This patch implements simple hwconfig infrastructure: an interface for software knobs to control a hardware.
This is very simple implementation, i.e. it is implemented via `hwconfig' environment variable. Later we could write some "hwconfig <enable|disable|list>" commands, ncurses interface for Award BIOS-like interface, and frame-buffer interface for AMI GUI[1] BIOS-like interface with mouse support[2].
Current implementation details/limitations:
1. Doesn't support options dependencies and mutual exclusion. We can implement this by integrating apt-get[3] into the u-boot. But I didn't bother yet.
2. Since we don't implement hwconfig command, i.e. we're working with the environement directly, there is no way to tell that toggling a particular option will need a reboot to take an effect. So, for now it's advised to always reboot the target after modifying hwconfig variable.
3. We support hwconfig options with arguments. For example,
set hwconfig dr_usb,dr_usb_mode:peripheral,dr_usb_phy_type:ulpi
There are three hwconfig options selected: 1. dr_usb - enable Dual-Role USB controller; 2. dr_usb_mode:peripheral - USB in Function mode; 3. dr_usb_phy_type:ulpi - USB should work with ULPI PHYs.
The purpose of this simple implementation is to define some internal API and then we can continue improving user experience by adding more mature interface, like hwconfig command with bells and whistles. Or not adding, if we feel that current interface fits its needs.
[1] http://en.wikipedia.org/wiki/American_Megatrends [2] Regarding ncurses and GUI with mouse support -- I'm just kidding. [3] The comment regarding apt-get is also a joke, meaning that dependency tracking could be non-trivial. For example, for enabling HW feature X we may need to disable Y, and turn Z into reduced mode (like RMII-only interface for ethernet, no MII).
It's quite trivial to implement simple cases though.
Signed-off-by: Anton Vorontsov avorontsov@ru.mvista.com --- common/Makefile | 1 + common/hwconfig.c | 134 ++++++++++++++++++++++++++++++++++++++++++++++++++++ include/hwconfig.h | 46 ++++++++++++++++++ 3 files changed, 181 insertions(+), 0 deletions(-) create mode 100644 common/hwconfig.c create mode 100644 include/hwconfig.h
diff --git a/common/Makefile b/common/Makefile index b9f4ca7..41d6b3d 100644 --- a/common/Makefile +++ b/common/Makefile @@ -150,6 +150,7 @@ COBJS-$(CONFIG_VFD) += cmd_vfd.o # others COBJS-$(CONFIG_DDR_SPD) += ddr_spd.o COBJS-$(CONFIG_CMD_DOC) += docecc.o +COBJS-$(CONFIG_HWCONFIG) += hwconfig.o COBJS-$(CONFIG_CONSOLE_MUX) += iomux.o COBJS-y += flash.o COBJS-$(CONFIG_CMD_KGDB) += kgdb.o diff --git a/common/hwconfig.c b/common/hwconfig.c new file mode 100644 index 0000000..c9a6712 --- /dev/null +++ b/common/hwconfig.c @@ -0,0 +1,134 @@ +/* + * An inteface for configuring a hardware via u-boot environment. + * + * Copyright (c) 2009 MontaVista Software, Inc. + * + * Author: Anton Vorontsov avorontsov@ru.mvista.com + * + * 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 (at your option) any later version. + */ + +#include <config.h> +#include <exports.h> +#include <hwconfig.h> +#include <linux/types.h> +#include <linux/string.h> + +static const char *hwconfig_parse(const char *opts, const char *opt, + size_t *arglen) +{ + size_t optlen = strlen(opt); + char *str = strstr(opts, opt); + const char *end = str + optlen; + + if (str && (str == opts || str[-1] == ',' ) && + (*end == ',' || *end == ':' || *end == '\0')) { + const char *arg_end; + + if (!arglen) + return str; + + if (*end != ':') + return NULL; + + arg_end = strchr(str, ','); + if (!arg_end) + *arglen = strlen(str) - optlen - 1; + else + *arglen = arg_end - end - 1; + + return end + 1; + } + return NULL; +} + +const char *cpu_hwconfig __attribute__((weak)); +const char *board_hwconfig __attribute__((weak)); + +static const char *__hwconfig(const char *opt, size_t *arglen) +{ + const char *env_hwconfig = getenv("hwconfig"); + + if (env_hwconfig) + return hwconfig_parse(env_hwconfig, opt, arglen); + + if (board_hwconfig) + return hwconfig_parse(board_hwconfig, opt, arglen); + + if (cpu_hwconfig) + return hwconfig_parse(cpu_hwconfig, opt, arglen); + + return NULL; +} + +/* + * hwconfig - query if a particular hardware option should be used + * @opt: a string representing an option + * + * This call can be used to find out whether U-Boot should configure + * a particular hardware option. + * + * Returns non-zero value if the hardware option can be used and thus + * should be configured, 0 otherwise. + * + * This function also returns non-zero value if CONFIG_HWCONFIG is + * undefined. + * + * Returning non-zero value without CONFIG_HWCONFIG has its crucial + * purpose: the hwconfig() call should be a "transparent" interface, + * e.g. if a board doesn't need hwconfig facility, then we assume + * that the board file only calls things that are actually used, so + * hwconfig() will always return true result. + */ +int hwconfig(const char *opt) +{ + return !!__hwconfig(opt, NULL); +} + +/* + * hwconfig_arg - query if a particular hardware option should be used + * @opt: a string representing an option + * @arglen: a pointer to an allocated size_t variable + * + * This call can be used to find out whether U-Boot should configure + * a particular hardware option. + * + * Unlike hwconfig() function, this function returns a pointer to the + * start of the hwconfig arguments, if option is not found or it has + * no specified arguments, the function returns NULL pointer. + * + * If CONFIG_HWCONFIG is undefined, the function returns "", and + * arglen is set to 0. + */ +const char *hwconfig_arg(const char *opt, size_t *arglen) +{ + return __hwconfig(opt, arglen); +} + +/* + * hwconfig_arg_cmp - compare hwconfig's arguments + * @opt: a string representing an option + * @arg: a string for comparing an option's argument + * + * This call is similar to hwconfig_arg, but instead of returning + * hwconfig argument and its length, it is comparing it to @arg. + * + * Returns 1 if @arg matches, 0 otherwise. + * + * If CONFIG_HWCONFIG is undefined, the function returns 1, i.e. + * the argument matches. + */ +int hwconfig_arg_cmp(const char *opt, const char *arg) +{ + const char *argstr; + size_t arglen; + + argstr = hwconfig_arg(opt, &arglen); + if (!argstr) + return 0; + + return !strncmp(argstr, arg, arglen + 1); +} diff --git a/include/hwconfig.h b/include/hwconfig.h new file mode 100644 index 0000000..704086a --- /dev/null +++ b/include/hwconfig.h @@ -0,0 +1,46 @@ +/* + * An inteface for configuring a hardware via u-boot environment. + * + * Copyright (c) 2009 MontaVista Software, Inc. + * + * Author: Anton Vorontsov avorontsov@ru.mvista.com + * + * 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 (at your option) any later version. + */ + +#ifndef _HWCONFIG_H +#define _HWCONFIG_H + +#include <linux/types.h> +#include <asm/errno.h> + +#ifdef CONFIG_HWCONFIG + +extern int hwconfig(const char *opt); +extern const char *hwconfig_arg(const char *opt, size_t *arglen); +extern int hwconfig_arg_cmp(const char *opt, const char *arg); + +#else + +static inline int hwconfig(const char *opt) +{ + return -ENOSYS; +} + +static inline const char *hwconfig_arg(const char *opt, size_t *arglen) +{ + *arglen = 0; + return ""; +} + +static inline int hwconfig_arg_cmp(const char *opt, const char *arg) +{ + return 0; +} + +#endif /* CONFIG_HWCONFIG */ + +#endif /* _HWCONFIG_H */