1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * System Trace Module (STM) infrastructure apis 4 * Copyright (C) 2014 Intel Corporation. 5 */ 6 7 #ifndef _STM_H_ 8 #define _STM_H_ 9 10 #include <linux/device.h> 11 12 /** 13 * enum stp_packet_type - STP packets that an STM driver sends 14 */ 15 enum stp_packet_type { 16 STP_PACKET_DATA = 0, 17 STP_PACKET_FLAG, 18 STP_PACKET_USER, 19 STP_PACKET_MERR, 20 STP_PACKET_GERR, 21 STP_PACKET_TRIG, 22 STP_PACKET_XSYNC, 23 }; 24 25 /** 26 * enum stp_packet_flags - STP packet modifiers 27 */ 28 enum stp_packet_flags { 29 STP_PACKET_MARKED = 0x1, 30 STP_PACKET_TIMESTAMPED = 0x2, 31 }; 32 33 struct stp_policy; 34 35 struct stm_device; 36 37 /** 38 * struct stm_data - STM device description and callbacks 39 * @name: device name 40 * @stm: internal structure, only used by stm class code 41 * @sw_start: first STP master available to software 42 * @sw_end: last STP master available to software 43 * @sw_nchannels: number of STP channels per master 44 * @sw_mmiosz: size of one channel's IO space, for mmap, optional 45 * @hw_override: masters in the STP stream will not match the ones 46 * assigned by software, but are up to the STM hardware 47 * @packet: callback that sends an STP packet 48 * @mmio_addr: mmap callback, optional 49 * @link: called when a new stm_source gets linked to us, optional 50 * @unlink: likewise for unlinking, again optional 51 * @set_options: set device-specific options on a channel 52 * 53 * Fill out this structure before calling stm_register_device() to create 54 * an STM device and stm_unregister_device() to destroy it. It will also be 55 * passed back to @packet(), @mmio_addr(), @link(), @unlink() and @set_options() 56 * callbacks. 57 * 58 * Normally, an STM device will have a range of masters available to software 59 * and the rest being statically assigned to various hardware trace sources. 60 * The former is defined by the range [@sw_start..@sw_end] of the device 61 * description. That is, the lowest master that can be allocated to software 62 * writers is @sw_start and data from this writer will appear is @sw_start 63 * master in the STP stream. 64 * 65 * The @packet callback should adhere to the following rules: 66 * 1) it must return the number of bytes it consumed from the payload; 67 * 2) therefore, if it sent a packet that does not have payload (like FLAG), 68 * it must return zero; 69 * 3) if it does not support the requested packet type/flag combination, 70 * it must return -ENOTSUPP. 71 * 72 * The @unlink callback is called when there are no more active writers so 73 * that the master/channel can be quiesced. 74 */ 75 struct stm_data { 76 const char *name; 77 struct stm_device *stm; 78 unsigned int sw_start; 79 unsigned int sw_end; 80 unsigned int sw_nchannels; 81 unsigned int sw_mmiosz; 82 unsigned int hw_override; 83 ssize_t (*packet)(struct stm_data *, unsigned int, 84 unsigned int, unsigned int, 85 unsigned int, unsigned int, 86 const unsigned char *); 87 phys_addr_t (*mmio_addr)(struct stm_data *, unsigned int, 88 unsigned int, unsigned int); 89 int (*link)(struct stm_data *, unsigned int, 90 unsigned int); 91 void (*unlink)(struct stm_data *, unsigned int, 92 unsigned int); 93 long (*set_options)(struct stm_data *, unsigned int, 94 unsigned int, unsigned int, 95 unsigned long); 96 }; 97 98 int stm_register_device(struct device *parent, struct stm_data *stm_data, 99 struct module *owner); 100 void stm_unregister_device(struct stm_data *stm_data); 101 102 struct stm_source_device; 103 104 /** 105 * struct stm_source_data - STM source device description and callbacks 106 * @name: device name, will be used for policy lookup 107 * @src: internal structure, only used by stm class code 108 * @nr_chans: number of channels to allocate 109 * @link: called when this source gets linked to an STM device 110 * @unlink: called when this source is about to get unlinked from its STM 111 * 112 * Fill in this structure before calling stm_source_register_device() to 113 * register a source device. Also pass it to unregister and write calls. 114 */ 115 struct stm_source_data { 116 const char *name; 117 struct stm_source_device *src; 118 unsigned int percpu; 119 unsigned int nr_chans; 120 int (*link)(struct stm_source_data *data); 121 void (*unlink)(struct stm_source_data *data); 122 }; 123 124 int stm_source_register_device(struct device *parent, 125 struct stm_source_data *data); 126 void stm_source_unregister_device(struct stm_source_data *data); 127 128 int notrace stm_source_write(struct stm_source_data *data, unsigned int chan, 129 const char *buf, size_t count); 130 131 #endif /* _STM_H_ */ 132