// SPDX-License-Identifier: GPL-2.0
/*
* core.c - Implementation of core module of MOST Linux driver stack
*
* Copyright (C) 2013-2020 Microchip Technology Germany II GmbH & Co. KG
*/
#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 <linux/most.h>
#define MAX_CHANNELS 64
#define STRING_SIZE 80
static struct ida mdev_id;
static int dummy_num_buffers;
static struct list_head comp_list;
struct pipe {
struct most_component *comp;
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; /* channel activation synchronization */
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; /* fifo access synchronization */
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" },
{ MOST_CH_ASYNC, "async" },
{ MOST_CH_SYNC, "sync" },
{ MOST_CH_ISOC, "isoc"},
{ MOST_CH_ISOC, "isoc_avp"},
};
/**
* 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; \
})
/**
* most_free_mbo_coherent - free an MBO and its coherent buffer
* @mbo: most buffer
*/
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;
if (c->iface->dma_free)
c->iface->dma_free(mbo, coherent_buf_size);
else
kfree(mbo->virt_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))))
dev_warn(&c->dev, "Channel or 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_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_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_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, "%s",
ch_data_type[i].name);
}
return snprintf(buf, PAGE_SIZE, "unconfigured\n");
}
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_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_dbr_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.dbr_size);
}
#define to_dev_attr(a) container_of(a, struct device_attribute, attr)
static umode_t channel_attr_is_visible(struct kobject *kobj,
struct attribute *attr, int index)
{
struct device_attribute *dev_attr = to_dev_attr(attr);
struct device *dev = kobj_to_dev(kobj);
struct most_channel *c = to_channel(dev);
if (!strcmp(dev_attr->attr.name, "set_dbr_size") &&
(c->iface->interface != ITYPE_MEDIALB_DIM2))
return 0;
if (!strcmp(dev_attr->attr.name, "set_packets_per_xact") &&
(c->iface->interface != ITYPE_USB))
return 0;
return attr->mode;
}
#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_RO(set_buffer_size);
static DEVICE_ATTR_RO(set_number_of_buffers);
static DEVICE_ATTR_RO(set_direction);
static DEVICE_ATTR_RO(set_datatype);
static DEVICE_ATTR_RO(set_subbuffer_size);
static DEVICE_ATTR_RO(set_packets_per_xact);
static DEVICE_ATTR_RO(set_dbr_size);
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),
DEV_ATTR(set_dbr_size),
NULL,
};
static const struct attribute_group channel_attr_group = {
.attrs = channel_attrs,
.is_visible = channel_attr_is_visible,
};
static const struct attribute_group *channel_attr_groups[] = {
&channel_attr_group,
NULL,
};
static ssize_t description_show(struct device *dev,
struct device_attribute *attr,
char *buf)
{
struct most_interface *iface = dev_get_drvdata(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 = dev_get_drvdata(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 const struct attribute_group interface_attr_group = {
.attrs = interface_attrs,
};
static const struct attribute_group *interface_attr_groups[] = {
&interface_attr_group,
NULL,
};
static struct most_component *match_component(char *name)
{
struct most_component *comp;
list_for_each_entry(comp, &comp_list, list) {
if (!strcmp(comp->name, name))
return comp;
}
return NULL;
}
struct show_links_data {
int offs;
char *buf;
};
static int print_links(struct device *dev, void *data)
{
struct show_links_data *d = data;
int offs = d->offs;
char *buf = d->buf;
struct most_channel *c;
struct most_interface *iface = dev_get_drvdata(dev);
list_for_each_entry(c, &iface->p->channel_list, list) {
if (c->pipe0.comp) {
offs += scnprintf(buf + offs,
PAGE_SIZE - offs,
"%s:%s:%s\n",
c->pipe0.comp->name,
dev_name(iface->dev),
dev_name(&c->dev));
}
if (c->pipe1.comp) {
offs += scnprintf(buf + offs,
PAGE_SIZE - offs,
"%s:%s:%s\n",
c->pipe1.comp->name,
dev_name(iface->dev),
dev_name(&c->dev));
}
}
d->offs = offs;
return 0;
}
static int most_match(struct device *dev, const struct device_driver *drv)
{
if (!strcmp(dev_name(dev), "most"))
return 0;
else
return 1;
}
static const struct bus_type mostbus = {
.name = "most",
.match = most_match,
};
static ssize_t links_show(struct device_driver *drv, char *buf)
{
struct show_links_data d = { .buf = buf };
bus_for_each_dev(&mostbus, NULL, &d, print_links);
return d.offs;
}
static ssize_t components_show(struct device_driver *drv, char *buf)
{
struct most_component *comp;
int offs = 0;
list_for_each_entry(comp, &comp_list, list) {
offs += scnprintf(buf + offs, PAGE_SIZE - offs, "%s\n",
comp->name);
}
return offs;
}
/**
* get_channel - get pointer to channel
* @mdev: name of the device interface
* @mdev_ch: name of channel
*/
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_by_name(&mostbus, NULL, mdev);
if (!dev)
return NULL;
put_device(dev);
iface = dev_get_drvdata(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_component(struct most_channel *c,
struct most_component *comp,
char *name,
char *comp_param)
{
int ret;
struct most_component **comp_ptr;
if (!c->pipe0.comp)
comp_ptr = &c->pipe0.comp;
else if (!c->pipe1.comp)
comp_ptr = &c->pipe1.comp;
else
return -ENOSPC;
*comp_ptr = comp;
ret = comp->probe_channel(c->iface, c->channel_id, &c->cfg, name,
comp_param);
if (ret) {
*comp_ptr = NULL;
return ret;
}
return 0;
}
int most_set_cfg_buffer_size(char *mdev, char *mdev_ch, u16 val)
{
struct most_channel *c = get_channel(mdev, mdev_ch);
if (!c)
return -ENODEV;
c->cfg.buffer_size = val;
return 0;
}
int most_set_cfg_subbuffer_size(char *mdev, char *mdev_ch, u16 val)
{
struct most_channel *c = get_channel(mdev, mdev_ch);
if (!c)
return -ENODEV;
c->cfg.subbuffer_size = val;
return 0;
}
int most_set_cfg_dbr_size(char *mdev, char *mdev_ch, u16 val)
{
struct most_channel *c = get_channel(mdev, mdev_ch);
if (!c)
return -ENODEV;
c->cfg.dbr_size = val;
return 0;
}
int most_set_cfg_num_buffers(char *mdev, char *mdev_ch, u16 val)
{
struct most_channel *c = get_channel(mdev, mdev_ch);
if (!c)
return -ENODEV;
c->cfg.num_buffers = val;
return 0;
}
int most_set_cfg_datatype(char *mdev, char *mdev_ch, char *buf)
{
int i;
struct most_channel *c = get_channel(mdev, mdev_ch);
if (!c)
return -ENODEV;
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))
dev_warn(&c->dev, "Invalid attribute settings\n");
return 0;
}
int most_set_cfg_direction(char *mdev, char *mdev_ch, char *buf)
{
struct most_channel *c = get_channel(mdev, mdev_ch);
if (!c)
return -ENODEV;
if (!strcmp(buf, "dir_rx")) {
c->cfg.direction = MOST_CH_RX;
} else if (!strcmp(buf, "rx")) {
c->cfg.direction = MOST_CH_RX;
} else if (!strcmp(buf, "dir_tx")) {
c->cfg.direction = MOST_CH_TX;
} else if (!strcmp(buf, "tx")) {
c->cfg.direction = MOST_CH_TX;
} else {
dev_err(&c->dev, "Invalid direction\n");
return -ENODATA;
}
return 0;
}
int most_set_cfg_packets_xact(char *mdev, char *mdev_ch, u16 val)
{
struct most_channel *c = get_channel(mdev, mdev_ch);
if (!c)
return -ENODEV;
c->cfg.packets_per_xact = val;
return 0;
}
int most_cfg_complete(char *comp_name)
{
struct most_component *comp;
comp = match_component(comp_name);
if (!comp)
return -ENODEV;
return comp->cfg_complete();
}
int most_add_link(char *mdev, char *mdev_ch, char *comp_name, char *link_name,
char *comp_param)
{
struct most_channel *c = get_channel(mdev, mdev_ch);
struct most_component *comp = match_component(comp_name);
if (!c || !comp)
return -ENODEV;
return link_channel_to_component(c, comp, link_name, comp_param);
}
int most_remove_link(char *mdev, char *mdev_ch, char *comp_name)
{
struct most_channel *c;
struct most_component *comp;
comp = match_component(comp_name);
if (!comp)
return -ENODEV;
c = get_channel(mdev, mdev_ch);
if (!c)
return -ENODEV;
if (comp->disconnect_channel(c->iface, c->channel_id))
return -EIO;
if (c->pipe0.comp == comp)
c->pipe0.comp = NULL;
if (c->pipe1.comp == comp)
c->pipe1.comp = NULL;
return 0;
}
#define DRV_ATTR(_name) (&driver_attr_##_name.attr)
static DRIVER_ATTR_RO(links);
static DRIVER_ATTR_RO(components);
static struct attribute *mc_attrs[] = {
DRV_ATTR(links),
DRV_ATTR(components),
NULL,
};
static const struct attribute_group mc_attr_group = {
.attrs = mc_attrs,
};
static const struct attribute_group *mc_attr_groups[] = {
&mc_attr_group,
NULL,
};
static struct device_driver mostbus_driver = {
.name = "most_core",
.bus = &mostbus,
.groups = mc_attr_groups,
};
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)) {
dev_err(&c->dev, "Buffer 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: most buffer
*
* 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 component.
*/
static void arm_mbo(struct mbo *mbo)
{
unsigned long flags;
struct most_channel *c;
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.comp->tx_completion)
c->pipe0.comp->tx_completion(c->iface, c->channel_id);
if (c->pipe1.refs && c->pipe1.comp->tx_completion)
c->pipe1.comp->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;
struct mbo *mbo;
unsigned long flags;
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)
goto flush_fifos;
mbo->context = c;
mbo->ifp = c->iface;
mbo->hdm_channel_id = c->channel_id;
if (c->iface->dma_alloc) {
mbo->virt_address =
c->iface->dma_alloc(mbo, coherent_buf_size);
} else {
mbo->virt_address =
kzalloc(coherent_buf_size, GFP_KERNEL);
}
if (!mbo->virt_address)
goto release_mbo;
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 {
spin_lock_irqsave(&c->fifo_lock, flags);
list_add_tail(&mbo->list, &c->fifo);
spin_unlock_irqrestore(&c->fifo_lock, flags);
}
}
return c->cfg.num_buffers;
release_mbo:
kfree(mbo);
flush_fifos:
flush_channel_fifos(c);
return 0;
}
/**
* most_submit_mbo - submits an MBO to fifo
* @mbo: most buffer
*/
void most_submit_mbo(struct mbo *mbo)
{
if (WARN_ONCE(!mbo || !mbo->context,
"Bad buffer or missing channel reference\n"))
return;
nq_hdm_mbo(mbo);
}
EXPORT_SYMBOL_GPL(most_submit_mbo);
/**
* most_write_completion - write completion handler
* @mbo: most buffer
*
* 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;
c = mbo->context;
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 most_component *comp)
{
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 &&
((comp == c->pipe0.comp && c->pipe0.num_buffers <= 0) ||
(comp == c->pipe1.comp && 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
* @comp: driver component
*
* 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 most_component *comp)
{
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 &&
((comp == c->pipe0.comp && c->pipe0.num_buffers <= 0) ||
(comp == c->pipe1.comp && c->pipe1.num_buffers <= 0)))
return NULL;
if (comp == c->pipe0.comp)
num_buffers_ptr = &c->pipe0.num_buffers;
else if (comp == c->pipe1.comp)
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: most buffer
*/
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: most buffer
*
* 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 component 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.comp->rx_completion &&
c->pipe0.comp->rx_completion(mbo) == 0)
return;
if (c->pipe1.refs && c->pipe1.comp->rx_completion &&
c->pipe1.comp->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
* @comp: driver component
*
* 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 most_component *comp)
{
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 another component */
if (!try_module_get(iface->mod)) {
dev_err(&c->dev, "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)) {
dev_err(&c->dev, "Channel configuration failed. Go check settings...\n");
ret = -EINVAL;
goto err_put_module;
}
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)) {
ret = -ENOMEM;
goto err_put_module;
}
ret = run_enqueue_thread(c, id);
if (ret)
goto err_put_module;
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 (comp == c->pipe0.comp)
c->pipe0.refs++;
if (comp == c->pipe1.comp)
c->pipe1.refs++;
mutex_unlock(&c->start_mutex);
return 0;
err_put_module:
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
* @comp: driver component
*/
int most_stop_channel(struct most_interface *iface, int id,
struct most_component *comp)
{
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)) {
dev_err(&c->dev, "Failed to stop channel %d of interface %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)) {
dev_err(&c->dev, "Interrupted while cleaning up channel %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 (comp == c->pipe0.comp)
c->pipe0.refs--;
if (comp == c->pipe1.comp)
c->pipe1.refs--;
mutex_unlock(&c->start_mutex);
return 0;
}
EXPORT_SYMBOL_GPL(most_stop_channel);
/**
* most_register_component - registers a driver component with the core
* @comp: driver component
*/
int most_register_component(struct most_component *comp)
{
if (!comp) {
pr_err("Bad component\n");
return -EINVAL;
}
list_add_tail(&comp->list, &comp_list);
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 most_component *comp = data;
iface = dev_get_drvdata(dev);
list_for_each_entry_safe(c, tmp, &iface->p->channel_list, list) {
if (c->pipe0.comp == comp || c->pipe1.comp == comp)
comp->disconnect_channel(c->iface, c->channel_id);
if (c->pipe0.comp == comp)
c->pipe0.comp = NULL;
if (c->pipe1.comp == comp)
c->pipe1.comp = NULL;
}
return 0;
}
/**
* most_deregister_component - deregisters a driver component with the core
* @comp: driver component
*/
int most_deregister_component(struct most_component *comp)
{
if (!comp) {
pr_err("Bad component\n");
return -EINVAL;
}
bus_for_each_dev(&mostbus, NULL, comp, disconnect_channels);
list_del(&comp->list);
return 0;
}
EXPORT_SYMBOL_GPL(most_deregister_component);
static void release_channel(struct device *dev)
{
struct most_channel *c = to_channel(dev);
kfree(c);
}
/**
* most_register_interface - registers an interface with core
* @iface: device interface
*
* 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))
return -EINVAL;
id = ida_alloc(&mdev_id, GFP_KERNEL);
if (id < 0) {
dev_err(iface->dev, "Failed to allocate device ID\n");
return id;
}
iface->p = kzalloc(sizeof(*iface->p), GFP_KERNEL);
if (!iface->p) {
ida_free(&mdev_id, id);
return -ENOMEM;
}
INIT_LIST_HEAD(&iface->p->channel_list);
iface->p->dev_id = id;
strscpy(iface->p->name, iface->description, sizeof(iface->p->name));
iface->dev->bus = &mostbus;
iface->dev->groups = interface_attr_groups;
dev_set_drvdata(iface->dev, iface);
if (device_register(iface->dev)) {
dev_err(iface->dev, "Failed to register interface device\n");
kfree(iface->p);
put_device(iface->dev);
ida_free(&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 err_free_resources;
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;
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);
if (device_register(&c->dev)) {
dev_err(&c->dev, "Failed to register channel device\n");
goto err_free_most_channel;
}
}
most_interface_register_notify(iface->description);
return 0;
err_free_most_channel:
put_device(&c->dev);
err_free_resources:
while (i > 0) {
c = iface->p->channel[--i];
device_unregister(&c->dev);
}
kfree(iface->p);
device_unregister(iface->dev);
ida_free(&mdev_id, id);
return -ENOMEM;
}
EXPORT_SYMBOL_GPL(most_register_interface);
/**
* most_deregister_interface - deregisters an interface with core
* @iface: device interface
*
* 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;
for (i = 0; i < iface->num_channels; i++) {
c = iface->p->channel[i];
if (c->pipe0.comp)
c->pipe0.comp->disconnect_channel(c->iface,
c->channel_id);
if (c->pipe1.comp)
c->pipe1.comp->disconnect_channel(c->iface,
c->channel_id);
c->pipe0.comp = NULL;
c->pipe1.comp = NULL;
list_del(&c->list);
device_unregister(&c->dev);
}
ida_free(&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 int __init most_init(void)
{
int err;
INIT_LIST_HEAD(&comp_list);
ida_init(&mdev_id);
err = bus_register(&mostbus);
if (err) {
pr_err("Failed to register most bus\n");
return err;
}
err = driver_register(&mostbus_driver);
if (err) {
pr_err("Failed to register core driver\n");
goto err_unregister_bus;
}
configfs_init();
return 0;
err_unregister_bus:
bus_unregister(&mostbus);
return err;
}
static void __exit most_exit(void)
{
driver_unregister(&mostbus_driver);
bus_unregister(&mostbus);
ida_destroy(&mdev_id);
}
subsys_initcall(most_init);
module_exit(most_exit);
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Christian Gromm <[email protected]>");
MODULE_DESCRIPTION("Core module of stacked MOST Linux driver");
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