freebsd-dev/sys/dev/uart/uart_subr.c

270 lines
6.3 KiB
C

/*-
* Copyright (c) 2004 Marcel Moolenaar
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. 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.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``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 AUTHOR 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 <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/bus.h>
#include <machine/bus.h>
#include <machine/vmparam.h>
#include <dev/uart/uart.h>
#include <dev/uart/uart_cpu.h>
#define UART_TAG_BR 0
#define UART_TAG_CH 1
#define UART_TAG_DB 2
#define UART_TAG_DT 3
#define UART_TAG_IO 4
#define UART_TAG_MM 5
#define UART_TAG_PA 6
#define UART_TAG_RS 7
#define UART_TAG_SB 8
#define UART_TAG_XO 9
static bus_addr_t
uart_parse_addr(__const char **p)
{
return (strtoul(*p, (char**)(uintptr_t)p, 0));
}
static long
uart_parse_long(__const char **p)
{
return (strtol(*p, (char**)(uintptr_t)p, 0));
}
static int
uart_parse_parity(__const char **p)
{
if (!strncmp(*p, "even", 4)) {
*p += 4;
return UART_PARITY_EVEN;
}
if (!strncmp(*p, "mark", 4)) {
*p += 4;
return UART_PARITY_MARK;
}
if (!strncmp(*p, "none", 4)) {
*p += 4;
return UART_PARITY_NONE;
}
if (!strncmp(*p, "odd", 3)) {
*p += 3;
return UART_PARITY_ODD;
}
if (!strncmp(*p, "space", 5)) {
*p += 5;
return UART_PARITY_SPACE;
}
return (-1);
}
static int
uart_parse_tag(__const char **p)
{
int tag;
if ((*p)[0] == 'b' && (*p)[1] == 'r') {
tag = UART_TAG_BR;
goto out;
}
if ((*p)[0] == 'c' && (*p)[1] == 'h') {
tag = UART_TAG_CH;
goto out;
}
if ((*p)[0] == 'd' && (*p)[1] == 'b') {
tag = UART_TAG_DB;
goto out;
}
if ((*p)[0] == 'd' && (*p)[1] == 't') {
tag = UART_TAG_DT;
goto out;
}
if ((*p)[0] == 'i' && (*p)[1] == 'o') {
tag = UART_TAG_IO;
goto out;
}
if ((*p)[0] == 'm' && (*p)[1] == 'm') {
tag = UART_TAG_MM;
goto out;
}
if ((*p)[0] == 'p' && (*p)[1] == 'a') {
tag = UART_TAG_PA;
goto out;
}
if ((*p)[0] == 'r' && (*p)[1] == 's') {
tag = UART_TAG_RS;
goto out;
}
if ((*p)[0] == 's' && (*p)[1] == 'b') {
tag = UART_TAG_SB;
goto out;
}
if ((*p)[0] == 'x' && (*p)[1] == 'o') {
tag = UART_TAG_XO;
goto out;
}
return (-1);
out:
*p += 2;
if ((*p)[0] != ':')
return (-1);
(*p)++;
return (tag);
}
/*
* Parse a device specification. The specification is a list of attributes
* seperated by commas. Each attribute is a tag-value pair with the tag and
* value seperated by a colon. Supported tags are:
*
* br = Baudrate
* ch = Channel
* db = Data bits
* dt = Device type
* io = I/O port address
* mm = Memory mapped I/O address
* pa = Parity
* rs = Register shift
* sb = Stopbits
* xo = Device clock (xtal oscillator)
*
* The io and mm tags are mutually exclusive.
*/
int
uart_getenv(int devtype, struct uart_devinfo *di)
{
__const char *spec;
bus_addr_t addr = ~0U;
/*
* Check the environment variables "hw.uart.console" and
* "hw.uart.dbgport". These variables, when present, specify
* which UART port is to be used as serial console or debug
* port (resp).
*/
if (devtype == UART_DEV_CONSOLE)
spec = getenv("hw.uart.console");
else if (devtype == UART_DEV_DBGPORT)
spec = getenv("hw.uart.dbgport");
else
spec = NULL;
if (spec == NULL)
return (ENXIO);
/* Set defaults. */
di->ops = uart_ns8250_ops;
di->bas.chan = 0;
di->bas.regshft = 0;
di->bas.rclk = 0;
di->baudrate = 0;
di->databits = 8;
di->stopbits = 1;
di->parity = UART_PARITY_NONE;
/* Parse the attributes. */
while (1) {
switch (uart_parse_tag(&spec)) {
case UART_TAG_BR:
di->baudrate = uart_parse_long(&spec);
break;
case UART_TAG_CH:
di->bas.chan = uart_parse_long(&spec);
break;
case UART_TAG_DB:
di->databits = uart_parse_long(&spec);
break;
case UART_TAG_DT:
return (EINVAL); /* XXX not yet implemented. */
break;
case UART_TAG_IO:
di->bas.bst = uart_bus_space_io;
addr = uart_parse_addr(&spec);
break;
case UART_TAG_MM:
di->bas.bst = uart_bus_space_mem;
addr = uart_parse_addr(&spec);
break;
case UART_TAG_PA:
di->parity = uart_parse_parity(&spec);
break;
case UART_TAG_RS:
di->bas.regshft = uart_parse_long(&spec);
break;
case UART_TAG_SB:
di->stopbits = uart_parse_long(&spec);
break;
case UART_TAG_XO:
di->bas.rclk = uart_parse_long(&spec);
break;
default:
return (EINVAL);
}
if (*spec == '\0')
break;
if (*spec != ',')
return (EINVAL);
spec++;
}
/*
* If we still have an invalid address, the specification must be
* missing an I/O port or memory address. We don't like that.
*/
if (addr == ~0U)
return (EINVAL);
/*
* Accept only the well-known baudrates. Any invalid baudrate
* is silently replaced with a 0-valued baudrate. The 0 baudrate
* has special meaning. It means that we're not supposed to
* program the baudrate and simply communicate with whatever
* speed the hardware is currently programmed for.
*/
if (di->baudrate >= 19200) {
if (di->baudrate % 19200)
di->baudrate = 0;
} else if (di->baudrate >= 1200) {
if (di->baudrate % 1200)
di->baudrate = 0;
} else if (di->baudrate > 0) {
if (di->baudrate % 75)
di->baudrate = 0;
} else
di->baudrate = 0;
/* XXX the size of the mapping depends on the UART class. */
if (bus_space_map(di->bas.bst, addr, 8, 0, &di->bas.bsh) != 0)
return (EINVAL);
return (0);
}