ASoC: rt5677: Load firmware via SPI using delayed work

The firmware rt5677_elf_vad is an ELF binary obtained from
request_firmware(). Sections of the ELF are loaded to
the DSP via SPI. A model (e.g. en_us.mmap) can optionally be
loaded to the DSP at RT5677_MODEL_ADDR to overwrite the
baked-in model in rt5677_elf_vad.

Then we switch to DSP mode, load firmware, and let DSP run.
When a hotword is detected, an interrupt is fired and
rt5677_irq() is called. When 'DSP VAD Switch' is turned off,
the codec is set back to normal mode.

The kcontrol 'DSP VAD Switch' is automatically enabled/disabled
when the hotwording PCM stream is opened/closed.
Signed-off-by: Ben Zhang <benzh@chromium.org>
Signed-off-by: Curtis Malainey <cujomalainey@chromium.org>
Link: https://lore.kernel.org/r/20191106011335.223061-2-cujomalainey@chromium.orgSigned-off-by: Mark Brown <broonie@kernel.org>

sound/soc/codecs/rt5677-spi.c

@@ -26,6 +26,7 @@
 
 #include <sound/soc.h>
 
+#include "rt5677.h"
 #include "rt5677-spi.h"
 
 #define DRV_NAME "rt5677spi"
@@ -111,10 +112,16 @@ static int rt5677_spi_pcm_close(
 		struct snd_soc_component *component,
 		struct snd_pcm_substream *substream)
 {
+	struct snd_soc_pcm_runtime *rtd = substream->private_data;
+	struct snd_soc_component *codec_component =
+			snd_soc_rtdcom_lookup(rtd, "rt5677");
+	struct rt5677_priv *rt5677 =
+			snd_soc_component_get_drvdata(codec_component);
 	struct rt5677_dsp *rt5677_dsp =
 			snd_soc_component_get_drvdata(component);
 
 	cancel_delayed_work_sync(&rt5677_dsp->copy_work);
+	rt5677->set_dsp_vad(codec_component, false);
 	return 0;
 }
 
@@ -154,9 +161,15 @@ static int rt5677_spi_prepare(
 		struct snd_soc_component *component,
 		struct snd_pcm_substream *substream)
 {
+	struct snd_soc_pcm_runtime *rtd = substream->private_data;
+	struct snd_soc_component *rt5677_component =
+			snd_soc_rtdcom_lookup(rtd, "rt5677");
+	struct rt5677_priv *rt5677 =
+			snd_soc_component_get_drvdata(rt5677_component);
 	struct rt5677_dsp *rt5677_dsp =
 			snd_soc_component_get_drvdata(component);
 
+	rt5677->set_dsp_vad(rt5677_component, true);
 	rt5677_dsp->dma_offset = 0;
 	rt5677_dsp->avail_bytes = 0;
 	return 0;

sound/soc/codecs/rt5677.h

@@ -1730,6 +1730,7 @@ enum {
 	RT5677_AIF4,
 	RT5677_AIF5,
 	RT5677_AIFS,
+	RT5677_DSPBUFF,
 };
 
 enum {
@@ -1845,14 +1846,17 @@ struct rt5677_priv {
 #ifdef CONFIG_GPIOLIB
 	struct gpio_chip gpio_chip;
 #endif
-	bool dsp_vad_en;
+	bool dsp_vad_en; /* DSP VAD enable/disable request */
 	bool is_dsp_mode;
 	bool is_vref_slow;
+	struct delayed_work dsp_work;
 
 	/* Interrupt handling */
 	struct irq_domain *domain;
 	struct mutex irq_lock;
 	unsigned int irq_en;
+
+	int (*set_dsp_vad)(struct snd_soc_component *component, bool on);
 };
 
 int rt5677_sel_asrc_clk_src(struct snd_soc_component *component,