1 /*
2 * Copyright (c) 2014-2017, ARM Limited and Contributors. All rights reserved.
3 *
4 * SPDX-License-Identifier: BSD-3-Clause
5 */
6
7 #include <arch_helpers.h>
8 #include <assert.h>
9 #include <css_def.h>
10 #include <debug.h>
11 #include <platform.h>
12 #include <stdint.h>
13 #include "../scpi/css_mhu.h"
14 #include "../scpi/css_scpi.h"
15
16 /* ID of the MHU slot used for the BOM protocol */
17 #define BOM_MHU_SLOT_ID 0
18
19 /* Boot commands sent from AP -> SCP */
20 #define BOOT_CMD_INFO 0x00
21 #define BOOT_CMD_DATA 0x01
22
23 /* BOM command header */
24 typedef struct {
25 uint32_t id : 8;
26 uint32_t reserved : 24;
27 } bom_cmd_t;
28
29 typedef struct {
30 uint32_t image_size;
31 uint32_t checksum;
32 } cmd_info_payload_t;
33
34 /*
35 * Unlike the SCPI protocol, the boot protocol uses the same memory region
36 * for both AP -> SCP and SCP -> AP transfers; define the address of this...
37 */
38 #define BOM_SHARED_MEM PLAT_CSS_SCP_COM_SHARED_MEM_BASE
39 #define BOM_CMD_HEADER ((bom_cmd_t *) BOM_SHARED_MEM)
40 #define BOM_CMD_PAYLOAD ((void *) (BOM_SHARED_MEM + sizeof(bom_cmd_t)))
41
42 typedef struct {
43 /* Offset from the base address of the Trusted RAM */
44 uint32_t offset;
45 uint32_t block_size;
46 } cmd_data_payload_t;
47
48 /*
49 * All CSS platforms load SCP_BL2/SCP_BL2U just below BL rw-data and above
50 * BL2/BL2U (this is where BL31 usually resides except when ARM_BL31_IN_DRAM is
51 * set. Ensure that SCP_BL2/SCP_BL2U do not overflow into BL1 rw-data nor
52 * BL2/BL2U.
53 */
54 CASSERT(SCP_BL2_LIMIT <= BL1_RW_BASE, assert_scp_bl2_overwrite_bl1);
55 CASSERT(SCP_BL2U_LIMIT <= BL1_RW_BASE, assert_scp_bl2u_overwrite_bl1);
56
57 CASSERT(SCP_BL2_BASE >= BL2_LIMIT, assert_scp_bl2_overwrite_bl2);
58 CASSERT(SCP_BL2U_BASE >= BL2U_LIMIT, assert_scp_bl2u_overwrite_bl2u);
59
scp_boot_message_start(void)60 static void scp_boot_message_start(void)
61 {
62 mhu_secure_message_start(BOM_MHU_SLOT_ID);
63 }
64
scp_boot_message_send(size_t payload_size)65 static void scp_boot_message_send(size_t payload_size)
66 {
67 /* Ensure that any write to the BOM payload area is seen by SCP before
68 * we write to the MHU register. If these 2 writes were reordered by
69 * the CPU then SCP would read stale payload data */
70 dmbst();
71
72 /* Send command to SCP */
73 mhu_secure_message_send(BOM_MHU_SLOT_ID);
74 }
75
scp_boot_message_wait(size_t size)76 static uint32_t scp_boot_message_wait(size_t size)
77 {
78 uint32_t mhu_status;
79
80 mhu_status = mhu_secure_message_wait();
81
82 /* Expect an SCP Boot Protocol message, reject any other protocol */
83 if (mhu_status != (1 << BOM_MHU_SLOT_ID)) {
84 ERROR("MHU: Unexpected protocol (MHU status: 0x%x)\n",
85 mhu_status);
86 panic();
87 }
88
89 /* Ensure that any read to the BOM payload area is done after reading
90 * the MHU register. If these 2 reads were reordered then the CPU would
91 * read invalid payload data */
92 dmbld();
93
94 return *(uint32_t *) BOM_SHARED_MEM;
95 }
96
scp_boot_message_end(void)97 static void scp_boot_message_end(void)
98 {
99 mhu_secure_message_end(BOM_MHU_SLOT_ID);
100 }
101
css_scp_boot_image_xfer(void * image,unsigned int image_size)102 int css_scp_boot_image_xfer(void *image, unsigned int image_size)
103 {
104 uint32_t response;
105 uint32_t checksum;
106 cmd_info_payload_t *cmd_info_payload;
107 cmd_data_payload_t *cmd_data_payload;
108
109 assert((uintptr_t) image == SCP_BL2_BASE);
110
111 if ((image_size == 0) || (image_size % 4 != 0)) {
112 ERROR("Invalid size for the SCP_BL2 image. Must be a multiple of "
113 "4 bytes and not zero (current size = 0x%x)\n",
114 image_size);
115 return -1;
116 }
117
118 /* Extract the checksum from the image */
119 checksum = *(uint32_t *) image;
120 image = (char *) image + sizeof(checksum);
121 image_size -= sizeof(checksum);
122
123 mhu_secure_init();
124
125 VERBOSE("Send info about the SCP_BL2 image to be transferred to SCP\n");
126
127 /*
128 * Send information about the SCP firmware image about to be transferred
129 * to SCP
130 */
131 scp_boot_message_start();
132
133 BOM_CMD_HEADER->id = BOOT_CMD_INFO;
134 cmd_info_payload = BOM_CMD_PAYLOAD;
135 cmd_info_payload->image_size = image_size;
136 cmd_info_payload->checksum = checksum;
137
138 scp_boot_message_send(sizeof(*cmd_info_payload));
139 #if CSS_DETECT_PRE_1_7_0_SCP
140 {
141 const uint32_t deprecated_scp_nack_cmd = 0x404;
142 uint32_t mhu_status;
143
144 VERBOSE("Detecting SCP version incompatibility\n");
145
146 mhu_status = mhu_secure_message_wait();
147 if (mhu_status == deprecated_scp_nack_cmd) {
148 ERROR("Detected an incompatible version of the SCP firmware.\n");
149 ERROR("Only versions from v1.7.0 onwards are supported.\n");
150 ERROR("Please update the SCP firmware.\n");
151 return -1;
152 }
153
154 VERBOSE("SCP version looks OK\n");
155 }
156 #endif /* CSS_DETECT_PRE_1_7_0_SCP */
157 response = scp_boot_message_wait(sizeof(response));
158 scp_boot_message_end();
159
160 if (response != 0) {
161 ERROR("SCP BOOT_CMD_INFO returned error %u\n", response);
162 return -1;
163 }
164
165 VERBOSE("Transferring SCP_BL2 image to SCP\n");
166
167 /* Transfer SCP_BL2 image to SCP */
168 scp_boot_message_start();
169
170 BOM_CMD_HEADER->id = BOOT_CMD_DATA;
171 cmd_data_payload = BOM_CMD_PAYLOAD;
172 cmd_data_payload->offset = (uintptr_t) image - ARM_TRUSTED_SRAM_BASE;
173 cmd_data_payload->block_size = image_size;
174
175 scp_boot_message_send(sizeof(*cmd_data_payload));
176 response = scp_boot_message_wait(sizeof(response));
177 scp_boot_message_end();
178
179 if (response != 0) {
180 ERROR("SCP BOOT_CMD_DATA returned error %u\n", response);
181 return -1;
182 }
183
184 return 0;
185 }
186
css_scp_boot_ready(void)187 int css_scp_boot_ready(void)
188 {
189 VERBOSE("Waiting for SCP to signal it is ready to go on\n");
190
191 /* Wait for SCP to signal it's ready */
192 return scpi_wait_ready();
193 }
194