soc/intel/common/block/p2sb: Add ioapic BDF functions

This allows to get/set the IOAPIC bus device function.

Change-Id: Ib5bb409efbcbc5729cf0e996655c7ac3f6a78223
Signed-off-by: Arthur Heymans <arthur@aheymans.xyz>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/47534
Reviewed-by: Angel Pons <th3fanbus@gmail.com>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>

src/soc/intel/common/block/include/intelblocks/p2sb.h

@@ -40,6 +40,9 @@ union p2sb_bdf {
 
 union p2sb_bdf p2sb_get_hpet_bdf(void);
 void p2sb_set_hpet_bdf(union p2sb_bdf bdf);
+union p2sb_bdf p2sb_get_ioapic_bdf(void);
+void p2sb_set_ioapic_bdf(union p2sb_bdf bdf);
+
 
 /* SOC overrides */
 /*

src/soc/intel/common/block/p2sb/p2sb.c

@@ -73,6 +73,25 @@ void p2sb_set_hpet_bdf(union p2sb_bdf bdf)
 	pci_write_config16(PCH_DEV_P2SB, PCH_P2SB_HBDF, bdf.raw);
 }
 
+union p2sb_bdf p2sb_get_ioapic_bdf(void)
+{
+	const bool was_hidden = p2sb_is_hidden();
+	if (was_hidden)
+		p2sb_unhide();
+
+	union p2sb_bdf bdf = { .raw = pci_read_config16(PCH_DEV_P2SB, PCH_P2SB_IBDF) };
+
+	if (was_hidden)
+		p2sb_hide();
+
+	return bdf;
+}
+
+void p2sb_set_ioapic_bdf(union p2sb_bdf bdf)
+{
+	pci_write_config16(PCH_DEV_P2SB, PCH_P2SB_IBDF, bdf.raw);
+}
+
 static void p2sb_set_hide_bit(int hide)
 {
 	const uint16_t reg = PCH_P2SB_E0 + 1;