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(1000, 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, 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(&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, PSP_CMD_TEE_EXTENDED_CMD, (void *)req,
 92				  timeout_msecs, &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, sizeof(*psp), GFP_KERNEL);
112	if (!psp)
113		return NULL;
114
115	psp->dev = dev;
116	psp->sp = sp;
117
118	snprintf(psp->name, sizeof(psp->name), "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(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}