ASoC: AMD: add AMD ASoC ACP 2.x DMA driver

ACP IP has internal DMA controller with multiple channels which
can be programmed in cyclic/non cyclic manner. ACP can generate
interrupt upon completion of DMA transfer, if required.
The PCM driver provides the platform DMA component to ALSA core.

Signed-off-by: Maruthi Bayyavarapu <[e-mail]>
Reviewed-by: Alex Deucher <[e-mail]>
Reviewed-by: Murali Krishna Vemuri <[e-mail]>
Signed-off-by: Alex Deucher <[e-mail]>
Signed-off-by: Mark Brown <[e-mail]>

sound/soc/Kconfig

···
 
 # All the supported SoCs
 source "sound/soc/adi/Kconfig"
+source "sound/soc/amd/Kconfig"
 source "sound/soc/atmel/Kconfig"
 source "sound/soc/au1x/Kconfig"
 source "sound/soc/bcm/Kconfig"

sound/soc/Makefile

···
 obj-$(CONFIG_SND_SOC)	+= codecs/
 obj-$(CONFIG_SND_SOC)	+= generic/
 obj-$(CONFIG_SND_SOC)	+= adi/
+obj-$(CONFIG_SND_SOC)	+= amd/
 obj-$(CONFIG_SND_SOC)	+= atmel/
 obj-$(CONFIG_SND_SOC)	+= au1x/
 obj-$(CONFIG_SND_SOC)	+= bcm/

sound/soc/amd/Kconfig

···
+config SND_SOC_AMD_ACP
+	tristate "AMD Audio Coprocessor support"
+	help
+	 This option enables ACP DMA support on AMD platform.

sound/soc/amd/Makefile

···
+snd-soc-acp-pcm-objs	:= acp-pcm-dma.o
+
+obj-$(CONFIG_SND_SOC_AMD_ACP) += snd-soc-acp-pcm.o

sound/soc/amd/acp-pcm-dma.c

···
+/*
+ * AMD ALSA SoC PCM Driver for ACP 2.x
+ *
+ * Copyright 2014-2015 Advanced Micro Devices, Inc.
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
+ * more details.
+ */
+
+#include <linux/module.h>
+#include <linux/delay.h>
+#include <linux/sizes.h>
+
+#include <sound/soc.h>
+
+#include "acp.h"
+
+#define PLAYBACK_MIN_NUM_PERIODS    2
+#define PLAYBACK_MAX_NUM_PERIODS    2
+#define PLAYBACK_MAX_PERIOD_SIZE    16384
+#define PLAYBACK_MIN_PERIOD_SIZE    1024
+#define CAPTURE_MIN_NUM_PERIODS     2
+#define CAPTURE_MAX_NUM_PERIODS     2
+#define CAPTURE_MAX_PERIOD_SIZE     16384
+#define CAPTURE_MIN_PERIOD_SIZE     1024
+
+#define MAX_BUFFER (PLAYBACK_MAX_PERIOD_SIZE * PLAYBACK_MAX_NUM_PERIODS)
+#define MIN_BUFFER MAX_BUFFER
+
+static const struct snd_pcm_hardware acp_pcm_hardware_playback = {
+	.info = SNDRV_PCM_INFO_INTERLEAVED |
+		SNDRV_PCM_INFO_BLOCK_TRANSFER | SNDRV_PCM_INFO_MMAP |
+		SNDRV_PCM_INFO_MMAP_VALID | SNDRV_PCM_INFO_BATCH |
+		SNDRV_PCM_INFO_PAUSE | SNDRV_PCM_INFO_RESUME,
+	.formats = SNDRV_PCM_FMTBIT_S16_LE |
+		SNDRV_PCM_FMTBIT_S24_LE | SNDRV_PCM_FMTBIT_S32_LE,
+	.channels_min = 1,
+	.channels_max = 8,
+	.rates = SNDRV_PCM_RATE_8000_96000,
+	.rate_min = 8000,
+	.rate_max = 96000,
+	.buffer_bytes_max = PLAYBACK_MAX_NUM_PERIODS * PLAYBACK_MAX_PERIOD_SIZE,
+	.period_bytes_min = PLAYBACK_MIN_PERIOD_SIZE,
+	.period_bytes_max = PLAYBACK_MAX_PERIOD_SIZE,
+	.periods_min = PLAYBACK_MIN_NUM_PERIODS,
+	.periods_max = PLAYBACK_MAX_NUM_PERIODS,
+};
+
+static const struct snd_pcm_hardware acp_pcm_hardware_capture = {
+	.info = SNDRV_PCM_INFO_INTERLEAVED |
+		SNDRV_PCM_INFO_BLOCK_TRANSFER | SNDRV_PCM_INFO_MMAP |
+		SNDRV_PCM_INFO_MMAP_VALID | SNDRV_PCM_INFO_BATCH |
+	    SNDRV_PCM_INFO_PAUSE | SNDRV_PCM_INFO_RESUME,
+	.formats = SNDRV_PCM_FMTBIT_S16_LE |
+		SNDRV_PCM_FMTBIT_S24_LE | SNDRV_PCM_FMTBIT_S32_LE,
+	.channels_min = 1,
+	.channels_max = 2,
+	.rates = SNDRV_PCM_RATE_8000_48000,
+	.rate_min = 8000,
+	.rate_max = 48000,
+	.buffer_bytes_max = CAPTURE_MAX_NUM_PERIODS * CAPTURE_MAX_PERIOD_SIZE,
+	.period_bytes_min = CAPTURE_MIN_PERIOD_SIZE,
+	.period_bytes_max = CAPTURE_MAX_PERIOD_SIZE,
+	.periods_min = CAPTURE_MIN_NUM_PERIODS,
+	.periods_max = CAPTURE_MAX_NUM_PERIODS,
+};
+
+struct audio_drv_data {
+	struct snd_pcm_substream *play_stream;
+	struct snd_pcm_substream *capture_stream;
+	void __iomem *acp_mmio;
+};
+
+static u32 acp_reg_read(void __iomem *acp_mmio, u32 reg)
+{
+	return readl(acp_mmio + (reg * 4));
+}
+
+static void acp_reg_write(u32 val, void __iomem *acp_mmio, u32 reg)
+{
+	writel(val, acp_mmio + (reg * 4));
+}
+
+/* Configure a given dma channel parameters - enable/disble,
+ * number of descriptors, priority
+ */
+static void config_acp_dma_channel(void __iomem *acp_mmio, u8 ch_num,
+				   u16 dscr_strt_idx, u16 num_dscrs,
+				   enum acp_dma_priority_level priority_level)
+{
+	u32 dma_ctrl;
+
+	/* disable the channel run field */
+	dma_ctrl = acp_reg_read(acp_mmio, mmACP_DMA_CNTL_0 + ch_num);
+	dma_ctrl &= ~ACP_DMA_CNTL_0__DMAChRun_MASK;
+	acp_reg_write(dma_ctrl, acp_mmio, mmACP_DMA_CNTL_0 + ch_num);
+
+	/* program a DMA channel with first descriptor to be processed. */
+	acp_reg_write((ACP_DMA_DSCR_STRT_IDX_0__DMAChDscrStrtIdx_MASK
+			& dscr_strt_idx),
+			acp_mmio, mmACP_DMA_DSCR_STRT_IDX_0 + ch_num);
+
+	/* program a DMA channel with the number of descriptors to be
+	 * processed in the transfer
+	*/
+	acp_reg_write(ACP_DMA_DSCR_CNT_0__DMAChDscrCnt_MASK & num_dscrs,
+		acp_mmio, mmACP_DMA_DSCR_CNT_0 + ch_num);
+
+	/* set DMA channel priority */
+	acp_reg_write(priority_level, acp_mmio, mmACP_DMA_PRIO_0 + ch_num);
+}
+
+/* Initialize a dma descriptor in SRAM based on descritor information passed */
+static void config_dma_descriptor_in_sram(void __iomem *acp_mmio,
+					  u16 descr_idx,
+					  acp_dma_dscr_transfer_t *descr_info)
+{
+	u32 sram_offset;
+
+	sram_offset = (descr_idx * sizeof(acp_dma_dscr_transfer_t));
+
+	/* program the source base address. */
+	acp_reg_write(sram_offset, acp_mmio, mmACP_SRBM_Targ_Idx_Addr);
+	acp_reg_write(descr_info->src,	acp_mmio, mmACP_SRBM_Targ_Idx_Data);
+	/* program the destination base address. */
+	acp_reg_write(sram_offset + 4,	acp_mmio, mmACP_SRBM_Targ_Idx_Addr);
+	acp_reg_write(descr_info->dest, acp_mmio, mmACP_SRBM_Targ_Idx_Data);
+
+	/* program the number of bytes to be transferred for this descriptor. */
+	acp_reg_write(sram_offset + 8,	acp_mmio, mmACP_SRBM_Targ_Idx_Addr);
+	acp_reg_write(descr_info->xfer_val, acp_mmio, mmACP_SRBM_Targ_Idx_Data);
+}
+
+/* Initialize the DMA descriptor information for transfer between
+ * system memory <-> ACP SRAM
+ */
+static void set_acp_sysmem_dma_descriptors(void __iomem *acp_mmio,
+					   u32 size, int direction,
+					   u32 pte_offset)
+{
+	u16 i;
+	u16 dma_dscr_idx = PLAYBACK_START_DMA_DESCR_CH12;
+	acp_dma_dscr_transfer_t dmadscr[NUM_DSCRS_PER_CHANNEL];
+
+	for (i = 0; i < NUM_DSCRS_PER_CHANNEL; i++) {
+		dmadscr[i].xfer_val = 0;
+		if (direction == SNDRV_PCM_STREAM_PLAYBACK) {
+			dma_dscr_idx = PLAYBACK_START_DMA_DESCR_CH12 + i;
+			dmadscr[i].dest = ACP_SHARED_RAM_BANK_1_ADDRESS +
+					(size / 2) - (i * (size/2));
+			dmadscr[i].src = ACP_INTERNAL_APERTURE_WINDOW_0_ADDRESS
+				+ (pte_offset * SZ_4K) + (i * (size/2));
+			dmadscr[i].xfer_val |=
+			(ACP_DMA_ATTRIBUTES_DAGB_ONION_TO_SHAREDMEM << 16) |
+			(size / 2);
+		} else {
+			dma_dscr_idx = CAPTURE_START_DMA_DESCR_CH14 + i;
+			dmadscr[i].src = ACP_SHARED_RAM_BANK_5_ADDRESS +
+					(i * (size/2));
+			dmadscr[i].dest = ACP_INTERNAL_APERTURE_WINDOW_0_ADDRESS
+						+ (pte_offset * SZ_4K) +
+						(i * (size/2));
+			dmadscr[i].xfer_val |=
+			BIT(22) |
+			(ACP_DMA_ATTRIBUTES_SHAREDMEM_TO_DAGB_ONION << 16) |
+			(size / 2);
+		}
+		config_dma_descriptor_in_sram(acp_mmio, dma_dscr_idx,
+						&dmadscr[i]);
+	}
+	if (direction == SNDRV_PCM_STREAM_PLAYBACK)
+		config_acp_dma_channel(acp_mmio, SYSRAM_TO_ACP_CH_NUM,
+					PLAYBACK_START_DMA_DESCR_CH12,
+					NUM_DSCRS_PER_CHANNEL,
+					ACP_DMA_PRIORITY_LEVEL_NORMAL);
+	else
+		config_acp_dma_channel(acp_mmio, ACP_TO_SYSRAM_CH_NUM,
+					CAPTURE_START_DMA_DESCR_CH14,
+					NUM_DSCRS_PER_CHANNEL,
+					ACP_DMA_PRIORITY_LEVEL_NORMAL);
+}
+
+/* Initialize the DMA descriptor information for transfer between
+ * ACP SRAM <-> I2S
+ */
+static void set_acp_to_i2s_dma_descriptors(void __iomem *acp_mmio,
+					   u32 size, int direction)
+{
+
+	u16 i;
+	u16 dma_dscr_idx = PLAYBACK_START_DMA_DESCR_CH13;
+	acp_dma_dscr_transfer_t dmadscr[NUM_DSCRS_PER_CHANNEL];
+
+	for (i = 0; i < NUM_DSCRS_PER_CHANNEL; i++) {
+		dmadscr[i].xfer_val = 0;
+		if (direction == SNDRV_PCM_STREAM_PLAYBACK) {
+			dma_dscr_idx = PLAYBACK_START_DMA_DESCR_CH13 + i;
+			dmadscr[i].src = ACP_SHARED_RAM_BANK_1_ADDRESS +
+					 (i * (size/2));
+			/* dmadscr[i].dest is unused by hardware. */
+			dmadscr[i].dest = 0;
+			dmadscr[i].xfer_val |= BIT(22) | (TO_ACP_I2S_1 << 16) |
+						(size / 2);
+		} else {
+			dma_dscr_idx = CAPTURE_START_DMA_DESCR_CH15 + i;
+			/* dmadscr[i].src is unused by hardware. */
+			dmadscr[i].src = 0;
+			dmadscr[i].dest = ACP_SHARED_RAM_BANK_5_ADDRESS +
+					(i * (size / 2));
+			dmadscr[i].xfer_val |= BIT(22) |
+					(FROM_ACP_I2S_1 << 16) | (size / 2);
+		}
+		config_dma_descriptor_in_sram(acp_mmio, dma_dscr_idx,
+						&dmadscr[i]);
+	}
+	/* Configure the DMA channel with the above descriptore */
+	if (direction == SNDRV_PCM_STREAM_PLAYBACK)
+		config_acp_dma_channel(acp_mmio, ACP_TO_I2S_DMA_CH_NUM,
+					PLAYBACK_START_DMA_DESCR_CH13,
+					NUM_DSCRS_PER_CHANNEL,
+					ACP_DMA_PRIORITY_LEVEL_NORMAL);
+	else
+		config_acp_dma_channel(acp_mmio, I2S_TO_ACP_DMA_CH_NUM,
+					CAPTURE_START_DMA_DESCR_CH15,
+					NUM_DSCRS_PER_CHANNEL,
+					ACP_DMA_PRIORITY_LEVEL_NORMAL);
+}
+
+/* Create page table entries in ACP SRAM for the allocated memory */
+static void acp_pte_config(void __iomem *acp_mmio, struct page *pg,
+			   u16 num_of_pages, u32 pte_offset)
+{
+	u16 page_idx;
+	u64 addr;
+	u32 low;
+	u32 high;
+	u32 offset;
+
+	offset	= ACP_DAGB_GRP_SRBM_SRAM_BASE_OFFSET + (pte_offset * 8);
+	for (page_idx = 0; page_idx < (num_of_pages); page_idx++) {
+		/* Load the low address of page int ACP SRAM through SRBM */
+		acp_reg_write((offset + (page_idx * 8)),
+			acp_mmio, mmACP_SRBM_Targ_Idx_Addr);
+		addr = page_to_phys(pg);
+
+		low = lower_32_bits(addr);
+		high = upper_32_bits(addr);
+
+		acp_reg_write(low, acp_mmio, mmACP_SRBM_Targ_Idx_Data);
+
+		/* Load the High address of page int ACP SRAM through SRBM */
+		acp_reg_write((offset + (page_idx * 8) + 4),
+			acp_mmio, mmACP_SRBM_Targ_Idx_Addr);
+
+		/* page enable in ACP */
+		high |= BIT(31);
+		acp_reg_write(high, acp_mmio, mmACP_SRBM_Targ_Idx_Data);
+
+		/* Move to next physically contiguos page */
+		pg++;
+	}
+}
+
+static void config_acp_dma(void __iomem *acp_mmio,
+			   struct audio_substream_data *audio_config)
+{
+	u32 pte_offset;
+
+	if (audio_config->direction == SNDRV_PCM_STREAM_PLAYBACK)
+		pte_offset = ACP_PLAYBACK_PTE_OFFSET;
+	else
+		pte_offset = ACP_CAPTURE_PTE_OFFSET;
+
+	acp_pte_config(acp_mmio, audio_config->pg, audio_config->num_of_pages,
+			pte_offset);
+
+	/* Configure System memory <-> ACP SRAM DMA descriptors */
+	set_acp_sysmem_dma_descriptors(acp_mmio, audio_config->size,
+				       audio_config->direction, pte_offset);
+
+	/* Configure ACP SRAM <-> I2S DMA descriptors */
+	set_acp_to_i2s_dma_descriptors(acp_mmio, audio_config->size,
+					audio_config->direction);
+}
+
+/* Start a given DMA channel transfer */
+static void acp_dma_start(void __iomem *acp_mmio,
+			 u16 ch_num, bool is_circular)
+{
+	u32 dma_ctrl;
+
+	/* read the dma control register and disable the channel run field */
+	dma_ctrl = acp_reg_read(acp_mmio, mmACP_DMA_CNTL_0 + ch_num);
+
+	/* Invalidating the DAGB cache */
+	acp_reg_write(1, acp_mmio, mmACP_DAGB_ATU_CTRL);
+
+	/* configure the DMA channel and start the DMA transfer
+	 * set dmachrun bit to start the transfer and enable the
+	 * interrupt on completion of the dma transfer
+	 */
+	dma_ctrl |= ACP_DMA_CNTL_0__DMAChRun_MASK;
+
+	switch (ch_num) {
+	case ACP_TO_I2S_DMA_CH_NUM:
+	case ACP_TO_SYSRAM_CH_NUM:
+	case I2S_TO_ACP_DMA_CH_NUM:
+		dma_ctrl |= ACP_DMA_CNTL_0__DMAChIOCEn_MASK;
+		break;
+	default:
+		dma_ctrl &= ~ACP_DMA_CNTL_0__DMAChIOCEn_MASK;
+		break;
+	}
+
+	/* enable  for ACP SRAM to/from I2S DMA channel */
+	if (is_circular == true)
+		dma_ctrl |= ACP_DMA_CNTL_0__Circular_DMA_En_MASK;
+	else
+		dma_ctrl &= ~ACP_DMA_CNTL_0__Circular_DMA_En_MASK;
+
+	acp_reg_write(dma_ctrl, acp_mmio, mmACP_DMA_CNTL_0 + ch_num);
+}
+
+/* Stop a given DMA channel transfer */
+static int acp_dma_stop(void __iomem *acp_mmio, u8 ch_num)
+{
+	u32 dma_ctrl;
+	u32 dma_ch_sts;
+	u32 count = ACP_DMA_RESET_TIME;
+
+	dma_ctrl = acp_reg_read(acp_mmio, mmACP_DMA_CNTL_0 + ch_num);
+
+	/* clear the dma control register fields before writing zero
+	 * in reset bit
+	*/
+	dma_ctrl &= ~ACP_DMA_CNTL_0__DMAChRun_MASK;
+	dma_ctrl &= ~ACP_DMA_CNTL_0__DMAChIOCEn_MASK;
+
+	acp_reg_write(dma_ctrl, acp_mmio, mmACP_DMA_CNTL_0 + ch_num);
+	dma_ch_sts = acp_reg_read(acp_mmio, mmACP_DMA_CH_STS);
+
+	if (dma_ch_sts & BIT(ch_num)) {
+		/* set the reset bit for this channel to stop the dma
+		*  transfer
+		*/
+		dma_ctrl |= ACP_DMA_CNTL_0__DMAChRst_MASK;
+		acp_reg_write(dma_ctrl, acp_mmio, mmACP_DMA_CNTL_0 + ch_num);
+	}
+
+	/* check the channel status bit for some time and return the status */
+	while (true) {
+		dma_ch_sts = acp_reg_read(acp_mmio, mmACP_DMA_CH_STS);
+		if (!(dma_ch_sts & BIT(ch_num))) {
+			/* clear the reset flag after successfully stopping
+			* the dma transfer and break from the loop
+			*/
+			dma_ctrl &= ~ACP_DMA_CNTL_0__DMAChRst_MASK;
+
+			acp_reg_write(dma_ctrl, acp_mmio, mmACP_DMA_CNTL_0
+								+ ch_num);
+			break;
+		}
+		if (--count == 0) {
+			pr_err("Failed to stop ACP DMA channel : %d\n", ch_num);
+			return -ETIMEDOUT;
+		}
+		udelay(100);
+	}
+	return 0;
+}
+
+/* Initialize and bring ACP hardware to default state. */
+static int acp_init(void __iomem *acp_mmio)
+{
+	u32 val, count, sram_pte_offset;
+
+	/* Assert Soft reset of ACP */
+	val = acp_reg_read(acp_mmio, mmACP_SOFT_RESET);
+
+	val |= ACP_SOFT_RESET__SoftResetAud_MASK;
+	acp_reg_write(val, acp_mmio, mmACP_SOFT_RESET);
+
+	count = ACP_SOFT_RESET_DONE_TIME_OUT_VALUE;
+	while (true) {
+		val = acp_reg_read(acp_mmio, mmACP_SOFT_RESET);
+		if (ACP_SOFT_RESET__SoftResetAudDone_MASK ==
+		    (val & ACP_SOFT_RESET__SoftResetAudDone_MASK))
+			break;
+		if (--count == 0) {
+			pr_err("Failed to reset ACP\n");
+			return -ETIMEDOUT;
+		}
+		udelay(100);
+	}
+
+	/* Enable clock to ACP and wait until the clock is enabled */
+	val = acp_reg_read(acp_mmio, mmACP_CONTROL);
+	val = val | ACP_CONTROL__ClkEn_MASK;
+	acp_reg_write(val, acp_mmio, mmACP_CONTROL);
+
+	count = ACP_CLOCK_EN_TIME_OUT_VALUE;
+
+	while (true) {
+		val = acp_reg_read(acp_mmio, mmACP_STATUS);
+		if (val & (u32) 0x1)
+			break;
+		if (--count == 0) {
+			pr_err("Failed to reset ACP\n");
+			return -ETIMEDOUT;
+		}
+		udelay(100);
+	}
+
+	/* Deassert the SOFT RESET flags */
+	val = acp_reg_read(acp_mmio, mmACP_SOFT_RESET);
+	val &= ~ACP_SOFT_RESET__SoftResetAud_MASK;
+	acp_reg_write(val, acp_mmio, mmACP_SOFT_RESET);
+
+	/* initiailize Onion control DAGB register */
+	acp_reg_write(ACP_ONION_CNTL_DEFAULT, acp_mmio,
+			mmACP_AXI2DAGB_ONION_CNTL);
+
+	/* initiailize Garlic control DAGB registers */
+	acp_reg_write(ACP_GARLIC_CNTL_DEFAULT, acp_mmio,
+			mmACP_AXI2DAGB_GARLIC_CNTL);
+
+	sram_pte_offset = ACP_DAGB_GRP_SRAM_BASE_ADDRESS |
+			ACP_DAGB_BASE_ADDR_GRP_1__AXI2DAGBSnoopSel_MASK |
+			ACP_DAGB_BASE_ADDR_GRP_1__AXI2DAGBTargetMemSel_MASK |
+			ACP_DAGB_BASE_ADDR_GRP_1__AXI2DAGBGrpEnable_MASK;
+	acp_reg_write(sram_pte_offset,  acp_mmio, mmACP_DAGB_BASE_ADDR_GRP_1);
+	acp_reg_write(ACP_PAGE_SIZE_4K_ENABLE, acp_mmio,
+			mmACP_DAGB_PAGE_SIZE_GRP_1);
+
+	acp_reg_write(ACP_SRAM_BASE_ADDRESS, acp_mmio,
+			mmACP_DMA_DESC_BASE_ADDR);
+
+	/* Num of descriptiors in SRAM 0x4, means 256 descriptors;(64 * 4) */
+	acp_reg_write(0x4, acp_mmio, mmACP_DMA_DESC_MAX_NUM_DSCR);
+	acp_reg_write(ACP_EXTERNAL_INTR_CNTL__DMAIOCMask_MASK,
+		acp_mmio, mmACP_EXTERNAL_INTR_CNTL);
+
+	return 0;
+}
+
+/* Deintialize ACP */
+static int acp_deinit(void __iomem *acp_mmio)
+{
+	u32 val;
+	u32 count;
+
+	/* Assert Soft reset of ACP */
+	val = acp_reg_read(acp_mmio, mmACP_SOFT_RESET);
+
+	val |= ACP_SOFT_RESET__SoftResetAud_MASK;
+	acp_reg_write(val, acp_mmio, mmACP_SOFT_RESET);
+
+	count = ACP_SOFT_RESET_DONE_TIME_OUT_VALUE;
+	while (true) {
+		val = acp_reg_read(acp_mmio, mmACP_SOFT_RESET);
+		if (ACP_SOFT_RESET__SoftResetAudDone_MASK ==
+		    (val & ACP_SOFT_RESET__SoftResetAudDone_MASK))
+			break;
+		if (--count == 0) {
+			pr_err("Failed to reset ACP\n");
+			return -ETIMEDOUT;
+		}
+		udelay(100);
+	}
+	/** Disable ACP clock */
+	val = acp_reg_read(acp_mmio, mmACP_CONTROL);
+	val &= ~ACP_CONTROL__ClkEn_MASK;
+	acp_reg_write(val, acp_mmio, mmACP_CONTROL);
+
+	count = ACP_CLOCK_EN_TIME_OUT_VALUE;
+
+	while (true) {
+		val = acp_reg_read(acp_mmio, mmACP_STATUS);
+		if (!(val & (u32) 0x1))
+			break;
+		if (--count == 0) {
+			pr_err("Failed to reset ACP\n");
+			return -ETIMEDOUT;
+		}
+		udelay(100);
+	}
+	return 0;
+}
+
+/* ACP DMA irq handler routine for playback, capture usecases */
+static irqreturn_t dma_irq_handler(int irq, void *arg)
+{
+	u16 dscr_idx;
+	u32 intr_flag, ext_intr_status;
+	struct audio_drv_data *irq_data;
+	void __iomem *acp_mmio;
+	struct device *dev = arg;
+	bool valid_irq = false;
+
+	irq_data = dev_get_drvdata(dev);
+	acp_mmio = irq_data->acp_mmio;
+
+	ext_intr_status = acp_reg_read(acp_mmio, mmACP_EXTERNAL_INTR_STAT);
+	intr_flag = (((ext_intr_status &
+		      ACP_EXTERNAL_INTR_STAT__DMAIOCStat_MASK) >>
+		     ACP_EXTERNAL_INTR_STAT__DMAIOCStat__SHIFT));
+
+	if ((intr_flag & BIT(ACP_TO_I2S_DMA_CH_NUM)) != 0) {
+		valid_irq = true;
+		if (acp_reg_read(acp_mmio, mmACP_DMA_CUR_DSCR_13) ==
+				PLAYBACK_START_DMA_DESCR_CH13)
+			dscr_idx = PLAYBACK_START_DMA_DESCR_CH12;
+		else
+			dscr_idx = PLAYBACK_END_DMA_DESCR_CH12;
+		config_acp_dma_channel(acp_mmio, SYSRAM_TO_ACP_CH_NUM, dscr_idx,
+				       1, 0);
+		acp_dma_start(acp_mmio, SYSRAM_TO_ACP_CH_NUM, false);
+
+		snd_pcm_period_elapsed(irq_data->play_stream);
+
+		acp_reg_write((intr_flag & BIT(ACP_TO_I2S_DMA_CH_NUM)) << 16,
+				acp_mmio, mmACP_EXTERNAL_INTR_STAT);
+	}
+
+	if ((intr_flag & BIT(I2S_TO_ACP_DMA_CH_NUM)) != 0) {
+		valid_irq = true;
+		if (acp_reg_read(acp_mmio, mmACP_DMA_CUR_DSCR_15) ==
+				CAPTURE_START_DMA_DESCR_CH15)
+			dscr_idx = CAPTURE_END_DMA_DESCR_CH14;
+		else
+			dscr_idx = CAPTURE_START_DMA_DESCR_CH14;
+		config_acp_dma_channel(acp_mmio, ACP_TO_SYSRAM_CH_NUM, dscr_idx,
+				       1, 0);
+		acp_dma_start(acp_mmio, ACP_TO_SYSRAM_CH_NUM, false);
+
+		acp_reg_write((intr_flag & BIT(I2S_TO_ACP_DMA_CH_NUM)) << 16,
+				acp_mmio, mmACP_EXTERNAL_INTR_STAT);
+	}
+
+	if ((intr_flag & BIT(ACP_TO_SYSRAM_CH_NUM)) != 0) {
+		valid_irq = true;
+		snd_pcm_period_elapsed(irq_data->capture_stream);
+		acp_reg_write((intr_flag & BIT(ACP_TO_SYSRAM_CH_NUM)) << 16,
+				acp_mmio, mmACP_EXTERNAL_INTR_STAT);
+	}
+
+	if (valid_irq)
+		return IRQ_HANDLED;
+	else
+		return IRQ_NONE;
+}
+
+static int acp_dma_open(struct snd_pcm_substream *substream)
+{
+	int ret = 0;
+	struct snd_pcm_runtime *runtime = substream->runtime;
+	struct snd_soc_pcm_runtime *prtd = substream->private_data;
+	struct audio_drv_data *intr_data = dev_get_drvdata(prtd->platform->dev);
+
+	struct audio_substream_data *adata =
+		kzalloc(sizeof(struct audio_substream_data), GFP_KERNEL);
+	if (adata == NULL)
+		return -ENOMEM;
+
+	if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK)
+		runtime->hw = acp_pcm_hardware_playback;
+	else
+		runtime->hw = acp_pcm_hardware_capture;
+
+	ret = snd_pcm_hw_constraint_integer(runtime,
+					    SNDRV_PCM_HW_PARAM_PERIODS);
+	if (ret < 0) {
+		dev_err(prtd->platform->dev, "set integer constraint failed\n");
+		return ret;
+	}
+
+	adata->acp_mmio = intr_data->acp_mmio;
+	runtime->private_data = adata;
+
+	/* Enable ACP irq, when neither playback or capture streams are
+	 * active by the time when a new stream is being opened.
+	 * This enablement is not required for another stream, if current
+	 * stream is not closed
+	*/
+	if (!intr_data->play_stream && !intr_data->capture_stream)
+		acp_reg_write(1, adata->acp_mmio, mmACP_EXTERNAL_INTR_ENB);
+
+	if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK)
+		intr_data->play_stream = substream;
+	else
+		intr_data->capture_stream = substream;
+
+	return 0;
+}
+
+static int acp_dma_hw_params(struct snd_pcm_substream *substream,
+			     struct snd_pcm_hw_params *params)
+{
+	int status;
+	uint64_t size;
+	struct snd_dma_buffer *dma_buffer;
+	struct page *pg;
+	struct snd_pcm_runtime *runtime;
+	struct audio_substream_data *rtd;
+
+	dma_buffer = &substream->dma_buffer;
+
+	runtime = substream->runtime;
+	rtd = runtime->private_data;
+
+	if (WARN_ON(!rtd))
+		return -EINVAL;
+
+	size = params_buffer_bytes(params);
+	status = snd_pcm_lib_malloc_pages(substream, size);
+	if (status < 0)
+		return status;
+
+	memset(substream->runtime->dma_area, 0, params_buffer_bytes(params));
+	pg = virt_to_page(substream->dma_buffer.area);
+
+	if (pg != NULL) {
+		/* Save for runtime private data */
+		rtd->pg = pg;
+		rtd->order = get_order(size);
+
+		/* Fill the page table entries in ACP SRAM */
+		rtd->pg = pg;
+		rtd->size = size;
+		rtd->num_of_pages = PAGE_ALIGN(size) >> PAGE_SHIFT;
+		rtd->direction = substream->stream;
+
+		config_acp_dma(rtd->acp_mmio, rtd);
+		status = 0;
+	} else {
+		status = -ENOMEM;
+	}
+	return status;
+}
+
+static int acp_dma_hw_free(struct snd_pcm_substream *substream)
+{
+	return snd_pcm_lib_free_pages(substream);
+}
+
+static snd_pcm_uframes_t acp_dma_pointer(struct snd_pcm_substream *substream)
+{
+	u16 dscr;
+	u32 mul, dma_config, period_bytes;
+	u32 pos = 0;
+
+	struct snd_pcm_runtime *runtime = substream->runtime;
+	struct audio_substream_data *rtd = runtime->private_data;
+
+	period_bytes = frames_to_bytes(runtime, runtime->period_size);
+	if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK) {
+		dscr = acp_reg_read(rtd->acp_mmio, mmACP_DMA_CUR_DSCR_13);
+
+		if (dscr == PLAYBACK_START_DMA_DESCR_CH13)
+			mul = 0;
+		else
+			mul = 1;
+		pos =  (mul * period_bytes);
+	} else {
+		dma_config = acp_reg_read(rtd->acp_mmio, mmACP_DMA_CNTL_14);
+		if (dma_config != 0) {
+			dscr = acp_reg_read(rtd->acp_mmio,
+						mmACP_DMA_CUR_DSCR_14);
+			if (dscr == CAPTURE_START_DMA_DESCR_CH14)
+				mul = 1;
+			else
+				mul = 2;
+			pos = (mul * period_bytes);
+		}
+
+		if (pos >= (2 * period_bytes))
+			pos = 0;
+
+	}
+	return bytes_to_frames(runtime, pos);
+}
+
+static int acp_dma_mmap(struct snd_pcm_substream *substream,
+			struct vm_area_struct *vma)
+{
+	return snd_pcm_lib_default_mmap(substream, vma);
+}
+
+static int acp_dma_prepare(struct snd_pcm_substream *substream)
+{
+	struct snd_pcm_runtime *runtime = substream->runtime;
+	struct audio_substream_data *rtd = runtime->private_data;
+
+	if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK) {
+		config_acp_dma_channel(rtd->acp_mmio, SYSRAM_TO_ACP_CH_NUM,
+					PLAYBACK_START_DMA_DESCR_CH12,
+					NUM_DSCRS_PER_CHANNEL, 0);
+		config_acp_dma_channel(rtd->acp_mmio, ACP_TO_I2S_DMA_CH_NUM,
+					PLAYBACK_START_DMA_DESCR_CH13,
+					NUM_DSCRS_PER_CHANNEL, 0);
+		/* Fill ACP SRAM (2 periods) with zeros from System RAM
+		 * which is zero-ed in hw_params
+		*/
+		acp_dma_start(rtd->acp_mmio, SYSRAM_TO_ACP_CH_NUM, false);
+
+		/* ACP SRAM (2 periods of buffer size) is intially filled with
+		 * zeros. Before rendering starts, 2nd half of SRAM will be
+		 * filled with valid audio data DMA'ed from first half of system
+		 * RAM and 1st half of SRAM will be filled with Zeros. This is
+		 * the initial scenario when redering starts from SRAM. Later
+		 * on, 2nd half of system memory will be DMA'ed to 1st half of
+		 * SRAM, 1st half of system memory will be DMA'ed to 2nd half of
+		 * SRAM in ping-pong way till rendering stops.
+		*/
+		config_acp_dma_channel(rtd->acp_mmio, SYSRAM_TO_ACP_CH_NUM,
+					PLAYBACK_START_DMA_DESCR_CH12,
+					1, 0);
+	} else {
+		config_acp_dma_channel(rtd->acp_mmio, ACP_TO_SYSRAM_CH_NUM,
+					CAPTURE_START_DMA_DESCR_CH14,
+					NUM_DSCRS_PER_CHANNEL, 0);
+		config_acp_dma_channel(rtd->acp_mmio, I2S_TO_ACP_DMA_CH_NUM,
+					CAPTURE_START_DMA_DESCR_CH15,
+					NUM_DSCRS_PER_CHANNEL, 0);
+	}
+	return 0;
+}
+
+static int acp_dma_trigger(struct snd_pcm_substream *substream, int cmd)
+{
+	int ret;
+	u32 loops = 1000;
+
+	struct snd_pcm_runtime *runtime = substream->runtime;
+	struct snd_soc_pcm_runtime *prtd = substream->private_data;
+	struct audio_substream_data *rtd = runtime->private_data;
+
+	if (!rtd)
+		return -EINVAL;
+	switch (cmd) {
+	case SNDRV_PCM_TRIGGER_START:
+	case SNDRV_PCM_TRIGGER_PAUSE_RELEASE:
+	case SNDRV_PCM_TRIGGER_RESUME:
+		if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK) {
+			acp_dma_start(rtd->acp_mmio,
+						SYSRAM_TO_ACP_CH_NUM, false);
+			while (acp_reg_read(rtd->acp_mmio, mmACP_DMA_CH_STS) &
+						BIT(SYSRAM_TO_ACP_CH_NUM)) {
+				if (!loops--) {
+					dev_err(prtd->platform->dev,
+						"acp dma start timeout\n");
+					return -ETIMEDOUT;
+				}
+				cpu_relax();
+			}
+
+			acp_dma_start(rtd->acp_mmio,
+					ACP_TO_I2S_DMA_CH_NUM, true);
+
+		} else {
+			acp_dma_start(rtd->acp_mmio,
+					    I2S_TO_ACP_DMA_CH_NUM, true);
+		}
+		ret = 0;
+		break;
+	case SNDRV_PCM_TRIGGER_STOP:
+	case SNDRV_PCM_TRIGGER_PAUSE_PUSH:
+	case SNDRV_PCM_TRIGGER_SUSPEND:
+		/* Need to stop only circular DMA channels :
+		 * ACP_TO_I2S_DMA_CH_NUM / I2S_TO_ACP_DMA_CH_NUM. Non-circular
+		 * channels will stopped automatically after its transfer
+		 * completes : SYSRAM_TO_ACP_CH_NUM / ACP_TO_SYSRAM_CH_NUM
+		 */
+		if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK)
+			ret = acp_dma_stop(rtd->acp_mmio,
+					ACP_TO_I2S_DMA_CH_NUM);
+		else
+			ret = acp_dma_stop(rtd->acp_mmio,
+					I2S_TO_ACP_DMA_CH_NUM);
+		break;
+	default:
+		ret = -EINVAL;
+
+	}
+	return ret;
+}
+
+static int acp_dma_new(struct snd_soc_pcm_runtime *rtd)
+{
+	return snd_pcm_lib_preallocate_pages_for_all(rtd->pcm,
+							SNDRV_DMA_TYPE_DEV,
+							NULL, MIN_BUFFER,
+							MAX_BUFFER);
+}
+
+static int acp_dma_close(struct snd_pcm_substream *substream)
+{
+	struct snd_pcm_runtime *runtime = substream->runtime;
+	struct audio_substream_data *rtd = runtime->private_data;
+	struct snd_soc_pcm_runtime *prtd = substream->private_data;
+	struct audio_drv_data *adata = dev_get_drvdata(prtd->platform->dev);
+
+	kfree(rtd);
+
+	if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK)
+		adata->play_stream = NULL;
+	else
+		adata->capture_stream = NULL;
+
+	/* Disable ACP irq, when the current stream is being closed and
+	 * another stream is also not active.
+	*/
+	if (!adata->play_stream && !adata->capture_stream)
+		acp_reg_write(0, adata->acp_mmio, mmACP_EXTERNAL_INTR_ENB);
+
+	return 0;
+}
+
+static struct snd_pcm_ops acp_dma_ops = {
+	.open = acp_dma_open,
+	.close = acp_dma_close,
+	.ioctl = snd_pcm_lib_ioctl,
+	.hw_params = acp_dma_hw_params,
+	.hw_free = acp_dma_hw_free,
+	.trigger = acp_dma_trigger,
+	.pointer = acp_dma_pointer,
+	.mmap = acp_dma_mmap,
+	.prepare = acp_dma_prepare,
+};
+
+static struct snd_soc_platform_driver acp_asoc_platform = {
+	.ops = &acp_dma_ops,
+	.pcm_new = acp_dma_new,
+};
+
+static int acp_audio_probe(struct platform_device *pdev)
+{
+	int status;
+	struct audio_drv_data *audio_drv_data;
+	struct resource *res;
+
+	audio_drv_data = devm_kzalloc(&pdev->dev, sizeof(struct audio_drv_data),
+					GFP_KERNEL);
+	if (audio_drv_data == NULL)
+		return -ENOMEM;
+
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	audio_drv_data->acp_mmio = devm_ioremap_resource(&pdev->dev, res);
+
+	/* The following members gets populated in device 'open'
+	 * function. Till then interrupts are disabled in 'acp_init'
+	 * and device doesn't generate any interrupts.
+	 */
+
+	audio_drv_data->play_stream = NULL;
+	audio_drv_data->capture_stream = NULL;
+
+	res = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
+	if (!res) {
+		dev_err(&pdev->dev, "IORESOURCE_IRQ FAILED\n");
+		return -ENODEV;
+	}
+
+	status = devm_request_irq(&pdev->dev, res->start, dma_irq_handler,
+					0, "ACP_IRQ", &pdev->dev);
+	if (status) {
+		dev_err(&pdev->dev, "ACP IRQ request failed\n");
+		return status;
+	}
+
+	dev_set_drvdata(&pdev->dev, audio_drv_data);
+
+	/* Initialize the ACP */
+	acp_init(audio_drv_data->acp_mmio);
+
+	status = snd_soc_register_platform(&pdev->dev, &acp_asoc_platform);
+	if (status != 0) {
+		dev_err(&pdev->dev, "Fail to register ALSA platform device\n");
+		return status;
+	}
+
+	return status;
+}
+
+static int acp_audio_remove(struct platform_device *pdev)
+{
+	struct audio_drv_data *adata = dev_get_drvdata(&pdev->dev);
+
+	acp_deinit(adata->acp_mmio);
+	snd_soc_unregister_platform(&pdev->dev);
+
+	return 0;
+}
+
+static struct platform_driver acp_dma_driver = {
+	.probe = acp_audio_probe,
+	.remove = acp_audio_remove,
+	.driver = {
+		.name = "acp_audio_dma",
+	},
+};
+
+module_platform_driver(acp_dma_driver);
+
+MODULE_AUTHOR("[e-mail]");
+MODULE_DESCRIPTION("AMD ACP PCM Driver");
+MODULE_LICENSE("GPL v2");
+MODULE_ALIAS("platform:acp-dma-audio");

sound/soc/amd/acp.h

···
+#ifndef __ACP_HW_H
+#define __ACP_HW_H
+
+#include "include/acp_2_2_d.h"
+#include "include/acp_2_2_sh_mask.h"
+
+#define ACP_PAGE_SIZE_4K_ENABLE			0x02
+
+#define ACP_PLAYBACK_PTE_OFFSET			10
+#define ACP_CAPTURE_PTE_OFFSET			0
+
+#define ACP_GARLIC_CNTL_DEFAULT			0x00000FB4
+#define ACP_ONION_CNTL_DEFAULT			0x00000FB4
+
+#define ACP_PHYSICAL_BASE			0x14000
+
+/* Playback SRAM address (as a destination in dma descriptor) */
+#define ACP_SHARED_RAM_BANK_1_ADDRESS		0x4002000
+
+/* Capture SRAM address (as a source in dma descriptor) */
+#define ACP_SHARED_RAM_BANK_5_ADDRESS		0x400A000
+
+#define ACP_DMA_RESET_TIME			10000
+#define ACP_CLOCK_EN_TIME_OUT_VALUE		0x000000FF
+#define ACP_SOFT_RESET_DONE_TIME_OUT_VALUE	0x000000FF
+#define ACP_DMA_COMPLETE_TIME_OUT_VALUE		0x000000FF
+
+#define ACP_SRAM_BASE_ADDRESS			0x4000000
+#define ACP_DAGB_GRP_SRAM_BASE_ADDRESS		0x4001000
+#define ACP_DAGB_GRP_SRBM_SRAM_BASE_OFFSET	0x1000
+#define ACP_INTERNAL_APERTURE_WINDOW_0_ADDRESS	0x00000000
+#define ACP_INTERNAL_APERTURE_WINDOW_4_ADDRESS	0x01800000
+
+#define TO_ACP_I2S_1   0x2
+#define TO_ACP_I2S_2   0x4
+#define FROM_ACP_I2S_1 0xa
+#define FROM_ACP_I2S_2 0xb
+
+#define ACP_TILE_ON_MASK                0x03
+#define ACP_TILE_OFF_MASK               0x02
+#define ACP_TILE_ON_RETAIN_REG_MASK     0x1f
+#define ACP_TILE_OFF_RETAIN_REG_MASK    0x20
+
+#define ACP_TILE_P1_MASK                0x3e
+#define ACP_TILE_P2_MASK                0x3d
+#define ACP_TILE_DSP0_MASK              0x3b
+#define ACP_TILE_DSP1_MASK              0x37
+
+#define ACP_TILE_DSP2_MASK              0x2f
+/* Playback DMA channels */
+#define SYSRAM_TO_ACP_CH_NUM 12
+#define ACP_TO_I2S_DMA_CH_NUM 13
+
+/* Capture DMA channels */
+#define ACP_TO_SYSRAM_CH_NUM 14
+#define I2S_TO_ACP_DMA_CH_NUM 15
+
+#define NUM_DSCRS_PER_CHANNEL 2
+
+#define PLAYBACK_START_DMA_DESCR_CH12 0
+#define PLAYBACK_END_DMA_DESCR_CH12 1
+#define PLAYBACK_START_DMA_DESCR_CH13 2
+#define PLAYBACK_END_DMA_DESCR_CH13 3
+
+#define CAPTURE_START_DMA_DESCR_CH14 4
+#define CAPTURE_END_DMA_DESCR_CH14 5
+#define CAPTURE_START_DMA_DESCR_CH15 6
+#define CAPTURE_END_DMA_DESCR_CH15 7
+
+enum acp_dma_priority_level {
+	/* 0x0 Specifies the DMA channel is given normal priority */
+	ACP_DMA_PRIORITY_LEVEL_NORMAL = 0x0,
+	/* 0x1 Specifies the DMA channel is given high priority */
+	ACP_DMA_PRIORITY_LEVEL_HIGH = 0x1,
+	ACP_DMA_PRIORITY_LEVEL_FORCESIZE = 0xFF
+};
+
+struct audio_substream_data {
+	struct page *pg;
+	unsigned int order;
+	u16 num_of_pages;
+	u16 direction;
+	uint64_t size;
+	void __iomem *acp_mmio;
+};
+
+enum {
+	ACP_TILE_P1 = 0,
+	ACP_TILE_P2,
+	ACP_TILE_DSP0,
+	ACP_TILE_DSP1,
+	ACP_TILE_DSP2,
+};
+
+enum {
+	ACP_DMA_ATTRIBUTES_SHAREDMEM_TO_DAGB_ONION = 0x0,
+	ACP_DMA_ATTRIBUTES_SHARED_MEM_TO_DAGB_GARLIC = 0x1,
+	ACP_DMA_ATTRIBUTES_DAGB_ONION_TO_SHAREDMEM = 0x8,
+	ACP_DMA_ATTRIBUTES_DAGB_GARLIC_TO_SHAREDMEM = 0x9,
+	ACP_DMA_ATTRIBUTES_FORCE_SIZE = 0xF
+};
+
+typedef struct acp_dma_dscr_transfer {
+	/* Specifies the source memory location for the DMA data transfer. */
+	u32 src;
+	/* Specifies the destination memory location to where the data will
+	 * be transferred.
+	*/
+	u32 dest;
+	/* Specifies the number of bytes need to be transferred
+	* from source to destination memory.Transfer direction & IOC enable
+	*/
+	u32 xfer_val;
+	/* Reserved for future use */
+	u32 reserved;
+} acp_dma_dscr_transfer_t;
+
+#endif /*__ACP_HW_H */