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/module.h>
 11#include <linux/rcupdate.h>
 12#include <asm/errno.h>
 13#include <misc/cxl-base.h>
 14#include <linux/of_platform.h>
 15#include "cxl.h"
 16
 17/* protected by rcu */
 18static struct cxl_calls *cxl_calls;
 19
 20atomic_t cxl_use_count = ATOMIC_INIT(0);
 21EXPORT_SYMBOL(cxl_use_count);
 22
 23#ifdef CONFIG_CXL_MODULE
 24
 25static inline struct cxl_calls *cxl_calls_get(void)
 26{
 27	struct cxl_calls *calls = NULL;
 28
 29	rcu_read_lock();
 30	calls = rcu_dereference(cxl_calls);
 31	if (calls && !try_module_get(calls->owner))
 32		calls = NULL;
 33	rcu_read_unlock();
 34
 35	return calls;
 36}
 37
 38static inline void cxl_calls_put(struct cxl_calls *calls)
 39{
 40	BUG_ON(calls != cxl_calls);
 41
 42	/* we don't need to rcu this, as we hold a reference to the module */
 43	module_put(cxl_calls->owner);
 44}
 45
 46#else /* !defined CONFIG_CXL_MODULE */
 47
 48static inline struct cxl_calls *cxl_calls_get(void)
 49{
 50	return cxl_calls;
 51}
 52
 53static inline void cxl_calls_put(struct cxl_calls *calls) { }
 54
 55#endif /* CONFIG_CXL_MODULE */
 56
 57/* AFU refcount management */
 58struct cxl_afu *cxl_afu_get(struct cxl_afu *afu)
 59{
 60	return (get_device(&afu->dev) == NULL) ? NULL : afu;
 61}
 62EXPORT_SYMBOL_GPL(cxl_afu_get);
 63
 64void cxl_afu_put(struct cxl_afu *afu)
 65{
 66	put_device(&afu->dev);
 67}
 68EXPORT_SYMBOL_GPL(cxl_afu_put);
 69
 70void cxl_slbia(struct mm_struct *mm)
 71{
 72	struct cxl_calls *calls;
 73
 74	calls = cxl_calls_get();
 75	if (!calls)
 76		return;
 77
 78	if (cxl_ctx_in_use())
 79	    calls->cxl_slbia(mm);
 80
 81	cxl_calls_put(calls);
 82}
 83
 84int register_cxl_calls(struct cxl_calls *calls)
 85{
 86	if (cxl_calls)
 87		return -EBUSY;
 88
 89	rcu_assign_pointer(cxl_calls, calls);
 90	return 0;
 91}
 92EXPORT_SYMBOL_GPL(register_cxl_calls);
 93
 94void unregister_cxl_calls(struct cxl_calls *calls)
 95{
 96	BUG_ON(cxl_calls->owner != calls->owner);
 97	RCU_INIT_POINTER(cxl_calls, NULL);
 98	synchronize_rcu();
 99}
100EXPORT_SYMBOL_GPL(unregister_cxl_calls);
101
102int cxl_update_properties(struct device_node *dn,
103			  struct property *new_prop)
104{
105	return of_update_property(dn, new_prop);
106}
107EXPORT_SYMBOL_GPL(cxl_update_properties);
108
109/*
110 * API calls into the driver that may be called from the PHB code and must be
111 * built in.
112 */
113bool cxl_pci_associate_default_context(struct pci_dev *dev, struct cxl_afu *afu)
114{
115	bool ret;
116	struct cxl_calls *calls;
117
118	calls = cxl_calls_get();
119	if (!calls)
120		return false;
121
122	ret = calls->cxl_pci_associate_default_context(dev, afu);
123
124	cxl_calls_put(calls);
125
126	return ret;
127}
128EXPORT_SYMBOL_GPL(cxl_pci_associate_default_context);
129
130void cxl_pci_disable_device(struct pci_dev *dev)
131{
132	struct cxl_calls *calls;
133
134	calls = cxl_calls_get();
135	if (!calls)
136		return;
137
138	calls->cxl_pci_disable_device(dev);
139
140	cxl_calls_put(calls);
141}
142EXPORT_SYMBOL_GPL(cxl_pci_disable_device);
143
144int cxl_next_msi_hwirq(struct pci_dev *pdev, struct cxl_context **ctx, int *afu_irq)
145{
146	int ret;
147	struct cxl_calls *calls;
148
149	calls = cxl_calls_get();
150	if (!calls)
151		return -EBUSY;
152
153	ret = calls->cxl_next_msi_hwirq(pdev, ctx, afu_irq);
154
155	cxl_calls_put(calls);
156
157	return ret;
158}
159EXPORT_SYMBOL_GPL(cxl_next_msi_hwirq);
160
161int cxl_cx4_setup_msi_irqs(struct pci_dev *pdev, int nvec, int type)
162{
163	int ret;
164	struct cxl_calls *calls;
165
166	calls = cxl_calls_get();
167	if (!calls)
168		return false;
169
170	ret = calls->cxl_cx4_setup_msi_irqs(pdev, nvec, type);
171
172	cxl_calls_put(calls);
173
174	return ret;
175}
176EXPORT_SYMBOL_GPL(cxl_cx4_setup_msi_irqs);
177
178void cxl_cx4_teardown_msi_irqs(struct pci_dev *pdev)
179{
180	struct cxl_calls *calls;
181
182	calls = cxl_calls_get();
183	if (!calls)
184		return;
185
186	calls->cxl_cx4_teardown_msi_irqs(pdev);
187
188	cxl_calls_put(calls);
189}
190EXPORT_SYMBOL_GPL(cxl_cx4_teardown_msi_irqs);
191
192static int __init cxl_base_init(void)
193{
194	struct device_node *np;
195	struct platform_device *dev;
196	int count = 0;
197
198	/*
199	 * Scan for compatible devices in guest only
200	 */
201	if (cpu_has_feature(CPU_FTR_HVMODE))
202		return 0;
203
204	for_each_compatible_node(np, NULL, "ibm,coherent-platform-facility") {
205		dev = of_platform_device_create(np, NULL, NULL);
206		if (dev)
207			count++;
208	}
209	pr_devel("Found %d cxl device(s)\n", count);
210	return 0;
211}
212device_initcall(cxl_base_init);