Quelle  loongson_dma.c   Sprache: C

// SPDX-License-Identifier: GPL-2.0
//
// Loongson ALSA SoC Platform (DMA) driver
//
// Copyright (C) 2023 Loongson Technology Corporation Limited
// Author: Yingkun Meng <mengyingkun@loongson.cn>
//

#include <linux/module.h>
#include <linux/io-64-nonatomic-lo-hi.h>
#include <linux/delay.h>
#include <linux/pm_runtime.h>
#include <linux/dma-mapping.h>
#include <sound/soc.h>
#include <sound/pcm.h>
#include <sound/pcm_params.h>
#include "loongson_i2s.h"

/* DMA dma_order Register */
#define DMA_ORDER_STOP          BIT(4) /* DMA stop */
#define DMA_ORDER_START         BIT(3) /* DMA start */
#define DMA_ORDER_ASK_VALID     BIT(2) /* DMA ask valid flag */
#define DMA_ORDER_AXI_UNCO      BIT(1) /* Uncache access */
#define DMA_ORDER_ADDR_64       BIT(0) /* 64bits address support */

#define DMA_ORDER_ASK_MASK      (~0x1fUL) /* Ask addr mask */
#define DMA_ORDER_CTRL_MASK     (0x0fUL)  /* Control mask  */

/*
 * DMA registers descriptor.
 */
struct loongson_dma_desc {
 u32 order;  /* Next descriptor address register */
 u32 saddr;  /* Source address register */
 u32 daddr;  /* Device address register */
 u32 length;  /* Total length register */
 u32 step_length; /* Memory stride register */
 u32 step_times;  /* Repeat time register */
 u32 cmd;  /* Command register */
 u32 stats;  /* Status register */
 u32 order_hi;  /* Next descriptor high address register */
 u32 saddr_hi;  /* High source address register */
 u32 res[6];  /* Reserved */
} __packed;

struct loongson_runtime_data {
 struct loongson_dma_data *dma_data;

 struct loongson_dma_desc *dma_desc_arr;
 dma_addr_t dma_desc_arr_phy;
 int dma_desc_arr_size;

 struct loongson_dma_desc *dma_pos_desc;
 dma_addr_t dma_pos_desc_phy;
};

static const struct snd_pcm_hardware ls_pcm_hardware = {
 .info = SNDRV_PCM_INFO_MMAP |
  SNDRV_PCM_INFO_INTERLEAVED |
  SNDRV_PCM_INFO_MMAP_VALID |
  SNDRV_PCM_INFO_RESUME |
  SNDRV_PCM_INFO_PAUSE,
 .formats = (SNDRV_PCM_FMTBIT_S8 |
  SNDRV_PCM_FMTBIT_S16_LE |
  SNDRV_PCM_FMTBIT_S20_3LE |
  SNDRV_PCM_FMTBIT_S24_LE),
 .period_bytes_min = 128,
 .period_bytes_max = 128 * 1024,
 .periods_min = 1,
 .periods_max = PAGE_SIZE / sizeof(struct loongson_dma_desc),
 .buffer_bytes_max = 1024 * 1024,
};

static struct
loongson_dma_desc *dma_desc_save(struct loongson_runtime_data *prtd)
{
 void __iomem *order_reg = prtd->dma_data->order_addr;
 u64 val;

 val = (u64)prtd->dma_pos_desc_phy & DMA_ORDER_ASK_MASK;
 val |= (readq(order_reg) & DMA_ORDER_CTRL_MASK);
 val |= DMA_ORDER_ASK_VALID;
 writeq(val, order_reg);

 while (readl(order_reg) & DMA_ORDER_ASK_VALID)
  udelay(2);

 return prtd->dma_pos_desc;
}

static int loongson_pcm_trigger(struct snd_soc_component *component,
    struct snd_pcm_substream *substream, int cmd)
{
 struct loongson_runtime_data *prtd = substream->runtime->private_data;
 struct device *dev = substream->pcm->card->dev;
 void __iomem *order_reg = prtd->dma_data->order_addr;
 u64 val;

 switch (cmd) {
 case SNDRV_PCM_TRIGGER_START:
 case SNDRV_PCM_TRIGGER_RESUME:
 case SNDRV_PCM_TRIGGER_PAUSE_RELEASE:
  val = prtd->dma_pos_desc_phy & DMA_ORDER_ASK_MASK;
  if (dev->coherent_dma_mask == DMA_BIT_MASK(64))
   val |= DMA_ORDER_ADDR_64;
  else
   val &= ~DMA_ORDER_ADDR_64;
  val |= (readq(order_reg) & DMA_ORDER_CTRL_MASK);
  val |= DMA_ORDER_START;
  writeq(val, order_reg);

  while ((readl(order_reg) & DMA_ORDER_START))
   udelay(2);
  break;
 case SNDRV_PCM_TRIGGER_STOP:
 case SNDRV_PCM_TRIGGER_SUSPEND:
 case SNDRV_PCM_TRIGGER_PAUSE_PUSH:
  dma_desc_save(prtd);

  /* dma stop */
  val = readq(order_reg) | DMA_ORDER_STOP;
  writeq(val, order_reg);
  udelay(1000);

  break;
 default:
  dev_err(dev, "Invalid pcm trigger operation\n");
  return -EINVAL;
 }

 return 0;
}

static int loongson_pcm_hw_params(struct snd_soc_component *component,
      struct snd_pcm_substream *substream,
      struct snd_pcm_hw_params *params)
{
 struct snd_pcm_runtime *runtime = substream->runtime;
 struct device *dev = substream->pcm->card->dev;
 struct loongson_runtime_data *prtd = runtime->private_data;
 size_t buf_len = params_buffer_bytes(params);
 size_t period_len = params_period_bytes(params);
 dma_addr_t order_addr, mem_addr;
 struct loongson_dma_desc *desc;
 u32 num_periods;
 int i;

 if (buf_len % period_len) {
  dev_err(dev, "buf len not multiply of period len\n");
  return -EINVAL;
 }

 num_periods = buf_len / period_len;
 if (!num_periods || num_periods > prtd->dma_desc_arr_size) {
  dev_err(dev, "dma data too small or too big\n");
  return -EINVAL;
 }

 snd_pcm_set_runtime_buffer(substream, &substream->dma_buffer);
 runtime->dma_bytes = buf_len;

 /* initialize dma descriptor array */
 mem_addr = runtime->dma_addr;
 order_addr = prtd->dma_desc_arr_phy;
 for (i = 0; i < num_periods; i++) {
  desc = &prtd->dma_desc_arr[i];

  /* next descriptor physical address */
  order_addr += sizeof(*desc);
  desc->order = lower_32_bits(order_addr | BIT(0));
  desc->order_hi = upper_32_bits(order_addr);

  desc->saddr = lower_32_bits(mem_addr);
  desc->saddr_hi = upper_32_bits(mem_addr);
  desc->daddr = prtd->dma_data->dev_addr;

  desc->cmd = BIT(0);
  if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK)
   desc->cmd |= BIT(12);

  desc->length = period_len >> 2;
  desc->step_length = 0;
  desc->step_times = 1;

  mem_addr += period_len;
 }
 desc = &prtd->dma_desc_arr[num_periods - 1];
 desc->order = lower_32_bits(prtd->dma_desc_arr_phy | BIT(0));
 desc->order_hi = upper_32_bits(prtd->dma_desc_arr_phy);

 /* init position descriptor */
 *prtd->dma_pos_desc = *prtd->dma_desc_arr;

 return 0;
}

static snd_pcm_uframes_t
loongson_pcm_pointer(struct snd_soc_component *component,
       struct snd_pcm_substream *substream)
{
 struct snd_pcm_runtime *runtime = substream->runtime;
 struct loongson_runtime_data *prtd = runtime->private_data;
 struct loongson_dma_desc *desc;
 snd_pcm_uframes_t x;
 u64 addr;

 desc = dma_desc_save(prtd);
 addr = ((u64)desc->saddr_hi << 32) | desc->saddr;

 x = bytes_to_frames(runtime, addr - runtime->dma_addr);
 if (x == runtime->buffer_size)
  x = 0;
 return x;
}

static irqreturn_t loongson_pcm_dma_irq(int irq, void *devid)
{
 struct snd_pcm_substream *substream = devid;

 snd_pcm_period_elapsed(substream);
 return IRQ_HANDLED;
}

static int loongson_pcm_open(struct snd_soc_component *component,
        struct snd_pcm_substream *substream)
{
 struct snd_pcm_runtime *runtime = substream->runtime;
 struct snd_soc_pcm_runtime *rtd = snd_soc_substream_to_rtd(substream);
 struct snd_card *card = substream->pcm->card;
 struct loongson_runtime_data *prtd;
 struct loongson_dma_data *dma_data;

 /*
 * For mysterious reasons (and despite what the manual says)
 * playback samples are lost if the DMA count is not a multiple
 * of the DMA burst size.  Let's add a rule to enforce that.
 */
 snd_pcm_hw_constraint_step(runtime, 0,
       SNDRV_PCM_HW_PARAM_PERIOD_BYTES, 128);
 snd_pcm_hw_constraint_step(runtime, 0,
       SNDRV_PCM_HW_PARAM_BUFFER_BYTES, 128);
 snd_pcm_hw_constraint_integer(substream->runtime,
          SNDRV_PCM_HW_PARAM_PERIODS);
 snd_soc_set_runtime_hwparams(substream, &ls_pcm_hardware);

 prtd = kzalloc(sizeof(*prtd), GFP_KERNEL);
 if (!prtd)
  return -ENOMEM;

 prtd->dma_desc_arr = dma_alloc_coherent(card->dev, PAGE_SIZE,
      &prtd->dma_desc_arr_phy,
      GFP_KERNEL);
 if (!prtd->dma_desc_arr)
  goto desc_err;

 prtd->dma_desc_arr_size = PAGE_SIZE / sizeof(*prtd->dma_desc_arr);

 prtd->dma_pos_desc = dma_alloc_coherent(card->dev,
      sizeof(*prtd->dma_pos_desc),
      &prtd->dma_pos_desc_phy,
      GFP_KERNEL);
 if (!prtd->dma_pos_desc)
  goto pos_err;

 dma_data = snd_soc_dai_get_dma_data(snd_soc_rtd_to_cpu(rtd, 0), substream);
 prtd->dma_data = dma_data;

 substream->runtime->private_data = prtd;

 return 0;
pos_err:
 dma_free_coherent(card->dev, PAGE_SIZE, prtd->dma_desc_arr,
     prtd->dma_desc_arr_phy);
desc_err:
 kfree(prtd);

 return -ENOMEM;
}

static int loongson_pcm_close(struct snd_soc_component *component,
         struct snd_pcm_substream *substream)
{
 struct snd_card *card = substream->pcm->card;
 struct loongson_runtime_data *prtd = substream->runtime->private_data;

 dma_free_coherent(card->dev, PAGE_SIZE, prtd->dma_desc_arr,
     prtd->dma_desc_arr_phy);

 dma_free_coherent(card->dev, sizeof(*prtd->dma_pos_desc),
     prtd->dma_pos_desc, prtd->dma_pos_desc_phy);

 kfree(prtd);
 return 0;
}

static int loongson_pcm_mmap(struct snd_soc_component *component,
        struct snd_pcm_substream *substream,
        struct vm_area_struct *vma)
{
 return remap_pfn_range(vma, vma->vm_start,
   substream->dma_buffer.addr >> PAGE_SHIFT,
   vma->vm_end - vma->vm_start, vma->vm_page_prot);
}

static int loongson_pcm_new(struct snd_soc_component *component,
       struct snd_soc_pcm_runtime *rtd)
{
 struct snd_card *card = rtd->card->snd_card;
 struct snd_pcm_substream *substream;
 struct loongson_dma_data *dma_data;
 unsigned int i;
 int ret;

 for_each_pcm_streams(i) {
  substream = rtd->pcm->streams[i].substream;
  if (!substream)
   continue;

  dma_data = snd_soc_dai_get_dma_data(snd_soc_rtd_to_cpu(rtd, 0),
          substream);
  ret = devm_request_irq(card->dev, dma_data->irq,
           loongson_pcm_dma_irq,
           IRQF_TRIGGER_HIGH, LS_I2S_DRVNAME,
           substream);
  if (ret < 0) {
   dev_err(card->dev, "request irq for DMA failed\n");
   return ret;
  }
 }

 return snd_pcm_set_fixed_buffer_all(rtd->pcm, SNDRV_DMA_TYPE_DEV,
         card->dev,
         ls_pcm_hardware.buffer_bytes_max);
}

const struct snd_soc_component_driver loongson_i2s_component = {
 .name  = LS_I2S_DRVNAME,
 .open  = loongson_pcm_open,
 .close  = loongson_pcm_close,
 .hw_params = loongson_pcm_hw_params,
 .trigger = loongson_pcm_trigger,
 .pointer = loongson_pcm_pointer,
 .mmap  = loongson_pcm_mmap,
 .pcm_construct = loongson_pcm_new,
};