summaryrefslogtreecommitdiffstats
path: root/plat/brcm/common/brcm_scpi.c
blob: 0a703cb90f383cc9e16138f1975edb8b2c815128 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
/*
 * Copyright (c) 2019-2020, ARM Limited and Contributors. All rights reserved.
 *
 * SPDX-License-Identifier: BSD-3-Clause
 */

#include <assert.h>
#include <string.h>

#include <arch_helpers.h>
#include <common/debug.h>
#include <lib/utils.h>
#include <plat/common/platform.h>

#include <brcm_mhu.h>
#include <brcm_scpi.h>
#include <platform_def.h>

#define SCPI_SHARED_MEM_SCP_TO_AP	(PLAT_SCP_COM_SHARED_MEM_BASE)
#define SCPI_SHARED_MEM_AP_TO_SCP	(PLAT_SCP_COM_SHARED_MEM_BASE \
								 + 0x100)

/* Header and payload addresses for commands from AP to SCP */
#define SCPI_CMD_HEADER_AP_TO_SCP		\
	((scpi_cmd_t *) SCPI_SHARED_MEM_AP_TO_SCP)
#define SCPI_CMD_PAYLOAD_AP_TO_SCP		\
	((void *) (SCPI_SHARED_MEM_AP_TO_SCP + sizeof(scpi_cmd_t)))

/* Header and payload addresses for responses from SCP to AP */
#define SCPI_RES_HEADER_SCP_TO_AP \
	((scpi_cmd_t *) SCPI_SHARED_MEM_SCP_TO_AP)
#define SCPI_RES_PAYLOAD_SCP_TO_AP \
	((void *) (SCPI_SHARED_MEM_SCP_TO_AP + sizeof(scpi_cmd_t)))

/* ID of the MHU slot used for the SCPI protocol */
#define SCPI_MHU_SLOT_ID		0

static void scpi_secure_message_start(void)
{
	mhu_secure_message_start(SCPI_MHU_SLOT_ID);
}

static void scpi_secure_message_send(size_t payload_size)
{
	/*
	 * Ensure that any write to the SCPI payload area is seen by SCP before
	 * we write to the MHU register. If these 2 writes were reordered by
	 * the CPU then SCP would read stale payload data
	 */
	dmbst();

	mhu_secure_message_send(SCPI_MHU_SLOT_ID);
}

static void scpi_secure_message_receive(scpi_cmd_t *cmd)
{
	uint32_t mhu_status;

	assert(cmd != NULL);

	mhu_status = mhu_secure_message_wait();

	/* Expect an SCPI message, reject any other protocol */
	if (mhu_status != (1 << SCPI_MHU_SLOT_ID)) {
		ERROR("MHU: Unexpected protocol (MHU status: 0x%x)\n",
		      mhu_status);
		panic();
	}

	/*
	 * Ensure that any read to the SCPI payload area is done after reading
	 * the MHU register. If these 2 reads were reordered then the CPU would
	 * read invalid payload data
	 */
	dmbld();

	memcpy(cmd, (void *) SCPI_SHARED_MEM_SCP_TO_AP, sizeof(*cmd));
}

static void scpi_secure_message_end(void)
{
	mhu_secure_message_end(SCPI_MHU_SLOT_ID);
}

int scpi_wait_ready(void)
{
	scpi_cmd_t scpi_cmd;

	VERBOSE("Waiting for SCP_READY command...\n");

	/* Get a message from the SCP */
	scpi_secure_message_start();
	scpi_secure_message_receive(&scpi_cmd);
	scpi_secure_message_end();

	/* We are expecting 'SCP Ready', produce correct error if it's not */
	scpi_status_t status = SCP_OK;

	if (scpi_cmd.id != SCPI_CMD_SCP_READY) {
		ERROR("Unexpected SCP command: expected #%u, received #%u\n",
		      SCPI_CMD_SCP_READY, scpi_cmd.id);
		status = SCP_E_SUPPORT;
	} else if (scpi_cmd.size != 0) {
		ERROR("SCP_READY cmd has incorrect size: expected 0, got %u\n",
		      scpi_cmd.size);
		status = SCP_E_SIZE;
	}

	VERBOSE("Sending response for SCP_READY command\n");

	/*
	 * Send our response back to SCP.
	 * We are using the same SCPI header, just update the status field.
	 */
	scpi_cmd.status = status;
	scpi_secure_message_start();
	memcpy((void *) SCPI_SHARED_MEM_AP_TO_SCP, &scpi_cmd, sizeof(scpi_cmd));
	scpi_secure_message_send(0);
	scpi_secure_message_end();

	return status == SCP_OK ? 0 : -1;
}

void 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)
{
	scpi_cmd_t *cmd;
	uint32_t state = 0;
	uint32_t *payload_addr;

#if ARM_PLAT_MT
	/*
	 * The current SCPI driver only caters for single-threaded platforms.
	 * Hence we ignore the thread ID (which is always 0) for such platforms.
	 */
	state |= (mpidr >> MPIDR_AFF1_SHIFT) & 0x0f;	/* CPU ID */
	state |= ((mpidr >> MPIDR_AFF2_SHIFT) & 0x0f) << 4;	/* Cluster ID */
#else
	state |= mpidr & 0x0f;	/* CPU ID */
	state |= (mpidr & 0xf00) >> 4;	/* Cluster ID */
#endif /* ARM_PLAT_MT */

	state |= cpu_state << 8;
	state |= cluster_state << 12;
	state |= brcm_state << 16;

	scpi_secure_message_start();

	/* Populate the command header */
	cmd = SCPI_CMD_HEADER_AP_TO_SCP;
	cmd->id = SCPI_CMD_SET_POWER_STATE;
	cmd->set = SCPI_SET_NORMAL;
	cmd->sender = 0;
	cmd->size = sizeof(state);
	/* Populate the command payload */
	payload_addr = SCPI_CMD_PAYLOAD_AP_TO_SCP;
	*payload_addr = state;
	scpi_secure_message_send(sizeof(state));

	/*
	 * SCP does not reply to this command in order to avoid MHU interrupts
	 * from the sender, which could interfere with its power state request.
	 */
	scpi_secure_message_end();
}

/*
 * Query and obtain power state from SCP.
 *
 * In response to the query, SCP returns power states of all CPUs in all
 * clusters of the system. The returned response is then filtered based on the
 * supplied MPIDR. Power states of requested cluster and CPUs within are updated
 * via. supplied non-NULL pointer arguments.
 *
 * Returns 0 on success, or -1 on errors.
 */
int scpi_get_brcm_power_state(unsigned int mpidr, unsigned int *cpu_state_p,
		unsigned int *cluster_state_p)
{
	scpi_cmd_t *cmd;
	scpi_cmd_t response;
	int power_state, cpu, cluster, rc = -1;

	/*
	 * Extract CPU and cluster membership of the given MPIDR. SCPI caters
	 * for only up to 0xf clusters, and 8 CPUs per cluster
	 */
	cpu = mpidr & MPIDR_AFFLVL_MASK;
	cluster = (mpidr >> MPIDR_AFF1_SHIFT) & MPIDR_AFFLVL_MASK;
	if (cpu >= 8 || cluster >= 0xf)
		return -1;

	scpi_secure_message_start();

	/* Populate request headers */
	zeromem(SCPI_CMD_HEADER_AP_TO_SCP, sizeof(*cmd));
	cmd = SCPI_CMD_HEADER_AP_TO_SCP;
	cmd->id = SCPI_CMD_GET_POWER_STATE;

	/*
	 * Send message and wait for SCP's response
	 */
	scpi_secure_message_send(0);
	scpi_secure_message_receive(&response);

	if (response.status != SCP_OK)
		goto exit;

	/* Validate SCP response */
	if (!CHECK_RESPONSE(response, cluster))
		goto exit;

	/* Extract power states for required cluster */
	power_state = *(((uint16_t *) SCPI_RES_PAYLOAD_SCP_TO_AP) + cluster);
	if (CLUSTER_ID(power_state) != cluster)
		goto exit;

	/* Update power state via. pointers */
	if (cluster_state_p)
		*cluster_state_p = CLUSTER_POWER_STATE(power_state);
	if (cpu_state_p)
		*cpu_state_p = CPU_POWER_STATE(power_state);
	rc = 0;

exit:
	scpi_secure_message_end();
	return rc;
}

uint32_t scpi_sys_power_state(scpi_system_state_t system_state)
{
	scpi_cmd_t *cmd;
	uint8_t *payload_addr;

	scpi_secure_message_start();

	/* Populate the command header */
	cmd = SCPI_CMD_HEADER_AP_TO_SCP;
	cmd->id = SCPI_CMD_SYS_POWER_STATE;
	cmd->set = 0;
	cmd->sender = 0;
	cmd->size = sizeof(*payload_addr);
	/* Populate the command payload */
	payload_addr = SCPI_CMD_PAYLOAD_AP_TO_SCP;
	*payload_addr = system_state & 0xff;
	scpi_secure_message_send(sizeof(*payload_addr));

	scpi_secure_message_end();

	return SCP_OK;
}