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Heiko Stuebner73c37122019-03-07 10:26:19 +01001/*
2 * Copyright (c) 2015-2018, ARM Limited and Contributors. All rights reserved.
3 *
4 * SPDX-License-Identifier: BSD-3-Clause
5 */
6
7#include <arch.h>
8#include <asm_macros.S>
9#include <assert_macros.S>
10#include <console_macros.S>
11#include <drivers/ti/uart/uart_16550.h>
12
13 /*
14 * "core" functions are low-level implementations that don't require
15 * writable memory and are thus safe to call in BL1 crash context.
16 */
17 .globl console_16550_core_init
18 .globl console_16550_core_putc
19 .globl console_16550_core_getc
20 .globl console_16550_core_flush
21
22 .globl console_16550_putc
23 .globl console_16550_getc
24 .globl console_16550_flush
25
26 /* -----------------------------------------------
27 * int console_16550_core_init(uintptr_t base_addr,
28 * unsigned int uart_clk, unsigned int baud_rate)
29 * Function to initialize the console without a
30 * C Runtime to print debug information. This
31 * function will be accessed by console_init and
32 * crash reporting.
33 * In: r0 - console base address
34 * r1 - Uart clock in Hz
35 * r2 - Baud rate
36 * Out: return 1 on success, 0 on error
37 * Clobber list : r1, r2, r3
38 * -----------------------------------------------
39 */
40func console_16550_core_init
41 /* Check the input base address */
42 cmp r0, #0
43 beq init_fail
44 /* Check baud rate and uart clock for sanity */
45 cmp r1, #0
46 beq init_fail
47 cmp r2, #0
48 beq init_fail
49
50 /* Program the baudrate */
51 /* Divisor = Uart clock / (16 * baudrate) */
52 lsl r2, r2, #4
53 udiv r2, r1, r2
54 and r1, r2, #0xff /* w1 = DLL */
55 lsr r2, r2, #8
56 and r2, r2, #0xff /* w2 = DLLM */
57 ldr r3, [r0, #UARTLCR]
58 orr r3, r3, #UARTLCR_DLAB
59 str r3, [r0, #UARTLCR] /* enable DLL, DLLM programming */
60 str r1, [r0, #UARTDLL] /* program DLL */
61 str r2, [r0, #UARTDLLM] /* program DLLM */
62 mov r2, #~UARTLCR_DLAB
63 and r3, r3, r2
64 str r3, [r0, #UARTLCR] /* disable DLL, DLLM programming */
65
66 /* 8n1 */
67 mov r3, #3
68 str r3, [r0, #UARTLCR]
69 /* no interrupt */
70 mov r3, #0
71 str r3, [r0, #UARTIER]
72#ifdef TI_16550_MDR_QUIRK
73 /* UART must be enabled on some platforms via the MDR register */
74 str r3, [r0, #UARTMDR1]
75#endif /* TI_16550_MDR_QUIRK */
76 /* enable fifo, DMA */
77 mov r3, #(UARTFCR_FIFOEN | UARTFCR_DMAEN)
78 str r3, [r0, #UARTFCR]
79 /* DTR + RTS */
80 mov r3, #3
81 str r3, [r0, #UARTMCR]
82 mov r0, #1
83 bx lr
84init_fail:
85 mov r0, #0
86 bx lr
87endfunc console_16550_core_init
88
89 .globl console_16550_register
90
91 /* -------------------------------------------------------
Andre Przywara40497792019-12-12 12:00:15 +000092 * int console_16550_register(uintptr_t baseaddr,
Heiko Stuebner73c37122019-03-07 10:26:19 +010093 * uint32_t clock, uint32_t baud,
Andre Przywara40497792019-12-12 12:00:15 +000094 * console_16550_t *console);
95 * Function to initialize and register a new 16550
Heiko Stuebner73c37122019-03-07 10:26:19 +010096 * console. Storage passed in for the console struct
97 * *must* be persistent (i.e. not from the stack).
Andre Przywara40497792019-12-12 12:00:15 +000098 * If r1 (UART clock) is 0, initialisation will be
99 * skipped, relying on previous code to have done
100 * this already. r2 is ignored then as well.
Heiko Stuebner73c37122019-03-07 10:26:19 +0100101 * In: r0 - UART register base address
102 * r1 - UART clock in Hz
Andre Przywara40497792019-12-12 12:00:15 +0000103 * r2 - Baud rate (ignored if r1 is 0)
104 * r3 - pointer to empty console_16550_t struct
Heiko Stuebner73c37122019-03-07 10:26:19 +0100105 * Out: return 1 on success, 0 on error
106 * Clobber list : r0, r1, r2
107 * -------------------------------------------------------
108 */
109func console_16550_register
110 push {r4, lr}
111 mov r4, r3
112 cmp r4, #0
113 beq register_fail
114 str r0, [r4, #CONSOLE_T_16550_BASE]
115
Andre Przywara40497792019-12-12 12:00:15 +0000116 /* A clock rate of zero means to skip the initialisation. */
117 cmp r1, #0
118 beq register_16550
119
Heiko Stuebner73c37122019-03-07 10:26:19 +0100120 bl console_16550_core_init
121 cmp r0, #0
122 beq register_fail
123
Andre Przywara40497792019-12-12 12:00:15 +0000124register_16550:
Heiko Stuebner73c37122019-03-07 10:26:19 +0100125 mov r0, r4
126 pop {r4, lr}
127 finish_console_register 16550 putc=1, getc=1, flush=1
128
129register_fail:
130 pop {r4, pc}
131endfunc console_16550_register
132
133 /* --------------------------------------------------------
134 * int console_16550_core_putc(int c, uintptr_t base_addr)
135 * Function to output a character over the console. It
136 * returns the character printed on success or -1 on error.
137 * In : r0 - character to be printed
138 * r1 - console base address
139 * Out : return -1 on error else return character.
140 * Clobber list : r2
141 * --------------------------------------------------------
142 */
143func console_16550_core_putc
144#if ENABLE_ASSERTIONS
145 cmp r1, #0
146 ASM_ASSERT(ne)
147#endif /* ENABLE_ASSERTIONS */
148
149 /* Prepend '\r' to '\n' */
150 cmp r0, #0xA
151 bne 2f
152 /* Check if the transmit FIFO is full */
1531: ldr r2, [r1, #UARTLSR]
154 and r2, r2, #(UARTLSR_TEMT | UARTLSR_THRE)
155 cmp r2, #(UARTLSR_TEMT | UARTLSR_THRE)
156 bne 1b
157 mov r2, #0xD /* '\r' */
158 str r2, [r1, #UARTTX]
159
160 /* Check if the transmit FIFO is full */
1612: ldr r2, [r1, #UARTLSR]
162 and r2, r2, #(UARTLSR_TEMT | UARTLSR_THRE)
163 cmp r2, #(UARTLSR_TEMT | UARTLSR_THRE)
164 bne 2b
165 str r0, [r1, #UARTTX]
166 bx lr
167endfunc console_16550_core_putc
168
169 /* --------------------------------------------------------
170 * int console_16550_putc(int c, console_16550_t *console)
171 * Function to output a character over the console. It
172 * returns the character printed on success or -1 on error.
173 * In : r0 - character to be printed
174 * r1 - pointer to console_t structure
175 * Out : return -1 on error else return character.
176 * Clobber list : r2
177 * --------------------------------------------------------
178 */
179func console_16550_putc
180#if ENABLE_ASSERTIONS
181 cmp r1, #0
182 ASM_ASSERT(ne)
183#endif /* ENABLE_ASSERTIONS */
184 ldr r1, [r1, #CONSOLE_T_16550_BASE]
185 b console_16550_core_putc
186endfunc console_16550_putc
187
188 /* ---------------------------------------------
189 * int console_16550_core_getc(uintptr_t base_addr)
190 * Function to get a character from the console.
191 * It returns the character grabbed on success
192 * or -1 on if no character is available.
193 * In : r0 - console base address
194 * Clobber list : r0, r1
195 * ---------------------------------------------
196 */
197func console_16550_core_getc
198#if ENABLE_ASSERTIONS
199 cmp r0, #0
200 ASM_ASSERT(ne)
201#endif /* ENABLE_ASSERTIONS */
202
203 /* Check if the receive FIFO is empty */
2041: ldr r1, [r0, #UARTLSR]
205 tst r1, #UARTLSR_RDR_BIT
206 beq no_char
207 ldr r1, [r0, #UARTRX]
208 mov r0, r1
209 bx lr
210no_char:
211 mov r0, #ERROR_NO_PENDING_CHAR
212 bx lr
213endfunc console_16550_core_getc
214
215 /* ---------------------------------------------
216 * int console_16550_getc(console_16550_t *console)
217 * Function to get a character from the console.
218 * It returns the character grabbed on success
219 * or -1 on if no character is available.
220 * In : r0 - pointer to console_t stucture
221 * Out : r0 - character if available, else -1
222 * Clobber list : r0, r1
223 * ---------------------------------------------
224 */
225func console_16550_getc
226#if ENABLE_ASSERTIONS
227 cmp r0, #0
228 ASM_ASSERT(ne)
229#endif /* ENABLE_ASSERTIONS */
230 ldr r0, [r0, #CONSOLE_T_16550_BASE]
231 b console_16550_core_getc
232endfunc console_16550_getc
233
234 /* ---------------------------------------------
235 * int console_16550_core_flush(uintptr_t base_addr)
236 * Function to force a write of all buffered
237 * data that hasn't been output.
238 * In : r0 - console base address
239 * Out : return -1 on error else return 0.
240 * Clobber list : r0, r1
241 * ---------------------------------------------
242 */
243func console_16550_core_flush
244#if ENABLE_ASSERTIONS
245 cmp r0, #0
246 ASM_ASSERT(ne)
247#endif /* ENABLE_ASSERTIONS */
248
249 /* Loop until the transmit FIFO is empty */
2501: ldr r1, [r0, #UARTLSR]
251 and r1, r1, #(UARTLSR_TEMT | UARTLSR_THRE)
252 cmp r1, #(UARTLSR_TEMT | UARTLSR_THRE)
253 bne 1b
254
255 mov r0, #0
256 bx lr
257endfunc console_16550_core_flush
258
259 /* ---------------------------------------------
260 * int console_16550_flush(console_pl011_t *console)
261 * Function to force a write of all buffered
262 * data that hasn't been output.
263 * In : r0 - pointer to console_t structure
264 * Out : return -1 on error else return 0.
265 * Clobber list : r0, r1
266 * ---------------------------------------------
267 */
268func console_16550_flush
269#if ENABLE_ASSERTIONS
270 cmp r0, #0
271 ASM_ASSERT(ne)
272#endif /* ENABLE_ASSERTIONS */
273 ldr r0, [r0, #CONSOLE_T_16550_BASE]
274 b console_16550_core_flush
275endfunc console_16550_flush