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/*
* Copyright (c) 2022, Arm Limited. All rights reserved.
*
* SPDX-License-Identifier: BSD-3-Clause
*/
#include <assert.h>
#include <stddef.h>
#include <stdint.h>
#include <string.h>
#include <drivers/arm/mhu.h>
#include "mhu_v2_x.h"
#define MHU_NOTIFY_VALUE (1234u)
/*
* MHU devices for host:
* HSE: Host to Secure Enclave (sender device)
* SEH: Secure Enclave to Host (receiver device)
*/
struct mhu_v2_x_dev_t MHU1_HSE_DEV = {0, MHU_V2_X_SENDER_FRAME};
struct mhu_v2_x_dev_t MHU1_SEH_DEV = {0, MHU_V2_X_RECEIVER_FRAME};
static enum mhu_error_t error_mapping_to_mhu_error_t(enum mhu_v2_x_error_t err)
{
switch (err) {
case MHU_V_2_X_ERR_NONE:
return MHU_ERR_NONE;
case MHU_V_2_X_ERR_NOT_INIT:
return MHU_ERR_NOT_INIT;
case MHU_V_2_X_ERR_ALREADY_INIT:
return MHU_ERR_ALREADY_INIT;
case MHU_V_2_X_ERR_UNSUPPORTED_VERSION:
return MHU_ERR_UNSUPPORTED_VERSION;
case MHU_V_2_X_ERR_INVALID_ARG:
return MHU_ERR_INVALID_ARG;
case MHU_V_2_X_ERR_GENERAL:
return MHU_ERR_GENERAL;
default:
return MHU_ERR_GENERAL;
}
}
static enum mhu_v2_x_error_t signal_and_wait_for_clear(void)
{
enum mhu_v2_x_error_t err;
struct mhu_v2_x_dev_t *dev = &MHU1_HSE_DEV;
uint32_t val = MHU_NOTIFY_VALUE;
/* Using the last channel for notifications */
uint32_t channel_notify = mhu_v2_x_get_num_channel_implemented(dev) - 1;
err = mhu_v2_x_channel_send(dev, channel_notify, val);
if (err != MHU_V_2_X_ERR_NONE) {
return err;
}
do {
err = mhu_v2_x_channel_poll(dev, channel_notify, &val);
if (err != MHU_V_2_X_ERR_NONE) {
break;
}
} while (val != 0);
return err;
}
static enum mhu_v2_x_error_t wait_for_signal(void)
{
enum mhu_v2_x_error_t err;
struct mhu_v2_x_dev_t *dev = &MHU1_SEH_DEV;
uint32_t val = 0;
/* Using the last channel for notifications */
uint32_t channel_notify = mhu_v2_x_get_num_channel_implemented(dev) - 1;
do {
err = mhu_v2_x_channel_receive(dev, channel_notify, &val);
if (err != MHU_V_2_X_ERR_NONE) {
break;
}
} while (val != MHU_NOTIFY_VALUE);
return err;
}
static enum mhu_v2_x_error_t clear_and_wait_for_next_signal(void)
{
enum mhu_v2_x_error_t err;
struct mhu_v2_x_dev_t *dev = &MHU1_SEH_DEV;
uint32_t num_channels = mhu_v2_x_get_num_channel_implemented(dev);
uint32_t i;
/* Clear all channels */
for (i = 0; i < num_channels; ++i) {
err = mhu_v2_x_channel_clear(dev, i);
if (err != MHU_V_2_X_ERR_NONE) {
return err;
}
}
return wait_for_signal();
}
enum mhu_error_t mhu_init_sender(uintptr_t mhu_sender_base)
{
enum mhu_v2_x_error_t err;
assert(mhu_sender_base != (uintptr_t)NULL);
MHU1_HSE_DEV.base = mhu_sender_base;
err = mhu_v2_x_driver_init(&MHU1_HSE_DEV, MHU_REV_READ_FROM_HW);
return error_mapping_to_mhu_error_t(err);
}
enum mhu_error_t mhu_init_receiver(uintptr_t mhu_receiver_base)
{
enum mhu_v2_x_error_t err;
uint32_t num_channels, i;
assert(mhu_receiver_base != (uintptr_t)NULL);
MHU1_SEH_DEV.base = mhu_receiver_base;
err = mhu_v2_x_driver_init(&MHU1_SEH_DEV, MHU_REV_READ_FROM_HW);
if (err != MHU_V_2_X_ERR_NONE) {
return error_mapping_to_mhu_error_t(err);
}
num_channels = mhu_v2_x_get_num_channel_implemented(&MHU1_SEH_DEV);
/* Mask all channels except the notifying channel */
for (i = 0; i < (num_channels - 1); ++i) {
err = mhu_v2_x_channel_mask_set(&MHU1_SEH_DEV, i, UINT32_MAX);
if (err != MHU_V_2_X_ERR_NONE) {
return error_mapping_to_mhu_error_t(err);
}
}
/* The last channel is used for notifications */
err = mhu_v2_x_channel_mask_clear(
&MHU1_SEH_DEV, (num_channels - 1), UINT32_MAX);
return error_mapping_to_mhu_error_t(err);
}
/*
* Public function. See mhu.h
*
* The basic steps of transferring a message:
* 1. Initiate MHU transfer.
* 2. Send over the size of the payload on Channel 1. It is the very first
* 4 Bytes of the transfer. Continue with Channel 2.
* 3. Send over the payload, writing the channels one after the other
* (4 Bytes each). The last available channel is reserved for controlling
* the transfer.
* When the last channel is reached or no more data is left, STOP.
* 4. Notify the receiver using the last channel and wait for acknowledge.
* If there is still data to transfer, jump to step 3. Otherwise, proceed.
* 5. Close MHU transfer.
*
*/
enum mhu_error_t mhu_send_data(const uint8_t *send_buffer, size_t size)
{
enum mhu_v2_x_error_t err;
struct mhu_v2_x_dev_t *dev = &MHU1_HSE_DEV;
uint32_t num_channels = mhu_v2_x_get_num_channel_implemented(dev);
uint32_t chan = 0;
uint32_t i;
uint32_t *p;
/* For simplicity, require the send_buffer to be 4-byte aligned */
if ((uintptr_t)send_buffer & 0x3U) {
return MHU_ERR_INVALID_ARG;
}
err = mhu_v2_x_initiate_transfer(dev);
if (err != MHU_V_2_X_ERR_NONE) {
return error_mapping_to_mhu_error_t(err);
}
/* First send over the size of the actual message */
err = mhu_v2_x_channel_send(dev, chan, (uint32_t)size);
if (err != MHU_V_2_X_ERR_NONE) {
return error_mapping_to_mhu_error_t(err);
}
chan++;
p = (uint32_t *)send_buffer;
for (i = 0; i < size; i += 4) {
err = mhu_v2_x_channel_send(dev, chan, *p++);
if (err != MHU_V_2_X_ERR_NONE) {
return error_mapping_to_mhu_error_t(err);
}
if (++chan == (num_channels - 1)) {
err = signal_and_wait_for_clear();
if (err != MHU_V_2_X_ERR_NONE) {
return error_mapping_to_mhu_error_t(err);
}
chan = 0;
}
}
/* Signal the end of transfer.
* It's not required to send a signal when the message was
* perfectly-aligned (num_channels - 1 channels were used in the last
* round) preventing it from signaling twice at the end of transfer.
*/
if (chan != 0) {
err = signal_and_wait_for_clear();
if (err != MHU_V_2_X_ERR_NONE) {
return error_mapping_to_mhu_error_t(err);
}
}
err = mhu_v2_x_close_transfer(dev);
return error_mapping_to_mhu_error_t(err);
}
/*
* Public function. See mhu.h
*
* The basic steps of receiving a message:
* 1. Read the size of the payload from Channel 1. It is the very first
* 4 Bytes of the transfer. Continue with Channel 2.
* 2. Receive the payload, read the channels one after the other
* (4 Bytes each). The last available channel is reserved for controlling
* the transfer.
* When the last channel is reached clear all the channels
* (also sending an acknowledge on the last channel).
* 3. If there is still data to receive wait for a notification on the last
* channel and jump to step 2 as soon as it arrived. Otherwise, proceed.
* 4. End of transfer.
*
*/
enum mhu_error_t mhu_receive_data(uint8_t *receive_buffer, size_t *size)
{
enum mhu_v2_x_error_t err;
struct mhu_v2_x_dev_t *dev = &MHU1_SEH_DEV;
uint32_t num_channels = mhu_v2_x_get_num_channel_implemented(dev);
uint32_t chan = 0;
uint32_t message_len;
uint32_t i;
uint32_t *p;
/* For simplicity, require:
* - the receive_buffer to be 4-byte aligned,
* - the buffer size to be a multiple of 4.
*/
if (((uintptr_t)receive_buffer & 0x3U) || (*size & 0x3U)) {
return MHU_ERR_INVALID_ARG;
}
/* Busy wait for incoming reply */
err = wait_for_signal();
if (err != MHU_V_2_X_ERR_NONE) {
return error_mapping_to_mhu_error_t(err);
}
/* The first word is the length of the actual message */
err = mhu_v2_x_channel_receive(dev, chan, &message_len);
if (err != MHU_V_2_X_ERR_NONE) {
return error_mapping_to_mhu_error_t(err);
}
chan++;
if (message_len > *size) {
/* Message buffer too small */
*size = message_len;
return MHU_ERR_BUFFER_TOO_SMALL;
}
p = (uint32_t *)receive_buffer;
for (i = 0; i < message_len; i += 4) {
err = mhu_v2_x_channel_receive(dev, chan, p++);
if (err != MHU_V_2_X_ERR_NONE) {
return error_mapping_to_mhu_error_t(err);
}
/* Only wait for next transfer if there is still missing data */
if (++chan == (num_channels - 1) && (message_len - i) > 4) {
/* Busy wait for next transfer */
err = clear_and_wait_for_next_signal();
if (err != MHU_V_2_X_ERR_NONE) {
return error_mapping_to_mhu_error_t(err);
}
chan = 0;
}
}
/* Clear all channels */
for (i = 0; i < num_channels; ++i) {
err = mhu_v2_x_channel_clear(dev, i);
if (err != MHU_V_2_X_ERR_NONE) {
return error_mapping_to_mhu_error_t(err);
}
}
*size = message_len;
return MHU_ERR_NONE;
}
size_t mhu_get_max_message_size(void)
{
struct mhu_v2_x_dev_t *dev = &MHU1_SEH_DEV;
uint32_t num_channels = mhu_v2_x_get_num_channel_implemented(dev);
assert(num_channels != 0);
/*
* Returns only usable size of memory. As one channel is specifically
* used to inform about the size of payload, discard it from avialable
* memory size.
*/
return (num_channels - 1) * sizeof(uint32_t);
}