[v2,1/3] media: pci: intel: ivsc: Add CSI submodule

diff --git a/drivers/media/pci/Kconfig b/drivers/media/pci/Kconfig
index 1224d908713a..16661ab0b816 100644
--- a/drivers/media/pci/Kconfig
+++ b/drivers/media/pci/Kconfig
@@ -74,6 +74,7 @@  config VIDEO_PCI_SKELETON
 	  when developing new drivers.
 
 source "drivers/media/pci/intel/ipu3/Kconfig"
+source "drivers/media/pci/intel/ivsc/Kconfig"
 
 endif #MEDIA_PCI_SUPPORT
 endif #PCI
diff --git a/drivers/media/pci/intel/Makefile b/drivers/media/pci/intel/Makefile
index 0b4236c4db49..d27ca636c860 100644
--- a/drivers/media/pci/intel/Makefile
+++ b/drivers/media/pci/intel/Makefile
@@ -4,3 +4,5 @@ 
 #
 
 obj-y	+= ipu3/
+
+obj-$(CONFIG_INTEL_VSC) += ivsc/
diff --git a/drivers/media/pci/intel/ivsc/Kconfig b/drivers/media/pci/intel/ivsc/Kconfig
new file mode 100644
index 000000000000..9535ac10f4f7
--- /dev/null
+++ b/drivers/media/pci/intel/ivsc/Kconfig
@@ -0,0 +1,12 @@ 
+# SPDX-License-Identifier: GPL-2.0-only
+# Copyright (C) 2023, Intel Corporation. All rights reserved.
+
+config INTEL_VSC
+	tristate "Intel Visual Sensing Controller"
+	depends on INTEL_MEI
+	help
+	  This adds support for Intel Visual Sensing Controller (IVSC).
+
+	  Enables the IVSC firmware services required for controlling
+	  camera sensor ownership and CSI-2 link through Image Processing
+	  Unit(IPU) driver of Intel.
diff --git a/drivers/media/pci/intel/ivsc/Makefile b/drivers/media/pci/intel/ivsc/Makefile
new file mode 100644
index 000000000000..1825aad45cff
--- /dev/null
+++ b/drivers/media/pci/intel/ivsc/Makefile
@@ -0,0 +1,5 @@ 
+# SPDX-License-Identifier: GPL-2.0-only
+#
+# Copyright (C) 2023, Intel Corporation. All rights reserved.
+
+obj-$(CONFIG_INTEL_VSC) += mei_csi.o
diff --git a/drivers/media/pci/intel/ivsc/mei_csi.c b/drivers/media/pci/intel/ivsc/mei_csi.c
new file mode 100644
index 000000000000..309e52387502
--- /dev/null
+++ b/drivers/media/pci/intel/ivsc/mei_csi.c
@@ -0,0 +1,342 @@ 
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (C) 2023 Intel Corporation. All rights reserved.
+ * Intel Visual Sensing Controller CSI Linux driver
+ */
+
+/*
+ * To set ownership of CSI-2 link and to configure CSI-2 link, there
+ * are specific commands, which are sent via MEI protocol. The send
+ * command function uses "completion" as a synchronization mechanism.
+ * The response for command is received via a mei callback which wakes
+ * up the caller. There can be only one outstanding command at a time.
+ */
+
+#include <linux/completion.h>
+#include <linux/delay.h>
+#include <linux/kernel.h>
+#include <linux/math64.h>
+#include <linux/mei_cl_bus.h>
+#include <linux/module.h>
+#include <linux/mutex.h>
+#include <linux/slab.h>
+#include <linux/units.h>
+#include <linux/uuid.h>
+#include <linux/workqueue.h>
+
+#include "mei_csi.h"
+
+#define MEI_CSI_DRIVER_NAME "ivsc_csi"
+
+/* the 5s used here is based on experiment */
+#define CSI_CMD_TIMEOUT (5 * HZ)
+/* to setup CSI-2 link an extra delay needed and determined experimentally */
+#define CSI_FW_READY_DELAY_MS 100
+/* link frequency unit is 100kHz */
+#define CSI_LINK_FREQ(x) ((u32)(div_u64(x, 100 * HZ_PER_KHZ)))
+
+/*
+ * identify the command id supported by firmware
+ * IPC, as well as the privacy notification id
+ * used when processing privacy event.
+ */
+enum csi_cmd_id {
+	/* used to set csi ownership */
+	CSI_SET_OWNER = 0,
+
+	/* used to configure CSI-2 link */
+	CSI_SET_CONF = 2,
+
+	/* privacy notification id used when privacy state changes */
+	CSI_PRIVACY_NOTIF = 6,
+};
+
+/* configuration of the CSI-2 link between host and IVSC */
+struct csi_link_cfg {
+	/* number of data lanes used on the CSI-2 link */
+	u32 nr_of_lanes;
+
+	/* frequency of the CSI-2 link */
+	u32 link_freq;
+
+	/* for future use */
+	u32 rsvd[2];
+} __packed;
+
+/* CSI command structure */
+struct csi_cmd {
+	u32 cmd_id;
+	union _cmd_param {
+		u32 param;
+		struct csi_link_cfg conf;
+	} param;
+} __packed;
+
+/* CSI notification structure */
+struct csi_notif {
+	u32 cmd_id;
+	int status;
+	union _resp_cont {
+		u32 cont;
+		struct csi_link_cfg conf;
+	} cont;
+} __packed;
+
+struct mei_csi {
+	struct mei_cl_device *cldev;
+
+	/* command response */
+	struct csi_notif cmd_response;
+	/* used to wait for command response from firmware */
+	struct completion cmd_completion;
+
+	/* work element used to handle firmware event */
+	struct work_struct event_work;
+
+	/* privacy status */
+	enum ivsc_privacy_status status;
+	/* privacy callback */
+	void (*callback)(void *, enum ivsc_privacy_status);
+	/* privacy callback runtime context */
+	void *context;
+};
+
+/* only one for now */
+static struct mei_csi *csi;
+/* lock used to prevent multiple call to csi */
+static DEFINE_MUTEX(csi_mutex);
+
+/* send a command to firmware and mutex must be held by caller */
+static int mei_csi_send(u8 *buf, size_t len)
+{
+	struct csi_cmd *cmd = (struct csi_cmd *)buf;
+	int ret;
+
+	reinit_completion(&csi->cmd_completion);
+
+	ret = mei_cldev_send(csi->cldev, buf, len);
+	if (ret < 0)
+		goto out;
+
+	ret = wait_for_completion_killable_timeout(&csi->cmd_completion,
+						   CSI_CMD_TIMEOUT);
+	if (ret < 0) {
+		goto out;
+	} else if (!ret) {
+		ret = -ETIMEDOUT;
+		goto out;
+	}
+
+	/* command response status */
+	ret = csi->cmd_response.status;
+	if (ret) {
+		ret = -EINVAL;
+		goto out;
+	}
+
+	if (csi->cmd_response.cmd_id != cmd->cmd_id)
+		ret = -EINVAL;
+
+out:
+	return ret;
+}
+
+int csi_set_link_owner(enum csi_link_owner owner,
+		       void (*callback)(void *, enum ivsc_privacy_status),
+		       void *context)
+{
+	struct csi_cmd cmd = { 0 };
+	size_t cmd_size;
+	int ret;
+
+	cmd.cmd_id = CSI_SET_OWNER;
+	cmd.param.param = owner;
+	cmd_size = sizeof(cmd.cmd_id) + sizeof(cmd.param.param);
+
+	mutex_lock(&csi_mutex);
+	if (unlikely(!csi)) {
+		mutex_unlock(&csi_mutex);
+		return -EAGAIN;
+	}
+
+	ret = mei_csi_send((u8 *)&cmd, cmd_size);
+
+	/*
+	 * cancel possible event work and wait for it to finish
+	 * to make sure no work running for the ongoing changes
+	 * to callback and context.
+	 */
+	cancel_work_sync(&csi->event_work);
+	csi->callback = callback;
+	csi->context = context;
+	mutex_unlock(&csi_mutex);
+
+	return ret;
+}
+EXPORT_SYMBOL_NS_GPL(csi_set_link_owner, IVSC);
+
+int csi_set_link_cfg(u32 nr_of_lanes, u64 link_freq)
+{
+	struct csi_cmd cmd = { 0 };
+	size_t cmd_size;
+	int ret;
+
+	cmd.cmd_id = CSI_SET_CONF;
+	cmd.param.conf.nr_of_lanes = nr_of_lanes;
+	cmd.param.conf.link_freq = CSI_LINK_FREQ(link_freq);
+	cmd_size = sizeof(cmd.cmd_id) + sizeof(cmd.param.conf);
+
+	mutex_lock(&csi_mutex);
+	if (unlikely(!csi)) {
+		mutex_unlock(&csi_mutex);
+		return -EAGAIN;
+	}
+
+	ret = mei_csi_send((u8 *)&cmd, cmd_size);
+	/*
+	 * wait configuration ready if download success. placing
+	 * delay under mutex is to make sure current command flow
+	 * completed before starting a possible new one.
+	 */
+	if (!ret)
+		msleep(CSI_FW_READY_DELAY_MS);
+	mutex_unlock(&csi_mutex);
+
+	return ret;
+}
+EXPORT_SYMBOL_NS_GPL(csi_set_link_cfg, IVSC);
+
+/* event handling routine */
+static void mei_csi_event_work(struct work_struct *work)
+{
+	if (csi->callback)
+		csi->callback(csi->context, READ_ONCE(csi->status));
+}
+
+/* callback for receive */
+static void mei_csi_rx(struct mei_cl_device *cldev)
+{
+	struct csi_notif notif = { 0 };
+	int ret;
+
+	ret = mei_cldev_recv(cldev, (u8 *)&notif, sizeof(notif));
+	if (ret < 0) {
+		dev_err(&cldev->dev, "recv error: %d\n", ret);
+		return;
+	}
+
+	switch (notif.cmd_id) {
+	case CSI_PRIVACY_NOTIF:
+		if (notif.cont.cont < IVSC_PRIVACY_MAX) {
+			WRITE_ONCE(csi->status, notif.cont.cont);
+
+			schedule_work(&csi->event_work);
+		}
+		break;
+	case CSI_SET_OWNER:
+	case CSI_SET_CONF:
+		memcpy(&csi->cmd_response, &notif, ret);
+
+		complete(&csi->cmd_completion);
+		break;
+	default:
+		break;
+	}
+}
+
+static int mei_csi_probe(struct mei_cl_device *cldev,
+			 const struct mei_cl_device_id *id)
+{
+	int ret;
+
+	mutex_lock(&csi_mutex);
+	/*
+	 * only instance is possible in the current hardware,
+	 * but adding protection for future hardware.
+	 */
+	if (csi) {
+		ret = -EBUSY;
+		goto err_unlock;
+	}
+
+	csi = kzalloc(sizeof(*csi), GFP_KERNEL);
+	if (!csi) {
+		ret = -ENOMEM;
+		goto err_unlock;
+	}
+
+	csi->cldev = cldev;
+	init_completion(&csi->cmd_completion);
+	INIT_WORK(&csi->event_work, mei_csi_event_work);
+
+	mei_cldev_set_drvdata(cldev, csi);
+
+	ret = mei_cldev_enable(cldev);
+	if (ret < 0) {
+		dev_err(&cldev->dev, "mei_cldev_enable failed: %d\n", ret);
+		goto err_free;
+	}
+
+	ret = mei_cldev_register_rx_cb(cldev, mei_csi_rx);
+	if (ret) {
+		dev_err(&cldev->dev, "event cb registration failed: %d\n", ret);
+		goto err_disable;
+	}
+	mutex_unlock(&csi_mutex);
+
+	return 0;
+
+err_disable:
+	mei_cldev_disable(cldev);
+
+err_free:
+	kfree(csi);
+	/* disable csi */
+	csi = NULL;
+
+err_unlock:
+	mutex_unlock(&csi_mutex);
+
+	return ret;
+}
+
+static void mei_csi_remove(struct mei_cl_device *cldev)
+{
+	mutex_lock(&csi_mutex);
+	/* disable mei csi client device */
+	mei_cldev_disable(cldev);
+
+	/* cancel event work and wait for it to finish */
+	cancel_work_sync(&csi->event_work);
+
+	kfree(csi);
+	/* disable csi */
+	csi = NULL;
+	mutex_unlock(&csi_mutex);
+}
+
+#define MEI_CSI_UUID UUID_LE(0x92335FCF, 0x3203, 0x4472, \
+			     0xAF, 0x93, 0x7b, 0x44, 0x53, 0xAC, 0x29, 0xDA)
+
+static const struct mei_cl_device_id mei_csi_tbl[] = {
+	{ MEI_CSI_DRIVER_NAME, MEI_CSI_UUID, MEI_CL_VERSION_ANY },
+
+	/* required last entry */
+	{ }
+};
+MODULE_DEVICE_TABLE(mei, mei_csi_tbl);
+
+static struct mei_cl_driver mei_csi_driver = {
+	.id_table = mei_csi_tbl,
+	.name = MEI_CSI_DRIVER_NAME,
+
+	.probe = mei_csi_probe,
+	.remove = mei_csi_remove,
+};
+
+module_mei_cl_driver(mei_csi_driver);
+
+MODULE_AUTHOR("Wentong Wu <wentong.wu@intel.com>");
+MODULE_AUTHOR("Zhifeng Wang <zhifeng.wang@intel.com>");
+MODULE_DESCRIPTION("Device driver for IVSC CSI");
+MODULE_LICENSE("GPL");
diff --git a/drivers/media/pci/intel/ivsc/mei_csi.h b/drivers/media/pci/intel/ivsc/mei_csi.h
new file mode 100644
index 000000000000..0cc51e6a5250
--- /dev/null
+++ b/drivers/media/pci/intel/ivsc/mei_csi.h
@@ -0,0 +1,60 @@ 
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * Copyright (C) 2023 Intel Corporation. All rights reserved.
+ * Intel Visual Sensing Controller CSI external interface
+ */
+
+#ifndef _MEI_CSI_H_
+#define _MEI_CSI_H_
+
+#include <linux/ivsc.h>
+
+/* CSI-2 link ownership definition */
+enum csi_link_owner {
+	CSI_LINK_IVSC,
+	CSI_LINK_HOST,
+};
+
+#if IS_ENABLED(CONFIG_INTEL_VSC)
+/*
+ * @brief set CSI-2 link ownership
+ *
+ * @param owner The csi ownership being set
+ * @param callback The pointer of privacy callback being set
+ * @param context Privacy callback runtime context
+ *
+ * @return 0 on success, negative on failure
+ */
+int csi_set_link_owner(enum csi_link_owner owner,
+		       void (*callback)(void *, enum ivsc_privacy_status),
+		       void *context);
+
+/*
+ * @brief configure CSI-2 link between host and IVSC
+ * with provided parameters
+ *
+ * @param nr_of_lanes The number of data lanes being used
+ * on the CSI-2 link
+ * @param link_freq The frequency being set on the CSI-2 link
+ *
+ * @return 0 on success, negative on failure
+ */
+int csi_set_link_cfg(u32 nr_of_lanes, u64 link_freq);
+
+#else
+static inline
+int csi_set_link_owner(enum csi_link_owner owner,
+		       void (*callback)(void *, enum ivsc_privacy_status),
+		       void *context)
+{
+	return 0;
+}
+
+static inline int csi_set_link_cfg(u32 nr_of_lanes, u64 link_freq)
+{
+	return 0;
+}
+
+#endif
+
+#endif
diff --git a/include/linux/ivsc.h b/include/linux/ivsc.h
new file mode 100644
index 000000000000..6572ca4f340c
--- /dev/null
+++ b/include/linux/ivsc.h
@@ -0,0 +1,19 @@ 
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * Copyright (C) 2023 Intel Corporation. All rights reserved.
+ * Intel Visual Sensing Controller interface
+ */
+
+#ifndef _LINUX_IVSC_H_
+#define _LINUX_IVSC_H_
+
+#include <linux/types.h>
+
+/* IVSC privacy status definition */
+enum ivsc_privacy_status {
+	IVSC_PRIVACY_OFF,
+	IVSC_PRIVACY_ON,
+	IVSC_PRIVACY_MAX,
+};
+
+#endif