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-rw-r--r--drivers/most/core.c1488
1 files changed, 1488 insertions, 0 deletions
diff --git a/drivers/most/core.c b/drivers/most/core.c
new file mode 100644
index 000000000..e4412c7d2
--- /dev/null
+++ b/drivers/most/core.c
@@ -0,0 +1,1488 @@
+// 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, struct device_driver *drv)
+{
+ if (!strcmp(dev_name(dev), "most"))
+ return 0;
+ else
+ return 1;
+}
+
+static 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_simple_get(&mdev_id, 0, 0, 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_simple_remove(&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_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 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_simple_remove(&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_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 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 <christian.gromm@microchip.com>");
+MODULE_DESCRIPTION("Core module of stacked MOST Linux driver");