xref: /freebsd/sys/dev/mana/shm_channel.c (revision edf8578117e8844e02c0121147f45e4609b30680)
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 #include <sys/param.h>
32 #include <sys/types.h>
33 #include <sys/systm.h>
34 #include <sys/bus.h>
35 
36 #include "mana.h"
37 #include "shm_channel.h"
38 #include "gdma_util.h"
39 
40 #define PAGE_FRAME_L48_WIDTH_BYTES 6
41 #define PAGE_FRAME_L48_WIDTH_BITS (PAGE_FRAME_L48_WIDTH_BYTES * 8)
42 #define PAGE_FRAME_L48_MASK 0x0000FFFFFFFFFFFF
43 #define PAGE_FRAME_H4_WIDTH_BITS 4
44 #define VECTOR_MASK 0xFFFF
45 #define SHMEM_VF_RESET_STATE ((uint32_t)-1)
46 
47 #define SMC_MSG_TYPE_ESTABLISH_HWC 1
48 #define SMC_MSG_TYPE_ESTABLISH_HWC_VERSION 0
49 
50 #define SMC_MSG_TYPE_DESTROY_HWC 2
51 #define SMC_MSG_TYPE_DESTROY_HWC_VERSION 0
52 
53 #define SMC_MSG_DIRECTION_REQUEST 0
54 #define SMC_MSG_DIRECTION_RESPONSE 1
55 
56 /* Structures labeled with "HW DATA" are exchanged with the hardware. All of
57  * them are naturally aligned and hence don't need __packed.
58  */
59 
60 /* Shared memory channel protocol header
61  *
62  * msg_type: set on request and response; response matches request.
63  * msg_version: newer PF writes back older response (matching request)
64  *  older PF acts on latest version known and sets that version in result
65  *  (less than request).
66  * direction: 0 for request, VF->PF; 1 for response, PF->VF.
67  * status: 0 on request,
68  *   operation result on response (success = 0, failure = 1 or greater).
69  * reset_vf: If set on either establish or destroy request, indicates perform
70  *  FLR before/after the operation.
71  * owner_is_pf: 1 indicates PF owned, 0 indicates VF owned.
72  */
73 union smc_proto_hdr {
74 	uint32_t as_uint32;
75 
76 	struct {
77 		uint8_t msg_type	: 3;
78 		uint8_t msg_version	: 3;
79 		uint8_t reserved_1	: 1;
80 		uint8_t direction	: 1;
81 
82 		uint8_t status;
83 
84 		uint8_t reserved_2;
85 
86 		uint8_t reset_vf	: 1;
87 		uint8_t reserved_3	: 6;
88 		uint8_t owner_is_pf	: 1;
89 	};
90 }; /* HW DATA */
91 
92 #define SMC_APERTURE_BITS 256
93 #define SMC_BASIC_UNIT (sizeof(uint32_t))
94 #define SMC_APERTURE_DWORDS (SMC_APERTURE_BITS / (SMC_BASIC_UNIT * 8))
95 #define SMC_LAST_DWORD (SMC_APERTURE_DWORDS - 1)
96 
97 static int
98 mana_smc_poll_register(void __iomem *base, bool reset)
99 {
100 	void __iomem *ptr = (uint8_t *)base + SMC_LAST_DWORD * SMC_BASIC_UNIT;
101 	volatile uint32_t last_dword;
102 	int i;
103 
104 	/* Poll the hardware for the ownership bit. This should be pretty fast,
105 	 * but let's do it in a loop just in case the hardware or the PF
106 	 * driver are temporarily busy.
107 	 */
108 	for (i = 0; i < 20 * 1000; i++)  {
109 		last_dword = readl(ptr);
110 
111 		/* shmem reads as 0xFFFFFFFF in the reset case */
112 		if (reset && last_dword == SHMEM_VF_RESET_STATE)
113 			return 0;
114 
115 		/* If bit_31 is set, the PF currently owns the SMC. */
116 		if (!(last_dword & BIT(31)))
117 			return 0;
118 
119 		DELAY(1000);
120 	}
121 
122 	return ETIMEDOUT;
123 }
124 
125 static int
126 mana_smc_read_response(struct shm_channel *sc, uint32_t msg_type,
127     uint32_t msg_version, bool reset_vf)
128 {
129 	void __iomem *base = sc->base;
130 	union smc_proto_hdr hdr;
131 	int err;
132 
133 	/* Wait for PF to respond. */
134 	err = mana_smc_poll_register(base, reset_vf);
135 	if (err)
136 		return err;
137 
138 	hdr.as_uint32 =
139 	    readl((uint8_t *)base + SMC_LAST_DWORD * SMC_BASIC_UNIT);
140 	mana_dbg(NULL, "shm response 0x%x\n", hdr.as_uint32);
141 
142 	if (reset_vf && hdr.as_uint32 == SHMEM_VF_RESET_STATE)
143 		return 0;
144 
145 	/* Validate protocol fields from the PF driver */
146 	if (hdr.msg_type != msg_type || hdr.msg_version > msg_version ||
147 	    hdr.direction != SMC_MSG_DIRECTION_RESPONSE) {
148 		device_printf(sc->dev,
149 		    "Wrong SMC response 0x%x, type=%d, ver=%d\n",
150 		    hdr.as_uint32, msg_type, msg_version);
151 		return EPROTO;
152 	}
153 
154 	/* Validate the operation result */
155 	if (hdr.status != 0) {
156 		device_printf(sc->dev,
157 		    "SMC operation failed: 0x%x\n", hdr.status);
158 		return EPROTO;
159 	}
160 
161 	return 0;
162 }
163 
164 void
165 mana_smc_init(struct shm_channel *sc, device_t dev, void __iomem *base)
166 {
167 	sc->dev = dev;
168 	sc->base = base;
169 }
170 
171 int
172 mana_smc_setup_hwc(struct shm_channel *sc, bool reset_vf, uint64_t eq_addr,
173     uint64_t cq_addr, uint64_t rq_addr, uint64_t sq_addr,
174     uint32_t eq_msix_index)
175 {
176 	union smc_proto_hdr *hdr;
177 	uint16_t all_addr_h4bits = 0;
178 	uint16_t frame_addr_seq = 0;
179 	uint64_t frame_addr = 0;
180 	uint8_t shm_buf[32];
181 	uint64_t *shmem;
182 	uint32_t *dword;
183 	uint8_t *ptr;
184 	int err;
185 	int i;
186 
187 	/* Ensure VF already has possession of shared memory */
188 	err = mana_smc_poll_register(sc->base, false);
189 	if (err) {
190 		device_printf(sc->dev,
191 		    "Timeout when setting up HWC: %d\n", err);
192 		return err;
193 	}
194 
195 	if (!IS_ALIGNED(eq_addr, PAGE_SIZE) ||
196 	    !IS_ALIGNED(cq_addr, PAGE_SIZE) ||
197 	    !IS_ALIGNED(rq_addr, PAGE_SIZE) ||
198 	    !IS_ALIGNED(sq_addr, PAGE_SIZE))
199 		return EINVAL;
200 
201 	if ((eq_msix_index & VECTOR_MASK) != eq_msix_index)
202 		return EINVAL;
203 
204 	/* Scheme for packing four addresses and extra info into 256 bits.
205 	 *
206 	 * Addresses must be page frame aligned, so only frame address bits
207 	 * are transferred.
208 	 *
209 	 * 52-bit frame addresses are split into the lower 48 bits and upper
210 	 * 4 bits. Lower 48 bits of 4 address are written sequentially from
211 	 * the start of the 256-bit shared memory region followed by 16 bits
212 	 * containing the upper 4 bits of the 4 addresses in sequence.
213 	 *
214 	 * A 16 bit EQ vector number fills out the next-to-last 32-bit dword.
215 	 *
216 	 * The final 32-bit dword is used for protocol control information as
217 	 * defined in smc_proto_hdr.
218 	 */
219 
220 	memset(shm_buf, 0, sizeof(shm_buf));
221 	ptr = shm_buf;
222 
223 	/* EQ addr: low 48 bits of frame address */
224 	shmem = (uint64_t *)ptr;
225 	frame_addr = PHYS_PFN(eq_addr);
226 	*shmem = frame_addr & PAGE_FRAME_L48_MASK;
227 	all_addr_h4bits |= (frame_addr >> PAGE_FRAME_L48_WIDTH_BITS) <<
228 		(frame_addr_seq++ * PAGE_FRAME_H4_WIDTH_BITS);
229 	ptr += PAGE_FRAME_L48_WIDTH_BYTES;
230 
231 	/* CQ addr: low 48 bits of frame address */
232 	shmem = (uint64_t *)ptr;
233 	frame_addr = PHYS_PFN(cq_addr);
234 	*shmem = frame_addr & PAGE_FRAME_L48_MASK;
235 	all_addr_h4bits |= (frame_addr >> PAGE_FRAME_L48_WIDTH_BITS) <<
236 		(frame_addr_seq++ * PAGE_FRAME_H4_WIDTH_BITS);
237 	ptr += PAGE_FRAME_L48_WIDTH_BYTES;
238 
239 	/* RQ addr: low 48 bits of frame address */
240 	shmem = (uint64_t *)ptr;
241 	frame_addr = PHYS_PFN(rq_addr);
242 	*shmem = frame_addr & PAGE_FRAME_L48_MASK;
243 	all_addr_h4bits |= (frame_addr >> PAGE_FRAME_L48_WIDTH_BITS) <<
244 		(frame_addr_seq++ * PAGE_FRAME_H4_WIDTH_BITS);
245 	ptr += PAGE_FRAME_L48_WIDTH_BYTES;
246 
247 	/* SQ addr: low 48 bits of frame address */
248 	shmem = (uint64_t *)ptr;
249 	frame_addr = PHYS_PFN(sq_addr);
250 	*shmem = frame_addr & PAGE_FRAME_L48_MASK;
251 	all_addr_h4bits |= (frame_addr >> PAGE_FRAME_L48_WIDTH_BITS) <<
252 		(frame_addr_seq++ * PAGE_FRAME_H4_WIDTH_BITS);
253 	ptr += PAGE_FRAME_L48_WIDTH_BYTES;
254 
255 	/* High 4 bits of the four frame addresses */
256 	*((uint16_t *)ptr) = all_addr_h4bits;
257 	ptr += sizeof(uint16_t);
258 
259 	/* EQ MSIX vector number */
260 	*((uint16_t *)ptr) = (uint16_t)eq_msix_index;
261 	ptr += sizeof(uint16_t);
262 
263 	/* 32-bit protocol header in final dword */
264 	*((uint32_t *)ptr) = 0;
265 
266 	hdr = (union smc_proto_hdr *)ptr;
267 	hdr->msg_type = SMC_MSG_TYPE_ESTABLISH_HWC;
268 	hdr->msg_version = SMC_MSG_TYPE_ESTABLISH_HWC_VERSION;
269 	hdr->direction = SMC_MSG_DIRECTION_REQUEST;
270 	hdr->reset_vf = reset_vf;
271 
272 	/* Write 256-message buffer to shared memory (final 32-bit write
273 	 * triggers HW to set possession bit to PF).
274 	 */
275 	dword = (uint32_t *)shm_buf;
276 	for (i = 0; i < SMC_APERTURE_DWORDS; i++) {
277 		mana_dbg(NULL, "write shm_buf %d, val: 0x%x\n",
278 		    i, *dword);
279 		writel((char *)sc->base + i * SMC_BASIC_UNIT, *dword++);
280 	}
281 
282 	/* Read shmem response (polling for VF possession) and validate.
283 	 * For setup, waiting for response on shared memory is not strictly
284 	 * necessary, since wait occurs later for results to appear in EQE's.
285 	 */
286 	err = mana_smc_read_response(sc, SMC_MSG_TYPE_ESTABLISH_HWC,
287 	    SMC_MSG_TYPE_ESTABLISH_HWC_VERSION, reset_vf);
288 	if (err) {
289 		device_printf(sc->dev,
290 		    "Error when setting up HWC: %d\n", err);
291 		return err;
292 	}
293 
294 	return 0;
295 }
296 
297 int
298 mana_smc_teardown_hwc(struct shm_channel *sc, bool reset_vf)
299 {
300 	union smc_proto_hdr hdr = {};
301 	int err;
302 
303 	/* Ensure already has possession of shared memory */
304 	err = mana_smc_poll_register(sc->base, false);
305 	if (err) {
306 		device_printf(sc->dev, "Timeout when tearing down HWC\n");
307 		return err;
308 	}
309 
310 	/* Set up protocol header for HWC destroy message */
311 	hdr.msg_type = SMC_MSG_TYPE_DESTROY_HWC;
312 	hdr.msg_version = SMC_MSG_TYPE_DESTROY_HWC_VERSION;
313 	hdr.direction = SMC_MSG_DIRECTION_REQUEST;
314 	hdr.reset_vf = reset_vf;
315 
316 	/* Write message in high 32 bits of 256-bit shared memory, causing HW
317 	 * to set possession bit to PF.
318 	 */
319 	writel((char *)sc->base + SMC_LAST_DWORD * SMC_BASIC_UNIT,
320 	    hdr.as_uint32);
321 
322 	/* Read shmem response (polling for VF possession) and validate.
323 	 * For teardown, waiting for response is required to ensure hardware
324 	 * invalidates MST entries before software frees memory.
325 	 */
326 	err = mana_smc_read_response(sc, SMC_MSG_TYPE_DESTROY_HWC,
327 	    SMC_MSG_TYPE_DESTROY_HWC_VERSION, reset_vf);
328 	if (err) {
329 		device_printf(sc->dev,
330 		    "Error when tearing down HWC: %d\n", err);
331 		return err;
332 	}
333 
334 	return 0;
335 }
336