Martyn Welch | bf39f9a | 2009-08-28 11:28:56 +0100 | [diff] [blame] | 1 | VME Device Driver API |
| 2 | ===================== |
| 3 | |
| 4 | Driver registration |
| 5 | =================== |
| 6 | |
| 7 | As with other subsystems within the Linux kernel, VME device drivers register |
| 8 | with the VME subsystem, typically called from the devices init routine. This is |
Lucas De Marchi | 25985ed | 2011-03-30 22:57:33 -0300 | [diff] [blame] | 9 | achieved via a call to the following function: |
Martyn Welch | bf39f9a | 2009-08-28 11:28:56 +0100 | [diff] [blame] | 10 | |
| 11 | int vme_register_driver (struct vme_driver *driver); |
| 12 | |
| 13 | If driver registration is successful this function returns zero, if an error |
| 14 | occurred a negative error code will be returned. |
| 15 | |
| 16 | A pointer to a structure of type 'vme_driver' must be provided to the |
| 17 | registration function. The structure is as follows: |
| 18 | |
| 19 | struct vme_driver { |
| 20 | struct list_head node; |
| 21 | char *name; |
| 22 | const struct vme_device_id *bind_table; |
| 23 | int (*probe) (struct device *, int, int); |
| 24 | int (*remove) (struct device *, int, int); |
| 25 | void (*shutdown) (void); |
| 26 | struct device_driver driver; |
| 27 | }; |
| 28 | |
| 29 | At the minimum, the '.name', '.probe' and '.bind_table' elements of this |
| 30 | structure should be correctly set. The '.name' element is a pointer to a string |
| 31 | holding the device driver's name. The '.probe' element should contain a pointer |
| 32 | to the probe routine. |
| 33 | |
| 34 | The arguments of the probe routine are as follows: |
| 35 | |
| 36 | probe(struct device *dev, int bus, int slot); |
| 37 | |
| 38 | The '.bind_table' is a pointer to an array of type 'vme_device_id': |
| 39 | |
| 40 | struct vme_device_id { |
| 41 | int bus; |
| 42 | int slot; |
| 43 | }; |
| 44 | |
| 45 | Each structure in this array should provide a bus and slot number where the core |
| 46 | should probe, using the driver's probe routine, for a device on the specified |
| 47 | VME bus. |
| 48 | |
| 49 | The VME subsystem supports a single VME driver per 'slot'. There are considered |
| 50 | to be 32 slots per bus, one for each slot-ID as defined in the ANSI/VITA 1-1994 |
| 51 | specification and are analogious to the physical slots on the VME backplane. |
| 52 | |
| 53 | A function is also provided to unregister the driver from the VME core and is |
| 54 | usually called from the device driver's exit routine: |
| 55 | |
| 56 | void vme_unregister_driver (struct vme_driver *driver); |
| 57 | |
| 58 | |
| 59 | Resource management |
| 60 | =================== |
| 61 | |
| 62 | Once a driver has registered with the VME core the provided probe routine will |
| 63 | be called for each of the bus/slot combination that becomes valid as VME buses |
| 64 | are themselves registered. The probe routine is passed a pointer to the devices |
| 65 | device structure. This pointer should be saved, it will be required for |
| 66 | requesting VME resources. |
| 67 | |
| 68 | The driver can request ownership of one or more master windows, slave windows |
| 69 | and/or dma channels. Rather than allowing the device driver to request a |
| 70 | specific window or DMA channel (which may be used by a different driver) this |
| 71 | driver allows a resource to be assigned based on the required attributes of the |
| 72 | driver in question: |
| 73 | |
| 74 | struct vme_resource * vme_master_request(struct device *dev, |
| 75 | vme_address_t aspace, vme_cycle_t cycle, vme_width_t width); |
| 76 | |
| 77 | struct vme_resource * vme_slave_request(struct device *dev, |
| 78 | vme_address_t aspace, vme_cycle_t cycle); |
| 79 | |
Martyn Welch | 4f723df | 2010-02-18 15:12:58 +0000 | [diff] [blame] | 80 | struct vme_resource *vme_dma_request(struct device *dev, |
| 81 | vme_dma_route_t route); |
Martyn Welch | bf39f9a | 2009-08-28 11:28:56 +0100 | [diff] [blame] | 82 | |
| 83 | For slave windows these attributes are split into those of type 'vme_address_t' |
Martyn Welch | 4f723df | 2010-02-18 15:12:58 +0000 | [diff] [blame] | 84 | and 'vme_cycle_t'. Master windows add a further set of attributes |
| 85 | 'vme_cycle_t'. These attributes are defined as bitmasks and as such any |
| 86 | combination of the attributes can be requested for a single window, the core |
| 87 | will assign a window that meets the requirements, returning a pointer of type |
| 88 | vme_resource that should be used to identify the allocated resource when it is |
| 89 | used. For DMA controllers, the request function requires the potential |
| 90 | direction of any transfers to be provided in the route attributes. This is |
| 91 | typically VME-to-MEM and/or MEM-to-VME, though some hardware can support |
| 92 | VME-to-VME and MEM-to-MEM transfers as well as test pattern generation. If an |
| 93 | unallocated window fitting the requirements can not be found a NULL pointer |
| 94 | will be returned. |
Martyn Welch | bf39f9a | 2009-08-28 11:28:56 +0100 | [diff] [blame] | 95 | |
| 96 | Functions are also provided to free window allocations once they are no longer |
| 97 | required. These functions should be passed the pointer to the resource provided |
| 98 | during resource allocation: |
| 99 | |
| 100 | void vme_master_free(struct vme_resource *res); |
| 101 | |
| 102 | void vme_slave_free(struct vme_resource *res); |
| 103 | |
| 104 | void vme_dma_free(struct vme_resource *res); |
| 105 | |
| 106 | |
| 107 | Master windows |
| 108 | ============== |
| 109 | |
| 110 | Master windows provide access from the local processor[s] out onto the VME bus. |
Lucas De Marchi | 25985ed | 2011-03-30 22:57:33 -0300 | [diff] [blame] | 111 | The number of windows available and the available access modes is dependent on |
Martyn Welch | bf39f9a | 2009-08-28 11:28:56 +0100 | [diff] [blame] | 112 | the underlying chipset. A window must be configured before it can be used. |
| 113 | |
| 114 | |
| 115 | Master window configuration |
| 116 | --------------------------- |
| 117 | |
| 118 | Once a master window has been assigned the following functions can be used to |
| 119 | configure it and retrieve the current settings: |
| 120 | |
| 121 | int vme_master_set (struct vme_resource *res, int enabled, |
| 122 | unsigned long long base, unsigned long long size, |
| 123 | vme_address_t aspace, vme_cycle_t cycle, vme_width_t width); |
| 124 | |
| 125 | int vme_master_get (struct vme_resource *res, int *enabled, |
| 126 | unsigned long long *base, unsigned long long *size, |
| 127 | vme_address_t *aspace, vme_cycle_t *cycle, vme_width_t *width); |
| 128 | |
| 129 | The address spaces, transfer widths and cycle types are the same as described |
| 130 | under resource management, however some of the options are mutually exclusive. |
| 131 | For example, only one address space may be specified. |
| 132 | |
| 133 | These functions return 0 on success or an error code should the call fail. |
| 134 | |
| 135 | |
| 136 | Master window access |
| 137 | -------------------- |
| 138 | |
| 139 | The following functions can be used to read from and write to configured master |
| 140 | windows. These functions return the number of bytes copied: |
| 141 | |
| 142 | ssize_t vme_master_read(struct vme_resource *res, void *buf, |
| 143 | size_t count, loff_t offset); |
| 144 | |
| 145 | ssize_t vme_master_write(struct vme_resource *res, void *buf, |
| 146 | size_t count, loff_t offset); |
| 147 | |
| 148 | In addition to simple reads and writes, a function is provided to do a |
| 149 | read-modify-write transaction. This function returns the original value of the |
| 150 | VME bus location : |
| 151 | |
| 152 | unsigned int vme_master_rmw (struct vme_resource *res, |
| 153 | unsigned int mask, unsigned int compare, unsigned int swap, |
| 154 | loff_t offset); |
| 155 | |
| 156 | This functions by reading the offset, applying the mask. If the bits selected in |
| 157 | the mask match with the values of the corresponding bits in the compare field, |
| 158 | the value of swap is written the specified offset. |
| 159 | |
| 160 | |
| 161 | Slave windows |
| 162 | ============= |
| 163 | |
| 164 | Slave windows provide devices on the VME bus access into mapped portions of the |
| 165 | local memory. The number of windows available and the access modes that can be |
Lucas De Marchi | 25985ed | 2011-03-30 22:57:33 -0300 | [diff] [blame] | 166 | used is dependent on the underlying chipset. A window must be configured before |
Martyn Welch | bf39f9a | 2009-08-28 11:28:56 +0100 | [diff] [blame] | 167 | it can be used. |
| 168 | |
| 169 | |
| 170 | Slave window configuration |
| 171 | -------------------------- |
| 172 | |
| 173 | Once a slave window has been assigned the following functions can be used to |
| 174 | configure it and retrieve the current settings: |
| 175 | |
| 176 | int vme_slave_set (struct vme_resource *res, int enabled, |
| 177 | unsigned long long base, unsigned long long size, |
| 178 | dma_addr_t mem, vme_address_t aspace, vme_cycle_t cycle); |
| 179 | |
| 180 | int vme_slave_get (struct vme_resource *res, int *enabled, |
| 181 | unsigned long long *base, unsigned long long *size, |
| 182 | dma_addr_t *mem, vme_address_t *aspace, vme_cycle_t *cycle); |
| 183 | |
| 184 | The address spaces, transfer widths and cycle types are the same as described |
| 185 | under resource management, however some of the options are mutually exclusive. |
| 186 | For example, only one address space may be specified. |
| 187 | |
| 188 | These functions return 0 on success or an error code should the call fail. |
| 189 | |
| 190 | |
| 191 | Slave window buffer allocation |
| 192 | ------------------------------ |
| 193 | |
| 194 | Functions are provided to allow the user to allocate and free a contiguous |
| 195 | buffers which will be accessible by the VME bridge. These functions do not have |
| 196 | to be used, other methods can be used to allocate a buffer, though care must be |
| 197 | taken to ensure that they are contiguous and accessible by the VME bridge: |
| 198 | |
| 199 | void * vme_alloc_consistent(struct vme_resource *res, size_t size, |
| 200 | dma_addr_t *mem); |
| 201 | |
| 202 | void vme_free_consistent(struct vme_resource *res, size_t size, |
| 203 | void *virt, dma_addr_t mem); |
| 204 | |
| 205 | |
| 206 | Slave window access |
| 207 | ------------------- |
| 208 | |
| 209 | Slave windows map local memory onto the VME bus, the standard methods for |
| 210 | accessing memory should be used. |
| 211 | |
| 212 | |
| 213 | DMA channels |
| 214 | ============ |
| 215 | |
| 216 | The VME DMA transfer provides the ability to run link-list DMA transfers. The |
| 217 | API introduces the concept of DMA lists. Each DMA list is a link-list which can |
| 218 | be passed to a DMA controller. Multiple lists can be created, extended, |
| 219 | executed, reused and destroyed. |
| 220 | |
| 221 | |
| 222 | List Management |
| 223 | --------------- |
| 224 | |
| 225 | The following functions are provided to create and destroy DMA lists. Execution |
| 226 | of a list will not automatically destroy the list, thus enabling a list to be |
| 227 | reused for repetitive tasks: |
| 228 | |
| 229 | struct vme_dma_list *vme_new_dma_list(struct vme_resource *res); |
| 230 | |
| 231 | int vme_dma_list_free(struct vme_dma_list *list); |
| 232 | |
| 233 | |
| 234 | List Population |
| 235 | --------------- |
| 236 | |
| 237 | An item can be added to a list using the following function ( the source and |
| 238 | destination attributes need to be created before calling this function, this is |
| 239 | covered under "Transfer Attributes"): |
| 240 | |
| 241 | int vme_dma_list_add(struct vme_dma_list *list, |
| 242 | struct vme_dma_attr *src, struct vme_dma_attr *dest, |
| 243 | size_t count); |
| 244 | |
Martyn Welch | 4f723df | 2010-02-18 15:12:58 +0000 | [diff] [blame] | 245 | NOTE: The detailed attributes of the transfers source and destination |
| 246 | are not checked until an entry is added to a DMA list, the request |
| 247 | for a DMA channel purely checks the directions in which the |
| 248 | controller is expected to transfer data. As a result it is |
| 249 | possible for this call to return an error, for example if the |
| 250 | source or destination is in an unsupported VME address space. |
Martyn Welch | bf39f9a | 2009-08-28 11:28:56 +0100 | [diff] [blame] | 251 | |
| 252 | Transfer Attributes |
| 253 | ------------------- |
| 254 | |
| 255 | The attributes for the source and destination are handled separately from adding |
| 256 | an item to a list. This is due to the diverse attributes required for each type |
| 257 | of source and destination. There are functions to create attributes for PCI, VME |
| 258 | and pattern sources and destinations (where appropriate): |
| 259 | |
| 260 | Pattern source: |
| 261 | |
| 262 | struct vme_dma_attr *vme_dma_pattern_attribute(u32 pattern, |
| 263 | vme_pattern_t type); |
| 264 | |
| 265 | PCI source or destination: |
| 266 | |
| 267 | struct vme_dma_attr *vme_dma_pci_attribute(dma_addr_t mem); |
| 268 | |
| 269 | VME source or destination: |
| 270 | |
| 271 | struct vme_dma_attr *vme_dma_vme_attribute(unsigned long long base, |
| 272 | vme_address_t aspace, vme_cycle_t cycle, vme_width_t width); |
| 273 | |
| 274 | The following function should be used to free an attribute: |
| 275 | |
| 276 | void vme_dma_free_attribute(struct vme_dma_attr *attr); |
| 277 | |
| 278 | |
| 279 | List Execution |
| 280 | -------------- |
| 281 | |
| 282 | The following function queues a list for execution. The function will return |
| 283 | once the list has been executed: |
| 284 | |
| 285 | int vme_dma_list_exec(struct vme_dma_list *list); |
| 286 | |
| 287 | |
| 288 | Interrupts |
| 289 | ========== |
| 290 | |
| 291 | The VME API provides functions to attach and detach callbacks to specific VME |
| 292 | level and status ID combinations and for the generation of VME interrupts with |
| 293 | specific VME level and status IDs. |
| 294 | |
| 295 | |
| 296 | Attaching Interrupt Handlers |
| 297 | ---------------------------- |
| 298 | |
| 299 | The following functions can be used to attach and free a specific VME level and |
| 300 | status ID combination. Any given combination can only be assigned a single |
| 301 | callback function. A void pointer parameter is provided, the value of which is |
| 302 | passed to the callback function, the use of this pointer is user undefined: |
| 303 | |
Martyn Welch | c813f59 | 2009-10-29 16:34:54 +0000 | [diff] [blame] | 304 | int vme_irq_request(struct device *dev, int level, int statid, |
Martyn Welch | bf39f9a | 2009-08-28 11:28:56 +0100 | [diff] [blame] | 305 | void (*callback)(int, int, void *), void *priv); |
| 306 | |
Martyn Welch | c813f59 | 2009-10-29 16:34:54 +0000 | [diff] [blame] | 307 | void vme_irq_free(struct device *dev, int level, int statid); |
Martyn Welch | bf39f9a | 2009-08-28 11:28:56 +0100 | [diff] [blame] | 308 | |
| 309 | The callback parameters are as follows. Care must be taken in writing a callback |
| 310 | function, callback functions run in interrupt context: |
| 311 | |
| 312 | void callback(int level, int statid, void *priv); |
| 313 | |
| 314 | |
| 315 | Interrupt Generation |
| 316 | -------------------- |
| 317 | |
| 318 | The following function can be used to generate a VME interrupt at a given VME |
| 319 | level and VME status ID: |
| 320 | |
Martyn Welch | c813f59 | 2009-10-29 16:34:54 +0000 | [diff] [blame] | 321 | int vme_irq_generate(struct device *dev, int level, int statid); |
Martyn Welch | bf39f9a | 2009-08-28 11:28:56 +0100 | [diff] [blame] | 322 | |
| 323 | |
| 324 | Location monitors |
| 325 | ================= |
| 326 | |
| 327 | The VME API provides the following functionality to configure the location |
| 328 | monitor. |
| 329 | |
| 330 | |
| 331 | Location Monitor Management |
| 332 | --------------------------- |
| 333 | |
| 334 | The following functions are provided to request the use of a block of location |
| 335 | monitors and to free them after they are no longer required: |
| 336 | |
| 337 | struct vme_resource * vme_lm_request(struct device *dev); |
| 338 | |
| 339 | void vme_lm_free(struct vme_resource * res); |
| 340 | |
| 341 | Each block may provide a number of location monitors, monitoring adjacent |
| 342 | locations. The following function can be used to determine how many locations |
| 343 | are provided: |
| 344 | |
| 345 | int vme_lm_count(struct vme_resource * res); |
| 346 | |
| 347 | |
| 348 | Location Monitor Configuration |
| 349 | ------------------------------ |
| 350 | |
| 351 | Once a bank of location monitors has been allocated, the following functions |
| 352 | are provided to configure the location and mode of the location monitor: |
| 353 | |
| 354 | int vme_lm_set(struct vme_resource *res, unsigned long long base, |
| 355 | vme_address_t aspace, vme_cycle_t cycle); |
| 356 | |
| 357 | int vme_lm_get(struct vme_resource *res, unsigned long long *base, |
| 358 | vme_address_t *aspace, vme_cycle_t *cycle); |
| 359 | |
| 360 | |
| 361 | Location Monitor Use |
| 362 | -------------------- |
| 363 | |
| 364 | The following functions allow a callback to be attached and detached from each |
| 365 | location monitor location. Each location monitor can monitor a number of |
| 366 | adjacent locations: |
| 367 | |
| 368 | int vme_lm_attach(struct vme_resource *res, int num, |
| 369 | void (*callback)(int)); |
| 370 | |
| 371 | int vme_lm_detach(struct vme_resource *res, int num); |
| 372 | |
| 373 | The callback function is declared as follows. |
| 374 | |
| 375 | void callback(int num); |
| 376 | |
| 377 | |
| 378 | Slot Detection |
| 379 | ============== |
| 380 | |
| 381 | This function returns the slot ID of the provided bridge. |
| 382 | |
| 383 | int vme_slot_get(struct device *dev); |