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|
// SPDX-License-Identifier: GPL-2.0
/*
* core.c - Implementation of core module of MOST Linux driver stack
*
* Copyright (C) 2013-2015 Microchip Technology Germany II GmbH & Co. KG
*/
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
#include <linux/module.h>
#include <linux/fs.h>
#include <linux/slab.h>
#include <linux/init.h>
#include <linux/device.h>
#include <linux/list.h>
#include <linux/poll.h>
#include <linux/wait.h>
#include <linux/kobject.h>
#include <linux/mutex.h>
#include <linux/completion.h>
#include <linux/sysfs.h>
#include <linux/kthread.h>
#include <linux/dma-mapping.h>
#include <linux/idr.h>
#include <most/core.h>
#define MAX_CHANNELS 64
#define STRING_SIZE 80
static struct ida mdev_id;
static int dummy_num_buffers;
static struct mostcore {
struct device dev;
struct device_driver drv;
struct bus_type bus;
struct class *class;
struct list_head comp_list;
} mc;
#define to_driver(d) container_of(d, struct mostcore, drv);
struct pipe {
struct core_component *aim;
int refs;
int num_buffers;
};
struct most_channel {
struct device dev;
struct completion cleanup;
atomic_t mbo_ref;
atomic_t mbo_nq_level;
u16 channel_id;
char name[STRING_SIZE];
bool is_poisoned;
struct mutex start_mutex;
struct mutex nq_mutex; /* nq thread synchronization */
int is_starving;
struct most_interface *iface;
struct most_channel_config cfg;
bool keep_mbo;
bool enqueue_halt;
struct list_head fifo;
spinlock_t fifo_lock;
struct list_head halt_fifo;
struct list_head list;
struct pipe pipe0;
struct pipe pipe1;
struct list_head trash_fifo;
struct task_struct *hdm_enqueue_task;
wait_queue_head_t hdm_fifo_wq;
};
#define to_channel(d) container_of(d, struct most_channel, dev)
struct interface_private {
int dev_id;
char name[STRING_SIZE];
struct most_channel *channel[MAX_CHANNELS];
struct list_head channel_list;
};
static const struct {
int most_ch_data_type;
const char *name;
} ch_data_type[] = {
{ MOST_CH_CONTROL, "control\n" },
{ MOST_CH_ASYNC, "async\n" },
{ MOST_CH_SYNC, "sync\n" },
{ MOST_CH_ISOC, "isoc\n"},
{ MOST_CH_ISOC, "isoc_avp\n"},
};
/**
* list_pop_mbo - retrieves the first MBO of the list and removes it
* @ptr: the list head to grab the MBO from.
*/
#define list_pop_mbo(ptr) \
({ \
struct mbo *_mbo = list_first_entry(ptr, struct mbo, list); \
list_del(&_mbo->list); \
_mbo; \
})
/* ___ ___
* ___C H A N N E L___
*/
/**
* most_free_mbo_coherent - free an MBO and its coherent buffer
* @mbo: buffer to be released
*
*/
static void most_free_mbo_coherent(struct mbo *mbo)
{
struct most_channel *c = mbo->context;
u16 const coherent_buf_size = c->cfg.buffer_size + c->cfg.extra_len;
dma_free_coherent(NULL, coherent_buf_size, mbo->virt_address,
mbo->bus_address);
kfree(mbo);
if (atomic_sub_and_test(1, &c->mbo_ref))
complete(&c->cleanup);
}
/**
* flush_channel_fifos - clear the channel fifos
* @c: pointer to channel object
*/
static void flush_channel_fifos(struct most_channel *c)
{
unsigned long flags, hf_flags;
struct mbo *mbo, *tmp;
if (list_empty(&c->fifo) && list_empty(&c->halt_fifo))
return;
spin_lock_irqsave(&c->fifo_lock, flags);
list_for_each_entry_safe(mbo, tmp, &c->fifo, list) {
list_del(&mbo->list);
spin_unlock_irqrestore(&c->fifo_lock, flags);
most_free_mbo_coherent(mbo);
spin_lock_irqsave(&c->fifo_lock, flags);
}
spin_unlock_irqrestore(&c->fifo_lock, flags);
spin_lock_irqsave(&c->fifo_lock, hf_flags);
list_for_each_entry_safe(mbo, tmp, &c->halt_fifo, list) {
list_del(&mbo->list);
spin_unlock_irqrestore(&c->fifo_lock, hf_flags);
most_free_mbo_coherent(mbo);
spin_lock_irqsave(&c->fifo_lock, hf_flags);
}
spin_unlock_irqrestore(&c->fifo_lock, hf_flags);
if (unlikely((!list_empty(&c->fifo) || !list_empty(&c->halt_fifo))))
pr_info("WARN: fifo | trash fifo not empty\n");
}
/**
* flush_trash_fifo - clear the trash fifo
* @c: pointer to channel object
*/
static int flush_trash_fifo(struct most_channel *c)
{
struct mbo *mbo, *tmp;
unsigned long flags;
spin_lock_irqsave(&c->fifo_lock, flags);
list_for_each_entry_safe(mbo, tmp, &c->trash_fifo, list) {
list_del(&mbo->list);
spin_unlock_irqrestore(&c->fifo_lock, flags);
most_free_mbo_coherent(mbo);
spin_lock_irqsave(&c->fifo_lock, flags);
}
spin_unlock_irqrestore(&c->fifo_lock, flags);
return 0;
}
static ssize_t available_directions_show(struct device *dev,
struct device_attribute *attr,
char *buf)
{
struct most_channel *c = to_channel(dev);
unsigned int i = c->channel_id;
strcpy(buf, "");
if (c->iface->channel_vector[i].direction & MOST_CH_RX)
strcat(buf, "rx ");
if (c->iface->channel_vector[i].direction & MOST_CH_TX)
strcat(buf, "tx ");
strcat(buf, "\n");
return strlen(buf);
}
static ssize_t available_datatypes_show(struct device *dev,
struct device_attribute *attr,
char *buf)
{
struct most_channel *c = to_channel(dev);
unsigned int i = c->channel_id;
strcpy(buf, "");
if (c->iface->channel_vector[i].data_type & MOST_CH_CONTROL)
strcat(buf, "control ");
if (c->iface->channel_vector[i].data_type & MOST_CH_ASYNC)
strcat(buf, "async ");
if (c->iface->channel_vector[i].data_type & MOST_CH_SYNC)
strcat(buf, "sync ");
if (c->iface->channel_vector[i].data_type & MOST_CH_ISOC)
strcat(buf, "isoc ");
strcat(buf, "\n");
return strlen(buf);
}
static ssize_t number_of_packet_buffers_show(struct device *dev,
struct device_attribute *attr,
char *buf)
{
struct most_channel *c = to_channel(dev);
unsigned int i = c->channel_id;
return snprintf(buf, PAGE_SIZE, "%d\n",
c->iface->channel_vector[i].num_buffers_packet);
}
static ssize_t number_of_stream_buffers_show(struct device *dev,
struct device_attribute *attr,
char *buf)
{
struct most_channel *c = to_channel(dev);
unsigned int i = c->channel_id;
return snprintf(buf, PAGE_SIZE, "%d\n",
c->iface->channel_vector[i].num_buffers_streaming);
}
static ssize_t size_of_packet_buffer_show(struct device *dev,
struct device_attribute *attr,
char *buf)
{
struct most_channel *c = to_channel(dev);
unsigned int i = c->channel_id;
return snprintf(buf, PAGE_SIZE, "%d\n",
c->iface->channel_vector[i].buffer_size_packet);
}
static ssize_t size_of_stream_buffer_show(struct device *dev,
struct device_attribute *attr,
char *buf)
{
struct most_channel *c = to_channel(dev);
unsigned int i = c->channel_id;
return snprintf(buf, PAGE_SIZE, "%d\n",
c->iface->channel_vector[i].buffer_size_streaming);
}
static ssize_t channel_starving_show(struct device *dev,
struct device_attribute *attr,
char *buf)
{
struct most_channel *c = to_channel(dev);
return snprintf(buf, PAGE_SIZE, "%d\n", c->is_starving);
}
static ssize_t set_number_of_buffers_show(struct device *dev,
struct device_attribute *attr,
char *buf)
{
struct most_channel *c = to_channel(dev);
return snprintf(buf, PAGE_SIZE, "%d\n", c->cfg.num_buffers);
}
static ssize_t set_number_of_buffers_store(struct device *dev,
struct device_attribute *attr,
const char *buf,
size_t count)
{
struct most_channel *c = to_channel(dev);
int ret = kstrtou16(buf, 0, &c->cfg.num_buffers);
if (ret)
return ret;
return count;
}
static ssize_t set_buffer_size_show(struct device *dev,
struct device_attribute *attr,
char *buf)
{
struct most_channel *c = to_channel(dev);
return snprintf(buf, PAGE_SIZE, "%d\n", c->cfg.buffer_size);
}
static ssize_t set_buffer_size_store(struct device *dev,
struct device_attribute *attr,
const char *buf,
size_t count)
{
struct most_channel *c = to_channel(dev);
int ret = kstrtou16(buf, 0, &c->cfg.buffer_size);
if (ret)
return ret;
return count;
}
static ssize_t set_direction_show(struct device *dev,
struct device_attribute *attr,
char *buf)
{
struct most_channel *c = to_channel(dev);
if (c->cfg.direction & MOST_CH_TX)
return snprintf(buf, PAGE_SIZE, "tx\n");
else if (c->cfg.direction & MOST_CH_RX)
return snprintf(buf, PAGE_SIZE, "rx\n");
return snprintf(buf, PAGE_SIZE, "unconfigured\n");
}
static ssize_t set_direction_store(struct device *dev,
struct device_attribute *attr,
const char *buf,
size_t count)
{
struct most_channel *c = to_channel(dev);
if (!strcmp(buf, "dir_rx\n")) {
c->cfg.direction = MOST_CH_RX;
} else if (!strcmp(buf, "rx\n")) {
c->cfg.direction = MOST_CH_RX;
} else if (!strcmp(buf, "dir_tx\n")) {
c->cfg.direction = MOST_CH_TX;
} else if (!strcmp(buf, "tx\n")) {
c->cfg.direction = MOST_CH_TX;
} else {
pr_info("WARN: invalid attribute settings\n");
return -EINVAL;
}
return count;
}
static ssize_t set_datatype_show(struct device *dev,
struct device_attribute *attr,
char *buf)
{
int i;
struct most_channel *c = to_channel(dev);
for (i = 0; i < ARRAY_SIZE(ch_data_type); i++) {
if (c->cfg.data_type & ch_data_type[i].most_ch_data_type)
return snprintf(buf, PAGE_SIZE, ch_data_type[i].name);
}
return snprintf(buf, PAGE_SIZE, "unconfigured\n");
}
static ssize_t set_datatype_store(struct device *dev,
struct device_attribute *attr,
const char *buf,
size_t count)
{
int i;
struct most_channel *c = to_channel(dev);
for (i = 0; i < ARRAY_SIZE(ch_data_type); i++) {
if (!strcmp(buf, ch_data_type[i].name)) {
c->cfg.data_type = ch_data_type[i].most_ch_data_type;
break;
}
}
if (i == ARRAY_SIZE(ch_data_type)) {
pr_info("WARN: invalid attribute settings\n");
return -EINVAL;
}
return count;
}
static ssize_t set_subbuffer_size_show(struct device *dev,
struct device_attribute *attr,
char *buf)
{
struct most_channel *c = to_channel(dev);
return snprintf(buf, PAGE_SIZE, "%d\n", c->cfg.subbuffer_size);
}
static ssize_t set_subbuffer_size_store(struct device *dev,
struct device_attribute *attr,
const char *buf,
size_t count)
{
struct most_channel *c = to_channel(dev);
int ret = kstrtou16(buf, 0, &c->cfg.subbuffer_size);
if (ret)
return ret;
return count;
}
static ssize_t set_packets_per_xact_show(struct device *dev,
struct device_attribute *attr,
char *buf)
{
struct most_channel *c = to_channel(dev);
return snprintf(buf, PAGE_SIZE, "%d\n", c->cfg.packets_per_xact);
}
static ssize_t set_packets_per_xact_store(struct device *dev,
struct device_attribute *attr,
const char *buf,
size_t count)
{
struct most_channel *c = to_channel(dev);
int ret = kstrtou16(buf, 0, &c->cfg.packets_per_xact);
if (ret)
return ret;
return count;
}
#define DEV_ATTR(_name) (&dev_attr_##_name.attr)
static DEVICE_ATTR_RO(available_directions);
static DEVICE_ATTR_RO(available_datatypes);
static DEVICE_ATTR_RO(number_of_packet_buffers);
static DEVICE_ATTR_RO(number_of_stream_buffers);
static DEVICE_ATTR_RO(size_of_stream_buffer);
static DEVICE_ATTR_RO(size_of_packet_buffer);
static DEVICE_ATTR_RO(channel_starving);
static DEVICE_ATTR_RW(set_buffer_size);
static DEVICE_ATTR_RW(set_number_of_buffers);
static DEVICE_ATTR_RW(set_direction);
static DEVICE_ATTR_RW(set_datatype);
static DEVICE_ATTR_RW(set_subbuffer_size);
static DEVICE_ATTR_RW(set_packets_per_xact);
static struct attribute *channel_attrs[] = {
DEV_ATTR(available_directions),
DEV_ATTR(available_datatypes),
DEV_ATTR(number_of_packet_buffers),
DEV_ATTR(number_of_stream_buffers),
DEV_ATTR(size_of_stream_buffer),
DEV_ATTR(size_of_packet_buffer),
DEV_ATTR(channel_starving),
DEV_ATTR(set_buffer_size),
DEV_ATTR(set_number_of_buffers),
DEV_ATTR(set_direction),
DEV_ATTR(set_datatype),
DEV_ATTR(set_subbuffer_size),
DEV_ATTR(set_packets_per_xact),
NULL,
};
static struct attribute_group channel_attr_group = {
.attrs = channel_attrs,
};
static const struct attribute_group *channel_attr_groups[] = {
&channel_attr_group,
NULL,
};
/* ___ ___
* ___I N S T A N C E___
*/
static ssize_t description_show(struct device *dev,
struct device_attribute *attr,
char *buf)
{
struct most_interface *iface = to_most_interface(dev);
return snprintf(buf, PAGE_SIZE, "%s\n", iface->description);
}
static ssize_t interface_show(struct device *dev,
struct device_attribute *attr,
char *buf)
{
struct most_interface *iface = to_most_interface(dev);
switch (iface->interface) {
case ITYPE_LOOPBACK:
return snprintf(buf, PAGE_SIZE, "loopback\n");
case ITYPE_I2C:
return snprintf(buf, PAGE_SIZE, "i2c\n");
case ITYPE_I2S:
return snprintf(buf, PAGE_SIZE, "i2s\n");
case ITYPE_TSI:
return snprintf(buf, PAGE_SIZE, "tsi\n");
case ITYPE_HBI:
return snprintf(buf, PAGE_SIZE, "hbi\n");
case ITYPE_MEDIALB_DIM:
return snprintf(buf, PAGE_SIZE, "mlb_dim\n");
case ITYPE_MEDIALB_DIM2:
return snprintf(buf, PAGE_SIZE, "mlb_dim2\n");
case ITYPE_USB:
return snprintf(buf, PAGE_SIZE, "usb\n");
case ITYPE_PCIE:
return snprintf(buf, PAGE_SIZE, "pcie\n");
}
return snprintf(buf, PAGE_SIZE, "unknown\n");
}
static DEVICE_ATTR_RO(description);
static DEVICE_ATTR_RO(interface);
static struct attribute *interface_attrs[] = {
DEV_ATTR(description),
DEV_ATTR(interface),
NULL,
};
static struct attribute_group interface_attr_group = {
.attrs = interface_attrs,
};
static const struct attribute_group *interface_attr_groups[] = {
&interface_attr_group,
NULL,
};
/* ___ ___
* ___A I M___
*/
static struct core_component *match_module(char *name)
{
struct core_component *aim;
list_for_each_entry(aim, &mc.comp_list, list) {
if (!strcmp(aim->name, name))
return aim;
}
return NULL;
}
int print_links(struct device *dev, void *data)
{
int offs = 0;
char *buf = data;
struct most_channel *c;
struct most_interface *iface = to_most_interface(dev);
list_for_each_entry(c, &iface->p->channel_list, list) {
if (c->pipe0.aim) {
offs += snprintf(buf + offs,
PAGE_SIZE - offs,
"%s:%s:%s\n",
c->pipe0.aim->name,
dev_name(&iface->dev),
dev_name(&c->dev));
}
if (c->pipe1.aim) {
offs += snprintf(buf + offs,
PAGE_SIZE - offs,
"%s:%s:%s\n",
c->pipe1.aim->name,
dev_name(&iface->dev),
dev_name(&c->dev));
}
}
return 0;
}
static ssize_t links_show(struct device_driver *drv, char *buf)
{
bus_for_each_dev(&mc.bus, NULL, buf, print_links);
return strlen(buf);
}
static ssize_t modules_show(struct device_driver *drv, char *buf)
{
struct core_component *aim;
int offs = 0;
list_for_each_entry(aim, &mc.comp_list, list) {
offs += snprintf(buf + offs, PAGE_SIZE - offs, "%s\n",
aim->name);
}
return offs;
}
/**
* split_string - parses and changes string in the buffer buf and
* splits it into two mandatory and one optional substrings.
*
* @buf: complete string from attribute 'add_channel'
* @a: address of pointer to 1st substring (=instance name)
* @b: address of pointer to 2nd substring (=channel name)
* @c: optional address of pointer to 3rd substring (=user defined name)
*
* Examples:
*
* Input: "mdev0:ch6:my_channel\n" or
* "mdev0:ch6:my_channel"
*
* Output: *a -> "mdev0", *b -> "ch6", *c -> "my_channel"
*
* Input: "mdev1:ep81\n"
* Output: *a -> "mdev1", *b -> "ep81", *c -> ""
*
* Input: "mdev1:ep81"
* Output: *a -> "mdev1", *b -> "ep81", *c == NULL
*/
static int split_string(char *buf, char **a, char **b, char **c, char **d)
{
*a = strsep(&buf, ":");
if (!*a)
return -EIO;
*b = strsep(&buf, ":\n");
if (!*b)
return -EIO;
*c = strsep(&buf, ":\n");
if (!*c)
return -EIO;
if (d)
*d = strsep(&buf, ":\n");
return 0;
}
static int match_bus_dev(struct device *dev, void *data)
{
char *mdev_name = data;
return !strcmp(dev_name(dev), mdev_name);
}
/**
* get_channel - get pointer to channel object
* @mdev: name of the device instance
* @mdev_ch: name of the respective channel
*
* This retrieves the pointer to a channel object.
*/
static struct most_channel *get_channel(char *mdev, char *mdev_ch)
{
struct device *dev = NULL;
struct most_interface *iface;
struct most_channel *c, *tmp;
dev = bus_find_device(&mc.bus, NULL, mdev, match_bus_dev);
if (!dev)
return NULL;
iface = to_most_interface(dev);
list_for_each_entry_safe(c, tmp, &iface->p->channel_list, list) {
if (!strcmp(dev_name(&c->dev), mdev_ch))
return c;
}
return NULL;
}
static
inline int link_channel_to_aim(struct most_channel *c, struct core_component *aim,
char *aim_param)
{
int ret;
struct core_component **aim_ptr;
if (!c->pipe0.aim)
aim_ptr = &c->pipe0.aim;
else if (!c->pipe1.aim)
aim_ptr = &c->pipe1.aim;
else
return -ENOSPC;
*aim_ptr = aim;
ret = aim->probe_channel(c->iface, c->channel_id,
&c->cfg, aim_param);
if (ret) {
*aim_ptr = NULL;
return ret;
}
return 0;
}
/**
* add_link_store - store() function for add_link attribute
* @aim_obj: pointer to AIM object
* @attr: its attributes
* @buf: buffer
* @len: buffer length
*
* This parses the string given by buf and splits it into
* three substrings. Note: third substring is optional. In case a cdev
* AIM is loaded the optional 3rd substring will make up the name of
* device node in the /dev directory. If omitted, the device node will
* inherit the channel's name within sysfs.
*
* Searches for a pair of device and channel and probes the AIM
*
* Example:
* (1) echo "mdev0:ch6:my_rxchannel" >add_link
* (2) echo "mdev1:ep81" >add_link
*
* (1) would create the device node /dev/my_rxchannel
* (2) would create the device node /dev/mdev1-ep81
*/
static ssize_t add_link_store(struct device_driver *drv,
const char *buf,
size_t len)
{
struct most_channel *c;
struct core_component *aim;
char buffer[STRING_SIZE];
char *mdev;
char *mdev_ch;
char *aim_name;
char *aim_param;
char devnod_buf[STRING_SIZE];
int ret;
size_t max_len = min_t(size_t, len + 1, STRING_SIZE);
strlcpy(buffer, buf, max_len);
ret = split_string(buffer, &mdev, &mdev_ch, &aim_name, &aim_param);
if (ret)
return ret;
aim = match_module(aim_name);
if (!aim_param || *aim_param == 0) {
snprintf(devnod_buf, sizeof(devnod_buf), "%s-%s", mdev,
mdev_ch);
aim_param = devnod_buf;
}
c = get_channel(mdev, mdev_ch);
if (!c)
return -ENODEV;
ret = link_channel_to_aim(c, aim, aim_param);
if (ret)
return ret;
return len;
}
/**
* remove_link_store - store function for remove_link attribute
* @aim_obj: pointer to AIM object
* @attr: its attributes
* @buf: buffer
* @len: buffer length
*
* Example:
* echo "mdev0:ep81" >remove_link
*/
static ssize_t remove_link_store(struct device_driver *drv,
const char *buf,
size_t len)
{
struct most_channel *c;
struct core_component *aim;
char buffer[STRING_SIZE];
char *mdev;
char *mdev_ch;
char *aim_name;
int ret;
size_t max_len = min_t(size_t, len + 1, STRING_SIZE);
strlcpy(buffer, buf, max_len);
ret = split_string(buffer, &mdev, &mdev_ch, &aim_name, NULL);
if (ret)
return ret;
aim = match_module(aim_name);
c = get_channel(mdev, mdev_ch);
if (!c)
return -ENODEV;
if (aim->disconnect_channel(c->iface, c->channel_id))
return -EIO;
if (c->pipe0.aim == aim)
c->pipe0.aim = NULL;
if (c->pipe1.aim == aim)
c->pipe1.aim = NULL;
return len;
}
#define DRV_ATTR(_name) (&driver_attr_##_name.attr)
static DRIVER_ATTR_RO(links);
static DRIVER_ATTR_RO(modules);
static DRIVER_ATTR_WO(add_link);
static DRIVER_ATTR_WO(remove_link);
static struct attribute *module_attrs[] = {
DRV_ATTR(links),
DRV_ATTR(modules),
DRV_ATTR(add_link),
DRV_ATTR(remove_link),
NULL,
};
static struct attribute_group module_attr_group = {
.attrs = module_attrs,
};
static const struct attribute_group *module_attr_groups[] = {
&module_attr_group,
NULL,
};
/* ___ ___
* ___C O R E___
*/
int most_match(struct device *dev, struct device_driver *drv)
{
if (!strcmp(dev_name(dev), "most"))
return 0;
else
return 1;
}
static inline void trash_mbo(struct mbo *mbo)
{
unsigned long flags;
struct most_channel *c = mbo->context;
spin_lock_irqsave(&c->fifo_lock, flags);
list_add(&mbo->list, &c->trash_fifo);
spin_unlock_irqrestore(&c->fifo_lock, flags);
}
static bool hdm_mbo_ready(struct most_channel *c)
{
bool empty;
if (c->enqueue_halt)
return false;
spin_lock_irq(&c->fifo_lock);
empty = list_empty(&c->halt_fifo);
spin_unlock_irq(&c->fifo_lock);
return !empty;
}
static void nq_hdm_mbo(struct mbo *mbo)
{
unsigned long flags;
struct most_channel *c = mbo->context;
spin_lock_irqsave(&c->fifo_lock, flags);
list_add_tail(&mbo->list, &c->halt_fifo);
spin_unlock_irqrestore(&c->fifo_lock, flags);
wake_up_interruptible(&c->hdm_fifo_wq);
}
static int hdm_enqueue_thread(void *data)
{
struct most_channel *c = data;
struct mbo *mbo;
int ret;
typeof(c->iface->enqueue) enqueue = c->iface->enqueue;
while (likely(!kthread_should_stop())) {
wait_event_interruptible(c->hdm_fifo_wq,
hdm_mbo_ready(c) ||
kthread_should_stop());
mutex_lock(&c->nq_mutex);
spin_lock_irq(&c->fifo_lock);
if (unlikely(c->enqueue_halt || list_empty(&c->halt_fifo))) {
spin_unlock_irq(&c->fifo_lock);
mutex_unlock(&c->nq_mutex);
continue;
}
mbo = list_pop_mbo(&c->halt_fifo);
spin_unlock_irq(&c->fifo_lock);
if (c->cfg.direction == MOST_CH_RX)
mbo->buffer_length = c->cfg.buffer_size;
ret = enqueue(mbo->ifp, mbo->hdm_channel_id, mbo);
mutex_unlock(&c->nq_mutex);
if (unlikely(ret)) {
pr_err("hdm enqueue failed\n");
nq_hdm_mbo(mbo);
c->hdm_enqueue_task = NULL;
return 0;
}
}
return 0;
}
static int run_enqueue_thread(struct most_channel *c, int channel_id)
{
struct task_struct *task =
kthread_run(hdm_enqueue_thread, c, "hdm_fifo_%d",
channel_id);
if (IS_ERR(task))
return PTR_ERR(task);
c->hdm_enqueue_task = task;
return 0;
}
/**
* arm_mbo - recycle MBO for further usage
* @mbo: buffer object
*
* This puts an MBO back to the list to have it ready for up coming
* tx transactions.
*
* In case the MBO belongs to a channel that recently has been
* poisoned, the MBO is scheduled to be trashed.
* Calls the completion handler of an attached AIM.
*/
static void arm_mbo(struct mbo *mbo)
{
unsigned long flags;
struct most_channel *c;
BUG_ON((!mbo) || (!mbo->context));
c = mbo->context;
if (c->is_poisoned) {
trash_mbo(mbo);
return;
}
spin_lock_irqsave(&c->fifo_lock, flags);
++*mbo->num_buffers_ptr;
list_add_tail(&mbo->list, &c->fifo);
spin_unlock_irqrestore(&c->fifo_lock, flags);
if (c->pipe0.refs && c->pipe0.aim->tx_completion)
c->pipe0.aim->tx_completion(c->iface, c->channel_id);
if (c->pipe1.refs && c->pipe1.aim->tx_completion)
c->pipe1.aim->tx_completion(c->iface, c->channel_id);
}
/**
* arm_mbo_chain - helper function that arms an MBO chain for the HDM
* @c: pointer to interface channel
* @dir: direction of the channel
* @compl: pointer to completion function
*
* This allocates buffer objects including the containing DMA coherent
* buffer and puts them in the fifo.
* Buffers of Rx channels are put in the kthread fifo, hence immediately
* submitted to the HDM.
*
* Returns the number of allocated and enqueued MBOs.
*/
static int arm_mbo_chain(struct most_channel *c, int dir,
void (*compl)(struct mbo *))
{
unsigned int i;
int retval;
struct mbo *mbo;
u32 coherent_buf_size = c->cfg.buffer_size + c->cfg.extra_len;
atomic_set(&c->mbo_nq_level, 0);
for (i = 0; i < c->cfg.num_buffers; i++) {
mbo = kzalloc(sizeof(*mbo), GFP_KERNEL);
if (!mbo) {
retval = i;
goto _exit;
}
mbo->context = c;
mbo->ifp = c->iface;
mbo->hdm_channel_id = c->channel_id;
mbo->virt_address = dma_alloc_coherent(NULL,
coherent_buf_size,
&mbo->bus_address,
GFP_KERNEL);
if (!mbo->virt_address) {
pr_info("WARN: No DMA coherent buffer.\n");
retval = i;
goto _error1;
}
mbo->complete = compl;
mbo->num_buffers_ptr = &dummy_num_buffers;
if (dir == MOST_CH_RX) {
nq_hdm_mbo(mbo);
atomic_inc(&c->mbo_nq_level);
} else {
arm_mbo(mbo);
}
}
return i;
_error1:
kfree(mbo);
_exit:
return retval;
}
/**
* most_submit_mbo - submits an MBO to fifo
* @mbo: pointer to the MBO
*/
void most_submit_mbo(struct mbo *mbo)
{
if (WARN_ONCE(!mbo || !mbo->context,
"bad mbo or missing channel reference\n"))
return;
nq_hdm_mbo(mbo);
}
EXPORT_SYMBOL_GPL(most_submit_mbo);
/**
* most_write_completion - write completion handler
* @mbo: pointer to MBO
*
* This recycles the MBO for further usage. In case the channel has been
* poisoned, the MBO is scheduled to be trashed.
*/
static void most_write_completion(struct mbo *mbo)
{
struct most_channel *c;
BUG_ON((!mbo) || (!mbo->context));
c = mbo->context;
if (mbo->status == MBO_E_INVAL)
pr_info("WARN: Tx MBO status: invalid\n");
if (unlikely(c->is_poisoned || (mbo->status == MBO_E_CLOSE)))
trash_mbo(mbo);
else
arm_mbo(mbo);
}
int channel_has_mbo(struct most_interface *iface, int id, struct core_component *aim)
{
struct most_channel *c = iface->p->channel[id];
unsigned long flags;
int empty;
if (unlikely(!c))
return -EINVAL;
if (c->pipe0.refs && c->pipe1.refs &&
((aim == c->pipe0.aim && c->pipe0.num_buffers <= 0) ||
(aim == c->pipe1.aim && c->pipe1.num_buffers <= 0)))
return 0;
spin_lock_irqsave(&c->fifo_lock, flags);
empty = list_empty(&c->fifo);
spin_unlock_irqrestore(&c->fifo_lock, flags);
return !empty;
}
EXPORT_SYMBOL_GPL(channel_has_mbo);
/**
* most_get_mbo - get pointer to an MBO of pool
* @iface: pointer to interface instance
* @id: channel ID
*
* This attempts to get a free buffer out of the channel fifo.
* Returns a pointer to MBO on success or NULL otherwise.
*/
struct mbo *most_get_mbo(struct most_interface *iface, int id,
struct core_component *aim)
{
struct mbo *mbo;
struct most_channel *c;
unsigned long flags;
int *num_buffers_ptr;
c = iface->p->channel[id];
if (unlikely(!c))
return NULL;
if (c->pipe0.refs && c->pipe1.refs &&
((aim == c->pipe0.aim && c->pipe0.num_buffers <= 0) ||
(aim == c->pipe1.aim && c->pipe1.num_buffers <= 0)))
return NULL;
if (aim == c->pipe0.aim)
num_buffers_ptr = &c->pipe0.num_buffers;
else if (aim == c->pipe1.aim)
num_buffers_ptr = &c->pipe1.num_buffers;
else
num_buffers_ptr = &dummy_num_buffers;
spin_lock_irqsave(&c->fifo_lock, flags);
if (list_empty(&c->fifo)) {
spin_unlock_irqrestore(&c->fifo_lock, flags);
return NULL;
}
mbo = list_pop_mbo(&c->fifo);
--*num_buffers_ptr;
spin_unlock_irqrestore(&c->fifo_lock, flags);
mbo->num_buffers_ptr = num_buffers_ptr;
mbo->buffer_length = c->cfg.buffer_size;
return mbo;
}
EXPORT_SYMBOL_GPL(most_get_mbo);
/**
* most_put_mbo - return buffer to pool
* @mbo: buffer object
*/
void most_put_mbo(struct mbo *mbo)
{
struct most_channel *c = mbo->context;
if (c->cfg.direction == MOST_CH_TX) {
arm_mbo(mbo);
return;
}
nq_hdm_mbo(mbo);
atomic_inc(&c->mbo_nq_level);
}
EXPORT_SYMBOL_GPL(most_put_mbo);
/**
* most_read_completion - read completion handler
* @mbo: pointer to MBO
*
* This function is called by the HDM when data has been received from the
* hardware and copied to the buffer of the MBO.
*
* In case the channel has been poisoned it puts the buffer in the trash queue.
* Otherwise, it passes the buffer to an AIM for further processing.
*/
static void most_read_completion(struct mbo *mbo)
{
struct most_channel *c = mbo->context;
if (unlikely(c->is_poisoned || (mbo->status == MBO_E_CLOSE))) {
trash_mbo(mbo);
return;
}
if (mbo->status == MBO_E_INVAL) {
nq_hdm_mbo(mbo);
atomic_inc(&c->mbo_nq_level);
return;
}
if (atomic_sub_and_test(1, &c->mbo_nq_level))
c->is_starving = 1;
if (c->pipe0.refs && c->pipe0.aim->rx_completion &&
c->pipe0.aim->rx_completion(mbo) == 0)
return;
if (c->pipe1.refs && c->pipe1.aim->rx_completion &&
c->pipe1.aim->rx_completion(mbo) == 0)
return;
most_put_mbo(mbo);
}
/**
* most_start_channel - prepares a channel for communication
* @iface: pointer to interface instance
* @id: channel ID
*
* This prepares the channel for usage. Cross-checks whether the
* channel's been properly configured.
*
* Returns 0 on success or error code otherwise.
*/
int most_start_channel(struct most_interface *iface, int id,
struct core_component *aim)
{
int num_buffer;
int ret;
struct most_channel *c = iface->p->channel[id];
if (unlikely(!c))
return -EINVAL;
mutex_lock(&c->start_mutex);
if (c->pipe0.refs + c->pipe1.refs > 0)
goto out; /* already started by other aim */
if (!try_module_get(iface->mod)) {
pr_info("failed to acquire HDM lock\n");
mutex_unlock(&c->start_mutex);
return -ENOLCK;
}
c->cfg.extra_len = 0;
if (c->iface->configure(c->iface, c->channel_id, &c->cfg)) {
pr_info("channel configuration failed. Go check settings...\n");
ret = -EINVAL;
goto error;
}
init_waitqueue_head(&c->hdm_fifo_wq);
if (c->cfg.direction == MOST_CH_RX)
num_buffer = arm_mbo_chain(c, c->cfg.direction,
most_read_completion);
else
num_buffer = arm_mbo_chain(c, c->cfg.direction,
most_write_completion);
if (unlikely(!num_buffer)) {
pr_info("failed to allocate memory\n");
ret = -ENOMEM;
goto error;
}
ret = run_enqueue_thread(c, id);
if (ret)
goto error;
c->is_starving = 0;
c->pipe0.num_buffers = c->cfg.num_buffers / 2;
c->pipe1.num_buffers = c->cfg.num_buffers - c->pipe0.num_buffers;
atomic_set(&c->mbo_ref, num_buffer);
out:
if (aim == c->pipe0.aim)
c->pipe0.refs++;
if (aim == c->pipe1.aim)
c->pipe1.refs++;
mutex_unlock(&c->start_mutex);
return 0;
error:
module_put(iface->mod);
mutex_unlock(&c->start_mutex);
return ret;
}
EXPORT_SYMBOL_GPL(most_start_channel);
/**
* most_stop_channel - stops a running channel
* @iface: pointer to interface instance
* @id: channel ID
*/
int most_stop_channel(struct most_interface *iface, int id,
struct core_component *aim)
{
struct most_channel *c;
if (unlikely((!iface) || (id >= iface->num_channels) || (id < 0))) {
pr_err("Bad interface or index out of range\n");
return -EINVAL;
}
c = iface->p->channel[id];
if (unlikely(!c))
return -EINVAL;
mutex_lock(&c->start_mutex);
if (c->pipe0.refs + c->pipe1.refs >= 2)
goto out;
if (c->hdm_enqueue_task)
kthread_stop(c->hdm_enqueue_task);
c->hdm_enqueue_task = NULL;
if (iface->mod)
module_put(iface->mod);
c->is_poisoned = true;
if (c->iface->poison_channel(c->iface, c->channel_id)) {
pr_err("Cannot stop channel %d of mdev %s\n", c->channel_id,
c->iface->description);
mutex_unlock(&c->start_mutex);
return -EAGAIN;
}
flush_trash_fifo(c);
flush_channel_fifos(c);
#ifdef CMPL_INTERRUPTIBLE
if (wait_for_completion_interruptible(&c->cleanup)) {
pr_info("Interrupted while clean up ch %d\n", c->channel_id);
mutex_unlock(&c->start_mutex);
return -EINTR;
}
#else
wait_for_completion(&c->cleanup);
#endif
c->is_poisoned = false;
out:
if (aim == c->pipe0.aim)
c->pipe0.refs--;
if (aim == c->pipe1.aim)
c->pipe1.refs--;
mutex_unlock(&c->start_mutex);
return 0;
}
EXPORT_SYMBOL_GPL(most_stop_channel);
/**
* most_register_component - registers an AIM (driver) with the core
* @aim: instance of AIM to be registered
*/
int most_register_component(struct core_component *aim)
{
if (!aim) {
pr_err("Bad driver\n");
return -EINVAL;
}
list_add_tail(&aim->list, &mc.comp_list);
pr_info("registered new application interfacing module %s\n", aim->name);
return 0;
}
EXPORT_SYMBOL_GPL(most_register_component);
static int disconnect_channels(struct device *dev, void *data)
{
struct most_interface *iface;
struct most_channel *c, *tmp;
struct core_component *aim = data;
iface = to_most_interface(dev);
list_for_each_entry_safe(c, tmp, &iface->p->channel_list, list) {
if (c->pipe0.aim == aim || c->pipe1.aim == aim)
aim->disconnect_channel(c->iface, c->channel_id);
if (c->pipe0.aim == aim)
c->pipe0.aim = NULL;
if (c->pipe1.aim == aim)
c->pipe1.aim = NULL;
}
return 0;
}
/**
* most_deregister_component - deregisters an AIM (driver) with the core
* @aim: AIM to be removed
*/
int most_deregister_component(struct core_component *aim)
{
if (!aim) {
pr_err("Bad driver\n");
return -EINVAL;
}
bus_for_each_dev(&mc.bus, NULL, aim, disconnect_channels);
list_del(&aim->list);
pr_info("deregistering module %s\n", aim->name);
return 0;
}
EXPORT_SYMBOL_GPL(most_deregister_component);
static void release_interface(struct device *dev)
{
pr_info("releasing interface dev %s...\n", dev_name(dev));
}
static void release_channel(struct device *dev)
{
pr_info("releasing channel dev %s...\n", dev_name(dev));
}
/**
* most_register_interface - registers an interface with core
* @iface: pointer to the instance of the interface description.
*
* Allocates and initializes a new interface instance and all of its channels.
* Returns a pointer to kobject or an error pointer.
*/
int most_register_interface(struct most_interface *iface)
{
unsigned int i;
int id;
struct most_channel *c;
if (!iface || !iface->enqueue || !iface->configure ||
!iface->poison_channel || (iface->num_channels > MAX_CHANNELS)) {
pr_err("Bad interface or channel overflow\n");
return -EINVAL;
}
id = ida_simple_get(&mdev_id, 0, 0, GFP_KERNEL);
if (id < 0) {
pr_info("Failed to alloc mdev ID\n");
return id;
}
iface->p = kzalloc(sizeof(*iface->p), GFP_KERNEL);
if (!iface->p) {
pr_info("Failed to allocate interface instance\n");
ida_simple_remove(&mdev_id, id);
return -ENOMEM;
}
INIT_LIST_HEAD(&iface->p->channel_list);
iface->p->dev_id = id;
snprintf(iface->p->name, STRING_SIZE, "mdev%d", id);
iface->dev.init_name = iface->p->name;
iface->dev.bus = &mc.bus;
iface->dev.parent = &mc.dev;
iface->dev.groups = interface_attr_groups;
iface->dev.release = release_interface;
if (device_register(&iface->dev)) {
pr_err("registering iface->dev failed\n");
kfree(iface->p);
ida_simple_remove(&mdev_id, id);
return -ENOMEM;
}
for (i = 0; i < iface->num_channels; i++) {
const char *name_suffix = iface->channel_vector[i].name_suffix;
c = kzalloc(sizeof(*c), GFP_KERNEL);
if (!c)
goto free_instance;
if (!name_suffix)
snprintf(c->name, STRING_SIZE, "ch%d", i);
else
snprintf(c->name, STRING_SIZE, "%s", name_suffix);
c->dev.init_name = c->name;
c->dev.parent = &iface->dev;
c->dev.groups = channel_attr_groups;
c->dev.release = release_channel;
if (device_register(&c->dev)) {
pr_err("registering c->dev failed\n");
goto free_instance_nodev;
}
iface->p->channel[i] = c;
c->is_starving = 0;
c->iface = iface;
c->channel_id = i;
c->keep_mbo = false;
c->enqueue_halt = false;
c->is_poisoned = false;
c->cfg.direction = 0;
c->cfg.data_type = 0;
c->cfg.num_buffers = 0;
c->cfg.buffer_size = 0;
c->cfg.subbuffer_size = 0;
c->cfg.packets_per_xact = 0;
spin_lock_init(&c->fifo_lock);
INIT_LIST_HEAD(&c->fifo);
INIT_LIST_HEAD(&c->trash_fifo);
INIT_LIST_HEAD(&c->halt_fifo);
init_completion(&c->cleanup);
atomic_set(&c->mbo_ref, 0);
mutex_init(&c->start_mutex);
mutex_init(&c->nq_mutex);
list_add_tail(&c->list, &iface->p->channel_list);
}
pr_info("registered new MOST device mdev%d (%s)\n",
id, iface->description);
return 0;
free_instance_nodev:
kfree(c);
free_instance:
while (i > 0) {
c = iface->p->channel[--i];
device_unregister(&c->dev);
kfree(c);
}
kfree(iface->p);
device_unregister(&iface->dev);
ida_simple_remove(&mdev_id, id);
return -ENOMEM;
}
EXPORT_SYMBOL_GPL(most_register_interface);
/**
* most_deregister_interface - deregisters an interface with core
* @iface: pointer to the interface instance description.
*
* Before removing an interface instance from the list, all running
* channels are stopped and poisoned.
*/
void most_deregister_interface(struct most_interface *iface)
{
int i;
struct most_channel *c;
pr_info("deregistering MOST device %s (%s)\n", dev_name(&iface->dev), iface->description);
for (i = 0; i < iface->num_channels; i++) {
c = iface->p->channel[i];
if (c->pipe0.aim)
c->pipe0.aim->disconnect_channel(c->iface,
c->channel_id);
if (c->pipe1.aim)
c->pipe1.aim->disconnect_channel(c->iface,
c->channel_id);
c->pipe0.aim = NULL;
c->pipe1.aim = NULL;
list_del(&c->list);
device_unregister(&c->dev);
kfree(c);
}
ida_simple_remove(&mdev_id, iface->p->dev_id);
kfree(iface->p);
device_unregister(&iface->dev);
}
EXPORT_SYMBOL_GPL(most_deregister_interface);
/**
* most_stop_enqueue - prevents core from enqueueing MBOs
* @iface: pointer to interface
* @id: channel id
*
* This is called by an HDM that _cannot_ attend to its duties and
* is imminent to get run over by the core. The core is not going to
* enqueue any further packets unless the flagging HDM calls
* most_resume enqueue().
*/
void most_stop_enqueue(struct most_interface *iface, int id)
{
struct most_channel *c = iface->p->channel[id];
if (!c)
return;
mutex_lock(&c->nq_mutex);
c->enqueue_halt = true;
mutex_unlock(&c->nq_mutex);
}
EXPORT_SYMBOL_GPL(most_stop_enqueue);
/**
* most_resume_enqueue - allow core to enqueue MBOs again
* @iface: pointer to interface
* @id: channel id
*
* This clears the enqueue halt flag and enqueues all MBOs currently
* sitting in the wait fifo.
*/
void most_resume_enqueue(struct most_interface *iface, int id)
{
struct most_channel *c = iface->p->channel[id];
if (!c)
return;
mutex_lock(&c->nq_mutex);
c->enqueue_halt = false;
mutex_unlock(&c->nq_mutex);
wake_up_interruptible(&c->hdm_fifo_wq);
}
EXPORT_SYMBOL_GPL(most_resume_enqueue);
static void release_most_sub(struct device *dev)
{
pr_info("releasing most_subsystem\n");
}
static int __init most_init(void)
{
int err;
pr_info("init()\n");
INIT_LIST_HEAD(&mc.comp_list);
ida_init(&mdev_id);
mc.bus.name = "most",
mc.bus.match = most_match,
mc.drv.name = "most_core",
mc.drv.bus = &mc.bus,
mc.drv.groups = module_attr_groups;
err = bus_register(&mc.bus);
if (err) {
pr_info("Cannot register most bus\n");
return err;
}
mc.class = class_create(THIS_MODULE, "most");
if (IS_ERR(mc.class)) {
pr_info("No udev support.\n");
err = PTR_ERR(mc.class);
goto exit_bus;
}
err = driver_register(&mc.drv);
if (err) {
pr_info("Cannot register core driver\n");
goto exit_class;
}
mc.dev.init_name = "most_bus";
mc.dev.release = release_most_sub;
if (device_register(&mc.dev)) {
err = -ENOMEM;
goto exit_driver;
}
return 0;
exit_driver:
driver_unregister(&mc.drv);
exit_class:
class_destroy(mc.class);
exit_bus:
bus_unregister(&mc.bus);
return err;
}
static void __exit most_exit(void)
{
pr_info("exit core module\n");
device_unregister(&mc.dev);
driver_unregister(&mc.drv);
class_destroy(mc.class);
bus_unregister(&mc.bus);
ida_destroy(&mdev_id);
}
module_init(most_init);
module_exit(most_exit);
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Christian Gromm <christian.gromm@microchip.com>");
MODULE_DESCRIPTION("Core module of stacked MOST Linux driver");
|