/* * Copyright (c) 2021, ARM Limited and Contributors. All rights reserved. * * SPDX-License-Identifier: BSD-3-Clause */ #include #include #include #include /* UART16550 Registers */ #define UARTTX 0x0 #define UARTRX 0x0 #define UARTDLL 0x0 #define UARTIER 0x1 #define UARTDLLM 0x1 #define UARTFCR 0x2 #define UARTLCR 0x3 #define UARTLSR 0x5 #define UARTMCR 0x4 /* FIFO Control Register bits */ #define UARTFCR_FIFOMD_16450 (0 << 6) #define UARTFCR_FIFOMD_16550 (1 << 6) #define UARTFCR_RXTRIG_1 (0 << 6) #define UARTFCR_RXTRIG_4 (1 << 6) #define UARTFCR_RXTRIG_8 (2 << 6) #define UARTFCR_RXTRIG_16 (3 << 6) #define UARTFCR_TXTRIG_1 (0 << 4) #define UARTFCR_TXTRIG_4 (1 << 4) #define UARTFCR_TXTRIG_8 (2 << 4) #define UARTFCR_TXTRIG_16 (3 << 4) #define UARTFCR_DMAEN (1 << 3) /* Enable DMA mode */ #define UARTFCR_TXCLR (1 << 2) /* Clear contents of Tx FIFO */ #define UARTFCR_RXCLR (1 << 1) /* Clear contents of Rx FIFO */ #define UARTFCR_FIFOEN (1 << 0) /* Enable the Tx/Rx FIFO */ #define UARTFCR_64FIFO (1 << 5) /* Line Control Register bits */ #define UARTLCR_DLAB (1 << 7) /* Divisor Latch Access */ #define UARTLCR_SETB (1 << 6) /* Set BREAK Condition */ #define UARTLCR_SETP (1 << 5) /* Set Parity to LCR[4] */ #define UARTLCR_EVEN (1 << 4) /* Even Parity Format */ #define UARTLCR_PAR (1 << 3) /* Parity */ #define UARTLCR_STOP (1 << 2) /* Stop Bit */ #define UARTLCR_WORDSZ_5 0 /* Word Length of 5 */ #define UARTLCR_WORDSZ_6 1 /* Word Length of 6 */ #define UARTLCR_WORDSZ_7 2 /* Word Length of 7 */ #define UARTLCR_WORDSZ_8 3 /* Word Length of 8 */ /* Line Status Register bits */ #define UARTLSR_RXFIFOEMT (1 << 9) /* Rx Fifo Empty */ #define UARTLSR_TXFIFOFULL (1 << 8) /* Tx Fifo Full */ #define UARTLSR_RXFIFOERR (1 << 7) /* Rx Fifo Error */ #define UARTLSR_TEMT (1 << 6) /* Tx Shift Register Empty */ #define UARTLSR_THRE (1 << 5) /* Tx Holding Register Empty */ #define UARTLSR_BRK (1 << 4) /* Break Condition Detected */ #define UARTLSR_FERR (1 << 3) /* Framing Error */ #define UARTLSR_PERR (1 << 3) /* Parity Error */ #define UARTLSR_OVRF (1 << 2) /* Rx Overrun Error */ #define UARTLSR_RDR (1 << 2) /* Rx Data Ready */ #define CONSOLE_T_16550_BASE CONSOLE_T_BASE /* * "core" functions are low-level implementations that don't require * writable memory and are thus safe to call in BL1 crash context. */ .globl nxp_console_16550_core_init .globl nxp_console_16550_core_putc .globl nxp_console_16550_core_getc .globl nxp_console_16550_core_flush .globl console_16550_putc .globl console_16550_getc .globl console_16550_flush /* ----------------------------------------------- * int nxp_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: 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 nxp_console_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 nxp_console_16550_core_init .globl nxp_console_16550_register /* ----------------------------------------------- * int nxp_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 w1 (UART clock) is 0, initialisation will be * skipped, relying on previous code to have done * this already. w2 is ignored then as well. * In: x0 - UART register base address * w1 - UART clock in Hz * w2 - Baud rate (ignored if w1 is 0) * x3 - pointer to empty console_t struct * Out: return 1 on success, 0 on error * Clobber list : x0, x1, x2, x6, x7, x14 * ----------------------------------------------- */ func nxp_console_16550_register mov x7, x30 mov x6, x3 cbz x6, register_fail str x0, [x6, #CONSOLE_T_16550_BASE] /* A clock rate of zero means to skip the initialisation. */ cbz w1, register_16550 bl nxp_console_16550_core_init cbz x0, register_fail register_16550: mov x0, x6 mov x30, x7 finish_console_register 16550 putc=1, getc=ENABLE_CONSOLE_GETC, flush=1 register_fail: ret x7 endfunc nxp_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 : w0 - character to be printed * x1 - console base address * Out : return -1 on error else return character. * Clobber list : x2 * -------------------------------------------------------- */ func nxp_console_16550_core_putc #if ENABLE_ASSERTIONS cmp x1, #0 ASM_ASSERT(ne) #endif /* ENABLE_ASSERTIONS */ /* Prepend '\r' to '\n' */ cmp w0, #'\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, #'\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 nxp_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 : w0 - character to be printed * x1 - pointer to console_t structure * Out : return -1 on error else return character. * Clobber list : x2 * -------------------------------------------------------- */ func console_16550_putc #if ENABLE_ASSERTIONS cmp x1, #0 ASM_ASSERT(ne) #endif /* ENABLE_ASSERTIONS */ ldr x1, [x1, #CONSOLE_T_16550_BASE] b nxp_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 : x0 - console base address * Out : w0 - character if available, else -1 * Clobber list : x0, x1 * --------------------------------------------- */ func nxp_console_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 nxp_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 : x0 - pointer to console_t structure * Out : w0 - character if available, else -1 * Clobber list : x0, x1 * --------------------------------------------- */ func console_16550_getc #if ENABLE_ASSERTIONS cmp x1, #0 ASM_ASSERT(ne) #endif /* ENABLE_ASSERTIONS */ ldr x0, [x0, #CONSOLE_T_16550_BASE] b nxp_console_16550_core_getc endfunc console_16550_getc /* --------------------------------------------- * int console_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 : return -1 on error else return 0. * Clobber list : x0, x1 * --------------------------------------------- */ func nxp_console_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_THRE) cmp w1, #(UARTLSR_THRE) b.ne 1b mov w0, #0 ret endfunc nxp_console_16550_core_flush /* --------------------------------------------- * int console_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 : return -1 on error else return 0. * Clobber list : x0, x1 * --------------------------------------------- */ func console_16550_flush #if ENABLE_ASSERTIONS cmp x0, #0 ASM_ASSERT(ne) #endif /* ENABLE_ASSERTIONS */ ldr x0, [x0, #CONSOLE_T_16550_BASE] b nxp_console_16550_core_flush endfunc console_16550_flush