linux-kernel - [RFC PATCH 2/6] ASoC: Intel: Skylake: stop init/probe if DSP is not present

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Date:   Tue, 20 Nov 2018 15:36:40 -0600
From:   Pierre-Louis Bossart <pierre-louis.bossart@...ux.intel.com>
To:     alsa-devel@...a-project.org
Cc:     tiwai@...e.de, broonie@...nel.org, vkoul@...nel.org,
        liam.r.girdwood@...ux.intel.com, andriy.shevchenko@...ux.intel.com,
        arnd@...db.de, linux-kernel@...r.kernel.org,
        Pierre-Louis Bossart <pierre-louis.bossart@...ux.intel.com>
Subject: [RFC PATCH 2/6] ASoC: Intel: Skylake: stop init/probe if DSP is not present

Check immediately if the DSP can be found, bail and avoid doing inits
to enable legacy fallback without delay.

Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@...ux.intel.com>
---
 sound/soc/intel/skylake/skl.c | 26 +++++++++++++++++---------
 1 file changed, 17 insertions(+), 9 deletions(-)

diff --git a/sound/soc/intel/skylake/skl.c b/sound/soc/intel/skylake/skl.c
index df36b8fe6d5e..1d7146773d19 100644
--- a/sound/soc/intel/skylake/skl.c
+++ b/sound/soc/intel/skylake/skl.c
@@ -931,6 +931,12 @@ static int skl_first_init(struct hdac_bus *bus)
 
 	snd_hdac_bus_parse_capabilities(bus);
 
+	/* check if dsp is there */
+	if (!bus->ppcap) {
+		dev_err(bus->dev, "bus ppcap not set, DSP not present?\n");
+		return -ENODEV;
+	}
+
 	if (skl_acquire_irq(bus, 0) < 0)
 		return -EBUSY;
 
@@ -940,23 +946,25 @@ static int skl_first_init(struct hdac_bus *bus)
 	gcap = snd_hdac_chip_readw(bus, GCAP);
 	dev_dbg(bus->dev, "chipset global capabilities = 0x%x\n", gcap);
 
-	/* allow 64bit DMA address if supported by H/W */
-	if (!dma_set_mask(bus->dev, DMA_BIT_MASK(64))) {
-		dma_set_coherent_mask(bus->dev, DMA_BIT_MASK(64));
-	} else {
-		dma_set_mask(bus->dev, DMA_BIT_MASK(32));
-		dma_set_coherent_mask(bus->dev, DMA_BIT_MASK(32));
-	}
-
 	/* read number of streams from GCAP register */
 	cp_streams = (gcap >> 8) & 0x0f;
 	pb_streams = (gcap >> 12) & 0x0f;
 
-	if (!pb_streams && !cp_streams)
+	if (!pb_streams && !cp_streams) {
+		dev_err(bus->dev, "no streams found in GCAP definitions?\n");
 		return -EIO;
+	}
 
 	bus->num_streams = cp_streams + pb_streams;
 
+	/* allow 64bit DMA address if supported by H/W */
+	if (!dma_set_mask(bus->dev, DMA_BIT_MASK(64))) {
+		dma_set_coherent_mask(bus->dev, DMA_BIT_MASK(64));
+	} else {
+		dma_set_mask(bus->dev, DMA_BIT_MASK(32));
+		dma_set_coherent_mask(bus->dev, DMA_BIT_MASK(32));
+	}
+
 	/* initialize streams */
 	snd_hdac_ext_stream_init_all
 		(bus, 0, cp_streams, SNDRV_PCM_STREAM_CAPTURE);
-- 
2.17.1