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

The recent commit [a92ea59b74e2: 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: a92ea59b74e2 ('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>

1 files changed, 2 insertions, 2 deletions

diff --git a/sound/soc/intel/common/Makefile b/sound/soc/intel/common/Makefile
index fbbb25c2ceed..1a35149bcad7 100644
--- a/sound/soc/intel/common/Makefile
+++ b/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