ASoC: sprd: Add reserved DMA memory support

For Spreadtrum audio platform driver, it need allocate a larger DMA buffer
dynamically to copy audio data between userspace and kernel space, but that
will increase the risk of memory allocation failure especially the system
is under heavy load situation.

To make sure the audio can work in this scenario, we usually reserve one
region of memory to be used as a shared pool of DMA buffers for the
platform component. So add of_reserved_mem_device_init_by_idx() function
to initialize the shared pool of DMA buffers to be used by the platform
component.

Signed-off-by: Baolin Wang <baolin.wang@linaro.org>
Signed-off-by: Mark Brown <broonie@kernel.org>

diff --git a/sound/soc/sprd/sprd-pcm-dma.c b/sound/soc/sprd/sprd-pcm-dma.c
index 9be6d4b2bf742514c79a18b77d3a54270d1f0ae9..d38ebbbbf16987a858d0fc8d32c3468cd379cf4c 100644 (file)
--- a/sound/soc/sprd/sprd-pcm-dma.c
+++ b/sound/soc/sprd/sprd-pcm-dma.c
@@ -6,6 +6,7 @@
 #include <linux/dma/sprd-dma.h>
 #include <linux/kernel.h>
 #include <linux/module.h>
+#include <linux/of_reserved_mem.h>
 #include <linux/platform_device.h>
 #include <sound/pcm.h>
 #include <sound/pcm_params.h>
@@ -530,8 +531,14 @@ static const struct snd_soc_component_driver sprd_soc_component = {
 
 static int sprd_soc_platform_probe(struct platform_device *pdev)
 {
+       struct device_node *np = pdev->dev.of_node;
        int ret;
 
+       ret = of_reserved_mem_device_init_by_idx(&pdev->dev, np, 0);
+       if (ret)
+               dev_warn(&pdev->dev,
+                        "no reserved DMA memory for audio platform device\n");
+
        ret = devm_snd_soc_register_component(&pdev->dev, &sprd_soc_component,
                                              NULL, 0);
        if (ret)