1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * AMD Platform Security Processor (PSP) interface
4 *
5 * Copyright (C) 2016,2019 Advanced Micro Devices, Inc.
6 *
7 * Author: Brijesh Singh <brijesh.singh@amd.com>
8 */
9
10#include <linux/kernel.h>
11#include <linux/irqreturn.h>
12#include <linux/mutex.h>
13#include <linux/bitfield.h>
14#include <linux/delay.h>
15
16#include "sp-dev.h"
17#include "psp-dev.h"
18#include "sev-dev.h"
19#include "tee-dev.h"
20#include "platform-access.h"
21#include "dbc.h"
22#include "hsti.h"
23
24struct psp_device *psp_master;
25
26#define PSP_C2PMSG_17_CMDRESP_CMD GENMASK(19, 16)
27
28static int psp_mailbox_poll(const void __iomem *cmdresp_reg, unsigned int *cmdresp,
29 unsigned int timeout_msecs)
30{
31 while (true) {
32 *cmdresp = ioread32(cmdresp_reg);
33 if (FIELD_GET(PSP_CMDRESP_RESP, *cmdresp))
34 return 0;
35
36 if (!timeout_msecs--)
37 break;
38
39 usleep_range(min: 1000, max: 1100);
40 }
41
42 return -ETIMEDOUT;
43}
44
45int psp_mailbox_command(struct psp_device *psp, enum psp_cmd cmd, void *cmdbuff,
46 unsigned int timeout_msecs, unsigned int *cmdresp)
47{
48 void __iomem *cmdresp_reg, *cmdbuff_lo_reg, *cmdbuff_hi_reg;
49 int ret;
50
51 if (!psp || !psp->vdata || !psp->vdata->cmdresp_reg ||
52 !psp->vdata->cmdbuff_addr_lo_reg || !psp->vdata->cmdbuff_addr_hi_reg)
53 return -ENODEV;
54
55 cmdresp_reg = psp->io_regs + psp->vdata->cmdresp_reg;
56 cmdbuff_lo_reg = psp->io_regs + psp->vdata->cmdbuff_addr_lo_reg;
57 cmdbuff_hi_reg = psp->io_regs + psp->vdata->cmdbuff_addr_hi_reg;
58
59 mutex_lock(&psp->mailbox_mutex);
60
61 /* Ensure mailbox is ready for a command */
62 ret = -EBUSY;
63 if (psp_mailbox_poll(cmdresp_reg, cmdresp, timeout_msecs: 0))
64 goto unlock;
65
66 if (cmdbuff) {
67 iowrite32(lower_32_bits(__psp_pa(cmdbuff)), cmdbuff_lo_reg);
68 iowrite32(upper_32_bits(__psp_pa(cmdbuff)), cmdbuff_hi_reg);
69 }
70
71 *cmdresp = FIELD_PREP(PSP_C2PMSG_17_CMDRESP_CMD, cmd);
72 iowrite32(*cmdresp, cmdresp_reg);
73
74 ret = psp_mailbox_poll(cmdresp_reg, cmdresp, timeout_msecs);
75
76unlock:
77 mutex_unlock(lock: &psp->mailbox_mutex);
78
79 return ret;
80}
81
82int psp_extended_mailbox_cmd(struct psp_device *psp, unsigned int timeout_msecs,
83 struct psp_ext_request *req)
84{
85 unsigned int reg;
86 int ret;
87
88 print_hex_dump_debug("->psp ", DUMP_PREFIX_OFFSET, 16, 2, req,
89 req->header.payload_size, false);
90
91 ret = psp_mailbox_command(psp, cmd: PSP_CMD_TEE_EXTENDED_CMD, cmdbuff: (void *)req,
92 timeout_msecs, cmdresp: &reg);
93 if (ret) {
94 return ret;
95 } else if (FIELD_GET(PSP_CMDRESP_STS, reg)) {
96 req->header.status = FIELD_GET(PSP_CMDRESP_STS, reg);
97 return -EIO;
98 }
99
100 print_hex_dump_debug("<-psp ", DUMP_PREFIX_OFFSET, 16, 2, req,
101 req->header.payload_size, false);
102
103 return 0;
104}
105
106static struct psp_device *psp_alloc_struct(struct sp_device *sp)
107{
108 struct device *dev = sp->dev;
109 struct psp_device *psp;
110
111 psp = devm_kzalloc(dev, size: sizeof(*psp), GFP_KERNEL);
112 if (!psp)
113 return NULL;
114
115 psp->dev = dev;
116 psp->sp = sp;
117
118 snprintf(buf: psp->name, size: sizeof(psp->name), fmt: "psp-%u", sp->ord);
119
120 return psp;
121}
122
123static irqreturn_t psp_irq_handler(int irq, void *data)
124{
125 struct psp_device *psp = data;
126 unsigned int status;
127
128 /* Read the interrupt status: */
129 status = ioread32(psp->io_regs + psp->vdata->intsts_reg);
130
131 /* Clear the interrupt status by writing the same value we read. */
132 iowrite32(status, psp->io_regs + psp->vdata->intsts_reg);
133
134 /* invoke subdevice interrupt handlers */
135 if (status) {
136 if (psp->sev_irq_handler)
137 psp->sev_irq_handler(irq, psp->sev_irq_data, status);
138 }
139
140 return IRQ_HANDLED;
141}
142
143static unsigned int psp_get_capability(struct psp_device *psp)
144{
145 unsigned int val = ioread32(psp->io_regs + psp->vdata->feature_reg);
146
147 /*
148 * Check for a access to the registers. If this read returns
149 * 0xffffffff, it's likely that the system is running a broken
150 * BIOS which disallows access to the device. Stop here and
151 * fail the PSP initialization (but not the load, as the CCP
152 * could get properly initialized).
153 */
154 if (val == 0xffffffff) {
155 dev_notice(psp->dev, "psp: unable to access the device: you might be running a broken BIOS.\n");
156 return -ENODEV;
157 }
158 psp->capability.raw = val;
159
160 return 0;
161}
162
163static int psp_check_sev_support(struct psp_device *psp)
164{
165 /* Check if device supports SEV feature */
166 if (!psp->capability.sev) {
167 dev_dbg(psp->dev, "psp does not support SEV\n");
168 return -ENODEV;
169 }
170
171 return 0;
172}
173
174static int psp_check_tee_support(struct psp_device *psp)
175{
176 /* Check if device supports TEE feature */
177 if (!psp->capability.tee) {
178 dev_dbg(psp->dev, "psp does not support TEE\n");
179 return -ENODEV;
180 }
181
182 return 0;
183}
184
185static int psp_init(struct psp_device *psp)
186{
187 int ret;
188
189 if (!psp_check_sev_support(psp)) {
190 ret = sev_dev_init(psp);
191 if (ret)
192 return ret;
193 }
194
195 if (!psp_check_tee_support(psp)) {
196 ret = tee_dev_init(psp);
197 if (ret)
198 return ret;
199 }
200
201 if (psp->vdata->platform_access) {
202 ret = platform_access_dev_init(psp);
203 if (ret)
204 return ret;
205 }
206
207 /* dbc must come after platform access as it tests the feature */
208 if (PSP_FEATURE(psp, DBC) ||
209 psp->capability.dbc_thru_ext) {
210 ret = dbc_dev_init(psp);
211 if (ret)
212 return ret;
213 }
214
215 /* HSTI uses platform access on some systems. */
216 ret = psp_init_hsti(psp);
217 if (ret)
218 return ret;
219
220 return 0;
221}
222
223int psp_dev_init(struct sp_device *sp)
224{
225 struct device *dev = sp->dev;
226 struct psp_device *psp;
227 int ret;
228
229 ret = -ENOMEM;
230 psp = psp_alloc_struct(sp);
231 if (!psp)
232 goto e_err;
233
234 sp->psp_data = psp;
235
236 psp->vdata = (struct psp_vdata *)sp->dev_vdata->psp_vdata;
237 if (!psp->vdata) {
238 ret = -ENODEV;
239 dev_err(dev, "missing driver data\n");
240 goto e_err;
241 }
242
243 psp->io_regs = sp->io_map;
244 mutex_init(&psp->mailbox_mutex);
245
246 ret = psp_get_capability(psp);
247 if (ret)
248 goto e_disable;
249
250 /* Disable and clear interrupts until ready */
251 iowrite32(0, psp->io_regs + psp->vdata->inten_reg);
252 iowrite32(-1, psp->io_regs + psp->vdata->intsts_reg);
253
254 /* Request an irq */
255 ret = sp_request_psp_irq(sp: psp->sp, handler: psp_irq_handler, name: psp->name, data: psp);
256 if (ret) {
257 dev_err(dev, "psp: unable to allocate an IRQ\n");
258 goto e_err;
259 }
260
261 /* master device must be set for platform access */
262 if (psp->sp->set_psp_master_device)
263 psp->sp->set_psp_master_device(psp->sp);
264
265 ret = psp_init(psp);
266 if (ret)
267 goto e_irq;
268
269 /* Enable interrupt */
270 iowrite32(-1, psp->io_regs + psp->vdata->inten_reg);
271
272 dev_notice(dev, "psp enabled\n");
273
274 return 0;
275
276e_irq:
277 if (sp->clear_psp_master_device)
278 sp->clear_psp_master_device(sp);
279
280 sp_free_psp_irq(sp: psp->sp, data: psp);
281e_err:
282 sp->psp_data = NULL;
283
284 dev_notice(dev, "psp initialization failed\n");
285
286 return ret;
287
288e_disable:
289 sp->psp_data = NULL;
290
291 return ret;
292}
293
294void psp_dev_destroy(struct sp_device *sp)
295{
296 struct psp_device *psp = sp->psp_data;
297
298 if (!psp)
299 return;
300
301 sev_dev_destroy(psp);
302
303 tee_dev_destroy(psp);
304
305 dbc_dev_destroy(psp);
306
307 platform_access_dev_destroy(psp);
308
309 sp_free_psp_irq(sp, data: psp);
310
311 if (sp->clear_psp_master_device)
312 sp->clear_psp_master_device(sp);
313}
314
315void psp_set_sev_irq_handler(struct psp_device *psp, psp_irq_handler_t handler,
316 void *data)
317{
318 psp->sev_irq_data = data;
319 psp->sev_irq_handler = handler;
320}
321
322void psp_clear_sev_irq_handler(struct psp_device *psp)
323{
324 psp_set_sev_irq_handler(psp, NULL, NULL);
325}
326
327struct psp_device *psp_get_master_device(void)
328{
329 struct sp_device *sp = sp_get_psp_master_device();
330
331 return sp ? sp->psp_data : NULL;
332}
333
334void psp_pci_init(void)
335{
336 psp_master = psp_get_master_device();
337
338 if (!psp_master)
339 return;
340
341 sev_pci_init();
342}
343
344void psp_pci_exit(void)
345{
346 if (!psp_master)
347 return;
348
349 sev_pci_exit();
350}
351

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source code of linux/drivers/crypto/ccp/psp-dev.c