diff options
Diffstat (limited to 'target/linux/brcm47xx/files-2.6.28/arch/mips/bcm47xx/cfe_env.c')
-rw-r--r-- | target/linux/brcm47xx/files-2.6.28/arch/mips/bcm47xx/cfe_env.c | 229 |
1 files changed, 229 insertions, 0 deletions
diff --git a/target/linux/brcm47xx/files-2.6.28/arch/mips/bcm47xx/cfe_env.c b/target/linux/brcm47xx/files-2.6.28/arch/mips/bcm47xx/cfe_env.c new file mode 100644 index 0000000..c1d5eee --- /dev/null +++ b/target/linux/brcm47xx/files-2.6.28/arch/mips/bcm47xx/cfe_env.c @@ -0,0 +1,229 @@ +/* + * CFE environment variable access + * + * Copyright 2001-2003, Broadcom Corporation + * Copyright 2006, Felix Fietkau <nbd@openwrt.org> + * + * 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 <linux/init.h> +#include <linux/module.h> +#include <linux/kernel.h> +#include <linux/string.h> +#include <asm/io.h> +#include <asm/uaccess.h> + +#define NVRAM_SIZE (0x1ff0) +static char _nvdata[NVRAM_SIZE]; +static char _valuestr[256]; + +/* + * TLV types. These codes are used in the "type-length-value" + * encoding of the items stored in the NVRAM device (flash or EEPROM) + * + * The layout of the flash/nvram is as follows: + * + * <type> <length> <data ...> <type> <length> <data ...> <type_end> + * + * The type code of "ENV_TLV_TYPE_END" marks the end of the list. + * The "length" field marks the length of the data section, not + * including the type and length fields. + * + * Environment variables are stored as follows: + * + * <type_env> <length> <flags> <name> = <value> + * + * If bit 0 (low bit) is set, the length is an 8-bit value. + * If bit 0 (low bit) is clear, the length is a 16-bit value + * + * Bit 7 set indicates "user" TLVs. In this case, bit 0 still + * indicates the size of the length field. + * + * Flags are from the constants below: + * + */ +#define ENV_LENGTH_16BITS 0x00 /* for low bit */ +#define ENV_LENGTH_8BITS 0x01 + +#define ENV_TYPE_USER 0x80 + +#define ENV_CODE_SYS(n,l) (((n)<<1)|(l)) +#define ENV_CODE_USER(n,l) ((((n)<<1)|(l)) | ENV_TYPE_USER) + +/* + * The actual TLV types we support + */ + +#define ENV_TLV_TYPE_END 0x00 +#define ENV_TLV_TYPE_ENV ENV_CODE_SYS(0,ENV_LENGTH_8BITS) + +/* + * Environment variable flags + */ + +#define ENV_FLG_NORMAL 0x00 /* normal read/write */ +#define ENV_FLG_BUILTIN 0x01 /* builtin - not stored in flash */ +#define ENV_FLG_READONLY 0x02 /* read-only - cannot be changed */ + +#define ENV_FLG_MASK 0xFF /* mask of attributes we keep */ +#define ENV_FLG_ADMIN 0x100 /* lets us internally override permissions */ + + +/* ********************************************************************* + * _nvram_read(buffer,offset,length) + * + * Read data from the NVRAM device + * + * Input parameters: + * buffer - destination buffer + * offset - offset of data to read + * length - number of bytes to read + * + * Return value: + * number of bytes read, or <0 if error occured + ********************************************************************* */ +static int +_nvram_read(unsigned char *nv_buf, unsigned char *buffer, int offset, int length) +{ + int i; + if (offset > NVRAM_SIZE) + return -1; + + for ( i = 0; i < length; i++) { + buffer[i] = ((volatile unsigned char*)nv_buf)[offset + i]; + } + return length; +} + + +static char* +_strnchr(const char *dest,int c,size_t cnt) +{ + while (*dest && (cnt > 0)) { + if (*dest == c) return (char *) dest; + dest++; + cnt--; + } + return NULL; +} + + + +/* + * Core support API: Externally visible. + */ + +/* + * Get the value of an NVRAM variable + * @param name name of variable to get + * @return value of variable or NULL if undefined + */ + +char* +cfe_env_get(unsigned char *nv_buf, char* name) +{ + int size; + unsigned char *buffer; + unsigned char *ptr; + unsigned char *envval; + unsigned int reclen; + unsigned int rectype; + int offset; + int flg; + + if (!strcmp(name, "nvram_type")) + return "cfe"; + + size = NVRAM_SIZE; + buffer = &_nvdata[0]; + + ptr = buffer; + offset = 0; + + /* Read the record type and length */ + if (_nvram_read(nv_buf, ptr,offset,1) != 1) { + goto error; + } + + while ((*ptr != ENV_TLV_TYPE_END) && (size > 1)) { + + /* Adjust pointer for TLV type */ + rectype = *(ptr); + offset++; + size--; + + /* + * Read the length. It can be either 1 or 2 bytes + * depending on the code + */ + if (rectype & ENV_LENGTH_8BITS) { + /* Read the record type and length - 8 bits */ + if (_nvram_read(nv_buf, ptr,offset,1) != 1) { + goto error; + } + reclen = *(ptr); + size--; + offset++; + } + else { + /* Read the record type and length - 16 bits, MSB first */ + if (_nvram_read(nv_buf, ptr,offset,2) != 2) { + goto error; + } + reclen = (((unsigned int) *(ptr)) << 8) + (unsigned int) *(ptr+1); + size -= 2; + offset += 2; + } + + if (reclen > size) + break; /* should not happen, bad NVRAM */ + + switch (rectype) { + case ENV_TLV_TYPE_ENV: + /* Read the TLV data */ + if (_nvram_read(nv_buf, ptr,offset,reclen) != reclen) + goto error; + flg = *ptr++; + envval = (unsigned char *) _strnchr(ptr,'=',(reclen-1)); + if (envval) { + *envval++ = '\0'; + memcpy(_valuestr,envval,(reclen-1)-(envval-ptr)); + _valuestr[(reclen-1)-(envval-ptr)] = '\0'; +#if 0 + printk(KERN_INFO "NVRAM:%s=%s\n", ptr, _valuestr); +#endif + if(!strcmp(ptr, name)){ + return _valuestr; + } + if((strlen(ptr) > 1) && !strcmp(&ptr[1], name)) + return _valuestr; + } + break; + + default: + /* Unknown TLV type, skip it. */ + break; + } + + /* + * Advance to next TLV + */ + + size -= (int)reclen; + offset += reclen; + + /* Read the next record type */ + ptr = buffer; + if (_nvram_read(nv_buf, ptr,offset,1) != 1) + goto error; + } + +error: + return NULL; + +} + |