ASoC: intel: Fix sst-dsp dependency on dw stuff

The recent commit [a92ea59b: ASoC: Intel: sst: only select
sst-firmware when DW DMAC is built-in] introduced more strict kconfig
dependency (depends on DW_DMAC_CORE=y) for avoiding the build failures
due to dependency messes in intel-sst.  This makes, however, it
impossible to use this driver with the modularized systems,
i.e. typically on Linux distros.

The problem addressed in the commit above is that sst_dsp_new() and
sst_dsp_free() includes the firmware init / finish that call dw_*()
functions.  Thus building it as built-in with DW_DMAC_CORE module
results in the missing symbols.

However, these sst_dsp functions are basically called only from the
drivers that depend on DW_DMAC_CORE already.  That is, once when these
functions are split out, the rest can be independent from dw stuff.

This patch attempts to solve the issue by the following:
- Split sst-dsp stuff into two modules: snd-soc-sst-dsp and
  snd-soc-sst-firmware.
- Move sst_dsp_new() and sst_dsp_free() to the latter module so that
  the former module can be independent from DW_DMAC_CORE.
- Add a new kconfig SND_SOC_INTEL_SST_FIRMWARE to select the latter
  module by machine drivers.

One only remaining pitfall is that each machine driver has to select
SND_SOC_INTEL_SST_FIRMWARE carefully depending on DW_DMAC_CORE.
This can't be done cleanly due to the restriction of the current
kbuild.

Bugzilla: https://bugzilla.opensuse.org/show_bug.cgi?id=988117
Fixes: a92ea59b ('ASoC: Intel: sst: only select sst-firmware when DW DMAC is built-in')
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Mark Brown <broonie@kernel.org>

sound/soc/intel/Kconfig

@@ -32,6 +32,12 @@ config SND_SOC_INTEL_SST
 	select SND_SOC_INTEL_SST_MATCH if ACPI
 	depends on (X86 || COMPILE_TEST)
 
+# firmware stuff depends DW_DMAC_CORE; since there is no depends-on from
+# the reverse selection, each machine driver needs to select
+# SND_SOC_INTEL_SST_FIRMWARE carefully depending on DW_DMAC_CORE
+config SND_SOC_INTEL_SST_FIRMWARE
+	tristate
+
 config SND_SOC_INTEL_SST_ACPI
 	tristate
 
@@ -47,8 +53,9 @@ config SND_SOC_INTEL_BAYTRAIL
 config SND_SOC_INTEL_HASWELL_MACH
 	tristate "ASoC Audio DSP support for Intel Haswell Lynxpoint"
 	depends on X86_INTEL_LPSS && I2C && I2C_DESIGNWARE_PLATFORM
-	depends on DW_DMAC_CORE=y
+	depends on DW_DMAC_CORE
 	select SND_SOC_INTEL_SST
+	select SND_SOC_INTEL_SST_FIRMWARE
 	select SND_SOC_INTEL_HASWELL
 	select SND_SOC_RT5640
 	help
@@ -91,8 +98,9 @@ config SND_SOC_INTEL_BXT_RT298_MACH
 config SND_SOC_INTEL_BYT_RT5640_MACH
 	tristate "ASoC Audio driver for Intel Baytrail with RT5640 codec"
 	depends on X86_INTEL_LPSS && I2C
-	depends on DW_DMAC_CORE=y && (SND_SST_IPC_ACPI = n)
+	depends on DW_DMAC_CORE && (SND_SST_IPC_ACPI = n)
 	select SND_SOC_INTEL_SST
+	select SND_SOC_INTEL_SST_FIRMWARE
 	select SND_SOC_INTEL_BAYTRAIL
 	select SND_SOC_RT5640
 	help
@@ -103,8 +111,9 @@ config SND_SOC_INTEL_BYT_RT5640_MACH
 config SND_SOC_INTEL_BYT_MAX98090_MACH
 	tristate "ASoC Audio driver for Intel Baytrail with MAX98090 codec"
 	depends on X86_INTEL_LPSS && I2C
-	depends on DW_DMAC_CORE=y && (SND_SST_IPC_ACPI = n)
+	depends on DW_DMAC_CORE && (SND_SST_IPC_ACPI = n)
 	select SND_SOC_INTEL_SST
+	select SND_SOC_INTEL_SST_FIRMWARE
 	select SND_SOC_INTEL_BAYTRAIL
 	select SND_SOC_MAX98090
 	help
@@ -115,8 +124,9 @@ config SND_SOC_INTEL_BROADWELL_MACH
 	tristate "ASoC Audio DSP support for Intel Broadwell Wildcatpoint"
 	depends on X86_INTEL_LPSS && I2C && DW_DMAC && \
 		   I2C_DESIGNWARE_PLATFORM
-	depends on DW_DMAC_CORE=y
+	depends on DW_DMAC_CORE
 	select SND_SOC_INTEL_SST
+	select SND_SOC_INTEL_SST_FIRMWARE
 	select SND_SOC_INTEL_HASWELL
 	select SND_SOC_RT286
 	help

sound/soc/intel/common/Makefile

@@ -2,9 +2,9 @@ snd-soc-sst-dsp-objs := sst-dsp.o
 snd-soc-sst-acpi-objs := sst-acpi.o
 snd-soc-sst-match-objs := sst-match-acpi.o
 snd-soc-sst-ipc-objs := sst-ipc.o
-
-snd-soc-sst-dsp-$(CONFIG_DW_DMAC_CORE) += sst-firmware.o
+snd-soc-sst-firmware-objs := sst-firmware.o
 
 obj-$(CONFIG_SND_SOC_INTEL_SST) += snd-soc-sst-dsp.o snd-soc-sst-ipc.o
 obj-$(CONFIG_SND_SOC_INTEL_SST_ACPI) += snd-soc-sst-acpi.o
 obj-$(CONFIG_SND_SOC_INTEL_SST_MATCH) += snd-soc-sst-match.o
+obj-$(CONFIG_SND_SOC_INTEL_SST_FIRMWARE) += snd-soc-sst-firmware.o

sound/soc/intel/common/sst-dsp-priv.h

@@ -383,10 +383,6 @@ struct sst_mem_block *sst_mem_block_register(struct sst_dsp *dsp, u32 offset,
 	u32 index, void *private);
 void sst_mem_block_unregister_all(struct sst_dsp *dsp);
 
-/* Create/Free DMA resources */
-int sst_dma_new(struct sst_dsp *sst);
-void sst_dma_free(struct sst_dma *dma);
-
 u32 sst_dsp_get_offset(struct sst_dsp *dsp, u32 offset,
 	enum sst_mem_type type);
 #endif

sound/soc/intel/common/sst-dsp.c

@@ -420,73 +420,6 @@ void sst_dsp_inbox_read(struct sst_dsp *sst, void *message, size_t bytes)
 }
 EXPORT_SYMBOL_GPL(sst_dsp_inbox_read);
 
-#ifdef CONFIG_DW_DMAC_CORE
-struct sst_dsp *sst_dsp_new(struct device *dev,
-	struct sst_dsp_device *sst_dev, struct sst_pdata *pdata)
-{
-	struct sst_dsp *sst;
-	int err;
-
-	dev_dbg(dev, "initialising audio DSP id 0x%x\n", pdata->id);
-
-	sst = devm_kzalloc(dev, sizeof(*sst), GFP_KERNEL);
-	if (sst == NULL)
-		return NULL;
-
-	spin_lock_init(&sst->spinlock);
-	mutex_init(&sst->mutex);
-	sst->dev = dev;
-	sst->dma_dev = pdata->dma_dev;
-	sst->thread_context = sst_dev->thread_context;
-	sst->sst_dev = sst_dev;
-	sst->id = pdata->id;
-	sst->irq = pdata->irq;
-	sst->ops = sst_dev->ops;
-	sst->pdata = pdata;
-	INIT_LIST_HEAD(&sst->used_block_list);
-	INIT_LIST_HEAD(&sst->free_block_list);
-	INIT_LIST_HEAD(&sst->module_list);
-	INIT_LIST_HEAD(&sst->fw_list);
-	INIT_LIST_HEAD(&sst->scratch_block_list);
-
-	/* Initialise SST Audio DSP */
-	if (sst->ops->init) {
-		err = sst->ops->init(sst, pdata);
-		if (err < 0)
-			return NULL;
-	}
-
-	/* Register the ISR */
-	err = request_threaded_irq(sst->irq, sst->ops->irq_handler,
-		sst_dev->thread, IRQF_SHARED, "AudioDSP", sst);
-	if (err)
-		goto irq_err;
-
-	err = sst_dma_new(sst);
-	if (err)
-		dev_warn(dev, "sst_dma_new failed %d\n", err);
-
-	return sst;
-
-irq_err:
-	if (sst->ops->free)
-		sst->ops->free(sst);
-
-	return NULL;
-}
-EXPORT_SYMBOL_GPL(sst_dsp_new);
-
-void sst_dsp_free(struct sst_dsp *sst)
-{
-	free_irq(sst->irq, sst);
-	if (sst->ops->free)
-		sst->ops->free(sst);
-
-	sst_dma_free(sst->dma);
-}
-EXPORT_SYMBOL_GPL(sst_dsp_free);
-#endif
-
 /* Module information */
 MODULE_AUTHOR("Liam Girdwood");
 MODULE_DESCRIPTION("Intel SST Core");

sound/soc/intel/common/sst-dsp.h

@@ -216,7 +216,7 @@ struct sst_pdata {
 	void *dsp;
 };
 
-#ifdef CONFIG_DW_DMAC_CORE
+#if IS_ENABLED(CONFIG_DW_DMAC_CORE)
 /* Initialization */
 struct sst_dsp *sst_dsp_new(struct device *dev,
 	struct sst_dsp_device *sst_dev, struct sst_pdata *pdata);

sound/soc/intel/common/sst-firmware.c

@@ -1211,3 +1211,71 @@ u32 sst_dsp_get_offset(struct sst_dsp *dsp, u32 offset,
 	}
 }
 EXPORT_SYMBOL_GPL(sst_dsp_get_offset);
+
+struct sst_dsp *sst_dsp_new(struct device *dev,
+	struct sst_dsp_device *sst_dev, struct sst_pdata *pdata)
+{
+	struct sst_dsp *sst;
+	int err;
+
+	dev_dbg(dev, "initialising audio DSP id 0x%x\n", pdata->id);
+
+	sst = devm_kzalloc(dev, sizeof(*sst), GFP_KERNEL);
+	if (sst == NULL)
+		return NULL;
+
+	spin_lock_init(&sst->spinlock);
+	mutex_init(&sst->mutex);
+	sst->dev = dev;
+	sst->dma_dev = pdata->dma_dev;
+	sst->thread_context = sst_dev->thread_context;
+	sst->sst_dev = sst_dev;
+	sst->id = pdata->id;
+	sst->irq = pdata->irq;
+	sst->ops = sst_dev->ops;
+	sst->pdata = pdata;
+	INIT_LIST_HEAD(&sst->used_block_list);
+	INIT_LIST_HEAD(&sst->free_block_list);
+	INIT_LIST_HEAD(&sst->module_list);
+	INIT_LIST_HEAD(&sst->fw_list);
+	INIT_LIST_HEAD(&sst->scratch_block_list);
+
+	/* Initialise SST Audio DSP */
+	if (sst->ops->init) {
+		err = sst->ops->init(sst, pdata);
+		if (err < 0)
+			return NULL;
+	}
+
+	/* Register the ISR */
+	err = request_threaded_irq(sst->irq, sst->ops->irq_handler,
+		sst_dev->thread, IRQF_SHARED, "AudioDSP", sst);
+	if (err)
+		goto irq_err;
+
+	err = sst_dma_new(sst);
+	if (err)
+		dev_warn(dev, "sst_dma_new failed %d\n", err);
+
+	return sst;
+
+irq_err:
+	if (sst->ops->free)
+		sst->ops->free(sst);
+
+	return NULL;
+}
+EXPORT_SYMBOL_GPL(sst_dsp_new);
+
+void sst_dsp_free(struct sst_dsp *sst)
+{
+	free_irq(sst->irq, sst);
+	if (sst->ops->free)
+		sst->ops->free(sst);
+
+	sst_dma_free(sst->dma);
+}
+EXPORT_SYMBOL_GPL(sst_dsp_free);
+
+MODULE_DESCRIPTION("Intel SST Firmware Loader");
+MODULE_LICENSE("GPL v2");