/* * Copyright (c) 2015-2020, ARM Limited and Contributors. All rights reserved. * * SPDX-License-Identifier: BSD-3-Clause */ #include #include #include #include #include /* * "core" functions are low-level implementations that don't require * writable memory and are thus safe to call in BL1 crash context. */ .globl console_16550_core_init .globl console_16550_core_putc .globl console_16550_core_getc .globl console_16550_core_flush .globl console_16550_putc .globl console_16550_getc .globl console_16550_flush /* ----------------------------------------------- * int console_16550_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, 0 on error * Clobber list : r1, r2, r3 * ----------------------------------------------- */ func console_16550_core_init /* Check the input base address */ cmp r0, #0 beq init_fail /* Check baud rate and uart clock for sanity */ cmp r1, #0 beq init_fail cmp r2, #0 beq init_fail /* Program the baudrate */ /* Divisor = Uart clock / (16 * baudrate) */ lsl r2, r2, #4 udiv r2, r1, r2 and r1, r2, #0xff /* w1 = DLL */ lsr r2, r2, #8 and r2, r2, #0xff /* w2 = DLLM */ ldr r3, [r0, #UARTLCR] orr r3, r3, #UARTLCR_DLAB str r3, [r0, #UARTLCR] /* enable DLL, DLLM programming */ str r1, [r0, #UARTDLL] /* program DLL */ str r2, [r0, #UARTDLLM] /* program DLLM */ mov r2, #~UARTLCR_DLAB and r3, r3, r2 str r3, [r0, #UARTLCR] /* disable DLL, DLLM programming */ /* 8n1 */ mov r3, #3 str r3, [r0, #UARTLCR] /* no interrupt */ mov r3, #0 str r3, [r0, #UARTIER] #ifdef TI_16550_MDR_QUIRK /* UART must be enabled on some platforms via the MDR register */ str r3, [r0, #UARTMDR1] #endif /* TI_16550_MDR_QUIRK */ /* enable fifo, DMA */ mov r3, #(UARTFCR_FIFOEN | UARTFCR_DMAEN) str r3, [r0, #UARTFCR] /* DTR + RTS */ mov r3, #3 str r3, [r0, #UARTMCR] mov r0, #1 bx lr init_fail: mov r0, #0 bx lr endfunc console_16550_core_init .globl console_16550_register /* ------------------------------------------------------- * int console_16550_register(uintptr_t baseaddr, * uint32_t clock, uint32_t baud, * console_t *console); * Function to initialize and register a new 16550 * console. Storage passed in for the console struct * *must* be persistent (i.e. not from the stack). * If r1 (UART clock) is 0, initialisation will be * skipped, relying on previous code to have done * this already. r2 is ignored then as well. * In: r0 - UART register base address * r1 - UART clock in Hz * r2 - Baud rate (ignored if r1 is 0) * r3 - pointer to empty console_t struct * Out: return 1 on success, 0 on error * Clobber list : r0, r1, r2 * ------------------------------------------------------- */ func console_16550_register push {r4, lr} mov r4, r3 cmp r4, #0 beq register_fail str r0, [r4, #CONSOLE_T_BASE] /* A clock rate of zero means to skip the initialisation. */ cmp r1, #0 beq register_16550 bl console_16550_core_init cmp r0, #0 beq register_fail register_16550: mov r0, r4 pop {r4, lr} finish_console_register 16550 putc=1, getc=1, flush=1 register_fail: pop {r4, pc} endfunc console_16550_register /* -------------------------------------------------------- * int console_16550_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_16550_core_putc #if ENABLE_ASSERTIONS cmp r1, #0 ASM_ASSERT(ne) #endif /* ENABLE_ASSERTIONS */ /* Prepend '\r' to '\n' */ cmp r0, #0xA bne 2f /* Check if the transmit FIFO is full */ 1: ldr r2, [r1, #UARTLSR] and r2, r2, #(UARTLSR_TEMT | UARTLSR_THRE) cmp r2, #(UARTLSR_TEMT | UARTLSR_THRE) bne 1b mov r2, #0xD /* '\r' */ str r2, [r1, #UARTTX] /* Check if the transmit FIFO is full */ 2: ldr r2, [r1, #UARTLSR] and r2, r2, #(UARTLSR_TEMT | UARTLSR_THRE) cmp r2, #(UARTLSR_TEMT | UARTLSR_THRE) bne 2b str r0, [r1, #UARTTX] bx lr endfunc console_16550_core_putc /* -------------------------------------------------------- * int console_16550_putc(int c, console_t *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_16550_putc #if ENABLE_ASSERTIONS cmp r1, #0 ASM_ASSERT(ne) #endif /* ENABLE_ASSERTIONS */ ldr r1, [r1, #CONSOLE_T_BASE] b console_16550_core_putc endfunc console_16550_putc /* --------------------------------------------- * int console_16550_core_getc(uintptr_t base_addr) * Function to get a character from the console. * It returns the character grabbed on success * or -1 on if no character is available. * In : r0 - console base address * Clobber list : r0, r1 * --------------------------------------------- */ func console_16550_core_getc #if ENABLE_ASSERTIONS cmp r0, #0 ASM_ASSERT(ne) #endif /* ENABLE_ASSERTIONS */ /* Check if the receive FIFO is empty */ 1: ldr r1, [r0, #UARTLSR] tst r1, #UARTLSR_RDR_BIT beq no_char ldr r1, [r0, #UARTRX] mov r0, r1 bx lr no_char: mov r0, #ERROR_NO_PENDING_CHAR bx lr endfunc console_16550_core_getc /* --------------------------------------------- * int console_16550_getc(console_t *console) * Function to get a character from the console. * It returns the character grabbed on success * or -1 on if no character is available. * In : r0 - pointer to console_t stucture * Out : r0 - character if available, else -1 * Clobber list : r0, r1 * --------------------------------------------- */ func console_16550_getc #if ENABLE_ASSERTIONS cmp r0, #0 ASM_ASSERT(ne) #endif /* ENABLE_ASSERTIONS */ ldr r0, [r0, #CONSOLE_T_BASE] b console_16550_core_getc endfunc console_16550_getc /* --------------------------------------------- * void console_16550_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 : void. * Clobber list : r0, r1 * --------------------------------------------- */ func console_16550_core_flush #if ENABLE_ASSERTIONS cmp r0, #0 ASM_ASSERT(ne) #endif /* ENABLE_ASSERTIONS */ /* Loop until the transmit FIFO is empty */ 1: ldr r1, [r0, #UARTLSR] and r1, r1, #(UARTLSR_TEMT | UARTLSR_THRE) cmp r1, #(UARTLSR_TEMT | UARTLSR_THRE) bne 1b bx lr endfunc console_16550_core_flush /* --------------------------------------------- * void console_16550_flush(console_t *console) * Function to force a write of all buffered * data that hasn't been output. * In : r0 - pointer to console_t structure * Out : void * Clobber list : r0, r1 * --------------------------------------------- */ func console_16550_flush #if ENABLE_ASSERTIONS cmp r0, #0 ASM_ASSERT(ne) #endif /* ENABLE_ASSERTIONS */ ldr r0, [r0, #CONSOLE_T_BASE] b console_16550_core_flush endfunc console_16550_flush