diff options
Diffstat (limited to 'kernel/drivers/hwtracing/stm')
| -rw-r--r-- | kernel/drivers/hwtracing/stm/Kconfig | 26 | ||||
| -rw-r--r-- | kernel/drivers/hwtracing/stm/Makefile | 9 | ||||
| -rw-r--r-- | kernel/drivers/hwtracing/stm/console.c | 80 | ||||
| -rw-r--r-- | kernel/drivers/hwtracing/stm/core.c | 1032 | ||||
| -rw-r--r-- | kernel/drivers/hwtracing/stm/dummy_stm.c | 66 | ||||
| -rw-r--r-- | kernel/drivers/hwtracing/stm/policy.c | 472 | ||||
| -rw-r--r-- | kernel/drivers/hwtracing/stm/stm.h | 87 |
7 files changed, 1772 insertions, 0 deletions
diff --git a/kernel/drivers/hwtracing/stm/Kconfig b/kernel/drivers/hwtracing/stm/Kconfig new file mode 100644 index 000000000..83e9f591a --- /dev/null +++ b/kernel/drivers/hwtracing/stm/Kconfig @@ -0,0 +1,26 @@ +config STM + tristate "System Trace Module devices" + select CONFIGFS_FS + help + A System Trace Module (STM) is a device exporting data in System + Trace Protocol (STP) format as defined by MIPI STP standards. + Examples of such devices are Intel(R) Trace Hub and Coresight STM. + + Say Y here to enable System Trace Module device support. + +config STM_DUMMY + tristate "Dummy STM driver" + help + This is a simple dummy device that pretends to be an stm device + and discards your data. Use for stm class testing. + + If you don't know what this is, say N. + +config STM_SOURCE_CONSOLE + tristate "Kernel console over STM devices" + help + This is a kernel space trace source that sends kernel log + messages to trace hosts over STM devices. + + If you want to send kernel console messages over STM devices, + say Y. diff --git a/kernel/drivers/hwtracing/stm/Makefile b/kernel/drivers/hwtracing/stm/Makefile new file mode 100644 index 000000000..f9312c38d --- /dev/null +++ b/kernel/drivers/hwtracing/stm/Makefile @@ -0,0 +1,9 @@ +obj-$(CONFIG_STM) += stm_core.o + +stm_core-y := core.o policy.o + +obj-$(CONFIG_STM_DUMMY) += dummy_stm.o + +obj-$(CONFIG_STM_SOURCE_CONSOLE) += stm_console.o + +stm_console-y := console.o diff --git a/kernel/drivers/hwtracing/stm/console.c b/kernel/drivers/hwtracing/stm/console.c new file mode 100644 index 000000000..c9d9a8d2f --- /dev/null +++ b/kernel/drivers/hwtracing/stm/console.c @@ -0,0 +1,80 @@ +/* + * Simple kernel console driver for STM devices + * Copyright (c) 2014, Intel Corporation. + * + * This program is free software; you can redistribute it and/or modify it + * under the terms and conditions of the GNU General Public License, + * version 2, as published by the Free Software Foundation. + * + * This program is distributed in the hope it will be useful, but WITHOUT + * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or + * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for + * more details. + * + * STM console will send kernel messages over STM devices to a trace host. + */ + +#include <linux/kernel.h> +#include <linux/module.h> +#include <linux/console.h> +#include <linux/slab.h> +#include <linux/stm.h> + +static int stm_console_link(struct stm_source_data *data); +static void stm_console_unlink(struct stm_source_data *data); + +static struct stm_console { + struct stm_source_data data; + struct console console; +} stm_console = { + .data = { + .name = "console", + .nr_chans = 1, + .link = stm_console_link, + .unlink = stm_console_unlink, + }, +}; + +static void +stm_console_write(struct console *con, const char *buf, unsigned len) +{ + struct stm_console *sc = container_of(con, struct stm_console, console); + + stm_source_write(&sc->data, 0, buf, len); +} + +static int stm_console_link(struct stm_source_data *data) +{ + struct stm_console *sc = container_of(data, struct stm_console, data); + + strcpy(sc->console.name, "stm_console"); + sc->console.write = stm_console_write; + sc->console.flags = CON_ENABLED | CON_PRINTBUFFER; + register_console(&sc->console); + + return 0; +} + +static void stm_console_unlink(struct stm_source_data *data) +{ + struct stm_console *sc = container_of(data, struct stm_console, data); + + unregister_console(&sc->console); +} + +static int stm_console_init(void) +{ + return stm_source_register_device(NULL, &stm_console.data); +} + +static void stm_console_exit(void) +{ + stm_source_unregister_device(&stm_console.data); +} + +module_init(stm_console_init); +module_exit(stm_console_exit); + +MODULE_LICENSE("GPL v2"); +MODULE_DESCRIPTION("stm_console driver"); +MODULE_AUTHOR("Alexander Shishkin <alexander.shishkin@linux.intel.com>"); diff --git a/kernel/drivers/hwtracing/stm/core.c b/kernel/drivers/hwtracing/stm/core.c new file mode 100644 index 000000000..b6445d9e5 --- /dev/null +++ b/kernel/drivers/hwtracing/stm/core.c @@ -0,0 +1,1032 @@ +/* + * System Trace Module (STM) infrastructure + * Copyright (c) 2014, Intel Corporation. + * + * This program is free software; you can redistribute it and/or modify it + * under the terms and conditions of the GNU General Public License, + * version 2, as published by the Free Software Foundation. + * + * This program is distributed in the hope it will be useful, but WITHOUT + * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or + * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for + * more details. + * + * STM class implements generic infrastructure for System Trace Module devices + * as defined in MIPI STPv2 specification. + */ + +#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 "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 struct attribute *stm_attrs[] = { + &dev_attr_masters.attr, + &dev_attr_channels.attr, + NULL, +}; + +ATTRIBUTE_GROUPS(stm); + +static struct class stm_class = { + .name = "stm", + .dev_groups = stm_groups, +}; + +static int stm_dev_match(struct device *dev, const void *data) +{ + const char *name = data; + + return sysfs_streq(name, dev_name(dev)); +} + +/** + * 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(&stm_class, NULL, buf, stm_dev_match); + if (!dev) + return NULL; + + stm = to_stm_device(dev); + if (!try_module_get(stm->owner)) { + 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(). + */ +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; + size_t size; + + size = ALIGN(stm->data->sw_nchannels, 8) / 8; + size += sizeof(struct stp_master); + master = kzalloc(size, 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); + + 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); + + bitmap_release_region(&master->chan_map[0], output->channel, + ilog2(output->nr_chans)); + + output->nr_chans = 0; + master->nr_free += output->nr_chans; +} + +/* + * 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; + } + + return -1; +} + +static unsigned 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; + + if (policy_node) { + stp_policy_node_get_ranges(policy_node, + &midx, &mend, &cidx, &cend); + } else { + midx = stm->data->sw_start; + cidx = 0; + mend = stm->data->sw_end; + cend = stm->data->sw_nchannels - 1; + } + + spin_lock(&stm->mc_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) + goto unlock; + + output->master = midx; + output->channel = cidx; + output->nr_chans = width; + stm_output_claim(stm, output); + dev_dbg(&stm->dev, "assigned %u:%u (+%u)\n", midx, cidx, width); + + ret = 0; +unlock: + 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); + if (output->nr_chans) + stm_output_disclaim(stm, output); + spin_unlock(&stm->mc_lock); +} + +static int major_match(struct device *dev, const void *data) +{ + unsigned int major = *(unsigned int *)data; + + return MAJOR(dev->devt) == major; +} + +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 = -ENODEV; + + dev = class_find_device(&stm_class, NULL, &major, major_match); + if (!dev) + return -ENODEV; + + stmf = kzalloc(sizeof(*stmf), GFP_KERNEL); + if (!stmf) + return -ENOMEM; + + 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); + + return err; +} + +static int stm_char_release(struct inode *inode, struct file *file) +{ + struct stm_file *stmf = file->private_data; + + stm_output_free(stmf->stm, &stmf->output); + stm_put_device(stmf->stm); + kfree(stmf); + + return 0; +} + +static int stm_file_assign(struct stm_file *stmf, char *id, unsigned int width) +{ + struct stm_device *stm = stmf->stm; + int ret; + + stmf->policy_node = stp_policy_node_lookup(stm, id); + + ret = stm_output_assign(stm, width, stmf->policy_node, &stmf->output); + + if (stmf->policy_node) + stp_policy_node_put(stmf->policy_node); + + return ret; +} + +static void stm_write(struct stm_data *data, unsigned int master, + unsigned int channel, const char *buf, size_t count) +{ + unsigned int flags = STP_PACKET_TIMESTAMPED; + const unsigned char *p = buf, nil = 0; + size_t pos; + ssize_t sz; + + for (pos = 0, p = buf; count > pos; pos += sz, p += sz) { + sz = min_t(unsigned int, count - pos, 8); + sz = data->packet(data, master, channel, STP_PACKET_DATA, flags, + sz, p); + flags = 0; + } + + data->packet(data, master, channel, STP_PACKET_FLAG, 0, 0, &nil); +} + +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 no m/c have been assigned to this writer up to this + * point, use "default" policy entry + */ + if (!stmf->output.nr_chans) { + err = stm_file_assign(stmf, "default", 1); + /* + * EBUSY means that somebody else just assigned this + * output, which is just fine for write() + */ + if (err && err != -EBUSY) + 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; + } + + stm_write(stm->data, stmf->output.master, stmf->output.channel, kbuf, + count); + + kfree(kbuf); + + return count; +} + +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; + + vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot); + vma->vm_flags |= VM_IO | VM_DONTEXPAND | VM_DONTDUMP; + 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; + int ret = -EINVAL; + u32 size; + + if (stmf->output.nr_chans) + return -EBUSY; + + if (copy_from_user(&size, arg, sizeof(size))) + return -EFAULT; + + if (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 (id->width < 1 || + id->width > PAGE_SIZE / stm->data->sw_mmiosz) + goto err_free; + + ret = stm_file_assign(stmf, id->id, id->width); + if (ret) + goto err_free; + + ret = 0; + + 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); + stm_put_device(stmf->stm); + } + +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; +} + +#ifdef CONFIG_COMPAT +static long +stm_char_compat_ioctl(struct file *file, unsigned int cmd, unsigned long arg) +{ + return stm_char_ioctl(file, cmd, (unsigned long)compat_ptr(arg)); +} +#else +#define stm_char_compat_ioctl NULL +#endif + +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 = stm_char_compat_ioctl, + .llseek = no_llseek, +}; + +static void stm_device_release(struct device *dev) +{ + struct stm_device *stm = to_stm_device(dev); + + kfree(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; + stm = kzalloc(sizeof(*stm) + nmasters * sizeof(void *), GFP_KERNEL); + 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; + + 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; + + spin_lock_init(&stm->link_lock); + INIT_LIST_HEAD(&stm->link_list); + + 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; + + return 0; + +err_device: + put_device(&stm->dev); +err_free: + kfree(stm); + + return err; +} +EXPORT_SYMBOL_GPL(stm_register_device); + +static void __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; + + spin_lock(&stm->link_lock); + list_for_each_entry_safe(src, iter, &stm->link_list, link_entry) { + __stm_source_link_drop(src, stm); + } + spin_unlock(&stm->link_lock); + + 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 = 0; i < stm->sw_nmasters; i++) + stp_master_free(stm, i); + + device_unregister(&stm->dev); + stm_data->stm = NULL; +} +EXPORT_SYMBOL_GPL(stm_unregister_device); + +/** + * 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 *id; + int err; + + 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); + + id = kstrdup(src->data->name, GFP_KERNEL); + if (id) { + src->policy_node = + stp_policy_node_lookup(stm, id); + + kfree(id); + } + + err = stm_output_assign(stm, src->data->nr_chans, + src->policy_node, &src->output); + + if (src->policy_node) + stp_policy_node_put(src->policy_node); + + 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); + stm_put_device(stm); + +fail_detach: + 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); + + 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_lock. + */ +static void __stm_source_link_drop(struct stm_source_device *src, + struct stm_device *stm) +{ + struct stm_device *link; + + spin_lock(&src->link_lock); + link = srcu_dereference_check(src->link, &stm_source_srcu, 1); + if (WARN_ON_ONCE(link != stm)) { + spin_unlock(&src->link_lock); + return; + } + + stm_output_free(link, &src->output); + /* caller must hold stm::link_lock */ + list_del_init(&src->link_entry); + /* matches stm_find_device() from stm_source_link_store() */ + stm_put_device(link); + rcu_assign_pointer(src->link, NULL); + + spin_unlock(&src->link_lock); +} + +/** + * 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; + + idx = srcu_read_lock(&stm_source_srcu); + stm = srcu_dereference(src->link, &stm_source_srcu); + + if (stm) { + if (src->data->unlink) + src->data->unlink(src->data); + + spin_lock(&stm->link_lock); + __stm_source_link_drop(src, stm); + spin_unlock(&stm->link_lock); + } + + srcu_read_unlock(&stm_source_srcu, idx); +} + +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; + + err = stm_source_link_add(src, link); + if (err) + 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; + + err = device_add(&src->dev); + if (err) + goto err; + + 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); + kfree(src); + + 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_destroy(&stm_source_class, src->dev.devt); +} +EXPORT_SYMBOL_GPL(stm_source_unregister_device); + +int 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) + stm_write(stm->data, src->output.master, + src->output.channel + 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); + + 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>"); diff --git a/kernel/drivers/hwtracing/stm/dummy_stm.c b/kernel/drivers/hwtracing/stm/dummy_stm.c new file mode 100644 index 000000000..3709bef0b --- /dev/null +++ b/kernel/drivers/hwtracing/stm/dummy_stm.c @@ -0,0 +1,66 @@ +/* + * A dummy STM device for stm/stm_source class testing. + * Copyright (c) 2014, Intel Corporation. + * + * This program is free software; you can redistribute it and/or modify it + * under the terms and conditions of the GNU General Public License, + * version 2, as published by the Free Software Foundation. + * + * This program is distributed in the hope it will be useful, but WITHOUT + * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or + * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for + * more details. + * + * STM class implements generic infrastructure for System Trace Module devices + * as defined in MIPI STPv2 specification. + */ + +#undef DEBUG +#include <linux/kernel.h> +#include <linux/module.h> +#include <linux/slab.h> +#include <linux/stm.h> + +static ssize_t +dummy_stm_packet(struct stm_data *stm_data, unsigned int master, + unsigned int channel, unsigned int packet, unsigned int flags, + unsigned int size, const unsigned char *payload) +{ +#ifdef DEBUG + u64 pl = 0; + + if (payload) + pl = *(u64 *)payload; + + if (size < 8) + pl &= (1ull << (size * 8)) - 1; + trace_printk("[%u:%u] [pkt: %x/%x] (%llx)\n", master, channel, + packet, size, pl); +#endif + return size; +} + +static struct stm_data dummy_stm = { + .name = "dummy_stm", + .sw_start = 0x0000, + .sw_end = 0xffff, + .sw_nchannels = 0xffff, + .packet = dummy_stm_packet, +}; + +static int dummy_stm_init(void) +{ + return stm_register_device(NULL, &dummy_stm, THIS_MODULE); +} + +static void dummy_stm_exit(void) +{ + stm_unregister_device(&dummy_stm); +} + +module_init(dummy_stm_init); +module_exit(dummy_stm_exit); + +MODULE_LICENSE("GPL v2"); +MODULE_DESCRIPTION("dummy_stm device"); +MODULE_AUTHOR("Alexander Shishkin <alexander.shishkin@linux.intel.com>"); diff --git a/kernel/drivers/hwtracing/stm/policy.c b/kernel/drivers/hwtracing/stm/policy.c new file mode 100644 index 000000000..11ab6d01a --- /dev/null +++ b/kernel/drivers/hwtracing/stm/policy.c @@ -0,0 +1,472 @@ +/* + * System Trace Module (STM) master/channel allocation policy management + * Copyright (c) 2014, Intel Corporation. + * + * This program is free software; you can redistribute it and/or modify it + * under the terms and conditions of the GNU General Public License, + * version 2, as published by the Free Software Foundation. + * + * This program is distributed in the hope it will be useful, but WITHOUT + * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or + * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for + * more details. + * + * A master/channel allocation policy allows mapping string identifiers to + * master and channel ranges, where allocation can be done. + */ + +#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt + +#include <linux/types.h> +#include <linux/module.h> +#include <linux/device.h> +#include <linux/configfs.h> +#include <linux/slab.h> +#include <linux/stm.h> +#include "stm.h" + +/* + * STP Master/Channel allocation policy configfs layout. + */ + +struct stp_policy { + struct config_group group; + struct stm_device *stm; +}; + +struct stp_policy_node { + struct config_group group; + struct stp_policy *policy; + unsigned int first_master; + unsigned int last_master; + unsigned int first_channel; + unsigned int last_channel; +}; + +static struct configfs_subsystem stp_policy_subsys; + +void stp_policy_node_get_ranges(struct stp_policy_node *policy_node, + unsigned int *mstart, unsigned int *mend, + unsigned int *cstart, unsigned int *cend) +{ + *mstart = policy_node->first_master; + *mend = policy_node->last_master; + *cstart = policy_node->first_channel; + *cend = policy_node->last_channel; +} + +static inline char *stp_policy_node_name(struct stp_policy_node *policy_node) +{ + return policy_node->group.cg_item.ci_name ? : "<none>"; +} + +static inline struct stp_policy *to_stp_policy(struct config_item *item) +{ + return item ? + container_of(to_config_group(item), struct stp_policy, group) : + NULL; +} + +static inline struct stp_policy_node * +to_stp_policy_node(struct config_item *item) +{ + return item ? + container_of(to_config_group(item), struct stp_policy_node, + group) : + NULL; +} + +static ssize_t +stp_policy_node_masters_show(struct config_item *item, char *page) +{ + struct stp_policy_node *policy_node = to_stp_policy_node(item); + ssize_t count; + + count = sprintf(page, "%u %u\n", policy_node->first_master, + policy_node->last_master); + + return count; +} + +static ssize_t +stp_policy_node_masters_store(struct config_item *item, const char *page, + size_t count) +{ + struct stp_policy_node *policy_node = to_stp_policy_node(item); + unsigned int first, last; + struct stm_device *stm; + char *p = (char *)page; + ssize_t ret = -ENODEV; + + if (sscanf(p, "%u %u", &first, &last) != 2) + return -EINVAL; + + mutex_lock(&stp_policy_subsys.su_mutex); + stm = policy_node->policy->stm; + if (!stm) + goto unlock; + + /* must be within [sw_start..sw_end], which is an inclusive range */ + if (first > INT_MAX || last > INT_MAX || first > last || + first < stm->data->sw_start || + last > stm->data->sw_end) { + ret = -ERANGE; + goto unlock; + } + + ret = count; + policy_node->first_master = first; + policy_node->last_master = last; + +unlock: + mutex_unlock(&stp_policy_subsys.su_mutex); + + return ret; +} + +static ssize_t +stp_policy_node_channels_show(struct config_item *item, char *page) +{ + struct stp_policy_node *policy_node = to_stp_policy_node(item); + ssize_t count; + + count = sprintf(page, "%u %u\n", policy_node->first_channel, + policy_node->last_channel); + + return count; +} + +static ssize_t +stp_policy_node_channels_store(struct config_item *item, const char *page, + size_t count) +{ + struct stp_policy_node *policy_node = to_stp_policy_node(item); + unsigned int first, last; + struct stm_device *stm; + char *p = (char *)page; + ssize_t ret = -ENODEV; + + if (sscanf(p, "%u %u", &first, &last) != 2) + return -EINVAL; + + mutex_lock(&stp_policy_subsys.su_mutex); + stm = policy_node->policy->stm; + if (!stm) + goto unlock; + + if (first > INT_MAX || last > INT_MAX || first > last || + last >= stm->data->sw_nchannels) { + ret = -ERANGE; + goto unlock; + } + + ret = count; + policy_node->first_channel = first; + policy_node->last_channel = last; + +unlock: + mutex_unlock(&stp_policy_subsys.su_mutex); + + return ret; +} + +static void stp_policy_node_release(struct config_item *item) +{ + kfree(to_stp_policy_node(item)); +} + +static struct configfs_item_operations stp_policy_node_item_ops = { + .release = stp_policy_node_release, +}; + +CONFIGFS_ATTR(stp_policy_node_, masters); +CONFIGFS_ATTR(stp_policy_node_, channels); + +static struct configfs_attribute *stp_policy_node_attrs[] = { + &stp_policy_node_attr_masters, + &stp_policy_node_attr_channels, + NULL, +}; + +static struct config_item_type stp_policy_type; +static struct config_item_type stp_policy_node_type; + +static struct config_group * +stp_policy_node_make(struct config_group *group, const char *name) +{ + struct stp_policy_node *policy_node, *parent_node; + struct stp_policy *policy; + + if (group->cg_item.ci_type == &stp_policy_type) { + policy = container_of(group, struct stp_policy, group); + } else { + parent_node = container_of(group, struct stp_policy_node, + group); + policy = parent_node->policy; + } + + if (!policy->stm) + return ERR_PTR(-ENODEV); + + policy_node = kzalloc(sizeof(struct stp_policy_node), GFP_KERNEL); + if (!policy_node) + return ERR_PTR(-ENOMEM); + + config_group_init_type_name(&policy_node->group, name, + &stp_policy_node_type); + + policy_node->policy = policy; + + /* default values for the attributes */ + policy_node->first_master = policy->stm->data->sw_start; + policy_node->last_master = policy->stm->data->sw_end; + policy_node->first_channel = 0; + policy_node->last_channel = policy->stm->data->sw_nchannels - 1; + + return &policy_node->group; +} + +static void +stp_policy_node_drop(struct config_group *group, struct config_item *item) +{ + config_item_put(item); +} + +static struct configfs_group_operations stp_policy_node_group_ops = { + .make_group = stp_policy_node_make, + .drop_item = stp_policy_node_drop, +}; + +static struct config_item_type stp_policy_node_type = { + .ct_item_ops = &stp_policy_node_item_ops, + .ct_group_ops = &stp_policy_node_group_ops, + .ct_attrs = stp_policy_node_attrs, + .ct_owner = THIS_MODULE, +}; + +/* + * Root group: policies. + */ +static ssize_t stp_policy_device_show(struct config_item *item, + char *page) +{ + struct stp_policy *policy = to_stp_policy(item); + ssize_t count; + + count = sprintf(page, "%s\n", + (policy && policy->stm) ? + policy->stm->data->name : + "<none>"); + + return count; +} + +CONFIGFS_ATTR_RO(stp_policy_, device); + +static struct configfs_attribute *stp_policy_attrs[] = { + &stp_policy_attr_device, + NULL, +}; + +void stp_policy_unbind(struct stp_policy *policy) +{ + struct stm_device *stm = policy->stm; + + if (WARN_ON_ONCE(!policy->stm)) + return; + + mutex_lock(&stm->policy_mutex); + stm->policy = NULL; + mutex_unlock(&stm->policy_mutex); + + policy->stm = NULL; + + stm_put_device(stm); +} + +static void stp_policy_release(struct config_item *item) +{ + struct stp_policy *policy = to_stp_policy(item); + + stp_policy_unbind(policy); + kfree(policy); +} + +static struct configfs_item_operations stp_policy_item_ops = { + .release = stp_policy_release, +}; + +static struct configfs_group_operations stp_policy_group_ops = { + .make_group = stp_policy_node_make, +}; + +static struct config_item_type stp_policy_type = { + .ct_item_ops = &stp_policy_item_ops, + .ct_group_ops = &stp_policy_group_ops, + .ct_attrs = stp_policy_attrs, + .ct_owner = THIS_MODULE, +}; + +static struct config_group * +stp_policies_make(struct config_group *group, const char *name) +{ + struct config_group *ret; + struct stm_device *stm; + char *devname, *p; + + devname = kasprintf(GFP_KERNEL, "%s", name); + if (!devname) + return ERR_PTR(-ENOMEM); + + /* + * node must look like <device_name>.<policy_name>, where + * <device_name> is the name of an existing stm device and + * <policy_name> is an arbitrary string + */ + p = strchr(devname, '.'); + if (!p) { + kfree(devname); + return ERR_PTR(-EINVAL); + } + + *p++ = '\0'; + + stm = stm_find_device(devname); + kfree(devname); + + if (!stm) + return ERR_PTR(-ENODEV); + + mutex_lock(&stm->policy_mutex); + if (stm->policy) { + ret = ERR_PTR(-EBUSY); + goto unlock_policy; + } + + stm->policy = kzalloc(sizeof(*stm->policy), GFP_KERNEL); + if (!stm->policy) { + ret = ERR_PTR(-ENOMEM); + goto unlock_policy; + } + + config_group_init_type_name(&stm->policy->group, name, + &stp_policy_type); + stm->policy->stm = stm; + + ret = &stm->policy->group; + +unlock_policy: + mutex_unlock(&stm->policy_mutex); + + if (IS_ERR(ret)) + stm_put_device(stm); + + return ret; +} + +static struct configfs_group_operations stp_policies_group_ops = { + .make_group = stp_policies_make, +}; + +static struct config_item_type stp_policies_type = { + .ct_group_ops = &stp_policies_group_ops, + .ct_owner = THIS_MODULE, +}; + +static struct configfs_subsystem stp_policy_subsys = { + .su_group = { + .cg_item = { + .ci_namebuf = "stp-policy", + .ci_type = &stp_policies_type, + }, + }, +}; + +/* + * Lock the policy mutex from the outside + */ +static struct stp_policy_node * +__stp_policy_node_lookup(struct stp_policy *policy, char *s) +{ + struct stp_policy_node *policy_node, *ret; + struct list_head *head = &policy->group.cg_children; + struct config_item *item; + char *start, *end = s; + + if (list_empty(head)) + return NULL; + + /* return the first entry if everything else fails */ + item = list_entry(head->next, struct config_item, ci_entry); + ret = to_stp_policy_node(item); + +next: + for (;;) { + start = strsep(&end, "/"); + if (!start) + break; + + if (!*start) + continue; + + list_for_each_entry(item, head, ci_entry) { + policy_node = to_stp_policy_node(item); + + if (!strcmp(start, + policy_node->group.cg_item.ci_name)) { + ret = policy_node; + + if (!end) + goto out; + + head = &policy_node->group.cg_children; + goto next; + } + } + break; + } + +out: + return ret; +} + + +struct stp_policy_node * +stp_policy_node_lookup(struct stm_device *stm, char *s) +{ + struct stp_policy_node *policy_node = NULL; + + mutex_lock(&stp_policy_subsys.su_mutex); + + mutex_lock(&stm->policy_mutex); + if (stm->policy) + policy_node = __stp_policy_node_lookup(stm->policy, s); + mutex_unlock(&stm->policy_mutex); + + if (policy_node) + config_item_get(&policy_node->group.cg_item); + mutex_unlock(&stp_policy_subsys.su_mutex); + + return policy_node; +} + +void stp_policy_node_put(struct stp_policy_node *policy_node) +{ + config_item_put(&policy_node->group.cg_item); +} + +int __init stp_configfs_init(void) +{ + int err; + + config_group_init(&stp_policy_subsys.su_group); + mutex_init(&stp_policy_subsys.su_mutex); + err = configfs_register_subsystem(&stp_policy_subsys); + + return err; +} + +void __exit stp_configfs_exit(void) +{ + configfs_unregister_subsystem(&stp_policy_subsys); +} diff --git a/kernel/drivers/hwtracing/stm/stm.h b/kernel/drivers/hwtracing/stm/stm.h new file mode 100644 index 000000000..95ece0292 --- /dev/null +++ b/kernel/drivers/hwtracing/stm/stm.h @@ -0,0 +1,87 @@ +/* + * System Trace Module (STM) infrastructure + * Copyright (c) 2014, Intel Corporation. + * + * This program is free software; you can redistribute it and/or modify it + * under the terms and conditions of the GNU General Public License, + * version 2, as published by the Free Software Foundation. + * + * This program is distributed in the hope it will be useful, but WITHOUT + * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or + * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for + * more details. + * + * STM class implements generic infrastructure for System Trace Module devices + * as defined in MIPI STPv2 specification. + */ + +#ifndef _STM_STM_H_ +#define _STM_STM_H_ + +struct stp_policy; +struct stp_policy_node; + +struct stp_policy_node * +stp_policy_node_lookup(struct stm_device *stm, char *s); +void stp_policy_node_put(struct stp_policy_node *policy_node); +void stp_policy_unbind(struct stp_policy *policy); + +void stp_policy_node_get_ranges(struct stp_policy_node *policy_node, + unsigned int *mstart, unsigned int *mend, + unsigned int *cstart, unsigned int *cend); +int stp_configfs_init(void); +void stp_configfs_exit(void); + +struct stp_master { + unsigned int nr_free; + unsigned long chan_map[0]; +}; + +struct stm_device { + struct device dev; + struct module *owner; + struct stp_policy *policy; + struct mutex policy_mutex; + int major; + unsigned int sw_nmasters; + struct stm_data *data; + spinlock_t link_lock; + struct list_head link_list; + /* master allocation */ + spinlock_t mc_lock; + struct stp_master *masters[0]; +}; + +#define to_stm_device(_d) \ + container_of((_d), struct stm_device, dev) + +struct stm_output { + unsigned int master; + unsigned int channel; + unsigned int nr_chans; +}; + +struct stm_file { + struct stm_device *stm; + struct stp_policy_node *policy_node; + struct stm_output output; +}; + +struct stm_device *stm_find_device(const char *name); +void stm_put_device(struct stm_device *stm); + +struct stm_source_device { + struct device dev; + struct stm_source_data *data; + spinlock_t link_lock; + struct stm_device __rcu *link; + struct list_head link_entry; + /* one output per stm_source device */ + struct stp_policy_node *policy_node; + struct stm_output output; +}; + +#define to_stm_source_device(_d) \ + container_of((_d), struct stm_source_device, dev) + +#endif /* _STM_STM_H_ */ |