emul: espi: Add ACPI Shared Memory functions

Add the bare minimum to set and access the ACPI shared memory via the
eSPI emulator.

Signed-off-by: Yuval Peress <peress@chromium.org>

drivers/espi/espi_emul.c

@@ -87,6 +87,49 @@ static bool espi_emul_get_channel_status(const struct device *dev, enum espi_cha
 	return (data->cfg.channel_caps & ch);
 }
 
+static int espi_emul_read_lpc_request(const struct device *dev,
+				      enum lpc_peripheral_opcode op,
+				      uint32_t *data)
+{
+	const struct emul_espi_device_api *api;
+	struct espi_emul *emul;
+	struct espi_emul_data *emul_data = dev->data;
+
+	if (!(emul_data->cfg.channel_caps & ESPI_CHANNEL_VWIRE)) {
+		LOG_ERR("bad channel vwire");
+		return -EINVAL;
+	}
+
+	emul = espi_emul_find(dev, EMUL_ESPI_HOST_CHIPSEL);
+	if (!emul) {
+		LOG_ERR("espi_emul not found");
+		return -ENOTSUP;
+	}
+
+	__ASSERT_NO_MSG(emul->api);
+	api = emul->api;
+
+	switch (op) {
+#ifdef CONFIG_ESPI_PERIPHERAL_ACPI_SHM_REGION
+	case EACPI_GET_SHARED_MEMORY:
+		__ASSERT_NO_MSG(api->get_acpi_shm);
+		*data = (uint32_t)api->get_acpi_shm(emul);
+		break;
+#endif
+	default:
+		return -EINVAL;
+	}
+	return 0;
+}
+
+static int espi_emul_write_lpc_request(const struct device *dev, enum lpc_peripheral_opcode op,
+				       uint32_t *data)
+{
+	ARG_UNUSED(dev);
+
+	return -EINVAL;
+}
+
 static int espi_emul_send_vwire(const struct device *dev, enum espi_vwire_signal vw, uint8_t level)
 {
 	const struct emul_espi_device_api *api;
@@ -172,6 +215,8 @@ static struct emul_espi_driver_api emul_espi_driver_api = {
 	.espi_api = {
 		.config = espi_emul_config,
 		.get_channel_status = espi_emul_get_channel_status,
+		.read_lpc_request = espi_emul_read_lpc_request,
+		.write_lpc_request = espi_emul_write_lpc_request,
 		.send_vwire = espi_emul_send_vwire,
 		.receive_vwire = espi_emul_receive_vwire,
 		.manage_callback = espi_emul_manage_callback

include/drivers/espi_emul.h

@@ -61,6 +61,17 @@ typedef int (*emul_espi_api_get_vw)(struct espi_emul *emul,
 				    enum espi_vwire_signal vw,
 				    uint8_t *level);
 
+#ifdef CONFIG_ESPI_PERIPHERAL_ACPI_SHM_REGION
+/**
+ * Get the ACPI shared memory address owned by the emulator.
+ *
+ * @param emul Emulator instance.
+ *
+ * @retval The address of the memory.
+ */
+typedef uintptr_t (*emul_espi_api_get_acpi_shm)(struct espi_emul *emul);
+#endif
+
 /**
  * Find an emulator present on a eSPI bus
  *
@@ -88,11 +99,13 @@ typedef struct espi_emul *(*emul_find_emul)(const struct device *dev,
 typedef int (*emul_trigger_event)(const struct device *dev,
 				  struct espi_event *evt);
 
-
 /** Definition of the eSPI device emulator API */
 struct emul_espi_device_api {
 	emul_espi_api_set_vw set_vw;
 	emul_espi_api_get_vw get_vw;
+#ifdef CONFIG_ESPI_PERIPHERAL_ACPI_SHM_REGION
+	emul_espi_api_get_acpi_shm get_acpi_shm;
+#endif
 };
 
 /** Node in a linked list of emulators for eSPI devices */
@@ -152,6 +165,18 @@ int emul_espi_host_send_vw(const struct device *espi_dev,
  */
 int emul_espi_host_port80_write(const struct device *espi_dev, uint32_t data);
 
+#ifdef CONFIG_ESPI_PERIPHERAL_ACPI_SHM_REGION
+/**
+ * Get the host device's ACPI shared memory start address. The size of the region is
+ * CONFIG_EMUL_ESPI_HOST_ACPI_SHM_REGION_SIZE.
+ *
+ * @param espi_dev eSPI emulation controller device.
+ * @return Address of the start of the ACPI shared memory.
+ */
+uintptr_t emul_espi_host_get_acpi_shm(const struct device *espi_dev);
+#endif
+
+
 #ifdef __cplusplus
 }
 #endif

subsys/emul/espi/Kconfig

@@ -9,3 +9,15 @@ config EMUL_ESPI_HOST
 	  This is an emulator of the generic eSPI host. The emulator supports
 	  basic host operations - virtual wires and writing to port 80. It can be
 	  extended.
+
+if EMUL_ESPI_HOST
+
+config EMUL_ESPI_HOST_ACPI_SHM_REGION_SIZE
+	int "Host I/O peripheral port size for shared memory in emulator"
+	depends on ESPI_PERIPHERAL_ACPI_SHM_REGION
+	default 256
+	help
+	  This is the port size used to mimic the Host and EC communication
+	  over the shared memory region which returns the ACPI response data.
+
+endif # EMUL_ESPI_HOST

subsys/emul/espi/emul_espi_host.c

@@ -73,6 +73,10 @@ struct espi_host_emul_data {
 	/** Virtual Wires states, for one slave only.
 	 *  With multi-slaves config, the states should be saved per slave */
 	struct vw_data vw_state[NUMBER_OF_VWIRES];
+#ifdef CONFIG_ESPI_PERIPHERAL_ACPI_SHM_REGION
+	/** ACPI Shared memory. */
+	uint8_t shm_acpi_mmap[CONFIG_EMUL_ESPI_HOST_ACPI_SHM_REGION_SIZE];
+#endif
 };
 
 /** Static configuration for the emulator */
@@ -217,10 +221,31 @@ int emul_espi_host_port80_write(const struct device *espi_dev, uint32_t data)
 	return 0;
 }
 
+#ifdef CONFIG_ESPI_PERIPHERAL_ACPI_SHM_REGION
+static uintptr_t emul_espi_dev_get_acpi_shm(struct espi_emul *emul)
+{
+	struct espi_host_emul_data *data =
+		CONTAINER_OF(emul, struct espi_host_emul_data, emul);
+
+	return (uintptr_t)data->shm_acpi_mmap;
+}
+
+uintptr_t emul_espi_host_get_acpi_shm(const struct device *espi_dev)
+{
+	uint32_t shm;
+	int rc = espi_read_lpc_request(espi_dev, EACPI_GET_SHARED_MEMORY, &shm);
+
+	__ASSERT_NO_MSG(rc == 0);
+
+	return (uintptr_t) shm;
+}
+#endif
+
 /* Device instantiation */
 static struct emul_espi_device_api ap_emul_api = {
 	.set_vw = emul_host_set_vw,
 	.get_vw = emul_host_get_vw,
+	.get_acpi_shm = emul_espi_dev_get_acpi_shm,
 };
 
 /**

tests/drivers/espi/CMakeLists.txt

@@ -0,0 +1,10 @@
+# Copyright 2021 Google LLC
+# SPDX-License-Identifier: Apache-2.0
+
+cmake_minimum_required(VERSION 3.13.1)
+
+find_package(Zephyr REQUIRED HINTS $ENV{ZEPHYR_BASE})
+project(espi)
+
+FILE(GLOB app_sources src/*.c)
+target_sources(app PRIVATE ${app_sources})

tests/drivers/espi/boards/native_posix.overlay

@@ -0,0 +1,14 @@
+/*
+ * Copyright 2021 Google LLC
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+&espi0 {
+	espi_host: espi-host@0 {
+		status = "okay";
+		compatible = "zephyr,espi-emul-espi-host";
+		reg = <0x0>;
+		label = "ESPI_HOST";
+	};
+};

tests/drivers/espi/prj.conf

@@ -0,0 +1,11 @@
+# Copyright 2021 Google LLC
+# SPDX-License-Identifier: Apache-2.0
+
+CONFIG_ZTEST=y
+CONFIG_ESPI=y
+CONFIG_EMUL=y
+CONFIG_ESPI_EMUL=y
+CONFIG_EMUL_ESPI_HOST=y
+
+CONFIG_ESPI_PERIPHERAL_CHANNEL=y
+CONFIG_ESPI_PERIPHERAL_ACPI_SHM_REGION=y

tests/drivers/espi/src/test_acpi.c

@@ -0,0 +1,38 @@
+/*
+ * Copyright 2021 Google LLC
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+#include <device.h>
+#include <drivers/espi.h>
+#include <drivers/espi_emul.h>
+#include <ztest.h>
+
+static void test_acpi_shared_memory(void)
+{
+	const struct device *espi_dev = device_get_binding(DT_LABEL(DT_NODELABEL(espi0)));
+	struct espi_cfg cfg = {
+		.channel_caps = ESPI_CHANNEL_VWIRE | ESPI_CHANNEL_PERIPHERAL,
+	};
+	uintptr_t host_shm, peripheral_shm;
+
+	zassert_not_null(espi_dev, NULL);
+
+	zassert_ok(espi_config(espi_dev, &cfg), NULL);
+
+	host_shm = emul_espi_host_get_acpi_shm(espi_dev);
+	zassert_not_equal(host_shm, 0, NULL);
+
+	zassert_ok(espi_read_lpc_request(espi_dev, EACPI_GET_SHARED_MEMORY,
+					 (uint32_t *)&peripheral_shm),
+		   NULL);
+
+	zassert_equal(host_shm, peripheral_shm, NULL);
+}
+
+ztest_test_suite(acpi, ztest_unit_test(test_acpi_shared_memory));
+
+void test_main(void)
+{
+	ztest_run_test_suite(acpi);
+}

tests/drivers/espi/testcase.yaml

@@ -0,0 +1,11 @@
+# Copyright 2021 Google LLC
+# SPDX-License-Identifier: Apache-2.0
+
+tests:
+  drivers.espi.acpi:
+    tags: drivers espi
+    filter: dt_compat_enabled("zephyr,espi-emul-controller")
+    harness: ztest
+    platform_allow: native_posix
+    integration_platforms:
+      - native_posix