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/*
* Copyright (c) 2014-2020, ARM Limited and Contributors. All rights reserved.
*
* SPDX-License-Identifier: BSD-3-Clause
*/
#include <assert.h>
#include <stdint.h>
#include <arch_helpers.h>
#include <common/debug.h>
#include <drivers/arm/css/css_mhu.h>
#include <drivers/arm/css/css_scp.h>
#include <drivers/arm/css/css_scpi.h>
#include <plat/common/platform.h>
#include <platform_def.h>
/* ID of the MHU slot used for the BOM protocol */
#define BOM_MHU_SLOT_ID 0
/* Boot commands sent from AP -> SCP */
#define BOOT_CMD_INFO 0x00
#define BOOT_CMD_DATA 0x01
/* BOM command header */
typedef struct {
uint32_t id : 8;
uint32_t reserved : 24;
} bom_cmd_t;
typedef struct {
uint32_t image_size;
uint32_t checksum;
} cmd_info_payload_t;
/*
* Unlike the SCPI protocol, the boot protocol uses the same memory region
* for both AP -> SCP and SCP -> AP transfers; define the address of this...
*/
#define BOM_SHARED_MEM PLAT_CSS_SCP_COM_SHARED_MEM_BASE
#define BOM_CMD_HEADER ((bom_cmd_t *) BOM_SHARED_MEM)
#define BOM_CMD_PAYLOAD ((void *) (BOM_SHARED_MEM + sizeof(bom_cmd_t)))
typedef struct {
/* Offset from the base address of the Trusted RAM */
uint32_t offset;
uint32_t block_size;
} cmd_data_payload_t;
/*
* All CSS platforms load SCP_BL2/SCP_BL2U just below BL2 (this is where BL31
* usually resides except when ARM_BL31_IN_DRAM is
* set). Ensure that SCP_BL2/SCP_BL2U do not overflow into shared RAM and
* the fw_config.
*/
CASSERT(SCP_BL2_LIMIT <= BL2_BASE, assert_scp_bl2_overwrite_bl2);
CASSERT(SCP_BL2U_LIMIT <= BL2_BASE, assert_scp_bl2u_overwrite_bl2);
CASSERT(SCP_BL2_BASE >= ARM_FW_CONFIG_LIMIT, assert_scp_bl2_overflow);
CASSERT(SCP_BL2U_BASE >= ARM_FW_CONFIG_LIMIT, assert_scp_bl2u_overflow);
static void scp_boot_message_start(void)
{
mhu_secure_message_start(BOM_MHU_SLOT_ID);
}
static void scp_boot_message_send(size_t payload_size)
{
/* Ensure that any write to the BOM 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();
/* Send command to SCP */
mhu_secure_message_send(BOM_MHU_SLOT_ID);
}
static uint32_t scp_boot_message_wait(size_t size)
{
uint32_t mhu_status;
mhu_status = mhu_secure_message_wait();
/* Expect an SCP Boot Protocol message, reject any other protocol */
if (mhu_status != (1 << BOM_MHU_SLOT_ID)) {
ERROR("MHU: Unexpected protocol (MHU status: 0x%x)\n",
mhu_status);
panic();
}
/* Ensure that any read to the BOM payload area is done after reading
* the MHU register. If these 2 reads were reordered then the CPU would
* read invalid payload data */
dmbld();
return *(uint32_t *) BOM_SHARED_MEM;
}
static void scp_boot_message_end(void)
{
mhu_secure_message_end(BOM_MHU_SLOT_ID);
}
int css_scp_boot_image_xfer(void *image, unsigned int image_size)
{
uint32_t response;
uint32_t checksum;
cmd_info_payload_t *cmd_info_payload;
cmd_data_payload_t *cmd_data_payload;
assert((uintptr_t) image == SCP_BL2_BASE);
if ((image_size == 0) || (image_size % 4 != 0)) {
ERROR("Invalid size for the SCP_BL2 image. Must be a multiple of "
"4 bytes and not zero (current size = 0x%x)\n",
image_size);
return -1;
}
/* Extract the checksum from the image */
checksum = *(uint32_t *) image;
image = (char *) image + sizeof(checksum);
image_size -= sizeof(checksum);
mhu_secure_init();
VERBOSE("Send info about the SCP_BL2 image to be transferred to SCP\n");
/*
* Send information about the SCP firmware image about to be transferred
* to SCP
*/
scp_boot_message_start();
BOM_CMD_HEADER->id = BOOT_CMD_INFO;
cmd_info_payload = BOM_CMD_PAYLOAD;
cmd_info_payload->image_size = image_size;
cmd_info_payload->checksum = checksum;
scp_boot_message_send(sizeof(*cmd_info_payload));
#if CSS_DETECT_PRE_1_7_0_SCP
{
const uint32_t deprecated_scp_nack_cmd = 0x404;
uint32_t mhu_status;
VERBOSE("Detecting SCP version incompatibility\n");
mhu_status = mhu_secure_message_wait();
if (mhu_status == deprecated_scp_nack_cmd) {
ERROR("Detected an incompatible version of the SCP firmware.\n");
ERROR("Only versions from v1.7.0 onwards are supported.\n");
ERROR("Please update the SCP firmware.\n");
return -1;
}
VERBOSE("SCP version looks OK\n");
}
#endif /* CSS_DETECT_PRE_1_7_0_SCP */
response = scp_boot_message_wait(sizeof(response));
scp_boot_message_end();
if (response != 0) {
ERROR("SCP BOOT_CMD_INFO returned error %u\n", response);
return -1;
}
VERBOSE("Transferring SCP_BL2 image to SCP\n");
/* Transfer SCP_BL2 image to SCP */
scp_boot_message_start();
BOM_CMD_HEADER->id = BOOT_CMD_DATA;
cmd_data_payload = BOM_CMD_PAYLOAD;
cmd_data_payload->offset = (uintptr_t) image - ARM_TRUSTED_SRAM_BASE;
cmd_data_payload->block_size = image_size;
scp_boot_message_send(sizeof(*cmd_data_payload));
response = scp_boot_message_wait(sizeof(response));
scp_boot_message_end();
if (response != 0) {
ERROR("SCP BOOT_CMD_DATA returned error %u\n", response);
return -1;
}
return 0;
}
int css_scp_boot_ready(void)
{
VERBOSE("Waiting for SCP to signal it is ready to go on\n");
/* Wait for SCP to signal it's ready */
return scpi_wait_ready();
}
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