Target Access (Pci Bus → G-Bus Address Conversion) - Toshiba TMPR4925 Manual

Table 10.3.3 Initiator Access Space Properties Register
Memory Space 0
Memory Space 1
Memory Space 2
I/O Space
BusMasterEnable:
Host mode:
Satellite mode: Command Register Bus Master bit
Target Access (PCI Bus → G-Bus Address Conversion)
10.3.5
During PCI target access, the PCI Bus address of the Bus transaction issued by the PCI Bus is
converted into a G-Bus address and is used to issue a Bus transaction on the G-Bus. 32-bit PCI Bus
addresses are used on the PCI Bus. Also, 32-bit physical addresses are used on the G-Bus.
Three memory access windows and one I/O access window can be set in the PCI bus space (Figure
10.3.5). The size of each memory window is variable from 1 MByte to 512 MBytes. The size of the I/O
windo is variable from 256 Bytes to 64 Kbytes. When Bus transactions to these access windows is
issued on the PCI Bus, these Bus transactions are accepted as PCI target devices. The PCI Bus Address
is converted into G-Bus addresses, then Bus transactions are issued to the G-Bus.
The memory space window responds to the PCI memory space access command. The I/O space
window responds to the PCI I/O space access command.
0xFFFF_FFFF
0x00_0000_0000
PCI I/O Space
Enable
BusMasterEnable & G2PCFG.G2PM0EN
BusMasterEnable & G2PCFG.G2PM1EN
BusMasterEnable & G2PCFG.G2PM2EN
BusMasterEnable & G2PCFG.G2PIOEN
PCI State Command Register Bus Master Bit (PCISTATUS.BM)
0xFFFF_FFFF
0x0000_0000
Memory Access Window
I/O Access Window
Figure 10.3.5 Target Access Memory Window
10-10
Chapter 10 PCI Controller
Word Swap
G2PCFG.BSWAPM0
G2PCFG.BSWAPM1
G2PCFG.BSWAPM2
G2PCFG.BSWAPIO
0xFFFF_FFFF
0x00_0000_0000
G-Bus Space PCI Memory Space