From c761b58306b26ea78fa91488cbb04c61b35d583d Mon Sep 17 00:00:00 2001
From: Jie Yang <yang.jie@intel.com>
Date: Mon, 14 Jul 2014 17:11:11 +0800
Subject: [PATCH] ASoC: Intel: Add dummy read for SRAM block enable
Add dummy read after each block enable, to workaround
SRAM write missing bytes issue.
Signed-off-by: Jie Yang <yang.jie@intel.com>
Signed-off-by: Mark Brown <broonie@linaro.org>
---
sound/soc/intel/sst-haswell-dsp.c | 13 +++++++++++++
1 file changed, 13 insertions(+)
diff --git a/sound/soc/intel/sst-haswell-dsp.c b/sound/soc/intel/sst-haswell-dsp.c
index 535f517629fd..a33b931181dc 100644
--- a/sound/soc/intel/sst-haswell-dsp.c
+++ b/sound/soc/intel/sst-haswell-dsp.c
@@ -359,6 +359,17 @@ static u32 hsw_block_get_bit(struct sst_mem_block *block)
return bit;
}
+/*dummy read a SRAM block.*/
+static void sst_mem_block_dummy_read(struct sst_mem_block *block)
+{
+ u32 size;
+ u8 tmp_buf[4];
+ struct sst_dsp *sst = block->dsp;
+
+ size = block->size > 4 ? 4 : block->size;
+ memcpy_fromio(tmp_buf, sst->addr.lpe + block->offset, size);
+}
+
/* enable 32kB memory block - locks held by caller */
static int hsw_block_enable(struct sst_mem_block *block)
{
@@ -378,6 +389,8 @@ static int hsw_block_enable(struct sst_mem_block *block)
/* wait 18 DSP clock ticks */
udelay(10);
+ /*add a dummy read before the SRAM block is written, otherwise the writing may miss bytes sometimes.*/
+ sst_mem_block_dummy_read(block);
return 0;
}
--
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