1 /*
2  * Copyright 2014 IBM Corp.
3  *
4  * This program is free software; you can redistribute it and/or
5  * modify it under the terms of the GNU General Public License
6  * as published by the Free Software Foundation; either version
7  * 2 of the License, or (at your option) any later version.
8  */
9 
10 #include <linux/spinlock.h>
11 #include <linux/kernel.h>
12 #include <linux/module.h>
13 #include <linux/device.h>
14 #include <linux/mutex.h>
15 #include <linux/init.h>
16 #include <linux/list.h>
17 #include <linux/mm.h>
18 #include <linux/of.h>
19 #include <linux/slab.h>
20 #include <linux/idr.h>
21 #include <linux/pci.h>
22 #include <linux/sched/task.h>
23 
24 #include <asm/cputable.h>
25 #include <misc/cxl-base.h>
26 
27 #include "cxl.h"
28 #include "trace.h"
29 
30 static DEFINE_SPINLOCK(adapter_idr_lock);
31 static DEFINE_IDR(cxl_adapter_idr);
32 
33 uint cxl_verbose;
34 module_param_named(verbose, cxl_verbose, uint, 0600);
35 MODULE_PARM_DESC(verbose, "Enable verbose dmesg output");
36 
37 const struct cxl_backend_ops *cxl_ops;
38 
cxl_afu_slbia(struct cxl_afu * afu)39 int cxl_afu_slbia(struct cxl_afu *afu)
40 {
41 	unsigned long timeout = jiffies + (HZ * CXL_TIMEOUT);
42 
43 	pr_devel("cxl_afu_slbia issuing SLBIA command\n");
44 	cxl_p2n_write(afu, CXL_SLBIA_An, CXL_TLB_SLB_IQ_ALL);
45 	while (cxl_p2n_read(afu, CXL_SLBIA_An) & CXL_TLB_SLB_P) {
46 		if (time_after_eq(jiffies, timeout)) {
47 			dev_warn(&afu->dev, "WARNING: CXL AFU SLBIA timed out!\n");
48 			return -EBUSY;
49 		}
50 		/* If the adapter has gone down, we can assume that we
51 		 * will PERST it and that will invalidate everything.
52 		 */
53 		if (!cxl_ops->link_ok(afu->adapter, afu))
54 			return -EIO;
55 		cpu_relax();
56 	}
57 	return 0;
58 }
59 
_cxl_slbia(struct cxl_context * ctx,struct mm_struct * mm)60 static inline void _cxl_slbia(struct cxl_context *ctx, struct mm_struct *mm)
61 {
62 	unsigned long flags;
63 
64 	if (ctx->mm != mm)
65 		return;
66 
67 	pr_devel("%s matched mm - card: %i afu: %i pe: %i\n", __func__,
68 		 ctx->afu->adapter->adapter_num, ctx->afu->slice, ctx->pe);
69 
70 	spin_lock_irqsave(&ctx->sste_lock, flags);
71 	trace_cxl_slbia(ctx);
72 	memset(ctx->sstp, 0, ctx->sst_size);
73 	spin_unlock_irqrestore(&ctx->sste_lock, flags);
74 	mb();
75 	cxl_afu_slbia(ctx->afu);
76 }
77 
cxl_slbia_core(struct mm_struct * mm)78 static inline void cxl_slbia_core(struct mm_struct *mm)
79 {
80 	struct cxl *adapter;
81 	struct cxl_afu *afu;
82 	struct cxl_context *ctx;
83 	int card, slice, id;
84 
85 	pr_devel("%s called\n", __func__);
86 
87 	spin_lock(&adapter_idr_lock);
88 	idr_for_each_entry(&cxl_adapter_idr, adapter, card) {
89 		/* XXX: Make this lookup faster with link from mm to ctx */
90 		spin_lock(&adapter->afu_list_lock);
91 		for (slice = 0; slice < adapter->slices; slice++) {
92 			afu = adapter->afu[slice];
93 			if (!afu || !afu->enabled)
94 				continue;
95 			rcu_read_lock();
96 			idr_for_each_entry(&afu->contexts_idr, ctx, id)
97 				_cxl_slbia(ctx, mm);
98 			rcu_read_unlock();
99 		}
100 		spin_unlock(&adapter->afu_list_lock);
101 	}
102 	spin_unlock(&adapter_idr_lock);
103 }
104 
105 static struct cxl_calls cxl_calls = {
106 	.cxl_slbia = cxl_slbia_core,
107 	.owner = THIS_MODULE,
108 };
109 
cxl_alloc_sst(struct cxl_context * ctx)110 int cxl_alloc_sst(struct cxl_context *ctx)
111 {
112 	unsigned long vsid;
113 	u64 ea_mask, size, sstp0, sstp1;
114 
115 	sstp0 = 0;
116 	sstp1 = 0;
117 
118 	ctx->sst_size = PAGE_SIZE;
119 	ctx->sst_lru = 0;
120 	ctx->sstp = (struct cxl_sste *)get_zeroed_page(GFP_KERNEL);
121 	if (!ctx->sstp) {
122 		pr_err("cxl_alloc_sst: Unable to allocate segment table\n");
123 		return -ENOMEM;
124 	}
125 	pr_devel("SSTP allocated at 0x%p\n", ctx->sstp);
126 
127 	vsid  = get_kernel_vsid((u64)ctx->sstp, mmu_kernel_ssize) << 12;
128 
129 	sstp0 |= (u64)mmu_kernel_ssize << CXL_SSTP0_An_B_SHIFT;
130 	sstp0 |= (SLB_VSID_KERNEL | mmu_psize_defs[mmu_linear_psize].sllp) << 50;
131 
132 	size = (((u64)ctx->sst_size >> 8) - 1) << CXL_SSTP0_An_SegTableSize_SHIFT;
133 	if (unlikely(size & ~CXL_SSTP0_An_SegTableSize_MASK)) {
134 		WARN(1, "Impossible segment table size\n");
135 		return -EINVAL;
136 	}
137 	sstp0 |= size;
138 
139 	if (mmu_kernel_ssize == MMU_SEGSIZE_256M)
140 		ea_mask = 0xfffff00ULL;
141 	else
142 		ea_mask = 0xffffffff00ULL;
143 
144 	sstp0 |=  vsid >>     (50-14);  /*   Top 14 bits of VSID */
145 	sstp1 |= (vsid << (64-(50-14))) & ~ea_mask;
146 	sstp1 |= (u64)ctx->sstp & ea_mask;
147 	sstp1 |= CXL_SSTP1_An_V;
148 
149 	pr_devel("Looked up %#llx: slbfee. %#llx (ssize: %x, vsid: %#lx), copied to SSTP0: %#llx, SSTP1: %#llx\n",
150 			(u64)ctx->sstp, (u64)ctx->sstp & ESID_MASK, mmu_kernel_ssize, vsid, sstp0, sstp1);
151 
152 	/* Store calculated sstp hardware points for use later */
153 	ctx->sstp0 = sstp0;
154 	ctx->sstp1 = sstp1;
155 
156 	return 0;
157 }
158 
159 /* print buffer content as integers when debugging */
cxl_dump_debug_buffer(void * buf,size_t buf_len)160 void cxl_dump_debug_buffer(void *buf, size_t buf_len)
161 {
162 #ifdef DEBUG
163 	int i, *ptr;
164 
165 	/*
166 	 * We want to regroup up to 4 integers per line, which means they
167 	 * need to be in the same pr_devel() statement
168 	 */
169 	ptr = (int *) buf;
170 	for (i = 0; i * 4 < buf_len; i += 4) {
171 		if ((i + 3) * 4 < buf_len)
172 			pr_devel("%.8x %.8x %.8x %.8x\n", ptr[i], ptr[i + 1],
173 				ptr[i + 2], ptr[i + 3]);
174 		else if ((i + 2) * 4 < buf_len)
175 			pr_devel("%.8x %.8x %.8x\n", ptr[i], ptr[i + 1],
176 				ptr[i + 2]);
177 		else if ((i + 1) * 4 < buf_len)
178 			pr_devel("%.8x %.8x\n", ptr[i], ptr[i + 1]);
179 		else
180 			pr_devel("%.8x\n", ptr[i]);
181 	}
182 #endif /* DEBUG */
183 }
184 
185 /* Find a CXL adapter by it's number and increase it's refcount */
get_cxl_adapter(int num)186 struct cxl *get_cxl_adapter(int num)
187 {
188 	struct cxl *adapter;
189 
190 	spin_lock(&adapter_idr_lock);
191 	if ((adapter = idr_find(&cxl_adapter_idr, num)))
192 		get_device(&adapter->dev);
193 	spin_unlock(&adapter_idr_lock);
194 
195 	return adapter;
196 }
197 
cxl_alloc_adapter_nr(struct cxl * adapter)198 static int cxl_alloc_adapter_nr(struct cxl *adapter)
199 {
200 	int i;
201 
202 	idr_preload(GFP_KERNEL);
203 	spin_lock(&adapter_idr_lock);
204 	i = idr_alloc(&cxl_adapter_idr, adapter, 0, 0, GFP_NOWAIT);
205 	spin_unlock(&adapter_idr_lock);
206 	idr_preload_end();
207 	if (i < 0)
208 		return i;
209 
210 	adapter->adapter_num = i;
211 
212 	return 0;
213 }
214 
cxl_remove_adapter_nr(struct cxl * adapter)215 void cxl_remove_adapter_nr(struct cxl *adapter)
216 {
217 	idr_remove(&cxl_adapter_idr, adapter->adapter_num);
218 }
219 
cxl_alloc_adapter(void)220 struct cxl *cxl_alloc_adapter(void)
221 {
222 	struct cxl *adapter;
223 
224 	if (!(adapter = kzalloc(sizeof(struct cxl), GFP_KERNEL)))
225 		return NULL;
226 
227 	spin_lock_init(&adapter->afu_list_lock);
228 
229 	if (cxl_alloc_adapter_nr(adapter))
230 		goto err1;
231 
232 	if (dev_set_name(&adapter->dev, "card%i", adapter->adapter_num))
233 		goto err2;
234 
235 	/* start with context lock taken */
236 	atomic_set(&adapter->contexts_num, -1);
237 
238 	return adapter;
239 err2:
240 	cxl_remove_adapter_nr(adapter);
241 err1:
242 	kfree(adapter);
243 	return NULL;
244 }
245 
cxl_alloc_afu(struct cxl * adapter,int slice)246 struct cxl_afu *cxl_alloc_afu(struct cxl *adapter, int slice)
247 {
248 	struct cxl_afu *afu;
249 
250 	if (!(afu = kzalloc(sizeof(struct cxl_afu), GFP_KERNEL)))
251 		return NULL;
252 
253 	afu->adapter = adapter;
254 	afu->dev.parent = &adapter->dev;
255 	afu->dev.release = cxl_ops->release_afu;
256 	afu->slice = slice;
257 	idr_init(&afu->contexts_idr);
258 	mutex_init(&afu->contexts_lock);
259 	spin_lock_init(&afu->afu_cntl_lock);
260 	atomic_set(&afu->configured_state, -1);
261 	afu->prefault_mode = CXL_PREFAULT_NONE;
262 	afu->irqs_max = afu->adapter->user_irqs;
263 
264 	return afu;
265 }
266 
cxl_afu_select_best_mode(struct cxl_afu * afu)267 int cxl_afu_select_best_mode(struct cxl_afu *afu)
268 {
269 	if (afu->modes_supported & CXL_MODE_DIRECTED)
270 		return cxl_ops->afu_activate_mode(afu, CXL_MODE_DIRECTED);
271 
272 	if (afu->modes_supported & CXL_MODE_DEDICATED)
273 		return cxl_ops->afu_activate_mode(afu, CXL_MODE_DEDICATED);
274 
275 	dev_warn(&afu->dev, "No supported programming modes available\n");
276 	/* We don't fail this so the user can inspect sysfs */
277 	return 0;
278 }
279 
cxl_adapter_context_get(struct cxl * adapter)280 int cxl_adapter_context_get(struct cxl *adapter)
281 {
282 	int rc;
283 
284 	rc = atomic_inc_unless_negative(&adapter->contexts_num);
285 	return rc ? 0 : -EBUSY;
286 }
287 
cxl_adapter_context_put(struct cxl * adapter)288 void cxl_adapter_context_put(struct cxl *adapter)
289 {
290 	atomic_dec_if_positive(&adapter->contexts_num);
291 }
292 
cxl_adapter_context_lock(struct cxl * adapter)293 int cxl_adapter_context_lock(struct cxl *adapter)
294 {
295 	int rc;
296 	/* no active contexts -> contexts_num == 0 */
297 	rc = atomic_cmpxchg(&adapter->contexts_num, 0, -1);
298 	return rc ? -EBUSY : 0;
299 }
300 
cxl_adapter_context_unlock(struct cxl * adapter)301 void cxl_adapter_context_unlock(struct cxl *adapter)
302 {
303 	int val = atomic_cmpxchg(&adapter->contexts_num, -1, 0);
304 
305 	/*
306 	 * contexts lock taken -> contexts_num == -1
307 	 * If not true then show a warning and force reset the lock.
308 	 * This will happen when context_unlock was requested without
309 	 * doing a context_lock.
310 	 */
311 	if (val != -1) {
312 		atomic_set(&adapter->contexts_num, 0);
313 		WARN(1, "Adapter context unlocked with %d active contexts",
314 		     val);
315 	}
316 }
317 
init_cxl(void)318 static int __init init_cxl(void)
319 {
320 	int rc = 0;
321 
322 	if ((rc = cxl_file_init()))
323 		return rc;
324 
325 	cxl_debugfs_init();
326 
327 	/*
328 	 * we don't register the callback on P9. slb callack is only
329 	 * used for the PSL8 MMU and CX4.
330 	 */
331 	if (cxl_is_power8()) {
332 		rc = register_cxl_calls(&cxl_calls);
333 		if (rc)
334 			goto err;
335 	}
336 
337 	if (cpu_has_feature(CPU_FTR_HVMODE)) {
338 		cxl_ops = &cxl_native_ops;
339 		rc = pci_register_driver(&cxl_pci_driver);
340 	}
341 #ifdef CONFIG_PPC_PSERIES
342 	else {
343 		cxl_ops = &cxl_guest_ops;
344 		rc = platform_driver_register(&cxl_of_driver);
345 	}
346 #endif
347 	if (rc)
348 		goto err1;
349 
350 	return 0;
351 err1:
352 	if (cxl_is_power8())
353 		unregister_cxl_calls(&cxl_calls);
354 err:
355 	cxl_debugfs_exit();
356 	cxl_file_exit();
357 
358 	return rc;
359 }
360 
exit_cxl(void)361 static void exit_cxl(void)
362 {
363 	if (cpu_has_feature(CPU_FTR_HVMODE))
364 		pci_unregister_driver(&cxl_pci_driver);
365 #ifdef CONFIG_PPC_PSERIES
366 	else
367 		platform_driver_unregister(&cxl_of_driver);
368 #endif
369 
370 	cxl_debugfs_exit();
371 	cxl_file_exit();
372 	if (cxl_is_power8())
373 		unregister_cxl_calls(&cxl_calls);
374 	idr_destroy(&cxl_adapter_idr);
375 }
376 
377 module_init(init_cxl);
378 module_exit(exit_cxl);
379 
380 MODULE_DESCRIPTION("IBM Coherent Accelerator");
381 MODULE_AUTHOR("Ian Munsie <imunsie@au1.ibm.com>");
382 MODULE_LICENSE("GPL");
383