summaryrefslogtreecommitdiff
path: root/sound/core
diff options
context:
space:
mode:
authorTakashi Iwai <tiwai@suse.de>2021-07-15 10:58:25 +0300
committerTakashi Iwai <tiwai@suse.de>2021-07-19 17:16:34 +0300
commitc2b94954add3cb25b40a9aa8badd196671d9872b (patch)
tree89809a72a67ffec8c3056e9765aed56221983747 /sound/core
parente8ad415b7a55cb9a9fbfc04696518d5ea0b609b3 (diff)
downloadlinux-c2b94954add3cb25b40a9aa8badd196671d9872b.tar.xz
ALSA: core: Add device-managed request_dma()
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. Link: https://lore.kernel.org/r/20210715075941.23332-4-tiwai@suse.de Signed-off-by: Takashi Iwai <tiwai@suse.de>
Diffstat (limited to 'sound/core')
-rw-r--r--sound/core/isadma.c38
1 files changed, 38 insertions, 0 deletions
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);