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>

1 files changed, 258 insertions, 0 deletions

diff --git a/drivers/hid/intel-ish-hid/ishtp/client-buffers.c b/drivers/hid/intel-ish-hid/ishtp/client-buffers.c
new file mode 100644
index 000000000000..3f5ce5ee687e
--- /dev/null
+++ b/drivers/hid/intel-ish-hid/ishtp/client-buffers.c
@@ -0,0 +1,258 @@
+/*
+ * 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);