[ipxe-devel] [PATCH] [serial] Allow serial port configuration at runtime
Faidon Liambotis
paravoid at debian.org
Sat Jun 15 15:10:27 UTC 2019
Add configuration variables for the serial port and its options,
allowing the configuration of a serial port at runtime via either "set",
or DHCP options.
The new "serial-port" option accepts values of "1" through "4" for COM1
to COM4 respectively. For the serial options, rather than adding a
configuration variable for each of them (baud, parity etc.) and
complicate both the code and the configuration unncessarily, add a
single, generic "serial-options" setting that accepts string values such
as "115200" or "38400n81". It also accepts the special value "preserve"
to preserve the previous configuration of the serial port.
Note that this commit does _not_ enable CONSOLE_SERIAL by default,
although that could potentially follow in a subsequent commit, given
this would be now a no-op unless a port is explicitly configured.
Signed-off-by: Faidon Liambotis <paravoid at debian.org>
---
src/config/serial.h | 26 ++---
src/core/serial.c | 214 +++++++++++++++++++++++++++++--------
src/include/ipxe/dhcp.h | 4 +
src/include/ipxe/errfile.h | 1 +
4 files changed, 186 insertions(+), 59 deletions(-)
diff --git a/src/config/serial.h b/src/config/serial.h
index 27040dc5..057d9180 100644
--- a/src/config/serial.h
+++ b/src/config/serial.h
@@ -5,27 +5,21 @@
*
* Serial port configuration
*
- * These options affect the operation of the serial console. They
- * take effect only if the serial console is included using the
- * CONSOLE_SERIAL option.
+ * These options affect the operation of the serial console. They take effect
+ * only if the serial console is included using the CONSOLE_SERIAL option.
+ * These settings only the default settings, and can all be set (or overriden)
+ * at runtime.
*
*/
FILE_LICENCE ( GPL2_OR_LATER );
-#define COMCONSOLE COM1 /* I/O port address */
-
-/* Keep settings from a previous user of the serial port (e.g. lilo or
- * LinuxBIOS), ignoring COMSPEED, COMDATA, COMPARITY and COMSTOP.
- */
-#undef COMPRESERVE
-
-#ifndef COMPRESERVE
-#define COMSPEED 115200 /* Baud rate */
-#define COMDATA 8 /* Data bits */
-#define COMPARITY 0 /* Parity: 0=None, 1=Odd, 2=Even */
-#define COMSTOP 1 /* Stop bits */
-#endif
+//#define COMCONSOLE COM1 /* I/O port address */
+#define COMPRESERVE 0 /* Preserve settings by another bootloader */
+#define COMSPEED 115200 /* Baud rate */
+#define COMDATA 8 /* Data bits */
+#define COMPARITY 0 /* Parity: 0=None, 1=Odd, 2=Even */
+#define COMSTOP 1 /* Stop bits */
#include <config/named.h>
#include NAMED_CONFIG(serial.h)
diff --git a/src/core/serial.c b/src/core/serial.c
index bef9ccba..7d33b9fc 100644
--- a/src/core/serial.c
+++ b/src/core/serial.c
@@ -30,8 +30,12 @@ FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
*/
#include <stddef.h>
+#include <stdlib.h>
#include <string.h>
+#include <errno.h>
#include <ipxe/init.h>
+#include <ipxe/dhcp.h>
+#include <ipxe/settings.h>
#include <ipxe/uart.h>
#include <ipxe/console.h>
#include <ipxe/serial.h>
@@ -51,20 +55,6 @@ FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
#define CONSOLE_PORT 0
#endif
-/* UART baud rate */
-#ifdef COMPRESERVE
-#define CONSOLE_BAUD 0
-#else
-#define CONSOLE_BAUD COMSPEED
-#endif
-
-/* UART line control register value */
-#ifdef COMPRESERVE
-#define CONSOLE_LCR 0
-#else
-#define CONSOLE_LCR UART_LCR_WPS ( COMDATA, COMPARITY, COMSTOP )
-#endif
-
/** Serial console UART */
struct uart serial_console;
@@ -133,30 +123,6 @@ struct console_driver serial_console_driver __console_driver = {
.usage = CONSOLE_SERIAL,
};
-/** Initialise serial console */
-static void serial_init ( void ) {
- int rc;
-
- /* Do nothing if we have no default port */
- if ( ! CONSOLE_PORT )
- 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,
- CONSOLE_LCR ) ) != 0 ) {
- DBG ( "Could not initialise UART %d baud %d LCR %#02x: %s\n",
- CONSOLE_PORT, CONSOLE_BAUD, CONSOLE_LCR, strerror ( rc ));
- return;
- }
-}
-
/**
* Shut down serial console
*
@@ -174,13 +140,175 @@ static void serial_shutdown ( int flags __unused ) {
/* Leave console enabled; it's still usable */
}
-/** Serial console initialisation function */
-struct init_fn serial_console_init_fn __init_fn ( INIT_CONSOLE ) = {
- .initialise = serial_init,
-};
-
/** Serial console startup function */
struct startup_fn serial_startup_fn __startup_fn ( STARTUP_EARLY ) = {
.name = "serial",
.shutdown = serial_shutdown,
};
+
+/** Serial console port setting */
+const struct setting serial_port_setting __setting ( SETTING_MISC, serial-port ) = {
+ .name = "serial-port",
+ .description = "Serial port",
+ .tag = DHCP_EB_SERIAL_PORT,
+ .type = &setting_type_uint8,
+};
+const struct setting serial_options_setting __setting ( SETTING_MISC, serial-options ) = {
+ .name = "serial-options",
+ .description = "Serial port options",
+ .tag = DHCP_EB_SERIAL_OPTIONS,
+ .type = &setting_type_string,
+};
+
+/**
+ * Parse a string with options in the format of BBBBPDS where:
+ * - BBBB is the baud rate
+ * - P is parity ("n" for none, "o" for odd, "e" for even)
+ * - D is data bits
+ * - S is stop bits
+ *
+ * @c rc Return status code
+ * @v baud Pointer to an integer for baud rate
+ * @v lcr Pointer to an integer for the line control register
+ */
+static int serial_parse_options ( const char *options,
+ uint32_t *baud, uint8_t *lcr ) {
+ int rc = 0;
+ char *endp;
+ uint32_t speed;
+ uint8_t data, parity, stop, preserve;
+
+ /* Initialise to default values; any of these can be overriden later */
+ speed = COMSPEED;
+ data = COMDATA;
+ parity = COMPARITY;
+ stop = COMSTOP;
+ preserve = COMPRESERVE;
+
+ if ( !options || strlen ( options ) == 0 )
+ goto out;
+
+ if ( strcmp ( options, "preserve" ) == 0 ) {
+ preserve = 1;
+ goto out;
+ }
+
+ speed = strtoul( options, &endp, 10 );
+
+ /* No baud rate found */
+ if ( endp == options ) {
+ rc = -EINVAL;
+ goto out;
+ }
+
+ /* Next character is parity */
+ if ( *endp ) {
+ switch( *endp++ ) {
+ case 'n':
+ parity = 0;
+ break;
+ case 'o':
+ parity = 1;
+ break;
+ case 'e':
+ parity = 3;
+ break;
+ default:
+ rc = -EINVAL;
+ goto out;
+ }
+ }
+
+ /* Data & stop bits follow, single numbers in ASCII */
+ if ( *endp )
+ data = *endp++ - '0';
+ if ( *endp )
+ stop = *endp++ - '0';
+
+ out:
+ if ( !preserve ) {
+ /* UART line control register */
+ *baud = speed;
+ *lcr = UART_LCR_WPS ( data, parity, stop );
+ } else {
+ /* Preserve the settings set by e.g. a previous bootloader */
+ *baud = 0;
+ *lcr = 0;
+ }
+ return rc;
+}
+
+/**
+ * Apply serial console settings
+ *
+ * @ret rc Return status code
+ */
+static int apply_serial_settings ( void ) {
+ int rc = 0;
+ char *options;
+ unsigned long port;
+ uint32_t baud;
+ uint8_t lcr;
+
+ static unsigned long old_port;
+ static uint32_t old_baud;
+ static uint8_t old_lcr;
+
+ if ( fetch_uint_setting ( NULL, &serial_port_setting, &port ) < 0 )
+ port = CONSOLE_PORT;
+
+ fetch_string_setting_copy ( NULL, &serial_options_setting, &options );
+ if ( ( rc = serial_parse_options ( options, &baud, &lcr ) ) != 0 ) {
+ goto err_parse_options;
+ }
+
+ /* Avoid reconfiguring the port if no changes are being made */
+ if ( port == old_port && baud == old_baud && lcr == old_lcr )
+ goto out_no_change;
+
+ /* Flush the old port, if configured */
+ if ( serial_console.base )
+ uart_flush ( &serial_console );
+
+ /* Disable port if we are not about to configure a new one */
+ if ( ! port ) {
+ serial_console.base = NULL;
+ goto out_no_port;
+ }
+
+ /* Select UART */
+ if ( ( rc = uart_select ( &serial_console, port ) ) != 0 ) {
+ DBG ( "Could not select UART %ld: %s\n", port, strerror ( rc ) );
+ goto err_port_select;
+ }
+
+ /* Initialise UART */
+ if ( ( rc = uart_init ( &serial_console, baud, lcr ) ) != 0 ) {
+ DBG ( "Could not initialise UART %ld baud %u LCR %#02x: %s\n",
+ port, baud, lcr, strerror ( rc ));
+ goto err_port_init;
+ }
+
+ DBG ( "Serial config using port %ld\n", port );
+
+ /* Record settings */
+ old_port = port;
+ old_baud = baud;
+ old_lcr = lcr;
+
+ /* Success */
+ rc = 0;
+
+ err_parse_options:
+ err_port_select:
+ err_port_init:
+ out_no_port:
+ out_no_change:
+ free ( options );
+ return rc;
+}
+
+/** Serial console port settings applicator */
+struct settings_applicator serial_port_applicator __settings_applicator = {
+ .apply = apply_serial_settings,
+};
diff --git a/src/include/ipxe/dhcp.h b/src/include/ipxe/dhcp.h
index b7a5f004..1b36c96c 100644
--- a/src/include/ipxe/dhcp.h
+++ b/src/include/ipxe/dhcp.h
@@ -400,6 +400,10 @@ struct dhcp_client_uuid {
/** Cross-signed certificate source */
#define DHCP_EB_CROSS_CERT DHCP_ENCAP_OPT ( DHCP_EB_ENCAP, 0x5d )
+/** Serial port configuration */
+#define DHCP_EB_SERIAL_PORT DHCP_ENCAP_OPT ( DHCP_EB_ENCAP, 0x60 )
+#define DHCP_EB_SERIAL_OPTIONS DHCP_ENCAP_OPT ( DHCP_EB_ENCAP, 0x61 )
+
/** Skip PXE DHCP protocol extensions such as ProxyDHCP
*
* If set to a non-zero value, iPXE will not wait for ProxyDHCP offers
diff --git a/src/include/ipxe/errfile.h b/src/include/ipxe/errfile.h
index 1a92b6ce..ae1258e1 100644
--- a/src/include/ipxe/errfile.h
+++ b/src/include/ipxe/errfile.h
@@ -97,6 +97,7 @@ 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_serial ( ERRFILE_DRIVER | 0x00160000 )
#define ERRFILE_3c509 ( ERRFILE_DRIVER | 0x00200000 )
#define ERRFILE_bnx2 ( ERRFILE_DRIVER | 0x00210000 )
--
2.20.1
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