soc/amd/picasso: Add support for generating I2S machine device

This change adds support in ACP device driver to generate I2S machine
device (AMDI5682) in SSDT. It expects mainboard to provide chip config
`dmic_select_gpio` that can be passed as `dmic-gpios` in _DSD for the
device.

BUG=b:157603026
TEST=Verified that I2S machine device is correctly generated for
trembyle.

Signed-off-by: Furquan Shaikh <furquan@google.com>
Change-Id: I22ab53d7d68c6e042e467e598d688e360d28586f
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/third_party/coreboot/+/2252557
Commit-Queue: Furquan Shaikh <furquan@chromium.org>
Tested-by: Furquan Shaikh <furquan@chromium.org>
Reviewed-by: Aaron Durbin <adurbin@google.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/42970
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Aaron Durbin <adurbin@chromium.org>

2 files changed, 60 insertions, 1 deletions

diff --git a/src/soc/amd/picasso/acp.c b/src/soc/amd/picasso/acp.c
index 1e871e99d8..3272acf8f6 100644
--- a/src/soc/amd/picasso/acp.c
+++ b/src/soc/amd/picasso/acp.c
@@ -1,5 +1,7 @@
 /* SPDX-License-Identifier: GPL-2.0-only */
 
+#include <acpi/acpi_device.h>
+#include <acpi/acpigen.h>
 #include <console/console.h>
 #include <device/device.h>
 #include <device/pci.h>
@@ -40,6 +42,60 @@ static const char *acp_acpi_name(const struct device *dev)
 	return "ACPD";
 }
 
+#define AMD_I2S_ACPI_NAME	"I2SM"
+#define AMD_I2S_ACPI_HID	"AMDI5682"
+#define AMD_I2S_ACPI_DESC	"I2S machine driver"
+
+static void acp_fill_i2s_machine_dev(const struct device *dev)
+{
+	const char *scope = acpi_device_path(dev);
+	const struct soc_amd_picasso_config *cfg = config_of_soc();
+	const struct acpi_gpio *dmic_select_gpio = &cfg->dmic_select_gpio;
+	struct acpi_dp *dsd;
+
+	if (dmic_select_gpio->pin_count == 0)
+		return;
+
+	acpigen_write_scope(scope); /* Scope */
+	acpigen_write_device(AMD_I2S_ACPI_NAME); /* Device */
+	acpigen_write_name_string("_HID", AMD_I2S_ACPI_HID);
+	acpigen_write_name_integer("_UID", 1);
+	acpigen_write_name_string("_DDN", AMD_I2S_ACPI_DESC);
+
+	acpigen_write_STA(ACPI_STATUS_DEVICE_ALL_ON);
+
+	/* Resources */
+	acpigen_write_name("_CRS");
+	acpigen_write_resourcetemplate_header();
+	acpi_device_write_gpio(dmic_select_gpio);
+	acpigen_write_resourcetemplate_footer();
+
+	dsd = acpi_dp_new_table("_DSD");
+	/*
+	 * This GPIO is used to select DMIC0 or DMIC1 by the kernel driver. It does not
+	 * really have a polarity since low and high control the selection of DMIC and
+	 * hence does not have an active polarity.
+	 * Kernel driver does not use the polarity field and instead treats the GPIO
+	 * selection as follows:
+	 * Set low (0) = Select DMIC0
+	 * Set high (1) = Select DMIC1
+	 */
+	acpi_dp_add_gpio(dsd, "dmic-gpios", acpi_device_path_join(dev, AMD_I2S_ACPI_NAME),
+			 0,  /* Index = 0 (There is a single GPIO entry in _CRS). */
+			 0,  /* Pin = 0 (There is a single pin in the GPIO resource). */
+			 0); /* Active low = 0 (Kernel driver does not use active polarity). */
+	acpi_dp_write(dsd);
+
+	acpigen_pop_len(); /* Device */
+	acpigen_pop_len(); /* Scope */
+}
+
+static void acp_fill_ssdt(const struct device *dev)
+{
+	acpi_device_write_pci_dev(dev);
+	acp_fill_i2s_machine_dev(dev);
+}
+
 static struct device_operations acp_ops = {
 	.read_resources = pci_dev_read_resources,
 	.set_resources = pci_dev_set_resources,
@@ -47,7 +103,7 @@ static struct device_operations acp_ops = {
 	.init = init,
 	.ops_pci = &pci_dev_ops_pci,
 	.acpi_name = acp_acpi_name,
-	.acpi_fill_ssdt = acpi_device_write_pci_dev,
+	.acpi_fill_ssdt = acp_fill_ssdt,
 };
 
 static const struct pci_driver acp_driver __pci_driver = {
diff --git a/src/soc/amd/picasso/chip.h b/src/soc/amd/picasso/chip.h
index f5fbe0fc2e..f11f800787 100644
--- a/src/soc/amd/picasso/chip.h
+++ b/src/soc/amd/picasso/chip.h
@@ -46,6 +46,9 @@ struct soc_amd_picasso_config {
 		uint8_t flags;
 	} irq_override[16];
 
+	/* DMIC select GPIO for I2S machine driver AMDI5682 */
+	struct acpi_gpio dmic_select_gpio;
+
 	/* Options for these are in src/arch/x86/include/acpi/acpi.h */
 	uint8_t  fadt_pm_profile;
 	uint16_t fadt_boot_arch;