/* * Copyright (c) 2018-2020, ARM Limited and Contributors. All rights reserved. * * SPDX-License-Identifier: BSD-3-Clause */ #include #include #include #include #include "ls_16550.h" /* * "core" functions are low-level implementations that don't require * writable memory and are thus safe to call in BL1 crash context. */ .globl console_ls_16550_core_init .globl console_ls_16550_core_putc .globl console_ls_16550_core_getc .globl console_ls_16550_putc .globl console_ls_16550_getc .globl console_ls_16550_flush /* ----------------------------------------------- * int console_ls_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: x0 - console base address * w1 - Uart clock in Hz * w2 - Baud rate * Out: return 1 on success, 0 on error * Clobber list : x1, x2, x3 * ----------------------------------------------- */ func console_ls_16550_core_init /* Check the input base address */ cbz x0, init_fail /* Check baud rate and uart clock for sanity */ cbz w1, init_fail cbz w2, init_fail /* Program the baudrate */ /* Divisor = Uart clock / (16 * baudrate) */ lsl w2, w2, #4 udiv w2, w1, w2 and w1, w2, #0xff /* w1 = DLL */ lsr w2, w2, #8 and w2, w2, #0xff /* w2 = DLLM */ ldrb w3, [x0, #UARTLCR] orr w3, w3, #UARTLCR_DLAB strb w3, [x0, #UARTLCR] /* enable DLL, DLLM programming */ strb w1, [x0, #UARTDLL] /* program DLL */ strb w2, [x0, #UARTDLLM] /* program DLLM */ mov w2, #~UARTLCR_DLAB and w3, w3, w2 strb w3, [x0, #UARTLCR] /* disable DLL, DLLM programming */ /* 8n1 */ mov w3, #3 strb w3, [x0, #UARTLCR] /* no interrupt */ mov w3, #0 strb w3, [x0, #UARTIER] /* enable fifo, DMA */ mov w3, #(UARTFCR_FIFOEN |UARTFCR_TXCLR | UARTFCR_RXCLR) strb w3, [x0, #UARTFCR] /* DTR + RTS */ mov w3, #3 str w3, [x0, #UARTMCR] mov w0, #1 ret init_fail: mov w0, #0 ret endfunc console_ls_16550_core_init .globl console_ls_16550_register /* ----------------------------------------------- * int console_ls_16550_register(console_t *console, * uintptr_t base, uint32_t clk, uint32_t baud) * 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). * In: x0 - UART register base address * w1 - UART clock in Hz * w2 - Baud rate * x3 - pointer to empty console_t struct * Out: return 1 on success, 0 on error * Clobber list : x0, x1, x2, x6, x7, x14 * ----------------------------------------------- */ func console_ls_16550_register mov x7, x30 mov x6, x3 cbz x6, register_fail str x0, [x6, #CONSOLE_T_BASE] bl console_ls_16550_core_init cbz x0, register_fail mov x0, x6 mov x30, x7 finish_console_register ls_16550 putc=1, getc=1, flush=1 register_fail: ret x7 endfunc console_ls_16550_register /* -------------------------------------------------------- * int console_ls_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 : w0 - character to be printed * x1 - console base address * Out : return -1 on error else return character. * Clobber list : x2 * -------------------------------------------------------- */ func console_ls_16550_core_putc #if ENABLE_ASSERTIONS cmp x1, #0 ASM_ASSERT(ne) #endif /* ENABLE_ASSERTIONS */ /* Prepend '\r' to '\n' */ cmp w0, #0xA //'\n' b.ne 2f /* Check if the transmit FIFO is full */ 1: ldrb w2, [x1, #UARTLSR] and w2, w2, #UARTLSR_THRE /* #(UARTLSR_TEMT | UARTLSR_THRE)*/ cmp w2, #(UARTLSR_THRE) b.ne 1b mov w2, #0xD /* '\r' */ strb w2, [x1, #UARTTX] ldrb w2, [x1, #UARTFCR] orr w2, w2, #UARTFCR_TXCLR /* Check if the transmit FIFO is full */ 2: ldrb w2, [x1, #UARTLSR] and w2, w2, #(UARTLSR_THRE) cmp w2, #(UARTLSR_THRE) b.ne 2b strb w0, [x1, #UARTTX] ret endfunc console_ls_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 : w0 - character to be printed * x1 - pointer to console_t structure * Out : return -1 on error else return character. * Clobber list : x2 * -------------------------------------------------------- */ func console_ls_16550_putc #if ENABLE_ASSERTIONS cmp x1, #0 ASM_ASSERT(ne) #endif /* ENABLE_ASSERTIONS */ ldr x1, [x1, #CONSOLE_T_BASE] b console_ls_16550_core_putc endfunc console_ls_16550_putc /* --------------------------------------------- * int console_ls_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 : x0 - console base address * Out : w0 - character if available, else -1 * Clobber list : x0, x1 * --------------------------------------------- */ func console_ls_16550_core_getc #if ENABLE_ASSERTIONS cmp x0, #0 ASM_ASSERT(ne) #endif /* ENABLE_ASSERTIONS */ /* Check if the receive FIFO is empty */ 1: ldrb w1, [x0, #UARTLSR] tbz w1, #UARTLSR_RDR, 1b ldrb w0, [x0, #UARTRX] ret no_char: mov w0, #ERROR_NO_PENDING_CHAR ret endfunc console_ls_16550_core_getc /* --------------------------------------------- * int console_ls_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 : x0 - pointer to console_t structure * Out : w0 - character if available, else -1 * Clobber list : x0, x1 * --------------------------------------------- */ func console_ls_16550_getc #if ENABLE_ASSERTIONS cmp x1, #0 ASM_ASSERT(ne) #endif /* ENABLE_ASSERTIONS */ ldr x0, [x0, #CONSOLE_T_BASE] b console_ls_16550_core_getc endfunc console_ls_16550_getc /* --------------------------------------------- * void console_ls_16550_core_flush(uintptr_t base_addr) * Function to force a write of all buffered * data that hasn't been output. * In : x0 - console base address * Out : void * Clobber list : x0, x1 * --------------------------------------------- */ func console_ls_16550_core_flush #if ENABLE_ASSERTIONS cmp x0, #0 ASM_ASSERT(ne) #endif /* ENABLE_ASSERTIONS */ /* Loop until the transmit FIFO is empty */ 1: ldrb w1, [x0, #UARTLSR] and w1, w1, #(UARTLSR_TEMT | UARTLSR_THRE) cmp w1, #(UARTLSR_TEMT | UARTLSR_THRE) b.ne 1b ret endfunc console_ls_16550_core_flush /* --------------------------------------------- * void console_ls_16550_flush(console_t *console) * Function to force a write of all buffered * data that hasn't been output. * In : x0 - pointer to console_t structure * Out : void * Clobber list : x0, x1 * --------------------------------------------- */ func console_ls_16550_flush #if ENABLE_ASSERTIONS cmp x0, #0 ASM_ASSERT(ne) #endif /* ENABLE_ASSERTIONS */ ldr x0, [x0, #CONSOLE_T_BASE] b console_ls_16550_core_flush endfunc console_ls_16550_flush