Preliminary
www.ti.com
Use Case
13.3 Use Case
13.3.1 PCIe Root Complex
When the PCIESS is desired to operate as a Root Complex (RC), the following initialization sequence
is recommended.
13.3.1.1 Initialization Sequence
The initialization sequence is:
1. Configure PCIe Mode of operation to RC Mode by programming PCIE_CFG.PCIE_DEVTYPE with a
value of 2h.
2. Bring PCIESS out of reset through the device level reset controller.
3. Enable and configure PCIe Clock (See PCIE_CFG Register Description). Note: The Default PLL
Multiplier configuration value (PCIE_CFG.CFG_PLL = 1C9h) is most likely to be used if using a
100 MHz input clock source.
4. Wait for the PCIe PHY PLL to lock; wait for PCIe PLL Status (PCIE_CFG.PCIE_STSPLL) to change
to ‘1’.
5. Insure that the link is idle. Disable link training by de-asserting the LTSSM Enable bit in PCIESS
Control Register. Upon reset, the LTSSM Enable is de-asserted automatically by hardware,
CMD_STATUS.LTSSM_EN is zero.
6. Configure core registers through OCP Slave interface address space 0.
7. Initiate link training can be initiated by asserting LTSSM Enable bit in PCIESS Control Register;
programming CMD_STATUS.LTSSM_EN with a 1.
8. Insure link training completion and success by observing DEBUG0.LTSSM_STATE field change to
11h.
9. In conjunction with the system software, start bus enumeration and setup configuration space on
downstream ports.
10. Continue software handshake and initialization on the remote devices. This includes setting up
DMA protocols, interrupt procedures, etc.
11. With the completion of software initialization, DMA accesses can be started on various end points.
13.3.1.2 Configuration Accesses
Configuration accesses are made by RC port to individual function in each downstream EP device to
program the PCIe specific operating parameters. In particular, the configuration accesses are used to
allocate memory ranges for each downstream device, configure those memory ranges as IO or Memory
type, enable bus master capability on the device if necessary and also build a software database of
PCIE attributes and capabilities of each downstream device. Each downstream device can be
configured through the configuration access region of PCIESS. The PCIESS convert memory reads and
writes on the configuration region of OCP interface into configuration access on the serial link.
13.3.1.3 Memory Accesses
There are two types of memory accesses – the outbound memory accesses that are initiated by the
DMA on the PCIESS Slave port and the inbound memory accesses that are initiated by the PCIESS
Master port targeted to internal memory regions within the OCP Interconnect.
The outbound PCIe memory read and write accesses are made through the PCIESS slave port through
the device memory range that is dedicated to data transfers. The read and write transactions on this
region are directly mapped to PCI Express space by the PCIESS in conjunction with the outbound
address translation mechanism. The completions to the bus transactions are generated by PCIESS
when it receives completions from remote devices. In case of errors or timeouts, an error response is
provided. For reads, the error responses span as many phases as there would be data phases if the
error had not occurred.
1303
SPRUGX9 – 15 April 2011
Peripheral Component Interconnect Express (PCIe)
© 2011, Texas Instruments Incorporated
Содержание TMS320C6A816 Series
Страница 2: ...Preliminary 2 SPRUGX9 15 April 2011 Submit Documentation Feedback 2011 Texas Instruments Incorporated...
Страница 92: ...92 Read This First SPRUGX9 15 April 2011 Submit Documentation Feedback 2011 Texas Instruments Incorporated...
Страница 1122: ...1122 Multichannel Audio Serial Port McASP SPRUGX9 15 April 2011 Submit Documentation Feedback 2011 Texas Instruments Incorporated...
Страница 1562: ...1562 Real Time Clock RTC SPRUGX9 15 April 2011 Submit Documentation Feedback 2011 Texas Instruments Incorporated...
Страница 1658: ...1658 Timers SPRUGX9 15 April 2011 Submit Documentation Feedback 2011 Texas Instruments Incorporated...
Страница 1750: ...1750 UART IrDA CIR Module SPRUGX9 15 April 2011 Submit Documentation Feedback 2011 Texas Instruments Incorporated...
Страница 1984: ...1984 Universal Serial Bus USB SPRUGX9 15 April 2011 Submit Documentation Feedback 2011 Texas Instruments Incorporated...