xref: /openbmc/linux/drivers/misc/cxl/main.c (revision a8da474e)
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 
28 static DEFINE_SPINLOCK(adapter_idr_lock);
29 static DEFINE_IDR(cxl_adapter_idr);
30 
31 uint cxl_verbose;
32 module_param_named(verbose, cxl_verbose, uint, 0600);
33 MODULE_PARM_DESC(verbose, "Enable verbose dmesg output");
34 
35 static inline void _cxl_slbia(struct cxl_context *ctx, struct mm_struct *mm)
36 {
37 	struct task_struct *task;
38 	unsigned long flags;
39 	if (!(task = get_pid_task(ctx->pid, PIDTYPE_PID))) {
40 		pr_devel("%s unable to get task %i\n",
41 			 __func__, pid_nr(ctx->pid));
42 		return;
43 	}
44 
45 	if (task->mm != mm)
46 		goto out_put;
47 
48 	pr_devel("%s matched mm - card: %i afu: %i pe: %i\n", __func__,
49 		 ctx->afu->adapter->adapter_num, ctx->afu->slice, ctx->pe);
50 
51 	spin_lock_irqsave(&ctx->sste_lock, flags);
52 	trace_cxl_slbia(ctx);
53 	memset(ctx->sstp, 0, ctx->sst_size);
54 	spin_unlock_irqrestore(&ctx->sste_lock, flags);
55 	mb();
56 	cxl_afu_slbia(ctx->afu);
57 out_put:
58 	put_task_struct(task);
59 }
60 
61 static inline void cxl_slbia_core(struct mm_struct *mm)
62 {
63 	struct cxl *adapter;
64 	struct cxl_afu *afu;
65 	struct cxl_context *ctx;
66 	int card, slice, id;
67 
68 	pr_devel("%s called\n", __func__);
69 
70 	spin_lock(&adapter_idr_lock);
71 	idr_for_each_entry(&cxl_adapter_idr, adapter, card) {
72 		/* XXX: Make this lookup faster with link from mm to ctx */
73 		spin_lock(&adapter->afu_list_lock);
74 		for (slice = 0; slice < adapter->slices; slice++) {
75 			afu = adapter->afu[slice];
76 			if (!afu || !afu->enabled)
77 				continue;
78 			rcu_read_lock();
79 			idr_for_each_entry(&afu->contexts_idr, ctx, id)
80 				_cxl_slbia(ctx, mm);
81 			rcu_read_unlock();
82 		}
83 		spin_unlock(&adapter->afu_list_lock);
84 	}
85 	spin_unlock(&adapter_idr_lock);
86 }
87 
88 static struct cxl_calls cxl_calls = {
89 	.cxl_slbia = cxl_slbia_core,
90 	.owner = THIS_MODULE,
91 };
92 
93 int cxl_alloc_sst(struct cxl_context *ctx)
94 {
95 	unsigned long vsid;
96 	u64 ea_mask, size, sstp0, sstp1;
97 
98 	sstp0 = 0;
99 	sstp1 = 0;
100 
101 	ctx->sst_size = PAGE_SIZE;
102 	ctx->sst_lru = 0;
103 	ctx->sstp = (struct cxl_sste *)get_zeroed_page(GFP_KERNEL);
104 	if (!ctx->sstp) {
105 		pr_err("cxl_alloc_sst: Unable to allocate segment table\n");
106 		return -ENOMEM;
107 	}
108 	pr_devel("SSTP allocated at 0x%p\n", ctx->sstp);
109 
110 	vsid  = get_kernel_vsid((u64)ctx->sstp, mmu_kernel_ssize) << 12;
111 
112 	sstp0 |= (u64)mmu_kernel_ssize << CXL_SSTP0_An_B_SHIFT;
113 	sstp0 |= (SLB_VSID_KERNEL | mmu_psize_defs[mmu_linear_psize].sllp) << 50;
114 
115 	size = (((u64)ctx->sst_size >> 8) - 1) << CXL_SSTP0_An_SegTableSize_SHIFT;
116 	if (unlikely(size & ~CXL_SSTP0_An_SegTableSize_MASK)) {
117 		WARN(1, "Impossible segment table size\n");
118 		return -EINVAL;
119 	}
120 	sstp0 |= size;
121 
122 	if (mmu_kernel_ssize == MMU_SEGSIZE_256M)
123 		ea_mask = 0xfffff00ULL;
124 	else
125 		ea_mask = 0xffffffff00ULL;
126 
127 	sstp0 |=  vsid >>     (50-14);  /*   Top 14 bits of VSID */
128 	sstp1 |= (vsid << (64-(50-14))) & ~ea_mask;
129 	sstp1 |= (u64)ctx->sstp & ea_mask;
130 	sstp1 |= CXL_SSTP1_An_V;
131 
132 	pr_devel("Looked up %#llx: slbfee. %#llx (ssize: %x, vsid: %#lx), copied to SSTP0: %#llx, SSTP1: %#llx\n",
133 			(u64)ctx->sstp, (u64)ctx->sstp & ESID_MASK, mmu_kernel_ssize, vsid, sstp0, sstp1);
134 
135 	/* Store calculated sstp hardware points for use later */
136 	ctx->sstp0 = sstp0;
137 	ctx->sstp1 = sstp1;
138 
139 	return 0;
140 }
141 
142 /* Find a CXL adapter by it's number and increase it's refcount */
143 struct cxl *get_cxl_adapter(int num)
144 {
145 	struct cxl *adapter;
146 
147 	spin_lock(&adapter_idr_lock);
148 	if ((adapter = idr_find(&cxl_adapter_idr, num)))
149 		get_device(&adapter->dev);
150 	spin_unlock(&adapter_idr_lock);
151 
152 	return adapter;
153 }
154 
155 int cxl_alloc_adapter_nr(struct cxl *adapter)
156 {
157 	int i;
158 
159 	idr_preload(GFP_KERNEL);
160 	spin_lock(&adapter_idr_lock);
161 	i = idr_alloc(&cxl_adapter_idr, adapter, 0, 0, GFP_NOWAIT);
162 	spin_unlock(&adapter_idr_lock);
163 	idr_preload_end();
164 	if (i < 0)
165 		return i;
166 
167 	adapter->adapter_num = i;
168 
169 	return 0;
170 }
171 
172 void cxl_remove_adapter_nr(struct cxl *adapter)
173 {
174 	idr_remove(&cxl_adapter_idr, adapter->adapter_num);
175 }
176 
177 int cxl_afu_select_best_mode(struct cxl_afu *afu)
178 {
179 	if (afu->modes_supported & CXL_MODE_DIRECTED)
180 		return cxl_afu_activate_mode(afu, CXL_MODE_DIRECTED);
181 
182 	if (afu->modes_supported & CXL_MODE_DEDICATED)
183 		return cxl_afu_activate_mode(afu, CXL_MODE_DEDICATED);
184 
185 	dev_warn(&afu->dev, "No supported programming modes available\n");
186 	/* We don't fail this so the user can inspect sysfs */
187 	return 0;
188 }
189 
190 static int __init init_cxl(void)
191 {
192 	int rc = 0;
193 
194 	if (!cpu_has_feature(CPU_FTR_HVMODE))
195 		return -EPERM;
196 
197 	if ((rc = cxl_file_init()))
198 		return rc;
199 
200 	cxl_debugfs_init();
201 
202 	if ((rc = register_cxl_calls(&cxl_calls)))
203 		goto err;
204 
205 	if ((rc = pci_register_driver(&cxl_pci_driver)))
206 		goto err1;
207 
208 	return 0;
209 err1:
210 	unregister_cxl_calls(&cxl_calls);
211 err:
212 	cxl_debugfs_exit();
213 	cxl_file_exit();
214 
215 	return rc;
216 }
217 
218 static void exit_cxl(void)
219 {
220 	pci_unregister_driver(&cxl_pci_driver);
221 
222 	cxl_debugfs_exit();
223 	cxl_file_exit();
224 	unregister_cxl_calls(&cxl_calls);
225 	idr_destroy(&cxl_adapter_idr);
226 }
227 
228 module_init(init_cxl);
229 module_exit(exit_cxl);
230 
231 MODULE_DESCRIPTION("IBM Coherent Accelerator");
232 MODULE_AUTHOR("Ian Munsie <imunsie@au1.ibm.com>");
233 MODULE_LICENSE("GPL");
234