[PATCH for-7.2 v4 07/11] ppc/pnv: add PHB4 helpers for user created pnv-phb

[Daniel Henrique Barboza <danielhb413@gmail.com>]

The PHB4 backend relies on a link with the corresponding PEC element.
This is trivial to do during machine_init() time for default devices,
but not so much for user created ones.

pnv_phb4_get_pec() is a small variation of the function that was
reverted by commit 9c10d86fee "ppc/pnv: Remove user-created PHB{3,4,5}
devices". We'll use it to determine the appropriate PEC for a given user
created pnv-phb that uses a PHB4 backend.

This is done during realize() time, in pnv_phb_user_device_init().

Signed-off-by: Daniel Henrique Barboza <danielhb413@gmail.com>
---
 hw/ppc/pnv.c | 35 ++++++++++++++++++++++++++++++++---
 1 file changed, 32 insertions(+), 3 deletions(-)

diff --git a/hw/ppc/pnv.c b/hw/ppc/pnv.c
index e82d6522f0..0644f45a1d 100644
--- a/hw/ppc/pnv.c
+++ b/hw/ppc/pnv.c
@@ -281,6 +281,34 @@ static void pnv_dt_icp(PnvChip *chip, void *fdt, uint32_t pir,
     g_free(reg);
 }
 
+static PnvPhb4PecState *pnv_phb4_get_pec(PnvChip *chip, PnvPHB4 *phb,
+                                         Error **errp)
+{
+    Pnv9Chip *chip9 = PNV9_CHIP(chip);
+    int chip_id = phb->chip_id;
+    int index = phb->phb_id;
+    int i, j;
+
+    for (i = 0; i < chip->num_pecs; i++) {
+        /*
+         * For each PEC, check the amount of phbs it supports
+         * and see if the given phb4 index matches an index.
+         */
+        PnvPhb4PecState *pec = &chip9->pecs[i];
+
+        for (j = 0; j < pec->num_phbs; j++) {
+            if (index == pnv_phb4_pec_get_phb_id(pec, j)) {
+                return pec;
+            }
+        }
+    }
+    error_setg(errp,
+               "pnv-phb4 chip-id %d index %d didn't match any existing PEC",
+               chip_id, index);
+
+    return NULL;
+}
+
 /*
  * Adds a PnvPHB to the chip. Returns the parent obj of the
  * PHB which varies with each version (phb version 3 is parented
@@ -302,10 +330,11 @@ Object *pnv_chip_add_phb(PnvChip *chip, PnvPHB *phb, Error **errp)
         chip8->num_phbs++;
 
         return OBJECT(chip);
-    } else {
-        /* phb4 support will be added later */
-        return NULL;
     }
+
+    phb->pec = pnv_phb4_get_pec(chip, PNV_PHB4(phb->backend), errp);
+
+    return OBJECT(phb->pec);
 }
 
 static void pnv_chip_power8_dt_populate(PnvChip *chip, void *fdt)
-- 
2.36.1