The PCIe Miscellaneous tab options for the AXI Bridge mode (Functional Mode option) are shown in the following figure.
Figure 1. PCIe Miscellaneous Tab for AXI Bridge Functional Mode
The options are defined as follows:
- Bar Indicator
- This is the space allocated for Interrupt processing registers that are shared between AXI Bridge and AXI DMA. This register space includes an MSI-X table, and when MSI-X Internal is selected, 64KB address space from the BAR indicated here will be reserved for the MSI-X table. Depending on PCIe BAR selection this register space can be allocated to any selected BAR space (BAR0 to BAR5). This options is valid only when MSI-X Internal option is selected. For all other interrupt options there is no allocated space.
- User Interrupts
- Select number of user interrupts.
- Legacy Interrupt Settings
- Select one of the Legacy Interrupts: INTA, INTB, INTC, or INTD.
- Number of User Interrupt Request
- Up to 16 user interrupt requests can be selected.
- MSI Capabilities
- By default, MSI Capabilities is enabled, and 1 vector is enabled. You can choose up to 16 vectors. In general, Linux uses only 1 vector for MSI. This option can be disabled.
- MSI-X Capabilities
- Select a MSI-X event. For more information, see MSI-X Vector Table and PBA (0x8).
- MSI-X Implementation Location
- For MSI-X, there are two options: Internal and External. When Internal is selected, MSI-X table is internal to the IP and the table can be accessed depending on BAR Indicator selection. When External is selected, MSI-X related ports are brought out of IP and user is responsible to make table outside of IP. In this case, Bar Indicator is not used.
- Completion Timeout Configuration
- By default, completion timeout is set to 50 ms. Option of 50 us is also available. This option is deprecated and does not have any effect. This option is now maintained from the Device Control 2 register in the PCIe Configuration Space register.
- Config Extended Interface
- PCIe extended interface can be selected for more configuration space. When Configuration Extend Interface is selected, you are responsible for adding logic to extend the interface to make it work properly.