u-boot/common/hwconfig.c
Kumar Gala c4b115f536 hwconfig: Utilize getenv_f before relocation to allow for larger buffer
Since we use hwconfig in cases before relocation (like getting DDR
params on FSL PPC systems), we can have strings that exceed the early
small (32 byte) buffer size that getenv will handle.

So we explicitly allocate our own buffer on the stack and use if to
handle getting the hwconfig env string.  We currently utilize a string
length of 128 bytes.

This allows us to get rid of boot messages like:

env_buf too small [32]

Signed-off-by: Kumar Gala <galak@kernel.crashing.org>
2010-10-23 22:10:54 +02:00

285 lines
7.6 KiB
C

/*
* 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_TEST
#include <config.h>
#include <common.h>
#include <exports.h>
#include <hwconfig.h>
#include <linux/types.h>
#include <linux/string.h>
#else
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <assert.h>
#define min(a, b) (((a) < (b)) ? (a) : (b))
#endif /* HWCONFIG_TEST */
DECLARE_GLOBAL_DATA_PTR;
static const char *hwconfig_parse(const char *opts, size_t maxlen,
const char *opt, char *stopchs, char eqch,
size_t *arglen)
{
size_t optlen = strlen(opt);
char *str;
const char *start = opts;
const char *end;
next:
str = strstr(opts, opt);
end = str + optlen;
if (end - start > maxlen)
return NULL;
if (str && (str == opts || strpbrk(str - 1, stopchs) == str - 1) &&
(strpbrk(end, stopchs) == end || *end == eqch ||
*end == '\0')) {
const char *arg_end;
if (!arglen)
return str;
if (*end != eqch)
return NULL;
arg_end = strpbrk(str, stopchs);
if (!arg_end)
*arglen = min(maxlen, strlen(str)) - optlen - 1;
else
*arglen = arg_end - end - 1;
return end + 1;
} else if (str) {
opts = end;
goto next;
}
return NULL;
}
const char *cpu_hwconfig __attribute__((weak));
const char *board_hwconfig __attribute__((weak));
#define HWCONFIG_PRE_RELOC_BUF_SIZE 128
static const char *__hwconfig(const char *opt, size_t *arglen)
{
const char *env_hwconfig = NULL;
char buf[HWCONFIG_PRE_RELOC_BUF_SIZE];
if (gd->flags & GD_FLG_ENV_READY) {
env_hwconfig = getenv("hwconfig");
} else {
/*
* Use our own on stack based buffer before relocation to allow
* accessing longer hwconfig strings that might be in the
* environment before we've relocated. This is pretty fragile
* on both the use of stack and if the buffer is big enough.
* However we will get a warning from getenv_f for the later.
*/
if ((getenv_f("hwconfig", buf, sizeof(buf))) > 0)
env_hwconfig = buf;
}
if (env_hwconfig)
return hwconfig_parse(env_hwconfig, strlen(env_hwconfig),
opt, ";", ':', arglen);
if (board_hwconfig)
return hwconfig_parse(board_hwconfig, strlen(board_hwconfig),
opt, ";", ':', arglen);
if (cpu_hwconfig)
return hwconfig_parse(cpu_hwconfig, strlen(cpu_hwconfig),
opt, ";", ':', arglen);
return NULL;
}
/*
* hwconfig - query if a particular hwconfig option is specified
* @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 - get hwconfig option's argument
* @opt: a string representing an option
* @arglen: a pointer to an allocated size_t variable
*
* 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 option's argument
* @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 non-zero value if @arg matches, 0 otherwise.
*
* If CONFIG_HWCONFIG is undefined, the function returns a non-zero
* value, 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 || arglen != strlen(arg))
return 0;
return !strncmp(argstr, arg, arglen);
}
/*
* hwconfig_sub - query if a particular hwconfig sub-option is specified
* @opt: a string representing an option
* @subopt: a string representing a sub-option
*
* This call is similar to hwconfig(), except that it takes additional
* argument @subopt. In this example:
* "dr_usb:mode=peripheral"
* "dr_usb" is an option, "mode" is a sub-option, and "peripheral" is its
* argument.
*/
int hwconfig_sub(const char *opt, const char *subopt)
{
size_t arglen;
const char *arg;
arg = __hwconfig(opt, &arglen);
if (!arg)
return 0;
return !!hwconfig_parse(arg, arglen, subopt, ",;", '=', NULL);
}
/*
* hwconfig_subarg - get hwconfig sub-option's argument
* @opt: a string representing an option
* @subopt: a string representing a sub-option
* @subarglen: a pointer to an allocated size_t variable
*
* This call is similar to hwconfig_arg(), except that it takes an additional
* argument @subopt, and so works with sub-options.
*/
const char *hwconfig_subarg(const char *opt, const char *subopt,
size_t *subarglen)
{
size_t arglen;
const char *arg;
arg = __hwconfig(opt, &arglen);
if (!arg)
return NULL;
return hwconfig_parse(arg, arglen, subopt, ",;", '=', subarglen);
}
/*
* hwconfig_arg_cmp - compare hwconfig sub-option's argument
* @opt: a string representing an option
* @subopt: a string representing a sub-option
* @subarg: a string for comparing an sub-option's argument
*
* This call is similar to hwconfig_arg_cmp, except that it takes an additional
* argument @subopt, and so works with sub-options.
*/
int hwconfig_subarg_cmp(const char *opt, const char *subopt, const char *subarg)
{
const char *argstr;
size_t arglen;
argstr = hwconfig_subarg(opt, subopt, &arglen);
if (!argstr || arglen != strlen(subarg))
return 0;
return !strncmp(argstr, subarg, arglen);
}
#ifdef HWCONFIG_TEST
int main()
{
const char *ret;
size_t len;
setenv("hwconfig", "key1:subkey1=value1,subkey2=value2;key2:value3;;;;"
"key3;:,:=;key4", 1);
ret = hwconfig_arg("key1", &len);
printf("%zd %.*s\n", len, (int)len, ret);
assert(len == 29);
assert(hwconfig_arg_cmp("key1", "subkey1=value1,subkey2=value2"));
assert(!strncmp(ret, "subkey1=value1,subkey2=value2", len));
ret = hwconfig_subarg("key1", "subkey1", &len);
printf("%zd %.*s\n", len, (int)len, ret);
assert(len == 6);
assert(hwconfig_subarg_cmp("key1", "subkey1", "value1"));
assert(!strncmp(ret, "value1", len));
ret = hwconfig_subarg("key1", "subkey2", &len);
printf("%zd %.*s\n", len, (int)len, ret);
assert(len == 6);
assert(hwconfig_subarg_cmp("key1", "subkey2", "value2"));
assert(!strncmp(ret, "value2", len));
ret = hwconfig_arg("key2", &len);
printf("%zd %.*s\n", len, (int)len, ret);
assert(len == 6);
assert(hwconfig_arg_cmp("key2", "value3"));
assert(!strncmp(ret, "value3", len));
assert(hwconfig("key3"));
assert(hwconfig_arg("key4", &len) == NULL);
assert(hwconfig_arg("bogus", &len) == NULL);
unsetenv("hwconfig");
assert(hwconfig(NULL) == 0);
assert(hwconfig("") == 0);
assert(hwconfig("key3") == 0);
return 0;
}
#endif /* HWCONFIG_TEST */