1 /*
2 * Copyright (c) 2014-2020, 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 <drivers/arm/css/css_mhu.h>
13 #include <drivers/arm/css/css_scpi.h>
14 #include <lib/utils.h>
15 #include <plat/common/platform.h>
16 #include <platform_def.h>
17
18 #define SCPI_SHARED_MEM_SCP_TO_AP PLAT_CSS_SCP_COM_SHARED_MEM_BASE
19 #define SCPI_SHARED_MEM_AP_TO_SCP (PLAT_CSS_SCP_COM_SHARED_MEM_BASE \
20 + 0x100)
21
22 /* Header and payload addresses for commands from AP to SCP */
23 #define SCPI_CMD_HEADER_AP_TO_SCP \
24 ((scpi_cmd_t *) SCPI_SHARED_MEM_AP_TO_SCP)
25 #define SCPI_CMD_PAYLOAD_AP_TO_SCP \
26 ((void *) (SCPI_SHARED_MEM_AP_TO_SCP + sizeof(scpi_cmd_t)))
27
28 /* Header and payload addresses for responses from SCP to AP */
29 #define SCPI_RES_HEADER_SCP_TO_AP \
30 ((scpi_cmd_t *) SCPI_SHARED_MEM_SCP_TO_AP)
31 #define SCPI_RES_PAYLOAD_SCP_TO_AP \
32 ((void *) (SCPI_SHARED_MEM_SCP_TO_AP + sizeof(scpi_cmd_t)))
33
34 /* ID of the MHU slot used for the SCPI protocol */
35 #define SCPI_MHU_SLOT_ID 0
36
scpi_secure_message_start(void)37 static void scpi_secure_message_start(void)
38 {
39 mhu_secure_message_start(SCPI_MHU_SLOT_ID);
40 }
41
scpi_secure_message_send(size_t payload_size)42 static void scpi_secure_message_send(size_t payload_size)
43 {
44 /*
45 * Ensure that any write to the SCPI payload area is seen by SCP before
46 * we write to the MHU register. If these 2 writes were reordered by
47 * the CPU then SCP would read stale payload data
48 */
49 dmbst();
50
51 mhu_secure_message_send(SCPI_MHU_SLOT_ID);
52 }
53
scpi_secure_message_receive(scpi_cmd_t * cmd)54 static int scpi_secure_message_receive(scpi_cmd_t *cmd)
55 {
56 uint32_t mhu_status;
57
58 assert(cmd != NULL);
59
60 mhu_status = mhu_secure_message_wait();
61
62 /* Expect an SCPI message, reject any other protocol */
63 if (mhu_status != (1 << SCPI_MHU_SLOT_ID)) {
64 ERROR("MHU: Unexpected protocol (MHU status: 0x%x)\n",
65 mhu_status);
66 return -1;
67 }
68
69 /*
70 * Ensure that any read to the SCPI payload area is done after reading
71 * the MHU register. If these 2 reads were reordered then the CPU would
72 * read invalid payload data
73 */
74 dmbld();
75
76 memcpy(cmd, (void *) SCPI_SHARED_MEM_SCP_TO_AP, sizeof(*cmd));
77
78 return 0;
79 }
80
scpi_secure_message_end(void)81 static void scpi_secure_message_end(void)
82 {
83 mhu_secure_message_end(SCPI_MHU_SLOT_ID);
84 }
85
scpi_wait_ready(void)86 int scpi_wait_ready(void)
87 {
88 scpi_cmd_t scpi_cmd;
89 int rc;
90
91 VERBOSE("Waiting for SCP_READY command...\n");
92
93 /* Get a message from the SCP */
94 scpi_secure_message_start();
95 rc = scpi_secure_message_receive(&scpi_cmd);
96 scpi_secure_message_end();
97
98 /* If no message was received, don't send a response */
99 if (rc != 0)
100 return rc;
101
102 /* We are expecting 'SCP Ready', produce correct error if it's not */
103 scpi_status_t status = SCP_OK;
104 if (scpi_cmd.id != SCPI_CMD_SCP_READY) {
105 ERROR("Unexpected SCP command: expected command #%u, got command #%u\n",
106 SCPI_CMD_SCP_READY, scpi_cmd.id);
107 status = SCP_E_SUPPORT;
108 } else if (scpi_cmd.size != 0) {
109 ERROR("SCP_READY command has incorrect size: expected 0, got %u\n",
110 scpi_cmd.size);
111 status = SCP_E_SIZE;
112 }
113
114 VERBOSE("Sending response for SCP_READY command\n");
115
116 /*
117 * Send our response back to SCP.
118 * We are using the same SCPI header, just update the status field.
119 */
120 scpi_cmd.status = status;
121 scpi_secure_message_start();
122 memcpy((void *) SCPI_SHARED_MEM_AP_TO_SCP, &scpi_cmd, sizeof(scpi_cmd));
123 scpi_secure_message_send(0);
124 scpi_secure_message_end();
125
126 return status == SCP_OK ? 0 : -1;
127 }
128
scpi_set_css_power_state(unsigned int mpidr,scpi_power_state_t cpu_state,scpi_power_state_t cluster_state,scpi_power_state_t css_state)129 void scpi_set_css_power_state(unsigned int mpidr,
130 scpi_power_state_t cpu_state, scpi_power_state_t cluster_state,
131 scpi_power_state_t css_state)
132 {
133 scpi_cmd_t *cmd;
134 uint32_t state = 0;
135 uint32_t *payload_addr;
136
137 #if ARM_PLAT_MT
138 /*
139 * The current SCPI driver only caters for single-threaded platforms.
140 * Hence we ignore the thread ID (which is always 0) for such platforms.
141 */
142 state |= (mpidr >> MPIDR_AFF1_SHIFT) & 0x0f; /* CPU ID */
143 state |= ((mpidr >> MPIDR_AFF2_SHIFT) & 0x0f) << 4; /* Cluster ID */
144 #else
145 state |= mpidr & 0x0f; /* CPU ID */
146 state |= (mpidr & 0xf00) >> 4; /* Cluster ID */
147 #endif /* ARM_PLAT_MT */
148
149 state |= cpu_state << 8;
150 state |= cluster_state << 12;
151 state |= css_state << 16;
152
153 scpi_secure_message_start();
154
155 /* Populate the command header */
156 cmd = SCPI_CMD_HEADER_AP_TO_SCP;
157 cmd->id = SCPI_CMD_SET_CSS_POWER_STATE;
158 cmd->set = SCPI_SET_NORMAL;
159 cmd->sender = 0;
160 cmd->size = sizeof(state);
161 /* Populate the command payload */
162 payload_addr = SCPI_CMD_PAYLOAD_AP_TO_SCP;
163 *payload_addr = state;
164 scpi_secure_message_send(sizeof(state));
165 /*
166 * SCP does not reply to this command in order to avoid MHU interrupts
167 * from the sender, which could interfere with its power state request.
168 */
169
170 scpi_secure_message_end();
171 }
172
173 /*
174 * Query and obtain CSS power state from SCP.
175 *
176 * In response to the query, SCP returns power states of all CPUs in all
177 * clusters of the system. The returned response is then filtered based on the
178 * supplied MPIDR. Power states of requested cluster and CPUs within are updated
179 * via supplied non-NULL pointer arguments.
180 *
181 * Returns 0 on success, or -1 on errors.
182 */
scpi_get_css_power_state(unsigned int mpidr,unsigned int * cpu_state_p,unsigned int * cluster_state_p)183 int scpi_get_css_power_state(unsigned int mpidr, unsigned int *cpu_state_p,
184 unsigned int *cluster_state_p)
185 {
186 scpi_cmd_t *cmd;
187 scpi_cmd_t response;
188 int power_state, cpu, cluster, rc = -1;
189
190 /*
191 * Extract CPU and cluster membership of the given MPIDR. SCPI caters
192 * for only up to 0xf clusters, and 8 CPUs per cluster
193 */
194 #if ARM_PLAT_MT
195 /*
196 * The current SCPI driver only caters for single-threaded platforms.
197 * Hence we ignore the thread ID (which is always 0) for such platforms.
198 */
199 cpu = (mpidr >> MPIDR_AFF1_SHIFT) & MPIDR_AFFLVL_MASK;
200 cluster = (mpidr >> MPIDR_AFF2_SHIFT) & MPIDR_AFFLVL_MASK;
201 #else
202 cpu = mpidr & MPIDR_AFFLVL_MASK;
203 cluster = (mpidr >> MPIDR_AFF1_SHIFT) & MPIDR_AFFLVL_MASK;
204 #endif /* ARM_PLAT_MT */
205 if (cpu >= 8 || cluster >= 0xf)
206 return -1;
207
208 scpi_secure_message_start();
209
210 /* Populate request headers */
211 zeromem(SCPI_CMD_HEADER_AP_TO_SCP, sizeof(*cmd));
212 cmd = SCPI_CMD_HEADER_AP_TO_SCP;
213 cmd->id = SCPI_CMD_GET_CSS_POWER_STATE;
214
215 /*
216 * Send message and wait for SCP's response
217 */
218 scpi_secure_message_send(0);
219 if (scpi_secure_message_receive(&response) != 0)
220 goto exit;
221
222 if (response.status != SCP_OK)
223 goto exit;
224
225 /* Validate SCP response */
226 if (!CHECK_RESPONSE(response, cluster))
227 goto exit;
228
229 /* Extract power states for required cluster */
230 power_state = *(((uint16_t *) SCPI_RES_PAYLOAD_SCP_TO_AP) + cluster);
231 if (CLUSTER_ID(power_state) != cluster)
232 goto exit;
233
234 /* Update power state via pointers */
235 if (cluster_state_p)
236 *cluster_state_p = CLUSTER_POWER_STATE(power_state);
237 if (cpu_state_p)
238 *cpu_state_p = CPU_POWER_STATE(power_state);
239 rc = 0;
240
241 exit:
242 scpi_secure_message_end();
243 return rc;
244 }
245
scpi_sys_power_state(scpi_system_state_t system_state)246 uint32_t scpi_sys_power_state(scpi_system_state_t system_state)
247 {
248 scpi_cmd_t *cmd;
249 uint8_t *payload_addr;
250 scpi_cmd_t response;
251
252 scpi_secure_message_start();
253
254 /* Populate the command header */
255 cmd = SCPI_CMD_HEADER_AP_TO_SCP;
256 cmd->id = SCPI_CMD_SYS_POWER_STATE;
257 cmd->set = 0;
258 cmd->sender = 0;
259 cmd->size = sizeof(*payload_addr);
260 /* Populate the command payload */
261 payload_addr = SCPI_CMD_PAYLOAD_AP_TO_SCP;
262 *payload_addr = system_state & 0xff;
263 scpi_secure_message_send(sizeof(*payload_addr));
264
265 /* If no response is received, fill in an error status */
266 if (scpi_secure_message_receive(&response) != 0)
267 response.status = SCP_E_TIMEOUT;
268
269 scpi_secure_message_end();
270
271 return response.status;
272 }
273