zephyr: npcx: support SHI driver

Add the support for SHI (Serial Host Interface) driver. This is used to
transfer host commands between EC and ARM-based AP.

BUG=b:182600858
BRANCH=none
TEST=Test host command "version" and "Hello" on npcx7_evb and the host
emulator.

Signed-off-by: Jun Lin <CHLin56@nuvoton.com>
Change-Id: I5f290fe910600162764f5728f094dd0f42d508ef
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/ec/+/2786887
Reviewed-by: Jack Rosenthal <jrosenth@chromium.org>
Commit-Queue: Jack Rosenthal <jrosenth@chromium.org>
Tested-by: Jack Rosenthal <jrosenth@chromium.org>

1 files changed, 89 insertions, 0 deletions

diff --git a/zephyr/include/drivers/cros_shi.h b/zephyr/include/drivers/cros_shi.h
new file mode 100644
index 0000000000..aab3507dd3
--- /dev/null
+++ b/zephyr/include/drivers/cros_shi.h
@@ -0,0 +1,89 @@
+/* Copyright 2021 The Chromium OS Authors. All rights reserved.
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+/**
+ * @file
+ * @brief Chrome OS-specific API for Serial Host Interface (SHI)
+ */
+
+#ifndef ZEPHYR_INCLUDE_DRIVERS_CROS_SHI_H_
+#define ZEPHYR_INCLUDE_DRIVERS_CROS_SHI_H_
+
+/**
+ * @brief CROS Serial Host Interface Driver APIs
+ * @defgroup cros_shi_interface CROS Serial Host Interface Driver APIs
+ * @ingroup io_interfaces
+ * @{
+ */
+
+#include <kernel.h>
+#include <device.h>
+
+/**
+ * @cond INTERNAL_HIDDEN
+ *
+ * cros Serial Host Interface driver API definition and system call entry points
+ *
+ * (Internal use only.)
+ */
+typedef int (*cros_shi_api_enable)(const struct device *dev);
+
+typedef int (*cros_shi_api_disable)(const struct device *dev);
+
+/** @brief Driver API structure. */
+__subsystem struct cros_shi_driver_api {
+	cros_shi_api_enable enable;
+	cros_shi_api_disable disable;
+};
+
+/**
+ * @brief Enable SHI module.
+ *
+ * @param dev Pointer to the device structure for the driver instance.
+ *
+ * @retval non-negative if successful.
+ * @retval Negative errno code if failure.
+ */
+__syscall int cros_shi_enable(const struct device *dev);
+
+static inline int z_impl_cros_shi_enable(const struct device *dev)
+{
+	const struct cros_shi_driver_api *api =
+		(const struct cros_shi_driver_api *)dev->api;
+
+	if (!api->enable) {
+		return -ENOTSUP;
+	}
+
+	return api->enable(dev);
+}
+
+/**
+ * @brief Disable SHI module.
+ *
+ * @param dev Pointer to the device structure for the driver instance.
+ *
+ * @retval no return if successful.
+ * @retval Negative errno code if failure.
+ */
+__syscall int cros_shi_disable(const struct device *dev);
+
+static inline int z_impl_cros_shi_disable(const struct device *dev)
+{
+	const struct cros_shi_driver_api *api =
+		(const struct cros_shi_driver_api *)dev->api;
+
+	if (!api->disable) {
+		return -ENOTSUP;
+	}
+
+	return api->disable(dev);
+}
+
+/**
+ * @}
+ */
+#include <syscalls/cros_shi.h>
+#endif /* ZEPHYR_INCLUDE_DRIVERS_CROS_SHI_H_ */