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1363 lines
30 KiB
1363 lines
30 KiB
// SPDX-License-Identifier: GPL-2.0 |
|
/* |
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* System Trace Module (STM) infrastructure |
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* Copyright (c) 2014, Intel Corporation. |
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* |
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* STM class implements generic infrastructure for System Trace Module devices |
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* as defined in MIPI STPv2 specification. |
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*/ |
|
|
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#include <linux/pm_runtime.h> |
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#include <linux/uaccess.h> |
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#include <linux/kernel.h> |
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#include <linux/module.h> |
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#include <linux/device.h> |
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#include <linux/compat.h> |
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#include <linux/kdev_t.h> |
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#include <linux/srcu.h> |
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#include <linux/slab.h> |
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#include <linux/stm.h> |
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#include <linux/fs.h> |
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#include <linux/mm.h> |
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#include <linux/vmalloc.h> |
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#include "stm.h" |
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|
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#include <uapi/linux/stm.h> |
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|
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static unsigned int stm_core_up; |
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|
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/* |
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* The SRCU here makes sure that STM device doesn't disappear from under a |
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* stm_source_write() caller, which may want to have as little overhead as |
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* possible. |
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*/ |
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static struct srcu_struct stm_source_srcu; |
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|
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static ssize_t masters_show(struct device *dev, |
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struct device_attribute *attr, |
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char *buf) |
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{ |
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struct stm_device *stm = to_stm_device(dev); |
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int ret; |
|
|
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ret = sprintf(buf, "%u %u\n", stm->data->sw_start, stm->data->sw_end); |
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|
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return ret; |
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} |
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|
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static DEVICE_ATTR_RO(masters); |
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|
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static ssize_t channels_show(struct device *dev, |
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struct device_attribute *attr, |
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char *buf) |
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{ |
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struct stm_device *stm = to_stm_device(dev); |
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int ret; |
|
|
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ret = sprintf(buf, "%u\n", stm->data->sw_nchannels); |
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|
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return ret; |
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} |
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|
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static DEVICE_ATTR_RO(channels); |
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|
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static ssize_t hw_override_show(struct device *dev, |
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struct device_attribute *attr, |
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char *buf) |
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{ |
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struct stm_device *stm = to_stm_device(dev); |
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int ret; |
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|
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ret = sprintf(buf, "%u\n", stm->data->hw_override); |
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|
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return ret; |
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} |
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|
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static DEVICE_ATTR_RO(hw_override); |
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|
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static struct attribute *stm_attrs[] = { |
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&dev_attr_masters.attr, |
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&dev_attr_channels.attr, |
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&dev_attr_hw_override.attr, |
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NULL, |
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}; |
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|
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ATTRIBUTE_GROUPS(stm); |
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|
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static struct class stm_class = { |
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.name = "stm", |
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.dev_groups = stm_groups, |
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}; |
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|
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/** |
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* stm_find_device() - find stm device by name |
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* @buf: character buffer containing the name |
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* |
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* This is called when either policy gets assigned to an stm device or an |
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* stm_source device gets linked to an stm device. |
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* |
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* This grabs device's reference (get_device()) and module reference, both |
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* of which the calling path needs to make sure to drop with stm_put_device(). |
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* |
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* Return: stm device pointer or null if lookup failed. |
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*/ |
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struct stm_device *stm_find_device(const char *buf) |
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{ |
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struct stm_device *stm; |
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struct device *dev; |
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|
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if (!stm_core_up) |
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return NULL; |
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|
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dev = class_find_device_by_name(&stm_class, buf); |
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if (!dev) |
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return NULL; |
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|
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stm = to_stm_device(dev); |
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if (!try_module_get(stm->owner)) { |
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/* matches class_find_device() above */ |
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put_device(dev); |
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return NULL; |
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} |
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|
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return stm; |
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} |
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|
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/** |
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* stm_put_device() - drop references on the stm device |
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* @stm: stm device, previously acquired by stm_find_device() |
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* |
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* This drops the module reference and device reference taken by |
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* stm_find_device() or stm_char_open(). |
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*/ |
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void stm_put_device(struct stm_device *stm) |
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{ |
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module_put(stm->owner); |
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put_device(&stm->dev); |
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} |
|
|
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/* |
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* Internally we only care about software-writable masters here, that is the |
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* ones in the range [stm_data->sw_start..stm_data..sw_end], however we need |
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* original master numbers to be visible externally, since they are the ones |
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* that will appear in the STP stream. Thus, the internal bookkeeping uses |
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* $master - stm_data->sw_start to reference master descriptors and such. |
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*/ |
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|
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#define __stm_master(_s, _m) \ |
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((_s)->masters[(_m) - (_s)->data->sw_start]) |
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|
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static inline struct stp_master * |
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stm_master(struct stm_device *stm, unsigned int idx) |
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{ |
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if (idx < stm->data->sw_start || idx > stm->data->sw_end) |
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return NULL; |
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|
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return __stm_master(stm, idx); |
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} |
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|
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static int stp_master_alloc(struct stm_device *stm, unsigned int idx) |
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{ |
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struct stp_master *master; |
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|
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master = kzalloc(struct_size(master, chan_map, |
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BITS_TO_LONGS(stm->data->sw_nchannels)), |
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GFP_ATOMIC); |
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if (!master) |
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return -ENOMEM; |
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|
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master->nr_free = stm->data->sw_nchannels; |
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__stm_master(stm, idx) = master; |
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|
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return 0; |
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} |
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|
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static void stp_master_free(struct stm_device *stm, unsigned int idx) |
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{ |
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struct stp_master *master = stm_master(stm, idx); |
|
|
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if (!master) |
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return; |
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|
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__stm_master(stm, idx) = NULL; |
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kfree(master); |
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} |
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|
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static void stm_output_claim(struct stm_device *stm, struct stm_output *output) |
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{ |
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struct stp_master *master = stm_master(stm, output->master); |
|
|
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lockdep_assert_held(&stm->mc_lock); |
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lockdep_assert_held(&output->lock); |
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|
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if (WARN_ON_ONCE(master->nr_free < output->nr_chans)) |
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return; |
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|
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bitmap_allocate_region(&master->chan_map[0], output->channel, |
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ilog2(output->nr_chans)); |
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|
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master->nr_free -= output->nr_chans; |
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} |
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|
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static void |
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stm_output_disclaim(struct stm_device *stm, struct stm_output *output) |
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{ |
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struct stp_master *master = stm_master(stm, output->master); |
|
|
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lockdep_assert_held(&stm->mc_lock); |
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lockdep_assert_held(&output->lock); |
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|
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bitmap_release_region(&master->chan_map[0], output->channel, |
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ilog2(output->nr_chans)); |
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|
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master->nr_free += output->nr_chans; |
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output->nr_chans = 0; |
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} |
|
|
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/* |
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* This is like bitmap_find_free_region(), except it can ignore @start bits |
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* at the beginning. |
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*/ |
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static int find_free_channels(unsigned long *bitmap, unsigned int start, |
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unsigned int end, unsigned int width) |
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{ |
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unsigned int pos; |
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int i; |
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|
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for (pos = start; pos < end + 1; pos = ALIGN(pos, width)) { |
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pos = find_next_zero_bit(bitmap, end + 1, pos); |
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if (pos + width > end + 1) |
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break; |
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|
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if (pos & (width - 1)) |
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continue; |
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|
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for (i = 1; i < width && !test_bit(pos + i, bitmap); i++) |
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; |
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if (i == width) |
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return pos; |
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|
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/* step over [pos..pos+i) to continue search */ |
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pos += i; |
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} |
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|
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return -1; |
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} |
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|
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static int |
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stm_find_master_chan(struct stm_device *stm, unsigned int width, |
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unsigned int *mstart, unsigned int mend, |
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unsigned int *cstart, unsigned int cend) |
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{ |
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struct stp_master *master; |
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unsigned int midx; |
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int pos, err; |
|
|
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for (midx = *mstart; midx <= mend; midx++) { |
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if (!stm_master(stm, midx)) { |
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err = stp_master_alloc(stm, midx); |
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if (err) |
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return err; |
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} |
|
|
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master = stm_master(stm, midx); |
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|
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if (!master->nr_free) |
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continue; |
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|
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pos = find_free_channels(master->chan_map, *cstart, cend, |
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width); |
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if (pos < 0) |
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continue; |
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|
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*mstart = midx; |
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*cstart = pos; |
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return 0; |
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} |
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|
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return -ENOSPC; |
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} |
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|
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static int stm_output_assign(struct stm_device *stm, unsigned int width, |
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struct stp_policy_node *policy_node, |
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struct stm_output *output) |
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{ |
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unsigned int midx, cidx, mend, cend; |
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int ret = -EINVAL; |
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|
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if (width > stm->data->sw_nchannels) |
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return -EINVAL; |
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|
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/* We no longer accept policy_node==NULL here */ |
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if (WARN_ON_ONCE(!policy_node)) |
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return -EINVAL; |
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|
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/* |
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* Also, the caller holds reference to policy_node, so it won't |
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* disappear on us. |
|
*/ |
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stp_policy_node_get_ranges(policy_node, &midx, &mend, &cidx, &cend); |
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|
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spin_lock(&stm->mc_lock); |
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spin_lock(&output->lock); |
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/* output is already assigned -- shouldn't happen */ |
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if (WARN_ON_ONCE(output->nr_chans)) |
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goto unlock; |
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|
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ret = stm_find_master_chan(stm, width, &midx, mend, &cidx, cend); |
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if (ret < 0) |
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goto unlock; |
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|
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output->master = midx; |
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output->channel = cidx; |
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output->nr_chans = width; |
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if (stm->pdrv->output_open) { |
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void *priv = stp_policy_node_priv(policy_node); |
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|
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if (WARN_ON_ONCE(!priv)) |
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goto unlock; |
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|
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/* configfs subsys mutex is held by the caller */ |
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ret = stm->pdrv->output_open(priv, output); |
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if (ret) |
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goto unlock; |
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} |
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stm_output_claim(stm, output); |
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dev_dbg(&stm->dev, "assigned %u:%u (+%u)\n", midx, cidx, width); |
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|
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ret = 0; |
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unlock: |
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if (ret) |
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output->nr_chans = 0; |
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|
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spin_unlock(&output->lock); |
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spin_unlock(&stm->mc_lock); |
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|
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return ret; |
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} |
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|
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static void stm_output_free(struct stm_device *stm, struct stm_output *output) |
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{ |
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spin_lock(&stm->mc_lock); |
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spin_lock(&output->lock); |
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if (output->nr_chans) |
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stm_output_disclaim(stm, output); |
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if (stm->pdrv && stm->pdrv->output_close) |
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stm->pdrv->output_close(output); |
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spin_unlock(&output->lock); |
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spin_unlock(&stm->mc_lock); |
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} |
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|
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static void stm_output_init(struct stm_output *output) |
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{ |
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spin_lock_init(&output->lock); |
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} |
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|
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static int major_match(struct device *dev, const void *data) |
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{ |
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unsigned int major = *(unsigned int *)data; |
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|
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return MAJOR(dev->devt) == major; |
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} |
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|
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/* |
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* Framing protocol management |
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* Modules can implement STM protocol drivers and (un-)register them |
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* with the STM class framework. |
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*/ |
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static struct list_head stm_pdrv_head; |
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static struct mutex stm_pdrv_mutex; |
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|
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struct stm_pdrv_entry { |
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struct list_head entry; |
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const struct stm_protocol_driver *pdrv; |
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const struct config_item_type *node_type; |
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}; |
|
|
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static const struct stm_pdrv_entry * |
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__stm_lookup_protocol(const char *name) |
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{ |
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struct stm_pdrv_entry *pe; |
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|
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/* |
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* If no name is given (NULL or ""), fall back to "p_basic". |
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*/ |
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if (!name || !*name) |
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name = "p_basic"; |
|
|
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list_for_each_entry(pe, &stm_pdrv_head, entry) { |
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if (!strcmp(name, pe->pdrv->name)) |
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return pe; |
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} |
|
|
|
return NULL; |
|
} |
|
|
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int stm_register_protocol(const struct stm_protocol_driver *pdrv) |
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{ |
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struct stm_pdrv_entry *pe = NULL; |
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int ret = -ENOMEM; |
|
|
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mutex_lock(&stm_pdrv_mutex); |
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|
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if (__stm_lookup_protocol(pdrv->name)) { |
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ret = -EEXIST; |
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goto unlock; |
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} |
|
|
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pe = kzalloc(sizeof(*pe), GFP_KERNEL); |
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if (!pe) |
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goto unlock; |
|
|
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if (pdrv->policy_attr) { |
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pe->node_type = get_policy_node_type(pdrv->policy_attr); |
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if (!pe->node_type) |
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goto unlock; |
|
} |
|
|
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list_add_tail(&pe->entry, &stm_pdrv_head); |
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pe->pdrv = pdrv; |
|
|
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ret = 0; |
|
unlock: |
|
mutex_unlock(&stm_pdrv_mutex); |
|
|
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if (ret) |
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kfree(pe); |
|
|
|
return ret; |
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} |
|
EXPORT_SYMBOL_GPL(stm_register_protocol); |
|
|
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void stm_unregister_protocol(const struct stm_protocol_driver *pdrv) |
|
{ |
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struct stm_pdrv_entry *pe, *iter; |
|
|
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mutex_lock(&stm_pdrv_mutex); |
|
|
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list_for_each_entry_safe(pe, iter, &stm_pdrv_head, entry) { |
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if (pe->pdrv == pdrv) { |
|
list_del(&pe->entry); |
|
|
|
if (pe->node_type) { |
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kfree(pe->node_type->ct_attrs); |
|
kfree(pe->node_type); |
|
} |
|
kfree(pe); |
|
break; |
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} |
|
} |
|
|
|
mutex_unlock(&stm_pdrv_mutex); |
|
} |
|
EXPORT_SYMBOL_GPL(stm_unregister_protocol); |
|
|
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static bool stm_get_protocol(const struct stm_protocol_driver *pdrv) |
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{ |
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return try_module_get(pdrv->owner); |
|
} |
|
|
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void stm_put_protocol(const struct stm_protocol_driver *pdrv) |
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{ |
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module_put(pdrv->owner); |
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} |
|
|
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int stm_lookup_protocol(const char *name, |
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const struct stm_protocol_driver **pdrv, |
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const struct config_item_type **node_type) |
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{ |
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const struct stm_pdrv_entry *pe; |
|
|
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mutex_lock(&stm_pdrv_mutex); |
|
|
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pe = __stm_lookup_protocol(name); |
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if (pe && pe->pdrv && stm_get_protocol(pe->pdrv)) { |
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*pdrv = pe->pdrv; |
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*node_type = pe->node_type; |
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} |
|
|
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mutex_unlock(&stm_pdrv_mutex); |
|
|
|
return pe ? 0 : -ENOENT; |
|
} |
|
|
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static int stm_char_open(struct inode *inode, struct file *file) |
|
{ |
|
struct stm_file *stmf; |
|
struct device *dev; |
|
unsigned int major = imajor(inode); |
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int err = -ENOMEM; |
|
|
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dev = class_find_device(&stm_class, NULL, &major, major_match); |
|
if (!dev) |
|
return -ENODEV; |
|
|
|
stmf = kzalloc(sizeof(*stmf), GFP_KERNEL); |
|
if (!stmf) |
|
goto err_put_device; |
|
|
|
err = -ENODEV; |
|
stm_output_init(&stmf->output); |
|
stmf->stm = to_stm_device(dev); |
|
|
|
if (!try_module_get(stmf->stm->owner)) |
|
goto err_free; |
|
|
|
file->private_data = stmf; |
|
|
|
return nonseekable_open(inode, file); |
|
|
|
err_free: |
|
kfree(stmf); |
|
err_put_device: |
|
/* matches class_find_device() above */ |
|
put_device(dev); |
|
|
|
return err; |
|
} |
|
|
|
static int stm_char_release(struct inode *inode, struct file *file) |
|
{ |
|
struct stm_file *stmf = file->private_data; |
|
struct stm_device *stm = stmf->stm; |
|
|
|
if (stm->data->unlink) |
|
stm->data->unlink(stm->data, stmf->output.master, |
|
stmf->output.channel); |
|
|
|
stm_output_free(stm, &stmf->output); |
|
|
|
/* |
|
* matches the stm_char_open()'s |
|
* class_find_device() + try_module_get() |
|
*/ |
|
stm_put_device(stm); |
|
kfree(stmf); |
|
|
|
return 0; |
|
} |
|
|
|
static int |
|
stm_assign_first_policy(struct stm_device *stm, struct stm_output *output, |
|
char **ids, unsigned int width) |
|
{ |
|
struct stp_policy_node *pn; |
|
int err, n; |
|
|
|
/* |
|
* On success, stp_policy_node_lookup() will return holding the |
|
* configfs subsystem mutex, which is then released in |
|
* stp_policy_node_put(). This allows the pdrv->output_open() in |
|
* stm_output_assign() to serialize against the attribute accessors. |
|
*/ |
|
for (n = 0, pn = NULL; ids[n] && !pn; n++) |
|
pn = stp_policy_node_lookup(stm, ids[n]); |
|
|
|
if (!pn) |
|
return -EINVAL; |
|
|
|
err = stm_output_assign(stm, width, pn, output); |
|
|
|
stp_policy_node_put(pn); |
|
|
|
return err; |
|
} |
|
|
|
/** |
|
* stm_data_write() - send the given payload as data packets |
|
* @data: stm driver's data |
|
* @m: STP master |
|
* @c: STP channel |
|
* @ts_first: timestamp the first packet |
|
* @buf: data payload buffer |
|
* @count: data payload size |
|
*/ |
|
ssize_t notrace stm_data_write(struct stm_data *data, unsigned int m, |
|
unsigned int c, bool ts_first, const void *buf, |
|
size_t count) |
|
{ |
|
unsigned int flags = ts_first ? STP_PACKET_TIMESTAMPED : 0; |
|
ssize_t sz; |
|
size_t pos; |
|
|
|
for (pos = 0, sz = 0; pos < count; pos += sz) { |
|
sz = min_t(unsigned int, count - pos, 8); |
|
sz = data->packet(data, m, c, STP_PACKET_DATA, flags, sz, |
|
&((u8 *)buf)[pos]); |
|
if (sz <= 0) |
|
break; |
|
|
|
if (ts_first) { |
|
flags = 0; |
|
ts_first = false; |
|
} |
|
} |
|
|
|
return sz < 0 ? sz : pos; |
|
} |
|
EXPORT_SYMBOL_GPL(stm_data_write); |
|
|
|
static ssize_t notrace |
|
stm_write(struct stm_device *stm, struct stm_output *output, |
|
unsigned int chan, const char *buf, size_t count) |
|
{ |
|
int err; |
|
|
|
/* stm->pdrv is serialized against policy_mutex */ |
|
if (!stm->pdrv) |
|
return -ENODEV; |
|
|
|
err = stm->pdrv->write(stm->data, output, chan, buf, count); |
|
if (err < 0) |
|
return err; |
|
|
|
return err; |
|
} |
|
|
|
static ssize_t stm_char_write(struct file *file, const char __user *buf, |
|
size_t count, loff_t *ppos) |
|
{ |
|
struct stm_file *stmf = file->private_data; |
|
struct stm_device *stm = stmf->stm; |
|
char *kbuf; |
|
int err; |
|
|
|
if (count + 1 > PAGE_SIZE) |
|
count = PAGE_SIZE - 1; |
|
|
|
/* |
|
* If no m/c have been assigned to this writer up to this |
|
* point, try to use the task name and "default" policy entries. |
|
*/ |
|
if (!stmf->output.nr_chans) { |
|
char comm[sizeof(current->comm)]; |
|
char *ids[] = { comm, "default", NULL }; |
|
|
|
get_task_comm(comm, current); |
|
|
|
err = stm_assign_first_policy(stmf->stm, &stmf->output, ids, 1); |
|
/* |
|
* EBUSY means that somebody else just assigned this |
|
* output, which is just fine for write() |
|
*/ |
|
if (err) |
|
return err; |
|
} |
|
|
|
kbuf = kmalloc(count + 1, GFP_KERNEL); |
|
if (!kbuf) |
|
return -ENOMEM; |
|
|
|
err = copy_from_user(kbuf, buf, count); |
|
if (err) { |
|
kfree(kbuf); |
|
return -EFAULT; |
|
} |
|
|
|
pm_runtime_get_sync(&stm->dev); |
|
|
|
count = stm_write(stm, &stmf->output, 0, kbuf, count); |
|
|
|
pm_runtime_mark_last_busy(&stm->dev); |
|
pm_runtime_put_autosuspend(&stm->dev); |
|
kfree(kbuf); |
|
|
|
return count; |
|
} |
|
|
|
static void stm_mmap_open(struct vm_area_struct *vma) |
|
{ |
|
struct stm_file *stmf = vma->vm_file->private_data; |
|
struct stm_device *stm = stmf->stm; |
|
|
|
pm_runtime_get(&stm->dev); |
|
} |
|
|
|
static void stm_mmap_close(struct vm_area_struct *vma) |
|
{ |
|
struct stm_file *stmf = vma->vm_file->private_data; |
|
struct stm_device *stm = stmf->stm; |
|
|
|
pm_runtime_mark_last_busy(&stm->dev); |
|
pm_runtime_put_autosuspend(&stm->dev); |
|
} |
|
|
|
static const struct vm_operations_struct stm_mmap_vmops = { |
|
.open = stm_mmap_open, |
|
.close = stm_mmap_close, |
|
}; |
|
|
|
static int stm_char_mmap(struct file *file, struct vm_area_struct *vma) |
|
{ |
|
struct stm_file *stmf = file->private_data; |
|
struct stm_device *stm = stmf->stm; |
|
unsigned long size, phys; |
|
|
|
if (!stm->data->mmio_addr) |
|
return -EOPNOTSUPP; |
|
|
|
if (vma->vm_pgoff) |
|
return -EINVAL; |
|
|
|
size = vma->vm_end - vma->vm_start; |
|
|
|
if (stmf->output.nr_chans * stm->data->sw_mmiosz != size) |
|
return -EINVAL; |
|
|
|
phys = stm->data->mmio_addr(stm->data, stmf->output.master, |
|
stmf->output.channel, |
|
stmf->output.nr_chans); |
|
|
|
if (!phys) |
|
return -EINVAL; |
|
|
|
pm_runtime_get_sync(&stm->dev); |
|
|
|
vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot); |
|
vma->vm_flags |= VM_IO | VM_DONTEXPAND | VM_DONTDUMP; |
|
vma->vm_ops = &stm_mmap_vmops; |
|
vm_iomap_memory(vma, phys, size); |
|
|
|
return 0; |
|
} |
|
|
|
static int stm_char_policy_set_ioctl(struct stm_file *stmf, void __user *arg) |
|
{ |
|
struct stm_device *stm = stmf->stm; |
|
struct stp_policy_id *id; |
|
char *ids[] = { NULL, NULL }; |
|
int ret = -EINVAL, wlimit = 1; |
|
u32 size; |
|
|
|
if (stmf->output.nr_chans) |
|
return -EBUSY; |
|
|
|
if (copy_from_user(&size, arg, sizeof(size))) |
|
return -EFAULT; |
|
|
|
if (size < sizeof(*id) || size >= PATH_MAX + sizeof(*id)) |
|
return -EINVAL; |
|
|
|
/* |
|
* size + 1 to make sure the .id string at the bottom is terminated, |
|
* which is also why memdup_user() is not useful here |
|
*/ |
|
id = kzalloc(size + 1, GFP_KERNEL); |
|
if (!id) |
|
return -ENOMEM; |
|
|
|
if (copy_from_user(id, arg, size)) { |
|
ret = -EFAULT; |
|
goto err_free; |
|
} |
|
|
|
if (id->__reserved_0 || id->__reserved_1) |
|
goto err_free; |
|
|
|
if (stm->data->sw_mmiosz) |
|
wlimit = PAGE_SIZE / stm->data->sw_mmiosz; |
|
|
|
if (id->width < 1 || id->width > wlimit) |
|
goto err_free; |
|
|
|
ids[0] = id->id; |
|
ret = stm_assign_first_policy(stmf->stm, &stmf->output, ids, |
|
id->width); |
|
if (ret) |
|
goto err_free; |
|
|
|
if (stm->data->link) |
|
ret = stm->data->link(stm->data, stmf->output.master, |
|
stmf->output.channel); |
|
|
|
if (ret) |
|
stm_output_free(stmf->stm, &stmf->output); |
|
|
|
err_free: |
|
kfree(id); |
|
|
|
return ret; |
|
} |
|
|
|
static int stm_char_policy_get_ioctl(struct stm_file *stmf, void __user *arg) |
|
{ |
|
struct stp_policy_id id = { |
|
.size = sizeof(id), |
|
.master = stmf->output.master, |
|
.channel = stmf->output.channel, |
|
.width = stmf->output.nr_chans, |
|
.__reserved_0 = 0, |
|
.__reserved_1 = 0, |
|
}; |
|
|
|
return copy_to_user(arg, &id, id.size) ? -EFAULT : 0; |
|
} |
|
|
|
static long |
|
stm_char_ioctl(struct file *file, unsigned int cmd, unsigned long arg) |
|
{ |
|
struct stm_file *stmf = file->private_data; |
|
struct stm_data *stm_data = stmf->stm->data; |
|
int err = -ENOTTY; |
|
u64 options; |
|
|
|
switch (cmd) { |
|
case STP_POLICY_ID_SET: |
|
err = stm_char_policy_set_ioctl(stmf, (void __user *)arg); |
|
if (err) |
|
return err; |
|
|
|
return stm_char_policy_get_ioctl(stmf, (void __user *)arg); |
|
|
|
case STP_POLICY_ID_GET: |
|
return stm_char_policy_get_ioctl(stmf, (void __user *)arg); |
|
|
|
case STP_SET_OPTIONS: |
|
if (copy_from_user(&options, (u64 __user *)arg, sizeof(u64))) |
|
return -EFAULT; |
|
|
|
if (stm_data->set_options) |
|
err = stm_data->set_options(stm_data, |
|
stmf->output.master, |
|
stmf->output.channel, |
|
stmf->output.nr_chans, |
|
options); |
|
|
|
break; |
|
default: |
|
break; |
|
} |
|
|
|
return err; |
|
} |
|
|
|
static const struct file_operations stm_fops = { |
|
.open = stm_char_open, |
|
.release = stm_char_release, |
|
.write = stm_char_write, |
|
.mmap = stm_char_mmap, |
|
.unlocked_ioctl = stm_char_ioctl, |
|
.compat_ioctl = compat_ptr_ioctl, |
|
.llseek = no_llseek, |
|
}; |
|
|
|
static void stm_device_release(struct device *dev) |
|
{ |
|
struct stm_device *stm = to_stm_device(dev); |
|
|
|
vfree(stm); |
|
} |
|
|
|
int stm_register_device(struct device *parent, struct stm_data *stm_data, |
|
struct module *owner) |
|
{ |
|
struct stm_device *stm; |
|
unsigned int nmasters; |
|
int err = -ENOMEM; |
|
|
|
if (!stm_core_up) |
|
return -EPROBE_DEFER; |
|
|
|
if (!stm_data->packet || !stm_data->sw_nchannels) |
|
return -EINVAL; |
|
|
|
nmasters = stm_data->sw_end - stm_data->sw_start + 1; |
|
stm = vzalloc(sizeof(*stm) + nmasters * sizeof(void *)); |
|
if (!stm) |
|
return -ENOMEM; |
|
|
|
stm->major = register_chrdev(0, stm_data->name, &stm_fops); |
|
if (stm->major < 0) |
|
goto err_free; |
|
|
|
device_initialize(&stm->dev); |
|
stm->dev.devt = MKDEV(stm->major, 0); |
|
stm->dev.class = &stm_class; |
|
stm->dev.parent = parent; |
|
stm->dev.release = stm_device_release; |
|
|
|
mutex_init(&stm->link_mutex); |
|
spin_lock_init(&stm->link_lock); |
|
INIT_LIST_HEAD(&stm->link_list); |
|
|
|
/* initialize the object before it is accessible via sysfs */ |
|
spin_lock_init(&stm->mc_lock); |
|
mutex_init(&stm->policy_mutex); |
|
stm->sw_nmasters = nmasters; |
|
stm->owner = owner; |
|
stm->data = stm_data; |
|
stm_data->stm = stm; |
|
|
|
err = kobject_set_name(&stm->dev.kobj, "%s", stm_data->name); |
|
if (err) |
|
goto err_device; |
|
|
|
err = device_add(&stm->dev); |
|
if (err) |
|
goto err_device; |
|
|
|
/* |
|
* Use delayed autosuspend to avoid bouncing back and forth |
|
* on recurring character device writes, with the initial |
|
* delay time of 2 seconds. |
|
*/ |
|
pm_runtime_no_callbacks(&stm->dev); |
|
pm_runtime_use_autosuspend(&stm->dev); |
|
pm_runtime_set_autosuspend_delay(&stm->dev, 2000); |
|
pm_runtime_set_suspended(&stm->dev); |
|
pm_runtime_enable(&stm->dev); |
|
|
|
return 0; |
|
|
|
err_device: |
|
unregister_chrdev(stm->major, stm_data->name); |
|
|
|
/* matches device_initialize() above */ |
|
put_device(&stm->dev); |
|
err_free: |
|
vfree(stm); |
|
|
|
return err; |
|
} |
|
EXPORT_SYMBOL_GPL(stm_register_device); |
|
|
|
static int __stm_source_link_drop(struct stm_source_device *src, |
|
struct stm_device *stm); |
|
|
|
void stm_unregister_device(struct stm_data *stm_data) |
|
{ |
|
struct stm_device *stm = stm_data->stm; |
|
struct stm_source_device *src, *iter; |
|
int i, ret; |
|
|
|
pm_runtime_dont_use_autosuspend(&stm->dev); |
|
pm_runtime_disable(&stm->dev); |
|
|
|
mutex_lock(&stm->link_mutex); |
|
list_for_each_entry_safe(src, iter, &stm->link_list, link_entry) { |
|
ret = __stm_source_link_drop(src, stm); |
|
/* |
|
* src <-> stm link must not change under the same |
|
* stm::link_mutex, so complain loudly if it has; |
|
* also in this situation ret!=0 means this src is |
|
* not connected to this stm and it should be otherwise |
|
* safe to proceed with the tear-down of stm. |
|
*/ |
|
WARN_ON_ONCE(ret); |
|
} |
|
mutex_unlock(&stm->link_mutex); |
|
|
|
synchronize_srcu(&stm_source_srcu); |
|
|
|
unregister_chrdev(stm->major, stm_data->name); |
|
|
|
mutex_lock(&stm->policy_mutex); |
|
if (stm->policy) |
|
stp_policy_unbind(stm->policy); |
|
mutex_unlock(&stm->policy_mutex); |
|
|
|
for (i = stm->data->sw_start; i <= stm->data->sw_end; i++) |
|
stp_master_free(stm, i); |
|
|
|
device_unregister(&stm->dev); |
|
stm_data->stm = NULL; |
|
} |
|
EXPORT_SYMBOL_GPL(stm_unregister_device); |
|
|
|
/* |
|
* stm::link_list access serialization uses a spinlock and a mutex; holding |
|
* either of them guarantees that the list is stable; modification requires |
|
* holding both of them. |
|
* |
|
* Lock ordering is as follows: |
|
* stm::link_mutex |
|
* stm::link_lock |
|
* src::link_lock |
|
*/ |
|
|
|
/** |
|
* stm_source_link_add() - connect an stm_source device to an stm device |
|
* @src: stm_source device |
|
* @stm: stm device |
|
* |
|
* This function establishes a link from stm_source to an stm device so that |
|
* the former can send out trace data to the latter. |
|
* |
|
* Return: 0 on success, -errno otherwise. |
|
*/ |
|
static int stm_source_link_add(struct stm_source_device *src, |
|
struct stm_device *stm) |
|
{ |
|
char *ids[] = { NULL, "default", NULL }; |
|
int err = -ENOMEM; |
|
|
|
mutex_lock(&stm->link_mutex); |
|
spin_lock(&stm->link_lock); |
|
spin_lock(&src->link_lock); |
|
|
|
/* src->link is dereferenced under stm_source_srcu but not the list */ |
|
rcu_assign_pointer(src->link, stm); |
|
list_add_tail(&src->link_entry, &stm->link_list); |
|
|
|
spin_unlock(&src->link_lock); |
|
spin_unlock(&stm->link_lock); |
|
mutex_unlock(&stm->link_mutex); |
|
|
|
ids[0] = kstrdup(src->data->name, GFP_KERNEL); |
|
if (!ids[0]) |
|
goto fail_detach; |
|
|
|
err = stm_assign_first_policy(stm, &src->output, ids, |
|
src->data->nr_chans); |
|
kfree(ids[0]); |
|
|
|
if (err) |
|
goto fail_detach; |
|
|
|
/* this is to notify the STM device that a new link has been made */ |
|
if (stm->data->link) |
|
err = stm->data->link(stm->data, src->output.master, |
|
src->output.channel); |
|
|
|
if (err) |
|
goto fail_free_output; |
|
|
|
/* this is to let the source carry out all necessary preparations */ |
|
if (src->data->link) |
|
src->data->link(src->data); |
|
|
|
return 0; |
|
|
|
fail_free_output: |
|
stm_output_free(stm, &src->output); |
|
|
|
fail_detach: |
|
mutex_lock(&stm->link_mutex); |
|
spin_lock(&stm->link_lock); |
|
spin_lock(&src->link_lock); |
|
|
|
rcu_assign_pointer(src->link, NULL); |
|
list_del_init(&src->link_entry); |
|
|
|
spin_unlock(&src->link_lock); |
|
spin_unlock(&stm->link_lock); |
|
mutex_unlock(&stm->link_mutex); |
|
|
|
return err; |
|
} |
|
|
|
/** |
|
* __stm_source_link_drop() - detach stm_source from an stm device |
|
* @src: stm_source device |
|
* @stm: stm device |
|
* |
|
* If @stm is @src::link, disconnect them from one another and put the |
|
* reference on the @stm device. |
|
* |
|
* Caller must hold stm::link_mutex. |
|
*/ |
|
static int __stm_source_link_drop(struct stm_source_device *src, |
|
struct stm_device *stm) |
|
{ |
|
struct stm_device *link; |
|
int ret = 0; |
|
|
|
lockdep_assert_held(&stm->link_mutex); |
|
|
|
/* for stm::link_list modification, we hold both mutex and spinlock */ |
|
spin_lock(&stm->link_lock); |
|
spin_lock(&src->link_lock); |
|
link = srcu_dereference_check(src->link, &stm_source_srcu, 1); |
|
|
|
/* |
|
* The linked device may have changed since we last looked, because |
|
* we weren't holding the src::link_lock back then; if this is the |
|
* case, tell the caller to retry. |
|
*/ |
|
if (link != stm) { |
|
ret = -EAGAIN; |
|
goto unlock; |
|
} |
|
|
|
stm_output_free(link, &src->output); |
|
list_del_init(&src->link_entry); |
|
pm_runtime_mark_last_busy(&link->dev); |
|
pm_runtime_put_autosuspend(&link->dev); |
|
/* matches stm_find_device() from stm_source_link_store() */ |
|
stm_put_device(link); |
|
rcu_assign_pointer(src->link, NULL); |
|
|
|
unlock: |
|
spin_unlock(&src->link_lock); |
|
spin_unlock(&stm->link_lock); |
|
|
|
/* |
|
* Call the unlink callbacks for both source and stm, when we know |
|
* that we have actually performed the unlinking. |
|
*/ |
|
if (!ret) { |
|
if (src->data->unlink) |
|
src->data->unlink(src->data); |
|
|
|
if (stm->data->unlink) |
|
stm->data->unlink(stm->data, src->output.master, |
|
src->output.channel); |
|
} |
|
|
|
return ret; |
|
} |
|
|
|
/** |
|
* stm_source_link_drop() - detach stm_source from its stm device |
|
* @src: stm_source device |
|
* |
|
* Unlinking means disconnecting from source's STM device; after this |
|
* writes will be unsuccessful until it is linked to a new STM device. |
|
* |
|
* This will happen on "stm_source_link" sysfs attribute write to undo |
|
* the existing link (if any), or on linked STM device's de-registration. |
|
*/ |
|
static void stm_source_link_drop(struct stm_source_device *src) |
|
{ |
|
struct stm_device *stm; |
|
int idx, ret; |
|
|
|
retry: |
|
idx = srcu_read_lock(&stm_source_srcu); |
|
/* |
|
* The stm device will be valid for the duration of this |
|
* read section, but the link may change before we grab |
|
* the src::link_lock in __stm_source_link_drop(). |
|
*/ |
|
stm = srcu_dereference(src->link, &stm_source_srcu); |
|
|
|
ret = 0; |
|
if (stm) { |
|
mutex_lock(&stm->link_mutex); |
|
ret = __stm_source_link_drop(src, stm); |
|
mutex_unlock(&stm->link_mutex); |
|
} |
|
|
|
srcu_read_unlock(&stm_source_srcu, idx); |
|
|
|
/* if it did change, retry */ |
|
if (ret == -EAGAIN) |
|
goto retry; |
|
} |
|
|
|
static ssize_t stm_source_link_show(struct device *dev, |
|
struct device_attribute *attr, |
|
char *buf) |
|
{ |
|
struct stm_source_device *src = to_stm_source_device(dev); |
|
struct stm_device *stm; |
|
int idx, ret; |
|
|
|
idx = srcu_read_lock(&stm_source_srcu); |
|
stm = srcu_dereference(src->link, &stm_source_srcu); |
|
ret = sprintf(buf, "%s\n", |
|
stm ? dev_name(&stm->dev) : "<none>"); |
|
srcu_read_unlock(&stm_source_srcu, idx); |
|
|
|
return ret; |
|
} |
|
|
|
static ssize_t stm_source_link_store(struct device *dev, |
|
struct device_attribute *attr, |
|
const char *buf, size_t count) |
|
{ |
|
struct stm_source_device *src = to_stm_source_device(dev); |
|
struct stm_device *link; |
|
int err; |
|
|
|
stm_source_link_drop(src); |
|
|
|
link = stm_find_device(buf); |
|
if (!link) |
|
return -EINVAL; |
|
|
|
pm_runtime_get(&link->dev); |
|
|
|
err = stm_source_link_add(src, link); |
|
if (err) { |
|
pm_runtime_put_autosuspend(&link->dev); |
|
/* matches the stm_find_device() above */ |
|
stm_put_device(link); |
|
} |
|
|
|
return err ? : count; |
|
} |
|
|
|
static DEVICE_ATTR_RW(stm_source_link); |
|
|
|
static struct attribute *stm_source_attrs[] = { |
|
&dev_attr_stm_source_link.attr, |
|
NULL, |
|
}; |
|
|
|
ATTRIBUTE_GROUPS(stm_source); |
|
|
|
static struct class stm_source_class = { |
|
.name = "stm_source", |
|
.dev_groups = stm_source_groups, |
|
}; |
|
|
|
static void stm_source_device_release(struct device *dev) |
|
{ |
|
struct stm_source_device *src = to_stm_source_device(dev); |
|
|
|
kfree(src); |
|
} |
|
|
|
/** |
|
* stm_source_register_device() - register an stm_source device |
|
* @parent: parent device |
|
* @data: device description structure |
|
* |
|
* This will create a device of stm_source class that can write |
|
* data to an stm device once linked. |
|
* |
|
* Return: 0 on success, -errno otherwise. |
|
*/ |
|
int stm_source_register_device(struct device *parent, |
|
struct stm_source_data *data) |
|
{ |
|
struct stm_source_device *src; |
|
int err; |
|
|
|
if (!stm_core_up) |
|
return -EPROBE_DEFER; |
|
|
|
src = kzalloc(sizeof(*src), GFP_KERNEL); |
|
if (!src) |
|
return -ENOMEM; |
|
|
|
device_initialize(&src->dev); |
|
src->dev.class = &stm_source_class; |
|
src->dev.parent = parent; |
|
src->dev.release = stm_source_device_release; |
|
|
|
err = kobject_set_name(&src->dev.kobj, "%s", data->name); |
|
if (err) |
|
goto err; |
|
|
|
pm_runtime_no_callbacks(&src->dev); |
|
pm_runtime_forbid(&src->dev); |
|
|
|
err = device_add(&src->dev); |
|
if (err) |
|
goto err; |
|
|
|
stm_output_init(&src->output); |
|
spin_lock_init(&src->link_lock); |
|
INIT_LIST_HEAD(&src->link_entry); |
|
src->data = data; |
|
data->src = src; |
|
|
|
return 0; |
|
|
|
err: |
|
put_device(&src->dev); |
|
|
|
return err; |
|
} |
|
EXPORT_SYMBOL_GPL(stm_source_register_device); |
|
|
|
/** |
|
* stm_source_unregister_device() - unregister an stm_source device |
|
* @data: device description that was used to register the device |
|
* |
|
* This will remove a previously created stm_source device from the system. |
|
*/ |
|
void stm_source_unregister_device(struct stm_source_data *data) |
|
{ |
|
struct stm_source_device *src = data->src; |
|
|
|
stm_source_link_drop(src); |
|
|
|
device_unregister(&src->dev); |
|
} |
|
EXPORT_SYMBOL_GPL(stm_source_unregister_device); |
|
|
|
int notrace stm_source_write(struct stm_source_data *data, |
|
unsigned int chan, |
|
const char *buf, size_t count) |
|
{ |
|
struct stm_source_device *src = data->src; |
|
struct stm_device *stm; |
|
int idx; |
|
|
|
if (!src->output.nr_chans) |
|
return -ENODEV; |
|
|
|
if (chan >= src->output.nr_chans) |
|
return -EINVAL; |
|
|
|
idx = srcu_read_lock(&stm_source_srcu); |
|
|
|
stm = srcu_dereference(src->link, &stm_source_srcu); |
|
if (stm) |
|
count = stm_write(stm, &src->output, chan, buf, count); |
|
else |
|
count = -ENODEV; |
|
|
|
srcu_read_unlock(&stm_source_srcu, idx); |
|
|
|
return count; |
|
} |
|
EXPORT_SYMBOL_GPL(stm_source_write); |
|
|
|
static int __init stm_core_init(void) |
|
{ |
|
int err; |
|
|
|
err = class_register(&stm_class); |
|
if (err) |
|
return err; |
|
|
|
err = class_register(&stm_source_class); |
|
if (err) |
|
goto err_stm; |
|
|
|
err = stp_configfs_init(); |
|
if (err) |
|
goto err_src; |
|
|
|
init_srcu_struct(&stm_source_srcu); |
|
INIT_LIST_HEAD(&stm_pdrv_head); |
|
mutex_init(&stm_pdrv_mutex); |
|
|
|
/* |
|
* So as to not confuse existing users with a requirement |
|
* to load yet another module, do it here. |
|
*/ |
|
if (IS_ENABLED(CONFIG_STM_PROTO_BASIC)) |
|
(void)request_module_nowait("stm_p_basic"); |
|
stm_core_up++; |
|
|
|
return 0; |
|
|
|
err_src: |
|
class_unregister(&stm_source_class); |
|
err_stm: |
|
class_unregister(&stm_class); |
|
|
|
return err; |
|
} |
|
|
|
module_init(stm_core_init); |
|
|
|
static void __exit stm_core_exit(void) |
|
{ |
|
cleanup_srcu_struct(&stm_source_srcu); |
|
class_unregister(&stm_source_class); |
|
class_unregister(&stm_class); |
|
stp_configfs_exit(); |
|
} |
|
|
|
module_exit(stm_core_exit); |
|
|
|
MODULE_LICENSE("GPL v2"); |
|
MODULE_DESCRIPTION("System Trace Module device class"); |
|
MODULE_AUTHOR("Alexander Shishkin <[email protected]>");
|
|
|