[RESEND PATCH v2] netconsole: various improvements
Simon Glass
sjg at chromium.org
Wed Apr 19 03:46:29 CEST 2023
Hi Tony,
On Mon, 3 Apr 2023 at 15:42, Tony Dinh <mibodhi at gmail.com> wrote:
>
> Use CONFIG_CONSOLE_MUX for netconsole. When netconsole is running,
> stdin/stdout/stder must be set to some primary console, in addtion to nc.
> For example, stdin=serial,nc. Some recent Linux kernels will not boot with
> only nc on the stdout list, ie. stdout=nc. When netconsole exits, remove
> nc from the list of devices in stdin/stdout/stderr.
>
> Signed-off-by: Tony Dinh <mibodhi at gmail.com>
> ---
>
> Changes in v2:
> - Select CONFIG_CONSOLE_MUX if CONFIG_NETCONSOLE is enabled
> - Add new functions in netconsole driver to support CONSOLE_MUX
> - Add new function to encapsulate the process of stopping netconsole
> from bootm
> - Remove unecessary net_timeout initial value = 1
> - Resend to correct missing <stdio_dev.h> include in bootm.c
>
> boot/bootm.c | 14 +++++++---
> drivers/net/Kconfig | 10 +++++++
> drivers/net/netconsole.c | 60 ++++++++++++++++++++++++++++++++++++++++
> include/stdio_dev.h | 1 +
> 4 files changed, 81 insertions(+), 4 deletions(-)
This seems OK to me but for a few thoughts below.
But can we use this opportunity to move this to driver model? The
netconsole driver could be bound in eth_post_bind() and the code in
netconsole.c converted to be a driver.
I think that would be better than building on an out-of-date driver.
>
> diff --git a/boot/bootm.c b/boot/bootm.c
> index 2eec60ec7b..1b2542b570 100644
> --- a/boot/bootm.c
> +++ b/boot/bootm.c
> @@ -18,6 +18,7 @@
> #include <malloc.h>
> #include <mapmem.h>
> #include <net.h>
> +#include <stdio_dev.h>
> #include <asm/cache.h>
> #include <asm/global_data.h>
> #include <asm/io.h>
> @@ -472,11 +473,16 @@ ulong bootm_disable_interrupts(void)
> * recover from any failures any more...
> */
> iflag = disable_interrupts();
> -#ifdef CONFIG_NETCONSOLE
> - /* Stop the ethernet stack if NetConsole could have left it up */
> - eth_halt();
> -#endif
>
> + if (IS_ENABLED(CONFIG_NETCONSOLE)) {
> + /*
> + * Make sure that the starting kernel message printed out,
> + * stop netconsole and the ethernet stack
> + */
> + printf("\n\nStarting kernel ...\n\n");
> + drv_nc_stop();
> + eth_halt();
> + }
> #if defined(CONFIG_CMD_USB)
> /*
> * turn off USB to prevent the host controller from writing to the
> diff --git a/drivers/net/Kconfig b/drivers/net/Kconfig
> index ceadee98a1..0661059dfa 100644
> --- a/drivers/net/Kconfig
> +++ b/drivers/net/Kconfig
> @@ -945,4 +945,14 @@ config MDIO_MUX_MESON_G12A
> This driver is used for the MDIO mux found on the Amlogic G12A & compatible
> SoCs.
>
> +config NETCONSOLE
> + bool "Enable netconsole"
> + select CONSOLE_MUX
> + help
> + NetConsole requires CONSOLE_MUX, i.e. at least one default console such
> + must be specified in addition to nc console. For example, for boards that
> + the main console is serial, set each of the envs stdin/stdout/stderr to serial,nc.
> + See CONFIG_CONSOLE_MUX and CONFIG_SYS_CONSOLE_IS_IN_ENV help for detailed
> + description of usage.
> +
> endif # NETDEVICES
> diff --git a/drivers/net/netconsole.c b/drivers/net/netconsole.c
> index 151bc55e07..bb92d2e130 100644
> --- a/drivers/net/netconsole.c
> +++ b/drivers/net/netconsole.c
> @@ -7,6 +7,7 @@
> #include <common.h>
> #include <command.h>
> #include <env.h>
> +#include <iomux.h>
> #include <log.h>
> #include <stdio_dev.h>
> #include <net.h>
> @@ -33,6 +34,12 @@ static int output_packet_len;
> */
> enum proto_t net_loop_last_protocol = BOOTP;
>
> +/*
> + * Net console helpers
> + */
> +static void usage(void);
> +static void remove_nc_from(const int console);
> +
> static void nc_wait_arp_handler(uchar *pkt, unsigned dest,
> struct in_addr sip, unsigned src,
> unsigned len)
> @@ -111,6 +118,21 @@ static int refresh_settings_from_env(void)
> return 0;
> }
>
> +static void remove_nc_from(const int console)
> +{
> + int ret;
> +
> + ret = iomux_replace_device(console, "nc", "nulldev");
> + if (ret) {
> + printf("\n*** Warning: Cannot remove nc from %s Error=%d\n",
> + stdio_names[console], ret);
> + printf("%s=", stdio_names[console]);
> + iomux_printdevs(console);
> + usage();
> + flush();
> + }
> +}
> +
> /**
> * Called from net_loop in net/net.c before each packet
> */
> @@ -241,6 +263,29 @@ static int nc_stdio_start(struct stdio_dev *dev)
> return 0;
> }
>
> +void nc_stdio_stop(void)
> +{
> + if (IS_ENABLED(CONFIG_CONSOLE_MUX)) {
> + int ret;
> + struct stdio_dev *sdev;
> +
> + /* Remove nc from each stdio file */
> + remove_nc_from(stdin);
> + remove_nc_from(stderr);
> + remove_nc_from(stdout);
> +
> + /* Deregister nc device */
> + sdev = stdio_get_by_name("nc");
> + ret = stdio_deregister_dev(sdev, true);
> + if (ret)
> + printf("\nWarning: Cannot deregister nc console Error=%d\n", ret);
> + } else {
> + printf("\n*** Warning: CONFIG_CONSOLE_MUX must be enabled for netconsole\n"
> + "to work properly. The nc console will be removed when\n"
> + "netconsole driver stops\n");
> + }
> +}
> +
> static void nc_stdio_putc(struct stdio_dev *dev, char c)
> {
> if (output_recursion)
> @@ -316,6 +361,16 @@ static int nc_stdio_tstc(struct stdio_dev *dev)
> return input_size != 0;
> }
>
> +static void usage(void)
> +{
> + printf("USAGE:\n"
> + "NetConsole requires CONFIG_CONSOLE_MUX. At least one default console\n"
> + "must be specified in addition to nc console. For example, for boards\n"
> + "that the main console is serial, set the each of envs stdin/stdout/stderr\n"
> + "to serial,nc. Some kernel might fail to boot when nc is the only device in\n"
> + "stdout list\n");
How about creating a doc/ file with info about net console? This is a
bit too much text to put in a user message.
> +}
> +
> int drv_nc_init(void)
> {
> struct stdio_dev dev;
> @@ -335,3 +390,8 @@ int drv_nc_init(void)
>
> return (rc == 0) ? 1 : rc;
> }
> +
> +void drv_nc_stop(void)
> +{
> + nc_stdio_stop();
> +}
> diff --git a/include/stdio_dev.h b/include/stdio_dev.h
> index 3105928970..9d2375a67e 100644
> --- a/include/stdio_dev.h
> +++ b/include/stdio_dev.h
> @@ -112,6 +112,7 @@ int drv_keyboard_init(void);
> int drv_usbtty_init(void);
> int drv_usbacm_init(void);
> int drv_nc_init(void);
> +void drv_nc_stop(void);
Once this is a driver we won't need this.
> int drv_jtag_console_init(void);
> int cbmemc_init(void);
Regards,
Simon
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