diff options
Diffstat (limited to 'drivers/console/aarch32/console.S')
| -rw-r--r-- | drivers/console/aarch32/console.S | 114 |
1 files changed, 114 insertions, 0 deletions
diff --git a/drivers/console/aarch32/console.S b/drivers/console/aarch32/console.S new file mode 100644 index 00000000..29933452 --- /dev/null +++ b/drivers/console/aarch32/console.S @@ -0,0 +1,114 @@ +/* + * Copyright (c) 2016, ARM Limited and Contributors. All rights reserved. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions are met: + * + * Redistributions of source code must retain the above copyright notice, this + * list of conditions and the following disclaimer. + * + * Redistributions in binary form must reproduce the above copyright notice, + * this list of conditions and the following disclaimer in the documentation + * and/or other materials provided with the distribution. + * + * Neither the name of ARM nor the names of its contributors may be used + * to endorse or promote products derived from this software without specific + * prior written permission. + * + * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" + * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE + * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE + * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE + * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR + * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF + * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS + * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN + * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) + * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE + * POSSIBILITY OF SUCH DAMAGE. + */ +#include <asm_macros.S> + + .globl console_init + .globl console_uninit + .globl console_putc + .globl console_getc + + /* + * The console base is in the data section and not in .bss + * even though it is zero-init. In particular, this allows + * the console functions to start using this variable before + * the runtime memory is initialized for images which do not + * need to copy the .data section from ROM to RAM. + */ +.section .data.console_base ; .align 2 + console_base: .word 0x0 + + /* ----------------------------------------------- + * int console_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. It saves + * the console base to the data section. + * 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 - r3 + * ----------------------------------------------- + */ +func console_init + /* Check the input base address */ + cmp r0, #0 + beq init_fail + ldr r3, =console_base + str r0, [r3] + b console_core_init +init_fail: + bx lr +endfunc console_init + + /* ----------------------------------------------- + * void console_uninit(void) + * Function to finish the use of console driver. + * It sets the console_base as NULL so that any + * further invocation of `console_putc` or + * `console_getc` APIs would return error. + * ----------------------------------------------- + */ +func console_uninit + mov r0, #0 + ldr r3, =console_base + str r0, [r3] + bx lr +endfunc console_uninit + + /* --------------------------------------------- + * int console_putc(int c) + * 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 + * Out : return -1 on error else return character. + * Clobber list : r1, r2 + * --------------------------------------------- + */ +func console_putc + ldr r2, =console_base + ldr r1, [r2] + b console_core_putc +endfunc console_putc + + /* --------------------------------------------- + * int console_getc(void) + * Function to get a character from the console. + * It returns the character grabbed on success + * or -1 on error. + * Clobber list : r0, r1 + * --------------------------------------------- + */ +func console_getc + ldr r1, =console_base + ldr r0, [r1] + b console_core_getc +endfunc console_getc |