[Skiboot] [PATCH v3 3/9] Device-Tree(DT) entry for per-chip HOMER offset

[Madhavan Srinivasan]

OPAL sends two set of information to kernel.
1) Information about the per-chip PORE_SLW_IMA HOMER offset to kernel,
2) Information about each support Nest units and their events.

Device tree Information Layout for Nest Instrumentation:

/-
 |
 -ima-chip@<chip-id>
  |
  - Homer base + SLW Offset
  - Size
  - ...
 -<Nest Units>
  |
  - <events>
  - unit.<events>.unit
  - scale.<events>.scale
  - ...

In this patch, code added to pass per-chip PORE_SLW_IMA HOMER offset to kernel
as part of device tree entry under "ima-chip@<chip-id>" directory

Signed-off-by: Madhavan Srinivasan <maddy at linux.vnet.ibm.com>
---
 hw/nest.c | 46 ++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 46 insertions(+)

diff --git a/hw/nest.c b/hw/nest.c
index 9115e5c7fa26..3bc16aed49b5 100644
--- a/hw/nest.c
+++ b/hw/nest.c
@@ -109,10 +109,56 @@ int load_catalogue_lid(int loaded)
 
 void nest_pmu_init(int loaded)
 {
+	struct proc_chip *chip;
+	struct dt_node *dev, *chip_dev;
+	u64 addr=0;
+
 	if (load_catalogue_lid(loaded)) {
 		printf("Nest_IMA: IMA Catalog lid failed to load\n");
 		return;
 	}
 
+	/*
+	 * Now that we have Chip level events enabled,
+	 * lets create DT entries. This is a top level directory under /
+	 * for nest pmu units.
+	 */
+	dev = dt_new(dt_root, "nest-ima");
+	if (!dev) {
+		prlog(PR_DEBUG,"Nest_IMA: nest-ima dev creation failed \n");
+		return;
+	}
+
+	/*
+	 * Start exposing per-chip SLW_IMA FW offset in HOMER Region.
+	 */
+	for_each_chip(chip) {
+		chip_dev = dt_new_addr(dev, "ima-chip", chip->id);
+		if (!chip_dev) {
+			prlog(PR_DEBUG,"Nest_IMA: ima-chip dev creation failed \n");
+			return;
+		}
+
+		/*
+		 * Design:
+		 *  PORE_SLW_IMA FW will program Nest counters with
+		 *  pre-defined set of events (provided in catalog) and dump
+		 *  counter data in a fixed HOMER offset.
+		 *
+		 *  HOMER Region layout has reserved memory for
+		 *  PORE_SLW_IMA FW starting from 0x320000 to 0x39FFFF
+		 *
+		 *  PORE_SLW_IMA uses this region to dump different Nest unit
+		 *  counter data. This address is passed to kernel as base
+		 *  address to map. Individual counter offsets are passed
+		 *  in the event file.
+		 */
+		dt_add_property_cells(chip_dev, "ibm,chip-id", chip->id);
+		addr = chip->homer_base + SLW_IMA_OFFSET;
+		dt_add_property_u64(chip_dev, "reg", addr);
+		dt_add_property_cells(chip_dev, "size", SLW_IMA_SIZE);
+		dt_add_property(chip_dev, "ibm,ima-chip", NULL, 0);
+	}
+
 	return;
 }
-- 
1.9.1