17bd1d409SAlexander Shishkin /* 27bd1d409SAlexander Shishkin * System Trace Module (STM) infrastructure 37bd1d409SAlexander Shishkin * Copyright (c) 2014, Intel Corporation. 47bd1d409SAlexander Shishkin * 57bd1d409SAlexander Shishkin * This program is free software; you can redistribute it and/or modify it 67bd1d409SAlexander Shishkin * under the terms and conditions of the GNU General Public License, 77bd1d409SAlexander Shishkin * version 2, as published by the Free Software Foundation. 87bd1d409SAlexander Shishkin * 97bd1d409SAlexander Shishkin * This program is distributed in the hope it will be useful, but WITHOUT 107bd1d409SAlexander Shishkin * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 117bd1d409SAlexander Shishkin * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for 127bd1d409SAlexander Shishkin * more details. 137bd1d409SAlexander Shishkin * 147bd1d409SAlexander Shishkin * STM class implements generic infrastructure for System Trace Module devices 157bd1d409SAlexander Shishkin * as defined in MIPI STPv2 specification. 167bd1d409SAlexander Shishkin */ 177bd1d409SAlexander Shishkin 187bd1d409SAlexander Shishkin #include <linux/uaccess.h> 197bd1d409SAlexander Shishkin #include <linux/kernel.h> 207bd1d409SAlexander Shishkin #include <linux/module.h> 217bd1d409SAlexander Shishkin #include <linux/device.h> 227bd1d409SAlexander Shishkin #include <linux/compat.h> 237bd1d409SAlexander Shishkin #include <linux/kdev_t.h> 247bd1d409SAlexander Shishkin #include <linux/srcu.h> 257bd1d409SAlexander Shishkin #include <linux/slab.h> 267bd1d409SAlexander Shishkin #include <linux/stm.h> 277bd1d409SAlexander Shishkin #include <linux/fs.h> 287bd1d409SAlexander Shishkin #include <linux/mm.h> 297bd1d409SAlexander Shishkin #include "stm.h" 307bd1d409SAlexander Shishkin 317bd1d409SAlexander Shishkin #include <uapi/linux/stm.h> 327bd1d409SAlexander Shishkin 337bd1d409SAlexander Shishkin static unsigned int stm_core_up; 347bd1d409SAlexander Shishkin 357bd1d409SAlexander Shishkin /* 367bd1d409SAlexander Shishkin * The SRCU here makes sure that STM device doesn't disappear from under a 377bd1d409SAlexander Shishkin * stm_source_write() caller, which may want to have as little overhead as 387bd1d409SAlexander Shishkin * possible. 397bd1d409SAlexander Shishkin */ 407bd1d409SAlexander Shishkin static struct srcu_struct stm_source_srcu; 417bd1d409SAlexander Shishkin 427bd1d409SAlexander Shishkin static ssize_t masters_show(struct device *dev, 437bd1d409SAlexander Shishkin struct device_attribute *attr, 447bd1d409SAlexander Shishkin char *buf) 457bd1d409SAlexander Shishkin { 467bd1d409SAlexander Shishkin struct stm_device *stm = to_stm_device(dev); 477bd1d409SAlexander Shishkin int ret; 487bd1d409SAlexander Shishkin 497bd1d409SAlexander Shishkin ret = sprintf(buf, "%u %u\n", stm->data->sw_start, stm->data->sw_end); 507bd1d409SAlexander Shishkin 517bd1d409SAlexander Shishkin return ret; 527bd1d409SAlexander Shishkin } 537bd1d409SAlexander Shishkin 547bd1d409SAlexander Shishkin static DEVICE_ATTR_RO(masters); 557bd1d409SAlexander Shishkin 567bd1d409SAlexander Shishkin static ssize_t channels_show(struct device *dev, 577bd1d409SAlexander Shishkin struct device_attribute *attr, 587bd1d409SAlexander Shishkin char *buf) 597bd1d409SAlexander Shishkin { 607bd1d409SAlexander Shishkin struct stm_device *stm = to_stm_device(dev); 617bd1d409SAlexander Shishkin int ret; 627bd1d409SAlexander Shishkin 637bd1d409SAlexander Shishkin ret = sprintf(buf, "%u\n", stm->data->sw_nchannels); 647bd1d409SAlexander Shishkin 657bd1d409SAlexander Shishkin return ret; 667bd1d409SAlexander Shishkin } 677bd1d409SAlexander Shishkin 687bd1d409SAlexander Shishkin static DEVICE_ATTR_RO(channels); 697bd1d409SAlexander Shishkin 707bd1d409SAlexander Shishkin static struct attribute *stm_attrs[] = { 717bd1d409SAlexander Shishkin &dev_attr_masters.attr, 727bd1d409SAlexander Shishkin &dev_attr_channels.attr, 737bd1d409SAlexander Shishkin NULL, 747bd1d409SAlexander Shishkin }; 757bd1d409SAlexander Shishkin 767bd1d409SAlexander Shishkin ATTRIBUTE_GROUPS(stm); 777bd1d409SAlexander Shishkin 787bd1d409SAlexander Shishkin static struct class stm_class = { 797bd1d409SAlexander Shishkin .name = "stm", 807bd1d409SAlexander Shishkin .dev_groups = stm_groups, 817bd1d409SAlexander Shishkin }; 827bd1d409SAlexander Shishkin 837bd1d409SAlexander Shishkin static int stm_dev_match(struct device *dev, const void *data) 847bd1d409SAlexander Shishkin { 857bd1d409SAlexander Shishkin const char *name = data; 867bd1d409SAlexander Shishkin 877bd1d409SAlexander Shishkin return sysfs_streq(name, dev_name(dev)); 887bd1d409SAlexander Shishkin } 897bd1d409SAlexander Shishkin 907bd1d409SAlexander Shishkin /** 917bd1d409SAlexander Shishkin * stm_find_device() - find stm device by name 927bd1d409SAlexander Shishkin * @buf: character buffer containing the name 937bd1d409SAlexander Shishkin * 947bd1d409SAlexander Shishkin * This is called when either policy gets assigned to an stm device or an 957bd1d409SAlexander Shishkin * stm_source device gets linked to an stm device. 967bd1d409SAlexander Shishkin * 977bd1d409SAlexander Shishkin * This grabs device's reference (get_device()) and module reference, both 987bd1d409SAlexander Shishkin * of which the calling path needs to make sure to drop with stm_put_device(). 997bd1d409SAlexander Shishkin * 1007bd1d409SAlexander Shishkin * Return: stm device pointer or null if lookup failed. 1017bd1d409SAlexander Shishkin */ 1027bd1d409SAlexander Shishkin struct stm_device *stm_find_device(const char *buf) 1037bd1d409SAlexander Shishkin { 1047bd1d409SAlexander Shishkin struct stm_device *stm; 1057bd1d409SAlexander Shishkin struct device *dev; 1067bd1d409SAlexander Shishkin 1077bd1d409SAlexander Shishkin if (!stm_core_up) 1087bd1d409SAlexander Shishkin return NULL; 1097bd1d409SAlexander Shishkin 1107bd1d409SAlexander Shishkin dev = class_find_device(&stm_class, NULL, buf, stm_dev_match); 1117bd1d409SAlexander Shishkin if (!dev) 1127bd1d409SAlexander Shishkin return NULL; 1137bd1d409SAlexander Shishkin 1147bd1d409SAlexander Shishkin stm = to_stm_device(dev); 1157bd1d409SAlexander Shishkin if (!try_module_get(stm->owner)) { 116f7c81c71SAlexander Shishkin /* matches class_find_device() above */ 1177bd1d409SAlexander Shishkin put_device(dev); 1187bd1d409SAlexander Shishkin return NULL; 1197bd1d409SAlexander Shishkin } 1207bd1d409SAlexander Shishkin 1217bd1d409SAlexander Shishkin return stm; 1227bd1d409SAlexander Shishkin } 1237bd1d409SAlexander Shishkin 1247bd1d409SAlexander Shishkin /** 1257bd1d409SAlexander Shishkin * stm_put_device() - drop references on the stm device 1267bd1d409SAlexander Shishkin * @stm: stm device, previously acquired by stm_find_device() 1277bd1d409SAlexander Shishkin * 1287bd1d409SAlexander Shishkin * This drops the module reference and device reference taken by 129f7c81c71SAlexander Shishkin * stm_find_device() or stm_char_open(). 1307bd1d409SAlexander Shishkin */ 1317bd1d409SAlexander Shishkin void stm_put_device(struct stm_device *stm) 1327bd1d409SAlexander Shishkin { 1337bd1d409SAlexander Shishkin module_put(stm->owner); 1347bd1d409SAlexander Shishkin put_device(&stm->dev); 1357bd1d409SAlexander Shishkin } 1367bd1d409SAlexander Shishkin 1377bd1d409SAlexander Shishkin /* 1387bd1d409SAlexander Shishkin * Internally we only care about software-writable masters here, that is the 1397bd1d409SAlexander Shishkin * ones in the range [stm_data->sw_start..stm_data..sw_end], however we need 1407bd1d409SAlexander Shishkin * original master numbers to be visible externally, since they are the ones 1417bd1d409SAlexander Shishkin * that will appear in the STP stream. Thus, the internal bookkeeping uses 1427bd1d409SAlexander Shishkin * $master - stm_data->sw_start to reference master descriptors and such. 1437bd1d409SAlexander Shishkin */ 1447bd1d409SAlexander Shishkin 1457bd1d409SAlexander Shishkin #define __stm_master(_s, _m) \ 1467bd1d409SAlexander Shishkin ((_s)->masters[(_m) - (_s)->data->sw_start]) 1477bd1d409SAlexander Shishkin 1487bd1d409SAlexander Shishkin static inline struct stp_master * 1497bd1d409SAlexander Shishkin stm_master(struct stm_device *stm, unsigned int idx) 1507bd1d409SAlexander Shishkin { 1517bd1d409SAlexander Shishkin if (idx < stm->data->sw_start || idx > stm->data->sw_end) 1527bd1d409SAlexander Shishkin return NULL; 1537bd1d409SAlexander Shishkin 1547bd1d409SAlexander Shishkin return __stm_master(stm, idx); 1557bd1d409SAlexander Shishkin } 1567bd1d409SAlexander Shishkin 1577bd1d409SAlexander Shishkin static int stp_master_alloc(struct stm_device *stm, unsigned int idx) 1587bd1d409SAlexander Shishkin { 1597bd1d409SAlexander Shishkin struct stp_master *master; 1607bd1d409SAlexander Shishkin size_t size; 1617bd1d409SAlexander Shishkin 1627bd1d409SAlexander Shishkin size = ALIGN(stm->data->sw_nchannels, 8) / 8; 1637bd1d409SAlexander Shishkin size += sizeof(struct stp_master); 1647bd1d409SAlexander Shishkin master = kzalloc(size, GFP_ATOMIC); 1657bd1d409SAlexander Shishkin if (!master) 1667bd1d409SAlexander Shishkin return -ENOMEM; 1677bd1d409SAlexander Shishkin 1687bd1d409SAlexander Shishkin master->nr_free = stm->data->sw_nchannels; 1697bd1d409SAlexander Shishkin __stm_master(stm, idx) = master; 1707bd1d409SAlexander Shishkin 1717bd1d409SAlexander Shishkin return 0; 1727bd1d409SAlexander Shishkin } 1737bd1d409SAlexander Shishkin 1747bd1d409SAlexander Shishkin static void stp_master_free(struct stm_device *stm, unsigned int idx) 1757bd1d409SAlexander Shishkin { 1767bd1d409SAlexander Shishkin struct stp_master *master = stm_master(stm, idx); 1777bd1d409SAlexander Shishkin 1787bd1d409SAlexander Shishkin if (!master) 1797bd1d409SAlexander Shishkin return; 1807bd1d409SAlexander Shishkin 1817bd1d409SAlexander Shishkin __stm_master(stm, idx) = NULL; 1827bd1d409SAlexander Shishkin kfree(master); 1837bd1d409SAlexander Shishkin } 1847bd1d409SAlexander Shishkin 1857bd1d409SAlexander Shishkin static void stm_output_claim(struct stm_device *stm, struct stm_output *output) 1867bd1d409SAlexander Shishkin { 1877bd1d409SAlexander Shishkin struct stp_master *master = stm_master(stm, output->master); 1887bd1d409SAlexander Shishkin 189cde4ad83SAlexander Shishkin lockdep_assert_held(&stm->mc_lock); 190cde4ad83SAlexander Shishkin lockdep_assert_held(&output->lock); 191cde4ad83SAlexander Shishkin 1927bd1d409SAlexander Shishkin if (WARN_ON_ONCE(master->nr_free < output->nr_chans)) 1937bd1d409SAlexander Shishkin return; 1947bd1d409SAlexander Shishkin 1957bd1d409SAlexander Shishkin bitmap_allocate_region(&master->chan_map[0], output->channel, 1967bd1d409SAlexander Shishkin ilog2(output->nr_chans)); 1977bd1d409SAlexander Shishkin 1987bd1d409SAlexander Shishkin master->nr_free -= output->nr_chans; 1997bd1d409SAlexander Shishkin } 2007bd1d409SAlexander Shishkin 2017bd1d409SAlexander Shishkin static void 2027bd1d409SAlexander Shishkin stm_output_disclaim(struct stm_device *stm, struct stm_output *output) 2037bd1d409SAlexander Shishkin { 2047bd1d409SAlexander Shishkin struct stp_master *master = stm_master(stm, output->master); 2057bd1d409SAlexander Shishkin 206cde4ad83SAlexander Shishkin lockdep_assert_held(&stm->mc_lock); 207cde4ad83SAlexander Shishkin lockdep_assert_held(&output->lock); 208cde4ad83SAlexander Shishkin 2097bd1d409SAlexander Shishkin bitmap_release_region(&master->chan_map[0], output->channel, 2107bd1d409SAlexander Shishkin ilog2(output->nr_chans)); 2117bd1d409SAlexander Shishkin 2127bd1d409SAlexander Shishkin output->nr_chans = 0; 2137bd1d409SAlexander Shishkin master->nr_free += output->nr_chans; 2147bd1d409SAlexander Shishkin } 2157bd1d409SAlexander Shishkin 2167bd1d409SAlexander Shishkin /* 2177bd1d409SAlexander Shishkin * This is like bitmap_find_free_region(), except it can ignore @start bits 2187bd1d409SAlexander Shishkin * at the beginning. 2197bd1d409SAlexander Shishkin */ 2207bd1d409SAlexander Shishkin static int find_free_channels(unsigned long *bitmap, unsigned int start, 2217bd1d409SAlexander Shishkin unsigned int end, unsigned int width) 2227bd1d409SAlexander Shishkin { 2237bd1d409SAlexander Shishkin unsigned int pos; 2247bd1d409SAlexander Shishkin int i; 2257bd1d409SAlexander Shishkin 2267bd1d409SAlexander Shishkin for (pos = start; pos < end + 1; pos = ALIGN(pos, width)) { 2277bd1d409SAlexander Shishkin pos = find_next_zero_bit(bitmap, end + 1, pos); 2287bd1d409SAlexander Shishkin if (pos + width > end + 1) 2297bd1d409SAlexander Shishkin break; 2307bd1d409SAlexander Shishkin 2317bd1d409SAlexander Shishkin if (pos & (width - 1)) 2327bd1d409SAlexander Shishkin continue; 2337bd1d409SAlexander Shishkin 2347bd1d409SAlexander Shishkin for (i = 1; i < width && !test_bit(pos + i, bitmap); i++) 2357bd1d409SAlexander Shishkin ; 2367bd1d409SAlexander Shishkin if (i == width) 2377bd1d409SAlexander Shishkin return pos; 2387bd1d409SAlexander Shishkin } 2397bd1d409SAlexander Shishkin 2407bd1d409SAlexander Shishkin return -1; 2417bd1d409SAlexander Shishkin } 2427bd1d409SAlexander Shishkin 243f45f40adSLucas Tanure static int 2447bd1d409SAlexander Shishkin stm_find_master_chan(struct stm_device *stm, unsigned int width, 2457bd1d409SAlexander Shishkin unsigned int *mstart, unsigned int mend, 2467bd1d409SAlexander Shishkin unsigned int *cstart, unsigned int cend) 2477bd1d409SAlexander Shishkin { 2487bd1d409SAlexander Shishkin struct stp_master *master; 2497bd1d409SAlexander Shishkin unsigned int midx; 2507bd1d409SAlexander Shishkin int pos, err; 2517bd1d409SAlexander Shishkin 2527bd1d409SAlexander Shishkin for (midx = *mstart; midx <= mend; midx++) { 2537bd1d409SAlexander Shishkin if (!stm_master(stm, midx)) { 2547bd1d409SAlexander Shishkin err = stp_master_alloc(stm, midx); 2557bd1d409SAlexander Shishkin if (err) 2567bd1d409SAlexander Shishkin return err; 2577bd1d409SAlexander Shishkin } 2587bd1d409SAlexander Shishkin 2597bd1d409SAlexander Shishkin master = stm_master(stm, midx); 2607bd1d409SAlexander Shishkin 2617bd1d409SAlexander Shishkin if (!master->nr_free) 2627bd1d409SAlexander Shishkin continue; 2637bd1d409SAlexander Shishkin 2647bd1d409SAlexander Shishkin pos = find_free_channels(master->chan_map, *cstart, cend, 2657bd1d409SAlexander Shishkin width); 2667bd1d409SAlexander Shishkin if (pos < 0) 2677bd1d409SAlexander Shishkin continue; 2687bd1d409SAlexander Shishkin 2697bd1d409SAlexander Shishkin *mstart = midx; 2707bd1d409SAlexander Shishkin *cstart = pos; 2717bd1d409SAlexander Shishkin return 0; 2727bd1d409SAlexander Shishkin } 2737bd1d409SAlexander Shishkin 2747bd1d409SAlexander Shishkin return -ENOSPC; 2757bd1d409SAlexander Shishkin } 2767bd1d409SAlexander Shishkin 2777bd1d409SAlexander Shishkin static int stm_output_assign(struct stm_device *stm, unsigned int width, 2787bd1d409SAlexander Shishkin struct stp_policy_node *policy_node, 2797bd1d409SAlexander Shishkin struct stm_output *output) 2807bd1d409SAlexander Shishkin { 2817bd1d409SAlexander Shishkin unsigned int midx, cidx, mend, cend; 2827bd1d409SAlexander Shishkin int ret = -EINVAL; 2837bd1d409SAlexander Shishkin 2847bd1d409SAlexander Shishkin if (width > stm->data->sw_nchannels) 2857bd1d409SAlexander Shishkin return -EINVAL; 2867bd1d409SAlexander Shishkin 2877bd1d409SAlexander Shishkin if (policy_node) { 2887bd1d409SAlexander Shishkin stp_policy_node_get_ranges(policy_node, 2897bd1d409SAlexander Shishkin &midx, &mend, &cidx, &cend); 2907bd1d409SAlexander Shishkin } else { 2917bd1d409SAlexander Shishkin midx = stm->data->sw_start; 2927bd1d409SAlexander Shishkin cidx = 0; 2937bd1d409SAlexander Shishkin mend = stm->data->sw_end; 2947bd1d409SAlexander Shishkin cend = stm->data->sw_nchannels - 1; 2957bd1d409SAlexander Shishkin } 2967bd1d409SAlexander Shishkin 2977bd1d409SAlexander Shishkin spin_lock(&stm->mc_lock); 298cde4ad83SAlexander Shishkin spin_lock(&output->lock); 2997bd1d409SAlexander Shishkin /* output is already assigned -- shouldn't happen */ 3007bd1d409SAlexander Shishkin if (WARN_ON_ONCE(output->nr_chans)) 3017bd1d409SAlexander Shishkin goto unlock; 3027bd1d409SAlexander Shishkin 3037bd1d409SAlexander Shishkin ret = stm_find_master_chan(stm, width, &midx, mend, &cidx, cend); 304f45f40adSLucas Tanure if (ret < 0) 3057bd1d409SAlexander Shishkin goto unlock; 3067bd1d409SAlexander Shishkin 3077bd1d409SAlexander Shishkin output->master = midx; 3087bd1d409SAlexander Shishkin output->channel = cidx; 3097bd1d409SAlexander Shishkin output->nr_chans = width; 3107bd1d409SAlexander Shishkin stm_output_claim(stm, output); 3117bd1d409SAlexander Shishkin dev_dbg(&stm->dev, "assigned %u:%u (+%u)\n", midx, cidx, width); 3127bd1d409SAlexander Shishkin 3137bd1d409SAlexander Shishkin ret = 0; 3147bd1d409SAlexander Shishkin unlock: 315cde4ad83SAlexander Shishkin spin_unlock(&output->lock); 3167bd1d409SAlexander Shishkin spin_unlock(&stm->mc_lock); 3177bd1d409SAlexander Shishkin 3187bd1d409SAlexander Shishkin return ret; 3197bd1d409SAlexander Shishkin } 3207bd1d409SAlexander Shishkin 3217bd1d409SAlexander Shishkin static void stm_output_free(struct stm_device *stm, struct stm_output *output) 3227bd1d409SAlexander Shishkin { 3237bd1d409SAlexander Shishkin spin_lock(&stm->mc_lock); 324cde4ad83SAlexander Shishkin spin_lock(&output->lock); 3257bd1d409SAlexander Shishkin if (output->nr_chans) 3267bd1d409SAlexander Shishkin stm_output_disclaim(stm, output); 327cde4ad83SAlexander Shishkin spin_unlock(&output->lock); 3287bd1d409SAlexander Shishkin spin_unlock(&stm->mc_lock); 3297bd1d409SAlexander Shishkin } 3307bd1d409SAlexander Shishkin 331cde4ad83SAlexander Shishkin static void stm_output_init(struct stm_output *output) 332cde4ad83SAlexander Shishkin { 333cde4ad83SAlexander Shishkin spin_lock_init(&output->lock); 334cde4ad83SAlexander Shishkin } 335cde4ad83SAlexander Shishkin 3367bd1d409SAlexander Shishkin static int major_match(struct device *dev, const void *data) 3377bd1d409SAlexander Shishkin { 3387bd1d409SAlexander Shishkin unsigned int major = *(unsigned int *)data; 3397bd1d409SAlexander Shishkin 3407bd1d409SAlexander Shishkin return MAJOR(dev->devt) == major; 3417bd1d409SAlexander Shishkin } 3427bd1d409SAlexander Shishkin 3437bd1d409SAlexander Shishkin static int stm_char_open(struct inode *inode, struct file *file) 3447bd1d409SAlexander Shishkin { 3457bd1d409SAlexander Shishkin struct stm_file *stmf; 3467bd1d409SAlexander Shishkin struct device *dev; 3477bd1d409SAlexander Shishkin unsigned int major = imajor(inode); 3487bd1d409SAlexander Shishkin int err = -ENODEV; 3497bd1d409SAlexander Shishkin 3507bd1d409SAlexander Shishkin dev = class_find_device(&stm_class, NULL, &major, major_match); 3517bd1d409SAlexander Shishkin if (!dev) 3527bd1d409SAlexander Shishkin return -ENODEV; 3537bd1d409SAlexander Shishkin 3547bd1d409SAlexander Shishkin stmf = kzalloc(sizeof(*stmf), GFP_KERNEL); 3557bd1d409SAlexander Shishkin if (!stmf) 3567bd1d409SAlexander Shishkin return -ENOMEM; 3577bd1d409SAlexander Shishkin 358cde4ad83SAlexander Shishkin stm_output_init(&stmf->output); 3597bd1d409SAlexander Shishkin stmf->stm = to_stm_device(dev); 3607bd1d409SAlexander Shishkin 3617bd1d409SAlexander Shishkin if (!try_module_get(stmf->stm->owner)) 3627bd1d409SAlexander Shishkin goto err_free; 3637bd1d409SAlexander Shishkin 3647bd1d409SAlexander Shishkin file->private_data = stmf; 3657bd1d409SAlexander Shishkin 3667bd1d409SAlexander Shishkin return nonseekable_open(inode, file); 3677bd1d409SAlexander Shishkin 3687bd1d409SAlexander Shishkin err_free: 369f7c81c71SAlexander Shishkin /* matches class_find_device() above */ 370f7c81c71SAlexander Shishkin put_device(dev); 3717bd1d409SAlexander Shishkin kfree(stmf); 3727bd1d409SAlexander Shishkin 3737bd1d409SAlexander Shishkin return err; 3747bd1d409SAlexander Shishkin } 3757bd1d409SAlexander Shishkin 3767bd1d409SAlexander Shishkin static int stm_char_release(struct inode *inode, struct file *file) 3777bd1d409SAlexander Shishkin { 3787bd1d409SAlexander Shishkin struct stm_file *stmf = file->private_data; 379cc842407SAlexander Shishkin struct stm_device *stm = stmf->stm; 3807bd1d409SAlexander Shishkin 381cc842407SAlexander Shishkin if (stm->data->unlink) 382cc842407SAlexander Shishkin stm->data->unlink(stm->data, stmf->output.master, 383cc842407SAlexander Shishkin stmf->output.channel); 384cc842407SAlexander Shishkin 385cc842407SAlexander Shishkin stm_output_free(stm, &stmf->output); 386f7c81c71SAlexander Shishkin 387f7c81c71SAlexander Shishkin /* 388f7c81c71SAlexander Shishkin * matches the stm_char_open()'s 389f7c81c71SAlexander Shishkin * class_find_device() + try_module_get() 390f7c81c71SAlexander Shishkin */ 391cc842407SAlexander Shishkin stm_put_device(stm); 3927bd1d409SAlexander Shishkin kfree(stmf); 3937bd1d409SAlexander Shishkin 3947bd1d409SAlexander Shishkin return 0; 3957bd1d409SAlexander Shishkin } 3967bd1d409SAlexander Shishkin 3977bd1d409SAlexander Shishkin static int stm_file_assign(struct stm_file *stmf, char *id, unsigned int width) 3987bd1d409SAlexander Shishkin { 3997bd1d409SAlexander Shishkin struct stm_device *stm = stmf->stm; 4007bd1d409SAlexander Shishkin int ret; 4017bd1d409SAlexander Shishkin 4027bd1d409SAlexander Shishkin stmf->policy_node = stp_policy_node_lookup(stm, id); 4037bd1d409SAlexander Shishkin 4047bd1d409SAlexander Shishkin ret = stm_output_assign(stm, width, stmf->policy_node, &stmf->output); 4057bd1d409SAlexander Shishkin 4067bd1d409SAlexander Shishkin if (stmf->policy_node) 4077bd1d409SAlexander Shishkin stp_policy_node_put(stmf->policy_node); 4087bd1d409SAlexander Shishkin 4097bd1d409SAlexander Shishkin return ret; 4107bd1d409SAlexander Shishkin } 4117bd1d409SAlexander Shishkin 412f8560a9bSAlexander Shishkin static ssize_t stm_write(struct stm_data *data, unsigned int master, 4137bd1d409SAlexander Shishkin unsigned int channel, const char *buf, size_t count) 4147bd1d409SAlexander Shishkin { 4157bd1d409SAlexander Shishkin unsigned int flags = STP_PACKET_TIMESTAMPED; 4167bd1d409SAlexander Shishkin const unsigned char *p = buf, nil = 0; 4177bd1d409SAlexander Shishkin size_t pos; 4187bd1d409SAlexander Shishkin ssize_t sz; 4197bd1d409SAlexander Shishkin 4207bd1d409SAlexander Shishkin for (pos = 0, p = buf; count > pos; pos += sz, p += sz) { 4217bd1d409SAlexander Shishkin sz = min_t(unsigned int, count - pos, 8); 4227bd1d409SAlexander Shishkin sz = data->packet(data, master, channel, STP_PACKET_DATA, flags, 4237bd1d409SAlexander Shishkin sz, p); 4247bd1d409SAlexander Shishkin flags = 0; 425f8560a9bSAlexander Shishkin 426f8560a9bSAlexander Shishkin if (sz < 0) 427f8560a9bSAlexander Shishkin break; 4287bd1d409SAlexander Shishkin } 4297bd1d409SAlexander Shishkin 4307bd1d409SAlexander Shishkin data->packet(data, master, channel, STP_PACKET_FLAG, 0, 0, &nil); 431f8560a9bSAlexander Shishkin 432f8560a9bSAlexander Shishkin return pos; 4337bd1d409SAlexander Shishkin } 4347bd1d409SAlexander Shishkin 4357bd1d409SAlexander Shishkin static ssize_t stm_char_write(struct file *file, const char __user *buf, 4367bd1d409SAlexander Shishkin size_t count, loff_t *ppos) 4377bd1d409SAlexander Shishkin { 4387bd1d409SAlexander Shishkin struct stm_file *stmf = file->private_data; 4397bd1d409SAlexander Shishkin struct stm_device *stm = stmf->stm; 4407bd1d409SAlexander Shishkin char *kbuf; 4417bd1d409SAlexander Shishkin int err; 4427bd1d409SAlexander Shishkin 443f08b1826SAlexander Shishkin if (count + 1 > PAGE_SIZE) 444f08b1826SAlexander Shishkin count = PAGE_SIZE - 1; 445f08b1826SAlexander Shishkin 4467bd1d409SAlexander Shishkin /* 4477bd1d409SAlexander Shishkin * if no m/c have been assigned to this writer up to this 4487bd1d409SAlexander Shishkin * point, use "default" policy entry 4497bd1d409SAlexander Shishkin */ 4507bd1d409SAlexander Shishkin if (!stmf->output.nr_chans) { 4517bd1d409SAlexander Shishkin err = stm_file_assign(stmf, "default", 1); 4527bd1d409SAlexander Shishkin /* 4537bd1d409SAlexander Shishkin * EBUSY means that somebody else just assigned this 4547bd1d409SAlexander Shishkin * output, which is just fine for write() 4557bd1d409SAlexander Shishkin */ 4567bd1d409SAlexander Shishkin if (err && err != -EBUSY) 4577bd1d409SAlexander Shishkin return err; 4587bd1d409SAlexander Shishkin } 4597bd1d409SAlexander Shishkin 4607bd1d409SAlexander Shishkin kbuf = kmalloc(count + 1, GFP_KERNEL); 4617bd1d409SAlexander Shishkin if (!kbuf) 4627bd1d409SAlexander Shishkin return -ENOMEM; 4637bd1d409SAlexander Shishkin 4647bd1d409SAlexander Shishkin err = copy_from_user(kbuf, buf, count); 4657bd1d409SAlexander Shishkin if (err) { 4667bd1d409SAlexander Shishkin kfree(kbuf); 4677bd1d409SAlexander Shishkin return -EFAULT; 4687bd1d409SAlexander Shishkin } 4697bd1d409SAlexander Shishkin 470f8560a9bSAlexander Shishkin count = stm_write(stm->data, stmf->output.master, stmf->output.channel, 471f8560a9bSAlexander Shishkin kbuf, count); 4727bd1d409SAlexander Shishkin 4737bd1d409SAlexander Shishkin kfree(kbuf); 4747bd1d409SAlexander Shishkin 4757bd1d409SAlexander Shishkin return count; 4767bd1d409SAlexander Shishkin } 4777bd1d409SAlexander Shishkin 4787bd1d409SAlexander Shishkin static int stm_char_mmap(struct file *file, struct vm_area_struct *vma) 4797bd1d409SAlexander Shishkin { 4807bd1d409SAlexander Shishkin struct stm_file *stmf = file->private_data; 4817bd1d409SAlexander Shishkin struct stm_device *stm = stmf->stm; 4827bd1d409SAlexander Shishkin unsigned long size, phys; 4837bd1d409SAlexander Shishkin 4847bd1d409SAlexander Shishkin if (!stm->data->mmio_addr) 4857bd1d409SAlexander Shishkin return -EOPNOTSUPP; 4867bd1d409SAlexander Shishkin 4877bd1d409SAlexander Shishkin if (vma->vm_pgoff) 4887bd1d409SAlexander Shishkin return -EINVAL; 4897bd1d409SAlexander Shishkin 4907bd1d409SAlexander Shishkin size = vma->vm_end - vma->vm_start; 4917bd1d409SAlexander Shishkin 4927bd1d409SAlexander Shishkin if (stmf->output.nr_chans * stm->data->sw_mmiosz != size) 4937bd1d409SAlexander Shishkin return -EINVAL; 4947bd1d409SAlexander Shishkin 4957bd1d409SAlexander Shishkin phys = stm->data->mmio_addr(stm->data, stmf->output.master, 4967bd1d409SAlexander Shishkin stmf->output.channel, 4977bd1d409SAlexander Shishkin stmf->output.nr_chans); 4987bd1d409SAlexander Shishkin 4997bd1d409SAlexander Shishkin if (!phys) 5007bd1d409SAlexander Shishkin return -EINVAL; 5017bd1d409SAlexander Shishkin 5027bd1d409SAlexander Shishkin vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot); 5037bd1d409SAlexander Shishkin vma->vm_flags |= VM_IO | VM_DONTEXPAND | VM_DONTDUMP; 5047bd1d409SAlexander Shishkin vm_iomap_memory(vma, phys, size); 5057bd1d409SAlexander Shishkin 5067bd1d409SAlexander Shishkin return 0; 5077bd1d409SAlexander Shishkin } 5087bd1d409SAlexander Shishkin 5097bd1d409SAlexander Shishkin static int stm_char_policy_set_ioctl(struct stm_file *stmf, void __user *arg) 5107bd1d409SAlexander Shishkin { 5117bd1d409SAlexander Shishkin struct stm_device *stm = stmf->stm; 5127bd1d409SAlexander Shishkin struct stp_policy_id *id; 5137bd1d409SAlexander Shishkin int ret = -EINVAL; 5147bd1d409SAlexander Shishkin u32 size; 5157bd1d409SAlexander Shishkin 5167bd1d409SAlexander Shishkin if (stmf->output.nr_chans) 5177bd1d409SAlexander Shishkin return -EBUSY; 5187bd1d409SAlexander Shishkin 5197bd1d409SAlexander Shishkin if (copy_from_user(&size, arg, sizeof(size))) 5207bd1d409SAlexander Shishkin return -EFAULT; 5217bd1d409SAlexander Shishkin 5227bd1d409SAlexander Shishkin if (size >= PATH_MAX + sizeof(*id)) 5237bd1d409SAlexander Shishkin return -EINVAL; 5247bd1d409SAlexander Shishkin 5257bd1d409SAlexander Shishkin /* 5267bd1d409SAlexander Shishkin * size + 1 to make sure the .id string at the bottom is terminated, 5277bd1d409SAlexander Shishkin * which is also why memdup_user() is not useful here 5287bd1d409SAlexander Shishkin */ 5297bd1d409SAlexander Shishkin id = kzalloc(size + 1, GFP_KERNEL); 5307bd1d409SAlexander Shishkin if (!id) 5317bd1d409SAlexander Shishkin return -ENOMEM; 5327bd1d409SAlexander Shishkin 5337bd1d409SAlexander Shishkin if (copy_from_user(id, arg, size)) { 5347bd1d409SAlexander Shishkin ret = -EFAULT; 5357bd1d409SAlexander Shishkin goto err_free; 5367bd1d409SAlexander Shishkin } 5377bd1d409SAlexander Shishkin 5387bd1d409SAlexander Shishkin if (id->__reserved_0 || id->__reserved_1) 5397bd1d409SAlexander Shishkin goto err_free; 5407bd1d409SAlexander Shishkin 5417bd1d409SAlexander Shishkin if (id->width < 1 || 5427bd1d409SAlexander Shishkin id->width > PAGE_SIZE / stm->data->sw_mmiosz) 5437bd1d409SAlexander Shishkin goto err_free; 5447bd1d409SAlexander Shishkin 5457bd1d409SAlexander Shishkin ret = stm_file_assign(stmf, id->id, id->width); 5467bd1d409SAlexander Shishkin if (ret) 5477bd1d409SAlexander Shishkin goto err_free; 5487bd1d409SAlexander Shishkin 5497bd1d409SAlexander Shishkin if (stm->data->link) 5507bd1d409SAlexander Shishkin ret = stm->data->link(stm->data, stmf->output.master, 5517bd1d409SAlexander Shishkin stmf->output.channel); 5527bd1d409SAlexander Shishkin 553f7c81c71SAlexander Shishkin if (ret) 5547bd1d409SAlexander Shishkin stm_output_free(stmf->stm, &stmf->output); 5557bd1d409SAlexander Shishkin 5567bd1d409SAlexander Shishkin err_free: 5577bd1d409SAlexander Shishkin kfree(id); 5587bd1d409SAlexander Shishkin 5597bd1d409SAlexander Shishkin return ret; 5607bd1d409SAlexander Shishkin } 5617bd1d409SAlexander Shishkin 5627bd1d409SAlexander Shishkin static int stm_char_policy_get_ioctl(struct stm_file *stmf, void __user *arg) 5637bd1d409SAlexander Shishkin { 5647bd1d409SAlexander Shishkin struct stp_policy_id id = { 5657bd1d409SAlexander Shishkin .size = sizeof(id), 5667bd1d409SAlexander Shishkin .master = stmf->output.master, 5677bd1d409SAlexander Shishkin .channel = stmf->output.channel, 5687bd1d409SAlexander Shishkin .width = stmf->output.nr_chans, 5697bd1d409SAlexander Shishkin .__reserved_0 = 0, 5707bd1d409SAlexander Shishkin .__reserved_1 = 0, 5717bd1d409SAlexander Shishkin }; 5727bd1d409SAlexander Shishkin 5737bd1d409SAlexander Shishkin return copy_to_user(arg, &id, id.size) ? -EFAULT : 0; 5747bd1d409SAlexander Shishkin } 5757bd1d409SAlexander Shishkin 5767bd1d409SAlexander Shishkin static long 5777bd1d409SAlexander Shishkin stm_char_ioctl(struct file *file, unsigned int cmd, unsigned long arg) 5787bd1d409SAlexander Shishkin { 5797bd1d409SAlexander Shishkin struct stm_file *stmf = file->private_data; 5807bd1d409SAlexander Shishkin struct stm_data *stm_data = stmf->stm->data; 5817bd1d409SAlexander Shishkin int err = -ENOTTY; 5827bd1d409SAlexander Shishkin u64 options; 5837bd1d409SAlexander Shishkin 5847bd1d409SAlexander Shishkin switch (cmd) { 5857bd1d409SAlexander Shishkin case STP_POLICY_ID_SET: 5867bd1d409SAlexander Shishkin err = stm_char_policy_set_ioctl(stmf, (void __user *)arg); 5877bd1d409SAlexander Shishkin if (err) 5887bd1d409SAlexander Shishkin return err; 5897bd1d409SAlexander Shishkin 5907bd1d409SAlexander Shishkin return stm_char_policy_get_ioctl(stmf, (void __user *)arg); 5917bd1d409SAlexander Shishkin 5927bd1d409SAlexander Shishkin case STP_POLICY_ID_GET: 5937bd1d409SAlexander Shishkin return stm_char_policy_get_ioctl(stmf, (void __user *)arg); 5947bd1d409SAlexander Shishkin 5957bd1d409SAlexander Shishkin case STP_SET_OPTIONS: 5967bd1d409SAlexander Shishkin if (copy_from_user(&options, (u64 __user *)arg, sizeof(u64))) 5977bd1d409SAlexander Shishkin return -EFAULT; 5987bd1d409SAlexander Shishkin 5997bd1d409SAlexander Shishkin if (stm_data->set_options) 6007bd1d409SAlexander Shishkin err = stm_data->set_options(stm_data, 6017bd1d409SAlexander Shishkin stmf->output.master, 6027bd1d409SAlexander Shishkin stmf->output.channel, 6037bd1d409SAlexander Shishkin stmf->output.nr_chans, 6047bd1d409SAlexander Shishkin options); 6057bd1d409SAlexander Shishkin 6067bd1d409SAlexander Shishkin break; 6077bd1d409SAlexander Shishkin default: 6087bd1d409SAlexander Shishkin break; 6097bd1d409SAlexander Shishkin } 6107bd1d409SAlexander Shishkin 6117bd1d409SAlexander Shishkin return err; 6127bd1d409SAlexander Shishkin } 6137bd1d409SAlexander Shishkin 6147bd1d409SAlexander Shishkin #ifdef CONFIG_COMPAT 6157bd1d409SAlexander Shishkin static long 6167bd1d409SAlexander Shishkin stm_char_compat_ioctl(struct file *file, unsigned int cmd, unsigned long arg) 6177bd1d409SAlexander Shishkin { 6187bd1d409SAlexander Shishkin return stm_char_ioctl(file, cmd, (unsigned long)compat_ptr(arg)); 6197bd1d409SAlexander Shishkin } 6207bd1d409SAlexander Shishkin #else 6217bd1d409SAlexander Shishkin #define stm_char_compat_ioctl NULL 6227bd1d409SAlexander Shishkin #endif 6237bd1d409SAlexander Shishkin 6247bd1d409SAlexander Shishkin static const struct file_operations stm_fops = { 6257bd1d409SAlexander Shishkin .open = stm_char_open, 6267bd1d409SAlexander Shishkin .release = stm_char_release, 6277bd1d409SAlexander Shishkin .write = stm_char_write, 6287bd1d409SAlexander Shishkin .mmap = stm_char_mmap, 6297bd1d409SAlexander Shishkin .unlocked_ioctl = stm_char_ioctl, 6307bd1d409SAlexander Shishkin .compat_ioctl = stm_char_compat_ioctl, 6317bd1d409SAlexander Shishkin .llseek = no_llseek, 6327bd1d409SAlexander Shishkin }; 6337bd1d409SAlexander Shishkin 6347bd1d409SAlexander Shishkin static void stm_device_release(struct device *dev) 6357bd1d409SAlexander Shishkin { 6367bd1d409SAlexander Shishkin struct stm_device *stm = to_stm_device(dev); 6377bd1d409SAlexander Shishkin 6387bd1d409SAlexander Shishkin kfree(stm); 6397bd1d409SAlexander Shishkin } 6407bd1d409SAlexander Shishkin 6417bd1d409SAlexander Shishkin int stm_register_device(struct device *parent, struct stm_data *stm_data, 6427bd1d409SAlexander Shishkin struct module *owner) 6437bd1d409SAlexander Shishkin { 6447bd1d409SAlexander Shishkin struct stm_device *stm; 6457bd1d409SAlexander Shishkin unsigned int nmasters; 6467bd1d409SAlexander Shishkin int err = -ENOMEM; 6477bd1d409SAlexander Shishkin 6487bd1d409SAlexander Shishkin if (!stm_core_up) 6497bd1d409SAlexander Shishkin return -EPROBE_DEFER; 6507bd1d409SAlexander Shishkin 6517bd1d409SAlexander Shishkin if (!stm_data->packet || !stm_data->sw_nchannels) 6527bd1d409SAlexander Shishkin return -EINVAL; 6537bd1d409SAlexander Shishkin 6547b3bb0e7SChunyan Zhang nmasters = stm_data->sw_end - stm_data->sw_start + 1; 6557bd1d409SAlexander Shishkin stm = kzalloc(sizeof(*stm) + nmasters * sizeof(void *), GFP_KERNEL); 6567bd1d409SAlexander Shishkin if (!stm) 6577bd1d409SAlexander Shishkin return -ENOMEM; 6587bd1d409SAlexander Shishkin 6597bd1d409SAlexander Shishkin stm->major = register_chrdev(0, stm_data->name, &stm_fops); 6607bd1d409SAlexander Shishkin if (stm->major < 0) 6617bd1d409SAlexander Shishkin goto err_free; 6627bd1d409SAlexander Shishkin 6637bd1d409SAlexander Shishkin device_initialize(&stm->dev); 6647bd1d409SAlexander Shishkin stm->dev.devt = MKDEV(stm->major, 0); 6657bd1d409SAlexander Shishkin stm->dev.class = &stm_class; 6667bd1d409SAlexander Shishkin stm->dev.parent = parent; 6677bd1d409SAlexander Shishkin stm->dev.release = stm_device_release; 6687bd1d409SAlexander Shishkin 669389b6699SAlexander Shishkin mutex_init(&stm->link_mutex); 670389b6699SAlexander Shishkin spin_lock_init(&stm->link_lock); 671389b6699SAlexander Shishkin INIT_LIST_HEAD(&stm->link_list); 672389b6699SAlexander Shishkin 673389b6699SAlexander Shishkin /* initialize the object before it is accessible via sysfs */ 674389b6699SAlexander Shishkin spin_lock_init(&stm->mc_lock); 675389b6699SAlexander Shishkin mutex_init(&stm->policy_mutex); 676389b6699SAlexander Shishkin stm->sw_nmasters = nmasters; 677389b6699SAlexander Shishkin stm->owner = owner; 678389b6699SAlexander Shishkin stm->data = stm_data; 679389b6699SAlexander Shishkin stm_data->stm = stm; 680389b6699SAlexander Shishkin 6817bd1d409SAlexander Shishkin err = kobject_set_name(&stm->dev.kobj, "%s", stm_data->name); 6827bd1d409SAlexander Shishkin if (err) 6837bd1d409SAlexander Shishkin goto err_device; 6847bd1d409SAlexander Shishkin 6857bd1d409SAlexander Shishkin err = device_add(&stm->dev); 6867bd1d409SAlexander Shishkin if (err) 6877bd1d409SAlexander Shishkin goto err_device; 6887bd1d409SAlexander Shishkin 6897bd1d409SAlexander Shishkin return 0; 6907bd1d409SAlexander Shishkin 6917bd1d409SAlexander Shishkin err_device: 692cbe4a61dSAlexander Shishkin unregister_chrdev(stm->major, stm_data->name); 693cbe4a61dSAlexander Shishkin 694f7c81c71SAlexander Shishkin /* matches device_initialize() above */ 6957bd1d409SAlexander Shishkin put_device(&stm->dev); 6967bd1d409SAlexander Shishkin err_free: 6977bd1d409SAlexander Shishkin kfree(stm); 6987bd1d409SAlexander Shishkin 6997bd1d409SAlexander Shishkin return err; 7007bd1d409SAlexander Shishkin } 7017bd1d409SAlexander Shishkin EXPORT_SYMBOL_GPL(stm_register_device); 7027bd1d409SAlexander Shishkin 703b4ca34aaSAlexander Shishkin static int __stm_source_link_drop(struct stm_source_device *src, 7047bd1d409SAlexander Shishkin struct stm_device *stm); 7057bd1d409SAlexander Shishkin 7067bd1d409SAlexander Shishkin void stm_unregister_device(struct stm_data *stm_data) 7077bd1d409SAlexander Shishkin { 7087bd1d409SAlexander Shishkin struct stm_device *stm = stm_data->stm; 7097bd1d409SAlexander Shishkin struct stm_source_device *src, *iter; 710b4ca34aaSAlexander Shishkin int i, ret; 7117bd1d409SAlexander Shishkin 712c74f7e82SAlexander Shishkin mutex_lock(&stm->link_mutex); 7137bd1d409SAlexander Shishkin list_for_each_entry_safe(src, iter, &stm->link_list, link_entry) { 714b4ca34aaSAlexander Shishkin ret = __stm_source_link_drop(src, stm); 715b4ca34aaSAlexander Shishkin /* 716b4ca34aaSAlexander Shishkin * src <-> stm link must not change under the same 717b4ca34aaSAlexander Shishkin * stm::link_mutex, so complain loudly if it has; 718b4ca34aaSAlexander Shishkin * also in this situation ret!=0 means this src is 719b4ca34aaSAlexander Shishkin * not connected to this stm and it should be otherwise 720b4ca34aaSAlexander Shishkin * safe to proceed with the tear-down of stm. 721b4ca34aaSAlexander Shishkin */ 722b4ca34aaSAlexander Shishkin WARN_ON_ONCE(ret); 7237bd1d409SAlexander Shishkin } 724c74f7e82SAlexander Shishkin mutex_unlock(&stm->link_mutex); 7257bd1d409SAlexander Shishkin 7267bd1d409SAlexander Shishkin synchronize_srcu(&stm_source_srcu); 7277bd1d409SAlexander Shishkin 7287bd1d409SAlexander Shishkin unregister_chrdev(stm->major, stm_data->name); 7297bd1d409SAlexander Shishkin 7307bd1d409SAlexander Shishkin mutex_lock(&stm->policy_mutex); 7317bd1d409SAlexander Shishkin if (stm->policy) 7327bd1d409SAlexander Shishkin stp_policy_unbind(stm->policy); 7337bd1d409SAlexander Shishkin mutex_unlock(&stm->policy_mutex); 7347bd1d409SAlexander Shishkin 73573a3ed19SChunyan Zhang for (i = stm->data->sw_start; i <= stm->data->sw_end; i++) 7367bd1d409SAlexander Shishkin stp_master_free(stm, i); 7377bd1d409SAlexander Shishkin 7387bd1d409SAlexander Shishkin device_unregister(&stm->dev); 7397bd1d409SAlexander Shishkin stm_data->stm = NULL; 7407bd1d409SAlexander Shishkin } 7417bd1d409SAlexander Shishkin EXPORT_SYMBOL_GPL(stm_unregister_device); 7427bd1d409SAlexander Shishkin 743c74f7e82SAlexander Shishkin /* 744c74f7e82SAlexander Shishkin * stm::link_list access serialization uses a spinlock and a mutex; holding 745c74f7e82SAlexander Shishkin * either of them guarantees that the list is stable; modification requires 746c74f7e82SAlexander Shishkin * holding both of them. 747c74f7e82SAlexander Shishkin * 748c74f7e82SAlexander Shishkin * Lock ordering is as follows: 749c74f7e82SAlexander Shishkin * stm::link_mutex 750c74f7e82SAlexander Shishkin * stm::link_lock 751c74f7e82SAlexander Shishkin * src::link_lock 752c74f7e82SAlexander Shishkin */ 753c74f7e82SAlexander Shishkin 7547bd1d409SAlexander Shishkin /** 7557bd1d409SAlexander Shishkin * stm_source_link_add() - connect an stm_source device to an stm device 7567bd1d409SAlexander Shishkin * @src: stm_source device 7577bd1d409SAlexander Shishkin * @stm: stm device 7587bd1d409SAlexander Shishkin * 7597bd1d409SAlexander Shishkin * This function establishes a link from stm_source to an stm device so that 7607bd1d409SAlexander Shishkin * the former can send out trace data to the latter. 7617bd1d409SAlexander Shishkin * 7627bd1d409SAlexander Shishkin * Return: 0 on success, -errno otherwise. 7637bd1d409SAlexander Shishkin */ 7647bd1d409SAlexander Shishkin static int stm_source_link_add(struct stm_source_device *src, 7657bd1d409SAlexander Shishkin struct stm_device *stm) 7667bd1d409SAlexander Shishkin { 7677bd1d409SAlexander Shishkin char *id; 7687bd1d409SAlexander Shishkin int err; 7697bd1d409SAlexander Shishkin 770c74f7e82SAlexander Shishkin mutex_lock(&stm->link_mutex); 7717bd1d409SAlexander Shishkin spin_lock(&stm->link_lock); 7727bd1d409SAlexander Shishkin spin_lock(&src->link_lock); 7737bd1d409SAlexander Shishkin 7747bd1d409SAlexander Shishkin /* src->link is dereferenced under stm_source_srcu but not the list */ 7757bd1d409SAlexander Shishkin rcu_assign_pointer(src->link, stm); 7767bd1d409SAlexander Shishkin list_add_tail(&src->link_entry, &stm->link_list); 7777bd1d409SAlexander Shishkin 7787bd1d409SAlexander Shishkin spin_unlock(&src->link_lock); 7797bd1d409SAlexander Shishkin spin_unlock(&stm->link_lock); 780c74f7e82SAlexander Shishkin mutex_unlock(&stm->link_mutex); 7817bd1d409SAlexander Shishkin 7827bd1d409SAlexander Shishkin id = kstrdup(src->data->name, GFP_KERNEL); 7837bd1d409SAlexander Shishkin if (id) { 7847bd1d409SAlexander Shishkin src->policy_node = 7857bd1d409SAlexander Shishkin stp_policy_node_lookup(stm, id); 7867bd1d409SAlexander Shishkin 7877bd1d409SAlexander Shishkin kfree(id); 7887bd1d409SAlexander Shishkin } 7897bd1d409SAlexander Shishkin 7907bd1d409SAlexander Shishkin err = stm_output_assign(stm, src->data->nr_chans, 7917bd1d409SAlexander Shishkin src->policy_node, &src->output); 7927bd1d409SAlexander Shishkin 7937bd1d409SAlexander Shishkin if (src->policy_node) 7947bd1d409SAlexander Shishkin stp_policy_node_put(src->policy_node); 7957bd1d409SAlexander Shishkin 7967bd1d409SAlexander Shishkin if (err) 7977bd1d409SAlexander Shishkin goto fail_detach; 7987bd1d409SAlexander Shishkin 7997bd1d409SAlexander Shishkin /* this is to notify the STM device that a new link has been made */ 8007bd1d409SAlexander Shishkin if (stm->data->link) 8017bd1d409SAlexander Shishkin err = stm->data->link(stm->data, src->output.master, 8027bd1d409SAlexander Shishkin src->output.channel); 8037bd1d409SAlexander Shishkin 8047bd1d409SAlexander Shishkin if (err) 8057bd1d409SAlexander Shishkin goto fail_free_output; 8067bd1d409SAlexander Shishkin 8077bd1d409SAlexander Shishkin /* this is to let the source carry out all necessary preparations */ 8087bd1d409SAlexander Shishkin if (src->data->link) 8097bd1d409SAlexander Shishkin src->data->link(src->data); 8107bd1d409SAlexander Shishkin 8117bd1d409SAlexander Shishkin return 0; 8127bd1d409SAlexander Shishkin 8137bd1d409SAlexander Shishkin fail_free_output: 8147bd1d409SAlexander Shishkin stm_output_free(stm, &src->output); 8157bd1d409SAlexander Shishkin 8167bd1d409SAlexander Shishkin fail_detach: 817c74f7e82SAlexander Shishkin mutex_lock(&stm->link_mutex); 8187bd1d409SAlexander Shishkin spin_lock(&stm->link_lock); 8197bd1d409SAlexander Shishkin spin_lock(&src->link_lock); 8207bd1d409SAlexander Shishkin 8217bd1d409SAlexander Shishkin rcu_assign_pointer(src->link, NULL); 8227bd1d409SAlexander Shishkin list_del_init(&src->link_entry); 8237bd1d409SAlexander Shishkin 8247bd1d409SAlexander Shishkin spin_unlock(&src->link_lock); 8257bd1d409SAlexander Shishkin spin_unlock(&stm->link_lock); 826c74f7e82SAlexander Shishkin mutex_unlock(&stm->link_mutex); 8277bd1d409SAlexander Shishkin 8287bd1d409SAlexander Shishkin return err; 8297bd1d409SAlexander Shishkin } 8307bd1d409SAlexander Shishkin 8317bd1d409SAlexander Shishkin /** 8327bd1d409SAlexander Shishkin * __stm_source_link_drop() - detach stm_source from an stm device 8337bd1d409SAlexander Shishkin * @src: stm_source device 8347bd1d409SAlexander Shishkin * @stm: stm device 8357bd1d409SAlexander Shishkin * 8367bd1d409SAlexander Shishkin * If @stm is @src::link, disconnect them from one another and put the 8377bd1d409SAlexander Shishkin * reference on the @stm device. 8387bd1d409SAlexander Shishkin * 839c74f7e82SAlexander Shishkin * Caller must hold stm::link_mutex. 8407bd1d409SAlexander Shishkin */ 841b4ca34aaSAlexander Shishkin static int __stm_source_link_drop(struct stm_source_device *src, 8427bd1d409SAlexander Shishkin struct stm_device *stm) 8437bd1d409SAlexander Shishkin { 8440df771deSAlexander Shishkin struct stm_device *link; 845b4ca34aaSAlexander Shishkin int ret = 0; 8460df771deSAlexander Shishkin 847c74f7e82SAlexander Shishkin lockdep_assert_held(&stm->link_mutex); 848c74f7e82SAlexander Shishkin 849c74f7e82SAlexander Shishkin /* for stm::link_list modification, we hold both mutex and spinlock */ 850c74f7e82SAlexander Shishkin spin_lock(&stm->link_lock); 8517bd1d409SAlexander Shishkin spin_lock(&src->link_lock); 8520df771deSAlexander Shishkin link = srcu_dereference_check(src->link, &stm_source_srcu, 1); 853b4ca34aaSAlexander Shishkin 854b4ca34aaSAlexander Shishkin /* 855b4ca34aaSAlexander Shishkin * The linked device may have changed since we last looked, because 856b4ca34aaSAlexander Shishkin * we weren't holding the src::link_lock back then; if this is the 857b4ca34aaSAlexander Shishkin * case, tell the caller to retry. 858b4ca34aaSAlexander Shishkin */ 859b4ca34aaSAlexander Shishkin if (link != stm) { 860b4ca34aaSAlexander Shishkin ret = -EAGAIN; 8611810f2c4SAlexander Shishkin goto unlock; 862b4ca34aaSAlexander Shishkin } 8637bd1d409SAlexander Shishkin 8640df771deSAlexander Shishkin stm_output_free(link, &src->output); 8657bd1d409SAlexander Shishkin list_del_init(&src->link_entry); 8667bd1d409SAlexander Shishkin /* matches stm_find_device() from stm_source_link_store() */ 8670df771deSAlexander Shishkin stm_put_device(link); 8687bd1d409SAlexander Shishkin rcu_assign_pointer(src->link, NULL); 8697bd1d409SAlexander Shishkin 8701810f2c4SAlexander Shishkin unlock: 8717bd1d409SAlexander Shishkin spin_unlock(&src->link_lock); 872c74f7e82SAlexander Shishkin spin_unlock(&stm->link_lock); 873b4ca34aaSAlexander Shishkin 874cc842407SAlexander Shishkin /* 875cc842407SAlexander Shishkin * Call the unlink callbacks for both source and stm, when we know 876cc842407SAlexander Shishkin * that we have actually performed the unlinking. 877cc842407SAlexander Shishkin */ 878cc842407SAlexander Shishkin if (!ret) { 879cc842407SAlexander Shishkin if (src->data->unlink) 880b4ca34aaSAlexander Shishkin src->data->unlink(src->data); 881b4ca34aaSAlexander Shishkin 882cc842407SAlexander Shishkin if (stm->data->unlink) 883cc842407SAlexander Shishkin stm->data->unlink(stm->data, src->output.master, 884cc842407SAlexander Shishkin src->output.channel); 885cc842407SAlexander Shishkin } 886cc842407SAlexander Shishkin 887b4ca34aaSAlexander Shishkin return ret; 8887bd1d409SAlexander Shishkin } 8897bd1d409SAlexander Shishkin 8907bd1d409SAlexander Shishkin /** 8917bd1d409SAlexander Shishkin * stm_source_link_drop() - detach stm_source from its stm device 8927bd1d409SAlexander Shishkin * @src: stm_source device 8937bd1d409SAlexander Shishkin * 8947bd1d409SAlexander Shishkin * Unlinking means disconnecting from source's STM device; after this 8957bd1d409SAlexander Shishkin * writes will be unsuccessful until it is linked to a new STM device. 8967bd1d409SAlexander Shishkin * 8977bd1d409SAlexander Shishkin * This will happen on "stm_source_link" sysfs attribute write to undo 8987bd1d409SAlexander Shishkin * the existing link (if any), or on linked STM device's de-registration. 8997bd1d409SAlexander Shishkin */ 9007bd1d409SAlexander Shishkin static void stm_source_link_drop(struct stm_source_device *src) 9017bd1d409SAlexander Shishkin { 9027bd1d409SAlexander Shishkin struct stm_device *stm; 903b4ca34aaSAlexander Shishkin int idx, ret; 9047bd1d409SAlexander Shishkin 905b4ca34aaSAlexander Shishkin retry: 9067bd1d409SAlexander Shishkin idx = srcu_read_lock(&stm_source_srcu); 907b4ca34aaSAlexander Shishkin /* 908b4ca34aaSAlexander Shishkin * The stm device will be valid for the duration of this 909b4ca34aaSAlexander Shishkin * read section, but the link may change before we grab 910b4ca34aaSAlexander Shishkin * the src::link_lock in __stm_source_link_drop(). 911b4ca34aaSAlexander Shishkin */ 9127bd1d409SAlexander Shishkin stm = srcu_dereference(src->link, &stm_source_srcu); 9137bd1d409SAlexander Shishkin 914b4ca34aaSAlexander Shishkin ret = 0; 9157bd1d409SAlexander Shishkin if (stm) { 916c74f7e82SAlexander Shishkin mutex_lock(&stm->link_mutex); 917b4ca34aaSAlexander Shishkin ret = __stm_source_link_drop(src, stm); 918c74f7e82SAlexander Shishkin mutex_unlock(&stm->link_mutex); 9197bd1d409SAlexander Shishkin } 9207bd1d409SAlexander Shishkin 9217bd1d409SAlexander Shishkin srcu_read_unlock(&stm_source_srcu, idx); 922b4ca34aaSAlexander Shishkin 923b4ca34aaSAlexander Shishkin /* if it did change, retry */ 924b4ca34aaSAlexander Shishkin if (ret == -EAGAIN) 925b4ca34aaSAlexander Shishkin goto retry; 9267bd1d409SAlexander Shishkin } 9277bd1d409SAlexander Shishkin 9287bd1d409SAlexander Shishkin static ssize_t stm_source_link_show(struct device *dev, 9297bd1d409SAlexander Shishkin struct device_attribute *attr, 9307bd1d409SAlexander Shishkin char *buf) 9317bd1d409SAlexander Shishkin { 9327bd1d409SAlexander Shishkin struct stm_source_device *src = to_stm_source_device(dev); 9337bd1d409SAlexander Shishkin struct stm_device *stm; 9347bd1d409SAlexander Shishkin int idx, ret; 9357bd1d409SAlexander Shishkin 9367bd1d409SAlexander Shishkin idx = srcu_read_lock(&stm_source_srcu); 9377bd1d409SAlexander Shishkin stm = srcu_dereference(src->link, &stm_source_srcu); 9387bd1d409SAlexander Shishkin ret = sprintf(buf, "%s\n", 9397bd1d409SAlexander Shishkin stm ? dev_name(&stm->dev) : "<none>"); 9407bd1d409SAlexander Shishkin srcu_read_unlock(&stm_source_srcu, idx); 9417bd1d409SAlexander Shishkin 9427bd1d409SAlexander Shishkin return ret; 9437bd1d409SAlexander Shishkin } 9447bd1d409SAlexander Shishkin 9457bd1d409SAlexander Shishkin static ssize_t stm_source_link_store(struct device *dev, 9467bd1d409SAlexander Shishkin struct device_attribute *attr, 9477bd1d409SAlexander Shishkin const char *buf, size_t count) 9487bd1d409SAlexander Shishkin { 9497bd1d409SAlexander Shishkin struct stm_source_device *src = to_stm_source_device(dev); 9507bd1d409SAlexander Shishkin struct stm_device *link; 9517bd1d409SAlexander Shishkin int err; 9527bd1d409SAlexander Shishkin 9537bd1d409SAlexander Shishkin stm_source_link_drop(src); 9547bd1d409SAlexander Shishkin 9557bd1d409SAlexander Shishkin link = stm_find_device(buf); 9567bd1d409SAlexander Shishkin if (!link) 9577bd1d409SAlexander Shishkin return -EINVAL; 9587bd1d409SAlexander Shishkin 9597bd1d409SAlexander Shishkin err = stm_source_link_add(src, link); 960f7c81c71SAlexander Shishkin if (err) { 961f7c81c71SAlexander Shishkin /* matches the stm_find_device() above */ 9627bd1d409SAlexander Shishkin stm_put_device(link); 963f7c81c71SAlexander Shishkin } 9647bd1d409SAlexander Shishkin 9657bd1d409SAlexander Shishkin return err ? : count; 9667bd1d409SAlexander Shishkin } 9677bd1d409SAlexander Shishkin 9687bd1d409SAlexander Shishkin static DEVICE_ATTR_RW(stm_source_link); 9697bd1d409SAlexander Shishkin 9707bd1d409SAlexander Shishkin static struct attribute *stm_source_attrs[] = { 9717bd1d409SAlexander Shishkin &dev_attr_stm_source_link.attr, 9727bd1d409SAlexander Shishkin NULL, 9737bd1d409SAlexander Shishkin }; 9747bd1d409SAlexander Shishkin 9757bd1d409SAlexander Shishkin ATTRIBUTE_GROUPS(stm_source); 9767bd1d409SAlexander Shishkin 9777bd1d409SAlexander Shishkin static struct class stm_source_class = { 9787bd1d409SAlexander Shishkin .name = "stm_source", 9797bd1d409SAlexander Shishkin .dev_groups = stm_source_groups, 9807bd1d409SAlexander Shishkin }; 9817bd1d409SAlexander Shishkin 9827bd1d409SAlexander Shishkin static void stm_source_device_release(struct device *dev) 9837bd1d409SAlexander Shishkin { 9847bd1d409SAlexander Shishkin struct stm_source_device *src = to_stm_source_device(dev); 9857bd1d409SAlexander Shishkin 9867bd1d409SAlexander Shishkin kfree(src); 9877bd1d409SAlexander Shishkin } 9887bd1d409SAlexander Shishkin 9897bd1d409SAlexander Shishkin /** 9907bd1d409SAlexander Shishkin * stm_source_register_device() - register an stm_source device 9917bd1d409SAlexander Shishkin * @parent: parent device 9927bd1d409SAlexander Shishkin * @data: device description structure 9937bd1d409SAlexander Shishkin * 9947bd1d409SAlexander Shishkin * This will create a device of stm_source class that can write 9957bd1d409SAlexander Shishkin * data to an stm device once linked. 9967bd1d409SAlexander Shishkin * 9977bd1d409SAlexander Shishkin * Return: 0 on success, -errno otherwise. 9987bd1d409SAlexander Shishkin */ 9997bd1d409SAlexander Shishkin int stm_source_register_device(struct device *parent, 10007bd1d409SAlexander Shishkin struct stm_source_data *data) 10017bd1d409SAlexander Shishkin { 10027bd1d409SAlexander Shishkin struct stm_source_device *src; 10037bd1d409SAlexander Shishkin int err; 10047bd1d409SAlexander Shishkin 10057bd1d409SAlexander Shishkin if (!stm_core_up) 10067bd1d409SAlexander Shishkin return -EPROBE_DEFER; 10077bd1d409SAlexander Shishkin 10087bd1d409SAlexander Shishkin src = kzalloc(sizeof(*src), GFP_KERNEL); 10097bd1d409SAlexander Shishkin if (!src) 10107bd1d409SAlexander Shishkin return -ENOMEM; 10117bd1d409SAlexander Shishkin 10127bd1d409SAlexander Shishkin device_initialize(&src->dev); 10137bd1d409SAlexander Shishkin src->dev.class = &stm_source_class; 10147bd1d409SAlexander Shishkin src->dev.parent = parent; 10157bd1d409SAlexander Shishkin src->dev.release = stm_source_device_release; 10167bd1d409SAlexander Shishkin 10177bd1d409SAlexander Shishkin err = kobject_set_name(&src->dev.kobj, "%s", data->name); 10187bd1d409SAlexander Shishkin if (err) 10197bd1d409SAlexander Shishkin goto err; 10207bd1d409SAlexander Shishkin 10217bd1d409SAlexander Shishkin err = device_add(&src->dev); 10227bd1d409SAlexander Shishkin if (err) 10237bd1d409SAlexander Shishkin goto err; 10247bd1d409SAlexander Shishkin 1025cde4ad83SAlexander Shishkin stm_output_init(&src->output); 10267bd1d409SAlexander Shishkin spin_lock_init(&src->link_lock); 10277bd1d409SAlexander Shishkin INIT_LIST_HEAD(&src->link_entry); 10287bd1d409SAlexander Shishkin src->data = data; 10297bd1d409SAlexander Shishkin data->src = src; 10307bd1d409SAlexander Shishkin 10317bd1d409SAlexander Shishkin return 0; 10327bd1d409SAlexander Shishkin 10337bd1d409SAlexander Shishkin err: 10347bd1d409SAlexander Shishkin put_device(&src->dev); 10357bd1d409SAlexander Shishkin kfree(src); 10367bd1d409SAlexander Shishkin 10377bd1d409SAlexander Shishkin return err; 10387bd1d409SAlexander Shishkin } 10397bd1d409SAlexander Shishkin EXPORT_SYMBOL_GPL(stm_source_register_device); 10407bd1d409SAlexander Shishkin 10417bd1d409SAlexander Shishkin /** 10427bd1d409SAlexander Shishkin * stm_source_unregister_device() - unregister an stm_source device 10437bd1d409SAlexander Shishkin * @data: device description that was used to register the device 10447bd1d409SAlexander Shishkin * 10457bd1d409SAlexander Shishkin * This will remove a previously created stm_source device from the system. 10467bd1d409SAlexander Shishkin */ 10477bd1d409SAlexander Shishkin void stm_source_unregister_device(struct stm_source_data *data) 10487bd1d409SAlexander Shishkin { 10497bd1d409SAlexander Shishkin struct stm_source_device *src = data->src; 10507bd1d409SAlexander Shishkin 10517bd1d409SAlexander Shishkin stm_source_link_drop(src); 10527bd1d409SAlexander Shishkin 10537bd1d409SAlexander Shishkin device_destroy(&stm_source_class, src->dev.devt); 10547bd1d409SAlexander Shishkin } 10557bd1d409SAlexander Shishkin EXPORT_SYMBOL_GPL(stm_source_unregister_device); 10567bd1d409SAlexander Shishkin 10577bd1d409SAlexander Shishkin int stm_source_write(struct stm_source_data *data, unsigned int chan, 10587bd1d409SAlexander Shishkin const char *buf, size_t count) 10597bd1d409SAlexander Shishkin { 10607bd1d409SAlexander Shishkin struct stm_source_device *src = data->src; 10617bd1d409SAlexander Shishkin struct stm_device *stm; 10627bd1d409SAlexander Shishkin int idx; 10637bd1d409SAlexander Shishkin 10647bd1d409SAlexander Shishkin if (!src->output.nr_chans) 10657bd1d409SAlexander Shishkin return -ENODEV; 10667bd1d409SAlexander Shishkin 10677bd1d409SAlexander Shishkin if (chan >= src->output.nr_chans) 10687bd1d409SAlexander Shishkin return -EINVAL; 10697bd1d409SAlexander Shishkin 10707bd1d409SAlexander Shishkin idx = srcu_read_lock(&stm_source_srcu); 10717bd1d409SAlexander Shishkin 10727bd1d409SAlexander Shishkin stm = srcu_dereference(src->link, &stm_source_srcu); 10737bd1d409SAlexander Shishkin if (stm) 1074f8560a9bSAlexander Shishkin count = stm_write(stm->data, src->output.master, 10757bd1d409SAlexander Shishkin src->output.channel + chan, 10767bd1d409SAlexander Shishkin buf, count); 10777bd1d409SAlexander Shishkin else 10787bd1d409SAlexander Shishkin count = -ENODEV; 10797bd1d409SAlexander Shishkin 10807bd1d409SAlexander Shishkin srcu_read_unlock(&stm_source_srcu, idx); 10817bd1d409SAlexander Shishkin 10827bd1d409SAlexander Shishkin return count; 10837bd1d409SAlexander Shishkin } 10847bd1d409SAlexander Shishkin EXPORT_SYMBOL_GPL(stm_source_write); 10857bd1d409SAlexander Shishkin 10867bd1d409SAlexander Shishkin static int __init stm_core_init(void) 10877bd1d409SAlexander Shishkin { 10887bd1d409SAlexander Shishkin int err; 10897bd1d409SAlexander Shishkin 10907bd1d409SAlexander Shishkin err = class_register(&stm_class); 10917bd1d409SAlexander Shishkin if (err) 10927bd1d409SAlexander Shishkin return err; 10937bd1d409SAlexander Shishkin 10947bd1d409SAlexander Shishkin err = class_register(&stm_source_class); 10957bd1d409SAlexander Shishkin if (err) 10967bd1d409SAlexander Shishkin goto err_stm; 10977bd1d409SAlexander Shishkin 10987bd1d409SAlexander Shishkin err = stp_configfs_init(); 10997bd1d409SAlexander Shishkin if (err) 11007bd1d409SAlexander Shishkin goto err_src; 11017bd1d409SAlexander Shishkin 11027bd1d409SAlexander Shishkin init_srcu_struct(&stm_source_srcu); 11037bd1d409SAlexander Shishkin 11047bd1d409SAlexander Shishkin stm_core_up++; 11057bd1d409SAlexander Shishkin 11067bd1d409SAlexander Shishkin return 0; 11077bd1d409SAlexander Shishkin 11087bd1d409SAlexander Shishkin err_src: 11097bd1d409SAlexander Shishkin class_unregister(&stm_source_class); 11107bd1d409SAlexander Shishkin err_stm: 11117bd1d409SAlexander Shishkin class_unregister(&stm_class); 11127bd1d409SAlexander Shishkin 11137bd1d409SAlexander Shishkin return err; 11147bd1d409SAlexander Shishkin } 11157bd1d409SAlexander Shishkin 11167bd1d409SAlexander Shishkin module_init(stm_core_init); 11177bd1d409SAlexander Shishkin 11187bd1d409SAlexander Shishkin static void __exit stm_core_exit(void) 11197bd1d409SAlexander Shishkin { 11207bd1d409SAlexander Shishkin cleanup_srcu_struct(&stm_source_srcu); 11217bd1d409SAlexander Shishkin class_unregister(&stm_source_class); 11227bd1d409SAlexander Shishkin class_unregister(&stm_class); 11237bd1d409SAlexander Shishkin stp_configfs_exit(); 11247bd1d409SAlexander Shishkin } 11257bd1d409SAlexander Shishkin 11267bd1d409SAlexander Shishkin module_exit(stm_core_exit); 11277bd1d409SAlexander Shishkin 11287bd1d409SAlexander Shishkin MODULE_LICENSE("GPL v2"); 11297bd1d409SAlexander Shishkin MODULE_DESCRIPTION("System Trace Module device class"); 11307bd1d409SAlexander Shishkin MODULE_AUTHOR("Alexander Shishkin <alexander.shishkin@linux.intel.com>"); 1131