Orange Pi5 kernel

// SPDX-License-Identifier: GPL-2.0
/*
 * System Trace Module (STM) infrastructure
 * Copyright (c) 2014, Intel Corporation.
 *
 * STM class implements generic infrastructure for  System Trace Module devices
 * as defined in MIPI STPv2 specification.
 */
 
#include <linux/pm_runtime.h>
#include <linux/uaccess.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/device.h>
#include <linux/compat.h>
#include <linux/kdev_t.h>
#include <linux/srcu.h>
#include <linux/slab.h>
#include <linux/stm.h>
#include <linux/fs.h>
#include <linux/mm.h>
#include <linux/vmalloc.h>
#include "stm.h"
 
#include <uapi/linux/stm.h>
 
static unsigned int stm_core_up;
 
/*
 * The SRCU here makes sure that STM device doesn't disappear from under a
 * stm_source_write() caller, which may want to have as little overhead as
 * possible.
 */
static struct srcu_struct stm_source_srcu;
 
static ssize_t masters_show(struct device *dev,
<------><------><------>    struct device_attribute *attr,
<------><------><------>    char *buf)
{
<------>struct stm_device *stm = to_stm_device(dev);
<------>int ret;
 
<------>ret = sprintf(buf, "%u %u\n", stm->data->sw_start, stm->data->sw_end);
 
<------>return ret;
}
 
static DEVICE_ATTR_RO(masters);
 
static ssize_t channels_show(struct device *dev,
<------><------><------>     struct device_attribute *attr,
<------><------><------>     char *buf)
{
<------>struct stm_device *stm = to_stm_device(dev);
<------>int ret;
 
<------>ret = sprintf(buf, "%u\n", stm->data->sw_nchannels);
 
<------>return ret;
}
 
static DEVICE_ATTR_RO(channels);
 
static ssize_t hw_override_show(struct device *dev,
<------><------><------><------>struct device_attribute *attr,
<------><------><------><------>char *buf)
{
<------>struct stm_device *stm = to_stm_device(dev);
<------>int ret;
 
<------>ret = sprintf(buf, "%u\n", stm->data->hw_override);
 
<------>return ret;
}
 
static DEVICE_ATTR_RO(hw_override);
 
static struct attribute *stm_attrs[] = {
<------>&dev_attr_masters.attr,
<------>&dev_attr_channels.attr,
<------>&dev_attr_hw_override.attr,
<------>NULL,
};
 
ATTRIBUTE_GROUPS(stm);
 
static struct class stm_class = {
<------>.name		= "stm",
<------>.dev_groups	= stm_groups,
};
 
/**
 * stm_find_device() - find stm device by name
 * @buf:	character buffer containing the name
 *
 * This is called when either policy gets assigned to an stm device or an
 * stm_source device gets linked to an stm device.
 *
 * This grabs device's reference (get_device()) and module reference, both
 * of which the calling path needs to make sure to drop with stm_put_device().
 *
 * Return:	stm device pointer or null if lookup failed.
 */
struct stm_device *stm_find_device(const char *buf)
{
<------>struct stm_device *stm;
<------>struct device *dev;
 
<------>if (!stm_core_up)
<------><------>return NULL;
 
<------>dev = class_find_device_by_name(&stm_class, buf);
<------>if (!dev)
<------><------>return NULL;
 
<------>stm = to_stm_device(dev);
<------>if (!try_module_get(stm->owner)) {
<------><------>/* matches class_find_device() above */
<------><------>put_device(dev);
<------><------>return NULL;
<------>}
 
<------>return stm;
}
 
/**
 * stm_put_device() - drop references on the stm device
 * @stm:	stm device, previously acquired by stm_find_device()
 *
 * This drops the module reference and device reference taken by
 * stm_find_device() or stm_char_open().
 */
void stm_put_device(struct stm_device *stm)
{
<------>module_put(stm->owner);
<------>put_device(&stm->dev);
}
 
/*
 * Internally we only care about software-writable masters here, that is the
 * ones in the range [stm_data->sw_start..stm_data..sw_end], however we need
 * original master numbers to be visible externally, since they are the ones
 * that will appear in the STP stream. Thus, the internal bookkeeping uses
 * $master - stm_data->sw_start to reference master descriptors and such.
 */
 
#define __stm_master(_s, _m)				\
<------>((_s)->masters[(_m) - (_s)->data->sw_start])
 
static inline struct stp_master *
stm_master(struct stm_device *stm, unsigned int idx)
{
<------>if (idx < stm->data->sw_start || idx > stm->data->sw_end)
<------><------>return NULL;
 
<------>return __stm_master(stm, idx);
}
 
static int stp_master_alloc(struct stm_device *stm, unsigned int idx)
{
<------>struct stp_master *master;
 
<------>master = kzalloc(struct_size(master, chan_map,
<------><------><------><------>     BITS_TO_LONGS(stm->data->sw_nchannels)),
<------><------><------> GFP_ATOMIC);
<------>if (!master)
<------><------>return -ENOMEM;
 
<------>master->nr_free = stm->data->sw_nchannels;
<------>__stm_master(stm, idx) = master;
 
<------>return 0;
}
 
static void stp_master_free(struct stm_device *stm, unsigned int idx)
{
<------>struct stp_master *master = stm_master(stm, idx);
 
<------>if (!master)
<------><------>return;
 
<------>__stm_master(stm, idx) = NULL;
<------>kfree(master);
}
 
static void stm_output_claim(struct stm_device *stm, struct stm_output *output)
{
<------>struct stp_master *master = stm_master(stm, output->master);
 
<------>lockdep_assert_held(&stm->mc_lock);
<------>lockdep_assert_held(&output->lock);
 
<------>if (WARN_ON_ONCE(master->nr_free < output->nr_chans))
<------><------>return;
 
<------>bitmap_allocate_region(&master->chan_map[0], output->channel,
<------><------><------>       ilog2(output->nr_chans));
 
<------>master->nr_free -= output->nr_chans;
}
 
static void
stm_output_disclaim(struct stm_device *stm, struct stm_output *output)
{
<------>struct stp_master *master = stm_master(stm, output->master);
 
<------>lockdep_assert_held(&stm->mc_lock);
<------>lockdep_assert_held(&output->lock);
 
<------>bitmap_release_region(&master->chan_map[0], output->channel,
<------><------><------>      ilog2(output->nr_chans));
 
<------>master->nr_free += output->nr_chans;
<------>output->nr_chans = 0;
}
 
/*
 * This is like bitmap_find_free_region(), except it can ignore @start bits
 * at the beginning.
 */
static int find_free_channels(unsigned long *bitmap, unsigned int start,
<------><------><------>      unsigned int end, unsigned int width)
{
<------>unsigned int pos;
<------>int i;
 
<------>for (pos = start; pos < end + 1; pos = ALIGN(pos, width)) {
<------><------>pos = find_next_zero_bit(bitmap, end + 1, pos);
<------><------>if (pos + width > end + 1)
<------><------><------>break;
 
<------><------>if (pos & (width - 1))
<------><------><------>continue;
 
<------><------>for (i = 1; i < width && !test_bit(pos + i, bitmap); i++)
<------><------><------>;
<------><------>if (i == width)
<------><------><------>return pos;
 
<------><------>/* step over [pos..pos+i) to continue search */
<------><------>pos += i;
<------>}
 
<------>return -1;
}
 
static int
stm_find_master_chan(struct stm_device *stm, unsigned int width,
<------><------>     unsigned int *mstart, unsigned int mend,
<------><------>     unsigned int *cstart, unsigned int cend)
{
<------>struct stp_master *master;
<------>unsigned int midx;
<------>int pos, err;
 
<------>for (midx = *mstart; midx <= mend; midx++) {
<------><------>if (!stm_master(stm, midx)) {
<------><------><------>err = stp_master_alloc(stm, midx);
<------><------><------>if (err)
<------><------><------><------>return err;
<------><------>}
 
<------><------>master = stm_master(stm, midx);
 
<------><------>if (!master->nr_free)
<------><------><------>continue;
 
<------><------>pos = find_free_channels(master->chan_map, *cstart, cend,
<------><------><------><------><------> width);
<------><------>if (pos < 0)
<------><------><------>continue;
 
<------><------>*mstart = midx;
<------><------>*cstart = pos;
<------><------>return 0;
<------>}
 
<------>return -ENOSPC;
}
 
static int stm_output_assign(struct stm_device *stm, unsigned int width,
<------><------><------>     struct stp_policy_node *policy_node,
<------><------><------>     struct stm_output *output)
{
<------>unsigned int midx, cidx, mend, cend;
<------>int ret = -EINVAL;
 
<------>if (width > stm->data->sw_nchannels)
<------><------>return -EINVAL;
 
<------>/* We no longer accept policy_node==NULL here */
<------>if (WARN_ON_ONCE(!policy_node))
<------><------>return -EINVAL;
 
<------>/*
<------> * Also, the caller holds reference to policy_node, so it won't
<------> * disappear on us.
<------> */
<------>stp_policy_node_get_ranges(policy_node, &midx, &mend, &cidx, &cend);
 
<------>spin_lock(&stm->mc_lock);
<------>spin_lock(&output->lock);
<------>/* output is already assigned -- shouldn't happen */
<------>if (WARN_ON_ONCE(output->nr_chans))
<------><------>goto unlock;
 
<------>ret = stm_find_master_chan(stm, width, &midx, mend, &cidx, cend);
<------>if (ret < 0)
<------><------>goto unlock;
 
<------>output->master = midx;
<------>output->channel = cidx;
<------>output->nr_chans = width;
<------>if (stm->pdrv->output_open) {
<------><------>void *priv = stp_policy_node_priv(policy_node);
 
<------><------>if (WARN_ON_ONCE(!priv))
<------><------><------>goto unlock;
 
<------><------>/* configfs subsys mutex is held by the caller */
<------><------>ret = stm->pdrv->output_open(priv, output);
<------><------>if (ret)
<------><------><------>goto unlock;
<------>}
 
<------>stm_output_claim(stm, output);
<------>dev_dbg(&stm->dev, "assigned %u:%u (+%u)\n", midx, cidx, width);
 
<------>ret = 0;
unlock:
<------>if (ret)
<------><------>output->nr_chans = 0;
 
<------>spin_unlock(&output->lock);
<------>spin_unlock(&stm->mc_lock);
 
<------>return ret;
}
 
static void stm_output_free(struct stm_device *stm, struct stm_output *output)
{
<------>spin_lock(&stm->mc_lock);
<------>spin_lock(&output->lock);
<------>if (output->nr_chans)
<------><------>stm_output_disclaim(stm, output);
<------>if (stm->pdrv && stm->pdrv->output_close)
<------><------>stm->pdrv->output_close(output);
<------>spin_unlock(&output->lock);
<------>spin_unlock(&stm->mc_lock);
}
 
static void stm_output_init(struct stm_output *output)
{
<------>spin_lock_init(&output->lock);
}
 
static int major_match(struct device *dev, const void *data)
{
<------>unsigned int major = *(unsigned int *)data;
 
<------>return MAJOR(dev->devt) == major;
}
 
/*
 * Framing protocol management
 * Modules can implement STM protocol drivers and (un-)register them
 * with the STM class framework.
 */
static struct list_head stm_pdrv_head;
static struct mutex stm_pdrv_mutex;
 
struct stm_pdrv_entry {
<------>struct list_head			entry;
<------>const struct stm_protocol_driver	*pdrv;
<------>const struct config_item_type		*node_type;
};
 
static const struct stm_pdrv_entry *
__stm_lookup_protocol(const char *name)
{
<------>struct stm_pdrv_entry *pe;
 
<------>/*
<------> * If no name is given (NULL or ""), fall back to "p_basic".
<------> */
<------>if (!name || !*name)
<------><------>name = "p_basic";
 
<------>list_for_each_entry(pe, &stm_pdrv_head, entry) {
<------><------>if (!strcmp(name, pe->pdrv->name))
<------><------><------>return pe;
<------>}
 
<------>return NULL;
}
 
int stm_register_protocol(const struct stm_protocol_driver *pdrv)
{
<------>struct stm_pdrv_entry *pe = NULL;
<------>int ret = -ENOMEM;
 
<------>mutex_lock(&stm_pdrv_mutex);
 
<------>if (__stm_lookup_protocol(pdrv->name)) {
<------><------>ret = -EEXIST;
<------><------>goto unlock;
<------>}
 
<------>pe = kzalloc(sizeof(*pe), GFP_KERNEL);
<------>if (!pe)
<------><------>goto unlock;
 
<------>if (pdrv->policy_attr) {
<------><------>pe->node_type = get_policy_node_type(pdrv->policy_attr);
<------><------>if (!pe->node_type)
<------><------><------>goto unlock;
<------>}
 
<------>list_add_tail(&pe->entry, &stm_pdrv_head);
<------>pe->pdrv = pdrv;
 
<------>ret = 0;
unlock:
<------>mutex_unlock(&stm_pdrv_mutex);
 
<------>if (ret)
<------><------>kfree(pe);
 
<------>return ret;
}
EXPORT_SYMBOL_GPL(stm_register_protocol);
 
void stm_unregister_protocol(const struct stm_protocol_driver *pdrv)
{
<------>struct stm_pdrv_entry *pe, *iter;
 
<------>mutex_lock(&stm_pdrv_mutex);
 
<------>list_for_each_entry_safe(pe, iter, &stm_pdrv_head, entry) {
<------><------>if (pe->pdrv == pdrv) {
<------><------><------>list_del(&pe->entry);
 
<------><------><------>if (pe->node_type) {
<------><------><------><------>kfree(pe->node_type->ct_attrs);
<------><------><------><------>kfree(pe->node_type);
<------><------><------>}
<------><------><------>kfree(pe);
<------><------><------>break;
<------><------>}
<------>}
 
<------>mutex_unlock(&stm_pdrv_mutex);
}
EXPORT_SYMBOL_GPL(stm_unregister_protocol);
 
static bool stm_get_protocol(const struct stm_protocol_driver *pdrv)
{
<------>return try_module_get(pdrv->owner);
}
 
void stm_put_protocol(const struct stm_protocol_driver *pdrv)
{
<------>module_put(pdrv->owner);
}
 
int stm_lookup_protocol(const char *name,
<------><------><------>const struct stm_protocol_driver **pdrv,
<------><------><------>const struct config_item_type **node_type)
{
<------>const struct stm_pdrv_entry *pe;
 
<------>mutex_lock(&stm_pdrv_mutex);
 
<------>pe = __stm_lookup_protocol(name);
<------>if (pe && pe->pdrv && stm_get_protocol(pe->pdrv)) {
<------><------>*pdrv = pe->pdrv;
<------><------>*node_type = pe->node_type;
<------>}
 
<------>mutex_unlock(&stm_pdrv_mutex);
 
<------>return pe ? 0 : -ENOENT;
}
 
static int stm_char_open(struct inode *inode, struct file *file)
{
<------>struct stm_file *stmf;
<------>struct device *dev;
<------>unsigned int major = imajor(inode);
<------>int err = -ENOMEM;
 
<------>dev = class_find_device(&stm_class, NULL, &major, major_match);
<------>if (!dev)
<------><------>return -ENODEV;
 
<------>stmf = kzalloc(sizeof(*stmf), GFP_KERNEL);
<------>if (!stmf)
<------><------>goto err_put_device;
 
<------>err = -ENODEV;
<------>stm_output_init(&stmf->output);
<------>stmf->stm = to_stm_device(dev);
 
<------>if (!try_module_get(stmf->stm->owner))
<------><------>goto err_free;
 
<------>file->private_data = stmf;
 
<------>return nonseekable_open(inode, file);
 
err_free:
<------>kfree(stmf);
err_put_device:
<------>/* matches class_find_device() above */
<------>put_device(dev);
 
<------>return err;
}
 
static int stm_char_release(struct inode *inode, struct file *file)
{
<------>struct stm_file *stmf = file->private_data;
<------>struct stm_device *stm = stmf->stm;
 
<------>if (stm->data->unlink)
<------><------>stm->data->unlink(stm->data, stmf->output.master,
<------><------><------><------>  stmf->output.channel);
 
<------>stm_output_free(stm, &stmf->output);
 
<------>/*
<------> * matches the stm_char_open()'s
<------> * class_find_device() + try_module_get()
<------> */
<------>stm_put_device(stm);
<------>kfree(stmf);
 
<------>return 0;
}
 
static int
stm_assign_first_policy(struct stm_device *stm, struct stm_output *output,
<------><------><------>char **ids, unsigned int width)
{
<------>struct stp_policy_node *pn;
<------>int err, n;
 
<------>/*
<------> * On success, stp_policy_node_lookup() will return holding the
<------> * configfs subsystem mutex, which is then released in
<------> * stp_policy_node_put(). This allows the pdrv->output_open() in
<------> * stm_output_assign() to serialize against the attribute accessors.
<------> */
<------>for (n = 0, pn = NULL; ids[n] && !pn; n++)
<------><------>pn = stp_policy_node_lookup(stm, ids[n]);
 
<------>if (!pn)
<------><------>return -EINVAL;
 
<------>err = stm_output_assign(stm, width, pn, output);
 
<------>stp_policy_node_put(pn);
 
<------>return err;
}
 
/**
 * stm_data_write() - send the given payload as data packets
 * @data:	stm driver's data
 * @m:		STP master
 * @c:		STP channel
 * @ts_first:	timestamp the first packet
 * @buf:	data payload buffer
 * @count:	data payload size
 */
ssize_t notrace stm_data_write(struct stm_data *data, unsigned int m,
<------><------><------>       unsigned int c, bool ts_first, const void *buf,
<------><------><------>       size_t count)
{
<------>unsigned int flags = ts_first ? STP_PACKET_TIMESTAMPED : 0;
<------>ssize_t sz;
<------>size_t pos;
 
<------>for (pos = 0, sz = 0; pos < count; pos += sz) {
<------><------>sz = min_t(unsigned int, count - pos, 8);
<------><------>sz = data->packet(data, m, c, STP_PACKET_DATA, flags, sz,
<------><------><------><------>  &((u8 *)buf)[pos]);
<------><------>if (sz <= 0)
<------><------><------>break;
 
<------><------>if (ts_first) {
<------><------><------>flags = 0;
<------><------><------>ts_first = false;
<------><------>}
<------>}
 
<------>return sz < 0 ? sz : pos;
}
EXPORT_SYMBOL_GPL(stm_data_write);
 
static ssize_t notrace
stm_write(struct stm_device *stm, struct stm_output *output,
<------>  unsigned int chan, const char *buf, size_t count)
{
<------>int err;
 
<------>/* stm->pdrv is serialized against policy_mutex */
<------>if (!stm->pdrv)
<------><------>return -ENODEV;
 
<------>err = stm->pdrv->write(stm->data, output, chan, buf, count);
<------>if (err < 0)
<------><------>return err;
 
<------>return err;
}
 
static ssize_t stm_char_write(struct file *file, const char __user *buf,
<------><------><------>      size_t count, loff_t *ppos)
{
<------>struct stm_file *stmf = file->private_data;
<------>struct stm_device *stm = stmf->stm;
<------>char *kbuf;
<------>int err;
 
<------>if (count + 1 > PAGE_SIZE)
<------><------>count = PAGE_SIZE - 1;
 
<------>/*
<------> * If no m/c have been assigned to this writer up to this
<------> * point, try to use the task name and "default" policy entries.
<------> */
<------>if (!stmf->output.nr_chans) {
<------><------>char comm[sizeof(current->comm)];
<------><------>char *ids[] = { comm, "default", NULL };
 
<------><------>get_task_comm(comm, current);
 
<------><------>err = stm_assign_first_policy(stmf->stm, &stmf->output, ids, 1);
<------><------>/*
<------><------> * EBUSY means that somebody else just assigned this
<------><------> * output, which is just fine for write()
<------><------> */
<------><------>if (err)
<------><------><------>return err;
<------>}
 
<------>kbuf = kmalloc(count + 1, GFP_KERNEL);
<------>if (!kbuf)
<------><------>return -ENOMEM;
 
<------>err = copy_from_user(kbuf, buf, count);
<------>if (err) {
<------><------>kfree(kbuf);
<------><------>return -EFAULT;
<------>}
 
<------>pm_runtime_get_sync(&stm->dev);
 
<------>count = stm_write(stm, &stmf->output, 0, kbuf, count);
 
<------>pm_runtime_mark_last_busy(&stm->dev);
<------>pm_runtime_put_autosuspend(&stm->dev);
<------>kfree(kbuf);
 
<------>return count;
}
 
static void stm_mmap_open(struct vm_area_struct *vma)
{
<------>struct stm_file *stmf = vma->vm_file->private_data;
<------>struct stm_device *stm = stmf->stm;
 
<------>pm_runtime_get(&stm->dev);
}
 
static void stm_mmap_close(struct vm_area_struct *vma)
{
<------>struct stm_file *stmf = vma->vm_file->private_data;
<------>struct stm_device *stm = stmf->stm;
 
<------>pm_runtime_mark_last_busy(&stm->dev);
<------>pm_runtime_put_autosuspend(&stm->dev);
}
 
static const struct vm_operations_struct stm_mmap_vmops = {
<------>.open	= stm_mmap_open,
<------>.close	= stm_mmap_close,
};
 
static int stm_char_mmap(struct file *file, struct vm_area_struct *vma)
{
<------>struct stm_file *stmf = file->private_data;
<------>struct stm_device *stm = stmf->stm;
<------>unsigned long size, phys;
 
<------>if (!stm->data->mmio_addr)
<------><------>return -EOPNOTSUPP;
 
<------>if (vma->vm_pgoff)
<------><------>return -EINVAL;
 
<------>size = vma->vm_end - vma->vm_start;
 
<------>if (stmf->output.nr_chans * stm->data->sw_mmiosz != size)
<------><------>return -EINVAL;
 
<------>phys = stm->data->mmio_addr(stm->data, stmf->output.master,
<------><------><------><------>    stmf->output.channel,
<------><------><------><------>    stmf->output.nr_chans);
 
<------>if (!phys)
<------><------>return -EINVAL;
 
<------>pm_runtime_get_sync(&stm->dev);
 
<------>vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);
<------>vma->vm_flags |= VM_IO | VM_DONTEXPAND | VM_DONTDUMP;
<------>vma->vm_ops = &stm_mmap_vmops;
<------>vm_iomap_memory(vma, phys, size);
 
<------>return 0;
}
 
static int stm_char_policy_set_ioctl(struct stm_file *stmf, void __user *arg)
{
<------>struct stm_device *stm = stmf->stm;
<------>struct stp_policy_id *id;
<------>char *ids[] = { NULL, NULL };
<------>int ret = -EINVAL, wlimit = 1;
<------>u32 size;
 
<------>if (stmf->output.nr_chans)
<------><------>return -EBUSY;
 
<------>if (copy_from_user(&size, arg, sizeof(size)))
<------><------>return -EFAULT;
 
<------>if (size < sizeof(*id) || size >= PATH_MAX + sizeof(*id))
<------><------>return -EINVAL;
 
<------>/*
<------> * size + 1 to make sure the .id string at the bottom is terminated,
<------> * which is also why memdup_user() is not useful here
<------> */
<------>id = kzalloc(size + 1, GFP_KERNEL);
<------>if (!id)
<------><------>return -ENOMEM;
 
<------>if (copy_from_user(id, arg, size)) {
<------><------>ret = -EFAULT;
<------><------>goto err_free;
<------>}
 
<------>if (id->__reserved_0 || id->__reserved_1)
<------><------>goto err_free;
 
<------>if (stm->data->sw_mmiosz)
<------><------>wlimit = PAGE_SIZE / stm->data->sw_mmiosz;
 
<------>if (id->width < 1 || id->width > wlimit)
<------><------>goto err_free;
 
<------>ids[0] = id->id;
<------>ret = stm_assign_first_policy(stmf->stm, &stmf->output, ids,
<------><------><------><------>      id->width);
<------>if (ret)
<------><------>goto err_free;
 
<------>if (stm->data->link)
<------><------>ret = stm->data->link(stm->data, stmf->output.master,
<------><------><------><------>      stmf->output.channel);
 
<------>if (ret)
<------><------>stm_output_free(stmf->stm, &stmf->output);
 
err_free:
<------>kfree(id);
 
<------>return ret;
}
 
static int stm_char_policy_get_ioctl(struct stm_file *stmf, void __user *arg)
{
<------>struct stp_policy_id id = {
<------><------>.size		= sizeof(id),
<------><------>.master		= stmf->output.master,
<------><------>.channel	= stmf->output.channel,
<------><------>.width		= stmf->output.nr_chans,
<------><------>.__reserved_0	= 0,
<------><------>.__reserved_1	= 0,
<------>};
 
<------>return copy_to_user(arg, &id, id.size) ? -EFAULT : 0;
}
 
static long
stm_char_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
{
<------>struct stm_file *stmf = file->private_data;
<------>struct stm_data *stm_data = stmf->stm->data;
<------>int err = -ENOTTY;
<------>u64 options;
 
<------>switch (cmd) {
<------>case STP_POLICY_ID_SET:
<------><------>err = stm_char_policy_set_ioctl(stmf, (void __user *)arg);
<------><------>if (err)
<------><------><------>return err;
 
<------><------>return stm_char_policy_get_ioctl(stmf, (void __user *)arg);
 
<------>case STP_POLICY_ID_GET:
<------><------>return stm_char_policy_get_ioctl(stmf, (void __user *)arg);
 
<------>case STP_SET_OPTIONS:
<------><------>if (copy_from_user(&options, (u64 __user *)arg, sizeof(u64)))
<------><------><------>return -EFAULT;
 
<------><------>if (stm_data->set_options)
<------><------><------>err = stm_data->set_options(stm_data,
<------><------><------><------><------><------>    stmf->output.master,
<------><------><------><------><------><------>    stmf->output.channel,
<------><------><------><------><------><------>    stmf->output.nr_chans,
<------><------><------><------><------><------>    options);
 
<------><------>break;
<------>default:
<------><------>break;
<------>}
 
<------>return err;
}
 
static const struct file_operations stm_fops = {
<------>.open		= stm_char_open,
<------>.release	= stm_char_release,
<------>.write		= stm_char_write,
<------>.mmap		= stm_char_mmap,
<------>.unlocked_ioctl	= stm_char_ioctl,
<------>.compat_ioctl	= compat_ptr_ioctl,
<------>.llseek		= no_llseek,
};
 
static void stm_device_release(struct device *dev)
{
<------>struct stm_device *stm = to_stm_device(dev);
 
<------>vfree(stm);
}
 
int stm_register_device(struct device *parent, struct stm_data *stm_data,
<------><------><------>struct module *owner)
{
<------>struct stm_device *stm;
<------>unsigned int nmasters;
<------>int err = -ENOMEM;
 
<------>if (!stm_core_up)
<------><------>return -EPROBE_DEFER;
 
<------>if (!stm_data->packet || !stm_data->sw_nchannels)
<------><------>return -EINVAL;
 
<------>nmasters = stm_data->sw_end - stm_data->sw_start + 1;
<------>stm = vzalloc(sizeof(*stm) + nmasters * sizeof(void *));
<------>if (!stm)
<------><------>return -ENOMEM;
 
<------>stm->major = register_chrdev(0, stm_data->name, &stm_fops);
<------>if (stm->major < 0)
<------><------>goto err_free;
 
<------>device_initialize(&stm->dev);
<------>stm->dev.devt = MKDEV(stm->major, 0);
<------>stm->dev.class = &stm_class;
<------>stm->dev.parent = parent;
<------>stm->dev.release = stm_device_release;
 
<------>mutex_init(&stm->link_mutex);
<------>spin_lock_init(&stm->link_lock);
<------>INIT_LIST_HEAD(&stm->link_list);
 
<------>/* initialize the object before it is accessible via sysfs */
<------>spin_lock_init(&stm->mc_lock);
<------>mutex_init(&stm->policy_mutex);
<------>stm->sw_nmasters = nmasters;
<------>stm->owner = owner;
<------>stm->data = stm_data;
<------>stm_data->stm = stm;
 
<------>err = kobject_set_name(&stm->dev.kobj, "%s", stm_data->name);
<------>if (err)
<------><------>goto err_device;
 
<------>err = device_add(&stm->dev);
<------>if (err)
<------><------>goto err_device;
 
<------>/*
<------> * Use delayed autosuspend to avoid bouncing back and forth
<------> * on recurring character device writes, with the initial
<------> * delay time of 2 seconds.
<------> */
<------>pm_runtime_no_callbacks(&stm->dev);
<------>pm_runtime_use_autosuspend(&stm->dev);
<------>pm_runtime_set_autosuspend_delay(&stm->dev, 2000);
<------>pm_runtime_set_suspended(&stm->dev);
<------>pm_runtime_enable(&stm->dev);
 
<------>return 0;
 
err_device:
<------>unregister_chrdev(stm->major, stm_data->name);
 
<------>/* matches device_initialize() above */
<------>put_device(&stm->dev);
err_free:
<------>vfree(stm);
 
<------>return err;
}
EXPORT_SYMBOL_GPL(stm_register_device);
 
static int __stm_source_link_drop(struct stm_source_device *src,
<------><------><------><------>  struct stm_device *stm);
 
void stm_unregister_device(struct stm_data *stm_data)
{
<------>struct stm_device *stm = stm_data->stm;
<------>struct stm_source_device *src, *iter;
<------>int i, ret;
 
<------>pm_runtime_dont_use_autosuspend(&stm->dev);
<------>pm_runtime_disable(&stm->dev);
 
<------>mutex_lock(&stm->link_mutex);
<------>list_for_each_entry_safe(src, iter, &stm->link_list, link_entry) {
<------><------>ret = __stm_source_link_drop(src, stm);
<------><------>/*
<------><------> * src <-> stm link must not change under the same
<------><------> * stm::link_mutex, so complain loudly if it has;
<------><------> * also in this situation ret!=0 means this src is
<------><------> * not connected to this stm and it should be otherwise
<------><------> * safe to proceed with the tear-down of stm.
<------><------> */
<------><------>WARN_ON_ONCE(ret);
<------>}
<------>mutex_unlock(&stm->link_mutex);
 
<------>synchronize_srcu(&stm_source_srcu);
 
<------>unregister_chrdev(stm->major, stm_data->name);
 
<------>mutex_lock(&stm->policy_mutex);
<------>if (stm->policy)
<------><------>stp_policy_unbind(stm->policy);
<------>mutex_unlock(&stm->policy_mutex);
 
<------>for (i = stm->data->sw_start; i <= stm->data->sw_end; i++)
<------><------>stp_master_free(stm, i);
 
<------>device_unregister(&stm->dev);
<------>stm_data->stm = NULL;
}
EXPORT_SYMBOL_GPL(stm_unregister_device);
 
/*
 * stm::link_list access serialization uses a spinlock and a mutex; holding
 * either of them guarantees that the list is stable; modification requires
 * holding both of them.
 *
 * Lock ordering is as follows:
 *   stm::link_mutex
 *     stm::link_lock
 *       src::link_lock
 */
 
/**
 * stm_source_link_add() - connect an stm_source device to an stm device
 * @src:	stm_source device
 * @stm:	stm device
 *
 * This function establishes a link from stm_source to an stm device so that
 * the former can send out trace data to the latter.
 *
 * Return:	0 on success, -errno otherwise.
 */
static int stm_source_link_add(struct stm_source_device *src,
<------><------><------>       struct stm_device *stm)
{
<------>char *ids[] = { NULL, "default", NULL };
<------>int err = -ENOMEM;
 
<------>mutex_lock(&stm->link_mutex);
<------>spin_lock(&stm->link_lock);
<------>spin_lock(&src->link_lock);
 
<------>/* src->link is dereferenced under stm_source_srcu but not the list */
<------>rcu_assign_pointer(src->link, stm);
<------>list_add_tail(&src->link_entry, &stm->link_list);
 
<------>spin_unlock(&src->link_lock);
<------>spin_unlock(&stm->link_lock);
<------>mutex_unlock(&stm->link_mutex);
 
<------>ids[0] = kstrdup(src->data->name, GFP_KERNEL);
<------>if (!ids[0])
<------><------>goto fail_detach;
 
<------>err = stm_assign_first_policy(stm, &src->output, ids,
<------><------><------><------>      src->data->nr_chans);
<------>kfree(ids[0]);
 
<------>if (err)
<------><------>goto fail_detach;
 
<------>/* this is to notify the STM device that a new link has been made */
<------>if (stm->data->link)
<------><------>err = stm->data->link(stm->data, src->output.master,
<------><------><------><------>      src->output.channel);
 
<------>if (err)
<------><------>goto fail_free_output;
 
<------>/* this is to let the source carry out all necessary preparations */
<------>if (src->data->link)
<------><------>src->data->link(src->data);
 
<------>return 0;
 
fail_free_output:
<------>stm_output_free(stm, &src->output);
 
fail_detach:
<------>mutex_lock(&stm->link_mutex);
<------>spin_lock(&stm->link_lock);
<------>spin_lock(&src->link_lock);
 
<------>rcu_assign_pointer(src->link, NULL);
<------>list_del_init(&src->link_entry);
 
<------>spin_unlock(&src->link_lock);
<------>spin_unlock(&stm->link_lock);
<------>mutex_unlock(&stm->link_mutex);
 
<------>return err;
}
 
/**
 * __stm_source_link_drop() - detach stm_source from an stm device
 * @src:	stm_source device
 * @stm:	stm device
 *
 * If @stm is @src::link, disconnect them from one another and put the
 * reference on the @stm device.
 *
 * Caller must hold stm::link_mutex.
 */
static int __stm_source_link_drop(struct stm_source_device *src,
<------><------><------><------>  struct stm_device *stm)
{
<------>struct stm_device *link;
<------>int ret = 0;
 
<------>lockdep_assert_held(&stm->link_mutex);
 
<------>/* for stm::link_list modification, we hold both mutex and spinlock */
<------>spin_lock(&stm->link_lock);
<------>spin_lock(&src->link_lock);
<------>link = srcu_dereference_check(src->link, &stm_source_srcu, 1);
 
<------>/*
<------> * The linked device may have changed since we last looked, because
<------> * we weren't holding the src::link_lock back then; if this is the
<------> * case, tell the caller to retry.
<------> */
<------>if (link != stm) {
<------><------>ret = -EAGAIN;
<------><------>goto unlock;
<------>}
 
<------>stm_output_free(link, &src->output);
<------>list_del_init(&src->link_entry);
<------>pm_runtime_mark_last_busy(&link->dev);
<------>pm_runtime_put_autosuspend(&link->dev);
<------>/* matches stm_find_device() from stm_source_link_store() */
<------>stm_put_device(link);
<------>rcu_assign_pointer(src->link, NULL);
 
unlock:
<------>spin_unlock(&src->link_lock);
<------>spin_unlock(&stm->link_lock);
 
<------>/*
<------> * Call the unlink callbacks for both source and stm, when we know
<------> * that we have actually performed the unlinking.
<------> */
<------>if (!ret) {
<------><------>if (src->data->unlink)
<------><------><------>src->data->unlink(src->data);
 
<------><------>if (stm->data->unlink)
<------><------><------>stm->data->unlink(stm->data, src->output.master,
<------><------><------><------><------>  src->output.channel);
<------>}
 
<------>return ret;
}
 
/**
 * stm_source_link_drop() - detach stm_source from its stm device
 * @src:	stm_source device
 *
 * Unlinking means disconnecting from source's STM device; after this
 * writes will be unsuccessful until it is linked to a new STM device.
 *
 * This will happen on "stm_source_link" sysfs attribute write to undo
 * the existing link (if any), or on linked STM device's de-registration.
 */
static void stm_source_link_drop(struct stm_source_device *src)
{
<------>struct stm_device *stm;
<------>int idx, ret;
 
retry:
<------>idx = srcu_read_lock(&stm_source_srcu);
<------>/*
<------> * The stm device will be valid for the duration of this
<------> * read section, but the link may change before we grab
<------> * the src::link_lock in __stm_source_link_drop().
<------> */
<------>stm = srcu_dereference(src->link, &stm_source_srcu);
 
<------>ret = 0;
<------>if (stm) {
<------><------>mutex_lock(&stm->link_mutex);
<------><------>ret = __stm_source_link_drop(src, stm);
<------><------>mutex_unlock(&stm->link_mutex);
<------>}
 
<------>srcu_read_unlock(&stm_source_srcu, idx);
 
<------>/* if it did change, retry */
<------>if (ret == -EAGAIN)
<------><------>goto retry;
}
 
static ssize_t stm_source_link_show(struct device *dev,
<------><------><------><------>    struct device_attribute *attr,
<------><------><------><------>    char *buf)
{
<------>struct stm_source_device *src = to_stm_source_device(dev);
<------>struct stm_device *stm;
<------>int idx, ret;
 
<------>idx = srcu_read_lock(&stm_source_srcu);
<------>stm = srcu_dereference(src->link, &stm_source_srcu);
<------>ret = sprintf(buf, "%s\n",
<------><------>      stm ? dev_name(&stm->dev) : "<none>");
<------>srcu_read_unlock(&stm_source_srcu, idx);
 
<------>return ret;
}
 
static ssize_t stm_source_link_store(struct device *dev,
<------><------><------><------>     struct device_attribute *attr,
<------><------><------><------>     const char *buf, size_t count)
{
<------>struct stm_source_device *src = to_stm_source_device(dev);
<------>struct stm_device *link;
<------>int err;
 
<------>stm_source_link_drop(src);
 
<------>link = stm_find_device(buf);
<------>if (!link)
<------><------>return -EINVAL;
 
<------>pm_runtime_get(&link->dev);
 
<------>err = stm_source_link_add(src, link);
<------>if (err) {
<------><------>pm_runtime_put_autosuspend(&link->dev);
<------><------>/* matches the stm_find_device() above */
<------><------>stm_put_device(link);
<------>}
 
<------>return err ? : count;
}
 
static DEVICE_ATTR_RW(stm_source_link);
 
static struct attribute *stm_source_attrs[] = {
<------>&dev_attr_stm_source_link.attr,
<------>NULL,
};
 
ATTRIBUTE_GROUPS(stm_source);
 
static struct class stm_source_class = {
<------>.name		= "stm_source",
<------>.dev_groups	= stm_source_groups,
};
 
static void stm_source_device_release(struct device *dev)
{
<------>struct stm_source_device *src = to_stm_source_device(dev);
 
<------>kfree(src);
}
 
/**
 * stm_source_register_device() - register an stm_source device
 * @parent:	parent device
 * @data:	device description structure
 *
 * This will create a device of stm_source class that can write
 * data to an stm device once linked.
 *
 * Return:	0 on success, -errno otherwise.
 */
int stm_source_register_device(struct device *parent,
<------><------><------>       struct stm_source_data *data)
{
<------>struct stm_source_device *src;
<------>int err;
 
<------>if (!stm_core_up)
<------><------>return -EPROBE_DEFER;
 
<------>src = kzalloc(sizeof(*src), GFP_KERNEL);
<------>if (!src)
<------><------>return -ENOMEM;
 
<------>device_initialize(&src->dev);
<------>src->dev.class = &stm_source_class;
<------>src->dev.parent = parent;
<------>src->dev.release = stm_source_device_release;
 
<------>err = kobject_set_name(&src->dev.kobj, "%s", data->name);
<------>if (err)
<------><------>goto err;
 
<------>pm_runtime_no_callbacks(&src->dev);
<------>pm_runtime_forbid(&src->dev);
 
<------>err = device_add(&src->dev);
<------>if (err)
<------><------>goto err;
 
<------>stm_output_init(&src->output);
<------>spin_lock_init(&src->link_lock);
<------>INIT_LIST_HEAD(&src->link_entry);
<------>src->data = data;
<------>data->src = src;
 
<------>return 0;
 
err:
<------>put_device(&src->dev);
 
<------>return err;
}
EXPORT_SYMBOL_GPL(stm_source_register_device);
 
/**
 * stm_source_unregister_device() - unregister an stm_source device
 * @data:	device description that was used to register the device
 *
 * This will remove a previously created stm_source device from the system.
 */
void stm_source_unregister_device(struct stm_source_data *data)
{
<------>struct stm_source_device *src = data->src;
 
<------>stm_source_link_drop(src);
 
<------>device_unregister(&src->dev);
}
EXPORT_SYMBOL_GPL(stm_source_unregister_device);
 
int notrace stm_source_write(struct stm_source_data *data,
<------><------><------>     unsigned int chan,
<------><------><------>     const char *buf, size_t count)
{
<------>struct stm_source_device *src = data->src;
<------>struct stm_device *stm;
<------>int idx;
 
<------>if (!src->output.nr_chans)
<------><------>return -ENODEV;
 
<------>if (chan >= src->output.nr_chans)
<------><------>return -EINVAL;
 
<------>idx = srcu_read_lock(&stm_source_srcu);
 
<------>stm = srcu_dereference(src->link, &stm_source_srcu);
<------>if (stm)
<------><------>count = stm_write(stm, &src->output, chan, buf, count);
<------>else
<------><------>count = -ENODEV;
 
<------>srcu_read_unlock(&stm_source_srcu, idx);
 
<------>return count;
}
EXPORT_SYMBOL_GPL(stm_source_write);
 
static int __init stm_core_init(void)
{
<------>int err;
 
<------>err = class_register(&stm_class);
<------>if (err)
<------><------>return err;
 
<------>err = class_register(&stm_source_class);
<------>if (err)
<------><------>goto err_stm;
 
<------>err = stp_configfs_init();
<------>if (err)
<------><------>goto err_src;
 
<------>init_srcu_struct(&stm_source_srcu);
<------>INIT_LIST_HEAD(&stm_pdrv_head);
<------>mutex_init(&stm_pdrv_mutex);
 
<------>/*
<------> * So as to not confuse existing users with a requirement
<------> * to load yet another module, do it here.
<------> */
<------>if (IS_ENABLED(CONFIG_STM_PROTO_BASIC))
<------><------>(void)request_module_nowait("stm_p_basic");
<------>stm_core_up++;
 
<------>return 0;
 
err_src:
<------>class_unregister(&stm_source_class);
err_stm:
<------>class_unregister(&stm_class);
 
<------>return err;
}
 
module_init(stm_core_init);
 
static void __exit stm_core_exit(void)
{
<------>cleanup_srcu_struct(&stm_source_srcu);
<------>class_unregister(&stm_source_class);
<------>class_unregister(&stm_class);
<------>stp_configfs_exit();
}
 
module_exit(stm_core_exit);
 
MODULE_LICENSE("GPL v2");
MODULE_DESCRIPTION("System Trace Module device class");
MODULE_AUTHOR("Alexander Shishkin <alexander.shishkin@linux.intel.com>");