Update the documentation to follow the recent change of the memory allocation helpers. The macro snd_dma_continuous_data() is gone, and the driver needs to set up the coherent dma mask for allocating in the lower memory addresses, instead. Signed-off-by: Takashi Iwai <tiwai@xxxxxxx> --- .../kernel-api/writing-an-alsa-driver.rst | 21 +++++++------------ 1 file changed, 8 insertions(+), 13 deletions(-) diff --git a/Documentation/sound/kernel-api/writing-an-alsa-driver.rst b/Documentation/sound/kernel-api/writing-an-alsa-driver.rst index 176b73583b7a..07a620c5ca74 100644 --- a/Documentation/sound/kernel-api/writing-an-alsa-driver.rst +++ b/Documentation/sound/kernel-api/writing-an-alsa-driver.rst @@ -3565,13 +3565,17 @@ given size. The second argument (type) and the third argument (device pointer) are dependent on the bus. For normal devices, pass the device pointer (typically identical as ``card->dev``) to the third argument with -``SNDRV_DMA_TYPE_DEV`` type. For the continuous buffer unrelated to the +``SNDRV_DMA_TYPE_DEV`` type. + +For the continuous buffer unrelated to the bus can be pre-allocated with ``SNDRV_DMA_TYPE_CONTINUOUS`` type. You can pass NULL to the device pointer in that case, which is the default mode implying to allocate with ``GFP_KERNEL`` flag. -If you need a different GFP flag, you can pass it by encoding the flag -into the device pointer via a special macro -:c:func:`snd_dma_continuous_data()`. +If you need a restricted (lower) address, set up the coherent DMA mask +bits for the device, and pass the device pointer, like the normal +device memory allocations. For this type, it's still allowed to pass +NULL to the device pointer, too, if no address restriction is needed. + For the scatter-gather buffers, use ``SNDRV_DMA_TYPE_DEV_SG`` with the device pointer (see the `Non-Contiguous Buffers`_ section). @@ -3811,15 +3815,6 @@ arguments here. Since each vmalloc call should succeed at any time, we don't need to pre-allocate the buffers like other continuous pages. -If you need the 32bit DMA allocation, pass the device pointer encoded -by :c:func:`snd_dma_continuous_data()` with ``GFP_KERNEL|__GFP_DMA32`` -argument. - -:: - - snd_pcm_set_managed_buffer_all(pcm, SNDRV_DMA_TYPE_VMALLOC, - snd_dma_continuous_data(GFP_KERNEL | __GFP_DMA32), 0, 0); - Proc Interface ============== -- 2.35.3
