| Message ID | 20250124085221.766303-8-csokas.bence@prolan.hu (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | Add more devm_ functions to simplify probe path in drivers/spi/atmel-quadspi.c | expand |
Hello, Am Fri, Jan 24, 2025 at 09:52:20AM +0100 schrieb Bence Csókás: > Expand the arsenal of devm functions for DMA > devices, this time for requesting channels. > > Signed-off-by: Bence Csókás <csokas.bence@prolan.hu> > --- > drivers/dma/dmaengine.c | 30 ++++++++++++++++++++++++++++++ > include/linux/dmaengine.h | 7 +++++++ > 2 files changed, 37 insertions(+) > > diff --git a/drivers/dma/dmaengine.c b/drivers/dma/dmaengine.c > index c1357d7f3dc6..02c29d26ac85 100644 > --- a/drivers/dma/dmaengine.c > +++ b/drivers/dma/dmaengine.c > @@ -926,6 +926,36 @@ void dma_release_channel(struct dma_chan *chan) > } > EXPORT_SYMBOL_GPL(dma_release_channel); > > +static void dmaenginem_release_channel(void *chan) > +{ > + dma_release_channel(chan); > +} > + > +/** > + * devm_dma_request_chan - try to allocate an exclusive slave channel > + * @dev: pointer to client device structure > + * @name: slave channel name > + * > + * Returns pointer to appropriate DMA channel on success or an error pointer. > + * > + * The operation is managed and will be undone on driver detach. > + */ > + > +struct dma_chan *devm_dma_request_chan(struct device *dev, const char *name) > +{ > + struct dma_chan *chan = dma_request_chan(dev, name); > + int ret = 0; > + > + if (!IS_ERR(chan)) > + ret = devm_add_action_or_reset(dev, dmaenginem_release_channel, chan); Why not using dma_release_channel() directly here? What's the point of introducing dmaenginem_release_channel() further above? Greets Alex > + > + if (ret) > + return ERR_PTR(ret); > + > + return chan; > +} > +EXPORT_SYMBOL_GPL(devm_dma_request_chan); > + > /** > * dmaengine_get - register interest in dma_channels > */ > diff --git a/include/linux/dmaengine.h b/include/linux/dmaengine.h > index 346251bf1026..ffb54b52ef0c 100644 > --- a/include/linux/dmaengine.h > +++ b/include/linux/dmaengine.h > @@ -1528,6 +1528,7 @@ struct dma_chan *__dma_request_channel(const dma_cap_mask_t *mask, > > struct dma_chan *dma_request_chan(struct device *dev, const char *name); > struct dma_chan *dma_request_chan_by_mask(const dma_cap_mask_t *mask); > +struct dma_chan *devm_dma_request_chan(struct device *dev, const char *name); > > void dma_release_channel(struct dma_chan *chan); > int dma_get_slave_caps(struct dma_chan *chan, struct dma_slave_caps *caps); > @@ -1564,6 +1565,12 @@ static inline struct dma_chan *dma_request_chan_by_mask( > { > return ERR_PTR(-ENODEV); > } > + > +static inline struct dma_chan *devm_dma_request_chan(struct device *dev, const char *name) > +{ > + return ERR_PTR(-ENODEV); > +} > + > static inline void dma_release_channel(struct dma_chan *chan) > { > } > -- > 2.48.1 > > >
Hi, On 2025. 02. 03. 13:27, Alexander Dahl wrote: >> + if (!IS_ERR(chan)) >> + ret = devm_add_action_or_reset(dev, dmaenginem_release_channel, chan); > > Why not using dma_release_channel() directly here? What's the point > of introducing dmaenginem_release_channel() further above? I followed the existing practice, used by `dmaenginem_async_device_unregister()`. I suspect it was done like this because the devm callback function's signature takes a `void *` and not `struct dma_chan *`. Bence
diff --git a/drivers/dma/dmaengine.c b/drivers/dma/dmaengine.c index c1357d7f3dc6..02c29d26ac85 100644 --- a/drivers/dma/dmaengine.c +++ b/drivers/dma/dmaengine.c @@ -926,6 +926,36 @@ void dma_release_channel(struct dma_chan *chan) } EXPORT_SYMBOL_GPL(dma_release_channel); +static void dmaenginem_release_channel(void *chan) +{ + dma_release_channel(chan); +} + +/** + * devm_dma_request_chan - try to allocate an exclusive slave channel + * @dev: pointer to client device structure + * @name: slave channel name + * + * Returns pointer to appropriate DMA channel on success or an error pointer. + * + * The operation is managed and will be undone on driver detach. + */ + +struct dma_chan *devm_dma_request_chan(struct device *dev, const char *name) +{ + struct dma_chan *chan = dma_request_chan(dev, name); + int ret = 0; + + if (!IS_ERR(chan)) + ret = devm_add_action_or_reset(dev, dmaenginem_release_channel, chan); + + if (ret) + return ERR_PTR(ret); + + return chan; +} +EXPORT_SYMBOL_GPL(devm_dma_request_chan); + /** * dmaengine_get - register interest in dma_channels */ diff --git a/include/linux/dmaengine.h b/include/linux/dmaengine.h index 346251bf1026..ffb54b52ef0c 100644 --- a/include/linux/dmaengine.h +++ b/include/linux/dmaengine.h @@ -1528,6 +1528,7 @@ struct dma_chan *__dma_request_channel(const dma_cap_mask_t *mask, struct dma_chan *dma_request_chan(struct device *dev, const char *name); struct dma_chan *dma_request_chan_by_mask(const dma_cap_mask_t *mask); +struct dma_chan *devm_dma_request_chan(struct device *dev, const char *name); void dma_release_channel(struct dma_chan *chan); int dma_get_slave_caps(struct dma_chan *chan, struct dma_slave_caps *caps); @@ -1564,6 +1565,12 @@ static inline struct dma_chan *dma_request_chan_by_mask( { return ERR_PTR(-ENODEV); } + +static inline struct dma_chan *devm_dma_request_chan(struct device *dev, const char *name) +{ + return ERR_PTR(-ENODEV); +} + static inline void dma_release_channel(struct dma_chan *chan) { }
Expand the arsenal of devm functions for DMA devices, this time for requesting channels. Signed-off-by: Bence Csókás <csokas.bence@prolan.hu> --- drivers/dma/dmaengine.c | 30 ++++++++++++++++++++++++++++++ include/linux/dmaengine.h | 7 +++++++ 2 files changed, 37 insertions(+)