Dhruva Gole | f499acc | 2024-11-14 18:57:21 +0530 | [diff] [blame] | 1 | /* |
| 2 | * Texas Instruments Mailbox Driver |
| 3 | * |
| 4 | * Copyright (C) 2024-2025 Texas Instruments Incorporated - https://www.ti.com/ |
| 5 | * |
| 6 | * SPDX-License-Identifier: BSD-3-Clause |
| 7 | */ |
| 8 | |
| 9 | #include <assert.h> |
| 10 | #include <errno.h> |
| 11 | #include <stdlib.h> |
| 12 | |
| 13 | #include <arch_helpers.h> |
| 14 | #include <common/debug.h> |
| 15 | #include <drivers/delay_timer.h> |
| 16 | #include <lib/mmio.h> |
| 17 | #include <lib/utils.h> |
| 18 | #include <lib/utils_def.h> |
| 19 | #include <ti_sci_transport.h> |
| 20 | |
| 21 | #include <platform_def.h> |
| 22 | |
| 23 | /* |
| 24 | * TI_MAILBOX_RX/TX_BASE and the MAILBOX_MAX_MESSAGE_SIZE values are expected |
| 25 | * to come from platform specific header file ie. platform_def.h |
| 26 | */ |
| 27 | |
| 28 | #define TI_MAILBOX_SYSC UL(0x10) |
| 29 | #define TI_MAILBOX_MSG UL(0x40) |
| 30 | #define TI_MAILBOX_FIFO_STATUS UL(0x80) |
| 31 | #define TI_MAILBOX_MSG_STATUS UL(0xc0) |
| 32 | |
| 33 | /* |
| 34 | * Function to poll for mailbox rx messages |
| 35 | * IRQ model is currently not in scope of this driver |
| 36 | */ |
| 37 | static int8_t ti_mailbox_poll_rx_status(void) |
| 38 | { |
| 39 | uint32_t num_messages_pending = 0U; |
| 40 | uint32_t retry_count = 100U; |
| 41 | |
| 42 | /* |
| 43 | * Keep polling till we get a message for 100 times |
| 44 | * with intervals of 10 milliseconds. |
| 45 | */ |
| 46 | while (num_messages_pending == 0U) { |
| 47 | num_messages_pending = mmio_read_32(TI_MAILBOX_RX_BASE + TI_MAILBOX_MSG_STATUS); |
| 48 | if (retry_count-- == 0U) { |
| 49 | return -ETIMEDOUT; |
| 50 | } |
| 51 | mdelay(10); |
| 52 | } |
| 53 | return 0; |
| 54 | } |
| 55 | |
| 56 | int ti_sci_transport_clear_rx_thread(enum ti_sci_transport_chan_id id) |
| 57 | { |
| 58 | /* MSG_STATUS tells us how many pending messages */ |
| 59 | uint32_t try_count = mmio_read_32(TI_MAILBOX_RX_BASE + TI_MAILBOX_MSG_STATUS); |
| 60 | |
| 61 | /* Run the loop till the status register is cleared */ |
| 62 | while (mmio_read_32(TI_MAILBOX_RX_BASE + TI_MAILBOX_MSG_STATUS) != 0U) { |
| 63 | WARN("Clearing message from mailbox FIFO\n"); |
| 64 | /* The act of reading the mailbox msg itself clears it */ |
| 65 | mmio_read_32(TI_MAILBOX_RX_BASE + TI_MAILBOX_MSG); |
| 66 | /* |
| 67 | * The try_count is kept independent of the value of the status register |
| 68 | * because if at any point a new mailbox message arrives while this loop |
| 69 | * is in progress, we would want to know that message arrived and not clear |
| 70 | * it. We would rather print the error than clear the message thus indicating |
| 71 | * that the system is probably in a bad/async state. |
| 72 | */ |
| 73 | if (!(try_count--)) { |
| 74 | ERROR("Could not clear all messages from mailbox FIFO\n"); |
| 75 | return -ETIMEDOUT; |
| 76 | } |
| 77 | } |
| 78 | |
| 79 | return 0; |
| 80 | } |
| 81 | |
| 82 | int ti_sci_transport_send(enum ti_sci_transport_chan_id id, const struct ti_sci_msg *msg) |
| 83 | { |
| 84 | uint32_t num_bytes; |
| 85 | void *dst_ptr = (void *)MAILBOX_TX_START_REGION; |
| 86 | |
| 87 | assert(msg != NULL); |
| 88 | |
| 89 | num_bytes = msg->len; |
| 90 | |
| 91 | /* |
| 92 | * Only a simple check because even if there's 1 pending message |
| 93 | * we will be in a bad state if we try to send another message |
| 94 | * due to the absence of any interrupt or buffer mgmt model. |
| 95 | */ |
| 96 | if (mmio_read_32(TI_MAILBOX_TX_BASE + TI_MAILBOX_FIFO_STATUS)) { |
| 97 | ERROR("Mailbox FIFO has pending messages!\n"); |
| 98 | return -EINVAL; |
| 99 | } |
| 100 | |
| 101 | if (num_bytes > MAILBOX_MAX_MESSAGE_SIZE) { |
| 102 | ERROR("message length %lu > max msg size\n", msg->len); |
| 103 | return -EINVAL; |
| 104 | } |
| 105 | |
| 106 | /* |
| 107 | * Move the buffer contents into the SRAM to be accessed by TIFS |
| 108 | */ |
| 109 | memmove(dst_ptr, msg->buf, num_bytes); |
| 110 | |
| 111 | mmio_write_32(TI_MAILBOX_TX_BASE + TI_MAILBOX_MSG, (uint64_t)(void *)dst_ptr); |
| 112 | |
| 113 | return 0; |
| 114 | } |
| 115 | |
| 116 | int ti_sci_transport_recv(enum ti_sci_transport_chan_id id, struct ti_sci_msg *msg) |
| 117 | { |
| 118 | uint32_t num_bytes; |
| 119 | uint64_t rcv_addr; |
| 120 | |
| 121 | assert(msg != NULL); |
| 122 | |
| 123 | num_bytes = msg->len; |
| 124 | |
| 125 | if (ti_mailbox_poll_rx_status() == -ETIMEDOUT) { |
| 126 | ERROR("Timeout waiting for receive\n"); |
| 127 | return -ETIMEDOUT; |
| 128 | } |
| 129 | |
| 130 | rcv_addr = mmio_read_32(TI_MAILBOX_RX_BASE + TI_MAILBOX_MSG); |
| 131 | |
| 132 | if (rcv_addr != MAILBOX_RX_START_REGION) { |
| 133 | ERROR("message address %lu is not valid\n", rcv_addr); |
| 134 | return -EINVAL; |
| 135 | } |
| 136 | |
| 137 | if (num_bytes > MAILBOX_MAX_MESSAGE_SIZE) { |
| 138 | ERROR("message length %lu > max msg size\n", msg->len); |
| 139 | return -EINVAL; |
| 140 | } |
| 141 | |
| 142 | memmove(msg->buf, (uint8_t *)(rcv_addr), num_bytes); |
| 143 | |
| 144 | return 0; |
| 145 | } |