| Message ID | 20190906141816.24095-3-peter.ujfalusi@ti.com (mailing list archive) |
|---|---|
| State | RFC |
| Headers | show |
| Series | dmaengine: Support for DMA domain controllers | expand |
On 06-09-19, 17:18, Peter Ujfalusi wrote: > Find the DMA domain controller of the client device by iterating up in > device tree looking for the closest 'dma-domain-controller' property. > > If the client's node is not provided then check the DT root for the > controller. > > Signed-off-by: Peter Ujfalusi <peter.ujfalusi@ti.com> > --- > drivers/dma/of-dma.c | 42 ++++++++++++++++++++++++++++++++++++++++++ > include/linux/of_dma.h | 7 +++++++ > 2 files changed, 49 insertions(+) > > diff --git a/drivers/dma/of-dma.c b/drivers/dma/of-dma.c > index c2d779daa4b5..04b5795cd76b 100644 > --- a/drivers/dma/of-dma.c > +++ b/drivers/dma/of-dma.c > @@ -18,6 +18,48 @@ > static LIST_HEAD(of_dma_list); > static DEFINE_MUTEX(of_dma_lock); > > +/** > + * of_find_dma_domain - Get the domain DMA controller > + * @np: device node of the client device > + * > + * Look up the DMA controller of the domain the client device is part of. > + * Finds the dma-domain controller the client device belongs to. It is used when > + * requesting non slave channels (like channel for memcpy) to make sure that the > + * channel can be request from a DMA controller which can service the given > + * domain best. > + * > + * Returns the device_node pointer of the DMA controller or succes or NULL on > + * error. > + */ > +struct device_node *of_find_dma_domain(struct device_node *np) > +{ > + struct device_node *dma_domain = NULL; > + phandle dma_phandle; > + > + /* > + * If no device_node is provided look at the root level for system > + * default DMA controller for modules. > + */ > + if (!np) > + np = of_root; > + > + if (!np || !of_node_get(np)) > + return NULL; > + > + do { > + if (of_property_read_u32(np, "dma-domain-controller", > + &dma_phandle)) > + np = of_get_next_parent(np); lets have braces around if as well please > + else { > + dma_domain = of_find_node_by_phandle(dma_phandle); > + of_node_put(np); > + } > + } while (!dma_domain && np); > + > + return dma_domain; > +} > +EXPORT_SYMBOL_GPL(of_find_dma_domain); > + > /** > * of_dma_find_controller - Get a DMA controller in DT DMA helpers list > * @dma_spec: pointer to DMA specifier as found in the device tree > diff --git a/include/linux/of_dma.h b/include/linux/of_dma.h > index fd706cdf255c..6eab0a8d3335 100644 > --- a/include/linux/of_dma.h > +++ b/include/linux/of_dma.h > @@ -32,6 +32,8 @@ struct of_dma_filter_info { > }; > > #ifdef CONFIG_DMA_OF > +extern struct device_node *of_find_dma_domain(struct device_node *np); > + > extern int of_dma_controller_register(struct device_node *np, > struct dma_chan *(*of_dma_xlate) > (struct of_phandle_args *, struct of_dma *), > @@ -52,6 +54,11 @@ extern struct dma_chan *of_dma_xlate_by_chan_id(struct of_phandle_args *dma_spec > struct of_dma *ofdma); > > #else > +static inline struct device_node *of_find_dma_domain(struct device_node *np) > +{ > + return NULL; > +} > + > static inline int of_dma_controller_register(struct device_node *np, > struct dma_chan *(*of_dma_xlate) > (struct of_phandle_args *, struct of_dma *), > -- > Peter > > Texas Instruments Finland Oy, Porkkalankatu 22, 00180 Helsinki. > Y-tunnus/Business ID: 0615521-4. Kotipaikka/Domicile: Helsinki
diff --git a/drivers/dma/of-dma.c b/drivers/dma/of-dma.c index c2d779daa4b5..04b5795cd76b 100644 --- a/drivers/dma/of-dma.c +++ b/drivers/dma/of-dma.c @@ -18,6 +18,48 @@ static LIST_HEAD(of_dma_list); static DEFINE_MUTEX(of_dma_lock); +/** + * of_find_dma_domain - Get the domain DMA controller + * @np: device node of the client device + * + * Look up the DMA controller of the domain the client device is part of. + * Finds the dma-domain controller the client device belongs to. It is used when + * requesting non slave channels (like channel for memcpy) to make sure that the + * channel can be request from a DMA controller which can service the given + * domain best. + * + * Returns the device_node pointer of the DMA controller or succes or NULL on + * error. + */ +struct device_node *of_find_dma_domain(struct device_node *np) +{ + struct device_node *dma_domain = NULL; + phandle dma_phandle; + + /* + * If no device_node is provided look at the root level for system + * default DMA controller for modules. + */ + if (!np) + np = of_root; + + if (!np || !of_node_get(np)) + return NULL; + + do { + if (of_property_read_u32(np, "dma-domain-controller", + &dma_phandle)) + np = of_get_next_parent(np); + else { + dma_domain = of_find_node_by_phandle(dma_phandle); + of_node_put(np); + } + } while (!dma_domain && np); + + return dma_domain; +} +EXPORT_SYMBOL_GPL(of_find_dma_domain); + /** * of_dma_find_controller - Get a DMA controller in DT DMA helpers list * @dma_spec: pointer to DMA specifier as found in the device tree diff --git a/include/linux/of_dma.h b/include/linux/of_dma.h index fd706cdf255c..6eab0a8d3335 100644 --- a/include/linux/of_dma.h +++ b/include/linux/of_dma.h @@ -32,6 +32,8 @@ struct of_dma_filter_info { }; #ifdef CONFIG_DMA_OF +extern struct device_node *of_find_dma_domain(struct device_node *np); + extern int of_dma_controller_register(struct device_node *np, struct dma_chan *(*of_dma_xlate) (struct of_phandle_args *, struct of_dma *), @@ -52,6 +54,11 @@ extern struct dma_chan *of_dma_xlate_by_chan_id(struct of_phandle_args *dma_spec struct of_dma *ofdma); #else +static inline struct device_node *of_find_dma_domain(struct device_node *np) +{ + return NULL; +} + static inline int of_dma_controller_register(struct device_node *np, struct dma_chan *(*of_dma_xlate) (struct of_phandle_args *, struct of_dma *),
Find the DMA domain controller of the client device by iterating up in device tree looking for the closest 'dma-domain-controller' property. If the client's node is not provided then check the DT root for the controller. Signed-off-by: Peter Ujfalusi <peter.ujfalusi@ti.com> --- drivers/dma/of-dma.c | 42 ++++++++++++++++++++++++++++++++++++++++++ include/linux/of_dma.h | 7 +++++++ 2 files changed, 49 insertions(+)