The emulation system for eSPI

boards/posix/native_posix/native_posix.dts

@@ -112,6 +112,15 @@
 		label = "SPI_0";
 	};
 
+	espi0: espi@300 {
+		status = "okay";
+		compatible = "zephyr,espi-emul-controller";
+		reg = <0x300 4>;
+		#address-cells = <1>;
+		#size-cells = <0>;
+		label = "ESPI_0";
+	};
+
 	uart0: uart {
 		status = "okay";
 		compatible = "zephyr,native-posix-uart";

doc/guides/emulator/index.rst

@@ -85,6 +85,9 @@ Zephyr includes the following emulators:
 
 * SPI emulator driver, which does the same for SPI
 
+* eSPI emulator driver, which does the same for eSPI. The emulator is being
+  developed to support more functionalities.
+
 A GPIO emulator is planned but is not yet complete.
 
 Samples

drivers/espi/CMakeLists.txt

@@ -6,3 +6,4 @@ zephyr_library_sources_ifdef(CONFIG_ESPI_XEC		espi_mchp_xec.c)
 zephyr_library_sources_ifdef(CONFIG_ESPI_NPCX           espi_npcx.c)
 zephyr_library_sources_ifdef(CONFIG_ESPI_NPCX           host_subs_npcx.c)
 zephyr_library_sources_ifdef(CONFIG_USERSPACE           espi_handlers.c)
+zephyr_library_sources_ifdef(CONFIG_ESPI_EMUL           espi_emul.c)

drivers/espi/Kconfig

@@ -14,6 +14,8 @@ source "drivers/espi/Kconfig.xec"
 
 source "drivers/espi/Kconfig.npcx"
 
+source "drivers/espi/Kconfig.espi_emul"
+
 module = ESPI
 module-str = espi
 source "subsys/logging/Kconfig.template.log_config"

drivers/espi/Kconfig.espi_emul

@@ -0,0 +1,16 @@
+# Copyright 2020 Google LLC
+# SPDX-License-Identifier: Apache-2.0
+
+config ESPI_EMUL
+	bool "eSPI emulator"
+	help
+	  Enable the eSPI emulator driver. This is a fake driver,
+	  it does not talk to real hardware. Instead it talks to emulation
+	  drivers that pretend to be devices on the emulated eSPI bus. It is
+	  used for testing drivers for eSPI devices.
+
+	  eSPI is an interface using SPI wires, whose main goal is to reduce the
+	  number of required pins. It includes the functionality of LPC, SMB, SPI
+	  itself (flash access) and GPIO (virtual wires). Please refer to the
+	  specification for more details (it is good for the introduction as well)
+	  https://www.intel.com/content/dam/support/us/en/documents/software/chipset-software/327432-004_espi_base_specification_rev1.0_cb.pdf

drivers/espi/espi_emul.c

@@ -0,0 +1,207 @@
+/*
+ * Copyright 2020 Google LLC
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * This driver creates fake eSPI buses which can contain emulated devices
+ * (mainly host), implemented by a separate emulation driver.
+ * The API between this driver/controller and device emulators attached
+ * to its bus is defined by struct emul_espi_device_api.
+ */
+
+#define DT_DRV_COMPAT zephyr_espi_emul_controller
+
+#define LOG_LEVEL CONFIG_ESPI_LOG_LEVEL
+#include <logging/log.h>
+LOG_MODULE_REGISTER(espi_emul_ctlr);
+
+#include <device.h>
+#include <emul.h>
+#include <drivers/espi.h>
+#include <drivers/espi_emul.h>
+#include "espi_utils.h"
+
+/** Working data for the controller */
+struct espi_emul_data {
+	/* List of struct espi_emul associated with the device */
+	sys_slist_t emuls;
+	/* eSPI host configuration */
+	struct espi_cfg cfg;
+	/** List of eSPI callbacks */
+	sys_slist_t callbacks;
+};
+
+static struct espi_emul *espi_emul_find(const struct device *dev,
+					unsigned int chipsel)
+{
+	struct espi_emul_data *data = dev->data;
+	sys_snode_t *node;
+
+	SYS_SLIST_FOR_EACH_NODE(&data->emuls, node) {
+		struct espi_emul *emul;
+
+		emul = CONTAINER_OF(node, struct espi_emul, node);
+		if (emul->chipsel == chipsel) {
+			return emul;
+		}
+	}
+
+	return NULL;
+}
+
+static int espi_emul_config(const struct device *dev, struct espi_cfg *cfg)
+{
+	struct espi_emul_data *data = dev->data;
+
+	__ASSERT_NO_MSG(cfg);
+
+	data->cfg = *cfg;
+
+	return 0;
+}
+
+
+static int emul_espi_trigger_event(const struct device *dev,
+				   struct espi_event *evt)
+{
+	struct espi_emul_data *data = dev->data;
+
+	if (((evt->evt_type & ESPI_BUS_EVENT_VWIRE_RECEIVED) &&
+	     !(data->cfg.channel_caps & ESPI_CHANNEL_VWIRE)) ||
+	    ((evt->evt_type & ESPI_BUS_EVENT_OOB_RECEIVED) &&
+	     !(data->cfg.channel_caps & ESPI_CHANNEL_OOB)) ||
+	    ((evt->evt_type & ESPI_BUS_PERIPHERAL_NOTIFICATION)
+	     && !(data->cfg.channel_caps & ESPI_CHANNEL_PERIPHERAL))) {
+		return -EIO;
+	}
+
+	espi_send_callbacks(&data->callbacks, dev, *evt);
+
+	return 0;
+}
+
+static bool espi_emul_get_channel_status(const struct device *dev, enum espi_channel ch)
+{
+	struct espi_emul_data *data = dev->data;
+
+	return (data->cfg.channel_caps & ch);
+}
+
+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;
+	struct espi_emul *emul;
+	struct espi_emul_data *data = dev->data;
+
+	if (!(data->cfg.channel_caps & ESPI_CHANNEL_VWIRE)) {
+		return -EIO;
+	}
+
+	emul = espi_emul_find(dev, EMUL_ESPI_HOST_CHIPSEL);
+	if (!emul) {
+		LOG_DBG("espi_emul not found");
+		return -EIO;
+	}
+
+	__ASSERT_NO_MSG(emul->api);
+	__ASSERT_NO_MSG(emul->api->set_vw);
+	api = emul->api;
+
+	return api->set_vw(emul, vw, level);
+}
+
+static int espi_emul_receive_vwire(const struct device *dev, enum espi_vwire_signal vw, uint8_t *level)
+{
+	const struct emul_espi_device_api *api;
+	struct espi_emul *emul;
+	struct espi_emul_data *data = dev->data;
+
+	if (!(data->cfg.channel_caps & ESPI_CHANNEL_VWIRE)) {
+		return -EIO;
+	}
+
+	emul = espi_emul_find(dev, EMUL_ESPI_HOST_CHIPSEL);
+	if (!emul) {
+		LOG_INF("espi_emul not found");
+		return -EIO;
+	}
+
+	__ASSERT_NO_MSG(emul->api);
+	__ASSERT_NO_MSG(emul->api->get_vw);
+	api = emul->api;
+
+	return api->get_vw(emul, vw, level);
+}
+
+static int espi_emul_manage_callback(const struct device *dev, struct espi_callback *callback, bool set)
+{
+	struct espi_emul_data *data = dev->data;
+
+	return espi_manage_callback(&data->callbacks, callback, set);
+}
+
+/**
+ * Set up a new emulator and add it to the list
+ *
+ * @param dev eSPI emulation controller device
+ */
+static int espi_emul_init(const struct device *dev)
+{
+	struct espi_emul_data *data = dev->data;
+	const struct emul_list_for_bus *list = dev->config;
+
+	sys_slist_init(&data->emuls);
+
+	return emul_init_for_bus_from_list(dev, list);
+}
+
+int espi_emul_register(const struct device *dev, const char *name,
+		       struct espi_emul *emul)
+{
+	struct espi_emul_data *data = dev->data;
+
+	sys_slist_append(&data->emuls, &emul->node);
+
+	LOG_INF("Register emulator '%s' at cs %u\n", name, emul->chipsel);
+
+	return 0;
+}
+
+/* Device instantiation */
+static struct emul_espi_driver_api emul_espi_driver_api = {
+	.espi_api = {
+		.config = espi_emul_config,
+		.get_channel_status = espi_emul_get_channel_status,
+		.send_vwire = espi_emul_send_vwire,
+		.receive_vwire = espi_emul_receive_vwire,
+		.manage_callback = espi_emul_manage_callback
+	},
+	.trigger_event = emul_espi_trigger_event,
+	.find_emul = espi_emul_find,
+};
+
+
+#define EMUL_LINK_AND_COMMA(node_id) {	    \
+		.label = DT_LABEL(node_id), \
+},
+
+#define ESPI_EMUL_INIT(n)					      \
+	static const struct emul_link_for_bus emuls_##n[] = {	      \
+		DT_FOREACH_CHILD(DT_DRV_INST(n), EMUL_LINK_AND_COMMA) \
+	};							      \
+	static struct emul_list_for_bus espi_emul_cfg_##n = {	      \
+		.children = emuls_##n,				      \
+		.num_children = ARRAY_SIZE(emuls_##n),		      \
+	};							      \
+	static struct espi_emul_data espi_emul_data_##n;	      \
+	DEVICE_DT_INST_DEFINE(n,				      \
+			      &espi_emul_init,			      \
+			      device_pm_control_nop,		      \
+			      &espi_emul_data_##n,		      \
+			      &espi_emul_cfg_##n,		      \
+			      POST_KERNEL,			      \
+			      CONFIG_ESPI_INIT_PRIORITY,	      \
+			      &emul_espi_driver_api);
+
+
+DT_INST_FOREACH_STATUS_OKAY(ESPI_EMUL_INIT)

dts/bindings/espi/zephyr,espi-emul.yaml

@@ -0,0 +1,12 @@
+# Copyright 2020 Google LLC
+# SPDX-License-Identifier: Apache-2.0
+
+description: Zephyr eSPI Emulation controller
+
+compatible: "zephyr,espi-emul-controller"
+
+include: espi-controller.yaml
+
+properties:
+    reg:
+      required: true