linux-surface/patches/6.0/0004-ipts.patch

From 8f4c7d7e1c3614f7dbc5ee8aba92e88000fd4aad Mon Sep 17 00:00:00 2001
From: Dorian Stoll <dorian.stoll@tmsp.io>
Date: Thu, 30 Jul 2020 13:21:53 +0200
Subject: [PATCH] misc: mei: Add missing IPTS device IDs

Patchset: ipts
---
 drivers/misc/mei/hw-me-regs.h | 1 +
 drivers/misc/mei/pci-me.c     | 1 +
 2 files changed, 2 insertions(+)

diff --git a/drivers/misc/mei/hw-me-regs.h b/drivers/misc/mei/hw-me-regs.h
index 15e8e2b322b1..91587b808323 100644
--- a/drivers/misc/mei/hw-me-regs.h
+++ b/drivers/misc/mei/hw-me-regs.h
@@ -92,6 +92,7 @@
 #define MEI_DEV_ID_CDF        0x18D3  /* Cedar Fork */
 
 #define MEI_DEV_ID_ICP_LP     0x34E0  /* Ice Lake Point LP */
+#define MEI_DEV_ID_ICP_LP_3   0x34E4  /* Ice Lake Point LP 3 (iTouch) */
 #define MEI_DEV_ID_ICP_N      0x38E0  /* Ice Lake Point N */
 
 #define MEI_DEV_ID_JSP_N      0x4DE0  /* Jasper Lake Point N */
diff --git a/drivers/misc/mei/pci-me.c b/drivers/misc/mei/pci-me.c
index 5435604327a7..1165ee4f5928 100644
--- a/drivers/misc/mei/pci-me.c
+++ b/drivers/misc/mei/pci-me.c
@@ -97,6 +97,7 @@ static const struct pci_device_id mei_me_pci_tbl[] = {
 	{MEI_PCI_DEVICE(MEI_DEV_ID_CMP_H_3, MEI_ME_PCH8_ITOUCH_CFG)},
 
 	{MEI_PCI_DEVICE(MEI_DEV_ID_ICP_LP, MEI_ME_PCH12_CFG)},
+	{MEI_PCI_DEVICE(MEI_DEV_ID_ICP_LP_3, MEI_ME_PCH12_CFG)},
 	{MEI_PCI_DEVICE(MEI_DEV_ID_ICP_N, MEI_ME_PCH12_CFG)},
 
 	{MEI_PCI_DEVICE(MEI_DEV_ID_TGP_LP, MEI_ME_PCH15_CFG)},
-- 
2.38.1

From 3abd40f113583709382d83f8f0a1f73c8acfd4e5 Mon Sep 17 00:00:00 2001
From: Dorian Stoll <dorian.stoll@tmsp.io>
Date: Thu, 6 Aug 2020 11:20:41 +0200
Subject: [PATCH] misc: Add support for Intel Precise Touch & Stylus

Based on linux-surface/intel-precise-touch@3f362c

Signed-off-by: Dorian Stoll <dorian.stoll@tmsp.io>
Patchset: ipts
---
 drivers/misc/Kconfig          |   1 +
 drivers/misc/Makefile         |   3 +-
 drivers/misc/ipts/Kconfig     |  17 ++
 drivers/misc/ipts/Makefile    |  12 ++
 drivers/misc/ipts/context.h   |  47 +++++
 drivers/misc/ipts/control.c   | 113 +++++++++++
 drivers/misc/ipts/control.h   |  24 +++
 drivers/misc/ipts/mei.c       | 125 ++++++++++++
 drivers/misc/ipts/protocol.h  | 347 ++++++++++++++++++++++++++++++++++
 drivers/misc/ipts/receiver.c  | 224 ++++++++++++++++++++++
 drivers/misc/ipts/receiver.h  |  16 ++
 drivers/misc/ipts/resources.c | 128 +++++++++++++
 drivers/misc/ipts/resources.h |  17 ++
 drivers/misc/ipts/uapi.c      | 208 ++++++++++++++++++++
 drivers/misc/ipts/uapi.h      |  47 +++++
 15 files changed, 1328 insertions(+), 1 deletion(-)
 create mode 100644 drivers/misc/ipts/Kconfig
 create mode 100644 drivers/misc/ipts/Makefile
 create mode 100644 drivers/misc/ipts/context.h
 create mode 100644 drivers/misc/ipts/control.c
 create mode 100644 drivers/misc/ipts/control.h
 create mode 100644 drivers/misc/ipts/mei.c
 create mode 100644 drivers/misc/ipts/protocol.h
 create mode 100644 drivers/misc/ipts/receiver.c
 create mode 100644 drivers/misc/ipts/receiver.h
 create mode 100644 drivers/misc/ipts/resources.c
 create mode 100644 drivers/misc/ipts/resources.h
 create mode 100644 drivers/misc/ipts/uapi.c
 create mode 100644 drivers/misc/ipts/uapi.h

diff --git a/drivers/misc/Kconfig b/drivers/misc/Kconfig
index 94e9fb4cdd76..12230c71fcf3 100644
--- a/drivers/misc/Kconfig
+++ b/drivers/misc/Kconfig
@@ -513,4 +513,5 @@ source "drivers/misc/cardreader/Kconfig"
 source "drivers/misc/habanalabs/Kconfig"
 source "drivers/misc/uacce/Kconfig"
 source "drivers/misc/pvpanic/Kconfig"
+source "drivers/misc/ipts/Kconfig"
 endmenu
diff --git a/drivers/misc/Makefile b/drivers/misc/Makefile
index 2be8542616dd..9e1a97b8c57e 100644
--- a/drivers/misc/Makefile
+++ b/drivers/misc/Makefile
@@ -60,4 +60,5 @@ obj-$(CONFIG_XILINX_SDFEC)	+= xilinx_sdfec.o
 obj-$(CONFIG_HISI_HIKEY_USB)	+= hisi_hikey_usb.o
 obj-$(CONFIG_HI6421V600_IRQ)	+= hi6421v600-irq.o
 obj-$(CONFIG_OPEN_DICE)		+= open-dice.o
-obj-$(CONFIG_VCPU_STALL_DETECTOR)	+= vcpu_stall_detector.o
\ No newline at end of file
+obj-$(CONFIG_VCPU_STALL_DETECTOR)	+= vcpu_stall_detector.o
+obj-$(CONFIG_MISC_IPTS)		+= ipts/
diff --git a/drivers/misc/ipts/Kconfig b/drivers/misc/ipts/Kconfig
new file mode 100644
index 000000000000..83e2a930c396
--- /dev/null
+++ b/drivers/misc/ipts/Kconfig
@@ -0,0 +1,17 @@
+# SPDX-License-Identifier: GPL-2.0-or-later
+
+config MISC_IPTS
+	tristate "Intel Precise Touch & Stylus"
+	depends on INTEL_MEI
+	help
+	  Say Y here if your system has a touchscreen using Intels
+	  Precise Touch & Stylus (IPTS) technology.
+
+	  If unsure say N.
+
+	  To compile this driver as a module, choose M here: the
+	  module will be called ipts.
+
+	  Building this driver alone will not give you a working touchscreen.
+	  It only exposed a userspace API that can be used by a daemon to
+	  receive and process data from the touchscreen hardware.
diff --git a/drivers/misc/ipts/Makefile b/drivers/misc/ipts/Makefile
new file mode 100644
index 000000000000..8f58b9adbc94
--- /dev/null
+++ b/drivers/misc/ipts/Makefile
@@ -0,0 +1,12 @@
+# SPDX-License-Identifier: GPL-2.0-or-later
+#
+# Makefile for the IPTS touchscreen driver
+#
+
+obj-$(CONFIG_MISC_IPTS) += ipts.o
+ipts-objs := control.o
+ipts-objs += mei.o
+ipts-objs += receiver.o
+ipts-objs += resources.o
+ipts-objs += uapi.o
+
diff --git a/drivers/misc/ipts/context.h b/drivers/misc/ipts/context.h
new file mode 100644
index 000000000000..f4b06a2d3f72
--- /dev/null
+++ b/drivers/misc/ipts/context.h
@@ -0,0 +1,47 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/*
+ * Copyright (c) 2016 Intel Corporation
+ * Copyright (c) 2020 Dorian Stoll
+ *
+ * Linux driver for Intel Precise Touch & Stylus
+ */
+
+#ifndef _IPTS_CONTEXT_H_
+#define _IPTS_CONTEXT_H_
+
+#include <linux/cdev.h>
+#include <linux/device.h>
+#include <linux/mei_cl_bus.h>
+#include <linux/types.h>
+
+#include "protocol.h"
+
+enum ipts_host_status {
+	IPTS_HOST_STATUS_STARTING,
+	IPTS_HOST_STATUS_STARTED,
+	IPTS_HOST_STATUS_STOPPING,
+	IPTS_HOST_STATUS_STOPPED,
+};
+
+struct ipts_buffer_info {
+	u8 *address;
+	dma_addr_t dma_address;
+};
+
+struct ipts_context {
+	struct mei_cl_device *cldev;
+	struct device *dev;
+
+	bool restart;
+	enum ipts_host_status status;
+	struct ipts_get_device_info_rsp device_info;
+
+	struct ipts_buffer_info data[IPTS_BUFFERS];
+	struct ipts_buffer_info doorbell;
+
+	struct ipts_buffer_info feedback[IPTS_BUFFERS];
+	struct ipts_buffer_info workqueue;
+	struct ipts_buffer_info host2me;
+};
+
+#endif /* _IPTS_CONTEXT_H_ */
diff --git a/drivers/misc/ipts/control.c b/drivers/misc/ipts/control.c
new file mode 100644
index 000000000000..a1d1f97a13d7
--- /dev/null
+++ b/drivers/misc/ipts/control.c
@@ -0,0 +1,113 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Copyright (c) 2016 Intel Corporation
+ * Copyright (c) 2020 Dorian Stoll
+ *
+ * Linux driver for Intel Precise Touch & Stylus
+ */
+
+#include <linux/mei_cl_bus.h>
+
+#include "context.h"
+#include "protocol.h"
+#include "resources.h"
+#include "uapi.h"
+
+int ipts_control_send(struct ipts_context *ipts, u32 code, void *payload,
+		      size_t size)
+{
+	int ret;
+	struct ipts_command cmd;
+
+	memset(&cmd, 0, sizeof(struct ipts_command));
+	cmd.code = code;
+
+	if (payload && size > 0)
+		memcpy(&cmd.payload, payload, size);
+
+	ret = mei_cldev_send(ipts->cldev, (u8 *)&cmd, sizeof(cmd.code) + size);
+	if (ret >= 0)
+		return 0;
+
+	/*
+	 * During shutdown the device might get pulled away from below our feet.
+	 * Dont log an error in this case, because it will confuse people.
+	 */
+	if (ret != -ENODEV || ipts->status != IPTS_HOST_STATUS_STOPPING)
+		dev_err(ipts->dev, "Error while sending: 0x%X:%d\n", code, ret);
+
+	return ret;
+}
+
+int ipts_control_send_feedback(struct ipts_context *ipts, u32 buffer)
+{
+	struct ipts_feedback_cmd cmd;
+
+	memset(&cmd, 0, sizeof(struct ipts_feedback_cmd));
+	cmd.buffer = buffer;
+
+	return ipts_control_send(ipts, IPTS_CMD_FEEDBACK, &cmd,
+				 sizeof(struct ipts_feedback_cmd));
+}
+
+int ipts_control_set_feature(struct ipts_context *ipts, u8 report, u8 value)
+{
+	struct ipts_feedback_buffer *feedback;
+
+	memset(ipts->host2me.address, 0, ipts->device_info.feedback_size);
+	feedback = (struct ipts_feedback_buffer *)ipts->host2me.address;
+
+	feedback->cmd_type = IPTS_FEEDBACK_CMD_TYPE_NONE;
+	feedback->data_type = IPTS_FEEDBACK_DATA_TYPE_SET_FEATURES;
+	feedback->buffer = IPTS_HOST2ME_BUFFER;
+	feedback->size = 2;
+	feedback->payload[0] = report;
+	feedback->payload[1] = value;
+
+	return ipts_control_send_feedback(ipts, IPTS_HOST2ME_BUFFER);
+}
+
+int ipts_control_start(struct ipts_context *ipts)
+{
+	if (ipts->status != IPTS_HOST_STATUS_STOPPED)
+		return -EBUSY;
+
+	dev_info(ipts->dev, "Starting IPTS\n");
+	ipts->status = IPTS_HOST_STATUS_STARTING;
+	ipts->restart = false;
+
+	ipts_uapi_link(ipts);
+	return ipts_control_send(ipts, IPTS_CMD_GET_DEVICE_INFO, NULL, 0);
+}
+
+int ipts_control_stop(struct ipts_context *ipts)
+{
+	int ret;
+
+	if (ipts->status == IPTS_HOST_STATUS_STOPPING)
+		return -EBUSY;
+
+	if (ipts->status == IPTS_HOST_STATUS_STOPPED)
+		return -EBUSY;
+
+	dev_info(ipts->dev, "Stopping IPTS\n");
+	ipts->status = IPTS_HOST_STATUS_STOPPING;
+
+	ipts_uapi_unlink();
+	ipts_resources_free(ipts);
+
+	ret = ipts_control_send_feedback(ipts, 0);
+	if (ret == -ENODEV)
+		ipts->status = IPTS_HOST_STATUS_STOPPED;
+
+	return ret;
+}
+
+int ipts_control_restart(struct ipts_context *ipts)
+{
+	if (ipts->restart)
+		return -EBUSY;
+
+	ipts->restart = true;
+	return ipts_control_stop(ipts);
+}
diff --git a/drivers/misc/ipts/control.h b/drivers/misc/ipts/control.h
new file mode 100644
index 000000000000..2c44e9e0e99f
--- /dev/null
+++ b/drivers/misc/ipts/control.h
@@ -0,0 +1,24 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/*
+ * Copyright (c) 2016 Intel Corporation
+ * Copyright (c) 2020 Dorian Stoll
+ *
+ * Linux driver for Intel Precise Touch & Stylus
+ */
+
+#ifndef _IPTS_CONTROL_H_
+#define _IPTS_CONTROL_H_
+
+#include <linux/types.h>
+
+#include "context.h"
+
+int ipts_control_send(struct ipts_context *ipts, u32 cmd, void *payload,
+		      size_t size);
+int ipts_control_send_feedback(struct ipts_context *ipts, u32 buffer);
+int ipts_control_set_feature(struct ipts_context *ipts, u8 report, u8 value);
+int ipts_control_start(struct ipts_context *ipts);
+int ipts_control_restart(struct ipts_context *ipts);
+int ipts_control_stop(struct ipts_context *ipts);
+
+#endif /* _IPTS_CONTROL_H_ */
diff --git a/drivers/misc/ipts/mei.c b/drivers/misc/ipts/mei.c
new file mode 100644
index 000000000000..59ecf13e00d2
--- /dev/null
+++ b/drivers/misc/ipts/mei.c
@@ -0,0 +1,125 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Copyright (c) 2016 Intel Corporation
+ * Copyright (c) 2020 Dorian Stoll
+ *
+ * Linux driver for Intel Precise Touch & Stylus
+ */
+
+#include <linux/delay.h>
+#include <linux/dma-mapping.h>
+#include <linux/mei_cl_bus.h>
+#include <linux/mod_devicetable.h>
+#include <linux/module.h>
+#include <linux/slab.h>
+
+#include "context.h"
+#include "control.h"
+#include "protocol.h"
+#include "receiver.h"
+#include "uapi.h"
+
+static int ipts_mei_set_dma_mask(struct mei_cl_device *cldev)
+{
+	int ret;
+
+	ret = dma_coerce_mask_and_coherent(&cldev->dev, DMA_BIT_MASK(64));
+	if (!ret)
+		return 0;
+
+	return dma_coerce_mask_and_coherent(&cldev->dev, DMA_BIT_MASK(32));
+}
+
+static int ipts_mei_probe(struct mei_cl_device *cldev,
+			  const struct mei_cl_device_id *id)
+{
+	int ret;
+	struct ipts_context *ipts;
+
+	if (ipts_mei_set_dma_mask(cldev)) {
+		dev_err(&cldev->dev, "Failed to set DMA mask for IPTS\n");
+		return -EFAULT;
+	}
+
+	ret = mei_cldev_enable(cldev);
+	if (ret) {
+		dev_err(&cldev->dev, "Failed to enable MEI device: %d\n", ret);
+		return ret;
+	}
+
+	ipts = kzalloc(sizeof(*ipts), GFP_KERNEL);
+	if (!ipts) {
+		mei_cldev_disable(cldev);
+		return -ENOMEM;
+	}
+
+	ipts->cldev = cldev;
+	ipts->dev = &cldev->dev;
+	ipts->status = IPTS_HOST_STATUS_STOPPED;
+
+	mei_cldev_set_drvdata(cldev, ipts);
+	mei_cldev_register_rx_cb(cldev, ipts_receiver_callback);
+
+	return ipts_control_start(ipts);
+}
+
+static void ipts_mei_remove(struct mei_cl_device *cldev)
+{
+	int i;
+	struct ipts_context *ipts = mei_cldev_get_drvdata(cldev);
+
+	ipts_control_stop(ipts);
+
+	for (i = 0; i < 20; i++) {
+		if (ipts->status == IPTS_HOST_STATUS_STOPPED)
+			break;
+
+		msleep(25);
+	}
+
+	mei_cldev_disable(cldev);
+	kfree(ipts);
+}
+
+static struct mei_cl_device_id ipts_mei_device_id_table[] = {
+	{ "", IPTS_MEI_UUID, MEI_CL_VERSION_ANY },
+	{},
+};
+MODULE_DEVICE_TABLE(mei, ipts_mei_device_id_table);
+
+static struct mei_cl_driver ipts_mei_driver = {
+	.id_table = ipts_mei_device_id_table,
+	.name = "ipts",
+	.probe = ipts_mei_probe,
+	.remove = ipts_mei_remove,
+};
+
+static int __init ipts_mei_init(void)
+{
+	int ret;
+
+	ret = ipts_uapi_init();
+	if (ret)
+		return ret;
+
+	ret = mei_cldev_driver_register(&ipts_mei_driver);
+	if (ret) {
+		ipts_uapi_free();
+		return ret;
+	}
+
+	return 0;
+}
+
+static void __exit ipts_mei_exit(void)
+{
+	mei_cldev_driver_unregister(&ipts_mei_driver);
+	ipts_uapi_free();
+}
+
+MODULE_DESCRIPTION("IPTS touchscreen driver");
+MODULE_AUTHOR("Dorian Stoll <dorian.stoll@tmsp.io>");
+MODULE_LICENSE("GPL");
+
+module_init(ipts_mei_init);
+module_exit(ipts_mei_exit);
diff --git a/drivers/misc/ipts/protocol.h b/drivers/misc/ipts/protocol.h
new file mode 100644
index 000000000000..c3458904a94d
--- /dev/null
+++ b/drivers/misc/ipts/protocol.h
@@ -0,0 +1,347 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/*
+ * Copyright (c) 2016 Intel Corporation
+ * Copyright (c) 2020 Dorian Stoll
+ *
+ * Linux driver for Intel Precise Touch & Stylus
+ */
+
+#ifndef _IPTS_PROTOCOL_H_
+#define _IPTS_PROTOCOL_H_
+
+#include <linux/types.h>
+
+/*
+ * The MEI client ID for IPTS functionality.
+ */
+#define IPTS_MEI_UUID                                                          \
+	UUID_LE(0x3e8d0870, 0x271a, 0x4208, 0x8e, 0xb5, 0x9a, 0xcb, 0x94,      \
+		0x02, 0xae, 0x04)
+
+/*
+ * Queries the device for vendor specific information.
+ *
+ * The command must not contain any payload.
+ * The response will contain struct ipts_get_device_info_rsp as payload.
+ */
+#define IPTS_CMD_GET_DEVICE_INFO 0x00000001
+#define IPTS_RSP_GET_DEVICE_INFO 0x80000001
+
+/*
+ * Sets the mode that IPTS will operate in.
+ *
+ * The command must contain struct ipts_set_mode_cmd as payload.
+ * The response will not contain any payload.
+ */
+#define IPTS_CMD_SET_MODE 0x00000002
+#define IPTS_RSP_SET_MODE 0x80000002
+
+/*
+ * Configures the memory buffers that the ME will use
+ * for passing data to the host.
+ *
+ * The command must contain struct ipts_set_mem_window_cmd as payload.
+ * The response will not contain any payload.
+ */
+#define IPTS_CMD_SET_MEM_WINDOW 0x00000003
+#define IPTS_RSP_SET_MEM_WINDOW 0x80000003
+
+/*
+ * Signals that the host is ready to receive data to the ME.
+ *
+ * The command must not contain any payload.
+ * The response will not contain any payload.
+ */
+#define IPTS_CMD_READY_FOR_DATA 0x00000005
+#define IPTS_RSP_READY_FOR_DATA 0x80000005
+
+/*
+ * Signals that a buffer can be refilled to the ME.
+ *
+ * The command must contain struct ipts_feedback_cmd as payload.
+ * The response will not contain any payload.
+ */
+#define IPTS_CMD_FEEDBACK 0x00000006
+#define IPTS_RSP_FEEDBACK 0x80000006
+
+/*
+ * Resets the data flow from the ME to the hosts and
+ * clears the buffers that were set with SET_MEM_WINDOW.
+ *
+ * The command must not contain any payload.
+ * The response will not contain any payload.
+ */
+#define IPTS_CMD_CLEAR_MEM_WINDOW 0x00000007
+#define IPTS_RSP_CLEAR_MEM_WINDOW 0x80000007
+
+/*
+ * Instructs the ME to reset the touch sensor.
+ *
+ * The command must contain struct ipts_reset_sensor_cmd as payload.
+ * The response will not contain any payload.
+ */
+#define IPTS_CMD_RESET_SENSOR 0x0000000B
+#define IPTS_RSP_RESET_SENSOR 0x8000000B
+
+/**
+ * enum ipts_status - Possible status codes returned by IPTS commands.
+ * @IPTS_STATUS_SUCCESS:                 Operation completed successfully.
+ * @IPTS_STATUS_INVALID_PARAMS:          Command contained a payload with invalid parameters.
+ * @IPTS_STATUS_ACCESS_DENIED:           ME could not validate buffer addresses supplied by host.
+ * @IPTS_STATUS_CMD_SIZE_ERROR:          Command contains an invalid payload.
+ * @IPTS_STATUS_NOT_READY:               Buffer addresses have not been set.
+ * @IPTS_STATUS_REQUEST_OUTSTANDING:     There is an outstanding command of the same type.
+ *                                       The host must wait for a response before sending another
+ *                                       command of the same type.
+ * @IPTS_STATUS_NO_SENSOR_FOUND:         No sensor could be found. Either no sensor is connected, it
+ *                                       has not been initialized yet, or the system is improperly
+ *                                       configured.
+ * @IPTS_STATUS_OUT_OF_MEMORY:           Not enough free memory for requested operation.
+ * @IPTS_STATUS_INTERNAL_ERROR:          An unexpected error occurred.
+ * @IPTS_STATUS_SENSOR_DISABLED:         The sensor has been disabled and must be reinitialized.
+ * @IPTS_STATUS_COMPAT_CHECK_FAIL:       Compatibility revision check between sensor and ME failed.
+ *                                       The host can ignore this error and attempt to continue.
+ * @IPTS_STATUS_SENSOR_EXPECTED_RESET:   The sensor went through a reset initiated by ME or host.
+ * @IPTS_STATUS_SENSOR_UNEXPECTED_RESET: The sensor went through an unexpected reset.
+ * @IPTS_STATUS_RESET_FAILED:            Requested sensor reset failed to complete.
+ * @IPTS_STATUS_TIMEOUT:                 The operation timed out.
+ * @IPTS_STATUS_TEST_MODE_FAIL:          Test mode pattern did not match expected values.
+ * @IPTS_STATUS_SENSOR_FAIL_FATAL:       The sensor reported a fatal error during reset sequence.
+ *                                       Further progress is not possible.
+ * @IPTS_STATUS_SENSOR_FAIL_NONFATAL:    The sensor reported a fatal error during reset sequence.
+ *                                       The host can attempt to continue.
+ * @IPTS_STATUS_INVALID_DEVICE_CAPS:     The device reported invalid capabilities.
+ * @IPTS_STATUS_QUIESCE_IO_IN_PROGRESS:  Command cannot be completed until Quiesce IO is done.
+ */
+enum ipts_status {
+	IPTS_STATUS_SUCCESS = 0,
+	IPTS_STATUS_INVALID_PARAMS = 1,
+	IPTS_STATUS_ACCESS_DENIED = 2,
+	IPTS_STATUS_CMD_SIZE_ERROR = 3,
+	IPTS_STATUS_NOT_READY = 4,
+	IPTS_STATUS_REQUEST_OUTSTANDING = 5,
+	IPTS_STATUS_NO_SENSOR_FOUND = 6,
+	IPTS_STATUS_OUT_OF_MEMORY = 7,
+	IPTS_STATUS_INTERNAL_ERROR = 8,
+	IPTS_STATUS_SENSOR_DISABLED = 9,
+	IPTS_STATUS_COMPAT_CHECK_FAIL = 10,
+	IPTS_STATUS_SENSOR_EXPECTED_RESET = 11,
+	IPTS_STATUS_SENSOR_UNEXPECTED_RESET = 12,
+	IPTS_STATUS_RESET_FAILED = 13,
+	IPTS_STATUS_TIMEOUT = 14,
+	IPTS_STATUS_TEST_MODE_FAIL = 15,
+	IPTS_STATUS_SENSOR_FAIL_FATAL = 16,
+	IPTS_STATUS_SENSOR_FAIL_NONFATAL = 17,
+	IPTS_STATUS_INVALID_DEVICE_CAPS = 18,
+	IPTS_STATUS_QUIESCE_IO_IN_PROGRESS = 19,
+};
+
+/*
+ * The amount of buffers that is used for IPTS
+ */
+#define IPTS_BUFFERS 16
+
+/*
+ * The special buffer ID that is used for direct host2me feedback.
+ */
+#define IPTS_HOST2ME_BUFFER IPTS_BUFFERS
+
+/**
+ * enum ipts_mode - Operation mode for IPTS hardware
+ * @IPTS_MODE_SINGLETOUCH: Fallback that supports only one finger and no stylus.
+ *                         The data is received as a HID report with ID 64.
+ * @IPTS_MODE_MULTITOUCH:  The "proper" operation mode for IPTS. It will return
+ *                         stylus data as well as capacitive heatmap touch data.
+ *                         This data needs to be processed in userspace.
+ */
+enum ipts_mode {
+	IPTS_MODE_SINGLETOUCH = 0,
+	IPTS_MODE_MULTITOUCH = 1,
+};
+
+/**
+ * struct ipts_set_mode_cmd - Payload for the SET_MODE command.
+ * @mode: The mode that IPTS should operate in.
+ */
+struct ipts_set_mode_cmd {
+	enum ipts_mode mode;
+	u8 reserved[12];
+} __packed;
+
+#define IPTS_WORKQUEUE_SIZE	 8192
+#define IPTS_WORKQUEUE_ITEM_SIZE 16
+
+/**
+ * struct ipts_set_mem_window_cmd - Payload for the SET_MEM_WINDOW command.
+ * @data_buffer_addr_lower:     Lower 32 bits of the data buffer addresses.
+ * @data_buffer_addr_upper:     Upper 32 bits of the data buffer addresses.
+ * @workqueue_addr_lower:       Lower 32 bits of the workqueue buffer address.
+ * @workqueue_addr_upper:       Upper 32 bits of the workqueue buffer address.
+ * @doorbell_addr_lower:        Lower 32 bits of the doorbell buffer address.
+ * @doorbell_addr_upper:        Upper 32 bits of the doorbell buffer address.
+ * @feedback_buffer_addr_lower: Lower 32 bits of the feedback buffer addresses.
+ * @feedback_buffer_addr_upper: Upper 32 bits of the feedback buffer addresses.
+ * @host2me_addr_lower:         Lower 32 bits of the host2me buffer address.
+ * @host2me_addr_upper:         Upper 32 bits of the host2me buffer address.
+ * @workqueue_item_size:        Magic value. (IPTS_WORKQUEUE_ITEM_SIZE)
+ * @workqueue_size:             Magic value. (IPTS_WORKQUEUE_SIZE)
+ *
+ * The data buffers are buffers that get filled with touch data by the ME.
+ * The doorbell buffer is a u32 that gets incremented by the ME once a data
+ * buffer has been filled with new data.
+ *
+ * The other buffers are required for using GuC submission with binary
+ * firmware. Since support for GuC submission has been dropped from i915,
+ * they are not used anymore, but they need to be allocated and passed,
+ * otherwise the hardware will refuse to start.
+ */
+struct ipts_set_mem_window_cmd {
+	u32 data_buffer_addr_lower[IPTS_BUFFERS];
+	u32 data_buffer_addr_upper[IPTS_BUFFERS];
+	u32 workqueue_addr_lower;
+	u32 workqueue_addr_upper;
+	u32 doorbell_addr_lower;
+	u32 doorbell_addr_upper;
+	u32 feedback_buffer_addr_lower[IPTS_BUFFERS];
+	u32 feedback_buffer_addr_upper[IPTS_BUFFERS];
+	u32 host2me_addr_lower;
+	u32 host2me_addr_upper;
+	u32 host2me_size;
+	u8 reserved1;
+	u8 workqueue_item_size;
+	u16 workqueue_size;
+	u8 reserved[32];
+} __packed;
+
+/**
+ * struct ipts_feedback_cmd - Payload for the FEEDBACK command.
+ * @buffer: The buffer that the ME should refill.
+ */
+struct ipts_feedback_cmd {
+	u32 buffer;
+	u8 reserved[12];
+} __packed;
+
+/**
+ * enum ipts_feedback_cmd_type - Commands that can be executed on the sensor through feedback.
+ */
+enum ipts_feedback_cmd_type {
+	IPTS_FEEDBACK_CMD_TYPE_NONE = 0,
+	IPTS_FEEDBACK_CMD_TYPE_SOFT_RESET = 1,
+	IPTS_FEEDBACK_CMD_TYPE_GOTO_ARMED = 2,
+	IPTS_FEEDBACK_CMD_TYPE_GOTO_SENSING = 3,
+	IPTS_FEEDBACK_CMD_TYPE_GOTO_SLEEP = 4,
+	IPTS_FEEDBACK_CMD_TYPE_GOTO_DOZE = 5,
+	IPTS_FEEDBACK_CMD_TYPE_HARD_RESET = 6,
+};
+
+/**
+ * enum ipts_feedback_data_type - Describes the data that a feedback buffer contains.
+ * @IPTS_FEEDBACK_DATA_TYPE_VENDOR:        The buffer contains vendor specific feedback.
+ * @IPTS_FEEDBACK_DATA_TYPE_SET_FEATURES:  The buffer contains a HID set features command.
+ * @IPTS_FEEDBACK_DATA_TYPE_GET_FEATURES:  The buffer contains a HID get features command.
+ * @IPTS_FEEDBACK_DATA_TYPE_OUTPUT_REPORT: The buffer contains a HID output report.
+ * @IPTS_FEEDBACK_DATA_TYPE_STORE_DATA:    The buffer contains calibration data for the sensor.
+ */
+enum ipts_feedback_data_type {
+	IPTS_FEEDBACK_DATA_TYPE_VENDOR = 0,
+	IPTS_FEEDBACK_DATA_TYPE_SET_FEATURES = 1,
+	IPTS_FEEDBACK_DATA_TYPE_GET_FEATURES = 2,
+	IPTS_FEEDBACK_DATA_TYPE_OUTPUT_REPORT = 3,
+	IPTS_FEEDBACK_DATA_TYPE_STORE_DATA = 4,
+};
+
+/**
+ * struct ipts_feedback_buffer - The contents of an IPTS feedback buffer.
+ * @cmd_type: A command that should be executed on the sensor.
+ * @size: The size of the payload to be written.
+ * @buffer: The ID of the buffer that contains this feedback data.
+ * @protocol: The protocol version of the EDS.
+ * @data_type: The type of payload that the buffer contains.
+ * @spi_offset: The offset at which to write the payload data.
+ * @payload: Payload for the feedback command, or 0 if no payload is sent.
+ */
+struct ipts_feedback_buffer {
+	enum ipts_feedback_cmd_type cmd_type;
+	u32 size;
+	u32 buffer;
+	u32 protocol;
+	enum ipts_feedback_data_type data_type;
+	u32 spi_offset;
+	u8 reserved[40];
+	u8 payload[];
+} __packed;
+
+/**
+ * enum ipts_reset_type - Possible ways of resetting the touch sensor
+ * @IPTS_RESET_TYPE_HARD: Perform hardware reset using GPIO pin.
+ * @IPTS_RESET_TYPE_SOFT: Perform software reset using SPI interface.
+ */
+enum ipts_reset_type {
+	IPTS_RESET_TYPE_HARD = 0,
+	IPTS_RESET_TYPE_SOFT = 1,
+};
+
+/**
+ * struct ipts_reset_sensor_cmd - Payload for the RESET_SENSOR command.
+ * @type: What type of reset should be performed.
+ */
+struct ipts_reset_sensor_cmd {
+	enum ipts_reset_type type;
+	u8 reserved[4];
+} __packed;
+
+/**
+ * struct ipts_command - A message sent from the host to the ME.
+ * @code:    The message code describing the command. (see IPTS_CMD_*)
+ * @payload: Payload for the command, or 0 if no payload is required.
+ */
+struct ipts_command {
+	u32 code;
+	u8 payload[320];
+} __packed;
+
+/**
+ * struct ipts_device_info - Payload for the GET_DEVICE_INFO response.
+ * @vendor_id:     Vendor ID of the touch sensor.
+ * @device_id:     Device ID of the touch sensor.
+ * @hw_rev:        Hardware revision of the touch sensor.
+ * @fw_rev:        Firmware revision of the touch sensor.
+ * @data_size:     Required size of one data buffer.
+ * @feedback_size: Required size of one feedback buffer.
+ * @mode:          Current operation mode of IPTS.
+ * @max_contacts:  The amount of concurrent touches supported by the sensor.
+ */
+struct ipts_get_device_info_rsp {
+	u16 vendor_id;
+	u16 device_id;
+	u32 hw_rev;
+	u32 fw_rev;
+	u32 data_size;
+	u32 feedback_size;
+	enum ipts_mode mode;
+	u8 max_contacts;
+	u8 reserved[19];
+} __packed;
+
+/**
+ * struct ipts_feedback_rsp - Payload for the FEEDBACK response.
+ * @buffer: The buffer that has received feedback.
+ */
+struct ipts_feedback_rsp {
+	u32 buffer;
+} __packed;
+
+/**
+ * struct ipts_response - A message sent from the ME to the host.
+ * @code:    The message code describing the response. (see IPTS_RSP_*)
+ * @status:  The status code returned by the command.
+ * @payload: Payload returned by the command.
+ */
+struct ipts_response {
+	u32 code;
+	enum ipts_status status;
+	u8 payload[80];
+} __packed;
+
+#endif /* _IPTS_PROTOCOL_H_ */
diff --git a/drivers/misc/ipts/receiver.c b/drivers/misc/ipts/receiver.c
new file mode 100644
index 000000000000..23dca13c2139
--- /dev/null
+++ b/drivers/misc/ipts/receiver.c
@@ -0,0 +1,224 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Copyright (c) 2016 Intel Corporation
+ * Copyright (c) 2020 Dorian Stoll
+ *
+ * Linux driver for Intel Precise Touch & Stylus
+ */
+
+#include <linux/mei_cl_bus.h>
+#include <linux/moduleparam.h>
+#include <linux/types.h>
+
+#include "context.h"
+#include "control.h"
+#include "protocol.h"
+#include "resources.h"
+
+/*
+ * Temporary parameter to guard gen7 multitouch mode.
+ * Remove once gen7 has stable iptsd support.
+ */
+static bool gen7mt;
+module_param(gen7mt, bool, 0644);
+
+static int ipts_receiver_handle_get_device_info(struct ipts_context *ipts,
+						struct ipts_response *rsp)
+{
+	struct ipts_set_mode_cmd cmd;
+
+	memcpy(&ipts->device_info, rsp->payload,
+	       sizeof(struct ipts_get_device_info_rsp));
+
+	memset(&cmd, 0, sizeof(struct ipts_set_mode_cmd));
+	cmd.mode = IPTS_MODE_MULTITOUCH;
+
+	return ipts_control_send(ipts, IPTS_CMD_SET_MODE, &cmd,
+				 sizeof(struct ipts_set_mode_cmd));
+}
+
+static int ipts_receiver_handle_set_mode(struct ipts_context *ipts)
+{
+	int i, ret;
+	struct ipts_set_mem_window_cmd cmd;
+
+	ret = ipts_resources_alloc(ipts);
+	if (ret) {
+		dev_err(ipts->dev, "Failed to allocate resources\n");
+		return ret;
+	}
+
+	memset(&cmd, 0, sizeof(struct ipts_set_mem_window_cmd));
+
+	for (i = 0; i < IPTS_BUFFERS; i++) {
+		cmd.data_buffer_addr_lower[i] =
+			lower_32_bits(ipts->data[i].dma_address);
+
+		cmd.data_buffer_addr_upper[i] =
+			upper_32_bits(ipts->data[i].dma_address);
+
+		cmd.feedback_buffer_addr_lower[i] =
+			lower_32_bits(ipts->feedback[i].dma_address);
+
+		cmd.feedback_buffer_addr_upper[i] =
+			upper_32_bits(ipts->feedback[i].dma_address);
+	}
+
+	cmd.workqueue_addr_lower = lower_32_bits(ipts->workqueue.dma_address);
+	cmd.workqueue_addr_upper = upper_32_bits(ipts->workqueue.dma_address);
+
+	cmd.doorbell_addr_lower = lower_32_bits(ipts->doorbell.dma_address);
+	cmd.doorbell_addr_upper = upper_32_bits(ipts->doorbell.dma_address);
+
+	cmd.host2me_addr_lower = lower_32_bits(ipts->host2me.dma_address);
+	cmd.host2me_addr_upper = upper_32_bits(ipts->host2me.dma_address);
+
+	cmd.workqueue_size = IPTS_WORKQUEUE_SIZE;
+	cmd.workqueue_item_size = IPTS_WORKQUEUE_ITEM_SIZE;
+
+	return ipts_control_send(ipts, IPTS_CMD_SET_MEM_WINDOW, &cmd,
+				 sizeof(struct ipts_set_mem_window_cmd));
+}
+
+static int ipts_receiver_handle_set_mem_window(struct ipts_context *ipts)
+{
+	int ret;
+
+	dev_info(ipts->dev, "Device %04hX:%04hX ready\n",
+		 ipts->device_info.vendor_id, ipts->device_info.device_id);
+	ipts->status = IPTS_HOST_STATUS_STARTED;
+
+	ret = ipts_control_send(ipts, IPTS_CMD_READY_FOR_DATA, NULL, 0);
+	if (ret)
+		return ret;
+
+	if (!gen7mt)
+		return 0;
+
+	return ipts_control_set_feature(ipts, 0x5, 0x1);
+}
+
+static int ipts_receiver_handle_feedback(struct ipts_context *ipts,
+					 struct ipts_response *rsp)
+{
+	struct ipts_feedback_rsp feedback;
+
+	if (ipts->status != IPTS_HOST_STATUS_STOPPING)
+		return 0;
+
+	memcpy(&feedback, rsp->payload, sizeof(feedback));
+
+	if (feedback.buffer < IPTS_BUFFERS - 1)
+		return ipts_control_send_feedback(ipts, feedback.buffer + 1);
+
+	return ipts_control_send(ipts, IPTS_CMD_CLEAR_MEM_WINDOW, NULL, 0);
+}
+
+static int ipts_receiver_handle_clear_mem_window(struct ipts_context *ipts)
+{
+	ipts->status = IPTS_HOST_STATUS_STOPPED;
+
+	if (ipts->restart)
+		return ipts_control_start(ipts);
+
+	return 0;
+}
+
+static bool ipts_receiver_sensor_was_reset(u32 status)
+{
+	return status == IPTS_STATUS_SENSOR_EXPECTED_RESET ||
+	       status == IPTS_STATUS_SENSOR_UNEXPECTED_RESET;
+}
+
+static bool ipts_receiver_handle_error(struct ipts_context *ipts,
+				       struct ipts_response *rsp)
+{
+	bool error;
+
+	switch (rsp->status) {
+	case IPTS_STATUS_SUCCESS:
+	case IPTS_STATUS_COMPAT_CHECK_FAIL:
+		error = false;
+		break;
+	case IPTS_STATUS_INVALID_PARAMS:
+		error = rsp->code != IPTS_RSP_FEEDBACK;
+		break;
+	case IPTS_STATUS_SENSOR_DISABLED:
+		error = ipts->status != IPTS_HOST_STATUS_STOPPING;
+		break;
+	default:
+		error = true;
+		break;
+	}
+
+	if (!error)
+		return false;
+
+	dev_err(ipts->dev, "Command 0x%08x failed: %d\n", rsp->code,
+		rsp->status);
+
+	if (ipts_receiver_sensor_was_reset(rsp->status)) {
+		dev_err(ipts->dev, "Sensor was reset\n");
+
+		if (ipts_control_restart(ipts))
+			dev_err(ipts->dev, "Failed to restart IPTS\n");
+	}
+
+	return true;
+}
+
+static void ipts_receiver_handle_response(struct ipts_context *ipts,
+					  struct ipts_response *rsp)
+{
+	int ret;
+
+	if (ipts_receiver_handle_error(ipts, rsp))
+		return;
+
+	switch (rsp->code) {
+	case IPTS_RSP_GET_DEVICE_INFO:
+		ret = ipts_receiver_handle_get_device_info(ipts, rsp);
+		break;
+	case IPTS_RSP_SET_MODE:
+		ret = ipts_receiver_handle_set_mode(ipts);
+		break;
+	case IPTS_RSP_SET_MEM_WINDOW:
+		ret = ipts_receiver_handle_set_mem_window(ipts);
+		break;
+	case IPTS_RSP_FEEDBACK:
+		ret = ipts_receiver_handle_feedback(ipts, rsp);
+		break;
+	case IPTS_RSP_CLEAR_MEM_WINDOW:
+		ret = ipts_receiver_handle_clear_mem_window(ipts);
+		break;
+	default:
+		ret = 0;
+		break;
+	}
+
+	if (!ret)
+		return;
+
+	dev_err(ipts->dev, "Error while handling response 0x%08x: %d\n",
+		rsp->code, ret);
+
+	if (ipts_control_stop(ipts))
+		dev_err(ipts->dev, "Failed to stop IPTS\n");
+}
+
+void ipts_receiver_callback(struct mei_cl_device *cldev)
+{
+	int ret;
+	struct ipts_response rsp;
+	struct ipts_context *ipts;
+
+	ipts = mei_cldev_get_drvdata(cldev);
+
+	ret = mei_cldev_recv(cldev, (u8 *)&rsp, sizeof(struct ipts_response));
+	if (ret <= 0) {
+		dev_err(ipts->dev, "Error while reading response: %d\n", ret);
+		return;
+	}
+
+	ipts_receiver_handle_response(ipts, &rsp);
+}
diff --git a/drivers/misc/ipts/receiver.h b/drivers/misc/ipts/receiver.h
new file mode 100644
index 000000000000..7f075afa7ef8
--- /dev/null
+++ b/drivers/misc/ipts/receiver.h
@@ -0,0 +1,16 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/*
+ * Copyright (c) 2016 Intel Corporation
+ * Copyright (c) 2020 Dorian Stoll
+ *
+ * Linux driver for Intel Precise Touch & Stylus
+ */
+
+#ifndef _IPTS_RECEIVER_H_
+#define _IPTS_RECEIVER_H_
+
+#include <linux/mei_cl_bus.h>
+
+void ipts_receiver_callback(struct mei_cl_device *cldev);
+
+#endif /* _IPTS_RECEIVER_H_ */
diff --git a/drivers/misc/ipts/resources.c b/drivers/misc/ipts/resources.c
new file mode 100644
index 000000000000..8e3a2409e438
--- /dev/null
+++ b/drivers/misc/ipts/resources.c
@@ -0,0 +1,128 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Copyright (c) 2016 Intel Corporation
+ * Copyright (c) 2020 Dorian Stoll
+ *
+ * Linux driver for Intel Precise Touch & Stylus
+ */
+
+#include <linux/dma-mapping.h>
+
+#include "context.h"
+
+void ipts_resources_free(struct ipts_context *ipts)
+{
+	int i;
+	struct ipts_buffer_info *buffers;
+
+	u32 data_buffer_size = ipts->device_info.data_size;
+	u32 feedback_buffer_size = ipts->device_info.feedback_size;
+
+	buffers = ipts->data;
+	for (i = 0; i < IPTS_BUFFERS; i++) {
+		if (!buffers[i].address)
+			continue;
+
+		dma_free_coherent(ipts->dev, data_buffer_size,
+				  buffers[i].address, buffers[i].dma_address);
+
+		buffers[i].address = NULL;
+		buffers[i].dma_address = 0;
+	}
+
+	buffers = ipts->feedback;
+	for (i = 0; i < IPTS_BUFFERS; i++) {
+		if (!buffers[i].address)
+			continue;
+
+		dma_free_coherent(ipts->dev, feedback_buffer_size,
+				  buffers[i].address, buffers[i].dma_address);
+
+		buffers[i].address = NULL;
+		buffers[i].dma_address = 0;
+	}
+
+	if (ipts->doorbell.address) {
+		dma_free_coherent(ipts->dev, sizeof(u32),
+				  ipts->doorbell.address,
+				  ipts->doorbell.dma_address);
+
+		ipts->doorbell.address = NULL;
+		ipts->doorbell.dma_address = 0;
+	}
+
+	if (ipts->workqueue.address) {
+		dma_free_coherent(ipts->dev, sizeof(u32),
+				  ipts->workqueue.address,
+				  ipts->workqueue.dma_address);
+
+		ipts->workqueue.address = NULL;
+		ipts->workqueue.dma_address = 0;
+	}
+
+	if (ipts->host2me.address) {
+		dma_free_coherent(ipts->dev, feedback_buffer_size,
+				  ipts->host2me.address,
+				  ipts->host2me.dma_address);
+
+		ipts->host2me.address = NULL;
+		ipts->host2me.dma_address = 0;
+	}
+}
+
+int ipts_resources_alloc(struct ipts_context *ipts)
+{
+	int i;
+	struct ipts_buffer_info *buffers;
+
+	u32 data_buffer_size = ipts->device_info.data_size;
+	u32 feedback_buffer_size = ipts->device_info.feedback_size;
+
+	buffers = ipts->data;
+	for (i = 0; i < IPTS_BUFFERS; i++) {
+		buffers[i].address =
+			dma_alloc_coherent(ipts->dev, data_buffer_size,
+					   &buffers[i].dma_address, GFP_KERNEL);
+
+		if (!buffers[i].address)
+			goto release_resources;
+	}
+
+	buffers = ipts->feedback;
+	for (i = 0; i < IPTS_BUFFERS; i++) {
+		buffers[i].address =
+			dma_alloc_coherent(ipts->dev, feedback_buffer_size,
+					   &buffers[i].dma_address, GFP_KERNEL);
+
+		if (!buffers[i].address)
+			goto release_resources;
+	}
+
+	ipts->doorbell.address =
+		dma_alloc_coherent(ipts->dev, sizeof(u32),
+				   &ipts->doorbell.dma_address, GFP_KERNEL);
+
+	if (!ipts->doorbell.address)
+		goto release_resources;
+
+	ipts->workqueue.address =
+		dma_alloc_coherent(ipts->dev, sizeof(u32),
+				   &ipts->workqueue.dma_address, GFP_KERNEL);
+
+	if (!ipts->workqueue.address)
+		goto release_resources;
+
+	ipts->host2me.address =
+		dma_alloc_coherent(ipts->dev, feedback_buffer_size,
+				   &ipts->host2me.dma_address, GFP_KERNEL);
+
+	if (!ipts->workqueue.address)
+		goto release_resources;
+
+	return 0;
+
+release_resources:
+
+	ipts_resources_free(ipts);
+	return -ENOMEM;
+}
diff --git a/drivers/misc/ipts/resources.h b/drivers/misc/ipts/resources.h
new file mode 100644
index 000000000000..fdac0eee9156
--- /dev/null
+++ b/drivers/misc/ipts/resources.h
@@ -0,0 +1,17 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/*
+ * Copyright (c) 2016 Intel Corporation
+ * Copyright (c) 2020 Dorian Stoll
+ *
+ * Linux driver for Intel Precise Touch & Stylus
+ */
+
+#ifndef _IPTS_RESOURCES_H_
+#define _IPTS_RESOURCES_H_
+
+#include "context.h"
+
+int ipts_resources_alloc(struct ipts_context *ipts);
+void ipts_resources_free(struct ipts_context *ipts);
+
+#endif /* _IPTS_RESOURCES_H_ */
diff --git a/drivers/misc/ipts/uapi.c b/drivers/misc/ipts/uapi.c
new file mode 100644
index 000000000000..598f0710ad64
--- /dev/null
+++ b/drivers/misc/ipts/uapi.c
@@ -0,0 +1,208 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Copyright (c) 2016 Intel Corporation
+ * Copyright (c) 2020 Dorian Stoll
+ *
+ * Linux driver for Intel Precise Touch & Stylus
+ */
+
+#include <linux/cdev.h>
+#include <linux/delay.h>
+#include <linux/device.h>
+#include <linux/fs.h>
+#include <linux/types.h>
+#include <linux/uaccess.h>
+
+#include "context.h"
+#include "control.h"
+#include "protocol.h"
+#include "uapi.h"
+
+struct ipts_uapi uapi;
+
+static ssize_t ipts_uapi_read(struct file *file, char __user *buf, size_t count,
+			      loff_t *offset)
+{
+	int buffer;
+	int maxbytes;
+	struct ipts_context *ipts = uapi.ipts;
+
+	buffer = MINOR(file->f_path.dentry->d_inode->i_rdev);
+
+	if (!ipts || ipts->status != IPTS_HOST_STATUS_STARTED)
+		return -ENODEV;
+
+	maxbytes = ipts->device_info.data_size - *offset;
+	if (maxbytes <= 0 || count > maxbytes)
+		return -EINVAL;
+
+	if (copy_to_user(buf, ipts->data[buffer].address + *offset, count))
+		return -EFAULT;
+
+	return count;
+}
+
+static long ipts_uapi_ioctl_get_device_ready(struct ipts_context *ipts,
+					     unsigned long arg)
+{
+	void __user *buffer = (void __user *)arg;
+	u8 ready = 0;
+
+	if (ipts)
+		ready = ipts->status == IPTS_HOST_STATUS_STARTED;
+
+	if (copy_to_user(buffer, &ready, sizeof(u8)))
+		return -EFAULT;
+
+	return 0;
+}
+
+static long ipts_uapi_ioctl_get_device_info(struct ipts_context *ipts,
+					    unsigned long arg)
+{
+	struct ipts_device_info info;
+	void __user *buffer = (void __user *)arg;
+
+	if (!ipts || ipts->status != IPTS_HOST_STATUS_STARTED)
+		return -ENODEV;
+
+	info.vendor = ipts->device_info.vendor_id;
+	info.product = ipts->device_info.device_id;
+	info.version = ipts->device_info.fw_rev;
+	info.buffer_size = ipts->device_info.data_size;
+	info.max_contacts = ipts->device_info.max_contacts;
+
+	if (copy_to_user(buffer, &info, sizeof(struct ipts_device_info)))
+		return -EFAULT;
+
+	return 0;
+}
+
+static long ipts_uapi_ioctl_get_doorbell(struct ipts_context *ipts,
+					 unsigned long arg)
+{
+	void __user *buffer = (void __user *)arg;
+
+	if (!ipts || ipts->status != IPTS_HOST_STATUS_STARTED)
+		return -ENODEV;
+
+	if (copy_to_user(buffer, ipts->doorbell.address, sizeof(u32)))
+		return -EFAULT;
+
+	return 0;
+}
+
+static long ipts_uapi_ioctl_send_feedback(struct ipts_context *ipts,
+					  struct file *file)
+{
+	int ret;
+	u32 buffer;
+
+	if (!ipts || ipts->status != IPTS_HOST_STATUS_STARTED)
+		return -ENODEV;
+
+	buffer = MINOR(file->f_path.dentry->d_inode->i_rdev);
+
+	ret = ipts_control_send_feedback(ipts, buffer);
+	if (ret)
+		return -EFAULT;
+
+	return 0;
+}
+
+static long ipts_uapi_ioctl_send_reset(struct ipts_context *ipts)
+{
+	int ret;
+	struct ipts_reset_sensor_cmd cmd;
+
+	if (!ipts || ipts->status != IPTS_HOST_STATUS_STARTED)
+		return -ENODEV;
+
+	memset(&cmd, 0, sizeof(struct ipts_reset_sensor_cmd));
+	cmd.type = IPTS_RESET_TYPE_SOFT;
+
+	ret = ipts_control_send(ipts, IPTS_CMD_RESET_SENSOR, &cmd,
+				sizeof(struct ipts_reset_sensor_cmd));
+
+	if (ret)
+		return -EFAULT;
+
+	return 0;
+}
+
+static long ipts_uapi_ioctl(struct file *file, unsigned int cmd,
+			    unsigned long arg)
+{
+	struct ipts_context *ipts = uapi.ipts;
+
+	switch (cmd) {
+	case IPTS_IOCTL_GET_DEVICE_READY:
+		return ipts_uapi_ioctl_get_device_ready(ipts, arg);
+	case IPTS_IOCTL_GET_DEVICE_INFO:
+		return ipts_uapi_ioctl_get_device_info(ipts, arg);
+	case IPTS_IOCTL_GET_DOORBELL:
+		return ipts_uapi_ioctl_get_doorbell(ipts, arg);
+	case IPTS_IOCTL_SEND_FEEDBACK:
+		return ipts_uapi_ioctl_send_feedback(ipts, file);
+	case IPTS_IOCTL_SEND_RESET:
+		return ipts_uapi_ioctl_send_reset(ipts);
+	default:
+		return -ENOTTY;
+	}
+}
+
+static const struct file_operations ipts_uapi_fops = {
+	.owner = THIS_MODULE,
+	.read = ipts_uapi_read,
+	.unlocked_ioctl = ipts_uapi_ioctl,
+#ifdef CONFIG_COMPAT
+	.compat_ioctl = ipts_uapi_ioctl,
+#endif
+};
+
+void ipts_uapi_link(struct ipts_context *ipts)
+{
+	uapi.ipts = ipts;
+}
+
+void ipts_uapi_unlink(void)
+{
+	uapi.ipts = NULL;
+}
+
+int ipts_uapi_init(void)
+{
+	int i, major;
+
+	alloc_chrdev_region(&uapi.dev, 0, IPTS_BUFFERS, "ipts");
+	uapi.class = class_create(THIS_MODULE, "ipts");
+
+	major = MAJOR(uapi.dev);
+
+	cdev_init(&uapi.cdev, &ipts_uapi_fops);
+	uapi.cdev.owner = THIS_MODULE;
+	cdev_add(&uapi.cdev, MKDEV(major, 0), IPTS_BUFFERS);
+
+	for (i = 0; i < IPTS_BUFFERS; i++) {
+		device_create(uapi.class, NULL, MKDEV(major, i), NULL,
+			      "ipts/%d", i);
+	}
+
+	return 0;
+}
+
+void ipts_uapi_free(void)
+{
+	int i;
+	int major;
+
+	major = MAJOR(uapi.dev);
+
+	for (i = 0; i < IPTS_BUFFERS; i++)
+		device_destroy(uapi.class, MKDEV(major, i));
+
+	cdev_del(&uapi.cdev);
+
+	unregister_chrdev_region(MKDEV(major, 0), MINORMASK);
+	class_destroy(uapi.class);
+}
diff --git a/drivers/misc/ipts/uapi.h b/drivers/misc/ipts/uapi.h
new file mode 100644
index 000000000000..53fb86a88f97
--- /dev/null
+++ b/drivers/misc/ipts/uapi.h
@@ -0,0 +1,47 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/*
+ * Copyright (c) 2016 Intel Corporation
+ * Copyright (c) 2020 Dorian Stoll
+ *
+ * Linux driver for Intel Precise Touch & Stylus
+ */
+
+#ifndef _IPTS_UAPI_H_
+#define _IPTS_UAPI_H_
+
+#include <linux/types.h>
+
+#include "context.h"
+
+struct ipts_uapi {
+	dev_t dev;
+	struct class *class;
+	struct cdev cdev;
+
+	struct ipts_context *ipts;
+};
+
+struct ipts_device_info {
+	__u16 vendor;
+	__u16 product;
+	__u32 version;
+	__u32 buffer_size;
+	__u8 max_contacts;
+
+	/* For future expansion */
+	__u8 reserved[19];
+};
+
+#define IPTS_IOCTL_GET_DEVICE_READY _IOR(0x86, 0x01, __u8)
+#define IPTS_IOCTL_GET_DEVICE_INFO  _IOR(0x86, 0x02, struct ipts_device_info)
+#define IPTS_IOCTL_GET_DOORBELL	    _IOR(0x86, 0x03, __u32)
+#define IPTS_IOCTL_SEND_FEEDBACK    _IO(0x86, 0x04)
+#define IPTS_IOCTL_SEND_RESET	    _IO(0x86, 0x05)
+
+void ipts_uapi_link(struct ipts_context *ipts);
+void ipts_uapi_unlink(void);
+
+int ipts_uapi_init(void);
+void ipts_uapi_free(void);
+
+#endif /* _IPTS_UAPI_H_ */
-- 
2.38.1

From 07bec5cb1bc6283d4ee40cd258e81f6065bd0fc2 Mon Sep 17 00:00:00 2001
From: Liban Hannan <liban.p@gmail.com>
Date: Tue, 12 Apr 2022 23:31:12 +0100
Subject: [PATCH] iommu: ipts: use IOMMU passthrough mode for IPTS

Adds a quirk so that IOMMU uses passthrough mode for the IPTS device.
Otherwise, when IOMMU is enabled, IPTS produces DMAR errors like:

DMAR: [DMA Read NO_PASID] Request device [00:16.4] fault addr
0x104ea3000 [fault reason 0x06] PTE Read access is not set

This is very similar to the bug described at:
https://bugs.launchpad.net/bugs/1958004

Fixed with the following patch which this patch basically copies:
https://launchpadlibrarian.net/586396847/43255ca.diff
Patchset: ipts
---
 drivers/iommu/intel/iommu.c | 24 ++++++++++++++++++++++++
 1 file changed, 24 insertions(+)

diff --git a/drivers/iommu/intel/iommu.c b/drivers/iommu/intel/iommu.c
index ecc0b05b2796..4c895b5f7e2d 100644
--- a/drivers/iommu/intel/iommu.c
+++ b/drivers/iommu/intel/iommu.c
@@ -37,6 +37,8 @@
 #define IS_GFX_DEVICE(pdev) ((pdev->class >> 16) == PCI_BASE_CLASS_DISPLAY)
 #define IS_USB_DEVICE(pdev) ((pdev->class >> 8) == PCI_CLASS_SERIAL_USB)
 #define IS_ISA_DEVICE(pdev) ((pdev->class >> 8) == PCI_CLASS_BRIDGE_ISA)
+#define IS_IPTS(pdev) ((pdev)->vendor == PCI_VENDOR_ID_INTEL &&	\
+			    ((pdev)->device == 0x9d3e))
 #define IS_AZALIA(pdev) ((pdev)->vendor == 0x8086 && (pdev)->device == 0x3a3e)
 
 #define IOAPIC_RANGE_START	(0xfee00000)
@@ -281,12 +283,14 @@ int intel_iommu_enabled = 0;
 EXPORT_SYMBOL_GPL(intel_iommu_enabled);
 
 static int dmar_map_gfx = 1;
+static int dmar_map_ipts = 1;
 static int intel_iommu_superpage = 1;
 static int iommu_identity_mapping;
 static int iommu_skip_te_disable;
 
 #define IDENTMAP_GFX		2
 #define IDENTMAP_AZALIA		4
+#define IDENTMAP_IPTS		16
 
 const struct iommu_ops intel_iommu_ops;
 
@@ -2603,6 +2607,9 @@ static int device_def_domain_type(struct device *dev)
 
 		if ((iommu_identity_mapping & IDENTMAP_GFX) && IS_GFX_DEVICE(pdev))
 			return IOMMU_DOMAIN_IDENTITY;
+
+		if ((iommu_identity_mapping & IDENTMAP_IPTS) && IS_IPTS(pdev))
+			return IOMMU_DOMAIN_IDENTITY;
 	}
 
 	return 0;
@@ -2992,6 +2999,9 @@ static int __init init_dmars(void)
 	if (!dmar_map_gfx)
 		iommu_identity_mapping |= IDENTMAP_GFX;
 
+	if (!dmar_map_ipts)
+		iommu_identity_mapping |= IDENTMAP_IPTS;
+
 	check_tylersburg_isoch();
 
 	ret = si_domain_init(hw_pass_through);
@@ -4793,6 +4803,17 @@ static void quirk_iommu_igfx(struct pci_dev *dev)
 	dmar_map_gfx = 0;
 }
 
+static void quirk_iommu_ipts(struct pci_dev *dev)
+{
+	if (!IS_IPTS(dev))
+		return;
+
+	if (risky_device(dev))
+		return;
+
+	pci_info(dev, "Passthrough IOMMU for IPTS\n");
+	dmar_map_ipts = 0;
+}
 /* G4x/GM45 integrated gfx dmar support is totally busted. */
 DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_INTEL, 0x2a40, quirk_iommu_igfx);
 DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_INTEL, 0x2e00, quirk_iommu_igfx);
@@ -4828,6 +4849,9 @@ DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_INTEL, 0x1632, quirk_iommu_igfx);
 DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_INTEL, 0x163A, quirk_iommu_igfx);
 DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_INTEL, 0x163D, quirk_iommu_igfx);
 
+/* disable IPTS dmar support */
+DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_INTEL, 0x9D3E, quirk_iommu_ipts);
+
 static void quirk_iommu_rwbf(struct pci_dev *dev)
 {
 	if (risky_device(dev))
-- 
2.38.1