1 /*
2 * Copyright (c) 2019-2020, ARM Limited and Contributors. All rights reserved.
3 *
4 * SPDX-License-Identifier: BSD-3-Clause
5 */
6
7 #include <assert.h>
8 #include <string.h>
9
10 #include <arch_helpers.h>
11 #include <common/debug.h>
12 #include <lib/utils.h>
13 #include <plat/common/platform.h>
14
15 #include <brcm_mhu.h>
16 #include <brcm_scpi.h>
17 #include <platform_def.h>
18
19 #define SCPI_SHARED_MEM_SCP_TO_AP (PLAT_SCP_COM_SHARED_MEM_BASE)
20 #define SCPI_SHARED_MEM_AP_TO_SCP (PLAT_SCP_COM_SHARED_MEM_BASE \
21 + 0x100)
22
23 /* Header and payload addresses for commands from AP to SCP */
24 #define SCPI_CMD_HEADER_AP_TO_SCP \
25 ((scpi_cmd_t *) SCPI_SHARED_MEM_AP_TO_SCP)
26 #define SCPI_CMD_PAYLOAD_AP_TO_SCP \
27 ((void *) (SCPI_SHARED_MEM_AP_TO_SCP + sizeof(scpi_cmd_t)))
28
29 /* Header and payload addresses for responses from SCP to AP */
30 #define SCPI_RES_HEADER_SCP_TO_AP \
31 ((scpi_cmd_t *) SCPI_SHARED_MEM_SCP_TO_AP)
32 #define SCPI_RES_PAYLOAD_SCP_TO_AP \
33 ((void *) (SCPI_SHARED_MEM_SCP_TO_AP + sizeof(scpi_cmd_t)))
34
35 /* ID of the MHU slot used for the SCPI protocol */
36 #define SCPI_MHU_SLOT_ID 0
37
scpi_secure_message_start(void)38 static void scpi_secure_message_start(void)
39 {
40 mhu_secure_message_start(SCPI_MHU_SLOT_ID);
41 }
42
scpi_secure_message_send(size_t payload_size)43 static void scpi_secure_message_send(size_t payload_size)
44 {
45 /*
46 * Ensure that any write to the SCPI payload area is seen by SCP before
47 * we write to the MHU register. If these 2 writes were reordered by
48 * the CPU then SCP would read stale payload data
49 */
50 dmbst();
51
52 mhu_secure_message_send(SCPI_MHU_SLOT_ID);
53 }
54
scpi_secure_message_receive(scpi_cmd_t * cmd)55 static void scpi_secure_message_receive(scpi_cmd_t *cmd)
56 {
57 uint32_t mhu_status;
58
59 assert(cmd != NULL);
60
61 mhu_status = mhu_secure_message_wait();
62
63 /* Expect an SCPI message, reject any other protocol */
64 if (mhu_status != (1 << SCPI_MHU_SLOT_ID)) {
65 ERROR("MHU: Unexpected protocol (MHU status: 0x%x)\n",
66 mhu_status);
67 panic();
68 }
69
70 /*
71 * Ensure that any read to the SCPI payload area is done after reading
72 * the MHU register. If these 2 reads were reordered then the CPU would
73 * read invalid payload data
74 */
75 dmbld();
76
77 memcpy(cmd, (void *) SCPI_SHARED_MEM_SCP_TO_AP, sizeof(*cmd));
78 }
79
scpi_secure_message_end(void)80 static void scpi_secure_message_end(void)
81 {
82 mhu_secure_message_end(SCPI_MHU_SLOT_ID);
83 }
84
scpi_wait_ready(void)85 int scpi_wait_ready(void)
86 {
87 scpi_cmd_t scpi_cmd;
88
89 VERBOSE("Waiting for SCP_READY command...\n");
90
91 /* Get a message from the SCP */
92 scpi_secure_message_start();
93 scpi_secure_message_receive(&scpi_cmd);
94 scpi_secure_message_end();
95
96 /* We are expecting 'SCP Ready', produce correct error if it's not */
97 scpi_status_t status = SCP_OK;
98
99 if (scpi_cmd.id != SCPI_CMD_SCP_READY) {
100 ERROR("Unexpected SCP command: expected #%u, received #%u\n",
101 SCPI_CMD_SCP_READY, scpi_cmd.id);
102 status = SCP_E_SUPPORT;
103 } else if (scpi_cmd.size != 0) {
104 ERROR("SCP_READY cmd has incorrect size: expected 0, got %u\n",
105 scpi_cmd.size);
106 status = SCP_E_SIZE;
107 }
108
109 VERBOSE("Sending response for SCP_READY command\n");
110
111 /*
112 * Send our response back to SCP.
113 * We are using the same SCPI header, just update the status field.
114 */
115 scpi_cmd.status = status;
116 scpi_secure_message_start();
117 memcpy((void *) SCPI_SHARED_MEM_AP_TO_SCP, &scpi_cmd, sizeof(scpi_cmd));
118 scpi_secure_message_send(0);
119 scpi_secure_message_end();
120
121 return status == SCP_OK ? 0 : -1;
122 }
123
scpi_set_brcm_power_state(unsigned int mpidr,scpi_power_state_t cpu_state,scpi_power_state_t cluster_state,scpi_power_state_t brcm_state)124 void scpi_set_brcm_power_state(unsigned int mpidr,
125 scpi_power_state_t cpu_state, scpi_power_state_t cluster_state,
126 scpi_power_state_t brcm_state)
127 {
128 scpi_cmd_t *cmd;
129 uint32_t state = 0;
130 uint32_t *payload_addr;
131
132 #if ARM_PLAT_MT
133 /*
134 * The current SCPI driver only caters for single-threaded platforms.
135 * Hence we ignore the thread ID (which is always 0) for such platforms.
136 */
137 state |= (mpidr >> MPIDR_AFF1_SHIFT) & 0x0f; /* CPU ID */
138 state |= ((mpidr >> MPIDR_AFF2_SHIFT) & 0x0f) << 4; /* Cluster ID */
139 #else
140 state |= mpidr & 0x0f; /* CPU ID */
141 state |= (mpidr & 0xf00) >> 4; /* Cluster ID */
142 #endif /* ARM_PLAT_MT */
143
144 state |= cpu_state << 8;
145 state |= cluster_state << 12;
146 state |= brcm_state << 16;
147
148 scpi_secure_message_start();
149
150 /* Populate the command header */
151 cmd = SCPI_CMD_HEADER_AP_TO_SCP;
152 cmd->id = SCPI_CMD_SET_POWER_STATE;
153 cmd->set = SCPI_SET_NORMAL;
154 cmd->sender = 0;
155 cmd->size = sizeof(state);
156 /* Populate the command payload */
157 payload_addr = SCPI_CMD_PAYLOAD_AP_TO_SCP;
158 *payload_addr = state;
159 scpi_secure_message_send(sizeof(state));
160
161 /*
162 * SCP does not reply to this command in order to avoid MHU interrupts
163 * from the sender, which could interfere with its power state request.
164 */
165 scpi_secure_message_end();
166 }
167
168 /*
169 * Query and obtain power state from SCP.
170 *
171 * In response to the query, SCP returns power states of all CPUs in all
172 * clusters of the system. The returned response is then filtered based on the
173 * supplied MPIDR. Power states of requested cluster and CPUs within are updated
174 * via. supplied non-NULL pointer arguments.
175 *
176 * Returns 0 on success, or -1 on errors.
177 */
scpi_get_brcm_power_state(unsigned int mpidr,unsigned int * cpu_state_p,unsigned int * cluster_state_p)178 int scpi_get_brcm_power_state(unsigned int mpidr, unsigned int *cpu_state_p,
179 unsigned int *cluster_state_p)
180 {
181 scpi_cmd_t *cmd;
182 scpi_cmd_t response;
183 int power_state, cpu, cluster, rc = -1;
184
185 /*
186 * Extract CPU and cluster membership of the given MPIDR. SCPI caters
187 * for only up to 0xf clusters, and 8 CPUs per cluster
188 */
189 cpu = mpidr & MPIDR_AFFLVL_MASK;
190 cluster = (mpidr >> MPIDR_AFF1_SHIFT) & MPIDR_AFFLVL_MASK;
191 if (cpu >= 8 || cluster >= 0xf)
192 return -1;
193
194 scpi_secure_message_start();
195
196 /* Populate request headers */
197 zeromem(SCPI_CMD_HEADER_AP_TO_SCP, sizeof(*cmd));
198 cmd = SCPI_CMD_HEADER_AP_TO_SCP;
199 cmd->id = SCPI_CMD_GET_POWER_STATE;
200
201 /*
202 * Send message and wait for SCP's response
203 */
204 scpi_secure_message_send(0);
205 scpi_secure_message_receive(&response);
206
207 if (response.status != SCP_OK)
208 goto exit;
209
210 /* Validate SCP response */
211 if (!CHECK_RESPONSE(response, cluster))
212 goto exit;
213
214 /* Extract power states for required cluster */
215 power_state = *(((uint16_t *) SCPI_RES_PAYLOAD_SCP_TO_AP) + cluster);
216 if (CLUSTER_ID(power_state) != cluster)
217 goto exit;
218
219 /* Update power state via. pointers */
220 if (cluster_state_p)
221 *cluster_state_p = CLUSTER_POWER_STATE(power_state);
222 if (cpu_state_p)
223 *cpu_state_p = CPU_POWER_STATE(power_state);
224 rc = 0;
225
226 exit:
227 scpi_secure_message_end();
228 return rc;
229 }
230
scpi_sys_power_state(scpi_system_state_t system_state)231 uint32_t scpi_sys_power_state(scpi_system_state_t system_state)
232 {
233 scpi_cmd_t *cmd;
234 uint8_t *payload_addr;
235
236 scpi_secure_message_start();
237
238 /* Populate the command header */
239 cmd = SCPI_CMD_HEADER_AP_TO_SCP;
240 cmd->id = SCPI_CMD_SYS_POWER_STATE;
241 cmd->set = 0;
242 cmd->sender = 0;
243 cmd->size = sizeof(*payload_addr);
244 /* Populate the command payload */
245 payload_addr = SCPI_CMD_PAYLOAD_AP_TO_SCP;
246 *payload_addr = system_state & 0xff;
247 scpi_secure_message_send(sizeof(*payload_addr));
248
249 scpi_secure_message_end();
250
251 return SCP_OK;
252 }
253