Terrible, Horrible, No Good, Very Bad Hack

This was less effort than writing a proper driver for the card in
question.

Long story short:
- GS/WH hugepage "sysmem" DMA don't act right under SiFive Premier P550
  dev board
- Want to test a different piece of hardware with similar driver code
  path

Makefile

@@ -2,7 +2,7 @@
 # SPDX-License-Identifier: GPL-2.0-only
 
 obj-m += tenstorrent.o
-tenstorrent-y := module.o chardev.o enumerate.o interrupt.o grayskull.o wormhole.o pcie.o hwmon.o sg_helpers.o memory.o
+tenstorrent-y := module.o chardev.o enumerate.o interrupt.o grayskull.o wormhole.o pcie.o hwmon.o sg_helpers.o memory.o squirrel.o
 
 KDIR := /lib/modules/$(shell uname -r)/build
 KMAKE := $(MAKE) -C $(KDIR) M=$(CURDIR)

enumerate.h

@@ -15,6 +15,9 @@
 #define PCI_DEVICE_ID_GRAYSKULL	0xFACA
 #define PCI_DEVICE_ID_WORMHOLE	0x401E
 
+#define PCI_VENDOR_ID_XILINX 0x10ee
+#define PCI_DEVICE_ID_SQUIRREL 0x0666
+
 struct pci_dev;
 struct cdev;
 

module.c

@@ -94,12 +94,15 @@ MODULE_PARM_DESC(auto_reset_timeout, "Timeout duration in seconds for M3 auto re
 struct tenstorrent_device_class;
 extern struct tenstorrent_device_class grayskull_class;
 extern struct tenstorrent_device_class wormhole_class;
+extern struct tenstorrent_device_class squirrel_class;
 
 const struct pci_device_id tenstorrent_ids[] = {
 	{ PCI_DEVICE(PCI_VENDOR_ID_TENSTORRENT, PCI_DEVICE_ID_GRAYSKULL),
 	  .driver_data=(kernel_ulong_t)&grayskull_class },
 	{ PCI_DEVICE(PCI_VENDOR_ID_TENSTORRENT, PCI_DEVICE_ID_WORMHOLE),
 	  .driver_data=(kernel_ulong_t)&wormhole_class },
+	{ PCI_DEVICE(PCI_VENDOR_ID_XILINX, PCI_DEVICE_ID_SQUIRREL),
+	  .driver_data=(kernel_ulong_t)&squirrel_class },
 	{ 0 },
 };
 

squirrel.c

@@ -0,0 +1,44 @@
+// SPDX-FileCopyrightText: © 2023 Tenstorrent Inc.
+// SPDX-License-Identifier: GPL-2.0-only
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+#include <linux/types.h>
+
+#include "squirrel.h"
+#include "pcie.h"
+#include "module.h"
+#include "hwmon.h"
+
+
+static bool squirrel_init(struct tenstorrent_device *tt_dev) {
+	struct squirrel_device *wh_dev = tt_dev_to_sq_dev(tt_dev);
+
+	return true;
+}
+
+
+static bool squirrel_init_hardware(struct tenstorrent_device *tt_dev) {
+	return true;
+}
+
+static bool squirrel_post_hardware_init(struct tenstorrent_device *tt_dev) {
+	return true;
+}
+
+static void squirrel_cleanup_hardware(struct tenstorrent_device *tt_dev) {
+}
+
+static void squirrel_cleanup(struct tenstorrent_device *tt_dev) {
+	struct squirrel_device *sq_dev = tt_dev_to_sq_dev(tt_dev);
+}
+
+struct tenstorrent_device_class squirrel_class = {
+	.name = "Squirrel",
+	.instance_size = sizeof(struct squirrel_device),
+	.init_device = squirrel_init,
+	.init_hardware = squirrel_init_hardware,
+	.post_hardware_init = squirrel_post_hardware_init,
+	.cleanup_hardware = squirrel_cleanup_hardware,
+	.cleanup_device = squirrel_cleanup,
+	.reboot = squirrel_cleanup_hardware,
+};

squirrel.h

@@ -0,0 +1,17 @@
+// SPDX-FileCopyrightText: © 2023 Tenstorrent Inc.
+// SPDX-License-Identifier: GPL-2.0-only
+
+#ifndef TTDRIVER_WORMHOLE_H_INCLUDED
+#define TTDRIVER_WORMHOLE_H_INCLUDED
+
+#include <linux/types.h>
+#include "device.h"
+
+struct squirrel_device {
+	struct tenstorrent_device tt;
+};
+
+#define tt_dev_to_sq_dev(ttdev) \
+	container_of((tt_dev), struct squirrel_device, tt)
+
+#endif