fcfcf0deb8
HID standard allows sending a feature request to the device which is answered by an HID report. uhid implements this by sending a UHID_FEATURE event to user-space which then must answer with UHID_FEATURE_ANSWER. If it doesn't do this in a timely manner, the request is discarded silently. We serialize the feature requests, that is, there is always only a single active feature-request sent to user-space, other requests have to wait. HIDP and USB-HID do it the same way. Because we discard feature-requests silently, we must make sure to match a response to the corresponding request. We use sequence-IDs for this so user-space must copy the ID from the request into the answer. Feature-answers are ignored if they do not contain the same ID as the currently pending feature request. Internally, we must make sure that feature-requests are synchronized with UHID_DESTROY and close() events. We must not dead-lock when closing the HID device, either, so we have to use separate locks. Signed-off-by: David Herrmann <dh.herrmann@googlemail.com> Signed-off-by: Jiri Kosina <jkosina@suse.cz>
104 lines
2 KiB
C
104 lines
2 KiB
C
#ifndef __UHID_H_
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#define __UHID_H_
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/*
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* User-space I/O driver support for HID subsystem
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* Copyright (c) 2012 David Herrmann
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*/
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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 of the GNU General Public License as published by the Free
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* Software Foundation; either version 2 of the License, or (at your option)
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* any later version.
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*/
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/*
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* Public header for user-space communication. We try to keep every structure
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* aligned but to be safe we also use __attribute__((__packed__)). Therefore,
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* the communication should be ABI compatible even between architectures.
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*/
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#include <linux/input.h>
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#include <linux/types.h>
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enum uhid_event_type {
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UHID_CREATE,
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UHID_DESTROY,
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UHID_START,
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UHID_STOP,
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UHID_OPEN,
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UHID_CLOSE,
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UHID_OUTPUT,
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UHID_OUTPUT_EV,
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UHID_INPUT,
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UHID_FEATURE,
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UHID_FEATURE_ANSWER,
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};
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struct uhid_create_req {
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__u8 name[128];
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__u8 phys[64];
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__u8 uniq[64];
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__u8 __user *rd_data;
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__u16 rd_size;
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__u16 bus;
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__u32 vendor;
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__u32 product;
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__u32 version;
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__u32 country;
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} __attribute__((__packed__));
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#define UHID_DATA_MAX 4096
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enum uhid_report_type {
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UHID_FEATURE_REPORT,
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UHID_OUTPUT_REPORT,
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UHID_INPUT_REPORT,
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};
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struct uhid_input_req {
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__u8 data[UHID_DATA_MAX];
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__u16 size;
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} __attribute__((__packed__));
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struct uhid_output_req {
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__u8 data[UHID_DATA_MAX];
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__u16 size;
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__u8 rtype;
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} __attribute__((__packed__));
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struct uhid_output_ev_req {
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__u16 type;
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__u16 code;
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__s32 value;
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} __attribute__((__packed__));
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struct uhid_feature_req {
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__u32 id;
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__u8 rnum;
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__u8 rtype;
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} __attribute__((__packed__));
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struct uhid_feature_answer_req {
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__u32 id;
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__u16 err;
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__u16 size;
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__u8 data[UHID_DATA_MAX];
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};
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struct uhid_event {
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__u32 type;
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union {
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struct uhid_create_req create;
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struct uhid_input_req input;
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struct uhid_output_req output;
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struct uhid_output_ev_req output_ev;
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struct uhid_feature_req feature;
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struct uhid_feature_answer_req feature_answer;
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} u;
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} __attribute__((__packed__));
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#endif /* __UHID_H_ */
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