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[uart] Allow for the existence of non-16550 UARTs

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Remove the assumption that all platforms use a fixed number of 16550
UARTs identifiable by a simple numeric index.  Create an abstraction
allowing for dynamic instantiation and registration of any number of
arbitrary UART models.

The common case of the serial console on x86 uses a single fixed UART
specified at compile time.  Avoid unnecessarily dragging in the
dynamic instantiation code in this use case by allowing COMCONSOLE to
refer to a single static UART object representing the relevant port.

When selecting a UART by command-line argument (as used in the
"gdbstub serial <port>" command), allow the UART to be specified as
either a numeric index (to retain backwards compatiblity) or a
case-insensitive port name such as "COM2".

Signed-off-by: Michael Brown <mcb30@ipxe.org>
This commit is contained in:
Michael Brown
2025-06-17 14:28:18 +01:00
parent 60e167c00b
commit 6c8fb4b89d
15 changed files with 689 additions and 320 deletions
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1
src/Makefile
View File

@@ -94,6 +94,7 @@ SRCDIRS += drivers/infiniband/mlx_utils/mlx_lib/mlx_link_speed
SRCDIRS += drivers/infiniband/mlx_utils/mlx_lib/mlx_mtu
SRCDIRS += drivers/infiniband/mlx_nodnic/src
SRCDIRS += drivers/usb
SRCDIRS += drivers/uart
SRCDIRS += interface/pxe interface/efi interface/smbios
SRCDIRS += interface/bofm
SRCDIRS += interface/xen

58
src/arch/x86/core/x86_uart.c
View File

@@ -1,5 +1,5 @@
/*
* Copyright (C) 2014 Michael Brown <mbrown@fensystems.co.uk>.
* Copyright (C) 2025 Michael Brown <mbrown@fensystems.co.uk>.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License as
@@ -29,41 +29,45 @@ FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
*
*/
#include <errno.h>
#include <ipxe/uart.h>
#include <string.h>
#include <ipxe/serial.h>
#include <ipxe/ns16550.h>
/** UART port bases */
static uint16_t uart_base[] = {
[COM1] = 0x3f8,
[COM2] = 0x2f8,
[COM3] = 0x3e8,
[COM4] = 0x2e8,
};
/** Define a fixed ISA UART */
#define ISA_UART( NAME, BASE ) \
struct ns16550_uart NAME = { \
.uart = { \
.refcnt = REF_INIT ( ref_no_free ), \
.name = #NAME, \
.op = &ns16550_operations, \
}, \
.base = ( ( void * ) (BASE) ), \
}
/* Fixed ISA UARTs */
ISA_UART ( com1, COM1_BASE );
ISA_UART ( com2, COM2_BASE );
ISA_UART ( com3, COM3_BASE );
ISA_UART ( com4, COM4_BASE );
/**
* Select UART port
* Register fixed ISA UARTs
*
* @v uart UART
* @v port Port number, or 0 to disable
* @ret rc Return status code
*/
int uart_select ( struct uart *uart, unsigned int port ) {
int uart_register_fixed ( void ) {
static struct uart *ports[] = { COM1, COM2, COM3, COM4 };
unsigned int i;
int rc;
/* Set new UART base */
if ( port >= ( sizeof ( uart_base ) / sizeof ( uart_base[0] ) ) ) {
rc = -ENODEV;
goto err;
/* Register all fixed ISA UARTs */
for ( i = 0 ; i < ( sizeof ( ports ) / sizeof ( ports[0] ) ) ; i++ ) {
if ( ( rc = uart_register ( ports[i] ) ) != 0 ) {
DBGC ( ports[i], "UART could not register %s: %s\n",
ports[i]->name, strerror ( rc ) );
return rc;
}
}
uart->base = ( ( void * ) ( intptr_t ) uart_base[port] );
/* Check that UART exists */
if ( ( rc = uart_exists ( uart ) ) != 0 )
goto err;
return 0;
err:
uart->base = NULL;
return rc;
}

60
src/arch/x86/include/bits/ns16550.h Normal file
View File

@@ -0,0 +1,60 @@
#ifndef _BITS_NS16550_H
#define _BITS_NS16550_H
/** @file
*
* 16550-compatible UART
*
*/
FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
#include <stdint.h>
#include <ipxe/io.h>
/**
* Write to UART register
*
* @v ns16550 16550 UART
* @v address Register address
* @v data Data
*/
static inline __attribute__ (( always_inline )) void
ns16550_write ( struct ns16550_uart *ns16550, unsigned int address,
uint8_t data ) {
outb ( data, ( ns16550->base + address ) );
}
/**
* Read from UART register
*
* @v ns16550 16550 UART
* @v address Register address
* @ret data Data
*/
static inline __attribute__ (( always_inline )) uint8_t
ns16550_read ( struct ns16550_uart *ns16550, unsigned int address ) {
return inb ( ns16550->base + address );
}
/* Fixed ISA serial port base addresses */
#define COM1_BASE 0x3f8
#define COM2_BASE 0x2f8
#define COM3_BASE 0x3e8
#define COM4_BASE 0x2e8
/* Fixed ISA serial ports */
extern struct ns16550_uart com1;
extern struct ns16550_uart com2;
extern struct ns16550_uart com3;
extern struct ns16550_uart com4;
/* Fixed ISA serial port names */
#define COM1 &com1.uart
#define COM2 &com2.uart
#define COM3 &com3.uart
#define COM4 &com4.uart
#endif /* _BITS_NS16550_H */

41
src/arch/x86/include/bits/uart.h
View File

@@ -1,41 +0,0 @@
#ifndef _BITS_UART_H
#define _BITS_UART_H
/** @file
*
* 16550-compatible UART
*
*/
FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
#include <stdint.h>
#include <ipxe/io.h>
/**
* Write to UART register
*
* @v uart UART
* @v addr Register address
* @v data Data
*/
static inline __attribute__ (( always_inline )) void
uart_write ( struct uart *uart, unsigned int addr, uint8_t data ) {
outb ( data, ( uart->base + addr ) );
}
/**
* Read from UART register
*
* @v uart UART
* @v addr Register address
* @ret data Data
*/
static inline __attribute__ (( always_inline )) uint8_t
uart_read ( struct uart *uart, unsigned int addr ) {
return inb ( uart->base + addr );
}
extern int uart_select ( struct uart *uart, unsigned int port );
#endif /* _BITS_UART_H */

17
src/arch/x86/interface/syslinux/comboot_call.c
View File

@@ -37,6 +37,7 @@ FILE_LICENCE ( GPL2_OR_LATER );
#include <ipxe/posix_io.h>
#include <ipxe/process.h>
#include <ipxe/serial.h>
#include <ipxe/ns16550.h>
#include <ipxe/init.h>
#include <ipxe/image.h>
#include <ipxe/version.h>
@@ -253,8 +254,8 @@ static __asmcall __used void int21 ( struct i386_all_regs *ix86 ) {
break;
case 0x04: /* Write Character to Serial Port */
if ( serial_console.base ) {
uart_transmit ( &serial_console, ix86->regs.dl );
if ( serial_console ) {
uart_transmit ( serial_console, ix86->regs.dl );
ix86->flags &= ~CF;
}
break;
@@ -445,9 +446,13 @@ static __asmcall __used void int22 ( struct i386_all_regs *ix86 ) {
break;
case 0x000B: /* Get Serial Console Configuration */
if ( serial_console.base ) {
ix86->regs.dx = ( ( intptr_t ) serial_console.base );
ix86->regs.cx = serial_console.divisor;
if ( serial_console ) {
struct ns16550_uart *comport =
container_of ( serial_console,
struct ns16550_uart, uart );
ix86->regs.dx = ( ( intptr_t ) comport->base );
ix86->regs.cx = comport->divisor;
ix86->regs.bx = 0;
ix86->flags &= ~CF;
}
@@ -685,4 +690,4 @@ void unhook_comboot_interrupts ( ) {
}
/* Avoid dragging in serial console support unconditionally */
struct uart serial_console __attribute__ (( weak ));
struct uart *serial_console __attribute__ (( weak ));

42
src/core/gdbserial.c
View File

@@ -25,20 +25,12 @@ FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
#include <stddef.h>
#include <stdio.h>
#include <stdlib.h>
#include <assert.h>
#include <ipxe/uart.h>
#include <ipxe/gdbstub.h>
#include <ipxe/gdbserial.h>
#include <config/serial.h>
/* UART port number */
#ifdef COMCONSOLE
#define GDBSERIAL_PORT COMCONSOLE
#else
#define GDBSERIAL_PORT 0
#endif
/* UART baud rate */
#ifdef COMPRESERVE
#define GDBSERIAL_BAUD 0
@@ -47,37 +39,30 @@ FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
#endif
/** GDB serial UART */
static struct uart gdbserial_uart;
static struct uart *gdbserial_uart;
struct gdb_transport serial_gdb_transport __gdb_transport;
static size_t gdbserial_recv ( char *buf, size_t len ) {
assert ( len > 0 );
while ( ! uart_data_ready ( &gdbserial_uart ) ) {}
buf[0] = uart_receive ( &gdbserial_uart );
while ( ! uart_data_ready ( gdbserial_uart ) ) {}
buf[0] = uart_receive ( gdbserial_uart );
return 1;
}
static void gdbserial_send ( const char *buf, size_t len ) {
while ( len-- > 0 ) {
uart_transmit ( &gdbserial_uart, *buf++ );
uart_transmit ( gdbserial_uart, *buf++ );
}
}
static int gdbserial_init ( int argc, char **argv ) {
unsigned int port;
char *endp;
const char *port;
if ( argc == 0 ) {
port = GDBSERIAL_PORT;
} else if ( argc == 1 ) {
port = strtoul ( argv[0], &endp, 10 );
if ( *endp ) {
printf ( "serial: invalid port\n" );
return 1;
}
if ( argc == 1 ) {
port = argv[0];
} else {
printf ( "serial: syntax <port>\n" );
return 1;
@@ -98,14 +83,19 @@ struct gdb_transport serial_gdb_transport __gdb_transport = {
.send = gdbserial_send,
};
struct gdb_transport * gdbserial_configure ( unsigned int port,
struct gdb_transport * gdbserial_configure ( const char *name,
unsigned int baud ) {
int rc;
if ( ( rc = uart_select ( &gdbserial_uart, port ) ) != 0 )
return NULL;
uart_put ( gdbserial_uart );
gdbserial_uart = NULL;
if ( ( rc = uart_init ( &gdbserial_uart, baud ) ) != 0 )
gdbserial_uart = uart_find ( name );
if ( ! gdbserial_uart )
return NULL;
uart_get ( gdbserial_uart );
if ( ( rc = uart_init ( gdbserial_uart, baud ) ) != 0 )
return NULL;
return &serial_gdb_transport;

62
src/core/serial.c
View File

@@ -35,6 +35,7 @@ FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
#include <ipxe/uart.h>
#include <ipxe/console.h>
#include <ipxe/serial.h>
#include <ipxe/ns16550.h>
#include <config/console.h>
#include <config/serial.h>
@@ -44,22 +45,21 @@ FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
#define CONSOLE_SERIAL ( CONSOLE_USAGE_ALL & ~CONSOLE_USAGE_LOG )
#endif
/* UART port number */
#ifdef COMCONSOLE
#define CONSOLE_PORT COMCONSOLE
#else
#define CONSOLE_PORT 0
/* Serial console UART */
#ifndef COMCONSOLE
#define COMCONSOLE NULL
#endif
/* UART baud rate */
#ifdef COMPRESERVE
#define CONSOLE_BAUD 0
#else
#define CONSOLE_BAUD COMSPEED
/* Serial console baud rate */
#ifndef COMSPEED
#define COMSPEED 0
#endif
/** Serial console UART */
struct uart serial_console;
/** Default serial console UART */
static struct uart * const default_serial_console = COMCONSOLE;
/** Active serial console UART */
struct uart *serial_console;
/**
* Print a character to serial console
@@ -69,11 +69,11 @@ struct uart serial_console;
static void serial_putchar ( int character ) {
/* Do nothing if we have no UART */
if ( ! serial_console.base )
if ( ! serial_console )
return;
/* Transmit character */
uart_transmit ( &serial_console, character );
uart_transmit ( serial_console, character );
}
/**
@@ -85,14 +85,14 @@ static int serial_getchar ( void ) {
uint8_t data;
/* Do nothing if we have no UART */
if ( ! serial_console.base )
if ( ! serial_console )
return 0;
/* Wait for data to be ready */
while ( ! uart_data_ready ( &serial_console ) ) {}
while ( ! uart_data_ready ( serial_console ) ) {}
/* Receive data */
data = uart_receive ( &serial_console );
data = uart_receive ( serial_console );
/* Strip any high bit and convert DEL to backspace */
data &= 0x7f;
@@ -111,11 +111,11 @@ static int serial_getchar ( void ) {
static int serial_iskey ( void ) {
/* Do nothing if we have no UART */
if ( ! serial_console.base )
if ( ! serial_console )
return 0;
/* Check UART */
return uart_data_ready ( &serial_console );
return uart_data_ready ( serial_console );
}
/** Serial console */
@@ -128,25 +128,23 @@ struct console_driver serial_console_driver __console_driver = {
/** Initialise serial console */
static void serial_init ( void ) {
struct uart *uart = default_serial_console;
int rc;
/* Do nothing if we have no default port */
if ( ! CONSOLE_PORT )
if ( ! uart )
return;
/* Select UART */
if ( ( rc = uart_select ( &serial_console, CONSOLE_PORT ) ) != 0 ) {
DBG ( "Could not select UART %d: %s\n",
CONSOLE_PORT, strerror ( rc ) );
return;
}
/* Initialise UART */
if ( ( rc = uart_init ( &serial_console, CONSOLE_BAUD ) ) != 0 ) {
DBG ( "Could not initialise UART %d baud %d: %s\n",
CONSOLE_PORT, CONSOLE_BAUD, strerror ( rc ) );
if ( ( rc = uart_init ( uart, COMSPEED ) ) != 0 ) {
DBGC ( uart, "SERIAL could not initialise %s baud %d: %s\n",
uart->name, COMSPEED, strerror ( rc ) );
return;
}
/* Record UART as serial console */
serial_console = uart;
DBGC ( uart, "SERIAL using %s\n", uart->name );
}
/**
@@ -157,11 +155,11 @@ static void serial_init ( void ) {
static void serial_shutdown ( int flags __unused ) {
/* Do nothing if we have no UART */
if ( ! serial_console.base )
if ( ! serial_console )
return;
/* Flush any pending output */
uart_flush ( &serial_console );
uart_flush ( serial_console );
/* Leave console enabled; it's still usable */
}

186
src/core/uart.c
View File

@@ -1,5 +1,5 @@
/*
* Copyright (C) 2014 Michael Brown <mbrown@fensystems.co.uk>.
* Copyright (C) 2025 Michael Brown <mbrown@fensystems.co.uk>.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License as
@@ -25,125 +25,139 @@ FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
/** @file
*
* 16550-compatible UART
* Generic UARTs
*
*/
#include <unistd.h>
#include <stdlib.h>
#include <strings.h>
#include <errno.h>
#include <ipxe/uart.h>
/** Timeout for transmit holding register to become empty */
#define UART_THRE_TIMEOUT_MS 100
/** List of registered UARTs */
LIST_HEAD ( uarts );
/** Timeout for transmitter to become empty */
#define UART_TEMT_TIMEOUT_MS 1000
static void null_uart_transmit ( struct uart *uart __unused,
uint8_t byte __unused ) {
}
static int null_uart_data_ready ( struct uart *uart __unused ) {
return 0;
}
static uint8_t null_uart_receive ( struct uart *uart __unused ) {
return 0;
}
static int null_uart_init ( struct uart *uart __unused,
unsigned int baud __unused ) {
return 0;
}
static void null_uart_flush ( struct uart *uart __unused ) {
}
/** Null UART operations */
struct uart_operations null_uart_operations = {
.transmit = null_uart_transmit,
.data_ready = null_uart_data_ready,
.receive = null_uart_receive,
.init = null_uart_init,
.flush = null_uart_flush,
};
/**
* Transmit data
* Allocate UART
*
* @v uart UART
* @v data Data
* @v priv_len Length of private data
* @ret uart UART, or NULL on error
*/
void uart_transmit ( struct uart *uart, uint8_t data ) {
unsigned int i;
uint8_t lsr;
struct uart * alloc_uart ( size_t priv_len ) {
struct uart *uart;
/* Wait for transmitter holding register to become empty */
for ( i = 0 ; i < UART_THRE_TIMEOUT_MS ; i++ ) {
lsr = uart_read ( uart, UART_LSR );
if ( lsr & UART_LSR_THRE )
break;
mdelay ( 1 );
}
/* Allocate and initialise UART */
uart = zalloc ( sizeof ( *uart ) + priv_len );
if ( ! uart )
return NULL;
uart->priv = ( ( ( void * ) uart ) + sizeof ( *uart ) );
/* Transmit data (even if we timed out) */
uart_write ( uart, UART_THR, data );
return uart;
}
/**
* Flush data
* Register fixed UARTs (when not provided by platform)
*
* @v uart UART
*/
void uart_flush ( struct uart *uart ) {
unsigned int i;
uint8_t lsr;
/* Wait for transmitter and receiver to become empty */
for ( i = 0 ; i < UART_TEMT_TIMEOUT_MS ; i++ ) {
uart_read ( uart, UART_RBR );
lsr = uart_read ( uart, UART_LSR );
if ( ( lsr & UART_LSR_TEMT ) && ! ( lsr & UART_LSR_DR ) )
break;
}
}
/**
* Check for existence of UART
*
* @v uart UART
* @ret rc Return status code
*/
int uart_exists ( struct uart *uart ) {
/* Fail if no UART port is defined */
if ( ! uart->base )
return -ENODEV;
/* Fail if UART scratch register seems not to be present */
uart_write ( uart, UART_SCR, 0x18 );
if ( uart_read ( uart, UART_SCR ) != 0x18 )
return -ENODEV;
uart_write ( uart, UART_SCR, 0xae );
if ( uart_read ( uart, UART_SCR ) != 0xae )
return -ENODEV;
__weak int uart_register_fixed ( void ) {
return 0;
}
/**
* Initialise UART
* Register UART
*
* @v uart UART
* @v baud Baud rate, or zero to leave unchanged
* @ret rc Return status code
*/
int uart_init ( struct uart *uart, unsigned int baud ) {
uint8_t dlm;
uint8_t dll;
int uart_register ( struct uart *uart ) {
/* Add to list of registered UARTs */
uart_get ( uart );
list_add_tail ( &uart->list, &uarts );
DBGC ( uart, "UART %s registered\n", uart->name );
return 0;
}
/**
* Unregister UART
*
* @v uart UART
*/
void uart_unregister ( struct uart *uart ) {
/* Remove from list of registered UARTs */
list_del ( &uart->list );
uart_put ( uart );
}
/**
* Find named UART
*
* @v name UART name
* @ret uart UART, or NULL if not found
*/
struct uart * uart_find ( const char *name ) {
struct uart *uart;
unsigned int index;
char *endp;
int rc;
/* Check for existence of UART */
if ( ( rc = uart_exists ( uart ) ) != 0 )
return rc;
/* Configure divisor and line control register, if applicable */
uart_write ( uart, UART_LCR, ( UART_LCR_8N1 | UART_LCR_DLAB ) );
if ( baud ) {
uart->divisor = ( UART_MAX_BAUD / baud );
dlm = ( ( uart->divisor >> 8 ) & 0xff );
dll = ( ( uart->divisor >> 0 ) & 0xff );
uart_write ( uart, UART_DLM, dlm );
uart_write ( uart, UART_DLL, dll );
} else {
dlm = uart_read ( uart, UART_DLM );
dll = uart_read ( uart, UART_DLL );
uart->divisor = ( ( dlm << 8 ) | dll );
/* Register fixed platform UARTs if not already registered */
if ( list_empty ( &uarts ) ) {
if ( ( rc = uart_register_fixed() ) != 0 ) {
DBGC ( &uarts, "UART could not register fixed UARTs: "
"%s\n", strerror ( rc ) );
/* Continue anyway */
}
}
uart_write ( uart, UART_LCR, UART_LCR_8N1 );
/* Disable interrupts */
uart_write ( uart, UART_IER, 0 );
/* Try parsing name as a numeric index */
index = strtoul ( name, &endp, 10 );
/* Enable FIFOs */
uart_write ( uart, UART_FCR, UART_FCR_FE );
/* Find matching UART, if any */
list_for_each_entry ( uart, &uarts, list ) {
/* Assert DTR and RTS */
uart_write ( uart, UART_MCR, ( UART_MCR_DTR | UART_MCR_RTS ) );
/* Check for a matching name */
if ( strcasecmp ( name, uart->name ) == 0 )
return uart;
/* Flush any stale data */
uart_flush ( uart );
/* Check for a matching numeric index */
if ( ( *endp == '\0' ) && ( index-- == 0 ) )
return uart;
}
return 0;
DBGC ( &uarts, "UART %s not found\n", name );
return NULL;
}

179
src/drivers/uart/ns16550.c Normal file
View File

@@ -0,0 +1,179 @@
/*
* Copyright (C) 2025 Michael Brown <mbrown@fensystems.co.uk>.
*
* 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 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., 51 Franklin Street, Fifth Floor, Boston, MA
* 02110-1301, USA.
*
* You can also choose to distribute this program under the terms of
* the Unmodified Binary Distribution Licence (as given in the file
* COPYING.UBDL), provided that you have satisfied its requirements.
*/
FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
/** @file
*
* 16550-compatible UART
*
*/
#include <unistd.h>
#include <errno.h>
#include <ipxe/uart.h>
#include <ipxe/ns16550.h>
/** Timeout for transmit holding register to become empty */
#define NS16550_THRE_TIMEOUT_MS 100
/** Timeout for transmitter to become empty */
#define NS16550_TEMT_TIMEOUT_MS 1000
/**
* Transmit data
*
* @v uart UART
* @v data Data
*/
static void ns16550_transmit ( struct uart *uart, uint8_t data ) {
struct ns16550_uart *ns16550 =
container_of ( uart, struct ns16550_uart, uart );
unsigned int i;
uint8_t lsr;
/* Wait for transmitter holding register to become empty */
for ( i = 0 ; i < NS16550_THRE_TIMEOUT_MS ; i++ ) {
lsr = ns16550_read ( ns16550, NS16550_LSR );
if ( lsr & NS16550_LSR_THRE )
break;
mdelay ( 1 );
}
/* Transmit data (even if we timed out) */
ns16550_write ( ns16550, NS16550_THR, data );
}
/**
* Check if data is ready
*
* @v uart UART
* @ret ready Data is ready
*/
static int ns16550_data_ready ( struct uart *uart ) {
struct ns16550_uart *ns16550 =
container_of ( uart, struct ns16550_uart, uart );
uint8_t lsr;
/* Check for receive data ready */
lsr = ns16550_read ( ns16550, NS16550_LSR );
return ( lsr & NS16550_LSR_DR );
}
/**
* Receive data
*
* @v uart UART
* @ret data Data
*/
static uint8_t ns16550_receive ( struct uart *uart ) {
struct ns16550_uart *ns16550 =
container_of ( uart, struct ns16550_uart, uart );
uint8_t rbr;
/* Receive byte */
rbr = ns16550_read ( ns16550, NS16550_RBR );
return rbr;
}
/**
* Flush transmitted data
*
* @v uart UART
*/
static void ns16550_flush ( struct uart *uart ) {
struct ns16550_uart *ns16550 =
container_of ( uart, struct ns16550_uart, uart );
unsigned int i;
uint8_t lsr;
/* Wait for transmitter to become empty */
for ( i = 0 ; i < NS16550_TEMT_TIMEOUT_MS ; i++ ) {
lsr = ns16550_read ( ns16550, NS16550_LSR );
if ( lsr & NS16550_LSR_TEMT )
break;
}
}
/**
* Initialise UART
*
* @v uart UART
* @v baud Baud rate, or zero to leave unchanged
* @ret rc Return status code
*/
static int ns16550_init ( struct uart *uart, unsigned int baud ) {
struct ns16550_uart *ns16550 =
container_of ( uart, struct ns16550_uart, uart );
uint8_t dlm;
uint8_t dll;
/* Fail if UART scratch register seems not to be present */
ns16550_write ( ns16550, NS16550_SCR, 0x18 );
if ( ns16550_read ( ns16550, NS16550_SCR ) != 0x18 )
return -ENODEV;
ns16550_write ( ns16550, NS16550_SCR, 0xae );
if ( ns16550_read ( ns16550, NS16550_SCR ) != 0xae )
return -ENODEV;
/* Configure divisor and line control register, if applicable */
ns16550_write ( ns16550, NS16550_LCR,
( NS16550_LCR_8N1 | NS16550_LCR_DLAB ) );
if ( baud ) {
ns16550->divisor = ( NS16550_MAX_BAUD / baud );
dlm = ( ( ns16550->divisor >> 8 ) & 0xff );
dll = ( ( ns16550->divisor >> 0 ) & 0xff );
ns16550_write ( ns16550, NS16550_DLM, dlm );
ns16550_write ( ns16550, NS16550_DLL, dll );
} else {
dlm = ns16550_read ( ns16550, NS16550_DLM );
dll = ns16550_read ( ns16550, NS16550_DLL );
ns16550->divisor = ( ( dlm << 8 ) | dll );
}
ns16550_write ( ns16550, NS16550_LCR, NS16550_LCR_8N1 );
/* Disable interrupts */
ns16550_write ( ns16550, NS16550_IER, 0 );
/* Enable FIFOs */
ns16550_write ( ns16550, NS16550_FCR, NS16550_FCR_FE );
/* Assert DTR and RTS */
ns16550_write ( ns16550, NS16550_MCR,
( NS16550_MCR_DTR | NS16550_MCR_RTS ) );
/* Flush any stale received data */
while ( ns16550_data_ready ( uart ) )
ns16550_receive ( uart );
return 0;
}
/** 16550 UART operations */
struct uart_operations ns16550_operations = {
.transmit = ns16550_transmit,
.data_ready = ns16550_data_ready,
.receive = ns16550_receive,
.init = ns16550_init,
.flush = ns16550_flush,
};

8
src/include/bits/uart.h → src/include/bits/ns16550.h
View File

@@ -1,9 +1,9 @@
#ifndef _BITS_UART_H
#define _BITS_UART_H
#ifndef _BITS_NS16550_H
#define _BITS_NS16550_H
/** @file
*
* Dummy architecture-specific UART
* Dummy architecture-specific 16550-compatible UART
*
* This file is included only if the architecture does not provide its
* own version of this file.
@@ -12,4 +12,4 @@
FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
#endif /* _BITS_UART_H */
#endif /* _BITS_NS16550_H */

1
src/include/ipxe/errfile.h
View File

@@ -109,6 +109,7 @@ FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
#define ERRFILE_spi_bit ( ERRFILE_DRIVER | 0x00130000 )
#define ERRFILE_nvsvpd ( ERRFILE_DRIVER | 0x00140000 )
#define ERRFILE_uart ( ERRFILE_DRIVER | 0x00150000 )
#define ERRFILE_ns16550 ( ERRFILE_DRIVER | 0x00160000 )
#define ERRFILE_3c509 ( ERRFILE_DRIVER | 0x00200000 )
#define ERRFILE_bnx2 ( ERRFILE_DRIVER | 0x00210000 )

2
src/include/ipxe/gdbserial.h
View File

@@ -11,7 +11,7 @@ FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
struct gdb_transport;
extern struct gdb_transport * gdbserial_configure ( unsigned int port,
extern struct gdb_transport * gdbserial_configure ( const char *port,
unsigned int baud );
#endif /* _IPXE_GDBSERIAL_H */

112
src/include/ipxe/ns16550.h Normal file
View File

@@ -0,0 +1,112 @@
#ifndef _IPXE_NS16550_H
#define _IPXE_NS16550_H
/** @file
*
* 16550-compatible UART
*
*/
FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
#include <ipxe/uart.h>
/** Transmitter holding register */
#define NS16550_THR 0x00
/** Receiver buffer register */
#define NS16550_RBR 0x00
/** Interrupt enable register */
#define NS16550_IER 0x01
/** FIFO control register */
#define NS16550_FCR 0x02
#define NS16550_FCR_FE 0x01 /**< FIFO enable */
/** Line control register */
#define NS16550_LCR 0x03
#define NS16550_LCR_WLS0 0x01 /**< Word length select bit 0 */
#define NS16550_LCR_WLS1 0x02 /**< Word length select bit 1 */
#define NS16550_LCR_STB 0x04 /**< Number of stop bits */
#define NS16550_LCR_PEN 0x08 /**< Parity enable */
#define NS16550_LCR_EPS 0x10 /**< Even parity select */
#define NS16550_LCR_DLAB 0x80 /**< Divisor latch access bit */
#define NS16550_LCR_WORD_LEN(x) ( ( (x) - 5 ) << 0 ) /**< Word length */
#define NS16550_LCR_STOP_BITS(x) ( ( (x) - 1 ) << 2 ) /**< Stop bits */
#define NS16550_LCR_PARITY(x) ( ( (x) - 0 ) << 3 ) /**< Parity */
/**
* Calculate line control register value
*
* @v word_len Word length (5-8)
* @v parity Parity (0=none, 1=odd, 3=even)
* @v stop_bits Stop bits (1-2)
* @ret lcr Line control register value
*/
#define NS16550_LCR_WPS( word_len, parity, stop_bits ) \
( NS16550_LCR_WORD_LEN ( (word_len) ) | \
NS16550_LCR_PARITY ( (parity) ) | \
NS16550_LCR_STOP_BITS ( (stop_bits) ) )
/** Default LCR value: 8 data bits, no parity, one stop bit */
#define NS16550_LCR_8N1 NS16550_LCR_WPS ( 8, 0, 1 )
/** Modem control register */
#define NS16550_MCR 0x04
#define NS16550_MCR_DTR 0x01 /**< Data terminal ready */
#define NS16550_MCR_RTS 0x02 /**< Request to send */
/** Line status register */
#define NS16550_LSR 0x05
#define NS16550_LSR_DR 0x01 /**< Data ready */
#define NS16550_LSR_THRE 0x20 /**< Transmitter holding reg. empty */
#define NS16550_LSR_TEMT 0x40 /**< Transmitter empty */
/** Scratch register */
#define NS16550_SCR 0x07
/** Divisor latch (least significant byte) */
#define NS16550_DLL 0x00
/** Divisor latch (most significant byte) */
#define NS16550_DLM 0x01
/** Maximum baud rate */
#define NS16550_MAX_BAUD 115200
/** A 16550-compatible UART */
struct ns16550_uart {
/** Generic UART */
struct uart uart;
/** Register base address */
void *base;
/** Baud rate divisor */
uint16_t divisor;
};
#include <bits/ns16550.h>
/** Dummy COM1 UART for non-x86 platforms
*
* The architecture-independent config/serial.h header has long
* included the line
*
* #define COMCONSOLE COM1
*
* which is meaningless on non-x86 platforms where there is no COM1
* port. Allow COM1 to be treated as equivalent to "no UART" on
* non-x86 platforms, to avoid breaking existing build configurations.
*/
#ifndef COM1
#define COM1 NULL
#endif
void ns16550_write ( struct ns16550_uart *ns16550, unsigned int address,
uint8_t data );
uint8_t ns16550_read ( struct ns16550_uart *ns16550, unsigned int address );
extern struct uart_operations ns16550_operations;
#endif /* _IPXE_NS16550_H */

2
src/include/ipxe/serial.h
View File

@@ -11,6 +11,6 @@ FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
#include <ipxe/uart.h>
extern struct uart serial_console;
extern struct uart *serial_console;
#endif /* _IPXE_SERIAL_H */

238
src/include/ipxe/uart.h
View File

@@ -3,128 +3,174 @@
/** @file
*
* 16550-compatible UART
* Generic UART
*
*/
FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
#include <stdint.h>
#include <ipxe/refcnt.h>
#include <ipxe/list.h>
/** Transmitter holding register */
#define UART_THR 0x00
/** Receiver buffer register */
#define UART_RBR 0x00
/** Interrupt enable register */
#define UART_IER 0x01
/** FIFO control register */
#define UART_FCR 0x02
#define UART_FCR_FE 0x01 /**< FIFO enable */
/** Line control register */
#define UART_LCR 0x03
#define UART_LCR_WLS0 0x01 /**< Word length select bit 0 */
#define UART_LCR_WLS1 0x02 /**< Word length select bit 1 */
#define UART_LCR_STB 0x04 /**< Number of stop bits */
#define UART_LCR_PEN 0x08 /**< Parity enable */
#define UART_LCR_EPS 0x10 /**< Even parity select */
#define UART_LCR_DLAB 0x80 /**< Divisor latch access bit */
#define UART_LCR_WORD_LEN(x) ( ( (x) - 5 ) << 0 ) /**< Word length */
#define UART_LCR_STOP_BITS(x) ( ( (x) - 1 ) << 2 ) /**< Stop bits */
#define UART_LCR_PARITY(x) ( ( (x) - 0 ) << 3 ) /**< Parity */
/**
* Calculate line control register value
*
* @v word_len Word length (5-8)
* @v parity Parity (0=none, 1=odd, 3=even)
* @v stop_bits Stop bits (1-2)
* @ret lcr Line control register value
*/
#define UART_LCR_WPS( word_len, parity, stop_bits ) \
( UART_LCR_WORD_LEN ( (word_len) ) | \
UART_LCR_PARITY ( (parity) ) | \
UART_LCR_STOP_BITS ( (stop_bits) ) )
/** Default LCR value: 8 data bits, no parity, one stop bit */
#define UART_LCR_8N1 UART_LCR_WPS ( 8, 0, 1 )
/** Modem control register */
#define UART_MCR 0x04
#define UART_MCR_DTR 0x01 /**< Data terminal ready */
#define UART_MCR_RTS 0x02 /**< Request to send */
/** Line status register */
#define UART_LSR 0x05
#define UART_LSR_DR 0x01 /**< Data ready */
#define UART_LSR_THRE 0x20 /**< Transmitter holding register empty */
#define UART_LSR_TEMT 0x40 /**< Transmitter empty */
/** Scratch register */
#define UART_SCR 0x07
/** Divisor latch (least significant byte) */
#define UART_DLL 0x00
/** Divisor latch (most significant byte) */
#define UART_DLM 0x01
/** Maximum baud rate */
#define UART_MAX_BAUD 115200
/** A 16550-compatible UART */
/** A generic UART */
struct uart {
/** I/O port base address */
void *base;
/** Baud rate divisor */
uint16_t divisor;
/** Reference count */
struct refcnt refcnt;
/** Name */
const char *name;
/** List of registered UARTs */
struct list_head list;
/** UART operations */
struct uart_operations *op;
/** Driver-private data */
void *priv;
};
/** Symbolic names for port indexes */
enum uart_port {
COM1 = 1,
COM2 = 2,
COM3 = 3,
COM4 = 4,
/** UART operations */
struct uart_operations {
/**
* Transmit byte
*
* @v uart UART
* @v byte Byte to transmit
* @ret rc Return status code
*/
void ( * transmit ) ( struct uart *uart, uint8_t byte );
/**
* Check if data is ready
*
* @v uart UART
* @ret ready Data is ready
*/
int ( * data_ready ) ( struct uart *uart );
/**
* Receive byte
*
* @v uart UART
* @ret byte Received byte
*/
uint8_t ( * receive ) ( struct uart *uart );
/**
* Initialise UART
*
* @v uart UART
* @v baud Baud rate, or zero to leave unchanged
* @ret rc Return status code
*/
int ( * init ) ( struct uart *uart, unsigned int baud );
/**
* Flush transmitted data
*
* @v uart UART
*/
void ( * flush ) ( struct uart *uart );
};
#include <bits/uart.h>
void uart_write ( struct uart *uart, unsigned int addr, uint8_t data );
uint8_t uart_read ( struct uart *uart, unsigned int addr );
int uart_select ( struct uart *uart, unsigned int port );
/**
* Check if received data is ready
* Transmit byte
*
* @v uart UART
* @v byte Byte to transmit
* @ret rc Return status code
*/
static inline __attribute__ (( always_inline )) void
uart_transmit ( struct uart *uart, uint8_t byte ) {
uart->op->transmit ( uart, byte );
}
/**
* Check if data is ready
*
* @v uart UART
* @ret ready Data is ready
*/
static inline int uart_data_ready ( struct uart *uart ) {
uint8_t lsr;
static inline __attribute__ (( always_inline )) int
uart_data_ready ( struct uart *uart ) {
lsr = uart_read ( uart, UART_LSR );
return ( lsr & UART_LSR_DR );
return uart->op->data_ready ( uart );
}
/**
* Receive data
* Receive byte
*
* @v uart UART
* @ret data Data
* @ret byte Received byte
*/
static inline uint8_t uart_receive ( struct uart *uart ) {
static inline __attribute__ (( always_inline )) uint8_t
uart_receive ( struct uart *uart ) {
return uart_read ( uart, UART_RBR );
return uart->op->receive ( uart );
}
extern void uart_transmit ( struct uart *uart, uint8_t data );
extern void uart_flush ( struct uart *uart );
extern int uart_exists ( struct uart *uart );
extern int uart_init ( struct uart *uart, unsigned int baud );
/**
* Initialise UART
*
* @v uart UART
* @v baud Baud rate, or zero to leave unchanged
* @ret rc Return status code
*/
static inline __attribute__ (( always_inline )) int
uart_init ( struct uart *uart, unsigned int baud ) {
return uart->op->init ( uart, baud );
}
/**
* Flush transmitted data
*
* @v uart UART
*/
static inline __attribute__ (( always_inline )) void
uart_flush ( struct uart *uart ) {
uart->op->flush ( uart );
}
extern struct list_head uarts;
extern struct uart_operations null_uart_operations;
/**
* Get reference to UART
*
* @v uart UART
* @ret uart UART
*/
static inline __attribute__ (( always_inline )) struct uart *
uart_get ( struct uart *uart ) {
ref_get ( &uart->refcnt );
return uart;
}
/**
* Drop reference to UART
*
* @v uart UART
*/
static inline __attribute__ (( always_inline )) void
uart_put ( struct uart *uart ) {
ref_put ( &uart->refcnt );
}
/**
* Nullify UART
*
* @v uart UART
*/
static inline __attribute__ (( always_inline )) void
uart_nullify ( struct uart *uart ) {
uart->op = &null_uart_operations;
}
extern struct uart * alloc_uart ( size_t priv_len );
extern int uart_register ( struct uart *uart );
extern int uart_register_fixed ( void );
extern void uart_unregister ( struct uart *uart );
extern struct uart * uart_find ( const char *name );
#endif /* _IPXE_UART_H */