19ea393d8SAlexander Shishkin // SPDX-License-Identifier: GPL-2.0 27bd1d409SAlexander Shishkin /* 37bd1d409SAlexander Shishkin * System Trace Module (STM) infrastructure 47bd1d409SAlexander Shishkin * Copyright (c) 2014, Intel Corporation. 57bd1d409SAlexander Shishkin * 67bd1d409SAlexander Shishkin * STM class implements generic infrastructure for System Trace Module devices 77bd1d409SAlexander Shishkin * as defined in MIPI STPv2 specification. 87bd1d409SAlexander Shishkin */ 97bd1d409SAlexander Shishkin 108e0469a4SAlexander Shishkin #include <linux/pm_runtime.h> 117bd1d409SAlexander Shishkin #include <linux/uaccess.h> 127bd1d409SAlexander Shishkin #include <linux/kernel.h> 137bd1d409SAlexander Shishkin #include <linux/module.h> 147bd1d409SAlexander Shishkin #include <linux/device.h> 157bd1d409SAlexander Shishkin #include <linux/compat.h> 167bd1d409SAlexander Shishkin #include <linux/kdev_t.h> 177bd1d409SAlexander Shishkin #include <linux/srcu.h> 187bd1d409SAlexander Shishkin #include <linux/slab.h> 197bd1d409SAlexander Shishkin #include <linux/stm.h> 207bd1d409SAlexander Shishkin #include <linux/fs.h> 217bd1d409SAlexander Shishkin #include <linux/mm.h> 22806e3087SGreg Kroah-Hartman #include <linux/vmalloc.h> 237bd1d409SAlexander Shishkin #include "stm.h" 247bd1d409SAlexander Shishkin 257bd1d409SAlexander Shishkin #include <uapi/linux/stm.h> 267bd1d409SAlexander Shishkin 277bd1d409SAlexander Shishkin static unsigned int stm_core_up; 287bd1d409SAlexander Shishkin 297bd1d409SAlexander Shishkin /* 307bd1d409SAlexander Shishkin * The SRCU here makes sure that STM device doesn't disappear from under a 317bd1d409SAlexander Shishkin * stm_source_write() caller, which may want to have as little overhead as 327bd1d409SAlexander Shishkin * possible. 337bd1d409SAlexander Shishkin */ 347bd1d409SAlexander Shishkin static struct srcu_struct stm_source_srcu; 357bd1d409SAlexander Shishkin 367bd1d409SAlexander Shishkin static ssize_t masters_show(struct device *dev, 377bd1d409SAlexander Shishkin struct device_attribute *attr, 387bd1d409SAlexander Shishkin char *buf) 397bd1d409SAlexander Shishkin { 407bd1d409SAlexander Shishkin struct stm_device *stm = to_stm_device(dev); 417bd1d409SAlexander Shishkin int ret; 427bd1d409SAlexander Shishkin 437bd1d409SAlexander Shishkin ret = sprintf(buf, "%u %u\n", stm->data->sw_start, stm->data->sw_end); 447bd1d409SAlexander Shishkin 457bd1d409SAlexander Shishkin return ret; 467bd1d409SAlexander Shishkin } 477bd1d409SAlexander Shishkin 487bd1d409SAlexander Shishkin static DEVICE_ATTR_RO(masters); 497bd1d409SAlexander Shishkin 507bd1d409SAlexander Shishkin static ssize_t channels_show(struct device *dev, 517bd1d409SAlexander Shishkin struct device_attribute *attr, 527bd1d409SAlexander Shishkin char *buf) 537bd1d409SAlexander Shishkin { 547bd1d409SAlexander Shishkin struct stm_device *stm = to_stm_device(dev); 557bd1d409SAlexander Shishkin int ret; 567bd1d409SAlexander Shishkin 577bd1d409SAlexander Shishkin ret = sprintf(buf, "%u\n", stm->data->sw_nchannels); 587bd1d409SAlexander Shishkin 597bd1d409SAlexander Shishkin return ret; 607bd1d409SAlexander Shishkin } 617bd1d409SAlexander Shishkin 627bd1d409SAlexander Shishkin static DEVICE_ATTR_RO(channels); 637bd1d409SAlexander Shishkin 648e996a28SAlexander Shishkin static ssize_t hw_override_show(struct device *dev, 658e996a28SAlexander Shishkin struct device_attribute *attr, 668e996a28SAlexander Shishkin char *buf) 678e996a28SAlexander Shishkin { 688e996a28SAlexander Shishkin struct stm_device *stm = to_stm_device(dev); 698e996a28SAlexander Shishkin int ret; 708e996a28SAlexander Shishkin 718e996a28SAlexander Shishkin ret = sprintf(buf, "%u\n", stm->data->hw_override); 728e996a28SAlexander Shishkin 738e996a28SAlexander Shishkin return ret; 748e996a28SAlexander Shishkin } 758e996a28SAlexander Shishkin 768e996a28SAlexander Shishkin static DEVICE_ATTR_RO(hw_override); 778e996a28SAlexander Shishkin 787bd1d409SAlexander Shishkin static struct attribute *stm_attrs[] = { 797bd1d409SAlexander Shishkin &dev_attr_masters.attr, 807bd1d409SAlexander Shishkin &dev_attr_channels.attr, 818e996a28SAlexander Shishkin &dev_attr_hw_override.attr, 827bd1d409SAlexander Shishkin NULL, 837bd1d409SAlexander Shishkin }; 847bd1d409SAlexander Shishkin 857bd1d409SAlexander Shishkin ATTRIBUTE_GROUPS(stm); 867bd1d409SAlexander Shishkin 877bd1d409SAlexander Shishkin static struct class stm_class = { 887bd1d409SAlexander Shishkin .name = "stm", 897bd1d409SAlexander Shishkin .dev_groups = stm_groups, 907bd1d409SAlexander Shishkin }; 917bd1d409SAlexander Shishkin 927bd1d409SAlexander Shishkin static int stm_dev_match(struct device *dev, const void *data) 937bd1d409SAlexander Shishkin { 947bd1d409SAlexander Shishkin const char *name = data; 957bd1d409SAlexander Shishkin 967bd1d409SAlexander Shishkin return sysfs_streq(name, dev_name(dev)); 977bd1d409SAlexander Shishkin } 987bd1d409SAlexander Shishkin 997bd1d409SAlexander Shishkin /** 1007bd1d409SAlexander Shishkin * stm_find_device() - find stm device by name 1017bd1d409SAlexander Shishkin * @buf: character buffer containing the name 1027bd1d409SAlexander Shishkin * 1037bd1d409SAlexander Shishkin * This is called when either policy gets assigned to an stm device or an 1047bd1d409SAlexander Shishkin * stm_source device gets linked to an stm device. 1057bd1d409SAlexander Shishkin * 1067bd1d409SAlexander Shishkin * This grabs device's reference (get_device()) and module reference, both 1077bd1d409SAlexander Shishkin * of which the calling path needs to make sure to drop with stm_put_device(). 1087bd1d409SAlexander Shishkin * 1097bd1d409SAlexander Shishkin * Return: stm device pointer or null if lookup failed. 1107bd1d409SAlexander Shishkin */ 1117bd1d409SAlexander Shishkin struct stm_device *stm_find_device(const char *buf) 1127bd1d409SAlexander Shishkin { 1137bd1d409SAlexander Shishkin struct stm_device *stm; 1147bd1d409SAlexander Shishkin struct device *dev; 1157bd1d409SAlexander Shishkin 1167bd1d409SAlexander Shishkin if (!stm_core_up) 1177bd1d409SAlexander Shishkin return NULL; 1187bd1d409SAlexander Shishkin 1197bd1d409SAlexander Shishkin dev = class_find_device(&stm_class, NULL, buf, stm_dev_match); 1207bd1d409SAlexander Shishkin if (!dev) 1217bd1d409SAlexander Shishkin return NULL; 1227bd1d409SAlexander Shishkin 1237bd1d409SAlexander Shishkin stm = to_stm_device(dev); 1247bd1d409SAlexander Shishkin if (!try_module_get(stm->owner)) { 125f7c81c71SAlexander Shishkin /* matches class_find_device() above */ 1267bd1d409SAlexander Shishkin put_device(dev); 1277bd1d409SAlexander Shishkin return NULL; 1287bd1d409SAlexander Shishkin } 1297bd1d409SAlexander Shishkin 1307bd1d409SAlexander Shishkin return stm; 1317bd1d409SAlexander Shishkin } 1327bd1d409SAlexander Shishkin 1337bd1d409SAlexander Shishkin /** 1347bd1d409SAlexander Shishkin * stm_put_device() - drop references on the stm device 1357bd1d409SAlexander Shishkin * @stm: stm device, previously acquired by stm_find_device() 1367bd1d409SAlexander Shishkin * 1377bd1d409SAlexander Shishkin * This drops the module reference and device reference taken by 138f7c81c71SAlexander Shishkin * stm_find_device() or stm_char_open(). 1397bd1d409SAlexander Shishkin */ 1407bd1d409SAlexander Shishkin void stm_put_device(struct stm_device *stm) 1417bd1d409SAlexander Shishkin { 1427bd1d409SAlexander Shishkin module_put(stm->owner); 1437bd1d409SAlexander Shishkin put_device(&stm->dev); 1447bd1d409SAlexander Shishkin } 1457bd1d409SAlexander Shishkin 1467bd1d409SAlexander Shishkin /* 1477bd1d409SAlexander Shishkin * Internally we only care about software-writable masters here, that is the 1487bd1d409SAlexander Shishkin * ones in the range [stm_data->sw_start..stm_data..sw_end], however we need 1497bd1d409SAlexander Shishkin * original master numbers to be visible externally, since they are the ones 1507bd1d409SAlexander Shishkin * that will appear in the STP stream. Thus, the internal bookkeeping uses 1517bd1d409SAlexander Shishkin * $master - stm_data->sw_start to reference master descriptors and such. 1527bd1d409SAlexander Shishkin */ 1537bd1d409SAlexander Shishkin 1547bd1d409SAlexander Shishkin #define __stm_master(_s, _m) \ 1557bd1d409SAlexander Shishkin ((_s)->masters[(_m) - (_s)->data->sw_start]) 1567bd1d409SAlexander Shishkin 1577bd1d409SAlexander Shishkin static inline struct stp_master * 1587bd1d409SAlexander Shishkin stm_master(struct stm_device *stm, unsigned int idx) 1597bd1d409SAlexander Shishkin { 1607bd1d409SAlexander Shishkin if (idx < stm->data->sw_start || idx > stm->data->sw_end) 1617bd1d409SAlexander Shishkin return NULL; 1627bd1d409SAlexander Shishkin 1637bd1d409SAlexander Shishkin return __stm_master(stm, idx); 1647bd1d409SAlexander Shishkin } 1657bd1d409SAlexander Shishkin 1667bd1d409SAlexander Shishkin static int stp_master_alloc(struct stm_device *stm, unsigned int idx) 1677bd1d409SAlexander Shishkin { 1687bd1d409SAlexander Shishkin struct stp_master *master; 1697bd1d409SAlexander Shishkin size_t size; 1707bd1d409SAlexander Shishkin 1717bd1d409SAlexander Shishkin size = ALIGN(stm->data->sw_nchannels, 8) / 8; 1727bd1d409SAlexander Shishkin size += sizeof(struct stp_master); 1737bd1d409SAlexander Shishkin master = kzalloc(size, GFP_ATOMIC); 1747bd1d409SAlexander Shishkin if (!master) 1757bd1d409SAlexander Shishkin return -ENOMEM; 1767bd1d409SAlexander Shishkin 1777bd1d409SAlexander Shishkin master->nr_free = stm->data->sw_nchannels; 1787bd1d409SAlexander Shishkin __stm_master(stm, idx) = master; 1797bd1d409SAlexander Shishkin 1807bd1d409SAlexander Shishkin return 0; 1817bd1d409SAlexander Shishkin } 1827bd1d409SAlexander Shishkin 1837bd1d409SAlexander Shishkin static void stp_master_free(struct stm_device *stm, unsigned int idx) 1847bd1d409SAlexander Shishkin { 1857bd1d409SAlexander Shishkin struct stp_master *master = stm_master(stm, idx); 1867bd1d409SAlexander Shishkin 1877bd1d409SAlexander Shishkin if (!master) 1887bd1d409SAlexander Shishkin return; 1897bd1d409SAlexander Shishkin 1907bd1d409SAlexander Shishkin __stm_master(stm, idx) = NULL; 1917bd1d409SAlexander Shishkin kfree(master); 1927bd1d409SAlexander Shishkin } 1937bd1d409SAlexander Shishkin 1947bd1d409SAlexander Shishkin static void stm_output_claim(struct stm_device *stm, struct stm_output *output) 1957bd1d409SAlexander Shishkin { 1967bd1d409SAlexander Shishkin struct stp_master *master = stm_master(stm, output->master); 1977bd1d409SAlexander Shishkin 198cde4ad83SAlexander Shishkin lockdep_assert_held(&stm->mc_lock); 199cde4ad83SAlexander Shishkin lockdep_assert_held(&output->lock); 200cde4ad83SAlexander Shishkin 2017bd1d409SAlexander Shishkin if (WARN_ON_ONCE(master->nr_free < output->nr_chans)) 2027bd1d409SAlexander Shishkin return; 2037bd1d409SAlexander Shishkin 2047bd1d409SAlexander Shishkin bitmap_allocate_region(&master->chan_map[0], output->channel, 2057bd1d409SAlexander Shishkin ilog2(output->nr_chans)); 2067bd1d409SAlexander Shishkin 2077bd1d409SAlexander Shishkin master->nr_free -= output->nr_chans; 2087bd1d409SAlexander Shishkin } 2097bd1d409SAlexander Shishkin 2107bd1d409SAlexander Shishkin static void 2117bd1d409SAlexander Shishkin stm_output_disclaim(struct stm_device *stm, struct stm_output *output) 2127bd1d409SAlexander Shishkin { 2137bd1d409SAlexander Shishkin struct stp_master *master = stm_master(stm, output->master); 2147bd1d409SAlexander Shishkin 215cde4ad83SAlexander Shishkin lockdep_assert_held(&stm->mc_lock); 216cde4ad83SAlexander Shishkin lockdep_assert_held(&output->lock); 217cde4ad83SAlexander Shishkin 2187bd1d409SAlexander Shishkin bitmap_release_region(&master->chan_map[0], output->channel, 2197bd1d409SAlexander Shishkin ilog2(output->nr_chans)); 2207bd1d409SAlexander Shishkin 2217bd1d409SAlexander Shishkin output->nr_chans = 0; 2227bd1d409SAlexander Shishkin master->nr_free += output->nr_chans; 2237bd1d409SAlexander Shishkin } 2247bd1d409SAlexander Shishkin 2257bd1d409SAlexander Shishkin /* 2267bd1d409SAlexander Shishkin * This is like bitmap_find_free_region(), except it can ignore @start bits 2277bd1d409SAlexander Shishkin * at the beginning. 2287bd1d409SAlexander Shishkin */ 2297bd1d409SAlexander Shishkin static int find_free_channels(unsigned long *bitmap, unsigned int start, 2307bd1d409SAlexander Shishkin unsigned int end, unsigned int width) 2317bd1d409SAlexander Shishkin { 2327bd1d409SAlexander Shishkin unsigned int pos; 2337bd1d409SAlexander Shishkin int i; 2347bd1d409SAlexander Shishkin 2357bd1d409SAlexander Shishkin for (pos = start; pos < end + 1; pos = ALIGN(pos, width)) { 2367bd1d409SAlexander Shishkin pos = find_next_zero_bit(bitmap, end + 1, pos); 2377bd1d409SAlexander Shishkin if (pos + width > end + 1) 2387bd1d409SAlexander Shishkin break; 2397bd1d409SAlexander Shishkin 2407bd1d409SAlexander Shishkin if (pos & (width - 1)) 2417bd1d409SAlexander Shishkin continue; 2427bd1d409SAlexander Shishkin 2437bd1d409SAlexander Shishkin for (i = 1; i < width && !test_bit(pos + i, bitmap); i++) 2447bd1d409SAlexander Shishkin ; 2457bd1d409SAlexander Shishkin if (i == width) 2467bd1d409SAlexander Shishkin return pos; 2477bd1d409SAlexander Shishkin } 2487bd1d409SAlexander Shishkin 2497bd1d409SAlexander Shishkin return -1; 2507bd1d409SAlexander Shishkin } 2517bd1d409SAlexander Shishkin 252f45f40adSLucas Tanure static int 2537bd1d409SAlexander Shishkin stm_find_master_chan(struct stm_device *stm, unsigned int width, 2547bd1d409SAlexander Shishkin unsigned int *mstart, unsigned int mend, 2557bd1d409SAlexander Shishkin unsigned int *cstart, unsigned int cend) 2567bd1d409SAlexander Shishkin { 2577bd1d409SAlexander Shishkin struct stp_master *master; 2587bd1d409SAlexander Shishkin unsigned int midx; 2597bd1d409SAlexander Shishkin int pos, err; 2607bd1d409SAlexander Shishkin 2617bd1d409SAlexander Shishkin for (midx = *mstart; midx <= mend; midx++) { 2627bd1d409SAlexander Shishkin if (!stm_master(stm, midx)) { 2637bd1d409SAlexander Shishkin err = stp_master_alloc(stm, midx); 2647bd1d409SAlexander Shishkin if (err) 2657bd1d409SAlexander Shishkin return err; 2667bd1d409SAlexander Shishkin } 2677bd1d409SAlexander Shishkin 2687bd1d409SAlexander Shishkin master = stm_master(stm, midx); 2697bd1d409SAlexander Shishkin 2707bd1d409SAlexander Shishkin if (!master->nr_free) 2717bd1d409SAlexander Shishkin continue; 2727bd1d409SAlexander Shishkin 2737bd1d409SAlexander Shishkin pos = find_free_channels(master->chan_map, *cstart, cend, 2747bd1d409SAlexander Shishkin width); 2757bd1d409SAlexander Shishkin if (pos < 0) 2767bd1d409SAlexander Shishkin continue; 2777bd1d409SAlexander Shishkin 2787bd1d409SAlexander Shishkin *mstart = midx; 2797bd1d409SAlexander Shishkin *cstart = pos; 2807bd1d409SAlexander Shishkin return 0; 2817bd1d409SAlexander Shishkin } 2827bd1d409SAlexander Shishkin 2837bd1d409SAlexander Shishkin return -ENOSPC; 2847bd1d409SAlexander Shishkin } 2857bd1d409SAlexander Shishkin 2867bd1d409SAlexander Shishkin static int stm_output_assign(struct stm_device *stm, unsigned int width, 2877bd1d409SAlexander Shishkin struct stp_policy_node *policy_node, 2887bd1d409SAlexander Shishkin struct stm_output *output) 2897bd1d409SAlexander Shishkin { 2907bd1d409SAlexander Shishkin unsigned int midx, cidx, mend, cend; 2917bd1d409SAlexander Shishkin int ret = -EINVAL; 2927bd1d409SAlexander Shishkin 2937bd1d409SAlexander Shishkin if (width > stm->data->sw_nchannels) 2947bd1d409SAlexander Shishkin return -EINVAL; 2957bd1d409SAlexander Shishkin 2967bd1d409SAlexander Shishkin if (policy_node) { 2977bd1d409SAlexander Shishkin stp_policy_node_get_ranges(policy_node, 2987bd1d409SAlexander Shishkin &midx, &mend, &cidx, &cend); 2997bd1d409SAlexander Shishkin } else { 3007bd1d409SAlexander Shishkin midx = stm->data->sw_start; 3017bd1d409SAlexander Shishkin cidx = 0; 3027bd1d409SAlexander Shishkin mend = stm->data->sw_end; 3037bd1d409SAlexander Shishkin cend = stm->data->sw_nchannels - 1; 3047bd1d409SAlexander Shishkin } 3057bd1d409SAlexander Shishkin 3067bd1d409SAlexander Shishkin spin_lock(&stm->mc_lock); 307cde4ad83SAlexander Shishkin spin_lock(&output->lock); 3087bd1d409SAlexander Shishkin /* output is already assigned -- shouldn't happen */ 3097bd1d409SAlexander Shishkin if (WARN_ON_ONCE(output->nr_chans)) 3107bd1d409SAlexander Shishkin goto unlock; 3117bd1d409SAlexander Shishkin 3127bd1d409SAlexander Shishkin ret = stm_find_master_chan(stm, width, &midx, mend, &cidx, cend); 313f45f40adSLucas Tanure if (ret < 0) 3147bd1d409SAlexander Shishkin goto unlock; 3157bd1d409SAlexander Shishkin 3167bd1d409SAlexander Shishkin output->master = midx; 3177bd1d409SAlexander Shishkin output->channel = cidx; 3187bd1d409SAlexander Shishkin output->nr_chans = width; 3197bd1d409SAlexander Shishkin stm_output_claim(stm, output); 3207bd1d409SAlexander Shishkin dev_dbg(&stm->dev, "assigned %u:%u (+%u)\n", midx, cidx, width); 3217bd1d409SAlexander Shishkin 3227bd1d409SAlexander Shishkin ret = 0; 3237bd1d409SAlexander Shishkin unlock: 324cde4ad83SAlexander Shishkin spin_unlock(&output->lock); 3257bd1d409SAlexander Shishkin spin_unlock(&stm->mc_lock); 3267bd1d409SAlexander Shishkin 3277bd1d409SAlexander Shishkin return ret; 3287bd1d409SAlexander Shishkin } 3297bd1d409SAlexander Shishkin 3307bd1d409SAlexander Shishkin static void stm_output_free(struct stm_device *stm, struct stm_output *output) 3317bd1d409SAlexander Shishkin { 3327bd1d409SAlexander Shishkin spin_lock(&stm->mc_lock); 333cde4ad83SAlexander Shishkin spin_lock(&output->lock); 3347bd1d409SAlexander Shishkin if (output->nr_chans) 3357bd1d409SAlexander Shishkin stm_output_disclaim(stm, output); 336cde4ad83SAlexander Shishkin spin_unlock(&output->lock); 3377bd1d409SAlexander Shishkin spin_unlock(&stm->mc_lock); 3387bd1d409SAlexander Shishkin } 3397bd1d409SAlexander Shishkin 340cde4ad83SAlexander Shishkin static void stm_output_init(struct stm_output *output) 341cde4ad83SAlexander Shishkin { 342cde4ad83SAlexander Shishkin spin_lock_init(&output->lock); 343cde4ad83SAlexander Shishkin } 344cde4ad83SAlexander Shishkin 3457bd1d409SAlexander Shishkin static int major_match(struct device *dev, const void *data) 3467bd1d409SAlexander Shishkin { 3477bd1d409SAlexander Shishkin unsigned int major = *(unsigned int *)data; 3487bd1d409SAlexander Shishkin 3497bd1d409SAlexander Shishkin return MAJOR(dev->devt) == major; 3507bd1d409SAlexander Shishkin } 3517bd1d409SAlexander Shishkin 3527bd1d409SAlexander Shishkin static int stm_char_open(struct inode *inode, struct file *file) 3537bd1d409SAlexander Shishkin { 3547bd1d409SAlexander Shishkin struct stm_file *stmf; 3557bd1d409SAlexander Shishkin struct device *dev; 3567bd1d409SAlexander Shishkin unsigned int major = imajor(inode); 357a0ebf519SJohan Hovold int err = -ENOMEM; 3587bd1d409SAlexander Shishkin 3597bd1d409SAlexander Shishkin dev = class_find_device(&stm_class, NULL, &major, major_match); 3607bd1d409SAlexander Shishkin if (!dev) 3617bd1d409SAlexander Shishkin return -ENODEV; 3627bd1d409SAlexander Shishkin 3637bd1d409SAlexander Shishkin stmf = kzalloc(sizeof(*stmf), GFP_KERNEL); 3647bd1d409SAlexander Shishkin if (!stmf) 365a0ebf519SJohan Hovold goto err_put_device; 3667bd1d409SAlexander Shishkin 367a0ebf519SJohan Hovold err = -ENODEV; 368cde4ad83SAlexander Shishkin stm_output_init(&stmf->output); 3697bd1d409SAlexander Shishkin stmf->stm = to_stm_device(dev); 3707bd1d409SAlexander Shishkin 3717bd1d409SAlexander Shishkin if (!try_module_get(stmf->stm->owner)) 3727bd1d409SAlexander Shishkin goto err_free; 3737bd1d409SAlexander Shishkin 3747bd1d409SAlexander Shishkin file->private_data = stmf; 3757bd1d409SAlexander Shishkin 3767bd1d409SAlexander Shishkin return nonseekable_open(inode, file); 3777bd1d409SAlexander Shishkin 3787bd1d409SAlexander Shishkin err_free: 379a0ebf519SJohan Hovold kfree(stmf); 380a0ebf519SJohan Hovold err_put_device: 381f7c81c71SAlexander Shishkin /* matches class_find_device() above */ 382f7c81c71SAlexander Shishkin put_device(dev); 3837bd1d409SAlexander Shishkin 3847bd1d409SAlexander Shishkin return err; 3857bd1d409SAlexander Shishkin } 3867bd1d409SAlexander Shishkin 3877bd1d409SAlexander Shishkin static int stm_char_release(struct inode *inode, struct file *file) 3887bd1d409SAlexander Shishkin { 3897bd1d409SAlexander Shishkin struct stm_file *stmf = file->private_data; 390cc842407SAlexander Shishkin struct stm_device *stm = stmf->stm; 3917bd1d409SAlexander Shishkin 392cc842407SAlexander Shishkin if (stm->data->unlink) 393cc842407SAlexander Shishkin stm->data->unlink(stm->data, stmf->output.master, 394cc842407SAlexander Shishkin stmf->output.channel); 395cc842407SAlexander Shishkin 396cc842407SAlexander Shishkin stm_output_free(stm, &stmf->output); 397f7c81c71SAlexander Shishkin 398f7c81c71SAlexander Shishkin /* 399f7c81c71SAlexander Shishkin * matches the stm_char_open()'s 400f7c81c71SAlexander Shishkin * class_find_device() + try_module_get() 401f7c81c71SAlexander Shishkin */ 402cc842407SAlexander Shishkin stm_put_device(stm); 4037bd1d409SAlexander Shishkin kfree(stmf); 4047bd1d409SAlexander Shishkin 4057bd1d409SAlexander Shishkin return 0; 4067bd1d409SAlexander Shishkin } 4077bd1d409SAlexander Shishkin 4087bd1d409SAlexander Shishkin static int stm_file_assign(struct stm_file *stmf, char *id, unsigned int width) 4097bd1d409SAlexander Shishkin { 4107bd1d409SAlexander Shishkin struct stm_device *stm = stmf->stm; 4117bd1d409SAlexander Shishkin int ret; 4127bd1d409SAlexander Shishkin 4137bd1d409SAlexander Shishkin stmf->policy_node = stp_policy_node_lookup(stm, id); 4147bd1d409SAlexander Shishkin 4157bd1d409SAlexander Shishkin ret = stm_output_assign(stm, width, stmf->policy_node, &stmf->output); 4167bd1d409SAlexander Shishkin 4177bd1d409SAlexander Shishkin if (stmf->policy_node) 4187bd1d409SAlexander Shishkin stp_policy_node_put(stmf->policy_node); 4197bd1d409SAlexander Shishkin 4207bd1d409SAlexander Shishkin return ret; 4217bd1d409SAlexander Shishkin } 4227bd1d409SAlexander Shishkin 4239dfed80dSChunyan Zhang static ssize_t notrace stm_write(struct stm_data *data, unsigned int master, 4247bd1d409SAlexander Shishkin unsigned int channel, const char *buf, size_t count) 4257bd1d409SAlexander Shishkin { 4267bd1d409SAlexander Shishkin unsigned int flags = STP_PACKET_TIMESTAMPED; 4277bd1d409SAlexander Shishkin const unsigned char *p = buf, nil = 0; 4287bd1d409SAlexander Shishkin size_t pos; 4297bd1d409SAlexander Shishkin ssize_t sz; 4307bd1d409SAlexander Shishkin 4317bd1d409SAlexander Shishkin for (pos = 0, p = buf; count > pos; pos += sz, p += sz) { 4327bd1d409SAlexander Shishkin sz = min_t(unsigned int, count - pos, 8); 4337bd1d409SAlexander Shishkin sz = data->packet(data, master, channel, STP_PACKET_DATA, flags, 4347bd1d409SAlexander Shishkin sz, p); 4357bd1d409SAlexander Shishkin flags = 0; 436f8560a9bSAlexander Shishkin 437f8560a9bSAlexander Shishkin if (sz < 0) 438f8560a9bSAlexander Shishkin break; 4397bd1d409SAlexander Shishkin } 4407bd1d409SAlexander Shishkin 4417bd1d409SAlexander Shishkin data->packet(data, master, channel, STP_PACKET_FLAG, 0, 0, &nil); 442f8560a9bSAlexander Shishkin 443f8560a9bSAlexander Shishkin return pos; 4447bd1d409SAlexander Shishkin } 4457bd1d409SAlexander Shishkin 4467bd1d409SAlexander Shishkin static ssize_t stm_char_write(struct file *file, const char __user *buf, 4477bd1d409SAlexander Shishkin size_t count, loff_t *ppos) 4487bd1d409SAlexander Shishkin { 4497bd1d409SAlexander Shishkin struct stm_file *stmf = file->private_data; 4507bd1d409SAlexander Shishkin struct stm_device *stm = stmf->stm; 4517bd1d409SAlexander Shishkin char *kbuf; 4527bd1d409SAlexander Shishkin int err; 4537bd1d409SAlexander Shishkin 454f08b1826SAlexander Shishkin if (count + 1 > PAGE_SIZE) 455f08b1826SAlexander Shishkin count = PAGE_SIZE - 1; 456f08b1826SAlexander Shishkin 4577bd1d409SAlexander Shishkin /* 4587bd1d409SAlexander Shishkin * if no m/c have been assigned to this writer up to this 4597bd1d409SAlexander Shishkin * point, use "default" policy entry 4607bd1d409SAlexander Shishkin */ 4617bd1d409SAlexander Shishkin if (!stmf->output.nr_chans) { 4627bd1d409SAlexander Shishkin err = stm_file_assign(stmf, "default", 1); 4637bd1d409SAlexander Shishkin /* 4647bd1d409SAlexander Shishkin * EBUSY means that somebody else just assigned this 4657bd1d409SAlexander Shishkin * output, which is just fine for write() 4667bd1d409SAlexander Shishkin */ 4677bd1d409SAlexander Shishkin if (err && err != -EBUSY) 4687bd1d409SAlexander Shishkin return err; 4697bd1d409SAlexander Shishkin } 4707bd1d409SAlexander Shishkin 4717bd1d409SAlexander Shishkin kbuf = kmalloc(count + 1, GFP_KERNEL); 4727bd1d409SAlexander Shishkin if (!kbuf) 4737bd1d409SAlexander Shishkin return -ENOMEM; 4747bd1d409SAlexander Shishkin 4757bd1d409SAlexander Shishkin err = copy_from_user(kbuf, buf, count); 4767bd1d409SAlexander Shishkin if (err) { 4777bd1d409SAlexander Shishkin kfree(kbuf); 4787bd1d409SAlexander Shishkin return -EFAULT; 4797bd1d409SAlexander Shishkin } 4807bd1d409SAlexander Shishkin 4818e0469a4SAlexander Shishkin pm_runtime_get_sync(&stm->dev); 4828e0469a4SAlexander Shishkin 483f8560a9bSAlexander Shishkin count = stm_write(stm->data, stmf->output.master, stmf->output.channel, 484f8560a9bSAlexander Shishkin kbuf, count); 4857bd1d409SAlexander Shishkin 4868e0469a4SAlexander Shishkin pm_runtime_mark_last_busy(&stm->dev); 4878e0469a4SAlexander Shishkin pm_runtime_put_autosuspend(&stm->dev); 4887bd1d409SAlexander Shishkin kfree(kbuf); 4897bd1d409SAlexander Shishkin 4907bd1d409SAlexander Shishkin return count; 4917bd1d409SAlexander Shishkin } 4927bd1d409SAlexander Shishkin 4938e0469a4SAlexander Shishkin static void stm_mmap_open(struct vm_area_struct *vma) 4948e0469a4SAlexander Shishkin { 4958e0469a4SAlexander Shishkin struct stm_file *stmf = vma->vm_file->private_data; 4968e0469a4SAlexander Shishkin struct stm_device *stm = stmf->stm; 4978e0469a4SAlexander Shishkin 4988e0469a4SAlexander Shishkin pm_runtime_get(&stm->dev); 4998e0469a4SAlexander Shishkin } 5008e0469a4SAlexander Shishkin 5018e0469a4SAlexander Shishkin static void stm_mmap_close(struct vm_area_struct *vma) 5028e0469a4SAlexander Shishkin { 5038e0469a4SAlexander Shishkin struct stm_file *stmf = vma->vm_file->private_data; 5048e0469a4SAlexander Shishkin struct stm_device *stm = stmf->stm; 5058e0469a4SAlexander Shishkin 5068e0469a4SAlexander Shishkin pm_runtime_mark_last_busy(&stm->dev); 5078e0469a4SAlexander Shishkin pm_runtime_put_autosuspend(&stm->dev); 5088e0469a4SAlexander Shishkin } 5098e0469a4SAlexander Shishkin 5108e0469a4SAlexander Shishkin static const struct vm_operations_struct stm_mmap_vmops = { 5118e0469a4SAlexander Shishkin .open = stm_mmap_open, 5128e0469a4SAlexander Shishkin .close = stm_mmap_close, 5138e0469a4SAlexander Shishkin }; 5148e0469a4SAlexander Shishkin 5157bd1d409SAlexander Shishkin static int stm_char_mmap(struct file *file, struct vm_area_struct *vma) 5167bd1d409SAlexander Shishkin { 5177bd1d409SAlexander Shishkin struct stm_file *stmf = file->private_data; 5187bd1d409SAlexander Shishkin struct stm_device *stm = stmf->stm; 5197bd1d409SAlexander Shishkin unsigned long size, phys; 5207bd1d409SAlexander Shishkin 5217bd1d409SAlexander Shishkin if (!stm->data->mmio_addr) 5227bd1d409SAlexander Shishkin return -EOPNOTSUPP; 5237bd1d409SAlexander Shishkin 5247bd1d409SAlexander Shishkin if (vma->vm_pgoff) 5257bd1d409SAlexander Shishkin return -EINVAL; 5267bd1d409SAlexander Shishkin 5277bd1d409SAlexander Shishkin size = vma->vm_end - vma->vm_start; 5287bd1d409SAlexander Shishkin 5297bd1d409SAlexander Shishkin if (stmf->output.nr_chans * stm->data->sw_mmiosz != size) 5307bd1d409SAlexander Shishkin return -EINVAL; 5317bd1d409SAlexander Shishkin 5327bd1d409SAlexander Shishkin phys = stm->data->mmio_addr(stm->data, stmf->output.master, 5337bd1d409SAlexander Shishkin stmf->output.channel, 5347bd1d409SAlexander Shishkin stmf->output.nr_chans); 5357bd1d409SAlexander Shishkin 5367bd1d409SAlexander Shishkin if (!phys) 5377bd1d409SAlexander Shishkin return -EINVAL; 5387bd1d409SAlexander Shishkin 5398e0469a4SAlexander Shishkin pm_runtime_get_sync(&stm->dev); 5408e0469a4SAlexander Shishkin 5417bd1d409SAlexander Shishkin vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot); 5427bd1d409SAlexander Shishkin vma->vm_flags |= VM_IO | VM_DONTEXPAND | VM_DONTDUMP; 5438e0469a4SAlexander Shishkin vma->vm_ops = &stm_mmap_vmops; 5447bd1d409SAlexander Shishkin vm_iomap_memory(vma, phys, size); 5457bd1d409SAlexander Shishkin 5467bd1d409SAlexander Shishkin return 0; 5477bd1d409SAlexander Shishkin } 5487bd1d409SAlexander Shishkin 5497bd1d409SAlexander Shishkin static int stm_char_policy_set_ioctl(struct stm_file *stmf, void __user *arg) 5507bd1d409SAlexander Shishkin { 5517bd1d409SAlexander Shishkin struct stm_device *stm = stmf->stm; 5527bd1d409SAlexander Shishkin struct stp_policy_id *id; 5537bd1d409SAlexander Shishkin int ret = -EINVAL; 5547bd1d409SAlexander Shishkin u32 size; 5557bd1d409SAlexander Shishkin 5567bd1d409SAlexander Shishkin if (stmf->output.nr_chans) 5577bd1d409SAlexander Shishkin return -EBUSY; 5587bd1d409SAlexander Shishkin 5597bd1d409SAlexander Shishkin if (copy_from_user(&size, arg, sizeof(size))) 5607bd1d409SAlexander Shishkin return -EFAULT; 5617bd1d409SAlexander Shishkin 56271c488f3SDan Carpenter if (size < sizeof(*id) || size >= PATH_MAX + sizeof(*id)) 5637bd1d409SAlexander Shishkin return -EINVAL; 5647bd1d409SAlexander Shishkin 5657bd1d409SAlexander Shishkin /* 5667bd1d409SAlexander Shishkin * size + 1 to make sure the .id string at the bottom is terminated, 5677bd1d409SAlexander Shishkin * which is also why memdup_user() is not useful here 5687bd1d409SAlexander Shishkin */ 5697bd1d409SAlexander Shishkin id = kzalloc(size + 1, GFP_KERNEL); 5707bd1d409SAlexander Shishkin if (!id) 5717bd1d409SAlexander Shishkin return -ENOMEM; 5727bd1d409SAlexander Shishkin 5737bd1d409SAlexander Shishkin if (copy_from_user(id, arg, size)) { 5747bd1d409SAlexander Shishkin ret = -EFAULT; 5757bd1d409SAlexander Shishkin goto err_free; 5767bd1d409SAlexander Shishkin } 5777bd1d409SAlexander Shishkin 5787bd1d409SAlexander Shishkin if (id->__reserved_0 || id->__reserved_1) 5797bd1d409SAlexander Shishkin goto err_free; 5807bd1d409SAlexander Shishkin 5817bd1d409SAlexander Shishkin if (id->width < 1 || 5827bd1d409SAlexander Shishkin id->width > PAGE_SIZE / stm->data->sw_mmiosz) 5837bd1d409SAlexander Shishkin goto err_free; 5847bd1d409SAlexander Shishkin 5857bd1d409SAlexander Shishkin ret = stm_file_assign(stmf, id->id, id->width); 5867bd1d409SAlexander Shishkin if (ret) 5877bd1d409SAlexander Shishkin goto err_free; 5887bd1d409SAlexander Shishkin 5897bd1d409SAlexander Shishkin if (stm->data->link) 5907bd1d409SAlexander Shishkin ret = stm->data->link(stm->data, stmf->output.master, 5917bd1d409SAlexander Shishkin stmf->output.channel); 5927bd1d409SAlexander Shishkin 593f7c81c71SAlexander Shishkin if (ret) 5947bd1d409SAlexander Shishkin stm_output_free(stmf->stm, &stmf->output); 5957bd1d409SAlexander Shishkin 5967bd1d409SAlexander Shishkin err_free: 5977bd1d409SAlexander Shishkin kfree(id); 5987bd1d409SAlexander Shishkin 5997bd1d409SAlexander Shishkin return ret; 6007bd1d409SAlexander Shishkin } 6017bd1d409SAlexander Shishkin 6027bd1d409SAlexander Shishkin static int stm_char_policy_get_ioctl(struct stm_file *stmf, void __user *arg) 6037bd1d409SAlexander Shishkin { 6047bd1d409SAlexander Shishkin struct stp_policy_id id = { 6057bd1d409SAlexander Shishkin .size = sizeof(id), 6067bd1d409SAlexander Shishkin .master = stmf->output.master, 6077bd1d409SAlexander Shishkin .channel = stmf->output.channel, 6087bd1d409SAlexander Shishkin .width = stmf->output.nr_chans, 6097bd1d409SAlexander Shishkin .__reserved_0 = 0, 6107bd1d409SAlexander Shishkin .__reserved_1 = 0, 6117bd1d409SAlexander Shishkin }; 6127bd1d409SAlexander Shishkin 6137bd1d409SAlexander Shishkin return copy_to_user(arg, &id, id.size) ? -EFAULT : 0; 6147bd1d409SAlexander Shishkin } 6157bd1d409SAlexander Shishkin 6167bd1d409SAlexander Shishkin static long 6177bd1d409SAlexander Shishkin stm_char_ioctl(struct file *file, unsigned int cmd, unsigned long arg) 6187bd1d409SAlexander Shishkin { 6197bd1d409SAlexander Shishkin struct stm_file *stmf = file->private_data; 6207bd1d409SAlexander Shishkin struct stm_data *stm_data = stmf->stm->data; 6217bd1d409SAlexander Shishkin int err = -ENOTTY; 6227bd1d409SAlexander Shishkin u64 options; 6237bd1d409SAlexander Shishkin 6247bd1d409SAlexander Shishkin switch (cmd) { 6257bd1d409SAlexander Shishkin case STP_POLICY_ID_SET: 6267bd1d409SAlexander Shishkin err = stm_char_policy_set_ioctl(stmf, (void __user *)arg); 6277bd1d409SAlexander Shishkin if (err) 6287bd1d409SAlexander Shishkin return err; 6297bd1d409SAlexander Shishkin 6307bd1d409SAlexander Shishkin return stm_char_policy_get_ioctl(stmf, (void __user *)arg); 6317bd1d409SAlexander Shishkin 6327bd1d409SAlexander Shishkin case STP_POLICY_ID_GET: 6337bd1d409SAlexander Shishkin return stm_char_policy_get_ioctl(stmf, (void __user *)arg); 6347bd1d409SAlexander Shishkin 6357bd1d409SAlexander Shishkin case STP_SET_OPTIONS: 6367bd1d409SAlexander Shishkin if (copy_from_user(&options, (u64 __user *)arg, sizeof(u64))) 6377bd1d409SAlexander Shishkin return -EFAULT; 6387bd1d409SAlexander Shishkin 6397bd1d409SAlexander Shishkin if (stm_data->set_options) 6407bd1d409SAlexander Shishkin err = stm_data->set_options(stm_data, 6417bd1d409SAlexander Shishkin stmf->output.master, 6427bd1d409SAlexander Shishkin stmf->output.channel, 6437bd1d409SAlexander Shishkin stmf->output.nr_chans, 6447bd1d409SAlexander Shishkin options); 6457bd1d409SAlexander Shishkin 6467bd1d409SAlexander Shishkin break; 6477bd1d409SAlexander Shishkin default: 6487bd1d409SAlexander Shishkin break; 6497bd1d409SAlexander Shishkin } 6507bd1d409SAlexander Shishkin 6517bd1d409SAlexander Shishkin return err; 6527bd1d409SAlexander Shishkin } 6537bd1d409SAlexander Shishkin 6547bd1d409SAlexander Shishkin #ifdef CONFIG_COMPAT 6557bd1d409SAlexander Shishkin static long 6567bd1d409SAlexander Shishkin stm_char_compat_ioctl(struct file *file, unsigned int cmd, unsigned long arg) 6577bd1d409SAlexander Shishkin { 6587bd1d409SAlexander Shishkin return stm_char_ioctl(file, cmd, (unsigned long)compat_ptr(arg)); 6597bd1d409SAlexander Shishkin } 6607bd1d409SAlexander Shishkin #else 6617bd1d409SAlexander Shishkin #define stm_char_compat_ioctl NULL 6627bd1d409SAlexander Shishkin #endif 6637bd1d409SAlexander Shishkin 6647bd1d409SAlexander Shishkin static const struct file_operations stm_fops = { 6657bd1d409SAlexander Shishkin .open = stm_char_open, 6667bd1d409SAlexander Shishkin .release = stm_char_release, 6677bd1d409SAlexander Shishkin .write = stm_char_write, 6687bd1d409SAlexander Shishkin .mmap = stm_char_mmap, 6697bd1d409SAlexander Shishkin .unlocked_ioctl = stm_char_ioctl, 6707bd1d409SAlexander Shishkin .compat_ioctl = stm_char_compat_ioctl, 6717bd1d409SAlexander Shishkin .llseek = no_llseek, 6727bd1d409SAlexander Shishkin }; 6737bd1d409SAlexander Shishkin 6747bd1d409SAlexander Shishkin static void stm_device_release(struct device *dev) 6757bd1d409SAlexander Shishkin { 6767bd1d409SAlexander Shishkin struct stm_device *stm = to_stm_device(dev); 6777bd1d409SAlexander Shishkin 678b5e2ced9SAlexander Shishkin vfree(stm); 6797bd1d409SAlexander Shishkin } 6807bd1d409SAlexander Shishkin 6817bd1d409SAlexander Shishkin int stm_register_device(struct device *parent, struct stm_data *stm_data, 6827bd1d409SAlexander Shishkin struct module *owner) 6837bd1d409SAlexander Shishkin { 6847bd1d409SAlexander Shishkin struct stm_device *stm; 6857bd1d409SAlexander Shishkin unsigned int nmasters; 6867bd1d409SAlexander Shishkin int err = -ENOMEM; 6877bd1d409SAlexander Shishkin 6887bd1d409SAlexander Shishkin if (!stm_core_up) 6897bd1d409SAlexander Shishkin return -EPROBE_DEFER; 6907bd1d409SAlexander Shishkin 6917bd1d409SAlexander Shishkin if (!stm_data->packet || !stm_data->sw_nchannels) 6927bd1d409SAlexander Shishkin return -EINVAL; 6937bd1d409SAlexander Shishkin 6947b3bb0e7SChunyan Zhang nmasters = stm_data->sw_end - stm_data->sw_start + 1; 695b5e2ced9SAlexander Shishkin stm = vzalloc(sizeof(*stm) + nmasters * sizeof(void *)); 6967bd1d409SAlexander Shishkin if (!stm) 6977bd1d409SAlexander Shishkin return -ENOMEM; 6987bd1d409SAlexander Shishkin 6997bd1d409SAlexander Shishkin stm->major = register_chrdev(0, stm_data->name, &stm_fops); 7007bd1d409SAlexander Shishkin if (stm->major < 0) 7017bd1d409SAlexander Shishkin goto err_free; 7027bd1d409SAlexander Shishkin 7037bd1d409SAlexander Shishkin device_initialize(&stm->dev); 7047bd1d409SAlexander Shishkin stm->dev.devt = MKDEV(stm->major, 0); 7057bd1d409SAlexander Shishkin stm->dev.class = &stm_class; 7067bd1d409SAlexander Shishkin stm->dev.parent = parent; 7077bd1d409SAlexander Shishkin stm->dev.release = stm_device_release; 7087bd1d409SAlexander Shishkin 709389b6699SAlexander Shishkin mutex_init(&stm->link_mutex); 710389b6699SAlexander Shishkin spin_lock_init(&stm->link_lock); 711389b6699SAlexander Shishkin INIT_LIST_HEAD(&stm->link_list); 712389b6699SAlexander Shishkin 713389b6699SAlexander Shishkin /* initialize the object before it is accessible via sysfs */ 714389b6699SAlexander Shishkin spin_lock_init(&stm->mc_lock); 715389b6699SAlexander Shishkin mutex_init(&stm->policy_mutex); 716389b6699SAlexander Shishkin stm->sw_nmasters = nmasters; 717389b6699SAlexander Shishkin stm->owner = owner; 718389b6699SAlexander Shishkin stm->data = stm_data; 719389b6699SAlexander Shishkin stm_data->stm = stm; 720389b6699SAlexander Shishkin 7217bd1d409SAlexander Shishkin err = kobject_set_name(&stm->dev.kobj, "%s", stm_data->name); 7227bd1d409SAlexander Shishkin if (err) 7237bd1d409SAlexander Shishkin goto err_device; 7247bd1d409SAlexander Shishkin 7257bd1d409SAlexander Shishkin err = device_add(&stm->dev); 7267bd1d409SAlexander Shishkin if (err) 7277bd1d409SAlexander Shishkin goto err_device; 7287bd1d409SAlexander Shishkin 7298e0469a4SAlexander Shishkin /* 7308e0469a4SAlexander Shishkin * Use delayed autosuspend to avoid bouncing back and forth 7318e0469a4SAlexander Shishkin * on recurring character device writes, with the initial 7328e0469a4SAlexander Shishkin * delay time of 2 seconds. 7338e0469a4SAlexander Shishkin */ 7348e0469a4SAlexander Shishkin pm_runtime_no_callbacks(&stm->dev); 7358e0469a4SAlexander Shishkin pm_runtime_use_autosuspend(&stm->dev); 7368e0469a4SAlexander Shishkin pm_runtime_set_autosuspend_delay(&stm->dev, 2000); 7378e0469a4SAlexander Shishkin pm_runtime_set_suspended(&stm->dev); 7388e0469a4SAlexander Shishkin pm_runtime_enable(&stm->dev); 7398e0469a4SAlexander Shishkin 7407bd1d409SAlexander Shishkin return 0; 7417bd1d409SAlexander Shishkin 7427bd1d409SAlexander Shishkin err_device: 743cbe4a61dSAlexander Shishkin unregister_chrdev(stm->major, stm_data->name); 744cbe4a61dSAlexander Shishkin 745f7c81c71SAlexander Shishkin /* matches device_initialize() above */ 7467bd1d409SAlexander Shishkin put_device(&stm->dev); 7477bd1d409SAlexander Shishkin err_free: 748b5e2ced9SAlexander Shishkin vfree(stm); 7497bd1d409SAlexander Shishkin 7507bd1d409SAlexander Shishkin return err; 7517bd1d409SAlexander Shishkin } 7527bd1d409SAlexander Shishkin EXPORT_SYMBOL_GPL(stm_register_device); 7537bd1d409SAlexander Shishkin 754b4ca34aaSAlexander Shishkin static int __stm_source_link_drop(struct stm_source_device *src, 7557bd1d409SAlexander Shishkin struct stm_device *stm); 7567bd1d409SAlexander Shishkin 7577bd1d409SAlexander Shishkin void stm_unregister_device(struct stm_data *stm_data) 7587bd1d409SAlexander Shishkin { 7597bd1d409SAlexander Shishkin struct stm_device *stm = stm_data->stm; 7607bd1d409SAlexander Shishkin struct stm_source_device *src, *iter; 761b4ca34aaSAlexander Shishkin int i, ret; 7627bd1d409SAlexander Shishkin 7638e0469a4SAlexander Shishkin pm_runtime_dont_use_autosuspend(&stm->dev); 7648e0469a4SAlexander Shishkin pm_runtime_disable(&stm->dev); 7658e0469a4SAlexander Shishkin 766c74f7e82SAlexander Shishkin mutex_lock(&stm->link_mutex); 7677bd1d409SAlexander Shishkin list_for_each_entry_safe(src, iter, &stm->link_list, link_entry) { 768b4ca34aaSAlexander Shishkin ret = __stm_source_link_drop(src, stm); 769b4ca34aaSAlexander Shishkin /* 770b4ca34aaSAlexander Shishkin * src <-> stm link must not change under the same 771b4ca34aaSAlexander Shishkin * stm::link_mutex, so complain loudly if it has; 772b4ca34aaSAlexander Shishkin * also in this situation ret!=0 means this src is 773b4ca34aaSAlexander Shishkin * not connected to this stm and it should be otherwise 774b4ca34aaSAlexander Shishkin * safe to proceed with the tear-down of stm. 775b4ca34aaSAlexander Shishkin */ 776b4ca34aaSAlexander Shishkin WARN_ON_ONCE(ret); 7777bd1d409SAlexander Shishkin } 778c74f7e82SAlexander Shishkin mutex_unlock(&stm->link_mutex); 7797bd1d409SAlexander Shishkin 7807bd1d409SAlexander Shishkin synchronize_srcu(&stm_source_srcu); 7817bd1d409SAlexander Shishkin 7827bd1d409SAlexander Shishkin unregister_chrdev(stm->major, stm_data->name); 7837bd1d409SAlexander Shishkin 7847bd1d409SAlexander Shishkin mutex_lock(&stm->policy_mutex); 7857bd1d409SAlexander Shishkin if (stm->policy) 7867bd1d409SAlexander Shishkin stp_policy_unbind(stm->policy); 7877bd1d409SAlexander Shishkin mutex_unlock(&stm->policy_mutex); 7887bd1d409SAlexander Shishkin 78973a3ed19SChunyan Zhang for (i = stm->data->sw_start; i <= stm->data->sw_end; i++) 7907bd1d409SAlexander Shishkin stp_master_free(stm, i); 7917bd1d409SAlexander Shishkin 7927bd1d409SAlexander Shishkin device_unregister(&stm->dev); 7937bd1d409SAlexander Shishkin stm_data->stm = NULL; 7947bd1d409SAlexander Shishkin } 7957bd1d409SAlexander Shishkin EXPORT_SYMBOL_GPL(stm_unregister_device); 7967bd1d409SAlexander Shishkin 797c74f7e82SAlexander Shishkin /* 798c74f7e82SAlexander Shishkin * stm::link_list access serialization uses a spinlock and a mutex; holding 799c74f7e82SAlexander Shishkin * either of them guarantees that the list is stable; modification requires 800c74f7e82SAlexander Shishkin * holding both of them. 801c74f7e82SAlexander Shishkin * 802c74f7e82SAlexander Shishkin * Lock ordering is as follows: 803c74f7e82SAlexander Shishkin * stm::link_mutex 804c74f7e82SAlexander Shishkin * stm::link_lock 805c74f7e82SAlexander Shishkin * src::link_lock 806c74f7e82SAlexander Shishkin */ 807c74f7e82SAlexander Shishkin 8087bd1d409SAlexander Shishkin /** 8097bd1d409SAlexander Shishkin * stm_source_link_add() - connect an stm_source device to an stm device 8107bd1d409SAlexander Shishkin * @src: stm_source device 8117bd1d409SAlexander Shishkin * @stm: stm device 8127bd1d409SAlexander Shishkin * 8137bd1d409SAlexander Shishkin * This function establishes a link from stm_source to an stm device so that 8147bd1d409SAlexander Shishkin * the former can send out trace data to the latter. 8157bd1d409SAlexander Shishkin * 8167bd1d409SAlexander Shishkin * Return: 0 on success, -errno otherwise. 8177bd1d409SAlexander Shishkin */ 8187bd1d409SAlexander Shishkin static int stm_source_link_add(struct stm_source_device *src, 8197bd1d409SAlexander Shishkin struct stm_device *stm) 8207bd1d409SAlexander Shishkin { 8217bd1d409SAlexander Shishkin char *id; 8227bd1d409SAlexander Shishkin int err; 8237bd1d409SAlexander Shishkin 824c74f7e82SAlexander Shishkin mutex_lock(&stm->link_mutex); 8257bd1d409SAlexander Shishkin spin_lock(&stm->link_lock); 8267bd1d409SAlexander Shishkin spin_lock(&src->link_lock); 8277bd1d409SAlexander Shishkin 8287bd1d409SAlexander Shishkin /* src->link is dereferenced under stm_source_srcu but not the list */ 8297bd1d409SAlexander Shishkin rcu_assign_pointer(src->link, stm); 8307bd1d409SAlexander Shishkin list_add_tail(&src->link_entry, &stm->link_list); 8317bd1d409SAlexander Shishkin 8327bd1d409SAlexander Shishkin spin_unlock(&src->link_lock); 8337bd1d409SAlexander Shishkin spin_unlock(&stm->link_lock); 834c74f7e82SAlexander Shishkin mutex_unlock(&stm->link_mutex); 8357bd1d409SAlexander Shishkin 8367bd1d409SAlexander Shishkin id = kstrdup(src->data->name, GFP_KERNEL); 8377bd1d409SAlexander Shishkin if (id) { 8387bd1d409SAlexander Shishkin src->policy_node = 8397bd1d409SAlexander Shishkin stp_policy_node_lookup(stm, id); 8407bd1d409SAlexander Shishkin 8417bd1d409SAlexander Shishkin kfree(id); 8427bd1d409SAlexander Shishkin } 8437bd1d409SAlexander Shishkin 8447bd1d409SAlexander Shishkin err = stm_output_assign(stm, src->data->nr_chans, 8457bd1d409SAlexander Shishkin src->policy_node, &src->output); 8467bd1d409SAlexander Shishkin 8477bd1d409SAlexander Shishkin if (src->policy_node) 8487bd1d409SAlexander Shishkin stp_policy_node_put(src->policy_node); 8497bd1d409SAlexander Shishkin 8507bd1d409SAlexander Shishkin if (err) 8517bd1d409SAlexander Shishkin goto fail_detach; 8527bd1d409SAlexander Shishkin 8537bd1d409SAlexander Shishkin /* this is to notify the STM device that a new link has been made */ 8547bd1d409SAlexander Shishkin if (stm->data->link) 8557bd1d409SAlexander Shishkin err = stm->data->link(stm->data, src->output.master, 8567bd1d409SAlexander Shishkin src->output.channel); 8577bd1d409SAlexander Shishkin 8587bd1d409SAlexander Shishkin if (err) 8597bd1d409SAlexander Shishkin goto fail_free_output; 8607bd1d409SAlexander Shishkin 8617bd1d409SAlexander Shishkin /* this is to let the source carry out all necessary preparations */ 8627bd1d409SAlexander Shishkin if (src->data->link) 8637bd1d409SAlexander Shishkin src->data->link(src->data); 8647bd1d409SAlexander Shishkin 8657bd1d409SAlexander Shishkin return 0; 8667bd1d409SAlexander Shishkin 8677bd1d409SAlexander Shishkin fail_free_output: 8687bd1d409SAlexander Shishkin stm_output_free(stm, &src->output); 8697bd1d409SAlexander Shishkin 8707bd1d409SAlexander Shishkin fail_detach: 871c74f7e82SAlexander Shishkin mutex_lock(&stm->link_mutex); 8727bd1d409SAlexander Shishkin spin_lock(&stm->link_lock); 8737bd1d409SAlexander Shishkin spin_lock(&src->link_lock); 8747bd1d409SAlexander Shishkin 8757bd1d409SAlexander Shishkin rcu_assign_pointer(src->link, NULL); 8767bd1d409SAlexander Shishkin list_del_init(&src->link_entry); 8777bd1d409SAlexander Shishkin 8787bd1d409SAlexander Shishkin spin_unlock(&src->link_lock); 8797bd1d409SAlexander Shishkin spin_unlock(&stm->link_lock); 880c74f7e82SAlexander Shishkin mutex_unlock(&stm->link_mutex); 8817bd1d409SAlexander Shishkin 8827bd1d409SAlexander Shishkin return err; 8837bd1d409SAlexander Shishkin } 8847bd1d409SAlexander Shishkin 8857bd1d409SAlexander Shishkin /** 8867bd1d409SAlexander Shishkin * __stm_source_link_drop() - detach stm_source from an stm device 8877bd1d409SAlexander Shishkin * @src: stm_source device 8887bd1d409SAlexander Shishkin * @stm: stm device 8897bd1d409SAlexander Shishkin * 8907bd1d409SAlexander Shishkin * If @stm is @src::link, disconnect them from one another and put the 8917bd1d409SAlexander Shishkin * reference on the @stm device. 8927bd1d409SAlexander Shishkin * 893c74f7e82SAlexander Shishkin * Caller must hold stm::link_mutex. 8947bd1d409SAlexander Shishkin */ 895b4ca34aaSAlexander Shishkin static int __stm_source_link_drop(struct stm_source_device *src, 8967bd1d409SAlexander Shishkin struct stm_device *stm) 8977bd1d409SAlexander Shishkin { 8980df771deSAlexander Shishkin struct stm_device *link; 899b4ca34aaSAlexander Shishkin int ret = 0; 9000df771deSAlexander Shishkin 901c74f7e82SAlexander Shishkin lockdep_assert_held(&stm->link_mutex); 902c74f7e82SAlexander Shishkin 903c74f7e82SAlexander Shishkin /* for stm::link_list modification, we hold both mutex and spinlock */ 904c74f7e82SAlexander Shishkin spin_lock(&stm->link_lock); 9057bd1d409SAlexander Shishkin spin_lock(&src->link_lock); 9060df771deSAlexander Shishkin link = srcu_dereference_check(src->link, &stm_source_srcu, 1); 907b4ca34aaSAlexander Shishkin 908b4ca34aaSAlexander Shishkin /* 909b4ca34aaSAlexander Shishkin * The linked device may have changed since we last looked, because 910b4ca34aaSAlexander Shishkin * we weren't holding the src::link_lock back then; if this is the 911b4ca34aaSAlexander Shishkin * case, tell the caller to retry. 912b4ca34aaSAlexander Shishkin */ 913b4ca34aaSAlexander Shishkin if (link != stm) { 914b4ca34aaSAlexander Shishkin ret = -EAGAIN; 9151810f2c4SAlexander Shishkin goto unlock; 916b4ca34aaSAlexander Shishkin } 9177bd1d409SAlexander Shishkin 9180df771deSAlexander Shishkin stm_output_free(link, &src->output); 9197bd1d409SAlexander Shishkin list_del_init(&src->link_entry); 9208e0469a4SAlexander Shishkin pm_runtime_mark_last_busy(&link->dev); 9218e0469a4SAlexander Shishkin pm_runtime_put_autosuspend(&link->dev); 9227bd1d409SAlexander Shishkin /* matches stm_find_device() from stm_source_link_store() */ 9230df771deSAlexander Shishkin stm_put_device(link); 9247bd1d409SAlexander Shishkin rcu_assign_pointer(src->link, NULL); 9257bd1d409SAlexander Shishkin 9261810f2c4SAlexander Shishkin unlock: 9277bd1d409SAlexander Shishkin spin_unlock(&src->link_lock); 928c74f7e82SAlexander Shishkin spin_unlock(&stm->link_lock); 929b4ca34aaSAlexander Shishkin 930cc842407SAlexander Shishkin /* 931cc842407SAlexander Shishkin * Call the unlink callbacks for both source and stm, when we know 932cc842407SAlexander Shishkin * that we have actually performed the unlinking. 933cc842407SAlexander Shishkin */ 934cc842407SAlexander Shishkin if (!ret) { 935cc842407SAlexander Shishkin if (src->data->unlink) 936b4ca34aaSAlexander Shishkin src->data->unlink(src->data); 937b4ca34aaSAlexander Shishkin 938cc842407SAlexander Shishkin if (stm->data->unlink) 939cc842407SAlexander Shishkin stm->data->unlink(stm->data, src->output.master, 940cc842407SAlexander Shishkin src->output.channel); 941cc842407SAlexander Shishkin } 942cc842407SAlexander Shishkin 943b4ca34aaSAlexander Shishkin return ret; 9447bd1d409SAlexander Shishkin } 9457bd1d409SAlexander Shishkin 9467bd1d409SAlexander Shishkin /** 9477bd1d409SAlexander Shishkin * stm_source_link_drop() - detach stm_source from its stm device 9487bd1d409SAlexander Shishkin * @src: stm_source device 9497bd1d409SAlexander Shishkin * 9507bd1d409SAlexander Shishkin * Unlinking means disconnecting from source's STM device; after this 9517bd1d409SAlexander Shishkin * writes will be unsuccessful until it is linked to a new STM device. 9527bd1d409SAlexander Shishkin * 9537bd1d409SAlexander Shishkin * This will happen on "stm_source_link" sysfs attribute write to undo 9547bd1d409SAlexander Shishkin * the existing link (if any), or on linked STM device's de-registration. 9557bd1d409SAlexander Shishkin */ 9567bd1d409SAlexander Shishkin static void stm_source_link_drop(struct stm_source_device *src) 9577bd1d409SAlexander Shishkin { 9587bd1d409SAlexander Shishkin struct stm_device *stm; 959b4ca34aaSAlexander Shishkin int idx, ret; 9607bd1d409SAlexander Shishkin 961b4ca34aaSAlexander Shishkin retry: 9627bd1d409SAlexander Shishkin idx = srcu_read_lock(&stm_source_srcu); 963b4ca34aaSAlexander Shishkin /* 964b4ca34aaSAlexander Shishkin * The stm device will be valid for the duration of this 965b4ca34aaSAlexander Shishkin * read section, but the link may change before we grab 966b4ca34aaSAlexander Shishkin * the src::link_lock in __stm_source_link_drop(). 967b4ca34aaSAlexander Shishkin */ 9687bd1d409SAlexander Shishkin stm = srcu_dereference(src->link, &stm_source_srcu); 9697bd1d409SAlexander Shishkin 970b4ca34aaSAlexander Shishkin ret = 0; 9717bd1d409SAlexander Shishkin if (stm) { 972c74f7e82SAlexander Shishkin mutex_lock(&stm->link_mutex); 973b4ca34aaSAlexander Shishkin ret = __stm_source_link_drop(src, stm); 974c74f7e82SAlexander Shishkin mutex_unlock(&stm->link_mutex); 9757bd1d409SAlexander Shishkin } 9767bd1d409SAlexander Shishkin 9777bd1d409SAlexander Shishkin srcu_read_unlock(&stm_source_srcu, idx); 978b4ca34aaSAlexander Shishkin 979b4ca34aaSAlexander Shishkin /* if it did change, retry */ 980b4ca34aaSAlexander Shishkin if (ret == -EAGAIN) 981b4ca34aaSAlexander Shishkin goto retry; 9827bd1d409SAlexander Shishkin } 9837bd1d409SAlexander Shishkin 9847bd1d409SAlexander Shishkin static ssize_t stm_source_link_show(struct device *dev, 9857bd1d409SAlexander Shishkin struct device_attribute *attr, 9867bd1d409SAlexander Shishkin char *buf) 9877bd1d409SAlexander Shishkin { 9887bd1d409SAlexander Shishkin struct stm_source_device *src = to_stm_source_device(dev); 9897bd1d409SAlexander Shishkin struct stm_device *stm; 9907bd1d409SAlexander Shishkin int idx, ret; 9917bd1d409SAlexander Shishkin 9927bd1d409SAlexander Shishkin idx = srcu_read_lock(&stm_source_srcu); 9937bd1d409SAlexander Shishkin stm = srcu_dereference(src->link, &stm_source_srcu); 9947bd1d409SAlexander Shishkin ret = sprintf(buf, "%s\n", 9957bd1d409SAlexander Shishkin stm ? dev_name(&stm->dev) : "<none>"); 9967bd1d409SAlexander Shishkin srcu_read_unlock(&stm_source_srcu, idx); 9977bd1d409SAlexander Shishkin 9987bd1d409SAlexander Shishkin return ret; 9997bd1d409SAlexander Shishkin } 10007bd1d409SAlexander Shishkin 10017bd1d409SAlexander Shishkin static ssize_t stm_source_link_store(struct device *dev, 10027bd1d409SAlexander Shishkin struct device_attribute *attr, 10037bd1d409SAlexander Shishkin const char *buf, size_t count) 10047bd1d409SAlexander Shishkin { 10057bd1d409SAlexander Shishkin struct stm_source_device *src = to_stm_source_device(dev); 10067bd1d409SAlexander Shishkin struct stm_device *link; 10077bd1d409SAlexander Shishkin int err; 10087bd1d409SAlexander Shishkin 10097bd1d409SAlexander Shishkin stm_source_link_drop(src); 10107bd1d409SAlexander Shishkin 10117bd1d409SAlexander Shishkin link = stm_find_device(buf); 10127bd1d409SAlexander Shishkin if (!link) 10137bd1d409SAlexander Shishkin return -EINVAL; 10147bd1d409SAlexander Shishkin 10158e0469a4SAlexander Shishkin pm_runtime_get(&link->dev); 10168e0469a4SAlexander Shishkin 10177bd1d409SAlexander Shishkin err = stm_source_link_add(src, link); 1018f7c81c71SAlexander Shishkin if (err) { 10198e0469a4SAlexander Shishkin pm_runtime_put_autosuspend(&link->dev); 1020f7c81c71SAlexander Shishkin /* matches the stm_find_device() above */ 10217bd1d409SAlexander Shishkin stm_put_device(link); 1022f7c81c71SAlexander Shishkin } 10237bd1d409SAlexander Shishkin 10247bd1d409SAlexander Shishkin return err ? : count; 10257bd1d409SAlexander Shishkin } 10267bd1d409SAlexander Shishkin 10277bd1d409SAlexander Shishkin static DEVICE_ATTR_RW(stm_source_link); 10287bd1d409SAlexander Shishkin 10297bd1d409SAlexander Shishkin static struct attribute *stm_source_attrs[] = { 10307bd1d409SAlexander Shishkin &dev_attr_stm_source_link.attr, 10317bd1d409SAlexander Shishkin NULL, 10327bd1d409SAlexander Shishkin }; 10337bd1d409SAlexander Shishkin 10347bd1d409SAlexander Shishkin ATTRIBUTE_GROUPS(stm_source); 10357bd1d409SAlexander Shishkin 10367bd1d409SAlexander Shishkin static struct class stm_source_class = { 10377bd1d409SAlexander Shishkin .name = "stm_source", 10387bd1d409SAlexander Shishkin .dev_groups = stm_source_groups, 10397bd1d409SAlexander Shishkin }; 10407bd1d409SAlexander Shishkin 10417bd1d409SAlexander Shishkin static void stm_source_device_release(struct device *dev) 10427bd1d409SAlexander Shishkin { 10437bd1d409SAlexander Shishkin struct stm_source_device *src = to_stm_source_device(dev); 10447bd1d409SAlexander Shishkin 10457bd1d409SAlexander Shishkin kfree(src); 10467bd1d409SAlexander Shishkin } 10477bd1d409SAlexander Shishkin 10487bd1d409SAlexander Shishkin /** 10497bd1d409SAlexander Shishkin * stm_source_register_device() - register an stm_source device 10507bd1d409SAlexander Shishkin * @parent: parent device 10517bd1d409SAlexander Shishkin * @data: device description structure 10527bd1d409SAlexander Shishkin * 10537bd1d409SAlexander Shishkin * This will create a device of stm_source class that can write 10547bd1d409SAlexander Shishkin * data to an stm device once linked. 10557bd1d409SAlexander Shishkin * 10567bd1d409SAlexander Shishkin * Return: 0 on success, -errno otherwise. 10577bd1d409SAlexander Shishkin */ 10587bd1d409SAlexander Shishkin int stm_source_register_device(struct device *parent, 10597bd1d409SAlexander Shishkin struct stm_source_data *data) 10607bd1d409SAlexander Shishkin { 10617bd1d409SAlexander Shishkin struct stm_source_device *src; 10627bd1d409SAlexander Shishkin int err; 10637bd1d409SAlexander Shishkin 10647bd1d409SAlexander Shishkin if (!stm_core_up) 10657bd1d409SAlexander Shishkin return -EPROBE_DEFER; 10667bd1d409SAlexander Shishkin 10677bd1d409SAlexander Shishkin src = kzalloc(sizeof(*src), GFP_KERNEL); 10687bd1d409SAlexander Shishkin if (!src) 10697bd1d409SAlexander Shishkin return -ENOMEM; 10707bd1d409SAlexander Shishkin 10717bd1d409SAlexander Shishkin device_initialize(&src->dev); 10727bd1d409SAlexander Shishkin src->dev.class = &stm_source_class; 10737bd1d409SAlexander Shishkin src->dev.parent = parent; 10747bd1d409SAlexander Shishkin src->dev.release = stm_source_device_release; 10757bd1d409SAlexander Shishkin 10767bd1d409SAlexander Shishkin err = kobject_set_name(&src->dev.kobj, "%s", data->name); 10777bd1d409SAlexander Shishkin if (err) 10787bd1d409SAlexander Shishkin goto err; 10797bd1d409SAlexander Shishkin 10808e0469a4SAlexander Shishkin pm_runtime_no_callbacks(&src->dev); 10818e0469a4SAlexander Shishkin pm_runtime_forbid(&src->dev); 10828e0469a4SAlexander Shishkin 10837bd1d409SAlexander Shishkin err = device_add(&src->dev); 10847bd1d409SAlexander Shishkin if (err) 10857bd1d409SAlexander Shishkin goto err; 10867bd1d409SAlexander Shishkin 1087cde4ad83SAlexander Shishkin stm_output_init(&src->output); 10887bd1d409SAlexander Shishkin spin_lock_init(&src->link_lock); 10897bd1d409SAlexander Shishkin INIT_LIST_HEAD(&src->link_entry); 10907bd1d409SAlexander Shishkin src->data = data; 10917bd1d409SAlexander Shishkin data->src = src; 10927bd1d409SAlexander Shishkin 10937bd1d409SAlexander Shishkin return 0; 10947bd1d409SAlexander Shishkin 10957bd1d409SAlexander Shishkin err: 10967bd1d409SAlexander Shishkin put_device(&src->dev); 10977bd1d409SAlexander Shishkin kfree(src); 10987bd1d409SAlexander Shishkin 10997bd1d409SAlexander Shishkin return err; 11007bd1d409SAlexander Shishkin } 11017bd1d409SAlexander Shishkin EXPORT_SYMBOL_GPL(stm_source_register_device); 11027bd1d409SAlexander Shishkin 11037bd1d409SAlexander Shishkin /** 11047bd1d409SAlexander Shishkin * stm_source_unregister_device() - unregister an stm_source device 11057bd1d409SAlexander Shishkin * @data: device description that was used to register the device 11067bd1d409SAlexander Shishkin * 11077bd1d409SAlexander Shishkin * This will remove a previously created stm_source device from the system. 11087bd1d409SAlexander Shishkin */ 11097bd1d409SAlexander Shishkin void stm_source_unregister_device(struct stm_source_data *data) 11107bd1d409SAlexander Shishkin { 11117bd1d409SAlexander Shishkin struct stm_source_device *src = data->src; 11127bd1d409SAlexander Shishkin 11137bd1d409SAlexander Shishkin stm_source_link_drop(src); 11147bd1d409SAlexander Shishkin 1115fd085bb1SAlexander Shishkin device_unregister(&src->dev); 11167bd1d409SAlexander Shishkin } 11177bd1d409SAlexander Shishkin EXPORT_SYMBOL_GPL(stm_source_unregister_device); 11187bd1d409SAlexander Shishkin 11199dfed80dSChunyan Zhang int notrace stm_source_write(struct stm_source_data *data, 11209dfed80dSChunyan Zhang unsigned int chan, 11217bd1d409SAlexander Shishkin const char *buf, size_t count) 11227bd1d409SAlexander Shishkin { 11237bd1d409SAlexander Shishkin struct stm_source_device *src = data->src; 11247bd1d409SAlexander Shishkin struct stm_device *stm; 11257bd1d409SAlexander Shishkin int idx; 11267bd1d409SAlexander Shishkin 11277bd1d409SAlexander Shishkin if (!src->output.nr_chans) 11287bd1d409SAlexander Shishkin return -ENODEV; 11297bd1d409SAlexander Shishkin 11307bd1d409SAlexander Shishkin if (chan >= src->output.nr_chans) 11317bd1d409SAlexander Shishkin return -EINVAL; 11327bd1d409SAlexander Shishkin 11337bd1d409SAlexander Shishkin idx = srcu_read_lock(&stm_source_srcu); 11347bd1d409SAlexander Shishkin 11357bd1d409SAlexander Shishkin stm = srcu_dereference(src->link, &stm_source_srcu); 11367bd1d409SAlexander Shishkin if (stm) 1137f8560a9bSAlexander Shishkin count = stm_write(stm->data, src->output.master, 11387bd1d409SAlexander Shishkin src->output.channel + chan, 11397bd1d409SAlexander Shishkin buf, count); 11407bd1d409SAlexander Shishkin else 11417bd1d409SAlexander Shishkin count = -ENODEV; 11427bd1d409SAlexander Shishkin 11437bd1d409SAlexander Shishkin srcu_read_unlock(&stm_source_srcu, idx); 11447bd1d409SAlexander Shishkin 11457bd1d409SAlexander Shishkin return count; 11467bd1d409SAlexander Shishkin } 11477bd1d409SAlexander Shishkin EXPORT_SYMBOL_GPL(stm_source_write); 11487bd1d409SAlexander Shishkin 11497bd1d409SAlexander Shishkin static int __init stm_core_init(void) 11507bd1d409SAlexander Shishkin { 11517bd1d409SAlexander Shishkin int err; 11527bd1d409SAlexander Shishkin 11537bd1d409SAlexander Shishkin err = class_register(&stm_class); 11547bd1d409SAlexander Shishkin if (err) 11557bd1d409SAlexander Shishkin return err; 11567bd1d409SAlexander Shishkin 11577bd1d409SAlexander Shishkin err = class_register(&stm_source_class); 11587bd1d409SAlexander Shishkin if (err) 11597bd1d409SAlexander Shishkin goto err_stm; 11607bd1d409SAlexander Shishkin 11617bd1d409SAlexander Shishkin err = stp_configfs_init(); 11627bd1d409SAlexander Shishkin if (err) 11637bd1d409SAlexander Shishkin goto err_src; 11647bd1d409SAlexander Shishkin 11657bd1d409SAlexander Shishkin init_srcu_struct(&stm_source_srcu); 11667bd1d409SAlexander Shishkin 11677bd1d409SAlexander Shishkin stm_core_up++; 11687bd1d409SAlexander Shishkin 11697bd1d409SAlexander Shishkin return 0; 11707bd1d409SAlexander Shishkin 11717bd1d409SAlexander Shishkin err_src: 11727bd1d409SAlexander Shishkin class_unregister(&stm_source_class); 11737bd1d409SAlexander Shishkin err_stm: 11747bd1d409SAlexander Shishkin class_unregister(&stm_class); 11757bd1d409SAlexander Shishkin 11767bd1d409SAlexander Shishkin return err; 11777bd1d409SAlexander Shishkin } 11787bd1d409SAlexander Shishkin 11797bd1d409SAlexander Shishkin module_init(stm_core_init); 11807bd1d409SAlexander Shishkin 11817bd1d409SAlexander Shishkin static void __exit stm_core_exit(void) 11827bd1d409SAlexander Shishkin { 11837bd1d409SAlexander Shishkin cleanup_srcu_struct(&stm_source_srcu); 11847bd1d409SAlexander Shishkin class_unregister(&stm_source_class); 11857bd1d409SAlexander Shishkin class_unregister(&stm_class); 11867bd1d409SAlexander Shishkin stp_configfs_exit(); 11877bd1d409SAlexander Shishkin } 11887bd1d409SAlexander Shishkin 11897bd1d409SAlexander Shishkin module_exit(stm_core_exit); 11907bd1d409SAlexander Shishkin 11917bd1d409SAlexander Shishkin MODULE_LICENSE("GPL v2"); 11927bd1d409SAlexander Shishkin MODULE_DESCRIPTION("System Trace Module device class"); 11937bd1d409SAlexander Shishkin MODULE_AUTHOR("Alexander Shishkin <alexander.shishkin@linux.intel.com>"); 1194