CRITICALITY

Low

DESCRIPTION

The MSI bit in PCIECTRL_TI_CONF_IRQSTATUS_MSI register does not clear automatically even after all the vectors in PCIECTRL_PL_MSI_CTRL_INT_STATUS_N registers are cleared.

GUIDELINES

Software should manually clear PCIECTRL_TI_CONF_IRQSTATUS_MSI[4] MSI bit after making sure there are no vectors set in PCIECTRL_PL_MSI_CTRL_INT_STATUS_N registers. If MSI bit is cleared with some of the bits of PCIECTRL_PL_MSI_CTRL_INT_STATUS_N still set then those interrupts may be lost which may lead to non-functional remote endpoints.

Following is the recommended sequence for handling MSI interrupt to avoid missing any MSI interrupts:

1. Software reads PCIECTRL_TI_CONF_IRQSTATUS_MSI status register, and identifies an (unspecified) MSI event, as opposed to a PCI legacy event.
2. Software clears PCIECTRL_TI_CONF_IRQSTATUS_MSI[4] MSI.
3. Software reads PCIECTRL_PL_MSI_CTRL_INT_STATUS_N and identifies EP functions that raised MSI.
4. Software clears PCIECTRL_PL_MSI_CTRL_INT_STATUS_N status bit.
5. Software calls the EP function specific interrupt handlers for each of the vectors.
6. Repeat steps 3 to 5 until PCIECTRL_PL_MSI_CTRL_INT_STATUS_N reads 0.
7. Exit MSI IRQ handler, only if PCIECTRL_PL_MSI_CTRL_INT_STATUS_N is 0

REVISIONS IMPACTED

AM574x SR 1.0
AM576x SR 1.0

AM574x: 1.0

DRA75xP, DRA74xP, DRA77xP, DRA76xP: 1.0

TDA2Px: 1.0

AM576x: 1.0