aboutsummaryrefslogtreecommitdiff
path: root/drivers/st/uart/aarch32/stm32_console.S
blob: 303d6bac7551fe8bd6f7b2fb349f76ef847d8f2e (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
/*
 * Copyright (c) 2018, ARM Limited and Contributors. All rights reserved.
 *
 * SPDX-License-Identifier: BSD-3-Clause
 */
#include <asm_macros.S>
#include <assert_macros.S>
#define USE_FINISH_CONSOLE_REG_2
#include <console_macros.S>
#include <stm32_console.h>
#include <stm32_uart_regs.h>

#define USART_TIMEOUT		0x1000

	/*
	 * "core" functions are low-level implementations that don't require
	 * writeable memory and are thus safe to call in BL1 crash context.
	 */
	.globl	console_stm32_core_init
	.globl	console_stm32_core_putc
	.globl	console_stm32_core_getc
	.globl	console_stm32_core_flush

	.globl	console_stm32_putc
	.globl	console_stm32_flush



	/* -----------------------------------------------------------------
	 * int console_core_init(uintptr_t base_addr,
	 *			 unsigned int uart_clk,
	 *			 unsigned int baud_rate)
	 *
	 * Function to initialize the console without a C Runtime to print
	 * debug information. This function will be accessed by console_init
	 * and crash reporting.
	 *
	 * In: r0 - console base address
	 *     r1 - Uart clock in Hz
	 *     r2 - Baud rate
	 * Out: return 1 on success else 0 on error
	 * Clobber list : r1, r2, r3
	 * -----------------------------------------------------------------
	 */
func console_stm32_core_init
	/* Check the input base address */
	cmp	r0, #0
	beq	core_init_fail
#if defined(IMAGE_BL2)
	/* Check baud rate and uart clock for sanity */
	cmp	r1, #0
	beq	core_init_fail
	cmp	r2, #0
	beq	core_init_fail
	/* Disable UART */
	ldr	r3, [r0, #USART_CR1]
	bic	r3, r3, #USART_CR1_UE
	str	r3, [r0, #USART_CR1]
	/* Configure UART */
	orr	r3, r3, #(USART_CR1_TE | USART_CR1_FIFOEN)
	str	r3, [r0, #USART_CR1]
	ldr	r3, [r0, #USART_CR2]
	bic	r3, r3, #USART_CR2_STOP
	str	r3, [r0, #USART_CR2]
	/* Divisor =  (Uart clock + (baudrate / 2)) / baudrate */
	lsl	r3, r2, #1
	add	r3, r1, r3
	udiv	r3, r3, r2
	str	r3, [r0, #USART_BRR]
	/* Enable UART */
	ldr	r3, [r0, #USART_CR1]
	orr	r3, r3, #USART_CR1_UE
	str	r3, [r0, #USART_CR1]
	/* Check TEACK bit */
	mov	r2, #USART_TIMEOUT
teack_loop:
	subs	r2, r2, #1
	beq	core_init_fail
	ldr	r3, [r0, #USART_ISR]
	tst	r3, #USART_ISR_TEACK
	beq	teack_loop
#endif /* IMAGE_BL2 */
	mov	r0, #1
	bx	lr
core_init_fail:
	mov	r0, #0
	bx	lr
endfunc console_stm32_core_init

	.globl console_stm32_register

	/* -------------------------------------------------------
	 * int console_stm32_register(uintptr_t baseaddr,
	 *     uint32_t clock, uint32_t baud,
	 *     struct console_stm32 *console);
	 * Function to initialize and register a new STM32
	 * console. Storage passed in for the console struct
	 * *must* be persistent (i.e. not from the stack).
	 * In: r0 - UART register base address
	 *     r1 - UART clock in Hz
	 *     r2 - Baud rate
	 *     r3 - pointer to empty console_stm32 struct
	 * Out: return 1 on success, 0 on error
	 * Clobber list : r0, r1, r2
	 * -------------------------------------------------------
	 */
func console_stm32_register
	push	{r4, lr}
	mov	r4, r3
	cmp	r4, #0
	beq	register_fail
	str	r0, [r4, #CONSOLE_T_STM32_BASE]

	bl console_stm32_core_init
	cmp	r0, #0
	beq	register_fail

	mov	r0, r4
	pop	{r4, lr}
	finish_console_register stm32 putc=1, getc=0, flush=1

register_fail:
	pop	{r4, pc}
endfunc console_stm32_register

	/* ---------------------------------------------------------------
	 * int console_core_putc(int c, uintptr_t base_addr)
	 *
	 * Function to output a character over the console. It returns the
	 * character printed on success or -1 on error.
	 *
	 * In : r0 - character to be printed
	 *      r1 - console base address
	 * Out : return -1 on error else return character.
	 * Clobber list : r2
	 * ---------------------------------------------------------------
	 */
func console_stm32_core_putc
	/* Check the input parameter */
	cmp	r1, #0
	beq	putc_error
	/* Prepend '\r' to '\n' */
	cmp	r0, #0xA
	bne	2f
1:
	/* Check Transmit Data Register Empty */
txe_loop_1:
	ldr	r2, [r1, #USART_ISR]
	tst	r2, #USART_ISR_TXE
	beq	txe_loop_1
	mov	r2, #0xD
	str	r2, [r1, #USART_TDR]
	/* Check transmit complete flag */
tc_loop_1:
	ldr	r2, [r1, #USART_ISR]
	tst	r2, #USART_ISR_TC
	beq	tc_loop_1
2:
	/* Check Transmit Data Register Empty */
txe_loop_2:
	ldr	r2, [r1, #USART_ISR]
	tst	r2, #USART_ISR_TXE
	beq	txe_loop_2
	str	r0, [r1, #USART_TDR]
	/* Check transmit complete flag */
tc_loop_2:
	ldr	r2, [r1, #USART_ISR]
	tst	r2, #USART_ISR_TC
	beq	tc_loop_2
	bx	lr
putc_error:
	mov	r0, #-1
	bx	lr
endfunc console_stm32_core_putc

	/* ------------------------------------------------------------
	 * int console_stm32_putc(int c, struct console_stm32 *console)
	 * Function to output a character over the console. It
	 * returns the character printed on success or -1 on error.
	 * In: r0 - character to be printed
	 *     r1 - pointer to console_t structure
	 * Out : return -1 on error else return character.
	 * Clobber list: r2
	 * ------------------------------------------------------------
	 */
func console_stm32_putc
#if ENABLE_ASSERTIONS
	cmp	r1, #0
	ASM_ASSERT(ne)
#endif /* ENABLE_ASSERTIONS */
	ldr	r1, [r1, #CONSOLE_T_STM32_BASE]
	b	console_stm32_core_putc
endfunc console_stm32_putc

	/* -----------------------------------------------------------
	 * int console_core_getc(uintptr_t base_addr)
	 *
	 * Function to get a character from the console.
	 * It returns the character grabbed on success or -1 on error.
	 *
	 * In : r0 - console base address
	 * Out : return -1.
	 * Clobber list : r0, r1
	 * -----------------------------------------------------------
	 */
func console_stm32_core_getc
	/* Not supported */
	mov	r0, #-1
	bx	lr
endfunc console_stm32_core_getc

	/* ---------------------------------------------------------------
	 * int console_core_flush(uintptr_t base_addr)
	 *
	 * Function to force a write of all buffered data that hasn't been
	 * output.
	 *
	 * In : r0 - console base address
	 * Out : return -1 on error else return 0.
	 * Clobber list : r0, r1
	 * ---------------------------------------------------------------
	 */
func console_stm32_core_flush
	cmp	r0, #0
	beq	flush_error
	/* Check Transmit Data Register Empty */
txe_loop_3:
	ldr	r1, [r0, #USART_ISR]
	tst	r1, #USART_ISR_TXE
	beq	txe_loop_3
	mov	r0, #0
	bx	lr
flush_error:
	mov	r0, #-1
	bx	lr
endfunc console_stm32_core_flush

	/* ------------------------------------------------------
	 * int console_stm32_flush(struct console_stm32 *console)
	 * Function to force a write of all buffered
	 * data that hasn't been output.
	 * In : r0 - pointer to console_t structure
	 * Out : return -1 on error else return 0.
	 * Clobber list: r0, r1
	 * ------------------------------------------------------
	 */
func console_stm32_flush
#if ENABLE_ASSERTIONS
	cmp	r0, #0
	ASM_ASSERT(ne)
#endif /* ENABLE_ASSERTIONS */
	ldr	r0, [r0, #CONSOLE_T_STM32_BASE]
	b	console_stm32_core_flush
endfunc console_stm32_flush