1 files changed, 167 insertions, 0 deletions
diff --git a/roms/skiboot/hw/ocmb.c b/roms/skiboot/hw/ocmb.c
new file mode 100644
index 000000000..bc470d0ab
--- /dev/null
+++ b/roms/skiboot/hw/ocmb.c
@@ -0,0 +1,167 @@
+// SPDX-License-Identifier: Apache-2.0 OR GPL-2.0-or-later
+/*
+ * Open Capi Memory Buffer chip
+ *
+ * Copyright 2020 IBM Corp.
+ */
+
+
+#define pr_fmt(fmt)	"OCMB: " fmt
+
+#include <skiboot.h>
+#include <xscom.h>
+#include <device.h>
+#include <ocmb.h>
+#include <io.h>
+#include <inttypes.h>
+
+struct ocmb_range {
+	uint64_t start;
+	uint64_t end;
+	uint64_t flags;
+
+	/* flags come from hdat */
+#define ACCESS_8B PPC_BIT(0)
+#define ACCESS_4B PPC_BIT(1)
+#define ACCESS_SIZE_MASK (ACCESS_8B | ACCESS_4B)
+};
+
+struct ocmb {
+	struct scom_controller scom;
+	int range_count;
+	struct ocmb_range ranges[];
+};
+
+static const struct ocmb_range *find_range(const struct ocmb *o, uint64_t offset)
+{
+	int i;
+	uint64_t addr = offset & ~(HRMOR_BIT);
+
+	for (i = 0; i < o->range_count; i++) {
+		uint64_t start = o->ranges[i].start;
+		uint64_t end = o->ranges[i].end;
+
+		if (addr >= start && addr <= end)
+			return &o->ranges[i];
+	}
+
+	return NULL;
+}
+
+static int64_t ocmb_fake_scom_write(struct scom_controller *f,
+				    uint32_t __unused chip_id,
+				    uint64_t offset, uint64_t val)
+{
+	const struct ocmb *o = f->private;
+	const struct ocmb_range *r;
+
+	r = find_range(o, offset);
+	if (!r) {
+		prerror("no matching address range!\n");
+		return OPAL_XSCOM_ADDR_ERROR;
+	}
+
+	switch (r->flags & ACCESS_SIZE_MASK) {
+	case ACCESS_8B:
+		if (offset & 0x7)
+			return OPAL_XSCOM_ADDR_ERROR;
+		out_be64((void *) offset, val);
+		break;
+
+	case ACCESS_4B:
+		if (offset & 0x3)
+			return OPAL_XSCOM_ADDR_ERROR;
+		out_be32((void *) offset, val);
+		break;
+	default:
+		prerror("bad flags? %llx\n", r->flags);
+		return OPAL_XSCOM_ADDR_ERROR;
+	}
+
+	return OPAL_SUCCESS;
+}
+
+static int64_t ocmb_fake_scom_read(struct scom_controller *f,
+				   uint32_t chip_id __unused,
+				   uint64_t offset, uint64_t *val)
+{
+	const struct ocmb *o = f->private;
+	const struct ocmb_range *r = NULL;
+
+	r = find_range(o, offset);
+	if (!r) {
+		prerror("no matching address range!\n");
+		return OPAL_XSCOM_ADDR_ERROR;
+	}
+
+
+	switch (r->flags & ACCESS_SIZE_MASK) {
+	case ACCESS_8B:
+		if (offset & 0x7)
+			return OPAL_XSCOM_ADDR_ERROR;
+		*val = in_be64((void *) offset);
+		break;
+
+	case ACCESS_4B:
+		if (offset & 0x3)
+			return OPAL_XSCOM_ADDR_ERROR;
+		*val = in_be32((void *) offset);
+		break;
+	default:
+		prerror("bad flags? %llx\n", r->flags);
+		return OPAL_XSCOM_ADDR_ERROR;
+	}
+
+	return OPAL_SUCCESS;
+}
+
+static bool ocmb_probe_one(struct dt_node *ocmb_node)
+{
+	uint64_t chip_id = dt_prop_get_u32(ocmb_node, "ibm,chip-id");
+	const struct dt_property *flags;
+	int i = 0, num = 0;
+	struct ocmb *ocmb;
+
+	num = dt_count_addresses(ocmb_node);
+
+	ocmb = zalloc(sizeof(*ocmb) + sizeof(*ocmb->ranges) * num);
+	if (!ocmb)
+		return false;
+
+	ocmb->scom.private = ocmb;
+	ocmb->scom.part_id = chip_id;
+	ocmb->scom.write = ocmb_fake_scom_write;
+	ocmb->scom.read = ocmb_fake_scom_read;
+	ocmb->range_count = num;
+
+	flags = dt_require_property(ocmb_node, "flags", sizeof(u64) * num);
+
+	for (i = 0; i < num; i++) {
+		uint64_t start, size;
+
+		start = dt_get_address(ocmb_node, i, &size);
+
+		ocmb->ranges[i].start = start;
+		ocmb->ranges[i].end = start + size - 1;
+		ocmb->ranges[i].flags = dt_property_get_u64(flags, i);
+
+		prlog(PR_DEBUG, "Added range:  %" PRIx64 " - [%llx - %llx]\n",
+			chip_id, start, start + size - 1);
+	}
+
+	if (scom_register(&ocmb->scom))
+		prerror("Error registering fake scom\n");
+
+	dt_add_property(ocmb_node, "scom-controller", NULL, 0);
+	prlog(PR_NOTICE, "Added scom controller for %s\n", ocmb_node->name);
+
+	return true;
+}
+
+void ocmb_init(void)
+{
+	struct dt_node *dn;
+
+	dt_for_each_compatible(dt_root, dn, "ibm,explorer")
+		ocmb_probe_one(dn);
+}