| 1 | /* The industrial I/O core - generic ring buffer interfaces. |
| 2 | * |
| 3 | * Copyright (c) 2008 Jonathan Cameron |
| 4 | * |
| 5 | * This program is free software; you can redistribute it and/or modify it |
| 6 | * under the terms of the GNU General Public License version 2 as published by |
| 7 | * the Free Software Foundation. |
| 8 | */ |
| 9 | |
| 10 | #ifndef _IIO_RING_GENERIC_H_ |
| 11 | #define _IIO_RING_GENERIC_H_ |
| 12 | #include "iio.h" |
| 13 | |
| 14 | struct iio_handler; |
| 15 | struct iio_ring_buffer; |
| 16 | struct iio_dev; |
| 17 | |
| 18 | /** |
| 19 | * iio_push_ring_event() - ring buffer specific push to event chrdev |
| 20 | * @ring_buf: ring buffer that is the event source |
| 21 | * @event_code: event indentification code |
| 22 | * @timestamp: time of event |
| 23 | **/ |
| 24 | int iio_push_ring_event(struct iio_ring_buffer *ring_buf, |
| 25 | int event_code, |
| 26 | s64 timestamp); |
| 27 | /** |
| 28 | * iio_push_or_escallate_ring_event() - escalate or add as appropriate |
| 29 | * @ring_buf: ring buffer that is the event source |
| 30 | * @event_code: event indentification code |
| 31 | * @timestamp: time of event |
| 32 | * |
| 33 | * Typical usecase is to escalate a 50% ring full to 75% full if noone has yet |
| 34 | * read the first event. Clearly the 50% full is no longer of interest in |
| 35 | * typical use case. |
| 36 | **/ |
| 37 | int iio_push_or_escallate_ring_event(struct iio_ring_buffer *ring_buf, |
| 38 | int event_code, |
| 39 | s64 timestamp); |
| 40 | |
| 41 | /** |
| 42 | * struct iio_ring_access_funcs - access functions for ring buffers. |
| 43 | * @mark_in_use: reference counting, typically to prevent module removal |
| 44 | * @unmark_in_use: reduce reference count when no longer using ring buffer |
| 45 | * @store_to: actually store stuff to the ring buffer |
| 46 | * @read_last: get the last element stored |
| 47 | * @rip_lots: try to get a specified number of elements (must exist) |
| 48 | * @mark_param_change: notify ring that some relevant parameter has changed |
| 49 | * Often this means the underlying storage may need to |
| 50 | * change. |
| 51 | * @request_update: if a parameter change has been marked, update underlying |
| 52 | * storage. |
| 53 | * @get_bpd: get current bytes per datum |
| 54 | * @set_bpd: set number of bytes per datum |
| 55 | * @get_length: get number of datums in ring |
| 56 | * @set_length: set number of datums in ring |
| 57 | * @is_enabled: query if ring is currently being used |
| 58 | * @enable: enable the ring |
| 59 | * |
| 60 | * The purpose of this structure is to make the ring buffer element |
| 61 | * modular as event for a given driver, different usecases may require |
| 62 | * different ring designs (space efficiency vs speed for example). |
| 63 | * |
| 64 | * It is worth noting that a given ring implementation may only support a small |
| 65 | * proportion of these functions. The core code 'should' cope fine with any of |
| 66 | * them not existing. |
| 67 | **/ |
| 68 | struct iio_ring_access_funcs { |
| 69 | void (*mark_in_use)(struct iio_ring_buffer *ring); |
| 70 | void (*unmark_in_use)(struct iio_ring_buffer *ring); |
| 71 | |
| 72 | int (*store_to)(struct iio_ring_buffer *ring, u8 *data, s64 timestamp); |
| 73 | int (*read_last)(struct iio_ring_buffer *ring, u8 *data); |
| 74 | int (*rip_lots)(struct iio_ring_buffer *ring, |
| 75 | size_t count, |
| 76 | u8 **data, |
| 77 | int *dead_offset); |
| 78 | |
| 79 | int (*mark_param_change)(struct iio_ring_buffer *ring); |
| 80 | int (*request_update)(struct iio_ring_buffer *ring); |
| 81 | |
| 82 | int (*get_bpd)(struct iio_ring_buffer *ring); |
| 83 | int (*set_bpd)(struct iio_ring_buffer *ring, size_t bpd); |
| 84 | int (*get_length)(struct iio_ring_buffer *ring); |
| 85 | int (*set_length)(struct iio_ring_buffer *ring, int length); |
| 86 | |
| 87 | int (*is_enabled)(struct iio_ring_buffer *ring); |
| 88 | int (*enable)(struct iio_ring_buffer *ring); |
| 89 | }; |
| 90 | |
| 91 | /** |
| 92 | * struct iio_ring_buffer - general ring buffer structure |
| 93 | * @dev: ring buffer device struct |
| 94 | * @access_dev: system device struct for the chrdev |
| 95 | * @indio_dev: industrial I/O device structure |
| 96 | * @owner: module that owns the ring buffer (for ref counting) |
| 97 | * @id: unique id number |
| 98 | * @access_id: device id number |
| 99 | * @length: [DEVICE] number of datums in ring |
| 100 | * @bpd: [DEVICE] size of individual datum including timestamp |
| 101 | * @loopcount: [INTERN] number of times the ring has looped |
| 102 | * @access_handler: [INTERN] chrdev access handling |
| 103 | * @ev_int: [INTERN] chrdev interface for the event chrdev |
| 104 | * @shared_ev_pointer: [INTERN] the shared event pointer to allow escalation of |
| 105 | * events |
| 106 | * @access: [DRIVER] ring access functions associated with the |
| 107 | * implementation. |
| 108 | * @preenable: [DRIVER] function to run prior to marking ring enabled |
| 109 | * @postenable: [DRIVER] function to run after marking ring enabled |
| 110 | * @predisable: [DRIVER] function to run prior to marking ring disabled |
| 111 | * @postdisable: [DRIVER] function to run after marking ring disabled |
| 112 | **/ |
| 113 | struct iio_ring_buffer { |
| 114 | struct device dev; |
| 115 | struct device access_dev; |
| 116 | struct iio_dev *indio_dev; |
| 117 | struct module *owner; |
| 118 | int id; |
| 119 | int access_id; |
| 120 | int length; |
| 121 | int bpd; |
| 122 | int loopcount; |
| 123 | struct iio_handler access_handler; |
| 124 | struct iio_event_interface ev_int; |
| 125 | struct iio_shared_ev_pointer shared_ev_pointer; |
| 126 | struct iio_ring_access_funcs access; |
| 127 | int (*preenable)(struct iio_dev *); |
| 128 | int (*postenable)(struct iio_dev *); |
| 129 | int (*predisable)(struct iio_dev *); |
| 130 | int (*postdisable)(struct iio_dev *); |
| 131 | |
| 132 | }; |
| 133 | void iio_ring_buffer_init(struct iio_ring_buffer *ring, |
| 134 | struct iio_dev *dev_info); |
| 135 | |
| 136 | /** |
| 137 | * __iio_update_ring_buffer() - update common elements of ring buffers |
| 138 | * @ring: ring buffer that is the event source |
| 139 | * @bytes_per_datum: size of individual datum including timestamp |
| 140 | * @length: number of datums in ring |
| 141 | **/ |
| 142 | static inline void __iio_update_ring_buffer(struct iio_ring_buffer *ring, |
| 143 | int bytes_per_datum, int length) |
| 144 | { |
| 145 | ring->bpd = bytes_per_datum; |
| 146 | ring->length = length; |
| 147 | ring->loopcount = 0; |
| 148 | } |
| 149 | |
| 150 | /** |
| 151 | * struct iio_scan_el - an individual element of a scan |
| 152 | * @dev_attr: control attribute (if directly controllable) |
| 153 | * @number: unique identifier of element (used for bit mask) |
| 154 | * @bit_count: number of bits in scan element |
| 155 | * @label: useful data for the scan el (often reg address) |
| 156 | * @set_state: for some devices datardy signals are generated |
| 157 | * for any enabled lines. This allows unwanted lines |
| 158 | * to be disabled and hence not get in the way. |
| 159 | **/ |
| 160 | struct iio_scan_el { |
| 161 | struct device_attribute dev_attr; |
| 162 | unsigned int number; |
| 163 | int bit_count; |
| 164 | unsigned int label; |
| 165 | |
| 166 | int (*set_state)(struct iio_scan_el *scanel, |
| 167 | struct iio_dev *dev_info, |
| 168 | bool state); |
| 169 | }; |
| 170 | |
| 171 | #define to_iio_scan_el(_dev_attr) \ |
| 172 | container_of(_dev_attr, struct iio_scan_el, dev_attr); |
| 173 | |
| 174 | /** |
| 175 | * iio_scan_el_store() - sysfs scan element selection interface |
| 176 | * @dev: the target device |
| 177 | * @attr: the device attribute that is being processed |
| 178 | * @buf: input from userspace |
| 179 | * @len: length of input |
| 180 | * |
| 181 | * A generic function used to enable various scan elements. In some |
| 182 | * devices explicit read commands for each channel mean this is merely |
| 183 | * a software switch. In others this must actively disable the channel. |
| 184 | * Complexities occur when this interacts with data ready type triggers |
| 185 | * which may not reset unless every channel that is enabled is explicitly |
| 186 | * read. |
| 187 | **/ |
| 188 | ssize_t iio_scan_el_store(struct device *dev, struct device_attribute *attr, |
| 189 | const char *buf, size_t len); |
| 190 | /** |
| 191 | * iio_scal_el_show() - sysfs interface to query whether a scan element is |
| 192 | * is enabled or not |
| 193 | * @dev: the target device |
| 194 | * @attr: the device attribute that is being processed |
| 195 | * @buf: output buffer |
| 196 | **/ |
| 197 | ssize_t iio_scan_el_show(struct device *dev, struct device_attribute *attr, |
| 198 | char *buf); |
| 199 | |
| 200 | ssize_t iio_scan_el_ts_store(struct device *dev, struct device_attribute *attr, |
| 201 | const char *buf, size_t len); |
| 202 | |
| 203 | ssize_t iio_scan_el_ts_show(struct device *dev, struct device_attribute *attr, |
| 204 | char *buf); |
| 205 | /** |
| 206 | * IIO_SCAN_EL_C - declare and initialize a scan element with a control func |
| 207 | * |
| 208 | * @_name: identifying name. Resulting struct is iio_scan_el_##_name, |
| 209 | * sysfs element, _name##_en. |
| 210 | * @_number: unique id number for the scan element. |
| 211 | * @_bits: number of bits in the scan element result (used in mixed bit |
| 212 | * length devices). |
| 213 | * @_label: indentification variable used by drivers. Often a reg address. |
| 214 | * @_controlfunc: function used to notify hardware of whether state changes |
| 215 | **/ |
| 216 | #define IIO_SCAN_EL_C(_name, _number, _bits, _label, _controlfunc) \ |
| 217 | struct iio_scan_el iio_scan_el_##_name = { \ |
| 218 | .dev_attr = __ATTR(_number##_##_name##_en, \ |
| 219 | S_IRUGO | S_IWUSR, \ |
| 220 | iio_scan_el_show, \ |
| 221 | iio_scan_el_store), \ |
| 222 | .number = _number, \ |
| 223 | .bit_count = _bits, \ |
| 224 | .label = _label, \ |
| 225 | .set_state = _controlfunc, \ |
| 226 | } |
| 227 | |
| 228 | #define IIO_SCAN_NAMED_EL_C(_name, _string, _number, _bits, _label, _cf) \ |
| 229 | struct iio_scan_el iio_scan_el_##_name = { \ |
| 230 | .dev_attr = __ATTR(_number##_##_string##_en, \ |
| 231 | S_IRUGO | S_IWUSR, \ |
| 232 | iio_scan_el_show, \ |
| 233 | iio_scan_el_store), \ |
| 234 | .number = _number, \ |
| 235 | .bit_count = _bits, \ |
| 236 | .label = _label, \ |
| 237 | .set_state = _cf, \ |
| 238 | } |
| 239 | |
| 240 | /** |
| 241 | * IIO_SCAN_EL_TIMESTAMP - declare a special scan element for timestamps |
| 242 | * |
| 243 | * Odd one out. Handled slightly differently from other scan elements. |
| 244 | **/ |
| 245 | #define IIO_SCAN_EL_TIMESTAMP(number) \ |
| 246 | struct iio_scan_el iio_scan_el_timestamp = { \ |
| 247 | .dev_attr = __ATTR(number##_timestamp_en, \ |
| 248 | S_IRUGO | S_IWUSR, \ |
| 249 | iio_scan_el_ts_show, \ |
| 250 | iio_scan_el_ts_store), \ |
| 251 | } |
| 252 | |
| 253 | static inline void iio_put_ring_buffer(struct iio_ring_buffer *ring) |
| 254 | { |
| 255 | put_device(&ring->dev); |
| 256 | }; |
| 257 | |
| 258 | #define to_iio_ring_buffer(d) \ |
| 259 | container_of(d, struct iio_ring_buffer, dev) |
| 260 | #define access_dev_to_iio_ring_buffer(d) \ |
| 261 | container_of(d, struct iio_ring_buffer, access_dev) |
| 262 | int iio_ring_buffer_register(struct iio_ring_buffer *ring, int id); |
| 263 | void iio_ring_buffer_unregister(struct iio_ring_buffer *ring); |
| 264 | |
| 265 | ssize_t iio_read_ring_length(struct device *dev, |
| 266 | struct device_attribute *attr, |
| 267 | char *buf); |
| 268 | ssize_t iio_write_ring_length(struct device *dev, |
| 269 | struct device_attribute *attr, |
| 270 | const char *buf, |
| 271 | size_t len); |
| 272 | ssize_t iio_read_ring_bps(struct device *dev, |
| 273 | struct device_attribute *attr, |
| 274 | char *buf); |
| 275 | ssize_t iio_store_ring_enable(struct device *dev, |
| 276 | struct device_attribute *attr, |
| 277 | const char *buf, |
| 278 | size_t len); |
| 279 | ssize_t iio_show_ring_enable(struct device *dev, |
| 280 | struct device_attribute *attr, |
| 281 | char *buf); |
| 282 | #define IIO_RING_LENGTH_ATTR DEVICE_ATTR(length, S_IRUGO | S_IWUSR, \ |
| 283 | iio_read_ring_length, \ |
| 284 | iio_write_ring_length) |
| 285 | #define IIO_RING_BPS_ATTR DEVICE_ATTR(bps, S_IRUGO | S_IWUSR, \ |
| 286 | iio_read_ring_bps, NULL) |
| 287 | #define IIO_RING_ENABLE_ATTR DEVICE_ATTR(ring_enable, S_IRUGO | S_IWUSR, \ |
| 288 | iio_show_ring_enable, \ |
| 289 | iio_store_ring_enable) |
| 290 | |
| 291 | #endif /* _IIO_RING_GENERIC_H_ */ |