Fix rc4 compiler warning

cmd/Makefile

@@ -148,6 +148,8 @@ obj-$(CONFIG_CMD_DFU) += dfu.o
 obj-$(CONFIG_CMD_GPT) += gpt.o
 obj-$(CONFIG_CMD_ETHSW) += ethsw.o
 
+obj-$(CONFIG_CMD_RC4) += rc4.o
+
 # Power
 obj-$(CONFIG_CMD_PMIC) += pmic.o
 obj-$(CONFIG_CMD_REGULATOR) += regulator.o

cmd/rc4.c

@@ -0,0 +1,123 @@
+/* Copyright 2012
+ * Jaap de Jong, [email protected]
+ *
+ * See file CREDITS for list of people who contributed to this
+ * project.
+ *
+ * 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.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
+ * MA 02111-1307 USA
+ */
+
+#include <common.h>
+#include <command.h>
+#include <asm/arch/at91_pio.h>
+#include <watchdog.h>
+
+#ifdef CONFIG_CMD_RC4
+
+typedef struct rc4_state {
+	u_char	perm[256];
+	u_char	index1;
+	u_char	index2;
+} rc4_state;
+
+#define swap_bytes(a, b) { temp = *a; *a = *b; *b = temp; }
+
+/*
+ * Initialize an RC4 state buffer using the supplied key,
+ * which can have arbitrary length.
+ */
+void rc4_init(rc4_state *state, const u_char *key, int keylen)
+{
+	int i;
+	u_char j = 0;
+	u_char temp;
+
+	/* Initialize state with identity permutation */
+	for (i = 0; i < 256; i++)
+		state->perm[i] = (u_char) i;
+	state->index1 = 0;
+	state->index2 = 0;
+
+	/* Randomize the permutation using key data */
+	for (i = 0; i < 256; i++) {
+		j += state->perm[i] + key[i % keylen];
+		swap_bytes(&state->perm[i], &state->perm[j]);
+	}
+}
+
+/*
+ * Encrypt some data using the supplied RC4 state buffer.
+ * The input and output buffers may be the same buffer.
+ * Since RC4 is a stream cypher, this function is used
+ * for both encryption and decryption.
+ */
+void rc4_crypt(rc4_state *state, u_char *buf, long buflen)
+{
+	u_char	j;
+	u_char temp;
+
+	while (buflen--) {
+
+		/* Update modification indicies */
+		state->index1++;
+		state->index2 += state->perm[state->index1];
+
+		/* Modify permutation */
+		swap_bytes(&state->perm[state->index1], &state->perm[state->index2]);
+
+		/* Encrypt/decrypt next byte */
+		j = state->perm[state->index1] + state->perm[state->index2];
+		*(buf++) ^= state->perm[j];
+
+		/* watchdog... */
+		if ((buflen & 0x7fffff) == 0) {
+			WATCHDOG_RESET();
+		}
+	}
+}
+
+/*
+ * handle the command.
+ */
+int cmd_rc4 (cmd_tbl_t * cmdtp, int flag, int argc, char * const argv[])
+{
+	unsigned long size = 0;
+	u_char *addr;
+	rc4_state state;
+	u_char key[] = {0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08, 0x09, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f};
+
+	if (argc != 3) return cmd_usage(cmdtp);
+
+	addr = (u_char *)simple_strtoul(argv[1], NULL, 16);
+	size = simple_strtoul(argv[2], NULL, 16);
+
+	rc4_init(&state, key, sizeof(key));
+	rc4_crypt(&state, addr, size);
+
+	return 0;
+}
+
+U_BOOT_CMD (rc4, 3, 1, cmd_rc4,
+	"encrypt/decrypt memory",
+	"rc4 <addr> <size>\n"
+	"	- example:\n"
+	"	-	run kernel_ubi_read\n"
+	"	-	ubifsload 0x70000000 /flash/ubifilesystem.bin\n"
+	"	-	rc4 0x70000000 ${filesize}\n"
+	"	-	nand erase 0x00000000 0x00020000\n"
+	"	-	nand write 0x70000600 0x00000000 0x00020000");
+
+#endif