linux_kernel/drivers/net/wireless/brcm80211/brcmfmac/nvram.c

/*
 * Copyright (c) 2013 Broadcom Corporation
 *
 * Permission to use, copy, modify, and/or distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice and this permission notice appear in all copies.
 *
 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
 * SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION
 * OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN
 * CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 */

#include <linux/kernel.h>
#include <linux/slab.h>
#include <linux/firmware.h>

#include "nvram.h"

/* brcmf_nvram_strip :Takes a buffer of "<var>=<value>\n" lines read from a file
 * and ending in a NUL. Removes carriage returns, empty lines, comment lines,
 * and converts newlines to NULs. Shortens buffer as needed and pads with NULs.
 * End of buffer is completed with token identifying length of buffer.
 */
void *brcmf_nvram_strip(const struct firmware *nv, u32 *new_length)
{
	u8 *nvram;
	u32 i;
	u32 len;
	u32 column;
	u8 val;
	bool comment;
	u32 token;
	__le32 token_le;

	/* Alloc for extra 0 byte + roundup by 4 + length field */
	nvram = kmalloc(nv->size + 1 + 3 + sizeof(token_le), GFP_KERNEL);
	if (!nvram)
		return NULL;

	len = 0;
	column = 0;
	comment = false;
	for (i = 0; i < nv->size; i++) {
		val = nv->data[i];
		if (val == 0)
			break;
		if (val == '\r')
			continue;
		if (comment && (val != '\n'))
			continue;
		comment = false;
		if (val == '#') {
			comment = true;
			continue;
		}
		if (val == '\n') {
			if (column == 0)
				continue;
			nvram[len] = 0;
			len++;
			column = 0;
			continue;
		}
		nvram[len] = val;
		len++;
		column++;
	}
	column = len;
	*new_length = roundup(len + 1, 4);
	while (column != *new_length) {
		nvram[column] = 0;
		column++;
	}

	token = *new_length / 4;
	token = (~token << 16) | (token & 0x0000FFFF);
	token_le = cpu_to_le32(token);

	memcpy(&nvram[*new_length], &token_le, sizeof(token_le));
	*new_length += sizeof(token_le);

	return nvram;
}

void brcmf_nvram_free(void *nvram)
{
	kfree(nvram);
}