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)) { 1167bd1d409SAlexander Shishkin put_device(dev); 1177bd1d409SAlexander Shishkin return NULL; 1187bd1d409SAlexander Shishkin } 1197bd1d409SAlexander Shishkin 1207bd1d409SAlexander Shishkin return stm; 1217bd1d409SAlexander Shishkin } 1227bd1d409SAlexander Shishkin 1237bd1d409SAlexander Shishkin /** 1247bd1d409SAlexander Shishkin * stm_put_device() - drop references on the stm device 1257bd1d409SAlexander Shishkin * @stm: stm device, previously acquired by stm_find_device() 1267bd1d409SAlexander Shishkin * 1277bd1d409SAlexander Shishkin * This drops the module reference and device reference taken by 1287bd1d409SAlexander Shishkin * stm_find_device(). 1297bd1d409SAlexander Shishkin */ 1307bd1d409SAlexander Shishkin void stm_put_device(struct stm_device *stm) 1317bd1d409SAlexander Shishkin { 1327bd1d409SAlexander Shishkin module_put(stm->owner); 1337bd1d409SAlexander Shishkin put_device(&stm->dev); 1347bd1d409SAlexander Shishkin } 1357bd1d409SAlexander Shishkin 1367bd1d409SAlexander Shishkin /* 1377bd1d409SAlexander Shishkin * Internally we only care about software-writable masters here, that is the 1387bd1d409SAlexander Shishkin * ones in the range [stm_data->sw_start..stm_data..sw_end], however we need 1397bd1d409SAlexander Shishkin * original master numbers to be visible externally, since they are the ones 1407bd1d409SAlexander Shishkin * that will appear in the STP stream. Thus, the internal bookkeeping uses 1417bd1d409SAlexander Shishkin * $master - stm_data->sw_start to reference master descriptors and such. 1427bd1d409SAlexander Shishkin */ 1437bd1d409SAlexander Shishkin 1447bd1d409SAlexander Shishkin #define __stm_master(_s, _m) \ 1457bd1d409SAlexander Shishkin ((_s)->masters[(_m) - (_s)->data->sw_start]) 1467bd1d409SAlexander Shishkin 1477bd1d409SAlexander Shishkin static inline struct stp_master * 1487bd1d409SAlexander Shishkin stm_master(struct stm_device *stm, unsigned int idx) 1497bd1d409SAlexander Shishkin { 1507bd1d409SAlexander Shishkin if (idx < stm->data->sw_start || idx > stm->data->sw_end) 1517bd1d409SAlexander Shishkin return NULL; 1527bd1d409SAlexander Shishkin 1537bd1d409SAlexander Shishkin return __stm_master(stm, idx); 1547bd1d409SAlexander Shishkin } 1557bd1d409SAlexander Shishkin 1567bd1d409SAlexander Shishkin static int stp_master_alloc(struct stm_device *stm, unsigned int idx) 1577bd1d409SAlexander Shishkin { 1587bd1d409SAlexander Shishkin struct stp_master *master; 1597bd1d409SAlexander Shishkin size_t size; 1607bd1d409SAlexander Shishkin 1617bd1d409SAlexander Shishkin size = ALIGN(stm->data->sw_nchannels, 8) / 8; 1627bd1d409SAlexander Shishkin size += sizeof(struct stp_master); 1637bd1d409SAlexander Shishkin master = kzalloc(size, GFP_ATOMIC); 1647bd1d409SAlexander Shishkin if (!master) 1657bd1d409SAlexander Shishkin return -ENOMEM; 1667bd1d409SAlexander Shishkin 1677bd1d409SAlexander Shishkin master->nr_free = stm->data->sw_nchannels; 1687bd1d409SAlexander Shishkin __stm_master(stm, idx) = master; 1697bd1d409SAlexander Shishkin 1707bd1d409SAlexander Shishkin return 0; 1717bd1d409SAlexander Shishkin } 1727bd1d409SAlexander Shishkin 1737bd1d409SAlexander Shishkin static void stp_master_free(struct stm_device *stm, unsigned int idx) 1747bd1d409SAlexander Shishkin { 1757bd1d409SAlexander Shishkin struct stp_master *master = stm_master(stm, idx); 1767bd1d409SAlexander Shishkin 1777bd1d409SAlexander Shishkin if (!master) 1787bd1d409SAlexander Shishkin return; 1797bd1d409SAlexander Shishkin 1807bd1d409SAlexander Shishkin __stm_master(stm, idx) = NULL; 1817bd1d409SAlexander Shishkin kfree(master); 1827bd1d409SAlexander Shishkin } 1837bd1d409SAlexander Shishkin 1847bd1d409SAlexander Shishkin static void stm_output_claim(struct stm_device *stm, struct stm_output *output) 1857bd1d409SAlexander Shishkin { 1867bd1d409SAlexander Shishkin struct stp_master *master = stm_master(stm, output->master); 1877bd1d409SAlexander Shishkin 1887bd1d409SAlexander Shishkin if (WARN_ON_ONCE(master->nr_free < output->nr_chans)) 1897bd1d409SAlexander Shishkin return; 1907bd1d409SAlexander Shishkin 1917bd1d409SAlexander Shishkin bitmap_allocate_region(&master->chan_map[0], output->channel, 1927bd1d409SAlexander Shishkin ilog2(output->nr_chans)); 1937bd1d409SAlexander Shishkin 1947bd1d409SAlexander Shishkin master->nr_free -= output->nr_chans; 1957bd1d409SAlexander Shishkin } 1967bd1d409SAlexander Shishkin 1977bd1d409SAlexander Shishkin static void 1987bd1d409SAlexander Shishkin stm_output_disclaim(struct stm_device *stm, struct stm_output *output) 1997bd1d409SAlexander Shishkin { 2007bd1d409SAlexander Shishkin struct stp_master *master = stm_master(stm, output->master); 2017bd1d409SAlexander Shishkin 2027bd1d409SAlexander Shishkin bitmap_release_region(&master->chan_map[0], output->channel, 2037bd1d409SAlexander Shishkin ilog2(output->nr_chans)); 2047bd1d409SAlexander Shishkin 2057bd1d409SAlexander Shishkin output->nr_chans = 0; 2067bd1d409SAlexander Shishkin master->nr_free += output->nr_chans; 2077bd1d409SAlexander Shishkin } 2087bd1d409SAlexander Shishkin 2097bd1d409SAlexander Shishkin /* 2107bd1d409SAlexander Shishkin * This is like bitmap_find_free_region(), except it can ignore @start bits 2117bd1d409SAlexander Shishkin * at the beginning. 2127bd1d409SAlexander Shishkin */ 2137bd1d409SAlexander Shishkin static int find_free_channels(unsigned long *bitmap, unsigned int start, 2147bd1d409SAlexander Shishkin unsigned int end, unsigned int width) 2157bd1d409SAlexander Shishkin { 2167bd1d409SAlexander Shishkin unsigned int pos; 2177bd1d409SAlexander Shishkin int i; 2187bd1d409SAlexander Shishkin 2197bd1d409SAlexander Shishkin for (pos = start; pos < end + 1; pos = ALIGN(pos, width)) { 2207bd1d409SAlexander Shishkin pos = find_next_zero_bit(bitmap, end + 1, pos); 2217bd1d409SAlexander Shishkin if (pos + width > end + 1) 2227bd1d409SAlexander Shishkin break; 2237bd1d409SAlexander Shishkin 2247bd1d409SAlexander Shishkin if (pos & (width - 1)) 2257bd1d409SAlexander Shishkin continue; 2267bd1d409SAlexander Shishkin 2277bd1d409SAlexander Shishkin for (i = 1; i < width && !test_bit(pos + i, bitmap); i++) 2287bd1d409SAlexander Shishkin ; 2297bd1d409SAlexander Shishkin if (i == width) 2307bd1d409SAlexander Shishkin return pos; 2317bd1d409SAlexander Shishkin } 2327bd1d409SAlexander Shishkin 2337bd1d409SAlexander Shishkin return -1; 2347bd1d409SAlexander Shishkin } 2357bd1d409SAlexander Shishkin 2367bd1d409SAlexander Shishkin static unsigned int 2377bd1d409SAlexander Shishkin stm_find_master_chan(struct stm_device *stm, unsigned int width, 2387bd1d409SAlexander Shishkin unsigned int *mstart, unsigned int mend, 2397bd1d409SAlexander Shishkin unsigned int *cstart, unsigned int cend) 2407bd1d409SAlexander Shishkin { 2417bd1d409SAlexander Shishkin struct stp_master *master; 2427bd1d409SAlexander Shishkin unsigned int midx; 2437bd1d409SAlexander Shishkin int pos, err; 2447bd1d409SAlexander Shishkin 2457bd1d409SAlexander Shishkin for (midx = *mstart; midx <= mend; midx++) { 2467bd1d409SAlexander Shishkin if (!stm_master(stm, midx)) { 2477bd1d409SAlexander Shishkin err = stp_master_alloc(stm, midx); 2487bd1d409SAlexander Shishkin if (err) 2497bd1d409SAlexander Shishkin return err; 2507bd1d409SAlexander Shishkin } 2517bd1d409SAlexander Shishkin 2527bd1d409SAlexander Shishkin master = stm_master(stm, midx); 2537bd1d409SAlexander Shishkin 2547bd1d409SAlexander Shishkin if (!master->nr_free) 2557bd1d409SAlexander Shishkin continue; 2567bd1d409SAlexander Shishkin 2577bd1d409SAlexander Shishkin pos = find_free_channels(master->chan_map, *cstart, cend, 2587bd1d409SAlexander Shishkin width); 2597bd1d409SAlexander Shishkin if (pos < 0) 2607bd1d409SAlexander Shishkin continue; 2617bd1d409SAlexander Shishkin 2627bd1d409SAlexander Shishkin *mstart = midx; 2637bd1d409SAlexander Shishkin *cstart = pos; 2647bd1d409SAlexander Shishkin return 0; 2657bd1d409SAlexander Shishkin } 2667bd1d409SAlexander Shishkin 2677bd1d409SAlexander Shishkin return -ENOSPC; 2687bd1d409SAlexander Shishkin } 2697bd1d409SAlexander Shishkin 2707bd1d409SAlexander Shishkin static int stm_output_assign(struct stm_device *stm, unsigned int width, 2717bd1d409SAlexander Shishkin struct stp_policy_node *policy_node, 2727bd1d409SAlexander Shishkin struct stm_output *output) 2737bd1d409SAlexander Shishkin { 2747bd1d409SAlexander Shishkin unsigned int midx, cidx, mend, cend; 2757bd1d409SAlexander Shishkin int ret = -EINVAL; 2767bd1d409SAlexander Shishkin 2777bd1d409SAlexander Shishkin if (width > stm->data->sw_nchannels) 2787bd1d409SAlexander Shishkin return -EINVAL; 2797bd1d409SAlexander Shishkin 2807bd1d409SAlexander Shishkin if (policy_node) { 2817bd1d409SAlexander Shishkin stp_policy_node_get_ranges(policy_node, 2827bd1d409SAlexander Shishkin &midx, &mend, &cidx, &cend); 2837bd1d409SAlexander Shishkin } else { 2847bd1d409SAlexander Shishkin midx = stm->data->sw_start; 2857bd1d409SAlexander Shishkin cidx = 0; 2867bd1d409SAlexander Shishkin mend = stm->data->sw_end; 2877bd1d409SAlexander Shishkin cend = stm->data->sw_nchannels - 1; 2887bd1d409SAlexander Shishkin } 2897bd1d409SAlexander Shishkin 2907bd1d409SAlexander Shishkin spin_lock(&stm->mc_lock); 2917bd1d409SAlexander Shishkin /* output is already assigned -- shouldn't happen */ 2927bd1d409SAlexander Shishkin if (WARN_ON_ONCE(output->nr_chans)) 2937bd1d409SAlexander Shishkin goto unlock; 2947bd1d409SAlexander Shishkin 2957bd1d409SAlexander Shishkin ret = stm_find_master_chan(stm, width, &midx, mend, &cidx, cend); 2967bd1d409SAlexander Shishkin if (ret) 2977bd1d409SAlexander Shishkin goto unlock; 2987bd1d409SAlexander Shishkin 2997bd1d409SAlexander Shishkin output->master = midx; 3007bd1d409SAlexander Shishkin output->channel = cidx; 3017bd1d409SAlexander Shishkin output->nr_chans = width; 3027bd1d409SAlexander Shishkin stm_output_claim(stm, output); 3037bd1d409SAlexander Shishkin dev_dbg(&stm->dev, "assigned %u:%u (+%u)\n", midx, cidx, width); 3047bd1d409SAlexander Shishkin 3057bd1d409SAlexander Shishkin ret = 0; 3067bd1d409SAlexander Shishkin unlock: 3077bd1d409SAlexander Shishkin spin_unlock(&stm->mc_lock); 3087bd1d409SAlexander Shishkin 3097bd1d409SAlexander Shishkin return ret; 3107bd1d409SAlexander Shishkin } 3117bd1d409SAlexander Shishkin 3127bd1d409SAlexander Shishkin static void stm_output_free(struct stm_device *stm, struct stm_output *output) 3137bd1d409SAlexander Shishkin { 3147bd1d409SAlexander Shishkin spin_lock(&stm->mc_lock); 3157bd1d409SAlexander Shishkin if (output->nr_chans) 3167bd1d409SAlexander Shishkin stm_output_disclaim(stm, output); 3177bd1d409SAlexander Shishkin spin_unlock(&stm->mc_lock); 3187bd1d409SAlexander Shishkin } 3197bd1d409SAlexander Shishkin 3207bd1d409SAlexander Shishkin static int major_match(struct device *dev, const void *data) 3217bd1d409SAlexander Shishkin { 3227bd1d409SAlexander Shishkin unsigned int major = *(unsigned int *)data; 3237bd1d409SAlexander Shishkin 3247bd1d409SAlexander Shishkin return MAJOR(dev->devt) == major; 3257bd1d409SAlexander Shishkin } 3267bd1d409SAlexander Shishkin 3277bd1d409SAlexander Shishkin static int stm_char_open(struct inode *inode, struct file *file) 3287bd1d409SAlexander Shishkin { 3297bd1d409SAlexander Shishkin struct stm_file *stmf; 3307bd1d409SAlexander Shishkin struct device *dev; 3317bd1d409SAlexander Shishkin unsigned int major = imajor(inode); 3327bd1d409SAlexander Shishkin int err = -ENODEV; 3337bd1d409SAlexander Shishkin 3347bd1d409SAlexander Shishkin dev = class_find_device(&stm_class, NULL, &major, major_match); 3357bd1d409SAlexander Shishkin if (!dev) 3367bd1d409SAlexander Shishkin return -ENODEV; 3377bd1d409SAlexander Shishkin 3387bd1d409SAlexander Shishkin stmf = kzalloc(sizeof(*stmf), GFP_KERNEL); 3397bd1d409SAlexander Shishkin if (!stmf) 3407bd1d409SAlexander Shishkin return -ENOMEM; 3417bd1d409SAlexander Shishkin 3427bd1d409SAlexander Shishkin stmf->stm = to_stm_device(dev); 3437bd1d409SAlexander Shishkin 3447bd1d409SAlexander Shishkin if (!try_module_get(stmf->stm->owner)) 3457bd1d409SAlexander Shishkin goto err_free; 3467bd1d409SAlexander Shishkin 3477bd1d409SAlexander Shishkin file->private_data = stmf; 3487bd1d409SAlexander Shishkin 3497bd1d409SAlexander Shishkin return nonseekable_open(inode, file); 3507bd1d409SAlexander Shishkin 3517bd1d409SAlexander Shishkin err_free: 3527bd1d409SAlexander Shishkin kfree(stmf); 3537bd1d409SAlexander Shishkin 3547bd1d409SAlexander Shishkin return err; 3557bd1d409SAlexander Shishkin } 3567bd1d409SAlexander Shishkin 3577bd1d409SAlexander Shishkin static int stm_char_release(struct inode *inode, struct file *file) 3587bd1d409SAlexander Shishkin { 3597bd1d409SAlexander Shishkin struct stm_file *stmf = file->private_data; 3607bd1d409SAlexander Shishkin 3617bd1d409SAlexander Shishkin stm_output_free(stmf->stm, &stmf->output); 3627bd1d409SAlexander Shishkin stm_put_device(stmf->stm); 3637bd1d409SAlexander Shishkin kfree(stmf); 3647bd1d409SAlexander Shishkin 3657bd1d409SAlexander Shishkin return 0; 3667bd1d409SAlexander Shishkin } 3677bd1d409SAlexander Shishkin 3687bd1d409SAlexander Shishkin static int stm_file_assign(struct stm_file *stmf, char *id, unsigned int width) 3697bd1d409SAlexander Shishkin { 3707bd1d409SAlexander Shishkin struct stm_device *stm = stmf->stm; 3717bd1d409SAlexander Shishkin int ret; 3727bd1d409SAlexander Shishkin 3737bd1d409SAlexander Shishkin stmf->policy_node = stp_policy_node_lookup(stm, id); 3747bd1d409SAlexander Shishkin 3757bd1d409SAlexander Shishkin ret = stm_output_assign(stm, width, stmf->policy_node, &stmf->output); 3767bd1d409SAlexander Shishkin 3777bd1d409SAlexander Shishkin if (stmf->policy_node) 3787bd1d409SAlexander Shishkin stp_policy_node_put(stmf->policy_node); 3797bd1d409SAlexander Shishkin 3807bd1d409SAlexander Shishkin return ret; 3817bd1d409SAlexander Shishkin } 3827bd1d409SAlexander Shishkin 3837bd1d409SAlexander Shishkin static void stm_write(struct stm_data *data, unsigned int master, 3847bd1d409SAlexander Shishkin unsigned int channel, const char *buf, size_t count) 3857bd1d409SAlexander Shishkin { 3867bd1d409SAlexander Shishkin unsigned int flags = STP_PACKET_TIMESTAMPED; 3877bd1d409SAlexander Shishkin const unsigned char *p = buf, nil = 0; 3887bd1d409SAlexander Shishkin size_t pos; 3897bd1d409SAlexander Shishkin ssize_t sz; 3907bd1d409SAlexander Shishkin 3917bd1d409SAlexander Shishkin for (pos = 0, p = buf; count > pos; pos += sz, p += sz) { 3927bd1d409SAlexander Shishkin sz = min_t(unsigned int, count - pos, 8); 3937bd1d409SAlexander Shishkin sz = data->packet(data, master, channel, STP_PACKET_DATA, flags, 3947bd1d409SAlexander Shishkin sz, p); 3957bd1d409SAlexander Shishkin flags = 0; 3967bd1d409SAlexander Shishkin } 3977bd1d409SAlexander Shishkin 3987bd1d409SAlexander Shishkin data->packet(data, master, channel, STP_PACKET_FLAG, 0, 0, &nil); 3997bd1d409SAlexander Shishkin } 4007bd1d409SAlexander Shishkin 4017bd1d409SAlexander Shishkin static ssize_t stm_char_write(struct file *file, const char __user *buf, 4027bd1d409SAlexander Shishkin size_t count, loff_t *ppos) 4037bd1d409SAlexander Shishkin { 4047bd1d409SAlexander Shishkin struct stm_file *stmf = file->private_data; 4057bd1d409SAlexander Shishkin struct stm_device *stm = stmf->stm; 4067bd1d409SAlexander Shishkin char *kbuf; 4077bd1d409SAlexander Shishkin int err; 4087bd1d409SAlexander Shishkin 4097bd1d409SAlexander Shishkin /* 4107bd1d409SAlexander Shishkin * if no m/c have been assigned to this writer up to this 4117bd1d409SAlexander Shishkin * point, use "default" policy entry 4127bd1d409SAlexander Shishkin */ 4137bd1d409SAlexander Shishkin if (!stmf->output.nr_chans) { 4147bd1d409SAlexander Shishkin err = stm_file_assign(stmf, "default", 1); 4157bd1d409SAlexander Shishkin /* 4167bd1d409SAlexander Shishkin * EBUSY means that somebody else just assigned this 4177bd1d409SAlexander Shishkin * output, which is just fine for write() 4187bd1d409SAlexander Shishkin */ 4197bd1d409SAlexander Shishkin if (err && err != -EBUSY) 4207bd1d409SAlexander Shishkin return err; 4217bd1d409SAlexander Shishkin } 4227bd1d409SAlexander Shishkin 4237bd1d409SAlexander Shishkin kbuf = kmalloc(count + 1, GFP_KERNEL); 4247bd1d409SAlexander Shishkin if (!kbuf) 4257bd1d409SAlexander Shishkin return -ENOMEM; 4267bd1d409SAlexander Shishkin 4277bd1d409SAlexander Shishkin err = copy_from_user(kbuf, buf, count); 4287bd1d409SAlexander Shishkin if (err) { 4297bd1d409SAlexander Shishkin kfree(kbuf); 4307bd1d409SAlexander Shishkin return -EFAULT; 4317bd1d409SAlexander Shishkin } 4327bd1d409SAlexander Shishkin 4337bd1d409SAlexander Shishkin stm_write(stm->data, stmf->output.master, stmf->output.channel, kbuf, 4347bd1d409SAlexander Shishkin count); 4357bd1d409SAlexander Shishkin 4367bd1d409SAlexander Shishkin kfree(kbuf); 4377bd1d409SAlexander Shishkin 4387bd1d409SAlexander Shishkin return count; 4397bd1d409SAlexander Shishkin } 4407bd1d409SAlexander Shishkin 4417bd1d409SAlexander Shishkin static int stm_char_mmap(struct file *file, struct vm_area_struct *vma) 4427bd1d409SAlexander Shishkin { 4437bd1d409SAlexander Shishkin struct stm_file *stmf = file->private_data; 4447bd1d409SAlexander Shishkin struct stm_device *stm = stmf->stm; 4457bd1d409SAlexander Shishkin unsigned long size, phys; 4467bd1d409SAlexander Shishkin 4477bd1d409SAlexander Shishkin if (!stm->data->mmio_addr) 4487bd1d409SAlexander Shishkin return -EOPNOTSUPP; 4497bd1d409SAlexander Shishkin 4507bd1d409SAlexander Shishkin if (vma->vm_pgoff) 4517bd1d409SAlexander Shishkin return -EINVAL; 4527bd1d409SAlexander Shishkin 4537bd1d409SAlexander Shishkin size = vma->vm_end - vma->vm_start; 4547bd1d409SAlexander Shishkin 4557bd1d409SAlexander Shishkin if (stmf->output.nr_chans * stm->data->sw_mmiosz != size) 4567bd1d409SAlexander Shishkin return -EINVAL; 4577bd1d409SAlexander Shishkin 4587bd1d409SAlexander Shishkin phys = stm->data->mmio_addr(stm->data, stmf->output.master, 4597bd1d409SAlexander Shishkin stmf->output.channel, 4607bd1d409SAlexander Shishkin stmf->output.nr_chans); 4617bd1d409SAlexander Shishkin 4627bd1d409SAlexander Shishkin if (!phys) 4637bd1d409SAlexander Shishkin return -EINVAL; 4647bd1d409SAlexander Shishkin 4657bd1d409SAlexander Shishkin vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot); 4667bd1d409SAlexander Shishkin vma->vm_flags |= VM_IO | VM_DONTEXPAND | VM_DONTDUMP; 4677bd1d409SAlexander Shishkin vm_iomap_memory(vma, phys, size); 4687bd1d409SAlexander Shishkin 4697bd1d409SAlexander Shishkin return 0; 4707bd1d409SAlexander Shishkin } 4717bd1d409SAlexander Shishkin 4727bd1d409SAlexander Shishkin static int stm_char_policy_set_ioctl(struct stm_file *stmf, void __user *arg) 4737bd1d409SAlexander Shishkin { 4747bd1d409SAlexander Shishkin struct stm_device *stm = stmf->stm; 4757bd1d409SAlexander Shishkin struct stp_policy_id *id; 4767bd1d409SAlexander Shishkin int ret = -EINVAL; 4777bd1d409SAlexander Shishkin u32 size; 4787bd1d409SAlexander Shishkin 4797bd1d409SAlexander Shishkin if (stmf->output.nr_chans) 4807bd1d409SAlexander Shishkin return -EBUSY; 4817bd1d409SAlexander Shishkin 4827bd1d409SAlexander Shishkin if (copy_from_user(&size, arg, sizeof(size))) 4837bd1d409SAlexander Shishkin return -EFAULT; 4847bd1d409SAlexander Shishkin 4857bd1d409SAlexander Shishkin if (size >= PATH_MAX + sizeof(*id)) 4867bd1d409SAlexander Shishkin return -EINVAL; 4877bd1d409SAlexander Shishkin 4887bd1d409SAlexander Shishkin /* 4897bd1d409SAlexander Shishkin * size + 1 to make sure the .id string at the bottom is terminated, 4907bd1d409SAlexander Shishkin * which is also why memdup_user() is not useful here 4917bd1d409SAlexander Shishkin */ 4927bd1d409SAlexander Shishkin id = kzalloc(size + 1, GFP_KERNEL); 4937bd1d409SAlexander Shishkin if (!id) 4947bd1d409SAlexander Shishkin return -ENOMEM; 4957bd1d409SAlexander Shishkin 4967bd1d409SAlexander Shishkin if (copy_from_user(id, arg, size)) { 4977bd1d409SAlexander Shishkin ret = -EFAULT; 4987bd1d409SAlexander Shishkin goto err_free; 4997bd1d409SAlexander Shishkin } 5007bd1d409SAlexander Shishkin 5017bd1d409SAlexander Shishkin if (id->__reserved_0 || id->__reserved_1) 5027bd1d409SAlexander Shishkin goto err_free; 5037bd1d409SAlexander Shishkin 5047bd1d409SAlexander Shishkin if (id->width < 1 || 5057bd1d409SAlexander Shishkin id->width > PAGE_SIZE / stm->data->sw_mmiosz) 5067bd1d409SAlexander Shishkin goto err_free; 5077bd1d409SAlexander Shishkin 5087bd1d409SAlexander Shishkin ret = stm_file_assign(stmf, id->id, id->width); 5097bd1d409SAlexander Shishkin if (ret) 5107bd1d409SAlexander Shishkin goto err_free; 5117bd1d409SAlexander Shishkin 5127bd1d409SAlexander Shishkin ret = 0; 5137bd1d409SAlexander Shishkin 5147bd1d409SAlexander Shishkin if (stm->data->link) 5157bd1d409SAlexander Shishkin ret = stm->data->link(stm->data, stmf->output.master, 5167bd1d409SAlexander Shishkin stmf->output.channel); 5177bd1d409SAlexander Shishkin 5187bd1d409SAlexander Shishkin if (ret) { 5197bd1d409SAlexander Shishkin stm_output_free(stmf->stm, &stmf->output); 5207bd1d409SAlexander Shishkin stm_put_device(stmf->stm); 5217bd1d409SAlexander Shishkin } 5227bd1d409SAlexander Shishkin 5237bd1d409SAlexander Shishkin err_free: 5247bd1d409SAlexander Shishkin kfree(id); 5257bd1d409SAlexander Shishkin 5267bd1d409SAlexander Shishkin return ret; 5277bd1d409SAlexander Shishkin } 5287bd1d409SAlexander Shishkin 5297bd1d409SAlexander Shishkin static int stm_char_policy_get_ioctl(struct stm_file *stmf, void __user *arg) 5307bd1d409SAlexander Shishkin { 5317bd1d409SAlexander Shishkin struct stp_policy_id id = { 5327bd1d409SAlexander Shishkin .size = sizeof(id), 5337bd1d409SAlexander Shishkin .master = stmf->output.master, 5347bd1d409SAlexander Shishkin .channel = stmf->output.channel, 5357bd1d409SAlexander Shishkin .width = stmf->output.nr_chans, 5367bd1d409SAlexander Shishkin .__reserved_0 = 0, 5377bd1d409SAlexander Shishkin .__reserved_1 = 0, 5387bd1d409SAlexander Shishkin }; 5397bd1d409SAlexander Shishkin 5407bd1d409SAlexander Shishkin return copy_to_user(arg, &id, id.size) ? -EFAULT : 0; 5417bd1d409SAlexander Shishkin } 5427bd1d409SAlexander Shishkin 5437bd1d409SAlexander Shishkin static long 5447bd1d409SAlexander Shishkin stm_char_ioctl(struct file *file, unsigned int cmd, unsigned long arg) 5457bd1d409SAlexander Shishkin { 5467bd1d409SAlexander Shishkin struct stm_file *stmf = file->private_data; 5477bd1d409SAlexander Shishkin struct stm_data *stm_data = stmf->stm->data; 5487bd1d409SAlexander Shishkin int err = -ENOTTY; 5497bd1d409SAlexander Shishkin u64 options; 5507bd1d409SAlexander Shishkin 5517bd1d409SAlexander Shishkin switch (cmd) { 5527bd1d409SAlexander Shishkin case STP_POLICY_ID_SET: 5537bd1d409SAlexander Shishkin err = stm_char_policy_set_ioctl(stmf, (void __user *)arg); 5547bd1d409SAlexander Shishkin if (err) 5557bd1d409SAlexander Shishkin return err; 5567bd1d409SAlexander Shishkin 5577bd1d409SAlexander Shishkin return stm_char_policy_get_ioctl(stmf, (void __user *)arg); 5587bd1d409SAlexander Shishkin 5597bd1d409SAlexander Shishkin case STP_POLICY_ID_GET: 5607bd1d409SAlexander Shishkin return stm_char_policy_get_ioctl(stmf, (void __user *)arg); 5617bd1d409SAlexander Shishkin 5627bd1d409SAlexander Shishkin case STP_SET_OPTIONS: 5637bd1d409SAlexander Shishkin if (copy_from_user(&options, (u64 __user *)arg, sizeof(u64))) 5647bd1d409SAlexander Shishkin return -EFAULT; 5657bd1d409SAlexander Shishkin 5667bd1d409SAlexander Shishkin if (stm_data->set_options) 5677bd1d409SAlexander Shishkin err = stm_data->set_options(stm_data, 5687bd1d409SAlexander Shishkin stmf->output.master, 5697bd1d409SAlexander Shishkin stmf->output.channel, 5707bd1d409SAlexander Shishkin stmf->output.nr_chans, 5717bd1d409SAlexander Shishkin options); 5727bd1d409SAlexander Shishkin 5737bd1d409SAlexander Shishkin break; 5747bd1d409SAlexander Shishkin default: 5757bd1d409SAlexander Shishkin break; 5767bd1d409SAlexander Shishkin } 5777bd1d409SAlexander Shishkin 5787bd1d409SAlexander Shishkin return err; 5797bd1d409SAlexander Shishkin } 5807bd1d409SAlexander Shishkin 5817bd1d409SAlexander Shishkin #ifdef CONFIG_COMPAT 5827bd1d409SAlexander Shishkin static long 5837bd1d409SAlexander Shishkin stm_char_compat_ioctl(struct file *file, unsigned int cmd, unsigned long arg) 5847bd1d409SAlexander Shishkin { 5857bd1d409SAlexander Shishkin return stm_char_ioctl(file, cmd, (unsigned long)compat_ptr(arg)); 5867bd1d409SAlexander Shishkin } 5877bd1d409SAlexander Shishkin #else 5887bd1d409SAlexander Shishkin #define stm_char_compat_ioctl NULL 5897bd1d409SAlexander Shishkin #endif 5907bd1d409SAlexander Shishkin 5917bd1d409SAlexander Shishkin static const struct file_operations stm_fops = { 5927bd1d409SAlexander Shishkin .open = stm_char_open, 5937bd1d409SAlexander Shishkin .release = stm_char_release, 5947bd1d409SAlexander Shishkin .write = stm_char_write, 5957bd1d409SAlexander Shishkin .mmap = stm_char_mmap, 5967bd1d409SAlexander Shishkin .unlocked_ioctl = stm_char_ioctl, 5977bd1d409SAlexander Shishkin .compat_ioctl = stm_char_compat_ioctl, 5987bd1d409SAlexander Shishkin .llseek = no_llseek, 5997bd1d409SAlexander Shishkin }; 6007bd1d409SAlexander Shishkin 6017bd1d409SAlexander Shishkin static void stm_device_release(struct device *dev) 6027bd1d409SAlexander Shishkin { 6037bd1d409SAlexander Shishkin struct stm_device *stm = to_stm_device(dev); 6047bd1d409SAlexander Shishkin 6057bd1d409SAlexander Shishkin kfree(stm); 6067bd1d409SAlexander Shishkin } 6077bd1d409SAlexander Shishkin 6087bd1d409SAlexander Shishkin int stm_register_device(struct device *parent, struct stm_data *stm_data, 6097bd1d409SAlexander Shishkin struct module *owner) 6107bd1d409SAlexander Shishkin { 6117bd1d409SAlexander Shishkin struct stm_device *stm; 6127bd1d409SAlexander Shishkin unsigned int nmasters; 6137bd1d409SAlexander Shishkin int err = -ENOMEM; 6147bd1d409SAlexander Shishkin 6157bd1d409SAlexander Shishkin if (!stm_core_up) 6167bd1d409SAlexander Shishkin return -EPROBE_DEFER; 6177bd1d409SAlexander Shishkin 6187bd1d409SAlexander Shishkin if (!stm_data->packet || !stm_data->sw_nchannels) 6197bd1d409SAlexander Shishkin return -EINVAL; 6207bd1d409SAlexander Shishkin 6217b3bb0e7SChunyan Zhang nmasters = stm_data->sw_end - stm_data->sw_start + 1; 6227bd1d409SAlexander Shishkin stm = kzalloc(sizeof(*stm) + nmasters * sizeof(void *), GFP_KERNEL); 6237bd1d409SAlexander Shishkin if (!stm) 6247bd1d409SAlexander Shishkin return -ENOMEM; 6257bd1d409SAlexander Shishkin 6267bd1d409SAlexander Shishkin stm->major = register_chrdev(0, stm_data->name, &stm_fops); 6277bd1d409SAlexander Shishkin if (stm->major < 0) 6287bd1d409SAlexander Shishkin goto err_free; 6297bd1d409SAlexander Shishkin 6307bd1d409SAlexander Shishkin device_initialize(&stm->dev); 6317bd1d409SAlexander Shishkin stm->dev.devt = MKDEV(stm->major, 0); 6327bd1d409SAlexander Shishkin stm->dev.class = &stm_class; 6337bd1d409SAlexander Shishkin stm->dev.parent = parent; 6347bd1d409SAlexander Shishkin stm->dev.release = stm_device_release; 6357bd1d409SAlexander Shishkin 6367bd1d409SAlexander Shishkin err = kobject_set_name(&stm->dev.kobj, "%s", stm_data->name); 6377bd1d409SAlexander Shishkin if (err) 6387bd1d409SAlexander Shishkin goto err_device; 6397bd1d409SAlexander Shishkin 6407bd1d409SAlexander Shishkin err = device_add(&stm->dev); 6417bd1d409SAlexander Shishkin if (err) 6427bd1d409SAlexander Shishkin goto err_device; 6437bd1d409SAlexander Shishkin 644c74f7e82SAlexander Shishkin mutex_init(&stm->link_mutex); 6457bd1d409SAlexander Shishkin spin_lock_init(&stm->link_lock); 6467bd1d409SAlexander Shishkin INIT_LIST_HEAD(&stm->link_list); 6477bd1d409SAlexander Shishkin 6487bd1d409SAlexander Shishkin spin_lock_init(&stm->mc_lock); 6497bd1d409SAlexander Shishkin mutex_init(&stm->policy_mutex); 6507bd1d409SAlexander Shishkin stm->sw_nmasters = nmasters; 6517bd1d409SAlexander Shishkin stm->owner = owner; 6527bd1d409SAlexander Shishkin stm->data = stm_data; 6537bd1d409SAlexander Shishkin stm_data->stm = stm; 6547bd1d409SAlexander Shishkin 6557bd1d409SAlexander Shishkin return 0; 6567bd1d409SAlexander Shishkin 6577bd1d409SAlexander Shishkin err_device: 6587bd1d409SAlexander Shishkin put_device(&stm->dev); 6597bd1d409SAlexander Shishkin err_free: 6607bd1d409SAlexander Shishkin kfree(stm); 6617bd1d409SAlexander Shishkin 6627bd1d409SAlexander Shishkin return err; 6637bd1d409SAlexander Shishkin } 6647bd1d409SAlexander Shishkin EXPORT_SYMBOL_GPL(stm_register_device); 6657bd1d409SAlexander Shishkin 6667bd1d409SAlexander Shishkin static void __stm_source_link_drop(struct stm_source_device *src, 6677bd1d409SAlexander Shishkin struct stm_device *stm); 6687bd1d409SAlexander Shishkin 6697bd1d409SAlexander Shishkin void stm_unregister_device(struct stm_data *stm_data) 6707bd1d409SAlexander Shishkin { 6717bd1d409SAlexander Shishkin struct stm_device *stm = stm_data->stm; 6727bd1d409SAlexander Shishkin struct stm_source_device *src, *iter; 6737bd1d409SAlexander Shishkin int i; 6747bd1d409SAlexander Shishkin 675c74f7e82SAlexander Shishkin mutex_lock(&stm->link_mutex); 6767bd1d409SAlexander Shishkin list_for_each_entry_safe(src, iter, &stm->link_list, link_entry) { 6777bd1d409SAlexander Shishkin __stm_source_link_drop(src, stm); 6787bd1d409SAlexander Shishkin } 679c74f7e82SAlexander Shishkin mutex_unlock(&stm->link_mutex); 6807bd1d409SAlexander Shishkin 6817bd1d409SAlexander Shishkin synchronize_srcu(&stm_source_srcu); 6827bd1d409SAlexander Shishkin 6837bd1d409SAlexander Shishkin unregister_chrdev(stm->major, stm_data->name); 6847bd1d409SAlexander Shishkin 6857bd1d409SAlexander Shishkin mutex_lock(&stm->policy_mutex); 6867bd1d409SAlexander Shishkin if (stm->policy) 6877bd1d409SAlexander Shishkin stp_policy_unbind(stm->policy); 6887bd1d409SAlexander Shishkin mutex_unlock(&stm->policy_mutex); 6897bd1d409SAlexander Shishkin 6907bd1d409SAlexander Shishkin for (i = 0; i < stm->sw_nmasters; i++) 6917bd1d409SAlexander Shishkin stp_master_free(stm, i); 6927bd1d409SAlexander Shishkin 6937bd1d409SAlexander Shishkin device_unregister(&stm->dev); 6947bd1d409SAlexander Shishkin stm_data->stm = NULL; 6957bd1d409SAlexander Shishkin } 6967bd1d409SAlexander Shishkin EXPORT_SYMBOL_GPL(stm_unregister_device); 6977bd1d409SAlexander Shishkin 698c74f7e82SAlexander Shishkin /* 699c74f7e82SAlexander Shishkin * stm::link_list access serialization uses a spinlock and a mutex; holding 700c74f7e82SAlexander Shishkin * either of them guarantees that the list is stable; modification requires 701c74f7e82SAlexander Shishkin * holding both of them. 702c74f7e82SAlexander Shishkin * 703c74f7e82SAlexander Shishkin * Lock ordering is as follows: 704c74f7e82SAlexander Shishkin * stm::link_mutex 705c74f7e82SAlexander Shishkin * stm::link_lock 706c74f7e82SAlexander Shishkin * src::link_lock 707c74f7e82SAlexander Shishkin */ 708c74f7e82SAlexander Shishkin 7097bd1d409SAlexander Shishkin /** 7107bd1d409SAlexander Shishkin * stm_source_link_add() - connect an stm_source device to an stm device 7117bd1d409SAlexander Shishkin * @src: stm_source device 7127bd1d409SAlexander Shishkin * @stm: stm device 7137bd1d409SAlexander Shishkin * 7147bd1d409SAlexander Shishkin * This function establishes a link from stm_source to an stm device so that 7157bd1d409SAlexander Shishkin * the former can send out trace data to the latter. 7167bd1d409SAlexander Shishkin * 7177bd1d409SAlexander Shishkin * Return: 0 on success, -errno otherwise. 7187bd1d409SAlexander Shishkin */ 7197bd1d409SAlexander Shishkin static int stm_source_link_add(struct stm_source_device *src, 7207bd1d409SAlexander Shishkin struct stm_device *stm) 7217bd1d409SAlexander Shishkin { 7227bd1d409SAlexander Shishkin char *id; 7237bd1d409SAlexander Shishkin int err; 7247bd1d409SAlexander Shishkin 725c74f7e82SAlexander Shishkin mutex_lock(&stm->link_mutex); 7267bd1d409SAlexander Shishkin spin_lock(&stm->link_lock); 7277bd1d409SAlexander Shishkin spin_lock(&src->link_lock); 7287bd1d409SAlexander Shishkin 7297bd1d409SAlexander Shishkin /* src->link is dereferenced under stm_source_srcu but not the list */ 7307bd1d409SAlexander Shishkin rcu_assign_pointer(src->link, stm); 7317bd1d409SAlexander Shishkin list_add_tail(&src->link_entry, &stm->link_list); 7327bd1d409SAlexander Shishkin 7337bd1d409SAlexander Shishkin spin_unlock(&src->link_lock); 7347bd1d409SAlexander Shishkin spin_unlock(&stm->link_lock); 735c74f7e82SAlexander Shishkin mutex_unlock(&stm->link_mutex); 7367bd1d409SAlexander Shishkin 7377bd1d409SAlexander Shishkin id = kstrdup(src->data->name, GFP_KERNEL); 7387bd1d409SAlexander Shishkin if (id) { 7397bd1d409SAlexander Shishkin src->policy_node = 7407bd1d409SAlexander Shishkin stp_policy_node_lookup(stm, id); 7417bd1d409SAlexander Shishkin 7427bd1d409SAlexander Shishkin kfree(id); 7437bd1d409SAlexander Shishkin } 7447bd1d409SAlexander Shishkin 7457bd1d409SAlexander Shishkin err = stm_output_assign(stm, src->data->nr_chans, 7467bd1d409SAlexander Shishkin src->policy_node, &src->output); 7477bd1d409SAlexander Shishkin 7487bd1d409SAlexander Shishkin if (src->policy_node) 7497bd1d409SAlexander Shishkin stp_policy_node_put(src->policy_node); 7507bd1d409SAlexander Shishkin 7517bd1d409SAlexander Shishkin if (err) 7527bd1d409SAlexander Shishkin goto fail_detach; 7537bd1d409SAlexander Shishkin 7547bd1d409SAlexander Shishkin /* this is to notify the STM device that a new link has been made */ 7557bd1d409SAlexander Shishkin if (stm->data->link) 7567bd1d409SAlexander Shishkin err = stm->data->link(stm->data, src->output.master, 7577bd1d409SAlexander Shishkin src->output.channel); 7587bd1d409SAlexander Shishkin 7597bd1d409SAlexander Shishkin if (err) 7607bd1d409SAlexander Shishkin goto fail_free_output; 7617bd1d409SAlexander Shishkin 7627bd1d409SAlexander Shishkin /* this is to let the source carry out all necessary preparations */ 7637bd1d409SAlexander Shishkin if (src->data->link) 7647bd1d409SAlexander Shishkin src->data->link(src->data); 7657bd1d409SAlexander Shishkin 7667bd1d409SAlexander Shishkin return 0; 7677bd1d409SAlexander Shishkin 7687bd1d409SAlexander Shishkin fail_free_output: 7697bd1d409SAlexander Shishkin stm_output_free(stm, &src->output); 7707bd1d409SAlexander Shishkin stm_put_device(stm); 7717bd1d409SAlexander Shishkin 7727bd1d409SAlexander Shishkin fail_detach: 773c74f7e82SAlexander Shishkin mutex_lock(&stm->link_mutex); 7747bd1d409SAlexander Shishkin spin_lock(&stm->link_lock); 7757bd1d409SAlexander Shishkin spin_lock(&src->link_lock); 7767bd1d409SAlexander Shishkin 7777bd1d409SAlexander Shishkin rcu_assign_pointer(src->link, NULL); 7787bd1d409SAlexander Shishkin list_del_init(&src->link_entry); 7797bd1d409SAlexander Shishkin 7807bd1d409SAlexander Shishkin spin_unlock(&src->link_lock); 7817bd1d409SAlexander Shishkin spin_unlock(&stm->link_lock); 782c74f7e82SAlexander Shishkin mutex_unlock(&stm->link_mutex); 7837bd1d409SAlexander Shishkin 7847bd1d409SAlexander Shishkin return err; 7857bd1d409SAlexander Shishkin } 7867bd1d409SAlexander Shishkin 7877bd1d409SAlexander Shishkin /** 7887bd1d409SAlexander Shishkin * __stm_source_link_drop() - detach stm_source from an stm device 7897bd1d409SAlexander Shishkin * @src: stm_source device 7907bd1d409SAlexander Shishkin * @stm: stm device 7917bd1d409SAlexander Shishkin * 7927bd1d409SAlexander Shishkin * If @stm is @src::link, disconnect them from one another and put the 7937bd1d409SAlexander Shishkin * reference on the @stm device. 7947bd1d409SAlexander Shishkin * 795c74f7e82SAlexander Shishkin * Caller must hold stm::link_mutex. 7967bd1d409SAlexander Shishkin */ 7977bd1d409SAlexander Shishkin static void __stm_source_link_drop(struct stm_source_device *src, 7987bd1d409SAlexander Shishkin struct stm_device *stm) 7997bd1d409SAlexander Shishkin { 8000df771deSAlexander Shishkin struct stm_device *link; 8010df771deSAlexander Shishkin 802c74f7e82SAlexander Shishkin lockdep_assert_held(&stm->link_mutex); 803c74f7e82SAlexander Shishkin 804c74f7e82SAlexander Shishkin if (src->data->unlink) 805c74f7e82SAlexander Shishkin src->data->unlink(src->data); 806c74f7e82SAlexander Shishkin 807c74f7e82SAlexander Shishkin /* for stm::link_list modification, we hold both mutex and spinlock */ 808c74f7e82SAlexander Shishkin spin_lock(&stm->link_lock); 8097bd1d409SAlexander Shishkin spin_lock(&src->link_lock); 8100df771deSAlexander Shishkin link = srcu_dereference_check(src->link, &stm_source_srcu, 1); 8110df771deSAlexander Shishkin if (WARN_ON_ONCE(link != stm)) { 8127bd1d409SAlexander Shishkin spin_unlock(&src->link_lock); 8137bd1d409SAlexander Shishkin return; 8147bd1d409SAlexander Shishkin } 8157bd1d409SAlexander Shishkin 8160df771deSAlexander Shishkin stm_output_free(link, &src->output); 8177bd1d409SAlexander Shishkin list_del_init(&src->link_entry); 8187bd1d409SAlexander Shishkin /* matches stm_find_device() from stm_source_link_store() */ 8190df771deSAlexander Shishkin stm_put_device(link); 8207bd1d409SAlexander Shishkin rcu_assign_pointer(src->link, NULL); 8217bd1d409SAlexander Shishkin 8227bd1d409SAlexander Shishkin spin_unlock(&src->link_lock); 823c74f7e82SAlexander Shishkin spin_unlock(&stm->link_lock); 8247bd1d409SAlexander Shishkin } 8257bd1d409SAlexander Shishkin 8267bd1d409SAlexander Shishkin /** 8277bd1d409SAlexander Shishkin * stm_source_link_drop() - detach stm_source from its stm device 8287bd1d409SAlexander Shishkin * @src: stm_source device 8297bd1d409SAlexander Shishkin * 8307bd1d409SAlexander Shishkin * Unlinking means disconnecting from source's STM device; after this 8317bd1d409SAlexander Shishkin * writes will be unsuccessful until it is linked to a new STM device. 8327bd1d409SAlexander Shishkin * 8337bd1d409SAlexander Shishkin * This will happen on "stm_source_link" sysfs attribute write to undo 8347bd1d409SAlexander Shishkin * the existing link (if any), or on linked STM device's de-registration. 8357bd1d409SAlexander Shishkin */ 8367bd1d409SAlexander Shishkin static void stm_source_link_drop(struct stm_source_device *src) 8377bd1d409SAlexander Shishkin { 8387bd1d409SAlexander Shishkin struct stm_device *stm; 8397bd1d409SAlexander Shishkin int idx; 8407bd1d409SAlexander Shishkin 8417bd1d409SAlexander Shishkin idx = srcu_read_lock(&stm_source_srcu); 8427bd1d409SAlexander Shishkin stm = srcu_dereference(src->link, &stm_source_srcu); 8437bd1d409SAlexander Shishkin 8447bd1d409SAlexander Shishkin if (stm) { 845c74f7e82SAlexander Shishkin mutex_lock(&stm->link_mutex); 8467bd1d409SAlexander Shishkin __stm_source_link_drop(src, stm); 847c74f7e82SAlexander Shishkin mutex_unlock(&stm->link_mutex); 8487bd1d409SAlexander Shishkin } 8497bd1d409SAlexander Shishkin 8507bd1d409SAlexander Shishkin srcu_read_unlock(&stm_source_srcu, idx); 8517bd1d409SAlexander Shishkin } 8527bd1d409SAlexander Shishkin 8537bd1d409SAlexander Shishkin static ssize_t stm_source_link_show(struct device *dev, 8547bd1d409SAlexander Shishkin struct device_attribute *attr, 8557bd1d409SAlexander Shishkin char *buf) 8567bd1d409SAlexander Shishkin { 8577bd1d409SAlexander Shishkin struct stm_source_device *src = to_stm_source_device(dev); 8587bd1d409SAlexander Shishkin struct stm_device *stm; 8597bd1d409SAlexander Shishkin int idx, ret; 8607bd1d409SAlexander Shishkin 8617bd1d409SAlexander Shishkin idx = srcu_read_lock(&stm_source_srcu); 8627bd1d409SAlexander Shishkin stm = srcu_dereference(src->link, &stm_source_srcu); 8637bd1d409SAlexander Shishkin ret = sprintf(buf, "%s\n", 8647bd1d409SAlexander Shishkin stm ? dev_name(&stm->dev) : "<none>"); 8657bd1d409SAlexander Shishkin srcu_read_unlock(&stm_source_srcu, idx); 8667bd1d409SAlexander Shishkin 8677bd1d409SAlexander Shishkin return ret; 8687bd1d409SAlexander Shishkin } 8697bd1d409SAlexander Shishkin 8707bd1d409SAlexander Shishkin static ssize_t stm_source_link_store(struct device *dev, 8717bd1d409SAlexander Shishkin struct device_attribute *attr, 8727bd1d409SAlexander Shishkin const char *buf, size_t count) 8737bd1d409SAlexander Shishkin { 8747bd1d409SAlexander Shishkin struct stm_source_device *src = to_stm_source_device(dev); 8757bd1d409SAlexander Shishkin struct stm_device *link; 8767bd1d409SAlexander Shishkin int err; 8777bd1d409SAlexander Shishkin 8787bd1d409SAlexander Shishkin stm_source_link_drop(src); 8797bd1d409SAlexander Shishkin 8807bd1d409SAlexander Shishkin link = stm_find_device(buf); 8817bd1d409SAlexander Shishkin if (!link) 8827bd1d409SAlexander Shishkin return -EINVAL; 8837bd1d409SAlexander Shishkin 8847bd1d409SAlexander Shishkin err = stm_source_link_add(src, link); 8857bd1d409SAlexander Shishkin if (err) 8867bd1d409SAlexander Shishkin stm_put_device(link); 8877bd1d409SAlexander Shishkin 8887bd1d409SAlexander Shishkin return err ? : count; 8897bd1d409SAlexander Shishkin } 8907bd1d409SAlexander Shishkin 8917bd1d409SAlexander Shishkin static DEVICE_ATTR_RW(stm_source_link); 8927bd1d409SAlexander Shishkin 8937bd1d409SAlexander Shishkin static struct attribute *stm_source_attrs[] = { 8947bd1d409SAlexander Shishkin &dev_attr_stm_source_link.attr, 8957bd1d409SAlexander Shishkin NULL, 8967bd1d409SAlexander Shishkin }; 8977bd1d409SAlexander Shishkin 8987bd1d409SAlexander Shishkin ATTRIBUTE_GROUPS(stm_source); 8997bd1d409SAlexander Shishkin 9007bd1d409SAlexander Shishkin static struct class stm_source_class = { 9017bd1d409SAlexander Shishkin .name = "stm_source", 9027bd1d409SAlexander Shishkin .dev_groups = stm_source_groups, 9037bd1d409SAlexander Shishkin }; 9047bd1d409SAlexander Shishkin 9057bd1d409SAlexander Shishkin static void stm_source_device_release(struct device *dev) 9067bd1d409SAlexander Shishkin { 9077bd1d409SAlexander Shishkin struct stm_source_device *src = to_stm_source_device(dev); 9087bd1d409SAlexander Shishkin 9097bd1d409SAlexander Shishkin kfree(src); 9107bd1d409SAlexander Shishkin } 9117bd1d409SAlexander Shishkin 9127bd1d409SAlexander Shishkin /** 9137bd1d409SAlexander Shishkin * stm_source_register_device() - register an stm_source device 9147bd1d409SAlexander Shishkin * @parent: parent device 9157bd1d409SAlexander Shishkin * @data: device description structure 9167bd1d409SAlexander Shishkin * 9177bd1d409SAlexander Shishkin * This will create a device of stm_source class that can write 9187bd1d409SAlexander Shishkin * data to an stm device once linked. 9197bd1d409SAlexander Shishkin * 9207bd1d409SAlexander Shishkin * Return: 0 on success, -errno otherwise. 9217bd1d409SAlexander Shishkin */ 9227bd1d409SAlexander Shishkin int stm_source_register_device(struct device *parent, 9237bd1d409SAlexander Shishkin struct stm_source_data *data) 9247bd1d409SAlexander Shishkin { 9257bd1d409SAlexander Shishkin struct stm_source_device *src; 9267bd1d409SAlexander Shishkin int err; 9277bd1d409SAlexander Shishkin 9287bd1d409SAlexander Shishkin if (!stm_core_up) 9297bd1d409SAlexander Shishkin return -EPROBE_DEFER; 9307bd1d409SAlexander Shishkin 9317bd1d409SAlexander Shishkin src = kzalloc(sizeof(*src), GFP_KERNEL); 9327bd1d409SAlexander Shishkin if (!src) 9337bd1d409SAlexander Shishkin return -ENOMEM; 9347bd1d409SAlexander Shishkin 9357bd1d409SAlexander Shishkin device_initialize(&src->dev); 9367bd1d409SAlexander Shishkin src->dev.class = &stm_source_class; 9377bd1d409SAlexander Shishkin src->dev.parent = parent; 9387bd1d409SAlexander Shishkin src->dev.release = stm_source_device_release; 9397bd1d409SAlexander Shishkin 9407bd1d409SAlexander Shishkin err = kobject_set_name(&src->dev.kobj, "%s", data->name); 9417bd1d409SAlexander Shishkin if (err) 9427bd1d409SAlexander Shishkin goto err; 9437bd1d409SAlexander Shishkin 9447bd1d409SAlexander Shishkin err = device_add(&src->dev); 9457bd1d409SAlexander Shishkin if (err) 9467bd1d409SAlexander Shishkin goto err; 9477bd1d409SAlexander Shishkin 9487bd1d409SAlexander Shishkin spin_lock_init(&src->link_lock); 9497bd1d409SAlexander Shishkin INIT_LIST_HEAD(&src->link_entry); 9507bd1d409SAlexander Shishkin src->data = data; 9517bd1d409SAlexander Shishkin data->src = src; 9527bd1d409SAlexander Shishkin 9537bd1d409SAlexander Shishkin return 0; 9547bd1d409SAlexander Shishkin 9557bd1d409SAlexander Shishkin err: 9567bd1d409SAlexander Shishkin put_device(&src->dev); 9577bd1d409SAlexander Shishkin kfree(src); 9587bd1d409SAlexander Shishkin 9597bd1d409SAlexander Shishkin return err; 9607bd1d409SAlexander Shishkin } 9617bd1d409SAlexander Shishkin EXPORT_SYMBOL_GPL(stm_source_register_device); 9627bd1d409SAlexander Shishkin 9637bd1d409SAlexander Shishkin /** 9647bd1d409SAlexander Shishkin * stm_source_unregister_device() - unregister an stm_source device 9657bd1d409SAlexander Shishkin * @data: device description that was used to register the device 9667bd1d409SAlexander Shishkin * 9677bd1d409SAlexander Shishkin * This will remove a previously created stm_source device from the system. 9687bd1d409SAlexander Shishkin */ 9697bd1d409SAlexander Shishkin void stm_source_unregister_device(struct stm_source_data *data) 9707bd1d409SAlexander Shishkin { 9717bd1d409SAlexander Shishkin struct stm_source_device *src = data->src; 9727bd1d409SAlexander Shishkin 9737bd1d409SAlexander Shishkin stm_source_link_drop(src); 9747bd1d409SAlexander Shishkin 9757bd1d409SAlexander Shishkin device_destroy(&stm_source_class, src->dev.devt); 9767bd1d409SAlexander Shishkin } 9777bd1d409SAlexander Shishkin EXPORT_SYMBOL_GPL(stm_source_unregister_device); 9787bd1d409SAlexander Shishkin 9797bd1d409SAlexander Shishkin int stm_source_write(struct stm_source_data *data, unsigned int chan, 9807bd1d409SAlexander Shishkin const char *buf, size_t count) 9817bd1d409SAlexander Shishkin { 9827bd1d409SAlexander Shishkin struct stm_source_device *src = data->src; 9837bd1d409SAlexander Shishkin struct stm_device *stm; 9847bd1d409SAlexander Shishkin int idx; 9857bd1d409SAlexander Shishkin 9867bd1d409SAlexander Shishkin if (!src->output.nr_chans) 9877bd1d409SAlexander Shishkin return -ENODEV; 9887bd1d409SAlexander Shishkin 9897bd1d409SAlexander Shishkin if (chan >= src->output.nr_chans) 9907bd1d409SAlexander Shishkin return -EINVAL; 9917bd1d409SAlexander Shishkin 9927bd1d409SAlexander Shishkin idx = srcu_read_lock(&stm_source_srcu); 9937bd1d409SAlexander Shishkin 9947bd1d409SAlexander Shishkin stm = srcu_dereference(src->link, &stm_source_srcu); 9957bd1d409SAlexander Shishkin if (stm) 9967bd1d409SAlexander Shishkin stm_write(stm->data, src->output.master, 9977bd1d409SAlexander Shishkin src->output.channel + chan, 9987bd1d409SAlexander Shishkin buf, count); 9997bd1d409SAlexander Shishkin else 10007bd1d409SAlexander Shishkin count = -ENODEV; 10017bd1d409SAlexander Shishkin 10027bd1d409SAlexander Shishkin srcu_read_unlock(&stm_source_srcu, idx); 10037bd1d409SAlexander Shishkin 10047bd1d409SAlexander Shishkin return count; 10057bd1d409SAlexander Shishkin } 10067bd1d409SAlexander Shishkin EXPORT_SYMBOL_GPL(stm_source_write); 10077bd1d409SAlexander Shishkin 10087bd1d409SAlexander Shishkin static int __init stm_core_init(void) 10097bd1d409SAlexander Shishkin { 10107bd1d409SAlexander Shishkin int err; 10117bd1d409SAlexander Shishkin 10127bd1d409SAlexander Shishkin err = class_register(&stm_class); 10137bd1d409SAlexander Shishkin if (err) 10147bd1d409SAlexander Shishkin return err; 10157bd1d409SAlexander Shishkin 10167bd1d409SAlexander Shishkin err = class_register(&stm_source_class); 10177bd1d409SAlexander Shishkin if (err) 10187bd1d409SAlexander Shishkin goto err_stm; 10197bd1d409SAlexander Shishkin 10207bd1d409SAlexander Shishkin err = stp_configfs_init(); 10217bd1d409SAlexander Shishkin if (err) 10227bd1d409SAlexander Shishkin goto err_src; 10237bd1d409SAlexander Shishkin 10247bd1d409SAlexander Shishkin init_srcu_struct(&stm_source_srcu); 10257bd1d409SAlexander Shishkin 10267bd1d409SAlexander Shishkin stm_core_up++; 10277bd1d409SAlexander Shishkin 10287bd1d409SAlexander Shishkin return 0; 10297bd1d409SAlexander Shishkin 10307bd1d409SAlexander Shishkin err_src: 10317bd1d409SAlexander Shishkin class_unregister(&stm_source_class); 10327bd1d409SAlexander Shishkin err_stm: 10337bd1d409SAlexander Shishkin class_unregister(&stm_class); 10347bd1d409SAlexander Shishkin 10357bd1d409SAlexander Shishkin return err; 10367bd1d409SAlexander Shishkin } 10377bd1d409SAlexander Shishkin 10387bd1d409SAlexander Shishkin module_init(stm_core_init); 10397bd1d409SAlexander Shishkin 10407bd1d409SAlexander Shishkin static void __exit stm_core_exit(void) 10417bd1d409SAlexander Shishkin { 10427bd1d409SAlexander Shishkin cleanup_srcu_struct(&stm_source_srcu); 10437bd1d409SAlexander Shishkin class_unregister(&stm_source_class); 10447bd1d409SAlexander Shishkin class_unregister(&stm_class); 10457bd1d409SAlexander Shishkin stp_configfs_exit(); 10467bd1d409SAlexander Shishkin } 10477bd1d409SAlexander Shishkin 10487bd1d409SAlexander Shishkin module_exit(stm_core_exit); 10497bd1d409SAlexander Shishkin 10507bd1d409SAlexander Shishkin MODULE_LICENSE("GPL v2"); 10517bd1d409SAlexander Shishkin MODULE_DESCRIPTION("System Trace Module device class"); 10527bd1d409SAlexander Shishkin MODULE_AUTHOR("Alexander Shishkin <alexander.shishkin@linux.intel.com>"); 1053