phb4: Track PEC index in dt and phb4 struct

Knowing the PEC index is going to be important when we enable relaxed
ordering, so store this value for later use.

Signed-off-by: Alistair Popple <alistair@popple.id.au>
[arbab@linux.ibm.com: Rebase/refactor original changes]
Signed-off-by: Reza Arbab <arbab@linux.ibm.com>
Reviewed-By: Alistair Popple <alistair@popple.id.au>
Signed-off-by: Stewart Smith <stewart@linux.ibm.com>

doc/device-tree/pci.rst

@@ -37,6 +37,7 @@ The following is an example PCI host bridge and device from a POWER9 machine.
     phandle = <0x617>;
     ibm,phb-stack = <0xd8>;
     ibm,phb-index = <0x3>;
+    ibm,phb-pec-index = <0x2>; /* skiboot-v6.2 or later */
     reg = <0x600c3 0xc0300000 0x0 0x1000 0x600c3 0x60000000 0x0 0x10000000>;
     ibm,mmio-windows = <0x60200 0x0 0x40 0x0 0x600c1 0x80000000 0x0 0x80000000>;
     clock-frequency = <0x200 0x0>;

hw/phb4.c

@@ -5315,6 +5315,7 @@ static void phb4_create(struct dt_node *np)
 	/* Populate base stuff */
 	p->index = dt_prop_get_u32(np, "ibm,phb-index");
 	p->chip_id = chip_id;
+	p->pec = dt_prop_get_u32(np, "ibm,phb-pec-index");
 	chip = get_chip(p->chip_id);
 	p->regs = (void *)dt_get_address(np, 0, NULL);
 	p->int_mmio = (void *)dt_get_address(np, 1, NULL);
@@ -5623,6 +5624,7 @@ static void phb4_probe_stack(struct dt_node *stk_node, uint32_t pec_index,
 			      nest_base, nest_stack, pci_base, pci_stack, etu_base);
 	dt_add_property(np, "ibm,mmio-windows", mmio_win, 8 * mmio_win_sz);
 	dt_add_property_cells(np, "ibm,phb-index", phb_num);
+	dt_add_property_cells(np, "ibm,phb-pec-index", pec_index);
 	dt_add_property_cells(np, "ibm,phb-stack", stk_node->phandle);
 	dt_add_property_cells(np, "ibm,phb-stack-index", stk_index);
 	dt_add_property_cells(np, "ibm,chip-id", gcid);

include/phb4.h

@@ -169,6 +169,7 @@ struct phb4 {
 	unsigned int		index;	    /* 0..5 index inside p9 */
 	unsigned int		flags;
 	unsigned int		chip_id;    /* Chip ID (== GCID on p9) */
+	unsigned int		pec;
 	bool			broken;
 	unsigned int		rev;        /* 00MMmmmm */
 #define PHB4_REV_NIMBUS_DD10	0xa40001