Import the ethernet MAC setting tool for Snowball

This tool allows one to change (permanently) the MAC address
of the SMSC 9221 Ethernet controller of Snowball boards.

The address is written to the EEPROM of the controller to persist
over reboots.

1 files changed, 229 insertions, 0 deletions

diff --git a/newmac.c b/newmac.c
new file mode 100644
index 0000000..0a9d2e1
--- /dev/null
+++ b/newmac.c
@@ -0,0 +1,229 @@
+/*

+ * Write a new mac address in the snowball device.

+ * This programs the 9221 Ethernet device mapped at 0x5000.0000 on 16 bits.

+ * Note that you must have the ethernet down during this operation.

+ *

+ * Alessandro Rubini, 2011 (under contract with ST-Ericsson AG)

+ * GNU GPL v2 or later.

+ */

+#include <stdio.h>

+#include <stdlib.h>

+#include <unistd.h>

+#include <string.h>

+#include <errno.h>

+#include <signal.h>

+#include <fcntl.h>

+#include <ctype.h>

+#include <termios.h>

+#include <sys/types.h>

+#include <sys/mman.h>

+

+/*

+ * Lazily, copy fnames from drivers/net/smsc911x.h

+ */

+#define GPIO_CFG			0x88

+#define GPIO_CFG_LED3_EN_		0x40000000

+#define GPIO_CFG_LED2_EN_		0x20000000

+#define GPIO_CFG_LED1_EN_		0x10000000

+#define GPIO_CFG_GPIO2_INT_POL_		0x04000000

+#define GPIO_CFG_GPIO1_INT_POL_		0x02000000

+#define GPIO_CFG_GPIO0_INT_POL_		0x01000000

+#define GPIO_CFG_EEPR_EN_		0x00700000

+#define GPIO_CFG_GPIOBUF2_		0x00040000

+#define GPIO_CFG_GPIOBUF1_		0x00020000

+#define GPIO_CFG_GPIOBUF0_		0x00010000

+#define GPIO_CFG_GPIODIR2_		0x00000400

+#define GPIO_CFG_GPIODIR1_		0x00000200

+#define GPIO_CFG_GPIODIR0_		0x00000100

+#define GPIO_CFG_GPIOD4_		0x00000020

+#define GPIO_CFG_GPIOD3_		0x00000010

+#define GPIO_CFG_GPIOD2_		0x00000004

+#define GPIO_CFG_GPIOD1_		0x00000002

+#define GPIO_CFG_GPIOD0_		0x00000001

+

+#define E2P_CMD				0xB0

+#define E2P_CMD_EPC_BUSY_		0x80000000

+#define E2P_CMD_EPC_CMD_		0x70000000

+#define E2P_CMD_EPC_CMD_READ_		0x00000000

+#define E2P_CMD_EPC_CMD_EWDS_		0x10000000

+#define E2P_CMD_EPC_CMD_EWEN_		0x20000000

+#define E2P_CMD_EPC_CMD_WRITE_		0x30000000

+#define E2P_CMD_EPC_CMD_WRAL_		0x40000000

+#define E2P_CMD_EPC_CMD_ERASE_		0x50000000

+#define E2P_CMD_EPC_CMD_ERAL_		0x60000000

+#define E2P_CMD_EPC_CMD_RELOAD_		0x70000000

+#define E2P_CMD_EPC_TIMEOUT_		0x00000200

+#define E2P_CMD_MAC_ADDR_LOADED_	0x00000100

+#define E2P_CMD_EPC_ADDR_		0x000000FF

+

+#define E2P_DATA			0xB4

+#define E2P_DATA_EEPROM_DATA_		0x000000FF

+

+

+#define FATAL do { fprintf(stderr, "Error at line %d, file %s (%d) [%s]\n", \

+  __LINE__, __FILE__, errno, strerror(errno)); exit(1); } while(0)

+

+#define MAP_BASE 0x50000000

+#define MAP_SIZE 0x00001000 /* 4k */

+

+static void reg_w(void *base, int reg, unsigned long val)

+{

+	volatile unsigned short *regs = base;

+

+	regs[reg] = val;

+	regs[reg + 2] = val >> 16;

+}

+

+static unsigned long reg_r(void *base, int reg)

+{

+	volatile unsigned short *regs = base;

+	unsigned long val;

+

+	val = regs[reg];

+	val |= regs[reg + 2] << 16;

+	return val;

+}

+

+static unsigned long mac_r(void *base, int reg)

+{

+	reg_w(base, 0xA4, 0xc0000000 + reg);

+	return reg_r(base, 0xA8);

+}

+

+static void dump_eep(void *base)

+{

+	int i;

+

+	printf("Current eeprom:\n");

+	for (i = 0; i < 32; i++) {

+		while (reg_r(base, E2P_CMD) & E2P_CMD_EPC_BUSY_)

+			;

+		reg_w(base, E2P_CMD, 0

+		      | E2P_CMD_EPC_CMD_READ_

+		      | i);

+		reg_w(base, E2P_CMD, 0

+		      | E2P_CMD_EPC_BUSY_

+		      | E2P_CMD_EPC_CMD_READ_

+		      | i);

+		while (reg_r(base, E2P_CMD) & E2P_CMD_EPC_BUSY_)

+			;

+		printf("%02lx", reg_r(base, E2P_DATA));

+		putchar((i & 7) == 7 ? '\n' : ' ');

+	}

+}

+

+int verbose = 0;

+int main(int argc, char **argv)

+{

+	int fd, i;

+	void *base;

+	unsigned char macaddr[8];

+	unsigned long macregs[2];

+

+	if (getenv("VERBOSE")) verbose = 1;

+

+	/* First, access current information */

+	if((fd = open("/dev/mem", O_RDWR | O_SYNC)) < 0) FATAL;

+	if (verbose) {

+		printf("/dev/mem opened.\n");

+		fflush(stdout);

+	}

+

+	base = mmap(0, MAP_SIZE, PROT_READ | PROT_WRITE, MAP_SHARED, fd,

+			MAP_BASE);

+

+	if(base == (void *) -1) FATAL;

+	if (verbose) {

+		printf("Memory mapped at address %p.\n", base);

+		fflush(stdout);

+	}

+	macregs[0] = mac_r(base, 2);

+	macregs[1] = mac_r(base, 3);

+	printf("Current mac registers: %08lx %08lx\n",

+	       macregs[0], macregs[1]);

+	memcpy(macaddr+0, macregs+1, 4);

+	memcpy(macaddr+4, macregs+0, 4);

+	printf("Current mac address %02x:%02x:%02x:%02x:%02x:%02x\n",

+	       macaddr[0], macaddr[1], macaddr[2], macaddr[3], macaddr[4],

+	       macaddr[5]);

+	printf("Current status in E2P_CMD: %08lx\n", reg_r(base, 0xB0));

+	/* Then, parse information */

+	if(argc != 2) {

+		fprintf(stderr, "\n%s: Use: \"%s <mac>\" or \"%s -r\"\n",

+			argv[0], argv[0], argv[0]);

+		exit(1);

+	}

+	if (!strcmp(argv[1], "-r")) {

+		int fd;

+		fd = open("/dev/urandom", O_RDONLY);

+		if (fd < 0) FATAL;

+		if (read(fd, macaddr, 6) != 6) FATAL;

+		close(fd);

+		macaddr[0] &= 0xfe;	/* clear multicast bit */

+		macaddr[0] |= 0x02;	/* set local assignment bit (IEEE802) */

+	} else {

+		i = sscanf(argv[1], "%hhx:%hhx:%hhx:%hhx:%hhx:%hhx:%hhx",

+			   macaddr+0, macaddr+1, macaddr+2, macaddr+3,

+			   macaddr+4, macaddr+5, macaddr+6);

+		if (i != 6) FATAL;

+	}

+	printf("Writing mac address %02x:%02x:%02x:%02x:%02x:%02x\n",

+	       macaddr[0], macaddr[1], macaddr[2], macaddr[3], macaddr[4],

+	       macaddr[5]);

+

+	/*

+	 * Finally, access eeprom -- note that GPIO_CFG must be fixed.

+	 */

+

+	printf("gpiocfg was %08lx\n", reg_r(base, GPIO_CFG));

+	reg_w(base, GPIO_CFG, 0); /* to be able to access EEPROM */

+	printf("gpiocfg  is %08lx\n", reg_r(base, GPIO_CFG));

+

+	/* Dump, change, re-dump */

+	dump_eep(base);

+

+	while (reg_r(base, E2P_CMD) & E2P_CMD_EPC_BUSY_)

+		;

+	reg_w(base, E2P_CMD, 0

+	      | E2P_CMD_EPC_CMD_EWEN_ /* enable write */

+		);

+	reg_w(base, E2P_CMD, 0

+	      | E2P_CMD_EPC_BUSY_

+	      | E2P_CMD_EPC_CMD_EWEN_ /* enable write */

+		);

+	while (reg_r(base, E2P_CMD) & E2P_CMD_EPC_BUSY_)

+		;

+	/* The previous one would timeout if eeprom is missing */

+	if (reg_r(base, E2P_CMD) & E2P_CMD_EPC_TIMEOUT_)

+		FATAL;

+

+	printf("Write...\n");

+	for (i = 0; i < 7; i++) { /* 0xa5 magic byte and 6 mac bytes */

+		int datum;

+

+		if (i == 0) datum = 0xa5;

+		else datum = macaddr[i-1];

+

+		while (reg_r(base, E2P_CMD) & E2P_CMD_EPC_BUSY_)

+			;

+		reg_w(base, E2P_DATA, datum);

+		reg_w(base, E2P_CMD, 0

+		      | E2P_CMD_EPC_CMD_WRITE_

+		      | i);

+		reg_w(base, E2P_CMD, 0

+		      | E2P_CMD_EPC_BUSY_

+		      | E2P_CMD_EPC_CMD_WRITE_

+		      | i);

+		while (reg_r(base, E2P_CMD) & E2P_CMD_EPC_BUSY_)

+			;

+	}

+

+	reg_w(base, E2P_CMD, 0

+	      | E2P_CMD_EPC_CMD_EWDS_ /* disable write */

+		);

+

+

+	dump_eep(base);

+

+	exit(0);

+}