++#define NVRAM_SIZE (0x1ff0)
++static char _nvdata[NVRAM_SIZE] __initdata;
++static char _valuestr[256] __initdata;
++
++/*
++ * 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;
++
++ 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;
++
++}