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1// SPDX-License-Identifier: (GPL-2.0 OR BSD-3-Clause)
2
3#include <linux/irq.h>
4#include <linux/module.h>
5#include <linux/ntb.h>
6#include <linux/msi.h>
7#include <linux/pci.h>
8
9struct ntb_msi {
10 u64 base_addr;
11 u64 end_addr;
12
13 void (*desc_changed)(void *ctx);
14
15 u32 __iomem *peer_mws[];
16};
17
18/**
19 * ntb_msi_init() - Initialize the MSI context
20 * @ntb: NTB device context
21 *
22 * This function must be called before any other ntb_msi function.
23 * It initializes the context for MSI operations and maps
24 * the peer memory windows.
25 *
26 * This function reserves the last N outbound memory windows (where N
27 * is the number of peers).
28 *
29 * Return: Zero on success, otherwise a negative error number.
30 */
31int ntb_msi_init(struct ntb_dev *ntb,
32 void (*desc_changed)(void *ctx))
33{
34 phys_addr_t mw_phys_addr;
35 resource_size_t mw_size;
36 int peer_widx;
37 int peers;
38 int ret;
39 int i;
40
41 peers = ntb_peer_port_count(ntb);
42 if (peers <= 0)
43 return -EINVAL;
44
45 ntb->msi = devm_kzalloc(&ntb->dev, struct_size(ntb->msi, peer_mws, peers),
46 GFP_KERNEL);
47 if (!ntb->msi)
48 return -ENOMEM;
49
50 ntb->msi->desc_changed = desc_changed;
51
52 for (i = 0; i < peers; i++) {
53 peer_widx = ntb_peer_mw_count(ntb) - 1 - i;
54
55 ret = ntb_peer_mw_get_addr(ntb, peer_widx, &mw_phys_addr,
56 &mw_size);
57 if (ret)
58 goto unroll;
59
60 ntb->msi->peer_mws[i] = devm_ioremap(&ntb->dev, mw_phys_addr,
61 mw_size);
62 if (!ntb->msi->peer_mws[i]) {
63 ret = -EFAULT;
64 goto unroll;
65 }
66 }
67
68 return 0;
69
70unroll:
71 for (i = 0; i < peers; i++)
72 if (ntb->msi->peer_mws[i])
73 devm_iounmap(&ntb->dev, ntb->msi->peer_mws[i]);
74
75 devm_kfree(&ntb->dev, ntb->msi);
76 ntb->msi = NULL;
77 return ret;
78}
79EXPORT_SYMBOL(ntb_msi_init);
80
81/**
82 * ntb_msi_setup_mws() - Initialize the MSI inbound memory windows
83 * @ntb: NTB device context
84 *
85 * This function sets up the required inbound memory windows. It should be
86 * called from a work function after a link up event.
87 *
88 * Over the entire network, this function will reserves the last N
89 * inbound memory windows for each peer (where N is the number of peers).
90 *
91 * ntb_msi_init() must be called before this function.
92 *
93 * Return: Zero on success, otherwise a negative error number.
94 */
95int ntb_msi_setup_mws(struct ntb_dev *ntb)
96{
97 struct msi_desc *desc;
98 u64 addr;
99 int peer, peer_widx;
100 resource_size_t addr_align, size_align, size_max;
101 resource_size_t mw_size = SZ_32K;
102 resource_size_t mw_min_size = mw_size;
103 int i;
104 int ret;
105
106 if (!ntb->msi)
107 return -EINVAL;
108
109 scoped_guard (msi_descs_lock, &ntb->pdev->dev) {
110 desc = msi_first_desc(&ntb->pdev->dev, MSI_DESC_ASSOCIATED);
111 addr = desc->msg.address_lo + ((uint64_t)desc->msg.address_hi << 32);
112 }
113
114 for (peer = 0; peer < ntb_peer_port_count(ntb); peer++) {
115 peer_widx = ntb_peer_highest_mw_idx(ntb, peer);
116 if (peer_widx < 0)
117 return peer_widx;
118
119 ret = ntb_mw_get_align(ntb, peer, peer_widx, &addr_align,
120 NULL, NULL);
121 if (ret)
122 return ret;
123
124 addr &= ~(addr_align - 1);
125 }
126
127 for (peer = 0; peer < ntb_peer_port_count(ntb); peer++) {
128 peer_widx = ntb_peer_highest_mw_idx(ntb, peer);
129 if (peer_widx < 0) {
130 ret = peer_widx;
131 goto error_out;
132 }
133
134 ret = ntb_mw_get_align(ntb, peer, peer_widx, NULL,
135 &size_align, &size_max);
136 if (ret)
137 goto error_out;
138
139 mw_size = round_up(mw_size, size_align);
140 mw_size = max(mw_size, size_max);
141 if (mw_size < mw_min_size)
142 mw_min_size = mw_size;
143
144 ret = ntb_mw_set_trans(ntb, peer, peer_widx,
145 addr, mw_size);
146 if (ret)
147 goto error_out;
148 }
149
150 ntb->msi->base_addr = addr;
151 ntb->msi->end_addr = addr + mw_min_size;
152
153 return 0;
154
155error_out:
156 for (i = 0; i < peer; i++) {
157 peer_widx = ntb_peer_highest_mw_idx(ntb, peer);
158 if (peer_widx < 0)
159 continue;
160
161 ntb_mw_clear_trans(ntb, i, peer_widx);
162 }
163
164 return ret;
165}
166EXPORT_SYMBOL(ntb_msi_setup_mws);
167
168/**
169 * ntb_msi_clear_mws() - Clear all inbound memory windows
170 * @ntb: NTB device context
171 *
172 * This function tears down the resources used by ntb_msi_setup_mws().
173 */
174void ntb_msi_clear_mws(struct ntb_dev *ntb)
175{
176 int peer;
177 int peer_widx;
178
179 for (peer = 0; peer < ntb_peer_port_count(ntb); peer++) {
180 peer_widx = ntb_peer_highest_mw_idx(ntb, peer);
181 if (peer_widx < 0)
182 continue;
183
184 ntb_mw_clear_trans(ntb, peer, peer_widx);
185 }
186}
187EXPORT_SYMBOL(ntb_msi_clear_mws);
188
189struct ntb_msi_devres {
190 struct ntb_dev *ntb;
191 struct msi_desc *entry;
192 struct ntb_msi_desc *msi_desc;
193};
194
195static int ntb_msi_set_desc(struct ntb_dev *ntb, struct msi_desc *entry,
196 struct ntb_msi_desc *msi_desc)
197{
198 u64 addr;
199
200 addr = entry->msg.address_lo +
201 ((uint64_t)entry->msg.address_hi << 32);
202
203 if (addr < ntb->msi->base_addr || addr >= ntb->msi->end_addr) {
204 dev_warn_once(&ntb->dev,
205 "IRQ %d: MSI Address not within the memory window (%llx, [%llx %llx])\n",
206 entry->irq, addr, ntb->msi->base_addr,
207 ntb->msi->end_addr);
208 return -EFAULT;
209 }
210
211 msi_desc->addr_offset = addr - ntb->msi->base_addr;
212 msi_desc->data = entry->msg.data;
213
214 return 0;
215}
216
217static void ntb_msi_write_msg(struct msi_desc *entry, void *data)
218{
219 struct ntb_msi_devres *dr = data;
220
221 WARN_ON(ntb_msi_set_desc(dr->ntb, entry, dr->msi_desc));
222
223 if (dr->ntb->msi->desc_changed)
224 dr->ntb->msi->desc_changed(dr->ntb->ctx);
225}
226
227static void ntbm_msi_callback_release(struct device *dev, void *res)
228{
229 struct ntb_msi_devres *dr = res;
230
231 dr->entry->write_msi_msg = NULL;
232 dr->entry->write_msi_msg_data = NULL;
233}
234
235static int ntbm_msi_setup_callback(struct ntb_dev *ntb, struct msi_desc *entry,
236 struct ntb_msi_desc *msi_desc)
237{
238 struct ntb_msi_devres *dr;
239
240 dr = devres_alloc(ntbm_msi_callback_release,
241 sizeof(struct ntb_msi_devres), GFP_KERNEL);
242 if (!dr)
243 return -ENOMEM;
244
245 dr->ntb = ntb;
246 dr->entry = entry;
247 dr->msi_desc = msi_desc;
248
249 devres_add(&ntb->dev, dr);
250
251 dr->entry->write_msi_msg = ntb_msi_write_msg;
252 dr->entry->write_msi_msg_data = dr;
253
254 return 0;
255}
256
257/**
258 * ntbm_msi_request_threaded_irq() - allocate an MSI interrupt
259 * @ntb: NTB device context
260 * @handler: Function to be called when the IRQ occurs
261 * @thread_fn: Function to be called in a threaded interrupt context. NULL
262 * for clients which handle everything in @handler
263 * @name: An ascii name for the claiming device, dev_name(dev) if NULL
264 * @dev_id: A cookie passed back to the handler function
265 * @msi_desc: MSI descriptor data which triggers the interrupt
266 *
267 * This function assigns an interrupt handler to an unused
268 * MSI interrupt and returns the descriptor used to trigger
269 * it. The descriptor can then be sent to a peer to trigger
270 * the interrupt.
271 *
272 * The interrupt resource is managed with devres so it will
273 * be automatically freed when the NTB device is torn down.
274 *
275 * If an IRQ allocated with this function needs to be freed
276 * separately, ntbm_free_irq() must be used.
277 *
278 * Return: IRQ number assigned on success, otherwise a negative error number.
279 */
280int ntbm_msi_request_threaded_irq(struct ntb_dev *ntb, irq_handler_t handler,
281 irq_handler_t thread_fn,
282 const char *name, void *dev_id,
283 struct ntb_msi_desc *msi_desc)
284{
285 struct device *dev = &ntb->pdev->dev;
286 struct msi_desc *entry;
287 int ret;
288
289 if (!ntb->msi)
290 return -EINVAL;
291
292 guard(msi_descs_lock)(dev);
293 msi_for_each_desc(entry, dev, MSI_DESC_ASSOCIATED) {
294 if (irq_has_action(entry->irq))
295 continue;
296
297 ret = devm_request_threaded_irq(&ntb->dev, entry->irq, handler,
298 thread_fn, 0, name, dev_id);
299 if (ret)
300 continue;
301
302 if (ntb_msi_set_desc(ntb, entry, msi_desc)) {
303 devm_free_irq(&ntb->dev, entry->irq, dev_id);
304 continue;
305 }
306
307 ret = ntbm_msi_setup_callback(ntb, entry, msi_desc);
308 if (ret) {
309 devm_free_irq(&ntb->dev, entry->irq, dev_id);
310 return ret;
311 }
312 return entry->irq;
313 }
314 return -ENODEV;
315}
316EXPORT_SYMBOL(ntbm_msi_request_threaded_irq);
317
318/**
319 * ntb_msi_peer_trigger() - Trigger an interrupt handler on a peer
320 * @ntb: NTB device context
321 * @peer: Peer index
322 * @desc: MSI descriptor data which triggers the interrupt
323 *
324 * This function triggers an interrupt on a peer. It requires
325 * the descriptor structure to have been passed from that peer
326 * by some other means.
327 *
328 * Return: Zero on success, otherwise a negative error number.
329 */
330int ntb_msi_peer_trigger(struct ntb_dev *ntb, int peer,
331 struct ntb_msi_desc *desc)
332{
333 int idx;
334
335 if (!ntb->msi)
336 return -EINVAL;
337
338 idx = desc->addr_offset / sizeof(*ntb->msi->peer_mws[peer]);
339
340 iowrite32(desc->data, &ntb->msi->peer_mws[peer][idx]);
341
342 return 0;
343}
344EXPORT_SYMBOL(ntb_msi_peer_trigger);