x86: Generate a valid MultiProcessor (MP) table

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>

1 files changed, 10 insertions, 0 deletions

diff --git a/arch/x86/include/asm/mpspec.h b/arch/x86/include/asm/mpspec.h
index 849113a940..efa9231f92 100644
--- a/arch/x86/include/asm/mpspec.h
+++ b/arch/x86/include/asm/mpspec.h
@@ -431,4 +431,14 @@ void mp_write_compat_address_space(struct mp_config_table *mc, int busid,
  */
 u32 mptable_finalize(struct mp_config_table *mc);
 
+/**
+ * write_mp_table() - Write MP table
+ *
+ * This writes MP table at a given address.
+ *
+ * @addr:	start address to write MP table
+ * @return:	end address of MP table
+ */
+u32 write_mp_table(u32 addr);
+
 #endif /* __ASM_MPSPEC_H */