soc/intel/apollolake: Add Audio DSP device

Add the Audio DSP device for apollolake as a PCI driver with a static
scan_bus handler so generic devices can be declared under it.

This is for devices like the Maxim 98357A which is connected on the
I2S bus for data but has no control channel bus and instead just has
a GPIO for channel selection and power down control and needs to
describe that GPIO connection to the OS via ACPI.

Change-Id: Icb97ccf7d6a9034877614d49166bc9e4fe659b12
Signed-off-by: Harsha Priya <harshapriya.n@intel.com>
Reviewed-on: https://review.coreboot.org/15528
Tested-by: build bot (Jenkins)
Reviewed-by: Aaron Durbin <adurbin@chromium.org>

src/soc/intel/apollolake/Makefile.inc

@@ -44,6 +44,7 @@ smm-y += uart_early.c
 ramstage-$(CONFIG_HAVE_ACPI_TABLES) += acpi.c
 ramstage-y += cpu.c
 ramstage-y += chip.c
+ramstage-y += dsp.c
 ramstage-y += gpio.c
 ramstage-y += graphics.c
 ramstage-y += i2c.c

src/soc/intel/apollolake/dsp.c

@@ -0,0 +1,32 @@
+/*
+ * This file is part of the coreboot project.
+ *
+ * Copyright 2016 Google Inc.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; version 2 of the License.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ */
+
+#include <device/device.h>
+#include <device/pci.h>
+#include <device/pci_ids.h>
+#include <soc/pci_ids.h>
+
+static struct device_operations dsp_dev_ops = {
+	.read_resources         = &pci_dev_read_resources,
+	.set_resources          = &pci_dev_set_resources,
+	.enable_resources       = &pci_dev_enable_resources,
+	.scan_bus               = &scan_static_bus,
+};
+
+static const struct pci_driver apollolake_dsp __pci_driver = {
+	.ops    = &dsp_dev_ops,
+	.vendor = PCI_VENDOR_ID_INTEL,
+	.device = PCI_DEVICE_ID_APOLLOLAKE_AUDIO
+};