blob: 65458a5d6dde8f9c86d1f588a466176a07d5d84b [file] [log] [blame]
Dhruva Golef499acc2024-11-14 18:57:21 +05301/*
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 */
37static 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
56int 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
82int 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
116int 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}