Add Swift platform

Swift is a dual-chip Axone system, wired for four possible GPUs. This is
akin to a POWER9P version of a (Redbud) Witherspoon.

Add a platform definition for this system, using details from v1.1 of
the design workbook (29 May 2019).

Signed-off-by: Reza Arbab <arbab@linux.ibm.com>
Signed-off-by: Oliver O'Halloran <oohall@gmail.com>

platforms/astbmc/Makefile.inc

@@ -6,7 +6,7 @@ ASTBMC_OBJS = pnor.o common.o slots.o \
 	      garrison.o barreleye.o \
 	      witherspoon.o zaius.o romulus.o p9dsu.o \
 	      vesnin.o nicole.o mihawk.o\
-	      talos.o
+	      talos.o swift.o
 
 ASTBMC = $(PLATDIR)/astbmc/built-in.a
 $(ASTBMC): $(ASTBMC_OBJS:%=$(PLATDIR)/astbmc/%)

platforms/astbmc/swift.c

@@ -0,0 +1,141 @@
+/* Copyright 2019 IBM Corp.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *	http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
+ * implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include <skiboot.h>
+#include <ipmi.h>
+#include <npu3.h>
+#include "astbmc.h"
+
+/* nvidia,link-speed uses a magic driver value */
+#define NVIDIA_LINK_SPEED_20000000000_BPS 3
+#define NVIDIA_LINK_SPEED_25781250000_BPS 8
+#define NVIDIA_LINK_SPEED_25000000000_BPS 9
+
+static void swift_npu3_device_detect(struct npu3 *npu)
+{
+	struct npu3_dev *dev;
+	uint32_t node, gpu_index;
+	char slot[6];
+
+	node = P9_GCID2NODEID(npu->chip_id);
+
+	switch (npu->index) {
+	case 0:
+		gpu_index = node * 2 + 1;
+		break;
+	case 2:
+		gpu_index = node * 2;
+		break;
+	default:
+		return;
+	}
+
+	snprintf(slot, sizeof(slot), "GPU%d", gpu_index);
+
+	npu3_for_each_dev(dev, npu) {
+		dev->type = NPU3_DEV_TYPE_NVLINK;
+		dt_add_property_string(dev->dn, "ibm,slot-label", slot);
+		dt_add_property_u64(dev->dn, "ibm,link-speed", 25000000000ull);
+		dt_add_property_cells(dev->dn, "nvidia,link-speed",
+				      NVIDIA_LINK_SPEED_25000000000_BPS);
+	}
+}
+
+#define SWIFT_POSSIBLE_GPUS 4
+
+#define G(g)	(devs[g] ? devs[g]->nvlink.gpu->dn->phandle : 0)
+#define N(g)	(devs[g] ? devs[g]->npu->nvlink.phb.dt_node->phandle : 0)
+
+#define add_peers_prop(g, p...)					\
+	if (devs[g])  						\
+		dt_add_property_cells(devs[g]->nvlink.gpu->dn,	\
+				      "ibm,nvlink-peers", ##p)
+
+static void swift_finalise_dt(bool is_reboot)
+{
+	struct npu3 *npu;
+	struct npu3_dev *dev;
+	struct npu3_dev *devs[SWIFT_POSSIBLE_GPUS] = {};
+	int32_t index;
+
+	if (is_reboot)
+		return;
+
+	if (npu3_chip_possible_gpus() != 2) {
+		prlog(PR_ERR, "NPU: Unknown link topology detected\n");
+		return;
+	}
+
+	/* Collect the first link we find for each GPU */
+	npu3_for_each_nvlink_npu(npu) {
+		npu3_for_each_nvlink_dev(dev, npu) {
+			index = npu3_dev_gpu_index(dev);
+			if (index == -1 || index >= ARRAY_SIZE(devs))
+				continue;
+
+			if (dev->nvlink.gpu && !devs[index])
+				devs[index] = dev;
+		}
+	}
+
+	/* Add GPU interconnect properties */
+	add_peers_prop(0, G(3), G(2), G(2), G(2),
+			  G(3), G(1), G(1), G(1),
+			  N(0), N(0), N(0), N(0));
+
+	add_peers_prop(1, G(2), G(3), G(3), G(3),
+			  G(0), G(0), G(0), G(2),
+			  N(1), N(1), N(1), N(1));
+
+	add_peers_prop(2, G(1), G(3), G(3), G(3),
+			  G(0), G(0), G(0), G(1),
+			  N(2), N(2), N(2), N(2));
+
+	add_peers_prop(3, G(2), G(2), G(2), G(0),
+			  G(1), G(1), G(0), G(1),
+			  N(3), N(3), N(3), N(3));
+}
+
+static bool swift_probe(void)
+{
+	if (!dt_node_is_compatible(dt_root, "ibm,swift"))
+		return false;
+
+	/* Lot of common early inits here */
+	astbmc_early_init();
+
+	/* Setup UART for use by OPAL (Linux hvc) */
+	uart_set_console_policy(UART_CONSOLE_OPAL);
+
+	return true;
+}
+
+DECLARE_PLATFORM(swift) = {
+	.bmc			= &bmc_plat_ast2500_openbmc,
+	.cec_power_down		= astbmc_ipmi_power_down,
+	.cec_reboot		= astbmc_ipmi_reboot,
+	.elog_commit		= ipmi_elog_commit,
+	.exit			= astbmc_exit,
+	.finalise_dt		= swift_finalise_dt,
+	.init			= astbmc_init,
+	.name			= "Swift",
+	.npu3_device_detect	= swift_npu3_device_detect,
+	.pci_get_slot_info	= dt_slot_get_slot_info,
+	.probe			= swift_probe,
+	.resource_loaded	= flash_resource_loaded,
+	.start_preload_resource	= flash_start_preload_resource,
+	.terminate		= ipmi_terminate,
+};