xref: /freebsd/sys/dev/mana/shm_channel.c (revision 105fd928b0b5b35ab529e5f6914788dc49582901)
1 /*-
2  * SPDX-License-Identifier: BSD-2-Clause
3  *
4  * Copyright (c) 2021 Microsoft Corp.
5  * All rights reserved.
6  *
7  * Redistribution and use in source and binary forms, with or without
8  * modification, are permitted provided that the following conditions
9  * are met:
10  *
11  * 1. Redistributions of source code must retain the above copyright
12  *    notice, this list of conditions and the following disclaimer.
13  *
14  * 2. Redistributions in binary form must reproduce the above copyright
15  *    notice, this list of conditions and the following disclaimer in the
16  *    documentation and/or other materials provided with the distribution.
17  *
18  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
19  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
20  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
21  * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
22  * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
23  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
24  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
25  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
26  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
27  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
28  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
29  */
30 #include <sys/cdefs.h>
31 __FBSDID("$FreeBSD$");
32 
33 #include <sys/param.h>
34 #include <sys/types.h>
35 #include <sys/systm.h>
36 #include <sys/bus.h>
37 
38 #include "mana.h"
39 #include "shm_channel.h"
40 #include "gdma_util.h"
41 
42 #define PAGE_FRAME_L48_WIDTH_BYTES 6
43 #define PAGE_FRAME_L48_WIDTH_BITS (PAGE_FRAME_L48_WIDTH_BYTES * 8)
44 #define PAGE_FRAME_L48_MASK 0x0000FFFFFFFFFFFF
45 #define PAGE_FRAME_H4_WIDTH_BITS 4
46 #define VECTOR_MASK 0xFFFF
47 #define SHMEM_VF_RESET_STATE ((uint32_t)-1)
48 
49 #define SMC_MSG_TYPE_ESTABLISH_HWC 1
50 #define SMC_MSG_TYPE_ESTABLISH_HWC_VERSION 0
51 
52 #define SMC_MSG_TYPE_DESTROY_HWC 2
53 #define SMC_MSG_TYPE_DESTROY_HWC_VERSION 0
54 
55 #define SMC_MSG_DIRECTION_REQUEST 0
56 #define SMC_MSG_DIRECTION_RESPONSE 1
57 
58 /* Structures labeled with "HW DATA" are exchanged with the hardware. All of
59  * them are naturally aligned and hence don't need __packed.
60  */
61 
62 /* Shared memory channel protocol header
63  *
64  * msg_type: set on request and response; response matches request.
65  * msg_version: newer PF writes back older response (matching request)
66  *  older PF acts on latest version known and sets that version in result
67  *  (less than request).
68  * direction: 0 for request, VF->PF; 1 for response, PF->VF.
69  * status: 0 on request,
70  *   operation result on response (success = 0, failure = 1 or greater).
71  * reset_vf: If set on either establish or destroy request, indicates perform
72  *  FLR before/after the operation.
73  * owner_is_pf: 1 indicates PF owned, 0 indicates VF owned.
74  */
75 union smc_proto_hdr {
76 	uint32_t as_uint32;
77 
78 	struct {
79 		uint8_t msg_type	: 3;
80 		uint8_t msg_version	: 3;
81 		uint8_t reserved_1	: 1;
82 		uint8_t direction	: 1;
83 
84 		uint8_t status;
85 
86 		uint8_t reserved_2;
87 
88 		uint8_t reset_vf	: 1;
89 		uint8_t reserved_3	: 6;
90 		uint8_t owner_is_pf	: 1;
91 	};
92 }; /* HW DATA */
93 
94 #define SMC_APERTURE_BITS 256
95 #define SMC_BASIC_UNIT (sizeof(uint32_t))
96 #define SMC_APERTURE_DWORDS (SMC_APERTURE_BITS / (SMC_BASIC_UNIT * 8))
97 #define SMC_LAST_DWORD (SMC_APERTURE_DWORDS - 1)
98 
99 static int
100 mana_smc_poll_register(void __iomem *base, bool reset)
101 {
102 	void __iomem *ptr = (uint8_t *)base + SMC_LAST_DWORD * SMC_BASIC_UNIT;
103 	volatile uint32_t last_dword;
104 	int i;
105 
106 	/* Poll the hardware for the ownership bit. This should be pretty fast,
107 	 * but let's do it in a loop just in case the hardware or the PF
108 	 * driver are temporarily busy.
109 	 */
110 	for (i = 0; i < 20 * 1000; i++)  {
111 		last_dword = readl(ptr);
112 
113 		/* shmem reads as 0xFFFFFFFF in the reset case */
114 		if (reset && last_dword == SHMEM_VF_RESET_STATE)
115 			return 0;
116 
117 		/* If bit_31 is set, the PF currently owns the SMC. */
118 		if (!(last_dword & BIT(31)))
119 			return 0;
120 
121 		DELAY(1000);
122 	}
123 
124 	return ETIMEDOUT;
125 }
126 
127 static int
128 mana_smc_read_response(struct shm_channel *sc, uint32_t msg_type,
129     uint32_t msg_version, bool reset_vf)
130 {
131 	void __iomem *base = sc->base;
132 	union smc_proto_hdr hdr;
133 	int err;
134 
135 	/* Wait for PF to respond. */
136 	err = mana_smc_poll_register(base, reset_vf);
137 	if (err)
138 		return err;
139 
140 	hdr.as_uint32 =
141 	    readl((uint8_t *)base + SMC_LAST_DWORD * SMC_BASIC_UNIT);
142 	mana_dbg(NULL, "shm response 0x%x\n", hdr.as_uint32);
143 
144 	if (reset_vf && hdr.as_uint32 == SHMEM_VF_RESET_STATE)
145 		return 0;
146 
147 	/* Validate protocol fields from the PF driver */
148 	if (hdr.msg_type != msg_type || hdr.msg_version > msg_version ||
149 	    hdr.direction != SMC_MSG_DIRECTION_RESPONSE) {
150 		device_printf(sc->dev,
151 		    "Wrong SMC response 0x%x, type=%d, ver=%d\n",
152 		    hdr.as_uint32, msg_type, msg_version);
153 		return EPROTO;
154 	}
155 
156 	/* Validate the operation result */
157 	if (hdr.status != 0) {
158 		device_printf(sc->dev,
159 		    "SMC operation failed: 0x%x\n", hdr.status);
160 		return EPROTO;
161 	}
162 
163 	return 0;
164 }
165 
166 void
167 mana_smc_init(struct shm_channel *sc, device_t dev, void __iomem *base)
168 {
169 	sc->dev = dev;
170 	sc->base = base;
171 }
172 
173 int
174 mana_smc_setup_hwc(struct shm_channel *sc, bool reset_vf, uint64_t eq_addr,
175     uint64_t cq_addr, uint64_t rq_addr, uint64_t sq_addr,
176     uint32_t eq_msix_index)
177 {
178 	union smc_proto_hdr *hdr;
179 	uint16_t all_addr_h4bits = 0;
180 	uint16_t frame_addr_seq = 0;
181 	uint64_t frame_addr = 0;
182 	uint8_t shm_buf[32];
183 	uint64_t *shmem;
184 	uint32_t *dword;
185 	uint8_t *ptr;
186 	int err;
187 	int i;
188 
189 	/* Ensure VF already has possession of shared memory */
190 	err = mana_smc_poll_register(sc->base, false);
191 	if (err) {
192 		device_printf(sc->dev,
193 		    "Timeout when setting up HWC: %d\n", err);
194 		return err;
195 	}
196 
197 	if (!IS_ALIGNED(eq_addr, PAGE_SIZE) ||
198 	    !IS_ALIGNED(cq_addr, PAGE_SIZE) ||
199 	    !IS_ALIGNED(rq_addr, PAGE_SIZE) ||
200 	    !IS_ALIGNED(sq_addr, PAGE_SIZE))
201 		return EINVAL;
202 
203 	if ((eq_msix_index & VECTOR_MASK) != eq_msix_index)
204 		return EINVAL;
205 
206 	/* Scheme for packing four addresses and extra info into 256 bits.
207 	 *
208 	 * Addresses must be page frame aligned, so only frame address bits
209 	 * are transferred.
210 	 *
211 	 * 52-bit frame addresses are split into the lower 48 bits and upper
212 	 * 4 bits. Lower 48 bits of 4 address are written sequentially from
213 	 * the start of the 256-bit shared memory region followed by 16 bits
214 	 * containing the upper 4 bits of the 4 addresses in sequence.
215 	 *
216 	 * A 16 bit EQ vector number fills out the next-to-last 32-bit dword.
217 	 *
218 	 * The final 32-bit dword is used for protocol control information as
219 	 * defined in smc_proto_hdr.
220 	 */
221 
222 	memset(shm_buf, 0, sizeof(shm_buf));
223 	ptr = shm_buf;
224 
225 	/* EQ addr: low 48 bits of frame address */
226 	shmem = (uint64_t *)ptr;
227 	frame_addr = PHYS_PFN(eq_addr);
228 	*shmem = frame_addr & PAGE_FRAME_L48_MASK;
229 	all_addr_h4bits |= (frame_addr >> PAGE_FRAME_L48_WIDTH_BITS) <<
230 		(frame_addr_seq++ * PAGE_FRAME_H4_WIDTH_BITS);
231 	ptr += PAGE_FRAME_L48_WIDTH_BYTES;
232 
233 	/* CQ addr: low 48 bits of frame address */
234 	shmem = (uint64_t *)ptr;
235 	frame_addr = PHYS_PFN(cq_addr);
236 	*shmem = frame_addr & PAGE_FRAME_L48_MASK;
237 	all_addr_h4bits |= (frame_addr >> PAGE_FRAME_L48_WIDTH_BITS) <<
238 		(frame_addr_seq++ * PAGE_FRAME_H4_WIDTH_BITS);
239 	ptr += PAGE_FRAME_L48_WIDTH_BYTES;
240 
241 	/* RQ addr: low 48 bits of frame address */
242 	shmem = (uint64_t *)ptr;
243 	frame_addr = PHYS_PFN(rq_addr);
244 	*shmem = frame_addr & PAGE_FRAME_L48_MASK;
245 	all_addr_h4bits |= (frame_addr >> PAGE_FRAME_L48_WIDTH_BITS) <<
246 		(frame_addr_seq++ * PAGE_FRAME_H4_WIDTH_BITS);
247 	ptr += PAGE_FRAME_L48_WIDTH_BYTES;
248 
249 	/* SQ addr: low 48 bits of frame address */
250 	shmem = (uint64_t *)ptr;
251 	frame_addr = PHYS_PFN(sq_addr);
252 	*shmem = frame_addr & PAGE_FRAME_L48_MASK;
253 	all_addr_h4bits |= (frame_addr >> PAGE_FRAME_L48_WIDTH_BITS) <<
254 		(frame_addr_seq++ * PAGE_FRAME_H4_WIDTH_BITS);
255 	ptr += PAGE_FRAME_L48_WIDTH_BYTES;
256 
257 	/* High 4 bits of the four frame addresses */
258 	*((uint16_t *)ptr) = all_addr_h4bits;
259 	ptr += sizeof(uint16_t);
260 
261 	/* EQ MSIX vector number */
262 	*((uint16_t *)ptr) = (uint16_t)eq_msix_index;
263 	ptr += sizeof(uint16_t);
264 
265 	/* 32-bit protocol header in final dword */
266 	*((uint32_t *)ptr) = 0;
267 
268 	hdr = (union smc_proto_hdr *)ptr;
269 	hdr->msg_type = SMC_MSG_TYPE_ESTABLISH_HWC;
270 	hdr->msg_version = SMC_MSG_TYPE_ESTABLISH_HWC_VERSION;
271 	hdr->direction = SMC_MSG_DIRECTION_REQUEST;
272 	hdr->reset_vf = reset_vf;
273 
274 	/* Write 256-message buffer to shared memory (final 32-bit write
275 	 * triggers HW to set possession bit to PF).
276 	 */
277 	dword = (uint32_t *)shm_buf;
278 	for (i = 0; i < SMC_APERTURE_DWORDS; i++) {
279 		mana_dbg(NULL, "write shm_buf %d, val: 0x%x\n",
280 		    i, *dword);
281 		writel((char *)sc->base + i * SMC_BASIC_UNIT, *dword++);
282 	}
283 
284 	/* Read shmem response (polling for VF possession) and validate.
285 	 * For setup, waiting for response on shared memory is not strictly
286 	 * necessary, since wait occurs later for results to appear in EQE's.
287 	 */
288 	err = mana_smc_read_response(sc, SMC_MSG_TYPE_ESTABLISH_HWC,
289 	    SMC_MSG_TYPE_ESTABLISH_HWC_VERSION, reset_vf);
290 	if (err) {
291 		device_printf(sc->dev,
292 		    "Error when setting up HWC: %d\n", err);
293 		return err;
294 	}
295 
296 	return 0;
297 }
298 
299 int
300 mana_smc_teardown_hwc(struct shm_channel *sc, bool reset_vf)
301 {
302 	union smc_proto_hdr hdr = {};
303 	int err;
304 
305 	/* Ensure already has possession of shared memory */
306 	err = mana_smc_poll_register(sc->base, false);
307 	if (err) {
308 		device_printf(sc->dev, "Timeout when tearing down HWC\n");
309 		return err;
310 	}
311 
312 	/* Set up protocol header for HWC destroy message */
313 	hdr.msg_type = SMC_MSG_TYPE_DESTROY_HWC;
314 	hdr.msg_version = SMC_MSG_TYPE_DESTROY_HWC_VERSION;
315 	hdr.direction = SMC_MSG_DIRECTION_REQUEST;
316 	hdr.reset_vf = reset_vf;
317 
318 	/* Write message in high 32 bits of 256-bit shared memory, causing HW
319 	 * to set possession bit to PF.
320 	 */
321 	writel((char *)sc->base + SMC_LAST_DWORD * SMC_BASIC_UNIT,
322 	    hdr.as_uint32);
323 
324 	/* Read shmem response (polling for VF possession) and validate.
325 	 * For teardown, waiting for response is required to ensure hardware
326 	 * invalidates MST entries before software frees memory.
327 	 */
328 	err = mana_smc_read_response(sc, SMC_MSG_TYPE_DESTROY_HWC,
329 	    SMC_MSG_TYPE_DESTROY_HWC_VERSION, reset_vf);
330 	if (err) {
331 		device_printf(sc->dev,
332 		    "Error when tearing down HWC: %d\n", err);
333 		return err;
334 	}
335 
336 	return 0;
337 }
338