diff options
Diffstat (limited to 'arch/mips/cpu/xburst/jz_serial.c')
-rw-r--r-- | arch/mips/cpu/xburst/jz_serial.c | 131 |
1 files changed, 131 insertions, 0 deletions
diff --git a/arch/mips/cpu/xburst/jz_serial.c b/arch/mips/cpu/xburst/jz_serial.c new file mode 100644 index 0000000..a147657 --- /dev/null +++ b/arch/mips/cpu/xburst/jz_serial.c @@ -0,0 +1,131 @@ +/* + * Jz4740 UART support + * Copyright (c) 2011 + * Qi Hardware, Xiangfu Liu <xiangfu@sharism.cc> + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License as + * published by the Free Software Foundation; either version 2 of + * the License, or (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, write to the Free Software + * Foundation, Inc., 59 Temple Place, Suite 330, Boston, + * MA 02111-1307 USA + */ + +#include <config.h> +#include <common.h> +#include <asm/io.h> +#include <asm/jz4740.h> +#include <serial.h> +#include <linux/compiler.h> + +/* + * serial_init - initialize a channel + * + * This routine initializes the number of data bits, parity + * and set the selected baud rate. Interrupts are disabled. + * Set the modem control signals if the option is selected. + * + * RETURNS: N/A + */ +struct jz4740_uart *uart = (struct jz4740_uart *)CONFIG_SYS_UART_BASE; + +static int jz_serial_init(void) +{ + /* Disable port interrupts while changing hardware */ + writeb(0, &uart->dlhr_ier); + + /* Disable UART unit function */ + writeb(~UART_FCR_UUE, &uart->iir_fcr); + + /* Set both receiver and transmitter in UART mode (not SIR) */ + writeb(~(SIRCR_RSIRE | SIRCR_TSIRE), &uart->isr); + + /* + * Set databits, stopbits and parity. + * (8-bit data, 1 stopbit, no parity) + */ + writeb(UART_LCR_WLEN_8 | UART_LCR_STOP_1, &uart->lcr); + + /* Set baud rate */ + serial_setbrg(); + + /* Enable UART unit, enable and clear FIFO */ + writeb(UART_FCR_UUE | UART_FCR_FE | UART_FCR_TFLS | UART_FCR_RFLS, + &uart->iir_fcr); + + return 0; +} + +static void jz_serial_setbrg(void) +{ + u32 baud_div, tmp; + + baud_div = CONFIG_SYS_EXTAL / 16 / CONFIG_BAUDRATE; + + tmp = readb(&uart->lcr); + tmp |= UART_LCR_DLAB; + writeb(tmp, &uart->lcr); + + writeb((baud_div >> 8) & 0xff, &uart->dlhr_ier); + writeb(baud_div & 0xff, &uart->rbr_thr_dllr); + + tmp &= ~UART_LCR_DLAB; + writeb(tmp, &uart->lcr); +} + +static int jz_serial_tstc(void) +{ + if (readb(&uart->lsr) & UART_LSR_DR) + return 1; + + return 0; +} + +static void jz_serial_putc(const char c) +{ + if (c == '\n') + serial_putc('\r'); + + /* Wait for fifo to shift out some bytes */ + while (!((readb(&uart->lsr) & (UART_LSR_TDRQ | UART_LSR_TEMT)) == 0x60)) + ; + + writeb((u8)c, &uart->rbr_thr_dllr); +} + +static int jz_serial_getc(void) +{ + while (!serial_tstc()) + ; + + return readb(&uart->rbr_thr_dllr); +} + +static struct serial_device jz_serial_drv = { + .name = "jz_serial", + .start = jz_serial_init, + .stop = NULL, + .setbrg = jz_serial_setbrg, + .putc = jz_serial_putc, + .puts = default_serial_puts, + .getc = jz_serial_getc, + .tstc = jz_serial_tstc, +}; + +void jz_serial_initialize(void) +{ + serial_register(&jz_serial_drv); +} + +__weak struct serial_device *default_serial_console(void) +{ + return &jz_serial_drv; +} |