xref: /linux/drivers/cxl/cxl.h (revision 0cac60c776a6bd15fbadc1c6c5c079b9a0c39634)
1 /* SPDX-License-Identifier: GPL-2.0-only */
2 /* Copyright(c) 2020 Intel Corporation. */
3 
4 #ifndef __CXL_H__
5 #define __CXL_H__
6 
7 #include <linux/libnvdimm.h>
8 #include <linux/bitfield.h>
9 #include <linux/bitops.h>
10 #include <linux/log2.h>
11 #include <linux/io.h>
12 
13 /**
14  * DOC: cxl objects
15  *
16  * The CXL core objects like ports, decoders, and regions are shared
17  * between the subsystem drivers cxl_acpi, cxl_pci, and core drivers
18  * (port-driver, region-driver, nvdimm object-drivers... etc).
19  */
20 
21 /* CXL 2.0 8.2.4 CXL Component Register Layout and Definition */
22 #define CXL_COMPONENT_REG_BLOCK_SIZE SZ_64K
23 
24 /* CXL 2.0 8.2.5 CXL.cache and CXL.mem Registers*/
25 #define CXL_CM_OFFSET 0x1000
26 #define CXL_CM_CAP_HDR_OFFSET 0x0
27 #define   CXL_CM_CAP_HDR_ID_MASK GENMASK(15, 0)
28 #define     CM_CAP_HDR_CAP_ID 1
29 #define   CXL_CM_CAP_HDR_VERSION_MASK GENMASK(19, 16)
30 #define     CM_CAP_HDR_CAP_VERSION 1
31 #define   CXL_CM_CAP_HDR_CACHE_MEM_VERSION_MASK GENMASK(23, 20)
32 #define     CM_CAP_HDR_CACHE_MEM_VERSION 1
33 #define   CXL_CM_CAP_HDR_ARRAY_SIZE_MASK GENMASK(31, 24)
34 #define CXL_CM_CAP_PTR_MASK GENMASK(31, 20)
35 
36 #define   CXL_CM_CAP_CAP_ID_RAS 0x2
37 #define   CXL_CM_CAP_CAP_ID_HDM 0x5
38 #define   CXL_CM_CAP_CAP_HDM_VERSION 1
39 
40 /* HDM decoders CXL 2.0 8.2.5.12 CXL HDM Decoder Capability Structure */
41 #define CXL_HDM_DECODER_CAP_OFFSET 0x0
42 #define   CXL_HDM_DECODER_COUNT_MASK GENMASK(3, 0)
43 #define   CXL_HDM_DECODER_TARGET_COUNT_MASK GENMASK(7, 4)
44 #define   CXL_HDM_DECODER_INTERLEAVE_11_8 BIT(8)
45 #define   CXL_HDM_DECODER_INTERLEAVE_14_12 BIT(9)
46 #define CXL_HDM_DECODER_CTRL_OFFSET 0x4
47 #define   CXL_HDM_DECODER_ENABLE BIT(1)
48 #define CXL_HDM_DECODER0_BASE_LOW_OFFSET(i) (0x20 * (i) + 0x10)
49 #define CXL_HDM_DECODER0_BASE_HIGH_OFFSET(i) (0x20 * (i) + 0x14)
50 #define CXL_HDM_DECODER0_SIZE_LOW_OFFSET(i) (0x20 * (i) + 0x18)
51 #define CXL_HDM_DECODER0_SIZE_HIGH_OFFSET(i) (0x20 * (i) + 0x1c)
52 #define CXL_HDM_DECODER0_CTRL_OFFSET(i) (0x20 * (i) + 0x20)
53 #define   CXL_HDM_DECODER0_CTRL_IG_MASK GENMASK(3, 0)
54 #define   CXL_HDM_DECODER0_CTRL_IW_MASK GENMASK(7, 4)
55 #define   CXL_HDM_DECODER0_CTRL_LOCK BIT(8)
56 #define   CXL_HDM_DECODER0_CTRL_COMMIT BIT(9)
57 #define   CXL_HDM_DECODER0_CTRL_COMMITTED BIT(10)
58 #define   CXL_HDM_DECODER0_CTRL_COMMIT_ERROR BIT(11)
59 #define   CXL_HDM_DECODER0_CTRL_TYPE BIT(12)
60 #define CXL_HDM_DECODER0_TL_LOW(i) (0x20 * (i) + 0x24)
61 #define CXL_HDM_DECODER0_TL_HIGH(i) (0x20 * (i) + 0x28)
62 #define CXL_HDM_DECODER0_SKIP_LOW(i) CXL_HDM_DECODER0_TL_LOW(i)
63 #define CXL_HDM_DECODER0_SKIP_HIGH(i) CXL_HDM_DECODER0_TL_HIGH(i)
64 
65 /* HDM decoder control register constants CXL 3.0 8.2.5.19.7 */
66 #define CXL_DECODER_MIN_GRANULARITY 256
67 #define CXL_DECODER_MAX_ENCODED_IG 6
68 
69 static inline int cxl_hdm_decoder_count(u32 cap_hdr)
70 {
71 	int val = FIELD_GET(CXL_HDM_DECODER_COUNT_MASK, cap_hdr);
72 
73 	return val ? val * 2 : 1;
74 }
75 
76 /* Encode defined in CXL 2.0 8.2.5.12.7 HDM Decoder Control Register */
77 static inline int eig_to_granularity(u16 eig, unsigned int *granularity)
78 {
79 	if (eig > CXL_DECODER_MAX_ENCODED_IG)
80 		return -EINVAL;
81 	*granularity = CXL_DECODER_MIN_GRANULARITY << eig;
82 	return 0;
83 }
84 
85 /* Encode defined in CXL ECN "3, 6, 12 and 16-way memory Interleaving" */
86 static inline int eiw_to_ways(u8 eiw, unsigned int *ways)
87 {
88 	switch (eiw) {
89 	case 0 ... 4:
90 		*ways = 1 << eiw;
91 		break;
92 	case 8 ... 10:
93 		*ways = 3 << (eiw - 8);
94 		break;
95 	default:
96 		return -EINVAL;
97 	}
98 
99 	return 0;
100 }
101 
102 static inline int granularity_to_eig(int granularity, u16 *eig)
103 {
104 	if (granularity > SZ_16K || granularity < CXL_DECODER_MIN_GRANULARITY ||
105 	    !is_power_of_2(granularity))
106 		return -EINVAL;
107 	*eig = ilog2(granularity) - 8;
108 	return 0;
109 }
110 
111 static inline int ways_to_eiw(unsigned int ways, u8 *eiw)
112 {
113 	if (ways > 16)
114 		return -EINVAL;
115 	if (is_power_of_2(ways)) {
116 		*eiw = ilog2(ways);
117 		return 0;
118 	}
119 	if (ways % 3)
120 		return -EINVAL;
121 	ways /= 3;
122 	if (!is_power_of_2(ways))
123 		return -EINVAL;
124 	*eiw = ilog2(ways) + 8;
125 	return 0;
126 }
127 
128 /* RAS Registers CXL 2.0 8.2.5.9 CXL RAS Capability Structure */
129 #define CXL_RAS_UNCORRECTABLE_STATUS_OFFSET 0x0
130 #define   CXL_RAS_UNCORRECTABLE_STATUS_MASK (GENMASK(16, 14) | GENMASK(11, 0))
131 #define CXL_RAS_UNCORRECTABLE_MASK_OFFSET 0x4
132 #define   CXL_RAS_UNCORRECTABLE_MASK_MASK (GENMASK(16, 14) | GENMASK(11, 0))
133 #define CXL_RAS_UNCORRECTABLE_SEVERITY_OFFSET 0x8
134 #define   CXL_RAS_UNCORRECTABLE_SEVERITY_MASK (GENMASK(16, 14) | GENMASK(11, 0))
135 #define CXL_RAS_CORRECTABLE_STATUS_OFFSET 0xC
136 #define   CXL_RAS_CORRECTABLE_STATUS_MASK GENMASK(6, 0)
137 #define CXL_RAS_CORRECTABLE_MASK_OFFSET 0x10
138 #define   CXL_RAS_CORRECTABLE_MASK_MASK GENMASK(6, 0)
139 #define CXL_RAS_CAP_CONTROL_OFFSET 0x14
140 #define CXL_RAS_CAP_CONTROL_FE_MASK GENMASK(5, 0)
141 #define CXL_RAS_HEADER_LOG_OFFSET 0x18
142 #define CXL_RAS_CAPABILITY_LENGTH 0x58
143 
144 /* CXL 2.0 8.2.8.1 Device Capabilities Array Register */
145 #define CXLDEV_CAP_ARRAY_OFFSET 0x0
146 #define   CXLDEV_CAP_ARRAY_CAP_ID 0
147 #define   CXLDEV_CAP_ARRAY_ID_MASK GENMASK_ULL(15, 0)
148 #define   CXLDEV_CAP_ARRAY_COUNT_MASK GENMASK_ULL(47, 32)
149 /* CXL 2.0 8.2.8.2 CXL Device Capability Header Register */
150 #define CXLDEV_CAP_HDR_CAP_ID_MASK GENMASK(15, 0)
151 /* CXL 2.0 8.2.8.2.1 CXL Device Capabilities */
152 #define CXLDEV_CAP_CAP_ID_DEVICE_STATUS 0x1
153 #define CXLDEV_CAP_CAP_ID_PRIMARY_MAILBOX 0x2
154 #define CXLDEV_CAP_CAP_ID_SECONDARY_MAILBOX 0x3
155 #define CXLDEV_CAP_CAP_ID_MEMDEV 0x4000
156 
157 /* CXL 2.0 8.2.8.4 Mailbox Registers */
158 #define CXLDEV_MBOX_CAPS_OFFSET 0x00
159 #define   CXLDEV_MBOX_CAP_PAYLOAD_SIZE_MASK GENMASK(4, 0)
160 #define CXLDEV_MBOX_CTRL_OFFSET 0x04
161 #define   CXLDEV_MBOX_CTRL_DOORBELL BIT(0)
162 #define CXLDEV_MBOX_CMD_OFFSET 0x08
163 #define   CXLDEV_MBOX_CMD_COMMAND_OPCODE_MASK GENMASK_ULL(15, 0)
164 #define   CXLDEV_MBOX_CMD_PAYLOAD_LENGTH_MASK GENMASK_ULL(36, 16)
165 #define CXLDEV_MBOX_STATUS_OFFSET 0x10
166 #define   CXLDEV_MBOX_STATUS_RET_CODE_MASK GENMASK_ULL(47, 32)
167 #define CXLDEV_MBOX_BG_CMD_STATUS_OFFSET 0x18
168 #define CXLDEV_MBOX_PAYLOAD_OFFSET 0x20
169 
170 /*
171  * Using struct_group() allows for per register-block-type helper routines,
172  * without requiring block-type agnostic code to include the prefix.
173  */
174 struct cxl_regs {
175 	/*
176 	 * Common set of CXL Component register block base pointers
177 	 * @hdm_decoder: CXL 2.0 8.2.5.12 CXL HDM Decoder Capability Structure
178 	 * @ras: CXL 2.0 8.2.5.9 CXL RAS Capability Structure
179 	 */
180 	struct_group_tagged(cxl_component_regs, component,
181 		void __iomem *hdm_decoder;
182 		void __iomem *ras;
183 	);
184 	/*
185 	 * Common set of CXL Device register block base pointers
186 	 * @status: CXL 2.0 8.2.8.3 Device Status Registers
187 	 * @mbox: CXL 2.0 8.2.8.4 Mailbox Registers
188 	 * @memdev: CXL 2.0 8.2.8.5 Memory Device Registers
189 	 */
190 	struct_group_tagged(cxl_device_regs, device_regs,
191 		void __iomem *status, *mbox, *memdev;
192 	);
193 };
194 
195 struct cxl_reg_map {
196 	bool valid;
197 	int id;
198 	unsigned long offset;
199 	unsigned long size;
200 };
201 
202 struct cxl_component_reg_map {
203 	struct cxl_reg_map hdm_decoder;
204 	struct cxl_reg_map ras;
205 };
206 
207 struct cxl_device_reg_map {
208 	struct cxl_reg_map status;
209 	struct cxl_reg_map mbox;
210 	struct cxl_reg_map memdev;
211 };
212 
213 /**
214  * struct cxl_register_map - DVSEC harvested register block mapping parameters
215  * @base: virtual base of the register-block-BAR + @block_offset
216  * @resource: physical resource base of the register block
217  * @max_size: maximum mapping size to perform register search
218  * @reg_type: see enum cxl_regloc_type
219  * @component_map: cxl_reg_map for component registers
220  * @device_map: cxl_reg_maps for device registers
221  */
222 struct cxl_register_map {
223 	void __iomem *base;
224 	resource_size_t resource;
225 	resource_size_t max_size;
226 	u8 reg_type;
227 	union {
228 		struct cxl_component_reg_map component_map;
229 		struct cxl_device_reg_map device_map;
230 	};
231 };
232 
233 void cxl_probe_component_regs(struct device *dev, void __iomem *base,
234 			      struct cxl_component_reg_map *map);
235 void cxl_probe_device_regs(struct device *dev, void __iomem *base,
236 			   struct cxl_device_reg_map *map);
237 int cxl_map_component_regs(struct device *dev, struct cxl_component_regs *regs,
238 			   struct cxl_register_map *map,
239 			   unsigned long map_mask);
240 int cxl_map_device_regs(struct device *dev, struct cxl_device_regs *regs,
241 			struct cxl_register_map *map);
242 
243 enum cxl_regloc_type;
244 int cxl_find_regblock(struct pci_dev *pdev, enum cxl_regloc_type type,
245 		      struct cxl_register_map *map);
246 
247 enum cxl_rcrb {
248 	CXL_RCRB_DOWNSTREAM,
249 	CXL_RCRB_UPSTREAM,
250 };
251 resource_size_t cxl_rcrb_to_component(struct device *dev,
252 				      resource_size_t rcrb,
253 				      enum cxl_rcrb which);
254 
255 #define CXL_RESOURCE_NONE ((resource_size_t) -1)
256 #define CXL_TARGET_STRLEN 20
257 
258 /*
259  * cxl_decoder flags that define the type of memory / devices this
260  * decoder supports as well as configuration lock status See "CXL 2.0
261  * 8.2.5.12.7 CXL HDM Decoder 0 Control Register" for details.
262  */
263 #define CXL_DECODER_F_RAM   BIT(0)
264 #define CXL_DECODER_F_PMEM  BIT(1)
265 #define CXL_DECODER_F_TYPE2 BIT(2)
266 #define CXL_DECODER_F_TYPE3 BIT(3)
267 #define CXL_DECODER_F_LOCK  BIT(4)
268 #define CXL_DECODER_F_ENABLE    BIT(5)
269 #define CXL_DECODER_F_MASK  GENMASK(5, 0)
270 
271 enum cxl_decoder_type {
272        CXL_DECODER_ACCELERATOR = 2,
273        CXL_DECODER_EXPANDER = 3,
274 };
275 
276 /*
277  * Current specification goes up to 8, double that seems a reasonable
278  * software max for the foreseeable future
279  */
280 #define CXL_DECODER_MAX_INTERLEAVE 16
281 
282 
283 /**
284  * struct cxl_decoder - Common CXL HDM Decoder Attributes
285  * @dev: this decoder's device
286  * @id: kernel device name id
287  * @hpa_range: Host physical address range mapped by this decoder
288  * @interleave_ways: number of cxl_dports in this decode
289  * @interleave_granularity: data stride per dport
290  * @target_type: accelerator vs expander (type2 vs type3) selector
291  * @region: currently assigned region for this decoder
292  * @flags: memory type capabilities and locking
293  * @commit: device/decoder-type specific callback to commit settings to hw
294  * @reset: device/decoder-type specific callback to reset hw settings
295 */
296 struct cxl_decoder {
297 	struct device dev;
298 	int id;
299 	struct range hpa_range;
300 	int interleave_ways;
301 	int interleave_granularity;
302 	enum cxl_decoder_type target_type;
303 	struct cxl_region *region;
304 	unsigned long flags;
305 	int (*commit)(struct cxl_decoder *cxld);
306 	int (*reset)(struct cxl_decoder *cxld);
307 };
308 
309 /*
310  * CXL_DECODER_DEAD prevents endpoints from being reattached to regions
311  * while cxld_unregister() is running
312  */
313 enum cxl_decoder_mode {
314 	CXL_DECODER_NONE,
315 	CXL_DECODER_RAM,
316 	CXL_DECODER_PMEM,
317 	CXL_DECODER_MIXED,
318 	CXL_DECODER_DEAD,
319 };
320 
321 /**
322  * struct cxl_endpoint_decoder - Endpoint  / SPA to DPA decoder
323  * @cxld: base cxl_decoder_object
324  * @dpa_res: actively claimed DPA span of this decoder
325  * @skip: offset into @dpa_res where @cxld.hpa_range maps
326  * @mode: which memory type / access-mode-partition this decoder targets
327  * @pos: interleave position in @cxld.region
328  */
329 struct cxl_endpoint_decoder {
330 	struct cxl_decoder cxld;
331 	struct resource *dpa_res;
332 	resource_size_t skip;
333 	enum cxl_decoder_mode mode;
334 	int pos;
335 };
336 
337 /**
338  * struct cxl_switch_decoder - Switch specific CXL HDM Decoder
339  * @cxld: base cxl_decoder object
340  * @target_lock: coordinate coherent reads of the target list
341  * @nr_targets: number of elements in @target
342  * @target: active ordered target list in current decoder configuration
343  *
344  * The 'switch' decoder type represents the decoder instances of cxl_port's that
345  * route from the root of a CXL memory decode topology to the endpoints. They
346  * come in two flavors, root-level decoders, statically defined by platform
347  * firmware, and mid-level decoders, where interleave-granularity,
348  * interleave-width, and the target list are mutable.
349  */
350 struct cxl_switch_decoder {
351 	struct cxl_decoder cxld;
352 	seqlock_t target_lock;
353 	int nr_targets;
354 	struct cxl_dport *target[];
355 };
356 
357 struct cxl_root_decoder;
358 typedef struct cxl_dport *(*cxl_calc_hb_fn)(struct cxl_root_decoder *cxlrd,
359 					    int pos);
360 
361 /**
362  * struct cxl_root_decoder - Static platform CXL address decoder
363  * @res: host / parent resource for region allocations
364  * @region_id: region id for next region provisioning event
365  * @calc_hb: which host bridge covers the n'th position by granularity
366  * @platform_data: platform specific configuration data
367  * @cxlsd: base cxl switch decoder
368  */
369 struct cxl_root_decoder {
370 	struct resource *res;
371 	atomic_t region_id;
372 	cxl_calc_hb_fn calc_hb;
373 	void *platform_data;
374 	struct cxl_switch_decoder cxlsd;
375 };
376 
377 /*
378  * enum cxl_config_state - State machine for region configuration
379  * @CXL_CONFIG_IDLE: Any sysfs attribute can be written freely
380  * @CXL_CONFIG_INTERLEAVE_ACTIVE: region size has been set, no more
381  * changes to interleave_ways or interleave_granularity
382  * @CXL_CONFIG_ACTIVE: All targets have been added the region is now
383  * active
384  * @CXL_CONFIG_RESET_PENDING: see commit_store()
385  * @CXL_CONFIG_COMMIT: Soft-config has been committed to hardware
386  */
387 enum cxl_config_state {
388 	CXL_CONFIG_IDLE,
389 	CXL_CONFIG_INTERLEAVE_ACTIVE,
390 	CXL_CONFIG_ACTIVE,
391 	CXL_CONFIG_RESET_PENDING,
392 	CXL_CONFIG_COMMIT,
393 };
394 
395 /**
396  * struct cxl_region_params - region settings
397  * @state: allow the driver to lockdown further parameter changes
398  * @uuid: unique id for persistent regions
399  * @interleave_ways: number of endpoints in the region
400  * @interleave_granularity: capacity each endpoint contributes to a stripe
401  * @res: allocated iomem capacity for this region
402  * @targets: active ordered targets in current decoder configuration
403  * @nr_targets: number of targets
404  *
405  * State transitions are protected by the cxl_region_rwsem
406  */
407 struct cxl_region_params {
408 	enum cxl_config_state state;
409 	uuid_t uuid;
410 	int interleave_ways;
411 	int interleave_granularity;
412 	struct resource *res;
413 	struct cxl_endpoint_decoder *targets[CXL_DECODER_MAX_INTERLEAVE];
414 	int nr_targets;
415 };
416 
417 /*
418  * Flag whether this region needs to have its HPA span synchronized with
419  * CPU cache state at region activation time.
420  */
421 #define CXL_REGION_F_INCOHERENT 0
422 
423 /**
424  * struct cxl_region - CXL region
425  * @dev: This region's device
426  * @id: This region's id. Id is globally unique across all regions
427  * @mode: Endpoint decoder allocation / access mode
428  * @type: Endpoint decoder target type
429  * @cxl_nvb: nvdimm bridge for coordinating @cxlr_pmem setup / shutdown
430  * @cxlr_pmem: (for pmem regions) cached copy of the nvdimm bridge
431  * @flags: Region state flags
432  * @params: active + config params for the region
433  */
434 struct cxl_region {
435 	struct device dev;
436 	int id;
437 	enum cxl_decoder_mode mode;
438 	enum cxl_decoder_type type;
439 	struct cxl_nvdimm_bridge *cxl_nvb;
440 	struct cxl_pmem_region *cxlr_pmem;
441 	unsigned long flags;
442 	struct cxl_region_params params;
443 };
444 
445 struct cxl_nvdimm_bridge {
446 	int id;
447 	struct device dev;
448 	struct cxl_port *port;
449 	struct nvdimm_bus *nvdimm_bus;
450 	struct nvdimm_bus_descriptor nd_desc;
451 };
452 
453 #define CXL_DEV_ID_LEN 19
454 
455 struct cxl_nvdimm {
456 	struct device dev;
457 	struct cxl_memdev *cxlmd;
458 	u8 dev_id[CXL_DEV_ID_LEN]; /* for nvdimm, string of 'serial' */
459 };
460 
461 struct cxl_pmem_region_mapping {
462 	struct cxl_memdev *cxlmd;
463 	struct cxl_nvdimm *cxl_nvd;
464 	u64 start;
465 	u64 size;
466 	int position;
467 };
468 
469 struct cxl_pmem_region {
470 	struct device dev;
471 	struct cxl_region *cxlr;
472 	struct nd_region *nd_region;
473 	struct range hpa_range;
474 	int nr_mappings;
475 	struct cxl_pmem_region_mapping mapping[];
476 };
477 
478 /**
479  * struct cxl_port - logical collection of upstream port devices and
480  *		     downstream port devices to construct a CXL memory
481  *		     decode hierarchy.
482  * @dev: this port's device
483  * @uport: PCI or platform device implementing the upstream port capability
484  * @host_bridge: Shortcut to the platform attach point for this port
485  * @id: id for port device-name
486  * @dports: cxl_dport instances referenced by decoders
487  * @endpoints: cxl_ep instances, endpoints that are a descendant of this port
488  * @regions: cxl_region_ref instances, regions mapped by this port
489  * @parent_dport: dport that points to this port in the parent
490  * @decoder_ida: allocator for decoder ids
491  * @nr_dports: number of entries in @dports
492  * @hdm_end: track last allocated HDM decoder instance for allocation ordering
493  * @commit_end: cursor to track highest committed decoder for commit ordering
494  * @component_reg_phys: component register capability base address (optional)
495  * @dead: last ep has been removed, force port re-creation
496  * @depth: How deep this port is relative to the root. depth 0 is the root.
497  * @cdat: Cached CDAT data
498  * @cdat_available: Should a CDAT attribute be available in sysfs
499  */
500 struct cxl_port {
501 	struct device dev;
502 	struct device *uport;
503 	struct device *host_bridge;
504 	int id;
505 	struct xarray dports;
506 	struct xarray endpoints;
507 	struct xarray regions;
508 	struct cxl_dport *parent_dport;
509 	struct ida decoder_ida;
510 	int nr_dports;
511 	int hdm_end;
512 	int commit_end;
513 	resource_size_t component_reg_phys;
514 	bool dead;
515 	unsigned int depth;
516 	struct cxl_cdat {
517 		void *table;
518 		size_t length;
519 	} cdat;
520 	bool cdat_available;
521 };
522 
523 static inline struct cxl_dport *
524 cxl_find_dport_by_dev(struct cxl_port *port, const struct device *dport_dev)
525 {
526 	return xa_load(&port->dports, (unsigned long)dport_dev);
527 }
528 
529 /**
530  * struct cxl_dport - CXL downstream port
531  * @dport: PCI bridge or firmware device representing the downstream link
532  * @port_id: unique hardware identifier for dport in decoder target list
533  * @component_reg_phys: downstream port component registers
534  * @rcrb: base address for the Root Complex Register Block
535  * @rch: Indicate whether this dport was enumerated in RCH or VH mode
536  * @port: reference to cxl_port that contains this downstream port
537  */
538 struct cxl_dport {
539 	struct device *dport;
540 	int port_id;
541 	resource_size_t component_reg_phys;
542 	resource_size_t rcrb;
543 	bool rch;
544 	struct cxl_port *port;
545 };
546 
547 /**
548  * struct cxl_ep - track an endpoint's interest in a port
549  * @ep: device that hosts a generic CXL endpoint (expander or accelerator)
550  * @dport: which dport routes to this endpoint on @port
551  * @next: cxl switch port across the link attached to @dport NULL if
552  *	  attached to an endpoint
553  */
554 struct cxl_ep {
555 	struct device *ep;
556 	struct cxl_dport *dport;
557 	struct cxl_port *next;
558 };
559 
560 /**
561  * struct cxl_region_ref - track a region's interest in a port
562  * @port: point in topology to install this reference
563  * @decoder: decoder assigned for @region in @port
564  * @region: region for this reference
565  * @endpoints: cxl_ep references for region members beneath @port
566  * @nr_targets_set: track how many targets have been programmed during setup
567  * @nr_eps: number of endpoints beneath @port
568  * @nr_targets: number of distinct targets needed to reach @nr_eps
569  */
570 struct cxl_region_ref {
571 	struct cxl_port *port;
572 	struct cxl_decoder *decoder;
573 	struct cxl_region *region;
574 	struct xarray endpoints;
575 	int nr_targets_set;
576 	int nr_eps;
577 	int nr_targets;
578 };
579 
580 /*
581  * The platform firmware device hosting the root is also the top of the
582  * CXL port topology. All other CXL ports have another CXL port as their
583  * parent and their ->uport / host device is out-of-line of the port
584  * ancestry.
585  */
586 static inline bool is_cxl_root(struct cxl_port *port)
587 {
588 	return port->uport == port->dev.parent;
589 }
590 
591 bool is_cxl_port(struct device *dev);
592 struct cxl_port *to_cxl_port(struct device *dev);
593 struct pci_bus;
594 int devm_cxl_register_pci_bus(struct device *host, struct device *uport,
595 			      struct pci_bus *bus);
596 struct pci_bus *cxl_port_to_pci_bus(struct cxl_port *port);
597 struct cxl_port *devm_cxl_add_port(struct device *host, struct device *uport,
598 				   resource_size_t component_reg_phys,
599 				   struct cxl_dport *parent_dport);
600 struct cxl_port *find_cxl_root(struct device *dev);
601 int devm_cxl_enumerate_ports(struct cxl_memdev *cxlmd);
602 void cxl_bus_rescan(void);
603 void cxl_bus_drain(void);
604 struct cxl_port *cxl_mem_find_port(struct cxl_memdev *cxlmd,
605 				   struct cxl_dport **dport);
606 bool schedule_cxl_memdev_detach(struct cxl_memdev *cxlmd);
607 
608 struct cxl_dport *devm_cxl_add_dport(struct cxl_port *port,
609 				     struct device *dport, int port_id,
610 				     resource_size_t component_reg_phys);
611 struct cxl_dport *devm_cxl_add_rch_dport(struct cxl_port *port,
612 					 struct device *dport_dev, int port_id,
613 					 resource_size_t component_reg_phys,
614 					 resource_size_t rcrb);
615 
616 struct cxl_decoder *to_cxl_decoder(struct device *dev);
617 struct cxl_root_decoder *to_cxl_root_decoder(struct device *dev);
618 struct cxl_endpoint_decoder *to_cxl_endpoint_decoder(struct device *dev);
619 bool is_root_decoder(struct device *dev);
620 bool is_endpoint_decoder(struct device *dev);
621 struct cxl_root_decoder *cxl_root_decoder_alloc(struct cxl_port *port,
622 						unsigned int nr_targets,
623 						cxl_calc_hb_fn calc_hb);
624 struct cxl_dport *cxl_hb_modulo(struct cxl_root_decoder *cxlrd, int pos);
625 struct cxl_switch_decoder *cxl_switch_decoder_alloc(struct cxl_port *port,
626 						    unsigned int nr_targets);
627 int cxl_decoder_add(struct cxl_decoder *cxld, int *target_map);
628 struct cxl_endpoint_decoder *cxl_endpoint_decoder_alloc(struct cxl_port *port);
629 int cxl_decoder_add_locked(struct cxl_decoder *cxld, int *target_map);
630 int cxl_decoder_autoremove(struct device *host, struct cxl_decoder *cxld);
631 int cxl_endpoint_autoremove(struct cxl_memdev *cxlmd, struct cxl_port *endpoint);
632 
633 struct cxl_hdm;
634 struct cxl_hdm *devm_cxl_setup_hdm(struct cxl_port *port);
635 int devm_cxl_enumerate_decoders(struct cxl_hdm *cxlhdm);
636 int devm_cxl_add_passthrough_decoder(struct cxl_port *port);
637 
638 bool is_cxl_region(struct device *dev);
639 
640 extern struct bus_type cxl_bus_type;
641 
642 struct cxl_driver {
643 	const char *name;
644 	int (*probe)(struct device *dev);
645 	void (*remove)(struct device *dev);
646 	struct device_driver drv;
647 	int id;
648 };
649 
650 static inline struct cxl_driver *to_cxl_drv(struct device_driver *drv)
651 {
652 	return container_of(drv, struct cxl_driver, drv);
653 }
654 
655 int __cxl_driver_register(struct cxl_driver *cxl_drv, struct module *owner,
656 			  const char *modname);
657 #define cxl_driver_register(x) __cxl_driver_register(x, THIS_MODULE, KBUILD_MODNAME)
658 void cxl_driver_unregister(struct cxl_driver *cxl_drv);
659 
660 #define module_cxl_driver(__cxl_driver) \
661 	module_driver(__cxl_driver, cxl_driver_register, cxl_driver_unregister)
662 
663 #define CXL_DEVICE_NVDIMM_BRIDGE	1
664 #define CXL_DEVICE_NVDIMM		2
665 #define CXL_DEVICE_PORT			3
666 #define CXL_DEVICE_ROOT			4
667 #define CXL_DEVICE_MEMORY_EXPANDER	5
668 #define CXL_DEVICE_REGION		6
669 #define CXL_DEVICE_PMEM_REGION		7
670 
671 #define MODULE_ALIAS_CXL(type) MODULE_ALIAS("cxl:t" __stringify(type) "*")
672 #define CXL_MODALIAS_FMT "cxl:t%d"
673 
674 struct cxl_nvdimm_bridge *to_cxl_nvdimm_bridge(struct device *dev);
675 struct cxl_nvdimm_bridge *devm_cxl_add_nvdimm_bridge(struct device *host,
676 						     struct cxl_port *port);
677 struct cxl_nvdimm *to_cxl_nvdimm(struct device *dev);
678 bool is_cxl_nvdimm(struct device *dev);
679 bool is_cxl_nvdimm_bridge(struct device *dev);
680 int devm_cxl_add_nvdimm(struct cxl_memdev *cxlmd);
681 struct cxl_nvdimm_bridge *cxl_find_nvdimm_bridge(struct device *dev);
682 
683 #ifdef CONFIG_CXL_REGION
684 bool is_cxl_pmem_region(struct device *dev);
685 struct cxl_pmem_region *to_cxl_pmem_region(struct device *dev);
686 #else
687 static inline bool is_cxl_pmem_region(struct device *dev)
688 {
689 	return false;
690 }
691 static inline struct cxl_pmem_region *to_cxl_pmem_region(struct device *dev)
692 {
693 	return NULL;
694 }
695 #endif
696 
697 /*
698  * Unit test builds overrides this to __weak, find the 'strong' version
699  * of these symbols in tools/testing/cxl/.
700  */
701 #ifndef __mock
702 #define __mock static
703 #endif
704 
705 #endif /* __CXL_H__ */
706