SPRUI30H November 2015 – May 2024 DRA745 , DRA746 , DRA750 , DRA756
In the rest of this section, and for clarity:
Each PCIe controller has two hardware interrupt lines described in Table 24-501 and Table 24-503, which are level-sensitive. PCIe pulse interrupts are unsupported in the device.
The main HW interrupt line - PCIe_SS1_IRQ_INT0/PCIe_SS2_IRQ_INT0 receives all interrupt events related to the control of the PCIe operation, including power management and errors.
The MSI HW interrupt line - PCIe_SS1_IRQ_INT1/PCIe_SS2_IRQ_INT1 receives all interrupt events propagated by a remote EP over the PCIe interface, for specific (non-PCIe) applicative purposes, in conjunction with the PCIe transactions. This includes the legacy interrupts (INTx) as well as the Message Signaled Interrupts (MSI) proper, as defined by the PCIe standard.
MSI-X is unsupported by PCIe controller.
The difference between the two hardware interrupt types - "main" and "MSI" is that the main interrupt events are used by the PCIe interface, whereas the MSI interrupt uses the PCIe interface.
Incoming MSI events only exist in RC mode when MSI events are received over the PCIe wire. In EP mode, other mechanisms allow controller to generate (transmit) of the same type of interrupt events onto the PCIe bus.
The main interrupt events are further divided into PCI management and error events. The MSI interrupts are divided into legacy and MSI proper. Each of these four categories of events is described in Section 24.9.4.6.1 and Section 24.9.4.6.2.2.