HID: intel_ish-hid: ISH Transport layer

The ISH transport layer (ishtp) is a bi-directional protocol implemented
on the top of PCI based inter processor communication layer. This layer
offers:
- Connection management
- Flow control with the firmware
- Multiple client sessions
- Client message transfer
- Client message reception
- DMA for RX and TX for fast data transfer

Refer to Documentation/hid/intel-ish-hid.txt for
overview of the functionality implemented in this layer.

Original-author: Daniel Drubin <daniel.drubin@intel.com>
Reviewed-and-tested-by: Ooi, Joyce <joyce.ooi@intel.com>
Tested-by: Grant Likely <grant.likely@secretlab.ca>
Tested-by: Rann Bar-On <rb6@duke.edu>
Tested-by: Atri Bhattacharya <badshah400@aim.com>
Signed-off-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>

drivers/hid/Kconfig

@@ -967,4 +967,6 @@ source "drivers/hid/usbhid/Kconfig"
 
 source "drivers/hid/i2c-hid/Kconfig"
 
+source "drivers/hid/intel-ish-hid/Kconfig"
+
 endmenu

drivers/hid/Makefile

@@ -113,3 +113,5 @@ obj-$(CONFIG_USB_MOUSE)		+= usbhid/
 obj-$(CONFIG_USB_KBD)		+= usbhid/
 
 obj-$(CONFIG_I2C_HID)		+= i2c-hid/
+
+obj-$(CONFIG_INTEL_ISH_HID)	+= intel-ish-hid/

drivers/hid/intel-ish-hid/Kconfig

+menu "Intel ISH HID support"
+	depends on X86_64 && PCI
+
+config INTEL_ISH_HID
+	tristate "Intel Integrated Sensor Hub"
+	default n
+	select HID
+	help
+	  The Integrated Sensor Hub (ISH) enables the ability to offload
+	  sensor polling and algorithm processing to a dedicated low power
+	  processor in the chipset. This allows the core processor to go into
+	  low power modes more often, resulting in the increased battery life.
+	  The current processors that support ISH are: Cherrytrail, Skylake,
+	  Broxton and Kaby Lake.
+
+	  Say Y here if you want to support Intel ISH. If unsure, say N.
+endmenu

drivers/hid/intel-ish-hid/Makefile

+#
+# Makefile - Intel ISH HID drivers
+# Copyright (c) 2014-2016, Intel Corporation.
+#
+#
+obj-$(CONFIG_INTEL_ISH_HID) += intel-ishtp.o
+intel-ishtp-objs := ishtp/init.o
+intel-ishtp-objs += ishtp/hbm.o
+intel-ishtp-objs += ishtp/client.o
+intel-ishtp-objs += ishtp/bus.o
+intel-ishtp-objs += ishtp/dma-if.o
+intel-ishtp-objs += ishtp/client-buffers.o

drivers/hid/intel-ish-hid/ishtp/bus.h

+/*
+ * ISHTP bus definitions
+ *
+ * Copyright (c) 2014-2016, Intel Corporation.
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
+ * more details.
+ */
+#ifndef _LINUX_ISHTP_CL_BUS_H
+#define _LINUX_ISHTP_CL_BUS_H
+
+#include <linux/device.h>
+#include <linux/mod_devicetable.h>
+
+struct ishtp_cl;
+struct ishtp_cl_device;
+struct ishtp_device;
+struct ishtp_msg_hdr;
+
+/**
+ * struct ishtp_cl_device - ISHTP device handle
+ * @dev:	device pointer
+ * @ishtp_dev:	pointer to ishtp device structure to primarily to access
+ *		hw device operation callbacks and properties
+ * @fw_client:	fw_client pointer to get fw information like protocol name
+ *		max message length etc.
+ * @device_link: Link to next client in the list on a bus
+ * @event_work:	Used to schedule rx event for client
+ * @driver_data: Storage driver private data
+ * @reference_count:	Used for get/put device
+ * @event_cb:	Callback to driver to send events
+ *
+ * An ishtp_cl_device pointer is returned from ishtp_add_device()
+ * and links ISHTP bus clients to their actual host client pointer.
+ * Drivers for ISHTP devices will get an ishtp_cl_device pointer
+ * when being probed and shall use it for doing bus I/O.
+ */
+struct ishtp_cl_device {
+	struct device		dev;
+	struct ishtp_device	*ishtp_dev;
+	struct ishtp_fw_client	*fw_client;
+	struct list_head	device_link;
+	struct work_struct	event_work;
+	void			*driver_data;
+	int			reference_count;
+	void (*event_cb)(struct ishtp_cl_device *device);
+};
+
+/**
+ * struct ishtp_cl_device - ISHTP device handle
+ * @driver:	driver instance on a bus
+ * @name:	Name of the device for probe
+ * @probe:	driver callback for device probe
+ * @remove:	driver callback on device removal
+ *
+ * Client drivers defines to get probed/removed for ISHTP client device.
+ */
+struct ishtp_cl_driver {
+	struct device_driver driver;
+	const char *name;
+	int (*probe)(struct ishtp_cl_device *dev);
+	int (*remove)(struct ishtp_cl_device *dev);
+	int (*reset)(struct ishtp_cl_device *dev);
+	const struct dev_pm_ops *pm;
+};
+
+
+int	ishtp_bus_new_client(struct ishtp_device *dev);
+void	ishtp_remove_all_clients(struct ishtp_device *dev);
+int	ishtp_cl_device_bind(struct ishtp_cl *cl);
+void	ishtp_cl_bus_rx_event(struct ishtp_cl_device *device);
+
+/* Write a multi-fragment message */
+int	ishtp_send_msg(struct ishtp_device *dev,
+		       struct ishtp_msg_hdr *hdr, void *msg,
+		       void (*ipc_send_compl)(void *),
+		       void *ipc_send_compl_prm);
+
+/* Write a single-fragment message */
+int	ishtp_write_message(struct ishtp_device *dev,
+			    struct ishtp_msg_hdr *hdr,
+			    unsigned char *buf);
+
+/* Use DMA to send/receive messages */
+int ishtp_use_dma_transfer(void);
+
+/* Exported functions */
+void	ishtp_bus_remove_all_clients(struct ishtp_device *ishtp_dev,
+				     bool warm_reset);
+
+void	ishtp_recv(struct ishtp_device *dev);
+void	ishtp_reset_handler(struct ishtp_device *dev);
+void	ishtp_reset_compl_handler(struct ishtp_device *dev);
+
+void	ishtp_put_device(struct ishtp_cl_device *);
+void	ishtp_get_device(struct ishtp_cl_device *);
+
+int	__ishtp_cl_driver_register(struct ishtp_cl_driver *driver,
+				   struct module *owner);
+#define ishtp_cl_driver_register(driver)		\
+	__ishtp_cl_driver_register(driver, THIS_MODULE)
+void	ishtp_cl_driver_unregister(struct ishtp_cl_driver *driver);
+
+int	ishtp_register_event_cb(struct ishtp_cl_device *device,
+				void (*read_cb)(struct ishtp_cl_device *));
+int	ishtp_fw_cl_by_uuid(struct ishtp_device *dev, const uuid_le *cuuid);
+
+#endif /* _LINUX_ISHTP_CL_BUS_H */

drivers/hid/intel-ish-hid/ishtp/client-buffers.c

+/*
+ * ISHTP Ring Buffers
+ *
+ * Copyright (c) 2003-2016, Intel Corporation.
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
+ * more details.
+ *
+ */
+
+#include <linux/slab.h>
+#include "client.h"
+
+/**
+ * ishtp_cl_alloc_rx_ring() - Allocate RX ring buffers
+ * @cl: client device instance
+ *
+ * Allocate and initialize RX ring buffers
+ *
+ * Return: 0 on success else -ENOMEM
+ */
+int ishtp_cl_alloc_rx_ring(struct ishtp_cl *cl)
+{
+	size_t	len = cl->device->fw_client->props.max_msg_length;
+	int	j;
+	struct ishtp_cl_rb *rb;
+	int	ret = 0;
+	unsigned long	flags;
+
+	for (j = 0; j < cl->rx_ring_size; ++j) {
+		rb = ishtp_io_rb_init(cl);
+		if (!rb) {
+			ret = -ENOMEM;
+			goto out;
+		}
+		ret = ishtp_io_rb_alloc_buf(rb, len);
+		if (ret)
+			goto out;
+		spin_lock_irqsave(&cl->free_list_spinlock, flags);
+		list_add_tail(&rb->list, &cl->free_rb_list.list);
+		spin_unlock_irqrestore(&cl->free_list_spinlock, flags);
+	}
+
+	return	0;
+
+out:
+	dev_err(&cl->device->dev, "error in allocating Rx buffers\n");
+	ishtp_cl_free_rx_ring(cl);
+	return	ret;
+}
+
+/**
+ * ishtp_cl_alloc_tx_ring() - Allocate TX ring buffers
+ * @cl: client device instance
+ *
+ * Allocate and initialize TX ring buffers
+ *
+ * Return: 0 on success else -ENOMEM
+ */
+int ishtp_cl_alloc_tx_ring(struct ishtp_cl *cl)
+{
+	size_t	len = cl->device->fw_client->props.max_msg_length;
+	int	j;
+	unsigned long	flags;
+
+	/* Allocate pool to free Tx bufs */
+	for (j = 0; j < cl->tx_ring_size; ++j) {
+		struct ishtp_cl_tx_ring	*tx_buf;
+
+		tx_buf = kmalloc(sizeof(struct ishtp_cl_tx_ring), GFP_KERNEL);
+		if (!tx_buf)
+			goto	out;
+
+		memset(tx_buf, 0, sizeof(struct ishtp_cl_tx_ring));
+		tx_buf->send_buf.data = kmalloc(len, GFP_KERNEL);
+		if (!tx_buf->send_buf.data) {
+			kfree(tx_buf);
+			goto	out;
+		}
+
+		spin_lock_irqsave(&cl->tx_free_list_spinlock, flags);
+		list_add_tail(&tx_buf->list, &cl->tx_free_list.list);
+		spin_unlock_irqrestore(&cl->tx_free_list_spinlock, flags);
+	}
+	return	0;
+out:
+	dev_err(&cl->device->dev, "error in allocating Tx pool\n");
+	ishtp_cl_free_rx_ring(cl);
+	return	-ENOMEM;
+}
+
+/**
+ * ishtp_cl_free_rx_ring() - Free RX ring buffers
+ * @cl: client device instance
+ *
+ * Free RX ring buffers
+ */
+void ishtp_cl_free_rx_ring(struct ishtp_cl *cl)
+{
+	struct ishtp_cl_rb *rb;
+	unsigned long	flags;
+
+	/* release allocated memory - pass over free_rb_list */
+	spin_lock_irqsave(&cl->free_list_spinlock, flags);
+	while (!list_empty(&cl->free_rb_list.list)) {
+		rb = list_entry(cl->free_rb_list.list.next, struct ishtp_cl_rb,
+				list);
+		list_del(&rb->list);
+		kfree(rb->buffer.data);
+		kfree(rb);
+	}
+	spin_unlock_irqrestore(&cl->free_list_spinlock, flags);
+	/* release allocated memory - pass over in_process_list */
+	spin_lock_irqsave(&cl->in_process_spinlock, flags);
+	while (!list_empty(&cl->in_process_list.list)) {
+		rb = list_entry(cl->in_process_list.list.next,
+				struct ishtp_cl_rb, list);
+		list_del(&rb->list);
+		kfree(rb->buffer.data);
+		kfree(rb);
+	}
+	spin_unlock_irqrestore(&cl->in_process_spinlock, flags);
+}
+
+/**
+ * ishtp_cl_free_tx_ring() - Free TX ring buffers
+ * @cl: client device instance
+ *
+ * Free TX ring buffers
+ */
+void ishtp_cl_free_tx_ring(struct ishtp_cl *cl)
+{
+	struct ishtp_cl_tx_ring	*tx_buf;
+	unsigned long	flags;
+
+	spin_lock_irqsave(&cl->tx_free_list_spinlock, flags);
+	/* release allocated memory - pass over tx_free_list */
+	while (!list_empty(&cl->tx_free_list.list)) {
+		tx_buf = list_entry(cl->tx_free_list.list.next,
+				    struct ishtp_cl_tx_ring, list);
+		list_del(&tx_buf->list);
+		kfree(tx_buf->send_buf.data);
+		kfree(tx_buf);
+	}
+	spin_unlock_irqrestore(&cl->tx_free_list_spinlock, flags);
+
+	spin_lock_irqsave(&cl->tx_list_spinlock, flags);
+	/* release allocated memory - pass over tx_list */
+	while (!list_empty(&cl->tx_list.list)) {
+		tx_buf = list_entry(cl->tx_list.list.next,
+				    struct ishtp_cl_tx_ring, list);
+		list_del(&tx_buf->list);
+		kfree(tx_buf->send_buf.data);
+		kfree(tx_buf);
+	}
+	spin_unlock_irqrestore(&cl->tx_list_spinlock, flags);
+}
+
+/**
+ * ishtp_io_rb_free() - Free IO request block
+ * @rb: IO request block
+ *
+ * Free io request block memory
+ */
+void ishtp_io_rb_free(struct ishtp_cl_rb *rb)
+{
+	if (rb == NULL)
+		return;
+
+	kfree(rb->buffer.data);
+	kfree(rb);
+}
+
+/**
+ * ishtp_io_rb_init() - Allocate and init IO request block
+ * @cl: client device instance
+ *
+ * Allocate and initialize request block
+ *
+ * Return: Allocted IO request block pointer
+ */
+struct ishtp_cl_rb *ishtp_io_rb_init(struct ishtp_cl *cl)
+{
+	struct ishtp_cl_rb *rb;
+
+	rb = kzalloc(sizeof(struct ishtp_cl_rb), GFP_KERNEL);
+	if (!rb)
+		return NULL;
+
+	INIT_LIST_HEAD(&rb->list);
+	rb->cl = cl;
+	rb->buf_idx = 0;
+	return rb;
+}
+
+/**
+ * ishtp_io_rb_alloc_buf() - Allocate and init response buffer
+ * @rb: IO request block
+ * @length: length of response buffer
+ *
+ * Allocate respose buffer
+ *
+ * Return: 0 on success else -ENOMEM
+ */
+int ishtp_io_rb_alloc_buf(struct ishtp_cl_rb *rb, size_t length)
+{
+	if (!rb)
+		return -EINVAL;
+
+	if (length == 0)
+		return 0;
+
+	rb->buffer.data = kmalloc(length, GFP_KERNEL);
+	if (!rb->buffer.data)
+		return -ENOMEM;
+
+	rb->buffer.size = length;
+	return 0;
+}
+
+/**
+ * ishtp_cl_io_rb_recycle() - Recycle IO request blocks
+ * @rb: IO request block
+ *
+ * Re-append rb to its client's free list and send flow control if needed
+ *
+ * Return: 0 on success else -EFAULT
+ */
+int ishtp_cl_io_rb_recycle(struct ishtp_cl_rb *rb)
+{
+	struct ishtp_cl *cl;
+	int	rets = 0;
+	unsigned long	flags;
+
+	if (!rb || !rb->cl)
+		return	-EFAULT;
+
+	cl = rb->cl;
+	spin_lock_irqsave(&cl->free_list_spinlock, flags);
+	list_add_tail(&rb->list, &cl->free_rb_list.list);
+	spin_unlock_irqrestore(&cl->free_list_spinlock, flags);
+
+	/*
+	 * If we returned the first buffer to empty 'free' list,
+	 * send flow control
+	 */
+	if (!cl->out_flow_ctrl_creds)
+		rets = ishtp_cl_read_start(cl);
+
+	return	rets;
+}
+EXPORT_SYMBOL(ishtp_cl_io_rb_recycle);

drivers/hid/intel-ish-hid/ishtp/client.h

+/*
+ * ISHTP client logic
+ *
+ * Copyright (c) 2003-2016, Intel Corporation.
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
+ * more details.
+ */
+
+#ifndef _ISHTP_CLIENT_H_
+#define _ISHTP_CLIENT_H_
+
+#include <linux/types.h>
+#include "ishtp-dev.h"
+
+/* Client state */
+enum cl_state {
+	ISHTP_CL_INITIALIZING = 0,
+	ISHTP_CL_CONNECTING,
+	ISHTP_CL_CONNECTED,
+	ISHTP_CL_DISCONNECTING,
+	ISHTP_CL_DISCONNECTED
+};
+
+/* Tx and Rx ring size */
+#define	CL_DEF_RX_RING_SIZE	2
+#define	CL_DEF_TX_RING_SIZE	2
+#define	CL_MAX_RX_RING_SIZE	32
+#define	CL_MAX_TX_RING_SIZE	32
+
+#define DMA_SLOT_SIZE		4096
+/* Number of IPC fragments after which it's worth sending via DMA */
+#define	DMA_WORTH_THRESHOLD	3
+
+/* DMA/IPC Tx paths. Other the default means enforcement */
+#define	CL_TX_PATH_DEFAULT	0
+#define	CL_TX_PATH_IPC		1
+#define	CL_TX_PATH_DMA		2
+
+/* Client Tx buffer list entry */
+struct ishtp_cl_tx_ring {
+	struct list_head	list;
+	struct ishtp_msg_data	send_buf;
+};
+
+/* ISHTP client instance */
+struct ishtp_cl {
+	struct list_head	link;
+	struct ishtp_device	*dev;
+	enum cl_state		state;
+	int			status;
+
+	/* Link to ISHTP bus device */
+	struct ishtp_cl_device	*device;
+
+	/* ID of client connected */
+	uint8_t	host_client_id;
+	uint8_t	fw_client_id;
+	uint8_t	ishtp_flow_ctrl_creds;
+	uint8_t	out_flow_ctrl_creds;
+
+	/* dma */
+	int	last_tx_path;
+	/* 0: ack wasn't received,1:ack was received */
+	int	last_dma_acked;
+	unsigned char	*last_dma_addr;
+	/* 0: ack wasn't received,1:ack was received */
+	int	last_ipc_acked;
+
+	/* Rx ring buffer pool */
+	unsigned int	rx_ring_size;
+	struct ishtp_cl_rb	free_rb_list;
+	spinlock_t	free_list_spinlock;
+	/* Rx in-process list */
+	struct ishtp_cl_rb	in_process_list;
+	spinlock_t	in_process_spinlock;
+
+	/* Client Tx buffers list */
+	unsigned int	tx_ring_size;
+	struct ishtp_cl_tx_ring	tx_list, tx_free_list;
+	spinlock_t	tx_list_spinlock;
+	spinlock_t	tx_free_list_spinlock;
+	size_t	tx_offs;	/* Offset in buffer at head of 'tx_list' */
+
+	/**
+	 * if we get a FC, and the list is not empty, we must know whether we
+	 * are at the middle of sending.
+	 * if so -need to increase FC counter, otherwise, need to start sending
+	 * the first msg in list
+	 * (!)This is for counting-FC implementation only. Within single-FC the
+	 * other party may NOT send FC until it receives complete message
+	 */
+	int	sending;
+
+	/* Send FC spinlock */
+	spinlock_t	fc_spinlock;
+
+	/* wait queue for connect and disconnect response from FW */
+	wait_queue_head_t	wait_ctrl_res;
+
+	/* Error stats */
+	unsigned int	err_send_msg;
+	unsigned int	err_send_fc;
+
+	/* Send/recv stats */
+	unsigned int	send_msg_cnt_ipc;
+	unsigned int	send_msg_cnt_dma;
+	unsigned int	recv_msg_cnt_ipc;
+	unsigned int	recv_msg_cnt_dma;
+	unsigned int	recv_msg_num_frags;
+	unsigned int	ishtp_flow_ctrl_cnt;
+	unsigned int	out_flow_ctrl_cnt;
+
+	/* Rx msg ... out FC timing */
+	struct timespec ts_rx;
+	struct timespec ts_out_fc;
+	struct timespec ts_max_fc_delay;
+	void *client_data;
+};
+
+/* Client connection managenment internal functions */
+int ishtp_can_client_connect(struct ishtp_device *ishtp_dev, uuid_le *uuid);
+int ishtp_fw_cl_by_id(struct ishtp_device *dev, uint8_t client_id);
+void ishtp_cl_send_msg(struct ishtp_device *dev, struct ishtp_cl *cl);
+void recv_ishtp_cl_msg(struct ishtp_device *dev,
+		       struct ishtp_msg_hdr *ishtp_hdr);
+int ishtp_cl_read_start(struct ishtp_cl *cl);
+
+/* Ring Buffer I/F */
+int ishtp_cl_alloc_rx_ring(struct ishtp_cl *cl);
+int ishtp_cl_alloc_tx_ring(struct ishtp_cl *cl);
+void ishtp_cl_free_rx_ring(struct ishtp_cl *cl);
+void ishtp_cl_free_tx_ring(struct ishtp_cl *cl);
+
+/* DMA I/F functions */
+void recv_ishtp_cl_msg_dma(struct ishtp_device *dev, void *msg,
+			   struct dma_xfer_hbm *hbm);
+void ishtp_cl_alloc_dma_buf(struct ishtp_device *dev);
+void ishtp_cl_free_dma_buf(struct ishtp_device *dev);
+void *ishtp_cl_get_dma_send_buf(struct ishtp_device *dev,
+				uint32_t size);
+void ishtp_cl_release_dma_acked_mem(struct ishtp_device *dev,
+				    void *msg_addr,
+				    uint8_t size);
+
+/* Request blocks alloc/free I/F */
+struct ishtp_cl_rb *ishtp_io_rb_init(struct ishtp_cl *cl);
+void ishtp_io_rb_free(struct ishtp_cl_rb *priv_rb);
+int ishtp_io_rb_alloc_buf(struct ishtp_cl_rb *rb, size_t length);
+
+/**
+ * ishtp_cl_cmp_id - tells if file private data have same id
+ * returns true  - if ids are the same and not NULL
+ */
+static inline bool ishtp_cl_cmp_id(const struct ishtp_cl *cl1,
+				   const struct ishtp_cl *cl2)
+{
+	return cl1 && cl2 &&
+		(cl1->host_client_id == cl2->host_client_id) &&
+		(cl1->fw_client_id == cl2->fw_client_id);
+}
+
+/* exported functions from ISHTP under client management scope */
+struct ishtp_cl	*ishtp_cl_allocate(struct ishtp_device *dev);
+void ishtp_cl_free(struct ishtp_cl *cl);
+int ishtp_cl_link(struct ishtp_cl *cl, int id);
+void ishtp_cl_unlink(struct ishtp_cl *cl);
+int ishtp_cl_disconnect(struct ishtp_cl *cl);
+int ishtp_cl_connect(struct ishtp_cl *cl);
+int ishtp_cl_send(struct ishtp_cl *cl, uint8_t *buf, size_t length);
+int ishtp_cl_flush_queues(struct ishtp_cl *cl);
+
+/* exported functions from ISHTP client buffer management scope */
+int ishtp_cl_io_rb_recycle(struct ishtp_cl_rb *rb);
+
+#endif /* _ISHTP_CLIENT_H_ */

drivers/hid/intel-ish-hid/ishtp/dma-if.c

+/*
+ * ISHTP DMA I/F functions
+ *
+ * Copyright (c) 2003-2016, Intel Corporation.
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
+ * more details.
+ *
+ */
+
+#include <linux/slab.h>
+#include <linux/sched.h>
+#include <linux/wait.h>
+#include <linux/delay.h>
+#include <linux/dma-mapping.h>
+#include "ishtp-dev.h"
+#include "client.h"
+
+/**
+ * ishtp_cl_alloc_dma_buf() - Allocate DMA RX and TX buffer
+ * @dev: ishtp device
+ *
+ * Allocate RX and TX DMA buffer once during bus setup.
+ * It allocates 1MB, RX and TX DMA buffer, which are divided
+ * into slots.
+ */
+void	ishtp_cl_alloc_dma_buf(struct ishtp_device *dev)
+{
+	dma_addr_t	h;
+
+	if (dev->ishtp_host_dma_tx_buf)
+		return;
+
+	dev->ishtp_host_dma_tx_buf_size = 1024*1024;
+	dev->ishtp_host_dma_rx_buf_size = 1024*1024;
+
+	/* Allocate Tx buffer and init usage bitmap */
+	dev->ishtp_host_dma_tx_buf = dma_alloc_coherent(dev->devc,
+					dev->ishtp_host_dma_tx_buf_size,
+					&h, GFP_KERNEL);
+	if (dev->ishtp_host_dma_tx_buf)
+		dev->ishtp_host_dma_tx_buf_phys = h;
+
+	dev->ishtp_dma_num_slots = dev->ishtp_host_dma_tx_buf_size /
+						DMA_SLOT_SIZE;
+
+	dev->ishtp_dma_tx_map = kcalloc(dev->ishtp_dma_num_slots,
+					sizeof(uint8_t),
+					GFP_KERNEL);
+	spin_lock_init(&dev->ishtp_dma_tx_lock);
+
+	/* Allocate Rx buffer */
+	dev->ishtp_host_dma_rx_buf = dma_alloc_coherent(dev->devc,
+					dev->ishtp_host_dma_rx_buf_size,
+					 &h, GFP_KERNEL);
+
+	if (dev->ishtp_host_dma_rx_buf)
+		dev->ishtp_host_dma_rx_buf_phys = h;
+}
+
+/**
+ * ishtp_cl_free_dma_buf() - Free DMA RX and TX buffer
+ * @dev: ishtp device
+ *
+ * Free DMA buffer when all clients are released. This is
+ * only happens during error path in ISH built in driver
+ * model
+ */
+void	ishtp_cl_free_dma_buf(struct ishtp_device *dev)
+{
+	dma_addr_t	h;
+
+	if (dev->ishtp_host_dma_tx_buf) {
+		h = dev->ishtp_host_dma_tx_buf_phys;
+		dma_free_coherent(dev->devc, dev->ishtp_host_dma_tx_buf_size,
+				  dev->ishtp_host_dma_tx_buf, h);
+	}
+
+	if (dev->ishtp_host_dma_rx_buf) {
+		h = dev->ishtp_host_dma_rx_buf_phys;
+		dma_free_coherent(dev->devc, dev->ishtp_host_dma_rx_buf_size,
+				  dev->ishtp_host_dma_rx_buf, h);
+	}
+
+	kfree(dev->ishtp_dma_tx_map);
+	dev->ishtp_host_dma_tx_buf = NULL;
+	dev->ishtp_host_dma_rx_buf = NULL;
+	dev->ishtp_dma_tx_map = NULL;
+}
+
+/*
+ * ishtp_cl_get_dma_send_buf() - Get a DMA memory slot
+ * @dev:	ishtp device
+ * @size:	Size of memory to get
+ *
+ * Find and return free address of "size" bytes in dma tx buffer.
+ * the function will mark this address as "in-used" memory.
+ *
+ * Return: NULL when no free buffer else a buffer to copy
+ */
+void *ishtp_cl_get_dma_send_buf(struct ishtp_device *dev,
+				uint32_t size)
+{
+	unsigned long	flags;
+	int i, j, free;
+	/* additional slot is needed if there is rem */
+	int required_slots = (size / DMA_SLOT_SIZE)
+		+ 1 * (size % DMA_SLOT_SIZE != 0);
+
+	spin_lock_irqsave(&dev->ishtp_dma_tx_lock, flags);
+	for (i = 0; i <= (dev->ishtp_dma_num_slots - required_slots); i++) {
+		free = 1;
+		for (j = 0; j < required_slots; j++)
+			if (dev->ishtp_dma_tx_map[i+j]) {
+				free = 0;
+				i += j;
+				break;
+			}
+		if (free) {
+			/* mark memory as "caught" */
+			for (j = 0; j < required_slots; j++)
+				dev->ishtp_dma_tx_map[i+j] = 1;
+			spin_unlock_irqrestore(&dev->ishtp_dma_tx_lock, flags);
+			return (i * DMA_SLOT_SIZE) +
+				(unsigned char *)dev->ishtp_host_dma_tx_buf;
+		}
+	}
+	spin_unlock_irqrestore(&dev->ishtp_dma_tx_lock, flags);
+	dev_err(dev->devc, "No free DMA buffer to send msg\n");
+	return NULL;
+}
+
+/*
+ * ishtp_cl_release_dma_acked_mem() - Release DMA memory slot
+ * @dev:	ishtp device
+ * @msg_addr:	message address of slot
+ * @size:	Size of memory to get
+ *
+ * Release_dma_acked_mem - returnes the acked memory to free list.
+ * (from msg_addr, size bytes long)
+ */
+void ishtp_cl_release_dma_acked_mem(struct ishtp_device *dev,
+				    void *msg_addr,
+				    uint8_t size)
+{
+	unsigned long	flags;
+	int acked_slots = (size / DMA_SLOT_SIZE)
+		+ 1 * (size % DMA_SLOT_SIZE != 0);
+	int i, j;
+
+	if ((msg_addr - dev->ishtp_host_dma_tx_buf) % DMA_SLOT_SIZE) {
+		dev_err(dev->devc, "Bad DMA Tx ack address\n");
+		return;
+	}
+
+	i = (msg_addr - dev->ishtp_host_dma_tx_buf) / DMA_SLOT_SIZE;
+	spin_lock_irqsave(&dev->ishtp_dma_tx_lock, flags);
+	for (j = 0; j < acked_slots; j++) {
+		if ((i + j) >= dev->ishtp_dma_num_slots ||
+					!dev->ishtp_dma_tx_map[i+j]) {
+			/* no such slot, or memory is already free */
+			spin_unlock_irqrestore(&dev->ishtp_dma_tx_lock, flags);
+			dev_err(dev->devc, "Bad DMA Tx ack address\n");
+			return;
+		}
+		dev->ishtp_dma_tx_map[i+j] = 0;
+	}
+	spin_unlock_irqrestore(&dev->ishtp_dma_tx_lock, flags);
+}

drivers/hid/intel-ish-hid/ishtp/hbm.h

+/*
+ * ISHTP bus layer messages handling
+ *
+ * Copyright (c) 2003-2016, Intel Corporation.
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
+ * more details.
+ */
+
+#ifndef _ISHTP_HBM_H_
+#define _ISHTP_HBM_H_
+
+#include <linux/uuid.h>
+
+struct ishtp_device;
+struct ishtp_msg_hdr;
+struct ishtp_cl;
+
+/*
+ * Timeouts in Seconds
+ */
+#define ISHTP_INTEROP_TIMEOUT		7 /* Timeout on ready message */
+
+#define ISHTP_CL_CONNECT_TIMEOUT	15 /* HPS: Client Connect Timeout */
+
+/*
+ * ISHTP Version
+ */
+#define HBM_MINOR_VERSION		0
+#define HBM_MAJOR_VERSION		1
+
+/* Host bus message command opcode */
+#define ISHTP_HBM_CMD_OP_MSK		0x7f
+/* Host bus message command RESPONSE */
+#define ISHTP_HBM_CMD_RES_MSK		0x80
+
+/*
+ * ISHTP Bus Message Command IDs
+ */
+#define HOST_START_REQ_CMD		0x01
+#define HOST_START_RES_CMD		0x81
+
+#define HOST_STOP_REQ_CMD		0x02
+#define HOST_STOP_RES_CMD		0x82
+
+#define FW_STOP_REQ_CMD			0x03
+
+#define HOST_ENUM_REQ_CMD		0x04
+#define HOST_ENUM_RES_CMD		0x84
+
+#define HOST_CLIENT_PROPERTIES_REQ_CMD	0x05
+#define HOST_CLIENT_PROPERTIES_RES_CMD	0x85
+
+#define CLIENT_CONNECT_REQ_CMD		0x06
+#define CLIENT_CONNECT_RES_CMD		0x86
+
+#define CLIENT_DISCONNECT_REQ_CMD	0x07
+#define CLIENT_DISCONNECT_RES_CMD	0x87
+
+#define ISHTP_FLOW_CONTROL_CMD		0x08
+
+#define DMA_BUFFER_ALLOC_NOTIFY		0x11
+#define DMA_BUFFER_ALLOC_RESPONSE	0x91
+
+#define DMA_XFER			0x12
+#define DMA_XFER_ACK			0x92
+
+/*
+ * ISHTP Stop Reason
+ * used by hbm_host_stop_request.reason
+ */
+#define	DRIVER_STOP_REQUEST		0x00
+
+/*
+ * ISHTP BUS Interface Section
+ */
+struct ishtp_msg_hdr {
+	uint32_t fw_addr:8;
+	uint32_t host_addr:8;
+	uint32_t length:9;
+	uint32_t reserved:6;
+	uint32_t msg_complete:1;
+} __packed;
+
+struct ishtp_bus_message {
+	uint8_t hbm_cmd;
+	uint8_t data[0];
+} __packed;
+
+/**
+ * struct hbm_cl_cmd - client specific host bus command
+ *	CONNECT, DISCONNECT, and FlOW CONTROL
+ *
+ * @hbm_cmd - bus message command header
+ * @fw_addr - address of the fw client
+ * @host_addr - address of the client in the driver
+ * @data
+ */
+struct ishtp_hbm_cl_cmd {
+	uint8_t hbm_cmd;
+	uint8_t fw_addr;
+	uint8_t host_addr;
+	uint8_t data;
+};
+
+struct hbm_version {
+	uint8_t minor_version;
+	uint8_t major_version;
+} __packed;
+
+struct hbm_host_version_request {
+	uint8_t hbm_cmd;
+	uint8_t reserved;
+	struct hbm_version host_version;
+} __packed;
+
+struct hbm_host_version_response {
+	uint8_t hbm_cmd;
+	uint8_t host_version_supported;
+	struct hbm_version fw_max_version;
+} __packed;
+
+struct hbm_host_stop_request {
+	uint8_t hbm_cmd;
+	uint8_t reason;
+	uint8_t reserved[2];
+} __packed;
+
+struct hbm_host_stop_response {
+	uint8_t hbm_cmd;
+	uint8_t reserved[3];
+} __packed;
+
+struct hbm_host_enum_request {
+	uint8_t hbm_cmd;
+	uint8_t reserved[3];
+} __packed;
+
+struct hbm_host_enum_response {
+	uint8_t hbm_cmd;
+	uint8_t reserved[3];
+	uint8_t valid_addresses[32];
+} __packed;
+
+struct ishtp_client_properties {
+	uuid_le protocol_name;
+	uint8_t protocol_version;
+	uint8_t max_number_of_connections;
+	uint8_t fixed_address;
+	uint8_t single_recv_buf;
+	uint32_t max_msg_length;
+	uint8_t dma_hdr_len;
+#define	ISHTP_CLIENT_DMA_ENABLED	0x80
+	uint8_t reserved4;
+	uint8_t reserved5;
+	uint8_t reserved6;
+} __packed;
+
+struct hbm_props_request {
+	uint8_t hbm_cmd;
+	uint8_t address;
+	uint8_t reserved[2];
+} __packed;
+
+struct hbm_props_response {
+	uint8_t hbm_cmd;
+	uint8_t address;
+	uint8_t status;
+	uint8_t reserved[1];
+	struct ishtp_client_properties client_properties;
+} __packed;
+
+/**
+ * struct hbm_client_connect_request - connect/disconnect request
+ *
+ * @hbm_cmd - bus message command header
+ * @fw_addr - address of the fw client
+ * @host_addr - address of the client in the driver
+ * @reserved
+ */
+struct hbm_client_connect_request {
+	uint8_t hbm_cmd;
+	uint8_t fw_addr;
+	uint8_t host_addr;
+	uint8_t reserved;
+} __packed;
+
+/**
+ * struct hbm_client_connect_response - connect/disconnect response
+ *
+ * @hbm_cmd - bus message command header
+ * @fw_addr - address of the fw client
+ * @host_addr - address of the client in the driver
+ * @status - status of the request
+ */
+struct hbm_client_connect_response {
+	uint8_t hbm_cmd;
+	uint8_t fw_addr;
+	uint8_t host_addr;
+	uint8_t status;
+} __packed;
+
+
+#define ISHTP_FC_MESSAGE_RESERVED_LENGTH		5
+
+struct hbm_flow_control {
+	uint8_t hbm_cmd;
+	uint8_t fw_addr;
+	uint8_t host_addr;
+	uint8_t reserved[ISHTP_FC_MESSAGE_RESERVED_LENGTH];
+} __packed;
+
+struct dma_alloc_notify {
+	uint8_t hbm;
+	uint8_t status;
+	uint8_t reserved[2];
+	uint32_t buf_size;
+	uint64_t buf_address;
+	/* [...] May come more size/address pairs */
+} __packed;
+
+struct dma_xfer_hbm {
+	uint8_t hbm;
+	uint8_t fw_client_id;
+	uint8_t host_client_id;
+	uint8_t reserved;
+	uint64_t msg_addr;
+	uint32_t msg_length;
+	uint32_t reserved2;
+} __packed;
+
+/* System state */
+#define ISHTP_SYSTEM_STATE_CLIENT_ADDR		13
+
+#define SYSTEM_STATE_SUBSCRIBE			0x1
+#define SYSTEM_STATE_STATUS			0x2
+#define SYSTEM_STATE_QUERY_SUBSCRIBERS		0x3
+#define SYSTEM_STATE_STATE_CHANGE_REQ		0x4
+/*indicates suspend and resume states*/
+#define SUSPEND_STATE_BIT			(1<<1)
+
+struct ish_system_states_header {
+	uint32_t cmd;
+	uint32_t cmd_status;	/*responses will have this set*/
+} __packed;
+
+struct ish_system_states_subscribe {
+	struct ish_system_states_header hdr;
+	uint32_t states;
+} __packed;
+
+struct ish_system_states_status {
+	struct ish_system_states_header hdr;
+	uint32_t supported_states;
+	uint32_t states_status;
+} __packed;
+
+struct ish_system_states_query_subscribers {
+	struct ish_system_states_header hdr;
+} __packed;
+
+struct ish_system_states_state_change_req {
+	struct ish_system_states_header hdr;
+	uint32_t requested_states;
+	uint32_t states_status;
+} __packed;
+
+/**
+ * enum ishtp_hbm_state - host bus message protocol state
+ *
+ * @ISHTP_HBM_IDLE : protocol not started
+ * @ISHTP_HBM_START : start request message was sent
+ * @ISHTP_HBM_ENUM_CLIENTS : enumeration request was sent
+ * @ISHTP_HBM_CLIENT_PROPERTIES : acquiring clients properties
+ */
+enum ishtp_hbm_state {
+	ISHTP_HBM_IDLE = 0,
+	ISHTP_HBM_START,
+	ISHTP_HBM_STARTED,
+	ISHTP_HBM_ENUM_CLIENTS,
+	ISHTP_HBM_CLIENT_PROPERTIES,
+	ISHTP_HBM_WORKING,
+	ISHTP_HBM_STOPPED,
+};
+
+static inline void ishtp_hbm_hdr(struct ishtp_msg_hdr *hdr, size_t length)
+{
+	hdr->host_addr = 0;
+	hdr->fw_addr = 0;
+	hdr->length = length;
+	hdr->msg_complete = 1;
+	hdr->reserved = 0;
+}
+
+int ishtp_hbm_start_req(struct ishtp_device *dev);
+int ishtp_hbm_start_wait(struct ishtp_device *dev);
+int ishtp_hbm_cl_flow_control_req(struct ishtp_device *dev,
+				  struct ishtp_cl *cl);
+int ishtp_hbm_cl_disconnect_req(struct ishtp_device *dev, struct ishtp_cl *cl);
+int ishtp_hbm_cl_connect_req(struct ishtp_device *dev, struct ishtp_cl *cl);
+void ishtp_hbm_enum_clients_req(struct ishtp_device *dev);
+void bh_hbm_work_fn(struct work_struct *work);
+void recv_hbm(struct ishtp_device *dev, struct ishtp_msg_hdr *ishtp_hdr);
+void recv_fixed_cl_msg(struct ishtp_device *dev,
+	struct ishtp_msg_hdr *ishtp_hdr);
+void ishtp_hbm_dispatch(struct ishtp_device *dev,
+	struct ishtp_bus_message *hdr);
+
+void ishtp_query_subscribers(struct ishtp_device *dev);
+
+/* Exported I/F */
+void ishtp_send_suspend(struct ishtp_device *dev);
+void ishtp_send_resume(struct ishtp_device *dev);
+
+#endif /* _ISHTP_HBM_H_ */

drivers/hid/intel-ish-hid/ishtp/init.c

+/*
+ * Initialization protocol for ISHTP driver
+ *
+ * Copyright (c) 2003-2016, Intel Corporation.
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
+ * more details.
+ */
+
+#include <linux/export.h>
+#include <linux/slab.h>
+#include <linux/sched.h>
+#include <linux/miscdevice.h>
+#include "ishtp-dev.h"
+#include "hbm.h"
+#include "client.h"
+
+/**
+ * ishtp_dev_state_str() -Convert to string format
+ * @state: state to convert
+ *
+ * Convert state to string for prints
+ *
+ * Return: character pointer to converted string
+ */
+const char *ishtp_dev_state_str(int state)
+{
+	switch (state) {
+	case ISHTP_DEV_INITIALIZING:
+		return	"INITIALIZING";
+	case ISHTP_DEV_INIT_CLIENTS:
+		return	"INIT_CLIENTS";
+	case ISHTP_DEV_ENABLED:
+		return	"ENABLED";
+	case ISHTP_DEV_RESETTING:
+		return	"RESETTING";
+	case ISHTP_DEV_DISABLED:
+		return	"DISABLED";
+	case ISHTP_DEV_POWER_DOWN:
+		return	"POWER_DOWN";
+	case ISHTP_DEV_POWER_UP:
+		return	"POWER_UP";
+	default:
+		return "unknown";
+	}
+}
+
+/**
+ * ishtp_device_init() - ishtp device init
+ * @dev: ISHTP device instance
+ *
+ * After ISHTP device is alloacted, this function is used to initialize
+ * each field which includes spin lock, work struct and lists
+ */
+void ishtp_device_init(struct ishtp_device *dev)
+{
+	dev->dev_state = ISHTP_DEV_INITIALIZING;
+	INIT_LIST_HEAD(&dev->cl_list);
+	INIT_LIST_HEAD(&dev->device_list);
+	dev->rd_msg_fifo_head = 0;
+	dev->rd_msg_fifo_tail = 0;
+	spin_lock_init(&dev->rd_msg_spinlock);
+
+	init_waitqueue_head(&dev->wait_hbm_recvd_msg);
+	spin_lock_init(&dev->read_list_spinlock);
+	spin_lock_init(&dev->device_lock);
+	spin_lock_init(&dev->device_list_lock);
+	spin_lock_init(&dev->cl_list_lock);
+	spin_lock_init(&dev->fw_clients_lock);
+	INIT_WORK(&dev->bh_hbm_work, bh_hbm_work_fn);
+
+	bitmap_zero(dev->host_clients_map, ISHTP_CLIENTS_MAX);
+	dev->open_handle_count = 0;
+
+	/*
+	 * Reserving client ID 0 for ISHTP Bus Message communications
+	 */
+	bitmap_set(dev->host_clients_map, 0, 1);
+
+	INIT_LIST_HEAD(&dev->read_list.list);
+
+}
+EXPORT_SYMBOL(ishtp_device_init);
+
+/**
+ * ishtp_start() - Start ISH processing
+ * @dev: ISHTP device instance
+ *
+ * Start ISHTP processing by sending query subscriber message
+ *
+ * Return: 0 on success else -ENODEV
+ */
+int ishtp_start(struct ishtp_device *dev)
+{
+	if (ishtp_hbm_start_wait(dev)) {
+		dev_err(dev->devc, "HBM haven't started");
+		goto err;
+	}
+
+	/* suspend & resume notification - send QUERY_SUBSCRIBERS msg */
+	ishtp_query_subscribers(dev);
+
+	return 0;
+err:
+	dev_err(dev->devc, "link layer initialization failed.\n");
+	dev->dev_state = ISHTP_DEV_DISABLED;
+	return -ENODEV;
+}
+EXPORT_SYMBOL(ishtp_start);

drivers/hid/intel-ish-hid/ishtp/ishtp-dev.h

+/*
+ * Most ISHTP provider device and ISHTP logic declarations
+ *
+ * Copyright (c) 2003-2016, Intel Corporation.
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
+ * more details.
+ */
+
+#ifndef _ISHTP_DEV_H_
+#define _ISHTP_DEV_H_
+
+#include <linux/types.h>
+#include <linux/spinlock.h>
+#include "bus.h"
+#include "hbm.h"
+
+#define	IPC_PAYLOAD_SIZE	128
+#define ISHTP_RD_MSG_BUF_SIZE	IPC_PAYLOAD_SIZE
+#define	IPC_FULL_MSG_SIZE	132
+
+/* Number of messages to be held in ISR->BH FIFO */
+#define	RD_INT_FIFO_SIZE	64
+
+/*
+ * Number of IPC messages to be held in Tx FIFO, to be sent by ISR -
+ * Tx complete interrupt or RX_COMPLETE handler
+ */
+#define	IPC_TX_FIFO_SIZE	512
+
+/*
+ * Number of Maximum ISHTP Clients
+ */
+#define ISHTP_CLIENTS_MAX 256
+
+/*
+ * Number of File descriptors/handles
+ * that can be opened to the driver.
+ *
+ * Limit to 255: 256 Total Clients
+ * minus internal client for ISHTP Bus Messages
+ */
+#define ISHTP_MAX_OPEN_HANDLE_COUNT (ISHTP_CLIENTS_MAX - 1)
+
+/* Internal Clients Number */
+#define ISHTP_HOST_CLIENT_ID_ANY		(-1)
+#define ISHTP_HBM_HOST_CLIENT_ID		0
+
+#define	MAX_DMA_DELAY	20
+
+/* ISHTP device states */
+enum ishtp_dev_state {
+	ISHTP_DEV_INITIALIZING = 0,
+	ISHTP_DEV_INIT_CLIENTS,
+	ISHTP_DEV_ENABLED,
+	ISHTP_DEV_RESETTING,
+	ISHTP_DEV_DISABLED,
+	ISHTP_DEV_POWER_DOWN,
+	ISHTP_DEV_POWER_UP
+};
+const char *ishtp_dev_state_str(int state);
+
+struct ishtp_cl;
+
+/**
+ * struct ishtp_fw_client - representation of fw client
+ *
+ * @props - client properties
+ * @client_id - fw client id
+ */
+struct ishtp_fw_client {
+	struct ishtp_client_properties props;
+	uint8_t client_id;
+};
+
+/**
+ * struct ishtp_msg_data - ISHTP message data struct
+ * @size:	Size of data in the *data
+ * @data:	Pointer to data
+ */
+struct ishtp_msg_data {
+	uint32_t size;
+	unsigned char *data;
+};
+
+/*
+ * struct ishtp_cl_rb - request block structure
+ * @list:	Link to list members
+ * @cl:		ISHTP client instance
+ * @buffer:	message header
+ * @buf_idx:	Index into buffer
+ * @read_time:	 unused at this time
+ */
+struct ishtp_cl_rb {
+	struct list_head list;
+	struct ishtp_cl *cl;
+	struct ishtp_msg_data buffer;
+	unsigned long buf_idx;
+	unsigned long read_time;
+};
+
+/*
+ * Control info for IPC messages ISHTP/IPC sending FIFO -
+ * list with inline data buffer
+ * This structure will be filled with parameters submitted
+ * by the caller glue layer
+ * 'buf' may be pointing to the external buffer or to 'inline_data'
+ * 'offset' will be initialized to 0 by submitting
+ *
+ * 'ipc_send_compl' is intended for use by clients that send fragmented
+ * messages. When a fragment is sent down to IPC msg regs,
+ * it will be called.
+ * If it has more fragments to send, it will do it. With last fragment
+ * it will send appropriate ISHTP "message-complete" flag.
+ * It will remove the outstanding message
+ * (mark outstanding buffer as available).
+ * If counting flow control is in work and there are more flow control
+ * credits, it can put the next client message queued in cl.
+ * structure for IPC processing.
+ *
+ */
+struct wr_msg_ctl_info {
+	/* Will be called with 'ipc_send_compl_prm' as parameter */
+	void (*ipc_send_compl)(void *);
+
+	void *ipc_send_compl_prm;
+	size_t length;
+	struct list_head	link;
+	unsigned char	inline_data[IPC_FULL_MSG_SIZE];
+};
+
+/*
+ * The ISHTP layer talks to hardware IPC message using the following
+ * callbacks
+ */
+struct ishtp_hw_ops {
+	int	(*hw_reset)(struct ishtp_device *dev);
+	int	(*ipc_reset)(struct ishtp_device *dev);
+	uint32_t (*ipc_get_header)(struct ishtp_device *dev, int length,
+				   int busy);
+	int	(*write)(struct ishtp_device *dev,
+		void (*ipc_send_compl)(void *), void *ipc_send_compl_prm,
+		unsigned char *msg, int length);
+	uint32_t	(*ishtp_read_hdr)(const struct ishtp_device *dev);
+	int	(*ishtp_read)(struct ishtp_device *dev, unsigned char *buffer,
+			unsigned long buffer_length);
+	uint32_t	(*get_fw_status)(struct ishtp_device *dev);
+	void	(*sync_fw_clock)(struct ishtp_device *dev);
+};
+
+/**
+ * struct ishtp_device - ISHTP private device struct
+ */
+struct ishtp_device {
+	struct device *devc;	/* pointer to lowest device */
+	struct pci_dev *pdev;	/* PCI device to get device ids */
+
+	/* waitq for waiting for suspend response */
+	wait_queue_head_t suspend_wait;
+	bool suspend_flag;	/* Suspend is active */
+
+	/* waitq for waiting for resume response */
+	wait_queue_head_t resume_wait;
+	bool resume_flag;	/*Resume is active */
+
+	/*
+	 * lock for the device, for everything that doesn't have
+	 * a dedicated spinlock
+	 */
+	spinlock_t device_lock;
+
+	bool recvd_hw_ready;
+	struct hbm_version version;
+	int transfer_path; /* Choice of transfer path: IPC or DMA */
+
+	/* ishtp device states */
+	enum ishtp_dev_state dev_state;
+	enum ishtp_hbm_state hbm_state;
+
+	/* driver read queue */
+	struct ishtp_cl_rb read_list;
+	spinlock_t read_list_spinlock;
+
+	/* list of ishtp_cl's */
+	struct list_head cl_list;
+	spinlock_t cl_list_lock;
+	long open_handle_count;
+
+	/* List of bus devices */
+	struct list_head device_list;
+	spinlock_t device_list_lock;
+
+	/* waiting queues for receive message from FW */
+	wait_queue_head_t wait_hw_ready;
+	wait_queue_head_t wait_hbm_recvd_msg;
+
+	/* FIFO for input messages for BH processing */
+	unsigned char rd_msg_fifo[RD_INT_FIFO_SIZE * IPC_PAYLOAD_SIZE];
+	unsigned int rd_msg_fifo_head, rd_msg_fifo_tail;
+	spinlock_t rd_msg_spinlock;
+	struct work_struct bh_hbm_work;
+
+	/* IPC write queue */
+	struct wr_msg_ctl_info wr_processing_list_head, wr_free_list_head;
+	/* For both processing list  and free list */
+	spinlock_t wr_processing_spinlock;
+
+	spinlock_t out_ipc_spinlock;
+
+	struct ishtp_fw_client *fw_clients; /*Note:memory has to be allocated*/
+	DECLARE_BITMAP(fw_clients_map, ISHTP_CLIENTS_MAX);
+	DECLARE_BITMAP(host_clients_map, ISHTP_CLIENTS_MAX);
+	uint8_t fw_clients_num;
+	uint8_t fw_client_presentation_num;
+	uint8_t fw_client_index;
+	spinlock_t fw_clients_lock;
+
+	/* TX DMA buffers and slots */
+	int ishtp_host_dma_enabled;
+	void *ishtp_host_dma_tx_buf;
+	unsigned int ishtp_host_dma_tx_buf_size;
+	uint64_t ishtp_host_dma_tx_buf_phys;
+	int ishtp_dma_num_slots;
+
+	/* map of 4k blocks in Tx dma buf: 0-free, 1-used */
+	uint8_t *ishtp_dma_tx_map;
+	spinlock_t ishtp_dma_tx_lock;
+
+	/* RX DMA buffers and slots */
+	void *ishtp_host_dma_rx_buf;
+	unsigned int ishtp_host_dma_rx_buf_size;
+	uint64_t ishtp_host_dma_rx_buf_phys;
+
+	/* Dump to trace buffers if enabled*/
+	void (*print_log)(struct ishtp_device *dev, char *format, ...);
+
+	/* Debug stats */
+	unsigned int	ipc_rx_cnt;
+	unsigned long long	ipc_rx_bytes_cnt;
+	unsigned int	ipc_tx_cnt;
+	unsigned long long	ipc_tx_bytes_cnt;
+
+	const struct ishtp_hw_ops *ops;
+	size_t	mtu;
+	uint32_t	ishtp_msg_hdr;
+	char hw[0] __aligned(sizeof(void *));
+};
+
+static inline unsigned long ishtp_secs_to_jiffies(unsigned long sec)
+{
+	return msecs_to_jiffies(sec * MSEC_PER_SEC);
+}
+
+/*
+ * Register Access Function
+ */
+static inline int ish_ipc_reset(struct ishtp_device *dev)
+{
+	return dev->ops->ipc_reset(dev);
+}
+
+static inline int ish_hw_reset(struct ishtp_device *dev)
+{
+	return dev->ops->hw_reset(dev);
+}
+
+/* Exported function */
+void	ishtp_device_init(struct ishtp_device *dev);
+int	ishtp_start(struct ishtp_device *dev);
+
+#endif /*_ISHTP_DEV_H_*/