This patch adds a devres-supported helper for requesting an ISA DMA
channel that will be automatically freed at the device unbinding.
It'll be used by quite a few ISA sound drivers.
Signed-off-by: Takashi Iwai <tiwai@xxxxxxx>
---
include/sound/core.h | 1 +
sound/core/isadma.c | 38 ++++++++++++++++++++++++++++++++++++++
2 files changed, 39 insertions(+)
diff --git a/include/sound/core.h b/include/sound/core.h
index 7885f903cd5a..b7e9b58d3c78 100644
--- a/include/sound/core.h
+++ b/include/sound/core.h
@@ -329,6 +329,7 @@ int snd_device_get_state(struct snd_card *card, void *device_data);
void snd_dma_program(unsigned long dma, unsigned long addr, unsigned int size, unsigned short mode);
void snd_dma_disable(unsigned long dma);
unsigned int snd_dma_pointer(unsigned long dma, unsigned int size);
+int snd_devm_request_dma(struct device *dev, int dma, const char *name);
#endif
/* misc.c */
diff --git a/sound/core/isadma.c b/sound/core/isadma.c
index c3d789ef6975..1f45ede023b4 100644
--- a/sound/core/isadma.c
+++ b/sound/core/isadma.c
@@ -97,3 +97,41 @@ unsigned int snd_dma_pointer(unsigned long dma, unsigned int size)
return size - result;
}
EXPORT_SYMBOL(snd_dma_pointer);
+
+struct snd_dma_data {
+ int dma;
+};
+
+static void __snd_release_dma(struct device *dev, void *data)
+{
+ struct snd_dma_data *p = data;
+
+ snd_dma_disable(p->dma);
+ free_dma(p->dma);
+}
+
+/**
+ * snd_devm_request_dma - the managed version of request_dma()
+ * @dev: the device pointer
+ * @dma: the dma number
+ * @name: the name string of the requester
+ *
+ * Returns zero on success, or a negative error code.
+ * The requested DMA will be automatically released at unbinding via devres.
+ */
+int snd_devm_request_dma(struct device *dev, int dma, const char *name)
+{
+ struct snd_dma_data *p;
+
+ if (request_dma(dma, name))
+ return -EBUSY;
+ p = devres_alloc(__snd_release_dma, sizeof(*p), GFP_KERNEL);
+ if (!p) {
+ free_dma(dma);
+ return -ENOMEM;
+ }
+ p->dma = dma;
+ devres_add(dev, p);
+ return 0;
+}
+EXPORT_SYMBOL_GPL(snd_devm_request_dma);
--
2.26.2
