diff options
Diffstat (limited to 'qemu/roms/u-boot/drivers/serial/serial_arc.c')
| -rw-r--r-- | qemu/roms/u-boot/drivers/serial/serial_arc.c | 115 |
1 files changed, 115 insertions, 0 deletions
diff --git a/qemu/roms/u-boot/drivers/serial/serial_arc.c b/qemu/roms/u-boot/drivers/serial/serial_arc.c new file mode 100644 index 000000000..2ddbf32a5 --- /dev/null +++ b/qemu/roms/u-boot/drivers/serial/serial_arc.c @@ -0,0 +1,115 @@ +/* + * Copyright (C) 2013 Synopsys, Inc. (www.synopsys.com) + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + * + */ + +#include <common.h> +#include <serial.h> + +DECLARE_GLOBAL_DATA_PTR; + +struct arc_serial_regs { + unsigned int id0; + unsigned int id1; + unsigned int id2; + unsigned int id3; + unsigned int data; + unsigned int status; + unsigned int baudl; + unsigned int baudh; +}; + +/* Bit definitions of STATUS register */ +#define UART_RXEMPTY (1 << 5) +#define UART_OVERFLOW_ERR (1 << 1) +#define UART_TXEMPTY (1 << 7) + +struct arc_serial_regs *regs; + +static void arc_serial_setbrg(void) +{ + int arc_console_baud; + + if (!gd->baudrate) + gd->baudrate = CONFIG_BAUDRATE; + + arc_console_baud = gd->cpu_clk / (gd->baudrate * 4) - 1; + writeb(arc_console_baud & 0xff, ®s->baudl); + +#ifdef CONFIG_ARC + /* + * UART ISS(Instruction Set simulator) emulation has a subtle bug: + * A existing value of Baudh = 0 is used as a indication to startup + * it's internal state machine. + * Thus if baudh is set to 0, 2 times, it chokes. + * This happens with BAUD=115200 and the formaula above + * Until that is fixed, when running on ISS, we will set baudh to !0 + */ + if (gd->arch.running_on_hw) + writeb((arc_console_baud & 0xff00) >> 8, ®s->baudh); + else + writeb(1, ®s->baudh); +#else + writeb((arc_console_baud & 0xff00) >> 8, ®s->baudh); +#endif +} + +static int arc_serial_init(void) +{ + regs = (struct arc_serial_regs *)CONFIG_ARC_UART_BASE; + serial_setbrg(); + return 0; +} + +static void arc_serial_putc(const char c) +{ + if (c == '\n') + arc_serial_putc('\r'); + + while (!(readb(®s->status) & UART_TXEMPTY)) + ; + + writeb(c, ®s->data); +} + +static int arc_serial_tstc(void) +{ + return !(readb(®s->status) & UART_RXEMPTY); +} + +static int arc_serial_getc(void) +{ + while (!arc_serial_tstc()) + ; + + /* Check for overflow errors */ + if (readb(®s->status) & UART_OVERFLOW_ERR) + return 0; + + return readb(®s->data) & 0xFF; +} + +static struct serial_device arc_serial_drv = { + .name = "arc_serial", + .start = arc_serial_init, + .stop = NULL, + .setbrg = arc_serial_setbrg, + .putc = arc_serial_putc, + .puts = default_serial_puts, + .getc = arc_serial_getc, + .tstc = arc_serial_tstc, +}; + +void arc_serial_initialize(void) +{ + serial_register(&arc_serial_drv); +} + +__weak struct serial_device *default_serial_console(void) +{ + return &arc_serial_drv; +} |