diff options
author | Soren Brinkmann <soren.brinkmann@xilinx.com> | 2016-03-06 20:14:51 -0800 |
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committer | Soren Brinkmann <soren.brinkmann@xilinx.com> | 2016-04-01 11:43:45 -0700 |
commit | b5e6d092947c2dc5be91a40f45860f02f4ea682d (patch) | |
tree | dc58070a23cfd0c14303241023bad15446399424 /drivers | |
parent | 4c51badfb52128a186e1ed3ae63b324d89a69fbd (diff) |
drivers: Add Cadence UART driver
Add a driver for the Cadence UART which is found in Xilinx Zynq SOCs.
Signed-off-by: Soren Brinkmann <soren.brinkmann@xilinx.com>
Diffstat (limited to 'drivers')
-rw-r--r-- | drivers/cadence/uart/cdns_console.S | 127 |
1 files changed, 127 insertions, 0 deletions
diff --git a/drivers/cadence/uart/cdns_console.S b/drivers/cadence/uart/cdns_console.S new file mode 100644 index 00000000..2c7960d8 --- /dev/null +++ b/drivers/cadence/uart/cdns_console.S @@ -0,0 +1,127 @@ +/* + * 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 <arch.h> +#include <asm_macros.S> +#include <cadence/cdns_uart.h> + + .globl console_core_init + .globl console_core_putc + .globl console_core_getc + + /* ----------------------------------------------- + * int console_core_init(unsigned long 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. + * We assume that the bootloader already set up + * the HW (baud, ...) and only enable the trans- + * mitter and receiver here. + * In: x0 - console base address + * w1 - Uart clock in Hz + * w2 - Baud rate + * Out: return 1 on success else 0 on error + * Clobber list : x1, x2, x3 + * ----------------------------------------------- + */ +func console_core_init + /* Check the input base address */ + cbz x0, core_init_fail + /* Check baud rate and uart clock for sanity */ + cbz w1, core_init_fail + cbz w2, core_init_fail + + /* RX/TX enabled & reset */ + mov w3, #(R_UART_CR_TX_EN | R_UART_CR_RX_EN | R_UART_CR_TXRST | R_UART_CR_RXRST) + str w3, [x0, #R_UART_CR] + + mov w0, #1 + ret +core_init_fail: + mov w0, wzr + ret +endfunc console_core_init + + /* -------------------------------------------------------- + * int console_core_putc(int c, unsigned long 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_core_putc + /* Check the input parameter */ + cbz x1, putc_error + /* Prepend '\r' to '\n' */ + cmp w0, #0xA + b.ne 2f +1: + /* Check if the transmit FIFO is full */ + ldr w2, [x1, #R_UART_SR] + tbnz w2, #UART_SR_INTR_TFUL_BIT, 1b + mov w2, #0xD + str w2, [x1, #R_UART_TX] +2: + /* Check if the transmit FIFO is full */ + ldr w2, [x1, #R_UART_SR] + tbnz w2, #UART_SR_INTR_TFUL_BIT, 2b + str w0, [x1, #R_UART_TX] + ret +putc_error: + mov w0, #-1 + ret +endfunc console_core_putc + + /* --------------------------------------------- + * int console_core_getc(unsigned long base_addr) + * Function to get a character from the console. + * It returns the character grabbed on success + * or -1 on error. + * In : x0 - console base address + * Clobber list : x0, x1 + * --------------------------------------------- + */ +func console_core_getc + cbz x0, getc_error +1: + /* Check if the receive FIFO is empty */ + ldr w1, [x0, #R_UART_SR] + tbnz w1, #UART_SR_INTR_REMPTY_BIT, 1b + ldr w1, [x0, #R_UART_RX] + mov w0, w1 + ret +getc_error: + mov w0, #-1 + ret +endfunc console_core_getc |