Change in coreboot[master]: acpi/device: Add ability to generate proper _STA for PowerResource

[Raul Rangel (Code Review)]

Attention is currently required from: Lance Zhao, Tim Wawrzynczak.
Raul Rangel has uploaded this change for review. ( https://review.coreboot.org/c/coreboot/+/55027 )

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

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.

The acpigen_write_power_res_STA method was copied from
soc/intel/common/block/pcie/rtd3.c:pcie_rtd3_acpi_method_status. I also
added support for checking the stop_gpio.

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

Signed-off-by: Raul E Rangel 
Change-Id: I91410556db002c620fd9aaa99981457808da93a5
---
M src/acpi/device.c
M src/include/acpi/acpi_device.h
2 files changed, 40 insertions(+), 2 deletions(-)

git pull ssh://review.coreboot.org:29418/coreboot refs/changes/27/55027/1

diff --git a/src/acpi/device.c b/src/acpi/device.c
index 5d4d9be..dfbab3e 100644
--- a/src/acpi/device.c
+++ b/src/acpi/device.c
@@ -598,6 +598,35 @@
    acpi_device_fill_len(desc_length);
 }

+static void acpigen_write_power_res_STA(const struct acpi_power_res_params *params)
+{
+	const struct acpi_gpio *gpio;
+
+	acpigen_write_method("_STA", 0);
+
+	/* Use enable GPIO for status if provided, otherwise reset GPIO, and finally stop */
+	if (params->enable_gpio->pin_count)
+		gpio = params->enable_gpio;
+	else if (params->reset_gpio->pin_count)
+		gpio = params->reset_gpio;
+	else
+		gpio = params->stop_gpio;
+
+	/* Read current GPIO value into Local0. */
+	acpigen_get_tx_gpio(gpio);
+
+	/* Ensure check works for both active low and active high GPIOs. */
+	acpigen_write_store_int_to_op(gpio->active_low, LOCAL1_OP);
+
+	acpigen_write_if_lequal_op_op(LOCAL0_OP, LOCAL1_OP);
+	acpigen_write_return_op(ZERO_OP);
+	acpigen_write_else();
+	acpigen_write_return_op(ONE_OP);
+	acpigen_pop_len(); /* Else */
+
+	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 +642,12 @@
    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->enable_status) {
+		acpigen_write_power_res_STA(params);
+	} else {
+		/* Method (_STA, 0, NotSerialized) { Return (0x1) } */
+		acpigen_write_STA(0x1);
+	}

/* Method (_ON, 0, Serialized) */
    acpigen_write_method_serialized("_ON", 0);
diff --git a/src/include/acpi/acpi_device.h b/src/include/acpi/acpi_device.h
index 301f9b0..da936aa 100644
--- a/src/include/acpi/acpi_device.h
+++ b/src/include/acpi/acpi_device.h
@@ -456,6 +456,11 @@
     * (_OFF method delay)
     */
    unsigned int stop_off_delay_ms;
+
+	/* Write a _STA method that checks the state of the GPIOs. Otherwise
+	 * the _STA method will always return _ON.
+	 */
+	bool enable_status;
 };

/*