ASoC: mt8188: add memory-region support

Merge series from Trevor Wu <trevor.wu@mediatek.com>:

This series introduces support for memory-region, allowing afe memif to
utilize the region specified in dts.

Documentation/devicetree/bindings/sound/mediatek,mt8188-afe.yaml

@@ -25,6 +25,12 @@ properties:
   reset-names:
     const: audiosys
 
+  memory-region:
+    maxItems: 1
+    description: |
+      Shared memory region for AFE memif.  A "shared-dma-pool".
+      See ../reserved-memory/reserved-memory.yaml for details.
+
   mediatek,topckgen:
     $ref: /schemas/types.yaml#/definitions/phandle
     description: The phandle of the mediatek topckgen controller
@@ -176,6 +182,7 @@ examples:
         interrupts = <GIC_SPI 822 IRQ_TYPE_LEVEL_HIGH 0>;
         resets = <&watchdog 14>;
         reset-names = "audiosys";
+        memory-region = <&snd_dma_mem_reserved>;
         mediatek,topckgen = <&topckgen>;
         mediatek,infracfg = <&infracfg_ao>;
         power-domains = <&spm 13>; //MT8188_POWER_DOMAIN_AUDIO

sound/soc/mediatek/mt8188/mt8188-afe-pcm.c

@@ -16,6 +16,7 @@
 #include <linux/of.h>
 #include <linux/of_address.h>
 #include <linux/of_platform.h>
+#include <linux/of_reserved_mem.h>
 #include <linux/pm_runtime.h>
 #include <linux/soc/mediatek/infracfg.h>
 #include <linux/reset.h>
@@ -3193,11 +3194,15 @@ static int mt8188_afe_pcm_dev_probe(struct platform_device *pdev)
 {
 	struct mtk_base_afe *afe;
 	struct mt8188_afe_private *afe_priv;
-	struct device *dev;
+	struct device *dev = &pdev->dev;
 	struct reset_control *rstc;
 	struct regmap *infra_ao;
 	int i, irq_id, ret;
 
+	ret = of_reserved_mem_device_init(dev);
+	if (ret)
+		dev_dbg(dev, "failed to assign memory region: %d\n", ret);
+
 	ret = dma_set_mask_and_coherent(&pdev->dev, DMA_BIT_MASK(33));
 	if (ret)
 		return ret;
@@ -3213,7 +3218,6 @@ static int mt8188_afe_pcm_dev_probe(struct platform_device *pdev)
 
 	afe_priv = afe->platform_priv;
 	afe->dev = &pdev->dev;
-	dev = afe->dev;
 
 	afe->base_addr = devm_platform_ioremap_resource(pdev, 0);
 	if (IS_ERR(afe->base_addr))