblings, 1 reply; 7+ messages in thread
From: Vinod Koul @ 2013-04-09 11:28 UTC (permalink / raw)
To: Lars-Peter Clausen, Arnd Bergmann
Cc: Arnd Bergmann, Dan Williams, Jon Hunter, Padmavathi Venna, linux-kernel
On Sat, Mar 30, 2013 at 09:38:54AM +0100, Lars-Peter Clausen wrote:
> On 03/29/2013 10:49 PM, Vinod Koul wrote:
> > On Mon, Mar 25, 2013 at 02:16:51PM +0100, Lars-Peter Clausen wrote:
> >> This patch adds a new generic of dma xlate callback function which will match a
> >> channel by its id.
> > how will the client know which "id" to request?
>
> The devicetree tells it, or what exactly do you mean?
Is this global id? Anrd, what does the id mean in DT?
>
> - Lars
>
> >
> >>
> >> Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
> >> ---
> >> drivers/dma/of-dma.c | 47 +++++++++++++++++++++++++++++++++++++++++++++++
> >> include/linux/of_dma.h | 4 ++++
> >> 2 files changed, 51 insertions(+)
> >>
> >> diff --git a/drivers/dma/of-dma.c b/drivers/dma/of-dma.c
> >> index 00db454..7cad4d7 100644
> >> --- a/drivers/dma/of-dma.c
> >> +++ b/drivers/dma/of-dma.c
> >> @@ -269,3 +269,50 @@ struct dma_chan *of_dma_simple_xlate(struct of_phandle_args *dma_spec,
> >> &dma_spec->args[0]);
> >> }
> >> EXPORT_SYMBOL_GPL(of_dma_simple_xlate);
> >> +
> >> +struct of_dma_filter_by_chan_id_args {
> >> + struct dma_device *dev;
> >> + unsigned int chan_id;
> >> +};
> >> +
> >> +static bool of_dma_filter_by_chan_id(struct dma_chan *chan, void *params)
> >> +{
> >> + struct of_dma_filter_by_chan_id_args *args = params;
> >> +
> >> + return chan->device == args->dev && chan->chan_id == args->chan_id;
> >> +}
> >> +
> >> +/**
> >> + * of_dma_xlate_by_chan_id - Translate dt property to DMA channel by channel id
> >> + * @dma_spec: pointer to DMA specifier as found in the device tree
> >> + * @of_dma: pointer to DMA controller data
> >> + *
> >> + * This function can be used as the of xlate callback for DMA driver which want
> >> + * to match the channel based on the channel id. When using this xlate function
> >> + * the #dma-cells propety of the DMA controller dt node needs to be set to 1.
> >> + * The data parameter of of_dma_controller_register must be a pointer to the
> >> + * dma_device struct the function should match uppon.
> >> + *
> >> + * Returns pointer to appropriate dma channel on success or NULL on error.
> >> + */
> >> +struct dma_chan *of_dma_xlate_by_chan_id(struct of_phandle_args *dma_spec,
> >> + struct of_dma *ofdma)
> >> +{
> >> + struct of_dma_filter_by_chan_id_args args;
> >> + dma_cap_mask_t cap;
> >> +
> >> + args.dev = ofdma->of_dma_data;
> >> + if (!args.dev)
> >> + return NULL;
> >> +
> >> + if (dma_spec->args_count != 1)
> >> + return NULL;
> >> +
> >> + dma_cap_zero(cap);
> >> + dma_cap_set(DMA_SLAVE, cap);
> >> +
> >> + args.chan_id = dma_spec->args[0];
> >> +
> >> + return dma_request_channel(cap, of_dma_filter_by_chan_id, &args);
> >> +}
> >> +EXPORT_SYMBOL_GPL(of_dma_xlate_by_chan_id);
> >> diff --git a/include/linux/of_dma.h b/include/linux/of_dma.h
> >> index ce6a8ab..46732d3 100644
> >> --- a/include/linux/of_dma.h
> >> +++ b/include/linux/of_dma.h
> >> @@ -43,6 +43,8 @@ extern struct dma_chan *of_dma_request_slave_channel(struct device_node *np,
> >> const char *name);
> >> extern struct dma_chan *of_dma_simple_xlate(struct of_phandle_args *dma_spec,
> >> struct of_dma *ofdma);
> >> +extern struct dma_chan *of_dma_xlate_by_chan_id(struct of_phandle_args *dma_spec,
> >> + struct of_dma *ofdma);
> >> #else
> >> static inline int of_dma_controller_register(struct device_node *np,
> >> struct dma_chan *(*of_dma_xlate)
> >> @@ -69,6 +71,8 @@ static inline struct dma_chan *of_dma_simple_xlate(struct of_phandle_args *dma_s
> >> return NULL;
> >> }
> >>
> >> +#define of_dma_xlate_by_chan_id NULL
> >> +
> >> #endif
> >>
> >> #endif /* __LINUX_OF_DMA_H */
> >> --
> >> 1.8.0
> >>
>
^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [PATCH 1/2] dma: of: Add generic xlate function for matching by channel id
2013-04-09 11:28 ` Vinod Koul
@ 2013-04-09 12:36 ` Lars-Peter Clausen
2013-04-09 13:06 ` Arnd Bergmann
0 siblings, 1 reply; 7+ messages in thread
From: Lars-Peter Clausen @ 2013-04-09 12:36 UTC (permalink / raw)
To: Vinod Koul
Cc: Arnd Bergmann, Dan Williams, Jon Hunter, Padmavathi Venna, linux-kernel
On 04/09/2013 01:28 PM, Vinod Koul wrote:
> On Sat, Mar 30, 2013 at 09:38:54AM +0100, Lars-Peter Clausen wrote:
>> On 03/29/2013 10:49 PM, Vinod Koul wrote:
>>> On Mon, Mar 25, 2013 at 02:16:51PM +0100, Lars-Peter Clausen wrote:
>>>> This patch adds a new generic of dma xlate callback function which will match a
>>>> channel by its id.
>>> how will the client know which "id" to request?
>>
>> The devicetree tells it, or what exactly do you mean?
> Is this global id? Anrd, what does the id mean in DT?
It's more or less a device specific cookie. And in this case we are using a
1 to 1 mapping to the channel number.
- Lars
>>
>> - Lars
>>
>>>
>>>>
>>>> Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
>>>> ---
>>>> drivers/dma/of-dma.c | 47 +++++++++++++++++++++++++++++++++++++++++++++++
>>>> include/linux/of_dma.h | 4 ++++
>>>> 2 files changed, 51 insertions(+)
>>>>
>>>> diff --git a/drivers/dma/of-dma.c b/drivers/dma/of-dma.c
>>>> index 00db454..7cad4d7 100644
>>>> --- a/drivers/dma/of-dma.c
>>>> +++ b/drivers/dma/of-dma.c
>>>> @@ -269,3 +269,50 @@ struct dma_chan *of_dma_simple_xlate(struct of_phandle_args *dma_spec,
>>>> &dma_spec->args[0]);
>>>> }
>>>> EXPORT_SYMBOL_GPL(of_dma_simple_xlate);
>>>> +
>>>> +struct of_dma_filter_by_chan_id_args {
>>>> + struct dma_device *dev;
>>>> + unsigned int chan_id;
>>>> +};
>>>> +
>>>> +static bool of_dma_filter_by_chan_id(struct dma_chan *chan, void *params)
>>>> +{
>>>> + struct of_dma_filter_by_chan_id_args *args = params;
>>>> +
>>>> + return chan->device == args->dev && chan->chan_id == args->chan_id;
>>>> +}
>>>> +
>>>> +/**
>>>> + * of_dma_xlate_by_chan_id - Translate dt property to DMA channel by channel id
>>>> + * @dma_spec: pointer to DMA specifier as found in the device tree
>>>> + * @of_dma: pointer to DMA controller data
>>>> + *
>>>> + * This function can be used as the of xlate callback for DMA driver which want
>>>> + * to match the channel based on the channel id. When using this xlate function
>>>> + * the #dma-cells propety of the DMA controller dt node needs to be set to 1.
>>>> + * The data parameter of of_dma_controller_register must be a pointer to the
>>>> + * dma_device struct the function should match uppon.
>>>> + *
>>>> + * Returns pointer to appropriate dma channel on success or NULL on error.
>>>> + */
>>>> +struct dma_chan *of_dma_xlate_by_chan_id(struct of_phandle_args *dma_spec,
>>>> + struct of_dma *ofdma)
>>>> +{
>>>> + struct of_dma_filter_by_chan_id_args args;
>>>> + dma_cap_mask_t cap;
>>>> +
>>>> + args.dev = ofdma->of_dma_data;
>>>> + if (!args.dev)
>>>> + return NULL;
>>>> +
>>>> + if (dma_spec->args_count != 1)
>>>> + return NULL;
>>>> +
>>>> + dma_cap_zero(cap);
>>>> + dma_cap_set(DMA_SLAVE, cap);
>>>> +
>>>> + args.chan_id = dma_spec->args[0];
>>>> +
>>>> + return dma_request_channel(cap, of_dma_filter_by_chan_id, &args);
>>>> +}
>>>> +EXPORT_SYMBOL_GPL(of_dma_xlate_by_chan_id);
>>>> diff --git a/include/linux/of_dma.h b/include/linux/of_dma.h
>>>> index ce6a8ab..46732d3 100644
>>>> --- a/include/linux/of_dma.h
>>>> +++ b/include/linux/of_dma.h
>>>> @@ -43,6 +43,8 @@ extern struct dma_chan *of_dma_request_slave_channel(struct device_node *np,
>>>> const char *name);
>>>> extern struct dma_chan *of_dma_simple_xlate(struct of_phandle_args *dma_spec,
>>>> struct of_dma *ofdma);
>>>> +extern struct dma_chan *of_dma_xlate_by_chan_id(struct of_phandle_args *dma_spec,
>>>> + struct of_dma *ofdma);
>>>> #else
>>>> static inline int of_dma_controller_register(struct device_node *np,
>>>> struct dma_chan *(*of_dma_xlate)
>>>> @@ -69,6 +71,8 @@ static inline struct dma_chan *of_dma_simple_xlate(struct of_phandle_args *dma_s
>>>> return NULL;
>>>> }
>>>>
>>>> +#define of_dma_xlate_by_chan_id NULL
>>>> +
>>>> #endif
>>>>
>>>> #endif /* __LINUX_OF_DMA_H */
>>>> --
>>>> 1.8.0
>>>>
>>
^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [PATCH 1/2] dma: of: Add generic xlate function for matching by channel id
2013-04-09 12:36 ` Lars-Peter Clausen
@ 2013-04-09 13:06 ` Arnd Bergmann
0 siblings, 0 replies; 7+ messages in thread
From: Arnd Bergmann @ 2013-04-09 13:06 UTC (permalink / raw)
To: Lars-Peter Clausen
Cc: Vinod Koul, Dan Williams, Jon Hunter, Padmavathi Venna, linux-kernel
On Tuesday 09 April 2013, Lars-Peter Clausen wrote:
> On 04/09/2013 01:28 PM, Vinod Koul wrote:
> > On Sat, Mar 30, 2013 at 09:38:54AM +0100, Lars-Peter Clausen wrote:
> >> On 03/29/2013 10:49 PM, Vinod Koul wrote:
> >>> On Mon, Mar 25, 2013 at 02:16:51PM +0100, Lars-Peter Clausen wrote:
> >>>> This patch adds a new generic of dma xlate callback function which will match a
> >>>> channel by its id.
> >>> how will the client know which "id" to request?
> >>
> >> The devicetree tells it, or what exactly do you mean?
> > Is this global id? Anrd, what does the id mean in DT?
>
> It's more or less a device specific cookie. And in this case we are using a
> 1 to 1 mapping to the channel number.
To clarify this some more: The slave driver uses a name that is defined in the
binding of for the slave device to request a specific channel. This is typically
something trivial like "rx" or "data" that defines how the slave driver knows
its channel.
This gets passed to the dmaengine core, which looks up a dmaengine driver specific
description of a channel, using the name and the slave device pointer as keys.
Normally this is just a request number, sometimes it can be a combinattion
of request number with some other data like a master number or the DMA direction,
if the dmaengine driver requires that information in order to allocate the channel.
In this specific case, it is the chan_id number, which is correct for any driver
that uses the same number for slave_id and chan_id. It may be an exaggeration
to call it "generic", since this only works for a few dmaengine drivers, but
it's reasonable to have this kind of helper in common code since there are
multiple drivers with the same characteristic.
Arnd
^ permalink raw reply [flat|nested] 7+ messages in thread
end of thread, other threads:[~2013-04-09 13:06 UTC | newest]
Thread overview: 7+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2013-03-25 13:16 [PATCH 1/2] dma: of: Add generic xlate function for matching by channel id Lars-Peter Clausen
2013-03-25 13:16 ` [PATCH 2/2] dma: pl330: Use the generic of_dma_xlate_by_chan_id Lars-Peter Clausen
2013-03-29 21:49 ` [PATCH 1/2] dma: of: Add generic xlate function for matching by channel id Vinod Koul
2013-03-30 8:38 ` Lars-Peter Clausen
2013-04-09 11:28 ` Vinod Koul
2013-04-09 12:36 ` Lars-Peter Clausen
2013-04-09 13:06 ` Arnd Bergmann
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