nvram_read
ssize_t (*nvram_read)(char *buf, size_t count, loff_t *index);
err = ppc_md.nvram_read(header, NVRAM_HEADER_LEN, &cur_index);
rc = ppc_md.nvram_read((char *)&info, sizeof(info), &tmp_index);
rc = ppc_md.nvram_read(buff, length, &tmp_index);
ppc_md.nvram_read = core99_nvram_read;
ppc_md.nvram_read = opal_nvram_read;
ppc_md.nvram_read = pSeries_nvram_read;
ppc_md.nvram_read = mmio_nvram_read;
ret = nvram_read(tmp, count, ppos);
ssize_t count = nvram_read(&b, 1, &offset);
if (ppc_md.nvram_read)
return ppc_md.nvram_read(buf, count, ppos);