PMbus access

1st byte of rtn is length and last byte is for nothing if you want to read 9bytes data, you need to specify length 11 in i2c master write-read command, when length is set to 0, BMC will perform i2c write.

gcc object file linking

gcc -c xxx.c --> automatically generate xxx.o gcc yyy.c xxx.o --> automatically generate a.out You can use functions defined in xxx.c without including any header files in yyy.c

cpu smbus access

B:X|D:15|F:0 config 0x188 and then 0x184 0x188 -> 31:28 1010 specifies EEPROM’s. 0x188 -> 27 1’ = Clock signal is released high, allowing normal operation of CMD. 0x184 -> 23:16 Offset. 0x184 -> 31 SMB_CMD_TRIGGERCMD trigger 0x184 -> 29 SMB_WORD_ACCESS (0:byte, 1:word) 0x184 -> 28:27 SMB_WRT_PNTR (00:read. 01:write) 0x184 -> 26:24 SMB_SA. slave address

struct mapping

__attribute__((packed)); need to be added otherwise it may cause memory alignment issue #include #include #include #include #include #include #include #include #include #include #include struct test { uint8_t sig[4]; uint8_t len; uint8_t mic_sig[5]; uint32_t vid; uint16_t did; uint16_t idxx; } __attribute__((packed)); int main(){ uint8_t test_string[]={'K','I','D','O',0x40,'M','i','T','A','C',0x86,0x80,0x02,0x3c,0x86,0x81,0x01,0x3c}; struct test *info=(struct test *)test_string; printf("sig=%.4s len=0x%x mic_sig=%.5s vid=0x%04x did=0x%04x idxx=0x%04x\n" ,info->sig, info->len, info->mic_sig, info->vid, info->did, info->idxx); return 0; }

map pci configure space to memory

1: seek for RSDP (SIG: "RSD PTR ") --  main BIOS area below 1 MB
2: seek for RSDT (SIG: "RSDT")
3: determine table amount. -- (RSDT len -header)/ sizeof(table type: 32/64bits)
4: find MCFG table and check 0x24 - 0x28 <-- address="" configuration="" nbsp="" p="">
http://wiki.osdev.org/PCI_Express
http://wiki.osdev.org/RSDP
http://wiki.osdev.org/RSDT

After determining the MMIO base address and the total number of busses in the address space, you can read from the extended configuration address space. To access a specific register, you must use the following formula: Address = MMIO_BASE + { bus number[27:20], device number[19:15], function number[14:12], extended register number[11:8], register number[7:2], offset [1:0] }.

display scsi device type

sg_map -x

 -x     after  each  active  sg  device  name  is  displayed  there  are  five digits:
http://en.wikipedia.org/wiki/SCSI_Peripheral_Device_Type

cat /proc/scsi/scsi

DD-WRT PPTP client redirect gateway

administration --> commands --> commands text area --> save startup

sleep 90
OLDGW=$(nvram get wan_gateway)
VPNSRV=$(nvram get pptpd_client_srvip)
VPNSRVSUB=$(nvram get pptpd_client_srvsub)
PPTPDEV=$(route -n | grep ^${VPNSRVSUB%.[0-9]*} | awk '{print $NF}' | head -n 1)
VPNGW=$(ifconfig $PPTPDEV | grep -Eo "P-t-P:([0-9.]+)" | cut -d: -f2)
route add -host $VPNSRV gw $OLDGW
route del default gw $OLDGW
route add default gw $VPNGW

routing table
root@DD-WRT:~# route
Kernel IP routing table
Destination     Gateway         Genmask         Flags Metric Ref    Use Iface
default         192.168.240.1   0.0.0.0         UG    0      0        0 ppp0
127.0.0.0       *               255.0.0.0       U     0      0        0 lo
169.254.0.0     *               255.255.0.0     U     0      0        0 br0
192.168.0.0     *               255.255.0.0     U     0      0        0 vlan1
192.168.1.0     *               255.255.255.0   U     0      0        0 br0
192.168.240.0   *               255.255.255.0   U     0      0        0 ppp0
192.168.240.1   *               255.255.255.255 UH    0      0        0 ppp0
220.135.10.98   192.168.179.1   255.255.255.255 UGH   0      0        0 vlan1

enhanced script
#!/bin/sh
OLDGW=$(nvram get wan_gateway)
VPNSRV=$(nvram get pptpd_client_srvip)
VPNSRVSUB=$(nvram get pptpd_client_srvsub)
PPTPDEV=$(route -n | grep ^${VPNSRVSUB%.[0-9]*} | awk '{print $NF}' | head -n 1)
while [ ${#PPTPDEV} -eq 0 ]; do
  PPTPDEV=$(route -n | grep ^${VPNSRVSUB%.[0-9]*} | awk '{print $NF}' | head -n 1)
  echo "Retry"
  sleep 5
done
VPNGW=$(ifconfig $PPTPDEV | grep -Eo "P-t-P:([0-9.]+)" | cut -d: -f2)
route add -host $VPNSRV gw $OLDGW
route del default gw $OLDGW
route add default gw $VPNGW

ref: http://junan.name/1544.html