git.openwrt.org Git - openwrt/staging/hauke.git/blob

   1 From 3b671c297cff1ba5f5c3e089ffa82523eca3c598 Mon Sep 17 00:00:00 2001
   2 From: Mihai Serban <mihai.serban@nxp.com>
   3 Date: Fri, 7 Jul 2017 15:09:51 +0300
   4 Subject: [PATCH] MLK-15927-1: ASoC: fsl_sai: Fix noise when using EDMA
   5
   6 EDMA requires the period size to be multiple of maxburst. Otherwise the
   7 remaining bytes are not transferred and thus noise is produced.
   8
   9 We can handle this issue by adding a constraint on
  10 SNDRV_PCM_HW_PARAM_PERIOD_SIZE to be multiple of tx/rx maxburst value.
  11
  12 This is based on a similar patch we have for ESAI:
  13 commit bd3f3eb2a37c
  14 ("MLK-15109-2: ASoC: fsl_esai: add constrain_period_size")
  15
  16 Signed-off-by: Mihai Serban <mihai.serban@nxp.com>
  17 Reviewed-by: Shengjiu Wang <shengjiu.wang@nxp.com>
  18 ---
  19  sound/soc/fsl/fsl_sai.c | 23 +++++++++++++++++++++++
  20  sound/soc/fsl/fsl_sai.h |  2 ++
  21  2 files changed, 25 insertions(+)
  22
  23 --- a/sound/soc/fsl/fsl_sai.c
  24 +++ b/sound/soc/fsl/fsl_sai.c
  25 @@ -35,6 +35,7 @@ static struct fsl_sai_soc_data fsl_sai_v
  26         .fifos = 1,
  27         .fifo_depth = 32,
  28         .flags = 0,
  29 +       .constrain_period_size = false,
  30  };
  31
  32  static struct fsl_sai_soc_data fsl_sai_imx6sx = {
  33 @@ -44,6 +45,7 @@ static struct fsl_sai_soc_data fsl_sai_i
  34         .fifo_depth = 32,
  35         .flags = 0,
  36         .reg_offset = 0,
  37 +       .constrain_period_size = false,
  38  };
  39
  40  static struct fsl_sai_soc_data fsl_sai_imx6ul = {
  41 @@ -53,6 +55,7 @@ static struct fsl_sai_soc_data fsl_sai_i
  42         .fifo_depth = 32,
  43         .flags = 0,
  44         .reg_offset = 0,
  45 +       .constrain_period_size = false,
  46  };
  47
  48  static struct fsl_sai_soc_data fsl_sai_imx7ulp = {
  49 @@ -62,6 +65,7 @@ static struct fsl_sai_soc_data fsl_sai_i
  50         .fifo_depth = 16,
  51         .flags = SAI_FLAG_PMQOS,
  52         .reg_offset = 0,
  53 +       .constrain_period_size = false,
  54  };
  55
  56  static struct fsl_sai_soc_data fsl_sai_imx8mq = {
  57 @@ -71,6 +75,17 @@ static struct fsl_sai_soc_data fsl_sai_i
  58         .fifo_depth = 32,
  59         .flags = 0,
  60         .reg_offset = 8,
  61 +       .constrain_period_size = false,
  62 +};
  63 +
  64 +static struct fsl_sai_soc_data fsl_sai_imx8qm = {
  65 +       .imx = true,
  66 +       .dataline = 0x3,
  67 +       .fifos = 1,
  68 +       .fifo_depth = 32,
  69 +       .flags = 0,
  70 +       .reg_offset = 0,
  71 +       .constrain_period_size = true,
  72  };
  73
  74  static const unsigned int fsl_sai_rates[] = {
  75 @@ -692,6 +707,13 @@ static int fsl_sai_startup(struct snd_pc
  76                            FSL_SAI_CR3_TRCE_MASK,
  77                            FSL_SAI_CR3_TRCE(sai->dataline[tx]));
  78
  79 +       /* EDMA engine needs periods of size multiple of tx/rx maxburst */
  80 +       if (sai->soc->constrain_period_size)
  81 +               snd_pcm_hw_constraint_step(substream->runtime, 0,
  82 +                                          SNDRV_PCM_HW_PARAM_PERIOD_SIZE,
  83 +                                          tx ? sai->dma_params_tx.maxburst :
  84 +                                          sai->dma_params_rx.maxburst);
  85 +
  86         ret = snd_pcm_hw_constraint_list(substream->runtime, 0,
  87                         SNDRV_PCM_HW_PARAM_RATE, &fsl_sai_rate_constraints);
  88
  89 @@ -914,6 +936,7 @@ static const struct of_device_id fsl_sai
  90         { .compatible = "fsl,imx6ul-sai", .data = &fsl_sai_imx6ul },
  91         { .compatible = "fsl,imx7ulp-sai", .data = &fsl_sai_imx7ulp },
  92         { .compatible = "fsl,imx8mq-sai", .data = &fsl_sai_imx8mq },
  93 +       { .compatible = "fsl,imx8qm-sai", .data = &fsl_sai_imx8qm },
  94         { /* sentinel */ }
  95  };
  96  MODULE_DEVICE_TABLE(of, fsl_sai_ids);
  97 --- a/sound/soc/fsl/fsl_sai.h
  98 +++ b/sound/soc/fsl/fsl_sai.h
  99 @@ -147,6 +147,8 @@ struct fsl_sai_soc_data {
 100         unsigned int flags;
 101         unsigned char reg_offset;
 102         bool imx;
 103 +       /* True for EDMA because it needs period size multiple of maxburst */
 104 +       bool constrain_period_size;
 105  };
 106
 107  struct fsl_sai {