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cde4ad8368
It is possible to concurrently assign the same output (a character device writer or an stm_source device) to different stm devices, which sets off a strategically placed warning in stm_output_assign(). To avoid this, use a spinlock to serialize (un)assignments between outputs and stm devices. Signed-off-by: Alexander Shishkin <alexander.shishkin@linux.intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
89 lines
2.3 KiB
C
89 lines
2.3 KiB
C
/*
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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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* This program is free software; you can redistribute it and/or modify it
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* under the terms and conditions of the GNU General Public License,
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* version 2, as published by the Free Software Foundation.
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*
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* This program is distributed in the hope it will be useful, but WITHOUT
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* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
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* more details.
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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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#ifndef _STM_STM_H_
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#define _STM_STM_H_
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struct stp_policy;
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struct stp_policy_node;
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struct stp_policy_node *
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stp_policy_node_lookup(struct stm_device *stm, char *s);
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void stp_policy_node_put(struct stp_policy_node *policy_node);
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void stp_policy_unbind(struct stp_policy *policy);
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void stp_policy_node_get_ranges(struct stp_policy_node *policy_node,
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unsigned int *mstart, unsigned int *mend,
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unsigned int *cstart, unsigned int *cend);
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int stp_configfs_init(void);
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void stp_configfs_exit(void);
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struct stp_master {
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unsigned int nr_free;
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unsigned long chan_map[0];
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};
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struct stm_device {
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struct device dev;
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struct module *owner;
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struct stp_policy *policy;
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struct mutex policy_mutex;
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int major;
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unsigned int sw_nmasters;
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struct stm_data *data;
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struct mutex link_mutex;
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spinlock_t link_lock;
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struct list_head link_list;
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/* master allocation */
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spinlock_t mc_lock;
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struct stp_master *masters[0];
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};
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#define to_stm_device(_d) \
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container_of((_d), struct stm_device, dev)
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struct stm_output {
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spinlock_t lock;
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unsigned int master;
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unsigned int channel;
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unsigned int nr_chans;
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};
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struct stm_file {
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struct stm_device *stm;
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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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struct stm_device *stm_find_device(const char *name);
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void stm_put_device(struct stm_device *stm);
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struct stm_source_device {
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struct device dev;
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struct stm_source_data *data;
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spinlock_t link_lock;
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struct stm_device __rcu *link;
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struct list_head link_entry;
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/* one output per stm_source device */
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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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#define to_stm_source_device(_d) \
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container_of((_d), struct stm_source_device, dev)
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#endif /* _STM_STM_H_ */
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