// SPDX-License-Identifier: GPL-2.0-only
/*
* HSI character device driver, implements the character device
* interface.
*
* Copyright (C) 2010 Nokia Corporation. All rights reserved.
*
* Contact: Andras Domokos <[email protected]>
*/
#include <linux/errno.h>
#include <linux/types.h>
#include <linux/atomic.h>
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/module.h>
#include <linux/mutex.h>
#include <linux/list.h>
#include <linux/slab.h>
#include <linux/kmemleak.h>
#include <linux/ioctl.h>
#include <linux/wait.h>
#include <linux/fs.h>
#include <linux/sched.h>
#include <linux/device.h>
#include <linux/cdev.h>
#include <linux/uaccess.h>
#include <linux/scatterlist.h>
#include <linux/stat.h>
#include <linux/hsi/hsi.h>
#include <linux/hsi/hsi_char.h>
#define HSC_DEVS 16 /* Num of channels */
#define HSC_MSGS 4
#define HSC_RXBREAK 0
#define HSC_ID_BITS 6
#define HSC_PORT_ID_BITS 4
#define HSC_ID_MASK 3
#define HSC_PORT_ID_MASK 3
#define HSC_CH_MASK 0xf
/*
* We support up to 4 controllers that can have up to 4
* ports, which should currently be more than enough.
*/
#define HSC_BASEMINOR(id, port_id) \
((((id) & HSC_ID_MASK) << HSC_ID_BITS) | \
(((port_id) & HSC_PORT_ID_MASK) << HSC_PORT_ID_BITS))
enum {
HSC_CH_OPEN,
HSC_CH_READ,
HSC_CH_WRITE,
HSC_CH_WLINE,
};
enum {
HSC_RX,
HSC_TX,
};
struct hsc_client_data;
/**
* struct hsc_channel - hsi_char internal channel data
* @ch: channel number
* @flags: Keeps state of the channel (open/close, reading, writing)
* @free_msgs_list: List of free HSI messages/requests
* @rx_msgs_queue: List of pending RX requests
* @tx_msgs_queue: List of pending TX requests
* @lock: Serialize access to the lists
* @cl: reference to the associated hsi_client
* @cl_data: reference to the client data that this channels belongs to
* @rx_wait: RX requests wait queue
* @tx_wait: TX requests wait queue
*/
struct hsc_channel {
unsigned int ch;
unsigned long flags;
struct list_head free_msgs_list;
struct list_head rx_msgs_queue;
struct list_head tx_msgs_queue;
spinlock_t lock;
struct hsi_client *cl;
struct hsc_client_data *cl_data;
wait_queue_head_t rx_wait;
wait_queue_head_t tx_wait;
};
/**
* struct hsc_client_data - hsi_char internal client data
* @cdev: Characther device associated to the hsi_client
* @lock: Lock to serialize open/close access
* @flags: Keeps track of port state (rx hwbreak armed)
* @usecnt: Use count for claiming the HSI port (mutex protected)
* @cl: Referece to the HSI client
* @channels: Array of channels accessible by the client
*/
struct hsc_client_data {
struct cdev cdev;
struct mutex lock;
unsigned long flags;
unsigned int usecnt;
struct hsi_client *cl;
struct hsc_channel channels[HSC_DEVS];
};
/* Stores the major number dynamically allocated for hsi_char */
static unsigned int hsc_major;
/* Maximum buffer size that hsi_char will accept from userspace */
static unsigned int max_data_size = 0x1000;
module_param(max_data_size, uint, 0);
MODULE_PARM_DESC(max_data_size, "max read/write data size [4,8..65536] (^2)");
static void hsc_add_tail(struct hsc_channel *channel, struct hsi_msg *msg,
struct list_head *queue)
{
unsigned long flags;
spin_lock_irqsave(&channel->lock, flags);
list_add_tail(&msg->link, queue);
spin_unlock_irqrestore(&channel->lock, flags);
}
static struct hsi_msg *hsc_get_first_msg(struct hsc_channel *channel,
struct list_head *queue)
{
struct hsi_msg *msg = NULL;
unsigned long flags;
spin_lock_irqsave(&channel->lock, flags);
if (list_empty(queue))
goto out;
msg = list_first_entry(queue, struct hsi_msg, link);
list_del(&msg->link);
out:
spin_unlock_irqrestore(&channel->lock, flags);
return msg;
}
static inline void hsc_msg_free(struct hsi_msg *msg)
{
kfree(sg_virt(msg->sgt.sgl));
hsi_free_msg(msg);
}
static void hsc_free_list(struct list_head *list)
{
struct hsi_msg *msg, *tmp;
list_for_each_entry_safe(msg, tmp, list, link) {
list_del(&msg->link);
hsc_msg_free(msg);
}
}
static void hsc_reset_list(struct hsc_channel *channel, struct list_head *l)
{
unsigned long flags;
LIST_HEAD(list);
spin_lock_irqsave(&channel->lock, flags);
list_splice_init(l, &list);
spin_unlock_irqrestore(&channel->lock, flags);
hsc_free_list(&list);
}
static inline struct hsi_msg *hsc_msg_alloc(unsigned int alloc_size)
{
struct hsi_msg *msg;
void *buf;
msg = hsi_alloc_msg(1, GFP_KERNEL);
if (!msg)
goto out;
buf = kmalloc(alloc_size, GFP_KERNEL);
if (!buf) {
hsi_free_msg(msg);
goto out;
}
sg_init_one(msg->sgt.sgl, buf, alloc_size);
/* Ignore false positive, due to sg pointer handling */
kmemleak_ignore(buf);
return msg;
out:
return NULL;
}
static inline int hsc_msgs_alloc(struct hsc_channel *channel)
{
struct hsi_msg *msg;
int i;
for (i = 0; i < HSC_MSGS; i++) {
msg = hsc_msg_alloc(max_data_size);
if (!msg)
goto out;
msg->channel = channel->ch;
list_add_tail(&msg->link, &channel->free_msgs_list);
}
return 0;
out:
hsc_free_list(&channel->free_msgs_list);
return -ENOMEM;
}
static inline unsigned int hsc_msg_len_get(struct hsi_msg *msg)
{
return msg->sgt.sgl->length;
}
static inline void hsc_msg_len_set(struct hsi_msg *msg, unsigned int len)
{
msg->sgt.sgl->length = len;
}
static void hsc_rx_completed(struct hsi_msg *msg)
{
struct hsc_client_data *cl_data = hsi_client_drvdata(msg->cl);
struct hsc_channel *channel = cl_data->channels + msg->channel;
if (test_bit(HSC_CH_READ, &channel->flags)) {
hsc_add_tail(channel, msg, &channel->rx_msgs_queue);
wake_up(&channel->rx_wait);
} else {
hsc_add_tail(channel, msg, &channel->free_msgs_list);
}
}
static void hsc_rx_msg_destructor(struct hsi_msg *msg)
{
msg->status = HSI_STATUS_ERROR;
hsc_msg_len_set(msg, 0);
hsc_rx_completed(msg);
}
static void hsc_tx_completed(struct hsi_msg *msg)
{
struct hsc_client_data *cl_data = hsi_client_drvdata(msg->cl);
struct hsc_channel *channel = cl_data->channels + msg->channel;
if (test_bit(HSC_CH_WRITE, &channel->flags)) {
hsc_add_tail(channel, msg, &channel->tx_msgs_queue);
wake_up(&channel->tx_wait);
} else {
hsc_add_tail(channel, msg, &channel->free_msgs_list);
}
}
static void hsc_tx_msg_destructor(struct hsi_msg *msg)
{
msg->status = HSI_STATUS_ERROR;
hsc_msg_len_set(msg, 0);
hsc_tx_completed(msg);
}
static void hsc_break_req_destructor(struct hsi_msg *msg)
{
struct hsc_client_data *cl_data = hsi_client_drvdata(msg->cl);
hsi_free_msg(msg);
clear_bit(HSC_RXBREAK, &cl_data->flags);
}
static void hsc_break_received(struct hsi_msg *msg)
{
struct hsc_client_data *cl_data = hsi_client_drvdata(msg->cl);
struct hsc_channel *channel = cl_data->channels;
int i, ret;
/* Broadcast HWBREAK on all channels */
for (i = 0; i < HSC_DEVS; i++, channel++) {
struct hsi_msg *msg2;
if (!test_bit(HSC_CH_READ, &channel->flags))
continue;
msg2 = hsc_get_first_msg(channel, &channel->free_msgs_list);
if (!msg2)
continue;
clear_bit(HSC_CH_READ, &channel->flags);
hsc_msg_len_set(msg2, 0);
msg2->status = HSI_STATUS_COMPLETED;
hsc_add_tail(channel, msg2, &channel->rx_msgs_queue);
wake_up(&channel->rx_wait);
}
hsi_flush(msg->cl);
ret = hsi_async_read(msg->cl, msg);
if (ret < 0)
hsc_break_req_destructor(msg);
}
static int hsc_break_request(struct hsi_client *cl)
{
struct hsc_client_data *cl_data = hsi_client_drvdata(cl);
struct hsi_msg *msg;
int ret;
if (test_and_set_bit(HSC_RXBREAK, &cl_data->flags))
return -EBUSY;
msg = hsi_alloc_msg(0, GFP_KERNEL);
if (!msg) {
clear_bit(HSC_RXBREAK, &cl_data->flags);
return -ENOMEM;
}
msg->break_frame = 1;
msg->complete = hsc_break_received;
msg->destructor = hsc_break_req_destructor;
ret = hsi_async_read(cl, msg);
if (ret < 0)
hsc_break_req_destructor(msg);
return ret;
}
static int hsc_break_send(struct hsi_client *cl)
{
struct hsi_msg *msg;
int ret;
msg = hsi_alloc_msg(0, GFP_ATOMIC);
if (!msg)
return -ENOMEM;
msg->break_frame = 1;
msg->complete = hsi_free_msg;
msg->destructor = hsi_free_msg;
ret = hsi_async_write(cl, msg);
if (ret < 0)
hsi_free_msg(msg);
return ret;
}
static int hsc_rx_set(struct hsi_client *cl, struct hsc_rx_config *rxc)
{
struct hsi_config tmp;
int ret;
if ((rxc->mode != HSI_MODE_STREAM) && (rxc->mode != HSI_MODE_FRAME))
return -EINVAL;
if ((rxc->channels == 0) || (rxc->channels > HSC_DEVS))
return -EINVAL;
if (rxc->channels & (rxc->channels - 1))
return -EINVAL;
if ((rxc->flow != HSI_FLOW_SYNC) && (rxc->flow != HSI_FLOW_PIPE))
return -EINVAL;
tmp = cl->rx_cfg;
cl->rx_cfg.mode = rxc->mode;
cl->rx_cfg.num_hw_channels = rxc->channels;
cl->rx_cfg.flow = rxc->flow;
ret = hsi_setup(cl);
if (ret < 0) {
cl->rx_cfg = tmp;
return ret;
}
if (rxc->mode == HSI_MODE_FRAME)
hsc_break_request(cl);
return ret;
}
static inline void hsc_rx_get(struct hsi_client *cl, struct hsc_rx_config *rxc)
{
rxc->mode = cl->rx_cfg.mode;
rxc->channels = cl->rx_cfg.num_hw_channels;
rxc->flow = cl->rx_cfg.flow;
}
static int hsc_tx_set(struct hsi_client *cl, struct hsc_tx_config *txc)
{
struct hsi_config tmp;
int ret;
if ((txc->mode != HSI_MODE_STREAM) && (txc->mode != HSI_MODE_FRAME))
return -EINVAL;
if ((txc->channels == 0) || (txc->channels > HSC_DEVS))
return -EINVAL;
if (txc->channels & (txc->channels - 1))
return -EINVAL;
if ((txc->arb_mode != HSI_ARB_RR) && (txc->arb_mode != HSI_ARB_PRIO))
return -EINVAL;
tmp = cl->tx_cfg;
cl->tx_cfg.mode = txc->mode;
cl->tx_cfg.num_hw_channels = txc->channels;
cl->tx_cfg.speed = txc->speed;
cl->tx_cfg.arb_mode = txc->arb_mode;
ret = hsi_setup(cl);
if (ret < 0) {
cl->tx_cfg = tmp;
return ret;
}
return ret;
}
static inline void hsc_tx_get(struct hsi_client *cl, struct hsc_tx_config *txc)
{
txc->mode = cl->tx_cfg.mode;
txc->channels = cl->tx_cfg.num_hw_channels;
txc->speed = cl->tx_cfg.speed;
txc->arb_mode = cl->tx_cfg.arb_mode;
}
static ssize_t hsc_read(struct file *file, char __user *buf, size_t len,
loff_t *ppos __maybe_unused)
{
struct hsc_channel *channel = file->private_data;
struct hsi_msg *msg;
ssize_t ret;
if (len == 0)
return 0;
if (!IS_ALIGNED(len, sizeof(u32)))
return -EINVAL;
if (len > max_data_size)
len = max_data_size;
if (channel->ch >= channel->cl->rx_cfg.num_hw_channels)
return -ECHRNG;
if (test_and_set_bit(HSC_CH_READ, &channel->flags))
return -EBUSY;
msg = hsc_get_first_msg(channel, &channel->free_msgs_list);
if (!msg) {
ret = -ENOSPC;
goto out;
}
hsc_msg_len_set(msg, len);
msg->complete = hsc_rx_completed;
msg->destructor = hsc_rx_msg_destructor;
ret = hsi_async_read(channel->cl, msg);
if (ret < 0) {
hsc_add_tail(channel, msg, &channel->free_msgs_list);
goto out;
}
ret = wait_event_interruptible(channel->rx_wait,
!list_empty(&channel->rx_msgs_queue));
if (ret < 0) {
clear_bit(HSC_CH_READ, &channel->flags);
hsi_flush(channel->cl);
return -EINTR;
}
msg = hsc_get_first_msg(channel, &channel->rx_msgs_queue);
if (msg) {
if (msg->status != HSI_STATUS_ERROR) {
ret = copy_to_user((void __user *)buf,
sg_virt(msg->sgt.sgl), hsc_msg_len_get(msg));
if (ret)
ret = -EFAULT;
else
ret = hsc_msg_len_get(msg);
} else {
ret = -EIO;
}
hsc_add_tail(channel, msg, &channel->free_msgs_list);
}
out:
clear_bit(HSC_CH_READ, &channel->flags);
return ret;
}
static ssize_t hsc_write(struct file *file, const char __user *buf, size_t len,
loff_t *ppos __maybe_unused)
{
struct hsc_channel *channel = file->private_data;
struct hsi_msg *msg;
ssize_t ret;
if ((len == 0) || !IS_ALIGNED(len, sizeof(u32)))
return -EINVAL;
if (len > max_data_size)
len = max_data_size;
if (channel->ch >= channel->cl->tx_cfg.num_hw_channels)
return -ECHRNG;
if (test_and_set_bit(HSC_CH_WRITE, &channel->flags))
return -EBUSY;
msg = hsc_get_first_msg(channel, &channel->free_msgs_list);
if (!msg) {
clear_bit(HSC_CH_WRITE, &channel->flags);
return -ENOSPC;
}
if (copy_from_user(sg_virt(msg->sgt.sgl), (void __user *)buf, len)) {
ret = -EFAULT;
goto out;
}
hsc_msg_len_set(msg, len);
msg->complete = hsc_tx_completed;
msg->destructor = hsc_tx_msg_destructor;
ret = hsi_async_write(channel->cl, msg);
if (ret < 0)
goto out;
ret = wait_event_interruptible(channel->tx_wait,
!list_empty(&channel->tx_msgs_queue));
if (ret < 0) {
clear_bit(HSC_CH_WRITE, &channel->flags);
hsi_flush(channel->cl);
return -EINTR;
}
msg = hsc_get_first_msg(channel, &channel->tx_msgs_queue);
if (msg) {
if (msg->status == HSI_STATUS_ERROR)
ret = -EIO;
else
ret = hsc_msg_len_get(msg);
hsc_add_tail(channel, msg, &channel->free_msgs_list);
}
out:
clear_bit(HSC_CH_WRITE, &channel->flags);
return ret;
}
static long hsc_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
{
struct hsc_channel *channel = file->private_data;
unsigned int state;
struct hsc_rx_config rxc;
struct hsc_tx_config txc;
long ret = 0;
switch (cmd) {
case HSC_RESET:
hsi_flush(channel->cl);
break;
case HSC_SET_PM:
if (copy_from_user(&state, (void __user *)arg, sizeof(state)))
return -EFAULT;
if (state == HSC_PM_DISABLE) {
if (test_and_set_bit(HSC_CH_WLINE, &channel->flags))
return -EINVAL;
ret = hsi_start_tx(channel->cl);
} else if (state == HSC_PM_ENABLE) {
if (!test_and_clear_bit(HSC_CH_WLINE, &channel->flags))
return -EINVAL;
ret = hsi_stop_tx(channel->cl);
} else {
ret = -EINVAL;
}
break;
case HSC_SEND_BREAK:
return hsc_break_send(channel->cl);
case HSC_SET_RX:
if (copy_from_user(&rxc, (void __user *)arg, sizeof(rxc)))
return -EFAULT;
return hsc_rx_set(channel->cl, &rxc);
case HSC_GET_RX:
hsc_rx_get(channel->cl, &rxc);
if (copy_to_user((void __user *)arg, &rxc, sizeof(rxc)))
return -EFAULT;
break;
case HSC_SET_TX:
if (copy_from_user(&txc, (void __user *)arg, sizeof(txc)))
return -EFAULT;
return hsc_tx_set(channel->cl, &txc);
case HSC_GET_TX:
hsc_tx_get(channel->cl, &txc);
if (copy_to_user((void __user *)arg, &txc, sizeof(txc)))
return -EFAULT;
break;
default:
return -ENOIOCTLCMD;
}
return ret;
}
static inline void __hsc_port_release(struct hsc_client_data *cl_data)
{
BUG_ON(cl_data->usecnt == 0);
if (--cl_data->usecnt == 0) {
hsi_flush(cl_data->cl);
hsi_release_port(cl_data->cl);
}
}
static int hsc_open(struct inode *inode, struct file *file)
{
struct hsc_client_data *cl_data;
struct hsc_channel *channel;
int ret = 0;
pr_debug("open, minor = %d\n", iminor(inode));
cl_data = container_of(inode->i_cdev, struct hsc_client_data, cdev);
mutex_lock(&cl_data->lock);
channel = cl_data->channels + (iminor(inode) & HSC_CH_MASK);
if (test_and_set_bit(HSC_CH_OPEN, &channel->flags)) {
ret = -EBUSY;
goto out;
}
/*
* Check if we have already claimed the port associated to the HSI
* client. If not then try to claim it, else increase its refcount
*/
if (cl_data->usecnt == 0) {
ret = hsi_claim_port(cl_data->cl, 0);
if (ret < 0)
goto out;
hsi_setup(cl_data->cl);
}
cl_data->usecnt++;
ret = hsc_msgs_alloc(channel);
if (ret < 0) {
__hsc_port_release(cl_data);
goto out;
}
file->private_data = channel;
mutex_unlock(&cl_data->lock);
return ret;
out:
mutex_unlock(&cl_data->lock);
return ret;
}
static int hsc_release(struct inode *inode __maybe_unused, struct file *file)
{
struct hsc_channel *channel = file->private_data;
struct hsc_client_data *cl_data = channel->cl_data;
mutex_lock(&cl_data->lock);
file->private_data = NULL;
if (test_and_clear_bit(HSC_CH_WLINE, &channel->flags))
hsi_stop_tx(channel->cl);
__hsc_port_release(cl_data);
hsc_reset_list(channel, &channel->rx_msgs_queue);
hsc_reset_list(channel, &channel->tx_msgs_queue);
hsc_reset_list(channel, &channel->free_msgs_list);
clear_bit(HSC_CH_READ, &channel->flags);
clear_bit(HSC_CH_WRITE, &channel->flags);
clear_bit(HSC_CH_OPEN, &channel->flags);
wake_up(&channel->rx_wait);
wake_up(&channel->tx_wait);
mutex_unlock(&cl_data->lock);
return 0;
}
static const struct file_operations hsc_fops = {
.owner = THIS_MODULE,
.read = hsc_read,
.write = hsc_write,
.unlocked_ioctl = hsc_ioctl,
.open = hsc_open,
.release = hsc_release,
};
static void hsc_channel_init(struct hsc_channel *channel)
{
init_waitqueue_head(&channel->rx_wait);
init_waitqueue_head(&channel->tx_wait);
spin_lock_init(&channel->lock);
INIT_LIST_HEAD(&channel->free_msgs_list);
INIT_LIST_HEAD(&channel->rx_msgs_queue);
INIT_LIST_HEAD(&channel->tx_msgs_queue);
}
static int hsc_probe(struct device *dev)
{
const char devname[] = "hsi_char";
struct hsc_client_data *cl_data;
struct hsc_channel *channel;
struct hsi_client *cl = to_hsi_client(dev);
unsigned int hsc_baseminor;
dev_t hsc_dev;
int ret;
int i;
cl_data = kzalloc(sizeof(*cl_data), GFP_KERNEL);
if (!cl_data)
return -ENOMEM;
hsc_baseminor = HSC_BASEMINOR(hsi_id(cl), hsi_port_id(cl));
if (!hsc_major) {
ret = alloc_chrdev_region(&hsc_dev, hsc_baseminor,
HSC_DEVS, devname);
if (ret == 0)
hsc_major = MAJOR(hsc_dev);
} else {
hsc_dev = MKDEV(hsc_major, hsc_baseminor);
ret = register_chrdev_region(hsc_dev, HSC_DEVS, devname);
}
if (ret < 0) {
dev_err(dev, "Device %s allocation failed %d\n",
hsc_major ? "minor" : "major", ret);
goto out1;
}
mutex_init(&cl_data->lock);
hsi_client_set_drvdata(cl, cl_data);
cdev_init(&cl_data->cdev, &hsc_fops);
cl_data->cdev.owner = THIS_MODULE;
cl_data->cl = cl;
for (i = 0, channel = cl_data->channels; i < HSC_DEVS; i++, channel++) {
hsc_channel_init(channel);
channel->ch = i;
channel->cl = cl;
channel->cl_data = cl_data;
}
/* 1 hsi client -> N char devices (one for each channel) */
ret = cdev_add(&cl_data->cdev, hsc_dev, HSC_DEVS);
if (ret) {
dev_err(dev, "Could not add char device %d\n", ret);
goto out2;
}
return 0;
out2:
unregister_chrdev_region(hsc_dev, HSC_DEVS);
out1:
kfree(cl_data);
return ret;
}
static int hsc_remove(struct device *dev)
{
struct hsi_client *cl = to_hsi_client(dev);
struct hsc_client_data *cl_data = hsi_client_drvdata(cl);
dev_t hsc_dev = cl_data->cdev.dev;
cdev_del(&cl_data->cdev);
unregister_chrdev_region(hsc_dev, HSC_DEVS);
hsi_client_set_drvdata(cl, NULL);
kfree(cl_data);
return 0;
}
static struct hsi_client_driver hsc_driver = {
.driver = {
.name = "hsi_char",
.owner = THIS_MODULE,
.probe = hsc_probe,
.remove = hsc_remove,
},
};
static int __init hsc_init(void)
{
int ret;
if ((max_data_size < 4) || (max_data_size > 0x10000) ||
(max_data_size & (max_data_size - 1))) {
pr_err("Invalid max read/write data size\n");
return -EINVAL;
}
ret = hsi_register_client_driver(&hsc_driver);
if (ret) {
pr_err("Error while registering HSI/SSI driver %d\n", ret);
return ret;
}
pr_info("HSI/SSI char device loaded\n");
return 0;
}
module_init(hsc_init);
static void __exit hsc_exit(void)
{
hsi_unregister_client_driver(&hsc_driver);
pr_info("HSI char device removed\n");
}
module_exit(hsc_exit);
MODULE_AUTHOR("Andras Domokos <[email protected]>");
MODULE_ALIAS("hsi:hsi_char");
MODULE_DESCRIPTION("HSI character device");
MODULE_LICENSE("GPL v2");
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