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 <asm/cputable.h>
 23#include <misc/cxl-base.h>
 24
 25#include "cxl.h"
 26#include "trace.h"
 27
 28static DEFINE_SPINLOCK(adapter_idr_lock);
 29static DEFINE_IDR(cxl_adapter_idr);
 30
 31uint cxl_verbose;
 32module_param_named(verbose, cxl_verbose, uint, 0600);
 33MODULE_PARM_DESC(verbose, "Enable verbose dmesg output");
 34
 35const struct cxl_backend_ops *cxl_ops;
 36
 37int cxl_afu_slbia(struct cxl_afu *afu)
 38{
 39	unsigned long timeout = jiffies + (HZ * CXL_TIMEOUT);
 40
 41	pr_devel("cxl_afu_slbia issuing SLBIA command\n");
 42	cxl_p2n_write(afu, CXL_SLBIA_An, CXL_TLB_SLB_IQ_ALL);
 43	while (cxl_p2n_read(afu, CXL_SLBIA_An) & CXL_TLB_SLB_P) {
 44		if (time_after_eq(jiffies, timeout)) {
 45			dev_warn(&afu->dev, "WARNING: CXL AFU SLBIA timed out!\n");
 46			return -EBUSY;
 47		}
 48		/* If the adapter has gone down, we can assume that we
 49		 * will PERST it and that will invalidate everything.
 50		 */
 51		if (!cxl_ops->link_ok(afu->adapter, afu))
 52			return -EIO;
 53		cpu_relax();
 54	}
 55	return 0;
 56}
 57
 58static inline void _cxl_slbia(struct cxl_context *ctx, struct mm_struct *mm)
 59{
 60	struct task_struct *task;
 61	unsigned long flags;
 62	if (!(task = get_pid_task(ctx->pid, PIDTYPE_PID))) {
 63		pr_devel("%s unable to get task %i\n",
 64			 __func__, pid_nr(ctx->pid));
 65		return;
 66	}
 67
 68	if (task->mm != mm)
 69		goto out_put;
 70
 71	pr_devel("%s matched mm - card: %i afu: %i pe: %i\n", __func__,
 72		 ctx->afu->adapter->adapter_num, ctx->afu->slice, ctx->pe);
 73
 74	spin_lock_irqsave(&ctx->sste_lock, flags);
 75	trace_cxl_slbia(ctx);
 76	memset(ctx->sstp, 0, ctx->sst_size);
 77	spin_unlock_irqrestore(&ctx->sste_lock, flags);
 78	mb();
 79	cxl_afu_slbia(ctx->afu);
 80out_put:
 81	put_task_struct(task);
 82}
 83
 84static inline void cxl_slbia_core(struct mm_struct *mm)
 85{
 86	struct cxl *adapter;
 87	struct cxl_afu *afu;
 88	struct cxl_context *ctx;
 89	int card, slice, id;
 90
 91	pr_devel("%s called\n", __func__);
 92
 93	spin_lock(&adapter_idr_lock);
 94	idr_for_each_entry(&cxl_adapter_idr, adapter, card) {
 95		/* XXX: Make this lookup faster with link from mm to ctx */
 96		spin_lock(&adapter->afu_list_lock);
 97		for (slice = 0; slice < adapter->slices; slice++) {
 98			afu = adapter->afu[slice];
 99			if (!afu || !afu->enabled)
100				continue;
101			rcu_read_lock();
102			idr_for_each_entry(&afu->contexts_idr, ctx, id)
103				_cxl_slbia(ctx, mm);
104			rcu_read_unlock();
105		}
106		spin_unlock(&adapter->afu_list_lock);
107	}
108	spin_unlock(&adapter_idr_lock);
109}
110
111static struct cxl_calls cxl_calls = {
112	.cxl_slbia = cxl_slbia_core,
113	.cxl_pci_associate_default_context = _cxl_pci_associate_default_context,
114	.cxl_pci_disable_device = _cxl_pci_disable_device,
115	.cxl_next_msi_hwirq = _cxl_next_msi_hwirq,
116	.cxl_cx4_setup_msi_irqs = _cxl_cx4_setup_msi_irqs,
117	.cxl_cx4_teardown_msi_irqs = _cxl_cx4_teardown_msi_irqs,
118	.owner = THIS_MODULE,
119};
120
121int cxl_alloc_sst(struct cxl_context *ctx)
122{
123	unsigned long vsid;
124	u64 ea_mask, size, sstp0, sstp1;
125
126	sstp0 = 0;
127	sstp1 = 0;
128
129	ctx->sst_size = PAGE_SIZE;
130	ctx->sst_lru = 0;
131	ctx->sstp = (struct cxl_sste *)get_zeroed_page(GFP_KERNEL);
132	if (!ctx->sstp) {
133		pr_err("cxl_alloc_sst: Unable to allocate segment table\n");
134		return -ENOMEM;
135	}
136	pr_devel("SSTP allocated at 0x%p\n", ctx->sstp);
137
138	vsid  = get_kernel_vsid((u64)ctx->sstp, mmu_kernel_ssize) << 12;
139
140	sstp0 |= (u64)mmu_kernel_ssize << CXL_SSTP0_An_B_SHIFT;
141	sstp0 |= (SLB_VSID_KERNEL | mmu_psize_defs[mmu_linear_psize].sllp) << 50;
142
143	size = (((u64)ctx->sst_size >> 8) - 1) << CXL_SSTP0_An_SegTableSize_SHIFT;
144	if (unlikely(size & ~CXL_SSTP0_An_SegTableSize_MASK)) {
145		WARN(1, "Impossible segment table size\n");
146		return -EINVAL;
147	}
148	sstp0 |= size;
149
150	if (mmu_kernel_ssize == MMU_SEGSIZE_256M)
151		ea_mask = 0xfffff00ULL;
152	else
153		ea_mask = 0xffffffff00ULL;
154
155	sstp0 |=  vsid >>     (50-14);  /*   Top 14 bits of VSID */
156	sstp1 |= (vsid << (64-(50-14))) & ~ea_mask;
157	sstp1 |= (u64)ctx->sstp & ea_mask;
158	sstp1 |= CXL_SSTP1_An_V;
159
160	pr_devel("Looked up %#llx: slbfee. %#llx (ssize: %x, vsid: %#lx), copied to SSTP0: %#llx, SSTP1: %#llx\n",
161			(u64)ctx->sstp, (u64)ctx->sstp & ESID_MASK, mmu_kernel_ssize, vsid, sstp0, sstp1);
162
163	/* Store calculated sstp hardware points for use later */
164	ctx->sstp0 = sstp0;
165	ctx->sstp1 = sstp1;
166
167	return 0;
168}
169
170/* print buffer content as integers when debugging */
171void cxl_dump_debug_buffer(void *buf, size_t buf_len)
172{
173#ifdef DEBUG
174	int i, *ptr;
175
176	/*
177	 * We want to regroup up to 4 integers per line, which means they
178	 * need to be in the same pr_devel() statement
179	 */
180	ptr = (int *) buf;
181	for (i = 0; i * 4 < buf_len; i += 4) {
182		if ((i + 3) * 4 < buf_len)
183			pr_devel("%.8x %.8x %.8x %.8x\n", ptr[i], ptr[i + 1],
184				ptr[i + 2], ptr[i + 3]);
185		else if ((i + 2) * 4 < buf_len)
186			pr_devel("%.8x %.8x %.8x\n", ptr[i], ptr[i + 1],
187				ptr[i + 2]);
188		else if ((i + 1) * 4 < buf_len)
189			pr_devel("%.8x %.8x\n", ptr[i], ptr[i + 1]);
190		else
191			pr_devel("%.8x\n", ptr[i]);
192	}
193#endif /* DEBUG */
194}
195
196/* Find a CXL adapter by it's number and increase it's refcount */
197struct cxl *get_cxl_adapter(int num)
198{
199	struct cxl *adapter;
200
201	spin_lock(&adapter_idr_lock);
202	if ((adapter = idr_find(&cxl_adapter_idr, num)))
203		get_device(&adapter->dev);
204	spin_unlock(&adapter_idr_lock);
205
206	return adapter;
207}
208
209static int cxl_alloc_adapter_nr(struct cxl *adapter)
210{
211	int i;
212
213	idr_preload(GFP_KERNEL);
214	spin_lock(&adapter_idr_lock);
215	i = idr_alloc(&cxl_adapter_idr, adapter, 0, 0, GFP_NOWAIT);
216	spin_unlock(&adapter_idr_lock);
217	idr_preload_end();
218	if (i < 0)
219		return i;
220
221	adapter->adapter_num = i;
222
223	return 0;
224}
225
226void cxl_remove_adapter_nr(struct cxl *adapter)
227{
228	idr_remove(&cxl_adapter_idr, adapter->adapter_num);
229}
230
231struct cxl *cxl_alloc_adapter(void)
232{
233	struct cxl *adapter;
234
235	if (!(adapter = kzalloc(sizeof(struct cxl), GFP_KERNEL)))
236		return NULL;
237
238	spin_lock_init(&adapter->afu_list_lock);
239
240	if (cxl_alloc_adapter_nr(adapter))
241		goto err1;
242
243	if (dev_set_name(&adapter->dev, "card%i", adapter->adapter_num))
244		goto err2;
245
246	/* start with context lock taken */
247	atomic_set(&adapter->contexts_num, -1);
248
249	return adapter;
250err2:
251	cxl_remove_adapter_nr(adapter);
252err1:
253	kfree(adapter);
254	return NULL;
255}
256
257struct cxl_afu *cxl_alloc_afu(struct cxl *adapter, int slice)
258{
259	struct cxl_afu *afu;
260
261	if (!(afu = kzalloc(sizeof(struct cxl_afu), GFP_KERNEL)))
262		return NULL;
263
264	afu->adapter = adapter;
265	afu->dev.parent = &adapter->dev;
266	afu->dev.release = cxl_ops->release_afu;
267	afu->slice = slice;
268	idr_init(&afu->contexts_idr);
269	mutex_init(&afu->contexts_lock);
270	spin_lock_init(&afu->afu_cntl_lock);
271	atomic_set(&afu->configured_state, -1);
272	afu->prefault_mode = CXL_PREFAULT_NONE;
273	afu->irqs_max = afu->adapter->user_irqs;
274
275	return afu;
276}
277
278int cxl_afu_select_best_mode(struct cxl_afu *afu)
279{
280	if (afu->modes_supported & CXL_MODE_DIRECTED)
281		return cxl_ops->afu_activate_mode(afu, CXL_MODE_DIRECTED);
282
283	if (afu->modes_supported & CXL_MODE_DEDICATED)
284		return cxl_ops->afu_activate_mode(afu, CXL_MODE_DEDICATED);
285
286	dev_warn(&afu->dev, "No supported programming modes available\n");
287	/* We don't fail this so the user can inspect sysfs */
288	return 0;
289}
290
291int cxl_adapter_context_get(struct cxl *adapter)
292{
293	int rc;
294
295	rc = atomic_inc_unless_negative(&adapter->contexts_num);
296	return rc >= 0 ? 0 : -EBUSY;
297}
298
299void cxl_adapter_context_put(struct cxl *adapter)
300{
301	atomic_dec_if_positive(&adapter->contexts_num);
302}
303
304int cxl_adapter_context_lock(struct cxl *adapter)
305{
306	int rc;
307	/* no active contexts -> contexts_num == 0 */
308	rc = atomic_cmpxchg(&adapter->contexts_num, 0, -1);
309	return rc ? -EBUSY : 0;
310}
311
312void cxl_adapter_context_unlock(struct cxl *adapter)
313{
314	int val = atomic_cmpxchg(&adapter->contexts_num, -1, 0);
315
316	/*
317	 * contexts lock taken -> contexts_num == -1
318	 * If not true then show a warning and force reset the lock.
319	 * This will happen when context_unlock was requested without
320	 * doing a context_lock.
321	 */
322	if (val != -1) {
323		atomic_set(&adapter->contexts_num, 0);
324		WARN(1, "Adapter context unlocked with %d active contexts",
325		     val);
326	}
327}
328
329static int __init init_cxl(void)
330{
331	int rc = 0;
332
333	if ((rc = cxl_file_init()))
334		return rc;
335
336	cxl_debugfs_init();
337
338	if ((rc = register_cxl_calls(&cxl_calls)))
339		goto err;
340
341	if (cpu_has_feature(CPU_FTR_HVMODE)) {
342		cxl_ops = &cxl_native_ops;
343		rc = pci_register_driver(&cxl_pci_driver);
344	}
345#ifdef CONFIG_PPC_PSERIES
346	else {
347		cxl_ops = &cxl_guest_ops;
348		rc = platform_driver_register(&cxl_of_driver);
349	}
350#endif
351	if (rc)
352		goto err1;
353
354	return 0;
355err1:
356	unregister_cxl_calls(&cxl_calls);
357err:
358	cxl_debugfs_exit();
359	cxl_file_exit();
360
361	return rc;
362}
363
364static void exit_cxl(void)
365{
366	if (cpu_has_feature(CPU_FTR_HVMODE))
367		pci_unregister_driver(&cxl_pci_driver);
368#ifdef CONFIG_PPC_PSERIES
369	else
370		platform_driver_unregister(&cxl_of_driver);
371#endif
372
373	cxl_debugfs_exit();
374	cxl_file_exit();
375	unregister_cxl_calls(&cxl_calls);
376	idr_destroy(&cxl_adapter_idr);
377}
378
379module_init(init_cxl);
380module_exit(exit_cxl);
381
382MODULE_DESCRIPTION("IBM Coherent Accelerator");
383MODULE_AUTHOR("Ian Munsie <imunsie@au1.ibm.com>");
384MODULE_LICENSE("GPL");