diff options
Diffstat (limited to 'drivers/media/common/ttpci-eeprom.c')
| -rw-r--r-- | drivers/media/common/ttpci-eeprom.c | 159 |
1 files changed, 159 insertions, 0 deletions
diff --git a/drivers/media/common/ttpci-eeprom.c b/drivers/media/common/ttpci-eeprom.c new file mode 100644 index 000000000000..ef8746684d31 --- /dev/null +++ b/drivers/media/common/ttpci-eeprom.c @@ -0,0 +1,159 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + Retrieve encoded MAC address from 24C16 serial 2-wire EEPROM, + decode it and store it in the associated adapter struct for + use by dvb_net.c + + This card appear to have the 24C16 write protect held to ground, + thus permitting normal read/write operation. Theoretically it + would be possible to write routines to burn a different (encoded) + MAC address into the EEPROM. + + Robert Schlabbach GMX + Michael Glaum KVH Industries + Holger Waechtler Convergence + + Copyright (C) 2002-2003 Ralph Metzler <rjkm@metzlerbros.de> + Metzler Brothers Systementwicklung GbR + + +*/ + +#include <asm/errno.h> +#include <linux/init.h> +#include <linux/module.h> +#include <linux/string.h> +#include <linux/i2c.h> +#include <linux/etherdevice.h> + +#include "ttpci-eeprom.h" + +#if 1 +#define dprintk(x...) do { printk(x); } while (0) +#else +#define dprintk(x...) do { } while (0) +#endif + + +static int check_mac_tt(u8 *buf) +{ + int i; + u16 tmp = 0xffff; + + for (i = 0; i < 8; i++) { + tmp = (tmp << 8) | ((tmp >> 8) ^ buf[i]); + tmp ^= (tmp >> 4) & 0x0f; + tmp ^= (tmp << 12) ^ ((tmp & 0xff) << 5); + } + tmp ^= 0xffff; + return (((tmp >> 8) ^ buf[8]) | ((tmp & 0xff) ^ buf[9])); +} + +static int getmac_tt(u8 * decodedMAC, u8 * encodedMAC) +{ + u8 xor[20] = { 0x72, 0x23, 0x68, 0x19, 0x5c, 0xa8, 0x71, 0x2c, + 0x54, 0xd3, 0x7b, 0xf1, 0x9E, 0x23, 0x16, 0xf6, + 0x1d, 0x36, 0x64, 0x78}; + u8 data[20]; + int i; + + /* In case there is a sig check failure have the orig contents available */ + memcpy(data, encodedMAC, 20); + + for (i = 0; i < 20; i++) + data[i] ^= xor[i]; + for (i = 0; i < 10; i++) + data[i] = ((data[2 * i + 1] << 8) | data[2 * i]) + >> ((data[2 * i + 1] >> 6) & 3); + + if (check_mac_tt(data)) + return -ENODEV; + + decodedMAC[0] = data[2]; decodedMAC[1] = data[1]; decodedMAC[2] = data[0]; + decodedMAC[3] = data[6]; decodedMAC[4] = data[5]; decodedMAC[5] = data[4]; + return 0; +} + +int ttpci_eeprom_decode_mac(u8 *decodedMAC, u8 *encodedMAC) +{ + u8 xor[20] = { 0x72, 0x23, 0x68, 0x19, 0x5c, 0xa8, 0x71, 0x2c, + 0x54, 0xd3, 0x7b, 0xf1, 0x9E, 0x23, 0x16, 0xf6, + 0x1d, 0x36, 0x64, 0x78}; + u8 data[20]; + int i; + + memcpy(data, encodedMAC, 20); + + for (i = 0; i < 20; i++) + data[i] ^= xor[i]; + for (i = 0; i < 10; i++) + data[i] = ((data[2 * i + 1] << 8) | data[2 * i]) + >> ((data[2 * i + 1] >> 6) & 3); + + if (check_mac_tt(data)) + return -ENODEV; + + decodedMAC[0] = data[2]; + decodedMAC[1] = data[1]; + decodedMAC[2] = data[0]; + decodedMAC[3] = data[6]; + decodedMAC[4] = data[5]; + decodedMAC[5] = data[4]; + return 0; +} +EXPORT_SYMBOL(ttpci_eeprom_decode_mac); + +static int ttpci_eeprom_read_encodedMAC(struct i2c_adapter *adapter, u8 * encodedMAC) +{ + int ret; + u8 b0[] = { 0xcc }; + + struct i2c_msg msg[] = { + { .addr = 0x50, .flags = 0, .buf = b0, .len = 1 }, + { .addr = 0x50, .flags = I2C_M_RD, .buf = encodedMAC, .len = 20 } + }; + + /* dprintk("%s\n", __func__); */ + + ret = i2c_transfer(adapter, msg, 2); + + if (ret != 2) /* Assume EEPROM isn't there */ + return (-ENODEV); + + return 0; +} + + +int ttpci_eeprom_parse_mac(struct i2c_adapter *adapter, u8 *proposed_mac) +{ + int ret; + u8 encodedMAC[20]; + u8 decodedMAC[6]; + + ret = ttpci_eeprom_read_encodedMAC(adapter, encodedMAC); + + if (ret != 0) { /* Will only be -ENODEV */ + dprintk("Couldn't read from EEPROM: not there?\n"); + eth_zero_addr(proposed_mac); + return ret; + } + + ret = getmac_tt(decodedMAC, encodedMAC); + if( ret != 0 ) { + dprintk("adapter failed MAC signature check\n"); + dprintk("encoded MAC from EEPROM was %*phC", + (int)sizeof(encodedMAC), &encodedMAC); + eth_zero_addr(proposed_mac); + return ret; + } + + memcpy(proposed_mac, decodedMAC, 6); + dprintk("adapter has MAC addr = %pM\n", decodedMAC); + return 0; +} + +EXPORT_SYMBOL(ttpci_eeprom_parse_mac); + +MODULE_LICENSE("GPL"); +MODULE_AUTHOR("Ralph Metzler, Marcus Metzler, others"); +MODULE_DESCRIPTION("Decode dvb_net MAC address from EEPROM of PCI DVB cards made by Siemens, Technotrend, Hauppauge"); |