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/kernel.h>
12#include <linux/bitmap.h>
13#include <linux/sched.h>
14#include <linux/pid.h>
15#include <linux/fs.h>
16#include <linux/mm.h>
17#include <linux/debugfs.h>
18#include <linux/slab.h>
19#include <linux/idr.h>
20#include <asm/cputable.h>
21#include <asm/current.h>
22#include <asm/copro.h>
23
24#include "cxl.h"
25
26/*
27 * Allocates space for a CXL context.
28 */
29struct cxl_context *cxl_context_alloc(void)
30{
31	return kzalloc(sizeof(struct cxl_context), GFP_KERNEL);
32}
33
34/*
35 * Initialises a CXL context.
36 */
37int cxl_context_init(struct cxl_context *ctx, struct cxl_afu *afu, bool master)
38{
39	int i;
40
41	spin_lock_init(&ctx->sste_lock);
42	ctx->afu = afu;
43	ctx->master = master;
44	ctx->pid = NULL; /* Set in start work ioctl */
45
46	/*
47	 * Allocate the segment table before we put it in the IDR so that we
48	 * can always access it when dereferenced from IDR. For the same
49	 * reason, the segment table is only destroyed after the context is
50	 * removed from the IDR.  Access to this in the IOCTL is protected by
51	 * Linux filesytem symantics (can't IOCTL until open is complete).
52	 */
53	i = cxl_alloc_sst(ctx);
54	if (i)
55		return i;
56
57	INIT_WORK(&ctx->fault_work, cxl_handle_fault);
58
59	init_waitqueue_head(&ctx->wq);
60	spin_lock_init(&ctx->lock);
61
62	ctx->irq_bitmap = NULL;
63	ctx->pending_irq = false;
64	ctx->pending_fault = false;
65	ctx->pending_afu_err = false;
66
67	/*
68	 * When we have to destroy all contexts in cxl_context_detach_all() we
69	 * end up with afu_release_irqs() called from inside a
70	 * idr_for_each_entry(). Hence we need to make sure that anything
71	 * dereferenced from this IDR is ok before we allocate the IDR here.
72	 * This clears out the IRQ ranges to ensure this.
73	 */
74	for (i = 0; i < CXL_IRQ_RANGES; i++)
75		ctx->irqs.range[i] = 0;
76
77	mutex_init(&ctx->status_mutex);
78
79	ctx->status = OPENED;
80
81	/*
82	 * Allocating IDR! We better make sure everything's setup that
83	 * dereferences from it.
84	 */
85	idr_preload(GFP_KERNEL);
86	spin_lock(&afu->contexts_lock);
87	i = idr_alloc(&ctx->afu->contexts_idr, ctx, 0,
88		      ctx->afu->num_procs, GFP_NOWAIT);
89	spin_unlock(&afu->contexts_lock);
90	idr_preload_end();
91	if (i < 0)
92		return i;
93
94	ctx->pe = i;
95	ctx->elem = &ctx->afu->spa[i];
96	ctx->pe_inserted = false;
97	return 0;
98}
99
100/*
101 * Map a per-context mmio space into the given vma.
102 */
103int cxl_context_iomap(struct cxl_context *ctx, struct vm_area_struct *vma)
104{
105	u64 len = vma->vm_end - vma->vm_start;
106	len = min(len, ctx->psn_size);
107
108	if (ctx->afu->current_mode == CXL_MODE_DEDICATED) {
109		vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);
110		return vm_iomap_memory(vma, ctx->afu->psn_phys, ctx->afu->adapter->ps_size);
111	}
112
113	/* make sure there is a valid per process space for this AFU */
114	if ((ctx->master && !ctx->afu->psa) || (!ctx->afu->pp_psa)) {
115		pr_devel("AFU doesn't support mmio space\n");
116		return -EINVAL;
117	}
118
119	/* Can't mmap until the AFU is enabled */
120	if (!ctx->afu->enabled)
121		return -EBUSY;
122
123	pr_devel("%s: mmio physical: %llx pe: %i master:%i\n", __func__,
124		 ctx->psn_phys, ctx->pe , ctx->master);
125
126	vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);
127	return vm_iomap_memory(vma, ctx->psn_phys, len);
128}
129
130/*
131 * Detach a context from the hardware. This disables interrupts and doesn't
132 * return until all outstanding interrupts for this context have completed. The
133 * hardware should no longer access *ctx after this has returned.
134 */
135static void __detach_context(struct cxl_context *ctx)
136{
137	enum cxl_context_status status;
138
139	mutex_lock(&ctx->status_mutex);
140	status = ctx->status;
141	ctx->status = CLOSED;
142	mutex_unlock(&ctx->status_mutex);
143	if (status != STARTED)
144		return;
145
146	WARN_ON(cxl_detach_process(ctx));
147	afu_release_irqs(ctx);
148	flush_work(&ctx->fault_work); /* Only needed for dedicated process */
149	wake_up_all(&ctx->wq);
150}
151
152/*
153 * Detach the given context from the AFU. This doesn't actually
154 * free the context but it should stop the context running in hardware
155 * (ie. prevent this context from generating any further interrupts
156 * so that it can be freed).
157 */
158void cxl_context_detach(struct cxl_context *ctx)
159{
160	__detach_context(ctx);
161}
162
163/*
164 * Detach all contexts on the given AFU.
165 */
166void cxl_context_detach_all(struct cxl_afu *afu)
167{
168	struct cxl_context *ctx;
169	int tmp;
170
171	rcu_read_lock();
172	idr_for_each_entry(&afu->contexts_idr, ctx, tmp)
173		/*
174		 * Anything done in here needs to be setup before the IDR is
175		 * created and torn down after the IDR removed
176		 */
177		__detach_context(ctx);
178	rcu_read_unlock();
179}
180
181void cxl_context_free(struct cxl_context *ctx)
182{
183	spin_lock(&ctx->afu->contexts_lock);
184	idr_remove(&ctx->afu->contexts_idr, ctx->pe);
185	spin_unlock(&ctx->afu->contexts_lock);
186	synchronize_rcu();
187
188	free_page((u64)ctx->sstp);
189	ctx->sstp = NULL;
190
191	put_pid(ctx->pid);
192	kfree(ctx);
193}
194