The Myriad ma24xx in USB Intel Neural Compute Stick and Intel Neural
Compute Stick 2 provides an API to accelerate AI inference calculations
on the dedicated SHAVE VLIW vector co-processors, which are orchestrated
by one or more LEON SPARC v8 real time cores.
However, they need firmware to be loaded beforehand. An uninitialised
Myriad ma24xx presents with a distinctive USB ID. After firmware
loading, the device detaches from the USB bus and reattaches with a new
device ID. It can then be claimed by the usermode driver.
Signed-off-by: Rhys Kidd <rhyskidd@xxxxxxxxx>
---
MAINTAINERS | 6 +
drivers/usb/misc/Kconfig | 8 ++
drivers/usb/misc/Makefile | 1 +
drivers/usb/misc/myriad-ma24xx-vsc.c | 171 +++++++++++++++++++++++++++
4 files changed, 186 insertions(+)
create mode 100644 drivers/usb/misc/myriad-ma24xx-vsc.c
diff --git a/MAINTAINERS b/MAINTAINERS
index a50e97a63bc8..2c3ab39ac26a 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -16682,6 +16682,12 @@ T: git git://git.kernel.org/pub/scm/linux/kernel/git/tiwai/sound.git
S: Maintained
F: sound/usb/midi.*
+USB MYRIAD MA24XX FIRMWARE DRIVER
+M: Rhys Kidd <rhyskidd@xxxxxxxxx>
+L: linux-usb@xxxxxxxxxxxxxxx
+S: Maintained
+F: drivers/usb/misc/myriad-ma24xx-vsc.c
+
USB NETWORKING DRIVERS
L: linux-usb@xxxxxxxxxxxxxxx
S: Odd Fixes
diff --git a/drivers/usb/misc/Kconfig b/drivers/usb/misc/Kconfig
index bdae62b2ffe0..5d600fb8ac50 100644
--- a/drivers/usb/misc/Kconfig
+++ b/drivers/usb/misc/Kconfig
@@ -275,3 +275,11 @@ config USB_CHAOSKEY
To compile this driver as a module, choose M here: the
module will be called chaoskey.
+
+config USB_MYRIAD_MA24XX_VSC
+ tristate "USB Intel Myriad MA24xx firmware loading support"
+ select FW_LOADER
+ help
+ This driver loads firmware for Myriad ma24xx AI inference accelerators, as
+ found in the USB Intel Neural Compute Stick (ma2450) and Intel Neural
+ Compute Stick 2 (ma2485).
\ No newline at end of file
diff --git a/drivers/usb/misc/Makefile b/drivers/usb/misc/Makefile
index 109f54f5b9aa..e19d1348c5b6 100644
--- a/drivers/usb/misc/Makefile
+++ b/drivers/usb/misc/Makefile
@@ -17,6 +17,7 @@ obj-$(CONFIG_USB_ISIGHTFW) += isight_firmware.o
obj-$(CONFIG_USB_LCD) += usblcd.o
obj-$(CONFIG_USB_LD) += ldusb.o
obj-$(CONFIG_USB_LEGOTOWER) += legousbtower.o
+obj-$(CONFIG_USB_MYRIAD_MA24XX_VSC) += myriad-ma24xx-vsc.o
obj-$(CONFIG_USB_RIO500) += rio500.o
obj-$(CONFIG_USB_TEST) += usbtest.o
obj-$(CONFIG_USB_EHSET_TEST_FIXTURE) += ehset.o
diff --git a/drivers/usb/misc/myriad-ma24xx-vsc.c b/drivers/usb/misc/myriad-ma24xx-vsc.c
new file mode 100644
index 000000000000..f516c236a8f5
--- /dev/null
+++ b/drivers/usb/misc/myriad-ma24xx-vsc.c
@@ -0,0 +1,171 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Driver for loading USB Myriad ma24xx firmware
+ *
+ * Copyright (C) 2018 Rhys Kidd <rhyskidd@xxxxxxxxx>
+ *
+ * The Myriad ma24xx in USB Intel Neural Compute Stick and Intel Neural
+ * Compute Stick 2 provides an API to accelerate AI inference calculations
+ * on the dedicated SHAVE VLIW vector co-processors, which are orchestrated
+ * by one or more LEON SPARC v8 real time cores.
+ *
+ * However, they need firmware to be loaded beforehand. An uninitialised
+ * Myriad ma24xx presents with a distinctive USB ID. After firmware
+ * loading, the device detaches from the USB bus and reattaches with a new
+ * device ID. It can then be claimed by the usermode driver.
+ *
+ * The firmware is non-free and must be extracted by the user.
+ */
+
+/* Standard include files */
+#include <linux/errno.h>
+#include <linux/firmware.h>
+#include <linux/module.h>
+#include <linux/slab.h>
+#include <linux/usb.h>
+
+#define usb_dbg(usb_if, format, arg...) \
+ dev_dbg(&(usb_if)->dev, format, ## arg)
+
+#define usb_err(usb_if, format, arg...) \
+ dev_err(&(usb_if)->dev, format, ## arg)
+
+/* Version Information */
+#define DRIVER_AUTHOR "Rhys Kidd <rhyskidd@xxxxxxxxx>"
+#define DRIVER_DESC "Driver for loading USB Myriad ma24xx firmware"
+#define DRIVER_SHORT "myriad_ma24xx_vsc"
+
+MODULE_AUTHOR(DRIVER_AUTHOR);
+MODULE_DESCRIPTION(DRIVER_DESC);
+MODULE_LICENSE("GPL");
+
+#define FW_DIR "myriad/"
+#define MA2450_FIRMWARE FW_DIR "mvncapi-2450.mvcmd"
+#define MA2480_FIRMWARE FW_DIR "mvncapi-2480.mvcmd"
+
+MODULE_FIRMWARE(MA2450_FIRMWARE);
+MODULE_FIRMWARE(MA2480_FIRMWARE);
+
+enum {
+ MA2450FW = 0,
+ MA2480FW
+};
+
+/* macros for struct usb_device_id */
+#define MYRIAD_CHIP_VERSION(x) \
+ ((x)->driver_info & 0xf)
+
+#define MYRIAD_VID 0x03e7 /* Movidius Ltd, an Intel company */
+#define MA2450_PID 0x2150 /* ma2450 VSC loopback device, without fw */
+#define MA2485_PID 0x2485 /* ma2485 VSC loopback device, without fw */
+
+#define MYRIAD_BUF_LEN 512 /* max size of USB_SPEED_HIGH packet */
+#define WRITE_TIMEOUT 2000 /* milliseconds */
+
+static const struct usb_device_id id_table[] = {
+ { USB_DEVICE(MYRIAD_VID, MA2450_PID), .driver_info = MA2450FW },
+ { USB_DEVICE(MYRIAD_VID, MA2485_PID), .driver_info = MA2480FW },
+ { },
+};
+MODULE_DEVICE_TABLE(usb, id_table);
+
+static int myriad_ma24xx_vsc_probe(struct usb_interface *intf,
+ const struct usb_device_id *id)
+{
+ struct usb_device *dev = interface_to_usbdev(intf);
+ struct usb_host_interface *altsetting = intf->cur_altsetting;
+ struct usb_endpoint_descriptor *epd;
+ int out_ep, res, size;
+ const struct firmware *firmware = NULL;
+ const u8 *ptr;
+ int offset, ret = 0;
+ char *buf;
+ char *fw_family_name;
+
+ usb_dbg(intf, "probe %s-%s", dev->product, dev->serial);
+
+ /* Find the first bulk OUT endpoint and its packet size */
+ res = usb_find_bulk_out_endpoint(altsetting, &epd);
+ if (res) {
+ usb_err(intf, "no OUT endpoint found");
+ return res;
+ }
+
+ out_ep = usb_endpoint_num(epd);
+ size = usb_endpoint_maxp(epd);
+
+ /* Validate endpoint and size */
+ if (size <= 0) {
+ usb_err(intf, "invalid size (%d)", size);
+ return -ENODEV;
+ }
+
+ if (size > MYRIAD_BUF_LEN) {
+ usb_dbg(intf, "size reduced %d -> %d\n", size, MYRIAD_BUF_LEN);
+ size = MYRIAD_BUF_LEN;
+ }
+
+ buf = kmalloc(size, GFP_KERNEL);
+ if (!buf)
+ return -ENOMEM;
+
+ switch (MYRIAD_CHIP_VERSION(id)) {
+ case MA2450FW:
+ fw_family_name = MA2450_FIRMWARE;
+ break;
+ case MA2480FW:
+ fw_family_name = MA2480_FIRMWARE;
+ break;
+ default:
+ usb_err(intf, "unsupported myriad ma24xx firmware family\n");
+ return -ENODEV;
+ }
+
+ if (request_firmware(&firmware, fw_family_name, &dev->dev) != 0) {
+ usb_err(intf, "unable to load myriad ma24xx firmware\n");
+ ret = -ENODEV;
+ goto out;
+ }
+
+ ptr = firmware->data;
+
+ /* Handle the sending of firmware */
+ usb_dbg(intf, "starting firmware load...\n");
+
+ for (offset = 0; offset < firmware->size; offset += size) {
+ int thislen = min_t(int, size, firmware->size - offset);
+
+ memcpy(buf, firmware->data + offset, thislen);
+
+ if (usb_bulk_msg(dev,
+ usb_sndbulkpipe(dev, out_ep),
+ buf,
+ thislen,
+ NULL,
+ WRITE_TIMEOUT) != 0) {
+ usb_err(intf, "failed to initialise myriad ma24xx firmware\n");
+ ret = -ENODEV;
+ goto out;
+ }
+ }
+ usb_dbg(intf, "firmware uploaded (%zu bytes)\n", firmware->size);
+
+out:
+ kfree(buf);
+ release_firmware(firmware);
+ return ret;
+}
+
+static void myriad_ma24xx_vsc_disconnect(struct usb_interface *intf)
+{
+}
+
+/* usb specific object needed to register this driver with the usb subsystem */
+static struct usb_driver myriad_ma24xx_vsc_driver = {
+ .name = DRIVER_SHORT,
+ .probe = myriad_ma24xx_vsc_probe,
+ .disconnect = myriad_ma24xx_vsc_disconnect,
+ .id_table = id_table,
+};
+
+module_usb_driver(myriad_ma24xx_vsc_driver);
--
2.20.1
