acpi/device: Add ability to generate proper _STA for PowerResource

acpi_device_add_power_res currently generates a `_STA` method hardcoded
to ON. This change enables the ability to generate a `_STA` method that
queries the status of the GPIOs to determine if the power resource is ON
or OFF.

BUG=b:184617186
TEST=Dump SSDT table for guybrush

Signed-off-by: Raul E Rangel <rrangel@chromium.org>
Change-Id: I91410556db002c620fd9aaa99981457808da93a5
Reviewed-on: https://review.coreboot.org/c/coreboot/+/55027
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Lance Zhao
Reviewed-by: Tim Wawrzynczak <twawrzynczak@chromium.org>

1 files changed, 50 insertions, 2 deletions

diff --git a/src/acpi/device.c b/src/acpi/device.c
index 5d4d9be4ce..42fa63985b 100644
--- a/src/acpi/device.c
+++ b/src/acpi/device.c
@@ -598,6 +598,50 @@ void acpi_device_write_uart(const struct acpi_uart *uart)
 	acpi_device_fill_len(desc_length);
 }
 
+#define ACPI_POWER_RESOURCE_STATUS_ON_OP	ONE_OP
+#define ACPI_POWER_RESOURCE_STATUS_OFF_OP	ZERO_OP
+
+/**
+ * Writes an ACPI fragment that will check the GPIO and return 0 if the GPIO
+ * state does not match the active parameter.
+ */
+static void acpigen_write_gpio_STA(const struct acpi_gpio *gpio, bool active)
+{
+	if (!gpio || !gpio->pin_count)
+		return;
+
+	/* Read current GPIO status into Local0. */
+	acpigen_get_tx_gpio(gpio);
+
+	/*
+	 * If (!Local0)
+	 * {
+	 *     Return (Zero)
+	 * }
+	 */
+	acpigen_write_if();
+	if (active)
+		acpigen_emit_byte(LNOT_OP);
+	acpigen_emit_byte(LOCAL0_OP);
+	acpigen_write_return_op(ACPI_POWER_RESOURCE_STATUS_OFF_OP);
+	acpigen_write_if_end();
+}
+
+static void acpigen_write_power_res_STA(const struct acpi_power_res_params *params)
+{
+	acpigen_write_method_serialized("_STA", 0);
+
+	/* Verify all the GPIOs are in the ON state, otherwise return 0 */
+	acpigen_write_gpio_STA(params->enable_gpio, true);
+	acpigen_write_gpio_STA(params->reset_gpio, false);
+	acpigen_write_gpio_STA(params->stop_gpio, false);
+
+	/* All GPIOs are in the ON state */
+	acpigen_write_return_op(ACPI_POWER_RESOURCE_STATUS_ON_OP);
+
+	acpigen_pop_len(); /* Method */
+}
+
 /* PowerResource() with Enable and/or Reset control */
 void acpi_device_add_power_res(const struct acpi_power_res_params *params)
 {
@@ -613,8 +657,12 @@ void acpi_device_add_power_res(const struct acpi_power_res_params *params)
 	acpigen_write_power_res("PRIC", 0, 0, power_res_dev_states,
 				ARRAY_SIZE(power_res_dev_states));
 
-	/* Method (_STA, 0, NotSerialized) { Return (0x1) } */
-	acpigen_write_STA(0x1);
+	if (params->use_gpio_for_status) {
+		acpigen_write_power_res_STA(params);
+	} else {
+		/* Method (_STA, 0, NotSerialized) { Return (0x1) } */
+		acpigen_write_STA(ACPI_POWER_RESOURCE_STATUS_ON_OP);
+	}
 
 	/* Method (_ON, 0, Serialized) */
 	acpigen_write_method_serialized("_ON", 0);