From f911217e6edd48de4277eec2f112449d61fe710e Mon Sep 17 00:00:00 2001
From: Alison Wang <b18965@freescale.com>
Date: Mon, 29 Sep 2014 17:29:46 +0800
Subject: ls102xa: audio: Workaround for SAI data transfer endian issue

Transmit Data Register(TDR) used as the destination address
of EDMA transaction is in big-endian mode. The audio data in
memory and EDMA transaction are in little-endian mode. For
S16_LE format data, a workaround is to swap the original 16-bit
data, and then write into the higher 16 bit of TDR.

Signed-off-by: Alison Wang <alison.wang@freescale.com>
Change-Id: Ib15832743e9a4c69792f2dad4cb00fbbc1d2daaa
Reviewed-on: http://git.am.freescale.net:8181/21063
Tested-by: Review Code-CDREVIEW <CDREVIEW@freescale.com>
Reviewed-by: Jingchang Lu <jingchang.lu@freescale.com>
Reviewed-by: Zhengxiong Jin <Jason.Jin@freescale.com>

diff --git a/include/sound/pcm.h b/include/sound/pcm.h
index 84b10f9..a07b670 100644
--- a/include/sound/pcm.h
+++ b/include/sound/pcm.h
@@ -418,6 +418,8 @@ struct snd_pcm_substream {
 #endif
 	/* misc flags */
 	unsigned int hw_opened: 1;
+	/* data swapped flags */
+	unsigned int data_swapped;
 };
 
 #define SUBSTREAM_BUSY(substream) ((substream)->ref_count > 0)
diff --git a/sound/core/pcm_lib.c b/sound/core/pcm_lib.c
index a210467..f1fe6e6 100644
--- a/sound/core/pcm_lib.c
+++ b/sound/core/pcm_lib.c
@@ -1962,6 +1962,9 @@ static int snd_pcm_lib_write_transfer(struct snd_pcm_substream *substream,
 	struct snd_pcm_runtime *runtime = substream->runtime;
 	int err;
 	char __user *buf = (char __user *) data + frames_to_bytes(runtime, off);
+	int i;
+	char tmp;
+
 	if (substream->ops->copy) {
 		if ((err = substream->ops->copy(substream, -1, hwoff, buf, frames)) < 0)
 			return err;
@@ -1969,6 +1972,22 @@ static int snd_pcm_lib_write_transfer(struct snd_pcm_substream *substream,
 		char *hwbuf = runtime->dma_area + frames_to_bytes(runtime, hwoff);
 		if (copy_from_user(hwbuf, buf, frames_to_bytes(runtime, frames)))
 			return -EFAULT;
+
+		if (substream->data_swapped) {
+			switch (runtime->format) {
+			case SNDRV_PCM_FORMAT_S16_LE:
+				for (i = 0;
+				     i < frames_to_bytes(runtime, frames);
+				     i = i + 2) {
+					tmp = *(hwbuf + i);
+					*(hwbuf + i) = *(hwbuf + i + 1);
+					*(hwbuf + i + 1) = tmp;
+				}
+				break;
+			default:
+				return -EINVAL;
+			}
+		}
 	}
 	return 0;
 }
@@ -2184,11 +2203,30 @@ static int snd_pcm_lib_read_transfer(struct snd_pcm_substream *substream,
 	struct snd_pcm_runtime *runtime = substream->runtime;
 	int err;
 	char __user *buf = (char __user *) data + frames_to_bytes(runtime, off);
+	int i;
+	char tmp;
+
 	if (substream->ops->copy) {
 		if ((err = substream->ops->copy(substream, -1, hwoff, buf, frames)) < 0)
 			return err;
 	} else {
 		char *hwbuf = runtime->dma_area + frames_to_bytes(runtime, hwoff);
+		if (substream->data_swapped) {
+			switch (runtime->format) {
+			case SNDRV_PCM_FORMAT_S16_LE:
+				for (i = 0;
+				     i < frames_to_bytes(runtime, frames);
+				     i = i + 2) {
+					tmp = *(hwbuf + i);
+					*(hwbuf + i) = *(hwbuf + i + 1);
+					*(hwbuf + i + 1) = tmp;
+				}
+				break;
+			default:
+				return -EINVAL;
+			}
+		}
+
 		if (copy_to_user(buf, hwbuf, frames_to_bytes(runtime, frames)))
 			return -EFAULT;
 	}
diff --git a/sound/soc/fsl/fsl_sai.c b/sound/soc/fsl/fsl_sai.c
index 7286824..ff86daf 100644
--- a/sound/soc/fsl/fsl_sai.c
+++ b/sound/soc/fsl/fsl_sai.c
@@ -334,6 +334,9 @@ static int fsl_sai_startup(struct snd_pcm_substream *substream,
 	struct fsl_sai *sai = snd_soc_dai_get_drvdata(cpu_dai);
 	u32 reg;
 
+	if (sai->big_endian_regs)
+		substream->data_swapped = 1;
+
 	if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK)
 		reg = FSL_SAI_TCR3;
 	else
@@ -549,8 +552,14 @@ static int fsl_sai_probe(struct platform_device *pdev)
 		return PTR_ERR(sai->regmap);
 	}
 
-	sai->dma_params_rx.addr = res->start + FSL_SAI_RDR;
-	sai->dma_params_tx.addr = res->start + FSL_SAI_TDR;
+	if (sai->big_endian_regs) {
+		sai->dma_params_rx.addr = res->start + FSL_SAI_RDR + 2;
+		sai->dma_params_tx.addr = res->start + FSL_SAI_TDR + 2;
+	} else {
+		sai->dma_params_rx.addr = res->start + FSL_SAI_RDR;
+		sai->dma_params_tx.addr = res->start + FSL_SAI_TDR;
+	}
+
 	sai->dma_params_rx.maxburst = FSL_SAI_MAXBURST_RX;
 	sai->dma_params_tx.maxburst = FSL_SAI_MAXBURST_TX;
 
-- 
cgit v0.10.2