1 files changed, 579 insertions, 0 deletions
diff --git a/drivers/media/pci/intel/ivsc/mei_ace.c b/drivers/media/pci/intel/ivsc/mei_ace.c
new file mode 100644
index 000000000000..a0491f307831
--- /dev/null
+++ b/drivers/media/pci/intel/ivsc/mei_ace.c
@@ -0,0 +1,579 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (C) 2023 Intel Corporation. All rights reserved.
+ * Intel Visual Sensing Controller ACE Linux driver
+ */
+
+/*
+ * To set ownership of camera sensor, there is specific command, which
+ * is sent via MEI protocol. That's a two-step scheme where the firmware
+ * first acks receipt of the command and later responses the command was
+ * executed. The command sending function uses "completion" as the
+ * synchronization mechanism. The notification for command is received
+ * via a mei callback which wakes up the caller. There can be only one
+ * outstanding command at a time.
+ *
+ * The power line of camera sensor is directly connected to IVSC instead
+ * of host, when camera sensor ownership is switched to host, sensor is
+ * already powered up by firmware.
+ */
+
+#include <linux/acpi.h>
+#include <linux/completion.h>
+#include <linux/delay.h>
+#include <linux/kernel.h>
+#include <linux/mei_cl_bus.h>
+#include <linux/module.h>
+#include <linux/mutex.h>
+#include <linux/pm_runtime.h>
+#include <linux/slab.h>
+#include <linux/uuid.h>
+#include <linux/workqueue.h>
+
+#define	MEI_ACE_DRIVER_NAME	"ivsc_ace"
+
+/* indicating driver message */
+#define	ACE_DRV_MSG		1
+/* indicating set command */
+#define	ACE_CMD_SET		4
+/* command timeout determined experimentally */
+#define	ACE_CMD_TIMEOUT		(5 * HZ)
+/* indicating the first command block */
+#define	ACE_CMD_INIT_BLOCK	1
+/* indicating the last command block */
+#define	ACE_CMD_FINAL_BLOCK	1
+/* size of camera status notification content */
+#define	ACE_CAMERA_STATUS_SIZE	5
+
+/* UUID used to get firmware id */
+#define ACE_GET_FW_ID_UUID UUID_LE(0x6167DCFB, 0x72F1, 0x4584, 0xBF, \
+				   0xE3, 0x84, 0x17, 0x71, 0xAA, 0x79, 0x0B)
+
+/* UUID used to get csi device */
+#define MEI_CSI_UUID UUID_LE(0x92335FCF, 0x3203, 0x4472, \
+			     0xAF, 0x93, 0x7b, 0x44, 0x53, 0xAC, 0x29, 0xDA)
+
+/* identify firmware event type */
+enum ace_event_type {
+	/* firmware ready */
+	ACE_FW_READY = 0x8,
+
+	/* command response */
+	ACE_CMD_RESPONSE = 0x10,
+};
+
+/* identify camera sensor ownership */
+enum ace_camera_owner {
+	ACE_CAMERA_IVSC,
+	ACE_CAMERA_HOST,
+};
+
+/* identify the command id supported by firmware IPC */
+enum ace_cmd_id {
+	/* used to switch camera sensor to host */
+	ACE_SWITCH_CAMERA_TO_HOST = 0x13,
+
+	/* used to switch camera sensor to IVSC */
+	ACE_SWITCH_CAMERA_TO_IVSC = 0x14,
+
+	/* used to get firmware id */
+	ACE_GET_FW_ID = 0x1A,
+};
+
+/* ACE command header structure */
+struct ace_cmd_hdr {
+	u32 firmware_id : 16;
+	u32 instance_id : 8;
+	u32 type : 5;
+	u32 rsp : 1;
+	u32 msg_tgt : 1;
+	u32 _hw_rsvd_1 : 1;
+	u32 param_size : 20;
+	u32 cmd_id : 8;
+	u32 final_block : 1;
+	u32 init_block : 1;
+	u32 _hw_rsvd_2 : 2;
+} __packed;
+
+/* ACE command parameter structure */
+union ace_cmd_param {
+	uuid_le uuid;
+	u32 param;
+};
+
+/* ACE command structure */
+struct ace_cmd {
+	struct ace_cmd_hdr hdr;
+	union ace_cmd_param param;
+} __packed;
+
+/* ACE notification header */
+union ace_notif_hdr {
+	struct _confirm {
+		u32 status : 24;
+		u32 type : 5;
+		u32 rsp : 1;
+		u32 msg_tgt : 1;
+		u32 _hw_rsvd_1 : 1;
+		u32 param_size : 20;
+		u32 cmd_id : 8;
+		u32 final_block : 1;
+		u32 init_block : 1;
+		u32 _hw_rsvd_2 : 2;
+	} __packed ack;
+
+	struct _event {
+		u32 rsvd1 : 16;
+		u32 event_type : 8;
+		u32 type : 5;
+		u32 ack : 1;
+		u32 msg_tgt : 1;
+		u32 _hw_rsvd_1 : 1;
+		u32 rsvd2 : 30;
+		u32 _hw_rsvd_2 : 2;
+	} __packed event;
+
+	struct _response {
+		u32 event_id : 16;
+		u32 notif_type : 8;
+		u32 type : 5;
+		u32 rsp : 1;
+		u32 msg_tgt : 1;
+		u32 _hw_rsvd_1 : 1;
+		u32 event_data_size : 16;
+		u32 request_target : 1;
+		u32 request_type : 5;
+		u32 cmd_id : 8;
+		u32 _hw_rsvd_2 : 2;
+	} __packed response;
+};
+
+/* ACE notification content */
+union ace_notif_cont {
+	u16 firmware_id;
+	u8 state_notif;
+	u8 camera_status[ACE_CAMERA_STATUS_SIZE];
+};
+
+/* ACE notification structure */
+struct ace_notif {
+	union ace_notif_hdr hdr;
+	union ace_notif_cont cont;
+} __packed;
+
+struct mei_ace {
+	struct mei_cl_device *cldev;
+
+	/* command ack */
+	struct ace_notif cmd_ack;
+	/* command response */
+	struct ace_notif cmd_response;
+	/* used to wait for command ack and response */
+	struct completion cmd_completion;
+	/* lock used to prevent multiple call to send command */
+	struct mutex lock;
+
+	/* used to construct command */
+	u16 firmware_id;
+
+	struct device *csi_dev;
+
+	/* runtime PM link from ace to csi */
+	struct device_link *csi_link;
+
+	struct work_struct work;
+};
+
+static inline void init_cmd_hdr(struct ace_cmd_hdr *hdr)
+{
+	memset(hdr, 0, sizeof(struct ace_cmd_hdr));
+
+	hdr->type = ACE_CMD_SET;
+	hdr->msg_tgt = ACE_DRV_MSG;
+	hdr->init_block = ACE_CMD_INIT_BLOCK;
+	hdr->final_block = ACE_CMD_FINAL_BLOCK;
+}
+
+static int construct_command(struct mei_ace *ace, struct ace_cmd *cmd,
+			     enum ace_cmd_id cmd_id)
+{
+	union ace_cmd_param *param = &cmd->param;
+	struct ace_cmd_hdr *hdr = &cmd->hdr;
+
+	init_cmd_hdr(hdr);
+
+	hdr->cmd_id = cmd_id;
+	switch (cmd_id) {
+	case ACE_GET_FW_ID:
+		param->uuid = ACE_GET_FW_ID_UUID;
+		hdr->param_size = sizeof(param->uuid);
+		break;
+	case ACE_SWITCH_CAMERA_TO_IVSC:
+		param->param = 0;
+		hdr->firmware_id = ace->firmware_id;
+		hdr->param_size = sizeof(param->param);
+		break;
+	case ACE_SWITCH_CAMERA_TO_HOST:
+		hdr->firmware_id = ace->firmware_id;
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	return hdr->param_size + sizeof(cmd->hdr);
+}
+
+/* send command to firmware */
+static int mei_ace_send(struct mei_ace *ace, struct ace_cmd *cmd,
+			size_t len, bool only_ack)
+{
+	union ace_notif_hdr *resp_hdr = &ace->cmd_response.hdr;
+	union ace_notif_hdr *ack_hdr = &ace->cmd_ack.hdr;
+	struct ace_cmd_hdr *cmd_hdr = &cmd->hdr;
+	int ret;
+
+	mutex_lock(&ace->lock);
+
+	reinit_completion(&ace->cmd_completion);
+
+	ret = mei_cldev_send(ace->cldev, (u8 *)cmd, len);
+	if (ret < 0)
+		goto out;
+
+	ret = wait_for_completion_killable_timeout(&ace->cmd_completion,
+						   ACE_CMD_TIMEOUT);
+	if (ret < 0) {
+		goto out;
+	} else if (!ret) {
+		ret = -ETIMEDOUT;
+		goto out;
+	}
+
+	if (ack_hdr->ack.cmd_id != cmd_hdr->cmd_id) {
+		ret = -EINVAL;
+		goto out;
+	}
+
+	/* command ack status */
+	ret = ack_hdr->ack.status;
+	if (ret) {
+		ret = -EIO;
+		goto out;
+	}
+
+	if (only_ack)
+		goto out;
+
+	ret = wait_for_completion_killable_timeout(&ace->cmd_completion,
+						   ACE_CMD_TIMEOUT);
+	if (ret < 0) {
+		goto out;
+	} else if (!ret) {
+		ret = -ETIMEDOUT;
+		goto out;
+	} else {
+		ret = 0;
+	}
+
+	if (resp_hdr->response.cmd_id != cmd_hdr->cmd_id)
+		ret = -EINVAL;
+
+out:
+	mutex_unlock(&ace->lock);
+
+	return ret;
+}
+
+static int ace_set_camera_owner(struct mei_ace *ace,
+				enum ace_camera_owner owner)
+{
+	enum ace_cmd_id cmd_id;
+	struct ace_cmd cmd;
+	int cmd_size;
+	int ret;
+
+	if (owner == ACE_CAMERA_IVSC)
+		cmd_id = ACE_SWITCH_CAMERA_TO_IVSC;
+	else
+		cmd_id = ACE_SWITCH_CAMERA_TO_HOST;
+
+	cmd_size = construct_command(ace, &cmd, cmd_id);
+	if (cmd_size >= 0)
+		ret = mei_ace_send(ace, &cmd, cmd_size, false);
+	else
+		ret = cmd_size;
+
+	return ret;
+}
+
+/* the first command downloaded to firmware */
+static inline int ace_get_firmware_id(struct mei_ace *ace)
+{
+	struct ace_cmd cmd;
+	int cmd_size;
+	int ret;
+
+	cmd_size = construct_command(ace, &cmd, ACE_GET_FW_ID);
+	if (cmd_size >= 0)
+		ret = mei_ace_send(ace, &cmd, cmd_size, true);
+	else
+		ret = cmd_size;
+
+	return ret;
+}
+
+static void handle_command_response(struct mei_ace *ace,
+				    struct ace_notif *resp, int len)
+{
+	union ace_notif_hdr *hdr = &resp->hdr;
+
+	switch (hdr->response.cmd_id) {
+	case ACE_SWITCH_CAMERA_TO_IVSC:
+	case ACE_SWITCH_CAMERA_TO_HOST:
+		memcpy(&ace->cmd_response, resp, len);
+		complete(&ace->cmd_completion);
+		break;
+	case ACE_GET_FW_ID:
+		break;
+	default:
+		break;
+	}
+}
+
+static void handle_command_ack(struct mei_ace *ace,
+			       struct ace_notif *ack, int len)
+{
+	union ace_notif_hdr *hdr = &ack->hdr;
+
+	switch (hdr->ack.cmd_id) {
+	case ACE_GET_FW_ID:
+		ace->firmware_id = ack->cont.firmware_id;
+		fallthrough;
+	case ACE_SWITCH_CAMERA_TO_IVSC:
+	case ACE_SWITCH_CAMERA_TO_HOST:
+		memcpy(&ace->cmd_ack, ack, len);
+		complete(&ace->cmd_completion);
+		break;
+	default:
+		break;
+	}
+}
+
+/* callback for receive */
+static void mei_ace_rx(struct mei_cl_device *cldev)
+{
+	struct mei_ace *ace = mei_cldev_get_drvdata(cldev);
+	struct ace_notif event;
+	union ace_notif_hdr *hdr = &event.hdr;
+	int ret;
+
+	ret = mei_cldev_recv(cldev, (u8 *)&event, sizeof(event));
+	if (ret < 0) {
+		dev_err(&cldev->dev, "recv error: %d\n", ret);
+		return;
+	}
+
+	if (hdr->event.ack) {
+		handle_command_ack(ace, &event, ret);
+		return;
+	}
+
+	switch (hdr->event.event_type) {
+	case ACE_CMD_RESPONSE:
+		handle_command_response(ace, &event, ret);
+		break;
+	case ACE_FW_READY:
+		/*
+		 * firmware ready notification sent to driver
+		 * after HECI client connected with firmware.
+		 */
+		dev_dbg(&cldev->dev, "firmware ready\n");
+		break;
+	default:
+		break;
+	}
+}
+
+static int mei_ace_setup_dev_link(struct mei_ace *ace)
+{
+	struct device *dev = &ace->cldev->dev;
+	uuid_le uuid = MEI_CSI_UUID;
+	struct device *csi_dev;
+	char name[64];
+	int ret;
+
+	snprintf(name, sizeof(name), "%s-%pUl", dev_name(dev->parent), &uuid);
+
+	csi_dev = device_find_child_by_name(dev->parent, name);
+	if (!csi_dev) {
+		ret = -EPROBE_DEFER;
+		goto err;
+	}
+
+	/* setup link between mei_ace and mei_csi */
+	ace->csi_link = device_link_add(csi_dev, dev, DL_FLAG_PM_RUNTIME |
+					DL_FLAG_RPM_ACTIVE | DL_FLAG_STATELESS);
+	if (!ace->csi_link) {
+		ret = -EINVAL;
+		dev_err(dev, "failed to link to %s\n", dev_name(csi_dev));
+		goto err_put;
+	}
+
+	ace->csi_dev = csi_dev;
+
+	return 0;
+
+err_put:
+	put_device(csi_dev);
+
+err:
+	return ret;
+}
+
+/* switch camera to host before probe sensor device */
+static void mei_ace_post_probe_work(struct work_struct *work)
+{
+	struct acpi_device *adev;
+	struct mei_ace *ace;
+	struct device *dev;
+	int ret;
+
+	ace = container_of(work, struct mei_ace, work);
+	dev = &ace->cldev->dev;
+
+	ret = ace_set_camera_owner(ace, ACE_CAMERA_HOST);
+	if (ret) {
+		dev_err(dev, "switch camera to host failed: %d\n", ret);
+		return;
+	}
+
+	adev = ACPI_COMPANION(dev->parent);
+	if (!adev)
+		return;
+
+	acpi_dev_clear_dependencies(adev);
+}
+
+static int mei_ace_probe(struct mei_cl_device *cldev,
+			 const struct mei_cl_device_id *id)
+{
+	struct device *dev = &cldev->dev;
+	struct mei_ace *ace;
+	int ret;
+
+	ace = devm_kzalloc(dev, sizeof(struct mei_ace), GFP_KERNEL);
+	if (!ace)
+		return -ENOMEM;
+
+	ace->cldev = cldev;
+	mutex_init(&ace->lock);
+	init_completion(&ace->cmd_completion);
+	INIT_WORK(&ace->work, mei_ace_post_probe_work);
+
+	mei_cldev_set_drvdata(cldev, ace);
+
+	ret = mei_cldev_enable(cldev);
+	if (ret < 0) {
+		dev_err(dev, "mei_cldev_enable failed: %d\n", ret);
+		goto destroy_mutex;
+	}
+
+	ret = mei_cldev_register_rx_cb(cldev, mei_ace_rx);
+	if (ret) {
+		dev_err(dev, "event cb registration failed: %d\n", ret);
+		goto err_disable;
+	}
+
+	ret = ace_get_firmware_id(ace);
+	if (ret) {
+		dev_err(dev, "get firmware id failed: %d\n", ret);
+		goto err_disable;
+	}
+
+	pm_runtime_set_active(dev);
+	pm_runtime_enable(dev);
+
+	ret = mei_ace_setup_dev_link(ace);
+	if (ret)
+		goto disable_pm;
+
+	schedule_work(&ace->work);
+
+	return 0;
+
+disable_pm:
+	pm_runtime_disable(dev);
+	pm_runtime_set_suspended(dev);
+
+err_disable:
+	mei_cldev_disable(cldev);
+
+destroy_mutex:
+	mutex_destroy(&ace->lock);
+
+	return ret;
+}
+
+static void mei_ace_remove(struct mei_cl_device *cldev)
+{
+	struct mei_ace *ace = mei_cldev_get_drvdata(cldev);
+
+	cancel_work_sync(&ace->work);
+
+	device_link_del(ace->csi_link);
+	put_device(ace->csi_dev);
+
+	pm_runtime_disable(&cldev->dev);
+	pm_runtime_set_suspended(&cldev->dev);
+
+	ace_set_camera_owner(ace, ACE_CAMERA_IVSC);
+
+	mutex_destroy(&ace->lock);
+}
+
+static int __maybe_unused mei_ace_runtime_suspend(struct device *dev)
+{
+	struct mei_ace *ace = dev_get_drvdata(dev);
+
+	return ace_set_camera_owner(ace, ACE_CAMERA_IVSC);
+}
+
+static int __maybe_unused mei_ace_runtime_resume(struct device *dev)
+{
+	struct mei_ace *ace = dev_get_drvdata(dev);
+
+	return ace_set_camera_owner(ace, ACE_CAMERA_HOST);
+}
+
+static const struct dev_pm_ops mei_ace_pm_ops = {
+	SET_RUNTIME_PM_OPS(mei_ace_runtime_suspend,
+			   mei_ace_runtime_resume, NULL)
+};
+
+#define MEI_ACE_UUID UUID_LE(0x5DB76CF6, 0x0A68, 0x4ED6, \
+			     0x9B, 0x78, 0x03, 0x61, 0x63, 0x5E, 0x24, 0x47)
+
+static const struct mei_cl_device_id mei_ace_tbl[] = {
+	{ MEI_ACE_DRIVER_NAME, MEI_ACE_UUID, MEI_CL_VERSION_ANY },
+	{ /* sentinel */ }
+};
+MODULE_DEVICE_TABLE(mei, mei_ace_tbl);
+
+static struct mei_cl_driver mei_ace_driver = {
+	.id_table = mei_ace_tbl,
+	.name = MEI_ACE_DRIVER_NAME,
+
+	.probe = mei_ace_probe,
+	.remove = mei_ace_remove,
+
+	.driver = {
+		.pm = &mei_ace_pm_ops,
+	},
+};
+
+module_mei_cl_driver(mei_ace_driver);
+
+MODULE_AUTHOR("Wentong Wu <wentong.wu@intel.com>");
+MODULE_AUTHOR("Zhifeng Wang <zhifeng.wang@intel.com>");
+MODULE_DESCRIPTION("Device driver for IVSC ACE");
+MODULE_LICENSE("GPL");