On some platforms the I/O APIC interrupt pin#0-15 may be connected
to platform pci devices' interrupt pin. In such cases the legacy ISA
IRQ is not available so we should not write ISA interrupt entry if
it is already occupied.
Signed-off-by: Bin Meng <bmeng.cn@gmail.com>
Acked-by: Simon Glass <sjg@chromium.org>
Currently during writing MP table I/O interrupt assignment entry, we
assume the PIRQ is directly mapped to I/O APIC INTPIN#16-23, which
however is not always the case on some platforms.
Signed-off-by: Bin Meng <bmeng.cn@gmail.com>
Acked-by: Simon Glass <sjg@chromium.org>
Implement write_mp_table() to create a minimal working MP table.
This includes an MP floating table, a configuration table header
and all of the 5 base configuration table entries. The I/O interrupt
assignment table entry is created based on the same information used
in the creation of PIRQ routing table from device tree. A check
duplicated entry logic is applied to prevent writing multiple I/O
interrupt entries with the same information.
Use a Kconfig option GENERATE_MP_TABLE to tell U-Boot whether we
need actually write the MP table at the F seg, just like we did for
PIRQ routing and SFI tables. With MP table existence, linux kernel
will switch to I/O APIC and local APIC to process all the peripheral
interrupts instead of 8259 PICs. This takes full advantage of the
multicore hardware and the SMP kernel.
Signed-off-by: Bin Meng <bmeng.cn@gmail.com>
Acked-by: Simon Glass <sjg@chromium.org>
The MP table provides a way for the operating system to support
for symmetric multiprocessing as well as symmetric I/O interrupt
handling with the local APIC and I/O APIC. We provide a bunch of
APIs for U-Boot to write the floating table, configuration table
header as well as base and extended table entries.
Signed-off-by: Bin Meng <bmeng.cn@gmail.com>
Acked-by: Simon Glass <sjg@chromium.org>
Bin Meng