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	size_t struct_size;
 37	int peer_widx;
 38	int peers;
 39	int ret;
 40	int i;
 41
 42	peers = ntb_peer_port_count(ntb);
 43	if (peers <= 0)
 44		return -EINVAL;
 45
 46	struct_size = sizeof(*ntb->msi) + sizeof(*ntb->msi->peer_mws) * peers;
 47
 48	ntb->msi = devm_kzalloc(&ntb->dev, struct_size, GFP_KERNEL);
 49	if (!ntb->msi)
 50		return -ENOMEM;
 51
 52	ntb->msi->desc_changed = desc_changed;
 53
 54	for (i = 0; i < peers; i++) {
 55		peer_widx = ntb_peer_mw_count(ntb) - 1 - i;
 56
 57		ret = ntb_peer_mw_get_addr(ntb, peer_widx, &mw_phys_addr,
 58					   &mw_size);
 59		if (ret)
 60			goto unroll;
 61
 62		ntb->msi->peer_mws[i] = devm_ioremap(&ntb->dev, mw_phys_addr,
 63						     mw_size);
 64		if (!ntb->msi->peer_mws[i]) {
 65			ret = -EFAULT;
 66			goto unroll;
 67		}
 68	}
 69
 70	return 0;
 71
 72unroll:
 73	for (i = 0; i < peers; i++)
 74		if (ntb->msi->peer_mws[i])
 75			devm_iounmap(&ntb->dev, ntb->msi->peer_mws[i]);
 76
 77	devm_kfree(&ntb->dev, ntb->msi);
 78	ntb->msi = NULL;
 79	return ret;
 80}
 81EXPORT_SYMBOL(ntb_msi_init);
 82
 83/**
 84 * ntb_msi_setup_mws() - Initialize the MSI inbound memory windows
 85 * @ntb:	NTB device context
 86 *
 87 * This function sets up the required inbound memory windows. It should be
 88 * called from a work function after a link up event.
 89 *
 90 * Over the entire network, this function will reserves the last N
 91 * inbound memory windows for each peer (where N is the number of peers).
 92 *
 93 * ntb_msi_init() must be called before this function.
 94 *
 95 * Return: Zero on success, otherwise a negative error number.
 96 */
 97int ntb_msi_setup_mws(struct ntb_dev *ntb)
 98{
 99	struct msi_desc *desc;
100	u64 addr;
101	int peer, peer_widx;
102	resource_size_t addr_align, size_align, size_max;
103	resource_size_t mw_size = SZ_32K;
104	resource_size_t mw_min_size = mw_size;
105	int i;
106	int ret;
107
108	if (!ntb->msi)
109		return -EINVAL;
110
111	desc = first_msi_entry(&ntb->pdev->dev);
112	addr = desc->msg.address_lo + ((uint64_t)desc->msg.address_hi << 32);
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 * @devname:    An ascii name for the claiming device, dev_name(dev) if NULL
264 * @dev_id:     A cookie passed back to the handler function
265 *
266 * This function assigns an interrupt handler to an unused
267 * MSI interrupt and returns the descriptor used to trigger
268 * it. The descriptor can then be sent to a peer to trigger
269 * the interrupt.
270 *
271 * The interrupt resource is managed with devres so it will
272 * be automatically freed when the NTB device is torn down.
273 *
274 * If an IRQ allocated with this function needs to be freed
275 * separately, ntbm_free_irq() must be used.
276 *
277 * Return: IRQ number assigned on success, otherwise a negative error number.
278 */
279int ntbm_msi_request_threaded_irq(struct ntb_dev *ntb, irq_handler_t handler,
280				  irq_handler_t thread_fn,
281				  const char *name, void *dev_id,
282				  struct ntb_msi_desc *msi_desc)
283{
284	struct msi_desc *entry;
285	struct irq_desc *desc;
286	int ret;
287
288	if (!ntb->msi)
289		return -EINVAL;
290
291	for_each_pci_msi_entry(entry, ntb->pdev) {
292		desc = irq_to_desc(entry->irq);
293		if (desc->action)
294			continue;
295
296		ret = devm_request_threaded_irq(&ntb->dev, entry->irq, handler,
297						thread_fn, 0, name, dev_id);
298		if (ret)
299			continue;
300
301		if (ntb_msi_set_desc(ntb, entry, msi_desc)) {
302			devm_free_irq(&ntb->dev, entry->irq, dev_id);
303			continue;
304		}
305
306		ret = ntbm_msi_setup_callback(ntb, entry, msi_desc);
307		if (ret) {
308			devm_free_irq(&ntb->dev, entry->irq, dev_id);
309			return ret;
310		}
311
312
313		return entry->irq;
314	}
315
316	return -ENODEV;
317}
318EXPORT_SYMBOL(ntbm_msi_request_threaded_irq);
319
320static int ntbm_msi_callback_match(struct device *dev, void *res, void *data)
321{
322	struct ntb_dev *ntb = dev_ntb(dev);
323	struct ntb_msi_devres *dr = res;
324
325	return dr->ntb == ntb && dr->entry == data;
326}
327
328/**
329 * ntbm_msi_free_irq() - free an interrupt
330 * @ntb:	NTB device context
331 * @irq:	Interrupt line to free
332 * @dev_id:	Device identity to free
333 *
334 * This function should be used to manually free IRQs allocated with
335 * ntbm_request_[threaded_]irq().
336 */
337void ntbm_msi_free_irq(struct ntb_dev *ntb, unsigned int irq, void *dev_id)
338{
339	struct msi_desc *entry = irq_get_msi_desc(irq);
340
341	entry->write_msi_msg = NULL;
342	entry->write_msi_msg_data = NULL;
343
344	WARN_ON(devres_destroy(&ntb->dev, ntbm_msi_callback_release,
345			       ntbm_msi_callback_match, entry));
346
347	devm_free_irq(&ntb->dev, irq, dev_id);
348}
349EXPORT_SYMBOL(ntbm_msi_free_irq);
350
351/**
352 * ntb_msi_peer_trigger() - Trigger an interrupt handler on a peer
353 * @ntb:	NTB device context
354 * @peer:	Peer index
355 * @desc:	MSI descriptor data which triggers the interrupt
356 *
357 * This function triggers an interrupt on a peer. It requires
358 * the descriptor structure to have been passed from that peer
359 * by some other means.
360 *
361 * Return: Zero on success, otherwise a negative error number.
362 */
363int ntb_msi_peer_trigger(struct ntb_dev *ntb, int peer,
364			 struct ntb_msi_desc *desc)
365{
366	int idx;
367
368	if (!ntb->msi)
369		return -EINVAL;
370
371	idx = desc->addr_offset / sizeof(*ntb->msi->peer_mws[peer]);
372
373	iowrite32(desc->data, &ntb->msi->peer_mws[peer][idx]);
374
375	return 0;
376}
377EXPORT_SYMBOL(ntb_msi_peer_trigger);
378
379/**
380 * ntb_msi_peer_addr() - Get the DMA address to trigger a peer's MSI interrupt
381 * @ntb:	NTB device context
382 * @peer:	Peer index
383 * @desc:	MSI descriptor data which triggers the interrupt
384 * @msi_addr:   Physical address to trigger the interrupt
385 *
386 * This function allows using DMA engines to trigger an interrupt
387 * (for example, trigger an interrupt to process the data after
388 * sending it). To trigger the interrupt, write @desc.data to the address
389 * returned in @msi_addr
390 *
391 * Return: Zero on success, otherwise a negative error number.
392 */
393int ntb_msi_peer_addr(struct ntb_dev *ntb, int peer,
394		      struct ntb_msi_desc *desc,
395		      phys_addr_t *msi_addr)
396{
397	int peer_widx = ntb_peer_mw_count(ntb) - 1 - peer;
398	phys_addr_t mw_phys_addr;
399	int ret;
400
401	ret = ntb_peer_mw_get_addr(ntb, peer_widx, &mw_phys_addr, NULL);
402	if (ret)
403		return ret;
404
405	if (msi_addr)
406		*msi_addr = mw_phys_addr + desc->addr_offset;
407
408	return 0;
409}
410EXPORT_SYMBOL(ntb_msi_peer_addr);