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/io.h>
#include <linux/sizes.h>
#include <linux/pm_runtime.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;
}

static void acp_set_sram_bank_state(void __iomem *acp_mmio, u16 bank,
					bool power_on)
{
	u32 val, req_reg, sts_reg, sts_reg_mask;
	u32 loops = 1000;

	if (bank < 32) {
		req_reg = mmACP_MEM_SHUT_DOWN_REQ_LO;
		sts_reg = mmACP_MEM_SHUT_DOWN_STS_LO;
		sts_reg_mask = 0xFFFFFFFF;

	} else {
		bank -= 32;
		req_reg = mmACP_MEM_SHUT_DOWN_REQ_HI;
		sts_reg = mmACP_MEM_SHUT_DOWN_STS_HI;
		sts_reg_mask = 0x0000FFFF;
	}

	val = acp_reg_read(acp_mmio, req_reg);
	if (val & (1 << bank)) {
		/* bank is in off state */
		if (power_on == true)
			/* request to on */
			val &= ~(1 << bank);
		else
			/* request to off */
			return;
	} else {
		/* bank is in on state */
		if (power_on == false)
			/* request to off */
			val |= 1 << bank;
		else
			/* request to on */
			return;
	}
	acp_reg_write(val, acp_mmio, req_reg);

	while (acp_reg_read(acp_mmio, sts_reg) != sts_reg_mask) {
		if (!loops--) {
			pr_err("ACP SRAM bank %d state change failed\n", bank);
			break;
		}
		cpu_relax();
	}
}

/* Initialize and bring ACP hardware to default state. */
static int acp_init(void __iomem *acp_mmio)
{
	u16 bank;
	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);

       /* When ACP_TILE_P1 is turned on, all SRAM banks get turned on.
	* Now, turn off all of them. This can't be done in 'poweron' of
	* ACP pm domain, as this requires ACP to be initialized.
	*/
	for (bank = 1; bank < 48; bank++)
		acp_set_sram_bank_state(acp_mmio, bank, false);

	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)
{
	u16 bank;
	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;
		for (bank = 1; bank <= 4; bank++)
			acp_set_sram_bank_state(intr_data->acp_mmio, bank,
						true);
	} else {
		intr_data->capture_stream = substream;
		for (bank = 5; bank <= 8; bank++)
			acp_set_sram_bank_state(intr_data->acp_mmio, bank,
						true);
	}

	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) {
		acp_set_sram_bank_state(rtd->acp_mmio, 0, true);
		/* 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)
{
	u16 bank;
	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;
		for (bank = 1; bank <= 4; bank++)
			acp_set_sram_bank_state(adata->acp_mmio, bank,
						false);
	} else {
		adata->capture_stream = NULL;
		for (bank = 5; bank <= 8; bank++)
			acp_set_sram_bank_state(adata->acp_mmio, bank,
						false);
	}

	/* 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;
	}

	pm_runtime_set_autosuspend_delay(&pdev->dev, 10000);
	pm_runtime_use_autosuspend(&pdev->dev);
	pm_runtime_enable(&pdev->dev);

	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);
	pm_runtime_disable(&pdev->dev);

	return 0;
}

static int acp_pcm_resume(struct device *dev)
{
	u16 bank;
	struct audio_drv_data *adata = dev_get_drvdata(dev);

	acp_init(adata->acp_mmio);

	if (adata->play_stream && adata->play_stream->runtime) {
		for (bank = 1; bank <= 4; bank++)
			acp_set_sram_bank_state(adata->acp_mmio, bank,
						true);
		config_acp_dma(adata->acp_mmio,
				adata->play_stream->runtime->private_data);
	}
	if (adata->capture_stream && adata->capture_stream->runtime) {
		for (bank = 5; bank <= 8; bank++)
			acp_set_sram_bank_state(adata->acp_mmio, bank,
						true);
		config_acp_dma(adata->acp_mmio,
				adata->capture_stream->runtime->private_data);
	}
	acp_reg_write(1, adata->acp_mmio, mmACP_EXTERNAL_INTR_ENB);
	return 0;
}

static int acp_pcm_runtime_suspend(struct device *dev)
{
	struct audio_drv_data *adata = dev_get_drvdata(dev);

	acp_deinit(adata->acp_mmio);
	acp_reg_write(0, adata->acp_mmio, mmACP_EXTERNAL_INTR_ENB);
	return 0;
}

static int acp_pcm_runtime_resume(struct device *dev)
{
	struct audio_drv_data *adata = dev_get_drvdata(dev);

	acp_init(adata->acp_mmio);
	acp_reg_write(1, adata->acp_mmio, mmACP_EXTERNAL_INTR_ENB);
	return 0;
}

static const struct dev_pm_ops acp_pm_ops = {
	.resume = acp_pcm_resume,
	.runtime_suspend = acp_pcm_runtime_suspend,
	.runtime_resume = acp_pcm_runtime_resume,
};

static struct platform_driver acp_dma_driver = {
	.probe = acp_audio_probe,
	.remove = acp_audio_remove,
	.driver = {
		.name = "acp_audio_dma",
		.pm = &acp_pm_ops,
	},
};

module_platform_driver(acp_dma_driver);

MODULE_AUTHOR("Maruthi.Bayyavarapu@amd.com");
MODULE_DESCRIPTION("AMD ACP PCM Driver");
MODULE_LICENSE("GPL v2");
MODULE_ALIAS("platform:acp-dma-audio");