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
 23struct psp_device *psp_master;
 24
 25#define PSP_C2PMSG_17_CMDRESP_CMD	GENMASK(19, 16)
 26
 27static int psp_mailbox_poll(const void __iomem *cmdresp_reg, unsigned int *cmdresp,
 28			    unsigned int timeout_msecs)
 29{
 30	while (true) {
 31		*cmdresp = ioread32(cmdresp_reg);
 32		if (FIELD_GET(PSP_CMDRESP_RESP, *cmdresp))
 33			return 0;
 34
 35		if (!timeout_msecs--)
 36			break;
 37
 38		usleep_range(1000, 1100);
 39	}
 40
 41	return -ETIMEDOUT;
 42}
 43
 44int psp_mailbox_command(struct psp_device *psp, enum psp_cmd cmd, void *cmdbuff,
 45			unsigned int timeout_msecs, unsigned int *cmdresp)
 46{
 47	void __iomem *cmdresp_reg, *cmdbuff_lo_reg, *cmdbuff_hi_reg;
 48	int ret;
 49
 50	if (!psp || !psp->vdata || !psp->vdata->cmdresp_reg ||
 51	    !psp->vdata->cmdbuff_addr_lo_reg || !psp->vdata->cmdbuff_addr_hi_reg)
 52		return -ENODEV;
 53
 54	cmdresp_reg    = psp->io_regs + psp->vdata->cmdresp_reg;
 55	cmdbuff_lo_reg = psp->io_regs + psp->vdata->cmdbuff_addr_lo_reg;
 56	cmdbuff_hi_reg = psp->io_regs + psp->vdata->cmdbuff_addr_hi_reg;
 57
 58	mutex_lock(&psp->mailbox_mutex);
 59
 60	/* Ensure mailbox is ready for a command */
 61	ret = -EBUSY;
 62	if (psp_mailbox_poll(cmdresp_reg, cmdresp, 0))
 63		goto unlock;
 64
 65	if (cmdbuff) {
 66		iowrite32(lower_32_bits(__psp_pa(cmdbuff)), cmdbuff_lo_reg);
 67		iowrite32(upper_32_bits(__psp_pa(cmdbuff)), cmdbuff_hi_reg);
 68	}
 69
 70	*cmdresp = FIELD_PREP(PSP_C2PMSG_17_CMDRESP_CMD, cmd);
 71	iowrite32(*cmdresp, cmdresp_reg);
 72
 73	ret = psp_mailbox_poll(cmdresp_reg, cmdresp, timeout_msecs);
 74
 75unlock:
 76	mutex_unlock(&psp->mailbox_mutex);
 77
 78	return ret;
 79}
 80
 81int psp_extended_mailbox_cmd(struct psp_device *psp, unsigned int timeout_msecs,
 82			     struct psp_ext_request *req)
 83{
 84	unsigned int reg;
 85	int ret;
 86
 87	print_hex_dump_debug("->psp ", DUMP_PREFIX_OFFSET, 16, 2, req,
 88			     req->header.payload_size, false);
 89
 90	ret = psp_mailbox_command(psp, PSP_CMD_TEE_EXTENDED_CMD, (void *)req,
 91				  timeout_msecs, &reg);
 92	if (ret) {
 93		return ret;
 94	} else if (FIELD_GET(PSP_CMDRESP_STS, reg)) {
 95		req->header.status = FIELD_GET(PSP_CMDRESP_STS, reg);
 96		return -EIO;
 97	}
 98
 99	print_hex_dump_debug("<-psp ", DUMP_PREFIX_OFFSET, 16, 2, req,
100			     req->header.payload_size, false);
101
102	return 0;
103}
104
105static struct psp_device *psp_alloc_struct(struct sp_device *sp)
106{
107	struct device *dev = sp->dev;
108	struct psp_device *psp;
109
110	psp = devm_kzalloc(dev, sizeof(*psp), GFP_KERNEL);
111	if (!psp)
112		return NULL;
113
114	psp->dev = dev;
115	psp->sp = sp;
116
117	snprintf(psp->name, sizeof(psp->name), "psp-%u", sp->ord);
118
119	return psp;
120}
121
122static irqreturn_t psp_irq_handler(int irq, void *data)
123{
124	struct psp_device *psp = data;
125	unsigned int status;
126
127	/* Read the interrupt status: */
128	status = ioread32(psp->io_regs + psp->vdata->intsts_reg);
129
130	/* Clear the interrupt status by writing the same value we read. */
131	iowrite32(status, psp->io_regs + psp->vdata->intsts_reg);
132
133	/* invoke subdevice interrupt handlers */
134	if (status) {
135		if (psp->sev_irq_handler)
136			psp->sev_irq_handler(irq, psp->sev_irq_data, status);
137	}
138
139	return IRQ_HANDLED;
140}
141
142static unsigned int psp_get_capability(struct psp_device *psp)
143{
144	unsigned int val = ioread32(psp->io_regs + psp->vdata->feature_reg);
145
146	/*
147	 * Check for a access to the registers.  If this read returns
148	 * 0xffffffff, it's likely that the system is running a broken
149	 * BIOS which disallows access to the device. Stop here and
150	 * fail the PSP initialization (but not the load, as the CCP
151	 * could get properly initialized).
152	 */
153	if (val == 0xffffffff) {
154		dev_notice(psp->dev, "psp: unable to access the device: you might be running a broken BIOS.\n");
155		return -ENODEV;
156	}
157	psp->capability = val;
158
159	/* Detect if TSME and SME are both enabled */
160	if (PSP_CAPABILITY(psp, PSP_SECURITY_REPORTING) &&
161	    psp->capability & (PSP_SECURITY_TSME_STATUS << PSP_CAPABILITY_PSP_SECURITY_OFFSET) &&
162	    cc_platform_has(CC_ATTR_HOST_MEM_ENCRYPT))
163		dev_notice(psp->dev, "psp: Both TSME and SME are active, SME is unnecessary when TSME is active.\n");
164
165	return 0;
166}
167
168static int psp_check_sev_support(struct psp_device *psp)
169{
170	/* Check if device supports SEV feature */
171	if (!PSP_CAPABILITY(psp, SEV)) {
172		dev_dbg(psp->dev, "psp does not support SEV\n");
173		return -ENODEV;
174	}
175
176	return 0;
177}
178
179static int psp_check_tee_support(struct psp_device *psp)
180{
181	/* Check if device supports TEE feature */
182	if (!PSP_CAPABILITY(psp, TEE)) {
183		dev_dbg(psp->dev, "psp does not support TEE\n");
184		return -ENODEV;
185	}
186
187	return 0;
188}
189
190static int psp_init(struct psp_device *psp)
191{
192	int ret;
193
194	if (!psp_check_sev_support(psp)) {
195		ret = sev_dev_init(psp);
196		if (ret)
197			return ret;
198	}
199
200	if (!psp_check_tee_support(psp)) {
201		ret = tee_dev_init(psp);
202		if (ret)
203			return ret;
204	}
205
206	if (psp->vdata->platform_access) {
207		ret = platform_access_dev_init(psp);
208		if (ret)
209			return ret;
210	}
211
212	/* dbc must come after platform access as it tests the feature */
213	if (PSP_FEATURE(psp, DBC) ||
214	    PSP_CAPABILITY(psp, DBC_THRU_EXT)) {
215		ret = dbc_dev_init(psp);
216		if (ret)
217			return ret;
218	}
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(psp->sp, psp_irq_handler, psp->name, 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(psp->sp, 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, 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}