This commit adds a driver for the Xaptum ENF Access Card, a TPM2.0
hardware module for authenticating IoT devices and gateways.
The card consists of a SPI TPM 2.0 chip and a USB-SPI bridge. This
driver configures the bridge, registers the bridge as an SPI
controller, and adds the TPM 2.0 as an SPI device. The in-kernel TPM
2.0 driver is then automatically loaded to configure the TPM and
expose it to userspace.
Signed-off-by: David R. Bild <david.bild@xxxxxxxxxx>
---
MAINTAINERS | 6 +
drivers/usb/misc/Kconfig | 2 +
drivers/usb/misc/Makefile | 1 +
drivers/usb/misc/xapea00x/Kconfig | 14 +
drivers/usb/misc/xapea00x/Makefile | 7 +
drivers/usb/misc/xapea00x/xapea00x-bridge.c | 380 ++++++++++++++++++++++++++
drivers/usb/misc/xapea00x/xapea00x-core.c | 408 ++++++++++++++++++++++++++++
drivers/usb/misc/xapea00x/xapea00x-spi.c | 196 +++++++++++++
drivers/usb/misc/xapea00x/xapea00x.h | 75 +++++
9 files changed, 1089 insertions(+)
create mode 100644 drivers/usb/misc/xapea00x/Kconfig
create mode 100644 drivers/usb/misc/xapea00x/Makefile
create mode 100644 drivers/usb/misc/xapea00x/xapea00x-bridge.c
create mode 100644 drivers/usb/misc/xapea00x/xapea00x-core.c
create mode 100644 drivers/usb/misc/xapea00x/xapea00x-spi.c
create mode 100644 drivers/usb/misc/xapea00x/xapea00x.h
diff --git a/MAINTAINERS b/MAINTAINERS
index b1ccabd0dbc3..77d35444ef1c 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -14796,6 +14796,12 @@ L: linux-wireless@xxxxxxxxxxxxxxx
S: Maintained
F: drivers/net/wireless/rndis_wlan.c
+USB XAPEA00X DRIVER
+M: David R. Bild <david.bild@xxxxxxxxxx>
+L: linux-usb@xxxxxxxxxxxxxxx
+S: Maintained
+F: drivers/usb/misc/xapea00x/
+
USB XHCI DRIVER
M: Mathias Nyman <mathias.nyman@xxxxxxxxx>
L: linux-usb@xxxxxxxxxxxxxxx
diff --git a/drivers/usb/misc/Kconfig b/drivers/usb/misc/Kconfig
index 68d2f2cd17dd..747d7f03fb84 100644
--- a/drivers/usb/misc/Kconfig
+++ b/drivers/usb/misc/Kconfig
@@ -275,3 +275,5 @@ config USB_CHAOSKEY
To compile this driver as a module, choose M here: the
module will be called chaoskey.
+
+source "drivers/usb/misc/xapea00x/Kconfig"
diff --git a/drivers/usb/misc/Makefile b/drivers/usb/misc/Makefile
index 109f54f5b9aa..f3583501547c 100644
--- a/drivers/usb/misc/Makefile
+++ b/drivers/usb/misc/Makefile
@@ -30,4 +30,5 @@ obj-$(CONFIG_USB_HSIC_USB4604) += usb4604.o
obj-$(CONFIG_USB_CHAOSKEY) += chaoskey.o
obj-$(CONFIG_USB_SISUSBVGA) += sisusbvga/
+obj-$(CONFIG_USB_XAPEA00X) += xapea00x/
obj-$(CONFIG_USB_LINK_LAYER_TEST) += lvstest.o
diff --git a/drivers/usb/misc/xapea00x/Kconfig b/drivers/usb/misc/xapea00x/Kconfig
new file mode 100644
index 000000000000..bea57c8cca53
--- /dev/null
+++ b/drivers/usb/misc/xapea00x/Kconfig
@@ -0,0 +1,14 @@
+config USB_XAPEA00X
+ tristate "Xaptum ENF Access card support (XAP-EA-00x)"
+ depends on USB_SUPPORT && SPI && TCG_TPM
+ select TCG_TIS_SPI
+ help
+ Say Y here if you want to support the Xaptum ENF Access
+ modules (XAP-EA-00x) in the USB or Mini PCI-e form
+ factors. The XAP-EA-00x module exposes a TPM 2.0 as
+ /dev/tpmX to use for authenticating with the Xaptum ENF.
+
+ To compile this driver as a module, choose M here. The
+ module will be called xapea00x.
+
+ If unsure, say M.
diff --git a/drivers/usb/misc/xapea00x/Makefile b/drivers/usb/misc/xapea00x/Makefile
new file mode 100644
index 000000000000..c4bcd7524c31
--- /dev/null
+++ b/drivers/usb/misc/xapea00x/Makefile
@@ -0,0 +1,7 @@
+# SPDX-License-Identifier: GPL-2.0
+#
+# Makefile for the xapea00x driver.
+#
+obj-$(CONFIG_USB_XAPEA00X) += xapea00x.o
+
+xapea00x-y += xapea00x-core.o xapea00x-bridge.o
diff --git a/drivers/usb/misc/xapea00x/xapea00x-bridge.c b/drivers/usb/misc/xapea00x/xapea00x-bridge.c
new file mode 100644
index 000000000000..7071431dea96
--- /dev/null
+++ b/drivers/usb/misc/xapea00x/xapea00x-bridge.c
@@ -0,0 +1,380 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Driver for the XAP-EA-00x series of the Xaptum Edge Access Card, a
+ * TPM 2.0-based hardware module for authenticating IoT devices and
+ * gateways.
+ *
+ * Copyright (c) 2017-2018 Xaptum, Inc.
+ */
+
+#include "xapea00x.h"
+
+#define XAPEA00X_BR_CMD_READ 0x00
+#define XAPEA00X_BR_CMD_WRITE 0x01
+#define XAPEA00X_BR_CMD_WRITEREAD 0x02
+
+#define XAPEA00X_BR_BREQTYP_SET 0x40
+
+#define XAPEA00X_BR_BREQ_SET_GPIO_VALUES 0x21
+#define XAPEA00X_BR_BREQ_SET_GPIO_CS 0x25
+#define XAPEA00X_BR_BREQ_SET_SPI_WORD 0x31
+
+#define XAPEA00X_BR_USB_TIMEOUT 1000 // msecs
+
+#define XAPEA00X_BR_CS_DISABLED 0x00
+
+/*******************************************************************************
+ * Bridge USB transfers
+ */
+
+struct xapea00x_br_bulk_command {
+ __u16 reserved1;
+ __u8 command;
+ __u8 reserved2;
+ __le32 length;
+} __attribute__((__packed__));
+
+/**
+ * xapea00x_br_prep_bulk_command - Prepares the bulk command header with
+ * the supplied values.
+ * @hdr: pointer to header to prepare
+ * @command: the command id for the command
+ * @length: length in bytes of the command data
+ *
+ * Context: !in_interrupt()
+ *
+ * Return: If successful, 0. Otherwise a negative error number.
+ */
+static void xapea00x_br_prep_bulk_command(struct xapea00x_br_bulk_command *hdr,
+ u8 command, int length)
+{
+ hdr->reserved1 = 0;
+ hdr->command = command;
+ hdr->reserved2 = 0;
+ hdr->length = __cpu_to_le32(length);
+}
+
+/**
+ * xapea00x_br_bulk_write - Issues a bulk write to the bridge chip.
+ * @dev: pointer to the device to write to
+ * @command: the command started by this write (WRITE, READ, WRITE_READ)
+ * @data: pointer to the data to write. Must be DMA capable (e.g.,
+ * kmalloc-ed, not stack).
+ * @len: length in bytes of the data to write
+ *
+ * Context: !in_interrupt()
+ *
+ * Return: If successful, 0. Otherwise a negative error number.
+ */
+static int xapea00x_br_bulk_write(struct xapea00x_device *dev,
+ struct xapea00x_br_bulk_command *header,
+ const void *data, int len)
+{
+ u8 *buf;
+ unsigned int pipe;
+ int buf_len, actual_len, retval;
+
+ buf_len = sizeof(struct xapea00x_br_bulk_command) + len;
+ buf = kzalloc(buf_len, GFP_KERNEL);
+ if (!buf) {
+ retval = -ENOMEM;
+ goto out;
+ }
+
+ memcpy(buf, header, sizeof(struct xapea00x_br_bulk_command));
+ memcpy(buf + sizeof(struct xapea00x_br_bulk_command), data, len);
+
+ pipe = usb_sndbulkpipe(dev->udev, dev->bulk_out->bEndpointAddress);
+ retval = usb_bulk_msg(dev->udev, pipe, buf, buf_len, &actual_len,
+ XAPEA00X_BR_USB_TIMEOUT);
+ if (retval)
+ goto free_buf;
+
+free_buf:
+ kzfree(buf);
+
+out:
+ return retval;
+}
+
+/**
+ * xapea00x_br_bulk_read - Issues a bulk read to the bridge chip.
+ * @dev: pointer to the device to read from
+ * @data: pointer to the data read. Must be DMA capable (e.g.,
+ * kmalloc-ed, not stack).
+ * @len: length in bytes of the data to read
+ *
+ * Return: If successful, 0. Otherwise a negative error code.
+ */
+static int xapea00x_br_bulk_read(struct xapea00x_device *dev, void *data,
+ int len)
+{
+ unsigned int pipe;
+ void *buf;
+ int actual_len, retval;
+
+ buf = kzalloc(len, GFP_KERNEL);
+ if (!buf) {
+ retval = -ENOMEM;
+ goto out;
+ }
+
+ pipe = usb_rcvbulkpipe(dev->udev, dev->bulk_in->bEndpointAddress);
+ retval = usb_bulk_msg(dev->udev, pipe, buf, len, &actual_len,
+ XAPEA00X_BR_USB_TIMEOUT);
+
+ if (retval)
+ goto free_buf;
+
+ memcpy(data, buf, actual_len);
+
+free_buf:
+ kzfree(buf);
+
+out:
+ return retval;
+}
+
+/**
+ * xapea00x_br_ctrl_write - Issues a send control transfer to the bridge
+ * chip.
+ * @dev: pointer to the device to write to
+ * @bRequest: the command
+ * @wValue: the command value
+ * @wIndex: the command index
+ * @data: pointer to the command data
+ * @len: length in bytes of the command data
+ *
+ * The possible bRequest, wValue, and wIndex values and data format
+ * are specified in the hardware datasheet.
+ *
+ * Context: !in_interrupt()
+ *
+ * Return: If successful, 0. Otherwise a negative error code.
+ */
+static int xapea00x_br_ctrl_write(struct xapea00x_device *dev, u8 bRequest,
+ u16 wValue, u16 wIndex, u8 *data, u16 len)
+{
+ unsigned int pipe;
+ void *buf;
+ int retval;
+
+ buf = kzalloc(len, GFP_KERNEL);
+ if (!buf) {
+ retval = -ENOMEM;
+ goto out;
+ }
+ memcpy(buf, data, len);
+
+ pipe = usb_sndctrlpipe(dev->udev, 0);
+ retval = usb_control_msg(dev->udev, pipe, bRequest,
+ XAPEA00X_BR_BREQTYP_SET, wValue, wIndex,
+ buf, len, XAPEA00X_BR_USB_TIMEOUT);
+ if (retval < 0)
+ goto free_buf;
+
+ retval = 0;
+
+free_buf:
+ kzfree(buf);
+
+out:
+ return retval;
+}
+
+/*******************************************************************************
+ * Bridge configuration commands
+ */
+
+/**
+ * xapea00x_br_set_gpio_value - Sets the value on the specified pin of
+ * the bridge chip.
+ * @dev: pointer to the device containing the bridge whose pin to set
+ * @pin: the number of the pin to set
+ * @value: the value to set the pin to, 0 or 1
+ *
+ * Context: !in_interrupt()
+ *
+ * Return: If successful, 0. Otherwise a negative error number.
+ */
+static int xapea00x_br_set_gpio_value(struct xapea00x_device *dev, u8 pin,
+ u8 value)
+{
+ u8 data[4] = { 0, 0, 0, 0 };
+
+ switch (pin) {
+ case 10:
+ case 9:
+ case 8:
+ case 7:
+ case 6:
+ data[0] = value << (pin - 4);
+ data[2] = 1 << (pin - 4);
+ break;
+ case 5:
+ data[0] = value;
+ data[2] = 1;
+ break;
+ case 4:
+ case 3:
+ case 2:
+ case 1:
+ case 0:
+ data[1] = value << (pin + 3);
+ data[3] = 1 << (pin + 3);
+ break;
+ }
+ return xapea00x_br_ctrl_write(dev, XAPEA00X_BR_BREQ_SET_GPIO_VALUES,
+ 0, 0, data, 4);
+}
+
+/**
+ * xapea00x_br_set_gpio_cs - Sets the chip select control on the specified
+ * pin of the bridge chip.
+ * @dev: pointer to the device containing the bridge whose cs to set
+ * @pin: the number of the pin to set
+ * @control: the chip select control value for the pin, 0, 1, or 2
+ *
+ * Context: !in_interrupt()
+ *
+ * Return: If successful, 0. Otherwise a negative error number.
+ */
+static int xapea00x_br_set_gpio_cs(struct xapea00x_device *dev, u8 pin,
+ u8 control)
+{
+ u8 data[2] = { pin, control };
+
+ return xapea00x_br_ctrl_write(dev, XAPEA00X_BR_BREQ_SET_GPIO_CS,
+ 0, 0, data, 2);
+}
+
+/*******************************************************************************
+ * Bridge configuration commands
+ */
+/**
+ * xapea00x_br_disable_cs - disable the built-in chip select
+ * capability of the specified channel. It does not support holding
+ * the CS active between SPI transfers, a feature required for the
+ * TPM. Instead, we manually control the CS pin as a GPIO.
+ * @dev: pointer to the device containing the bridge whose cs to disable
+ * @channel: the SPI channel whose cs to disable
+ *
+ * Context: !in_interrupt()
+ *
+ * Return: If successful 0. Otherwise a negative error number.
+ */
+int xapea00x_br_disable_cs(struct xapea00x_device *dev, u8 channel)
+{
+ return xapea00x_br_set_gpio_cs(dev, channel,
+ XAPEA00X_BR_CS_DISABLED);
+}
+
+/**
+ * xapea00x_br_assert_cs - assert the chip select pin for the
+ * specified channel.
+ * @dev: pointer to the device containing the bridge who cs to assert
+ * @channel: the SPI channel whose cs to assert
+ *
+ * Context: !in_interrupt()
+ *
+ * Return: If successful 0. Otherwise a negative error number.
+ */
+int xapea00x_br_assert_cs(struct xapea00x_device *dev, u8 channel)
+{
+ return xapea00x_br_set_gpio_value(dev, channel, 0);
+}
+
+/**
+ * xapea00x_br_deassert_cs - deassert the chip select pin for the
+ * specified channel.
+ * @dev: pointer to the device containing the bridge who cs to deassert
+ * @channel: the SPI channel whose cs to deassert
+ *
+ * Context: !in_interrupt()
+ *
+ * Return: If successful 0. Otherwise a negative error number.
+ */
+int xapea00x_br_deassert_cs(struct xapea00x_device *dev, u8 channel)
+{
+ return xapea00x_br_set_gpio_value(dev, channel, 1);
+}
+
+/*******************************************************************************
+ * Bridge SPI reads and writes
+ */
+/**
+ * xeapea00x_spi_read - Performs a read from the active channel
+ * @dev: pointer to the device to perform the read
+ * @rx_buf: pointer to the buffer to read the data into. Must be
+ * DMA-capable (e.g., kmalloc-ed, not stack).
+ * @len: length in bytes of the data to read
+ *
+ * Context: !in_interrupt()
+ *
+ * Return: If successful, 0. Otherwise a negative error number.
+ */
+int xapea00x_br_spi_read(struct xapea00x_device *dev, void *rx_buf, int len)
+{
+ struct xapea00x_br_bulk_command header;
+ int retval;
+
+ xapea00x_br_prep_bulk_command(&header, XAPEA00X_BR_CMD_READ, len);
+ retval = xapea00x_br_bulk_write(dev, &header, NULL, 0);
+ if (retval)
+ goto out;
+
+ retval = xapea00x_br_bulk_read(dev, rx_buf, len);
+
+out:
+ return retval;
+}
+
+/**
+ *xapea00x_br_spi_write - Performs a write to the active channel
+ * @dev: pointer to the device to perform the write
+ * @tx_buf: pointer to the data to write. Must be DMA-capable (e.g.,
+ * kmalloc-ed, not stack).
+ * @len: length in bytes of the data to write
+ */
+int xapea00x_br_spi_write(struct xapea00x_device *dev, const void *tx_buf,
+ int len)
+{
+ struct xapea00x_br_bulk_command header;
+ int retval;
+
+ xapea00x_br_prep_bulk_command(&header, XAPEA00X_BR_CMD_WRITE, len);
+ retval = xapea00x_br_bulk_write(dev, &header, tx_buf, len);
+
+ return retval;
+}
+
+/**
+ * xapea00x_br_spi_write_read - Performs a simultaneous write and read on
+ * the active channel
+ * @dev: pointer to the device to perform the write/read
+ * @tx_buf: pointer to the data to write. Must be DMA-capable (e.g.,
+ * kmalloc-ed, not stack).
+ * @rx_buf: pointer to the buffer to read the data into. Must be
+ * DMA-capable (e.g., kmalloc-ed, not stack).
+ * @len: length in bytes of the data to write/read
+ *
+ * Context: !in_interrupt()
+ *
+ * Return: If successful, 0. Otherwise a negative error number.
+ */
+int xapea00x_br_spi_write_read(struct xapea00x_device *dev, const void *tx_buf,
+ void *rx_buf, int len)
+{
+ struct xapea00x_br_bulk_command header;
+ int retval;
+
+ xapea00x_br_prep_bulk_command(&header, XAPEA00X_BR_CMD_WRITEREAD, len);
+ retval = xapea00x_br_bulk_write(dev, &header, tx_buf, len);
+ if (retval)
+ goto out;
+
+ retval = xapea00x_br_bulk_read(dev, rx_buf, len);
+
+out:
+ return retval;
+}
diff --git a/drivers/usb/misc/xapea00x/xapea00x-core.c b/drivers/usb/misc/xapea00x/xapea00x-core.c
new file mode 100644
index 000000000000..885bcda9c01d
--- /dev/null
+++ b/drivers/usb/misc/xapea00x/xapea00x-core.c
@@ -0,0 +1,408 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Driver for the XAP-EA-00x series of the Xaptum Edge Access Card, a
+ * TPM 2.0-based hardware module for authenticating IoT devices and
+ * gateways.
+ *
+ * Copyright (c) 2017-2018 Xaptum, Inc.
+ */
+
+#include "xapea00x.h"
+
+#define XAPEA00X_TPM_MODALIAS "tpm_tis_spi"
+
+#define kref_to_xapea00x(k) container_of(k, struct xapea00x_device, kref)
+
+static void xapea00x_delete(struct kref *kref)
+{
+ struct xapea00x_device *dev = kref_to_xapea00x(kref);
+
+ usb_put_dev(dev->udev);
+ kfree(dev);
+}
+
+/*******************************************************************************
+ * SPI master functions
+ */
+
+/**
+ * xapea00x_spi_setup - Setup the SPI channel for the TPM.
+ *
+ * Context: !in_interrupt()
+ *
+ * Return: If successful, 0. Otherwise a negative error number.
+ */
+static int xapea00x_spi_setup(struct spi_device *spi)
+{
+ struct xapea00x_device *dev;
+ int retval;
+
+ dev = spi_master_get_devdata(spi->master);
+
+ mutex_lock(&dev->usb_mutex);
+ if (!dev->interface) {
+ retval = -ENODEV;
+ goto out;
+ }
+
+ /* Verify that this is the TPM device */
+ if (spi->chip_select != 0) {
+ retval = -EINVAL;
+ goto err;
+ }
+
+ /*
+ * Disable auto chip select for the TPM channel.
+ * Must be done after setting the SPI parameters.
+ */
+ retval = xapea00x_br_disable_cs(dev, 0);
+ if (retval)
+ goto err;
+
+ /* De-assert chip select for the TPM channel. */
+ retval = xapea00x_br_deassert_cs(dev, 0);
+ if (retval)
+ goto err;
+
+ goto out;
+
+err:
+ dev_err(&dev->interface->dev,
+ "configuring SPI channel failed with %d\n", retval);
+
+out:
+ mutex_unlock(&dev->usb_mutex);
+ return retval;
+}
+
+/**
+ * xapea00x_spi_transfer - Execute a single SPI transfer.
+ * @dev: pointer to the device to do the transfer on
+ * @tx_buf: pointer to the data to send, if not NULL
+ * @rx_buf: pointer to the buffer to store the received data, if not NULL
+ * @len: length in bytes of the data to send/receive
+ * @cs_hold: If non-zero, the chip select will remain asserted
+ * @delay_usecs: If nonzero, how long to delay after last bit transfer
+ *
+ * Context: !in_interrupt()
+ *
+ * Return: If successful, 0. Otherwise a negative error number.
+ */
+int xapea00x_spi_transfer(struct xapea00x_device *dev,
+ const void *tx_buf, void *rx_buf, u32 len,
+ int cs_hold, u16 delay_usecs)
+{
+ int retval;
+
+ /* Assert chip select */
+ retval = xapea00x_br_assert_cs(dev, 0);
+ if (retval)
+ goto out;
+
+ /* empty transfer */
+ if (!tx_buf && !rx_buf)
+ retval = 0;
+ /* read transfer */
+ else if (!tx_buf)
+ retval = xapea00x_br_spi_read(dev, rx_buf, len);
+ /* write transfer */
+ else if (!rx_buf)
+ retval = xapea00x_br_spi_write(dev, tx_buf, len);
+ /* write_read transfer */
+ else
+ retval = xapea00x_br_spi_write_read(dev, tx_buf, rx_buf, len);
+
+ /* Deassert chip select, if requested */
+ if (!cs_hold)
+ retval = xapea00x_br_deassert_cs(dev, 0);
+
+ /* Delay for the requested time */
+ udelay(delay_usecs);
+
+out:
+ return retval;
+}
+
+/**
+ * xapea00x_spi_transfer_one_message - Execute a full SPI message.
+ * @master: The SPI master on which to execute the message.
+ * @msg: The SPI message to execute.
+ *
+ * Context: !in_interrupt()
+ *
+ * Return: If successful, 0. Otherwise a negative erorr number.
+ */
+static int xapea00x_spi_transfer_one_message(struct spi_master *master,
+ struct spi_message *msg)
+{
+ struct xapea00x_device *dev;
+ struct spi_transfer *xfer;
+ int is_last, retval;
+
+ dev = spi_master_get_devdata(master);
+
+ mutex_lock(&dev->usb_mutex);
+ if (!dev->interface) {
+ retval = -ENODEV;
+ goto out;
+ }
+
+ /* perform all transfers */
+ list_for_each_entry(xfer, &msg->transfers, transfer_list) {
+ is_last = list_is_last(&xfer->transfer_list, &msg->transfers);
+
+ /* Transfer message */
+ retval = xapea00x_spi_transfer(dev, xfer->tx_buf,
+ xfer->rx_buf, xfer->len,
+ is_last == xfer->cs_change,
+ xfer->delay_usecs);
+ if (retval)
+ goto out;
+
+ msg->actual_length += xfer->len;
+ }
+
+ retval = 0;
+
+out:
+ msg->status = retval;
+ spi_finalize_current_message(master);
+
+ mutex_unlock(&dev->usb_mutex);
+ return retval;
+}
+
+/**
+ * xapea00x_spi_probe - Register and configure the SPI master.
+ * @dev: the device whose SPI master to register
+ *
+ * Return: If successful, 0. Otherwise a negative error number.
+ */
+static int xapea00x_spi_probe(struct xapea00x_device *dev)
+{
+ struct spi_master *spi_master;
+ int retval;
+
+ spi_master = spi_alloc_master(&dev->interface->dev, sizeof(void *));
+ if (!spi_master) {
+ retval = -ENOMEM;
+ goto err_out;
+ }
+
+ spi_master_set_devdata(spi_master, dev);
+
+ spi_master->min_speed_hz = 93 * 1000 + 800; /* 93.9kHz */
+ spi_master->max_speed_hz = 12 * 1000 * 1000; /* 12 MHz */
+
+ spi_master->bus_num = -1; /* dynamically assigned */
+ spi_master->num_chipselect = 1;
+ spi_master->mode_bits = SPI_MODE_0;
+
+ spi_master->flags = 0;
+ spi_master->setup = xapea00x_spi_setup;
+ spi_master->transfer_one_message = xapea00x_spi_transfer_one_message;
+
+ retval = spi_register_master(spi_master);
+
+ if (retval)
+ goto free_spi;
+
+ dev->spi_master = spi_master;
+
+ return 0;
+
+free_spi:
+ spi_master_put(spi_master);
+ dev->spi_master = NULL;
+
+err_out:
+ return retval;
+}
+
+struct xapea00x_async_probe {
+ struct work_struct work;
+ struct xapea00x_device *dev;
+};
+
+#define work_to_probe(w) container_of(w, struct xapea00x_async_probe, work)
+
+/**
+ * xapea00x_init_async_probe - initialize an async probe with the
+ * specified values.
+ * @probe: pointer to the async_probe to initialize
+ * @dev: pointer to the device to probe
+ * @f: pointer to the probe function
+ */
+static void xapea00x_init_async_probe(struct xapea00x_async_probe *probe,
+ struct xapea00x_device *dev,
+ void (*f)(struct work_struct *work))
+{
+ INIT_WORK(&probe->work, f);
+ probe->dev = dev;
+
+ kref_get(&dev->kref);
+ spi_master_get(dev->spi_master);
+}
+
+/**
+ * xapea00x_cleanup_async_probe - clean up the internals of the async
+ * probe. Call this method after the probe has completed.
+ *
+ * The caller is responsible for freeing the probe itself, if
+ * dynamically allocated.
+ *
+ * @probe: pointer to the async_probe to clean up
+ */
+static void xapea00x_cleanup_async_probe(struct xapea00x_async_probe *probe)
+{
+ spi_master_put(probe->dev->spi_master);
+ kref_put(&probe->dev->kref, xapea00x_delete);
+}
+
+static struct spi_board_info tpm_board_info = {
+ .modalias = XAPEA00X_TPM_MODALIAS,
+ .max_speed_hz = 43 * 1000 * 1000, // Hz
+ .chip_select = 0,
+ .mode = SPI_MODE_0
+};
+
+/**
+ * xapea00x_tpm_probe - Register and initialize the TPM device
+ * @work: the work struct contained by the xapea00x device
+ *
+ * Context: !in_interrupt()
+ */
+static void xapea00x_tpm_probe(struct work_struct *work)
+{
+ struct xapea00x_async_probe *probe = work_to_probe(work);
+ struct xapea00x_device *dev = probe->dev;
+ struct spi_master *spi_master = dev->spi_master;
+ struct spi_device *tpm;
+ int retval;
+
+ tpm = spi_new_device(spi_master, &tpm_board_info);
+ mutex_lock(&dev->usb_mutex);
+ if (!dev->interface) {
+ retval = -ENODEV;
+ goto out;
+ }
+ if (!tpm) {
+ retval = -ENODEV;
+ dev_err(&dev->interface->dev,
+ "unable to add spi device for TPM\n");
+ goto err;
+ }
+
+ dev->tpm = tpm;
+ goto out;
+
+err:
+ dev_err(&dev->interface->dev,
+ "TPM initialization failed with %d\n", retval);
+
+out:
+ mutex_unlock(&dev->usb_mutex);
+ xapea00x_cleanup_async_probe(probe);
+ kzfree(probe);
+}
+
+/*******************************************************************************
+ * USB driver structs and functions
+ */
+
+static const struct usb_device_id xapea00x_devices[] = {
+ { USB_DEVICE(USB_VENDOR_ID_SILABS, USB_PRODUCT_ID_XAPEA001) },
+ { USB_DEVICE(USB_VENDOR_ID_XAPTUM, USB_PRODUCT_ID_XAPEA002) },
+ { USB_DEVICE(USB_VENDOR_ID_XAPTUM, USB_PRODUCT_ID_XAPEA003) },
+ { }
+};
+MODULE_DEVICE_TABLE(usb, xapea00x_devices);
+
+static int xapea00x_probe(struct usb_interface *interface,
+ const struct usb_device_id *id)
+{
+ struct xapea00x_device *dev;
+ struct xapea00x_async_probe *probe;
+ int retval;
+
+ dev = kzalloc(sizeof(*dev), GFP_KERNEL);
+ if (!dev)
+ return -ENOMEM;
+
+ kref_init(&dev->kref);
+ mutex_init(&dev->usb_mutex);
+
+ /* ---------------------- USB ------------------------ */
+ dev->interface = interface;
+ dev->udev = usb_get_dev(interface_to_usbdev(interface));
+
+ dev->vid = __le16_to_cpu(dev->udev->descriptor.idVendor);
+ dev->pid = __le16_to_cpu(dev->udev->descriptor.idProduct);
+
+ retval = usb_find_common_endpoints(interface->cur_altsetting,
+ &dev->bulk_in, &dev->bulk_out,
+ NULL, NULL);
+ if (retval) {
+ dev_err(&interface->dev,
+ "could not find both bulk-in and bulk-out endpoints\n");
+ goto free_dev;
+ }
+
+ usb_set_intfdata(interface, dev);
+
+ /* ---------------------- SPI Master ------------------------ */
+ retval = xapea00x_spi_probe(dev);
+ if (retval) {
+ dev_err(&interface->dev, "could not initialize SPI master\n");
+ goto free_dev;
+ }
+
+ /* ---------------------- TPM SPI Device ------------------------ */
+ probe = kzalloc(sizeof(*probe), GFP_KERNEL);
+ if (!probe) {
+ retval = -ENOMEM;
+ goto free_spi;
+ }
+ xapea00x_init_async_probe(probe, dev, xapea00x_tpm_probe);
+
+ schedule_work(&probe->work);
+
+ /* ---------------------- Finished ------------------------ */
+ return 0;
+
+free_spi:
+ spi_unregister_master(dev->spi_master);
+
+free_dev:
+ kref_put(&dev->kref, xapea00x_delete);
+
+ dev_err(&interface->dev, "device failed with %d\n", retval);
+ return retval;
+}
+
+static void xapea00x_disconnect(struct usb_interface *interface)
+{
+ struct xapea00x_device *dev = usb_get_intfdata(interface);
+
+ usb_set_intfdata(interface, NULL);
+ spi_unregister_master(dev->spi_master);
+
+ mutex_lock(&dev->usb_mutex);
+ dev->interface = NULL;
+ mutex_unlock(&dev->usb_mutex);
+
+ kref_put(&dev->kref, xapea00x_delete);
+}
+
+static struct usb_driver xapea00x_driver = {
+ .name = KBUILD_MODNAME,
+ .probe = xapea00x_probe,
+ .disconnect = xapea00x_disconnect,
+ .id_table = xapea00x_devices
+};
+
+module_usb_driver(xapea00x_driver);
+
+MODULE_AUTHOR("David R. Bild <david.bild@xxxxxxxxxx>");
+MODULE_DESCRIPTION("Xaptum XAP-EA-00x ENF Access card");
+MODULE_LICENSE("GPL");
diff --git a/drivers/usb/misc/xapea00x/xapea00x-spi.c b/drivers/usb/misc/xapea00x/xapea00x-spi.c
new file mode 100644
index 000000000000..d71e79029639
--- /dev/null
+++ b/drivers/usb/misc/xapea00x/xapea00x-spi.c
@@ -0,0 +1,196 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Driver for the XAP-EA-00x series of the Xaptum Edge Access Card, a
+ * TPM 2.0-based hardware module for authenticating IoT devices and
+ * gateways.
+ *
+ * Copyright (c) 2017-2018 Xaptum, Inc.
+ */
+
+#include "xapea00x.h"
+
+/*******************************************************************************
+ * SPI master functions
+ */
+
+/**
+ * xapea00x_spi_setup - Setup the SPI channel for the TPM.
+ *
+ * Context: !in_interrupt()
+ *
+ * Return: If successful, 0. Otherwise a negative error number.
+ */
+static int xapea00x_spi_setup(struct spi_device *spi)
+{
+ struct xapea00x_device *dev;
+ int retval;
+
+ dev = spi_master_get_devdata(spi->master);
+
+ /* Verify that this is the TPM device */
+ if (spi->chip_select != 0) {
+ retval = -EINVAL;
+ goto err;
+ }
+
+ /* Set the SPI parameters for the TPM channel. */
+ retval = xapea00x_br_set_spi_word(dev, 0, XAPEA00X_TPM_SPI_WORD);
+ if (retval)
+ goto err;
+
+ /*
+ * Disable auto chip select for the TPM channel.
+ * Must be done after setting the SPI parameters.
+ */
+ retval = xapea00x_br_set_gpio_cs(dev, 0, XAPEA00X_GPIO_CS_DISABLED);
+ if (retval)
+ goto err;
+
+ /* De-assert chip select for the TPM channel. */
+ retval = xapea00x_br_set_gpio_value(dev, 0, 1);
+ if (retval)
+ goto err;
+
+ return 0;
+
+err:
+ dev_err(&dev->interface->dev,
+ "configuring SPI channel failed with %d\n", retval);
+ return retval;
+}
+
+/**
+ * xapea00x_spi_transfer - Execute a single SPI transfer.
+ * @dev: pointer to the device to do the transfer on
+ * @tx_buf: pointer to the data to send, if not NULL
+ * @rx_buf: pointer to the buffer to store the received data, if not NULL
+ * @len: length in bytes of the data to send/receive
+ * @cs_hold: If non-zero, the chip select will remain asserted
+ * @delay_usecs: If nonzero, how long to delay after last bit transfer
+ *
+ * Context: !in_interrupt()
+ *
+ * Return: If successful, 0. Otherwise a negative error number.
+ */
+int xapea00x_spi_transfer(struct xapea00x_device *dev,
+ const void *tx_buf, void *rx_buf, u32 len,
+ int cs_hold, u16 delay_usecs)
+{
+ int retval;
+
+ /* Assert chip select */
+ retval = xapea00x_br_set_gpio_value(dev, 0, 0);
+ if (retval)
+ goto out;
+
+ /* empty transfer */
+ if (!tx_buf && !rx_buf)
+ retval = 0;
+ /* read transfer */
+ else if (!tx_buf)
+ retval = xapea00x_br_spi_read(dev, rx_buf, len);
+ /* write transfer */
+ else if (!rx_buf)
+ retval = xapea00x_br_spi_write(dev, tx_buf, len);
+ /* write_read transfer */
+ else
+ retval = xapea00x_br_spi_write_read(dev, tx_buf, rx_buf, len);
+
+ /* Deassert chip select, if requested */
+ if (!cs_hold)
+ retval = xapea00x_br_set_gpio_value(dev, 0, 1);
+
+ /* Delay for the requested time */
+ udelay(delay_usecs);
+
+out:
+ return retval;
+}
+
+/**
+ * xapea00x_spi_transfer_one_message - Execute a full SPI message.
+ * @master: The SPI master on which to execute the message.
+ * @msg: The SPI message to execute.
+ *
+ * Context: !in_interrupt()
+ *
+ * Return: If successful, 0. Otherwise a negative erorr number.
+ */
+static int xapea00x_spi_transfer_one_message(struct spi_master *master,
+ struct spi_message *msg)
+{
+ struct xapea00x_device *dev;
+ struct spi_transfer *xfer;
+ int is_last, retval;
+
+ dev = spi_master_get_devdata(master);
+
+ /* perform all transfers */
+ list_for_each_entry(xfer, &msg->transfers, transfer_list) {
+ is_last = list_is_last(&xfer->transfer_list, &msg->transfers);
+
+ /* Transfer message */
+ retval = xapea00x_spi_transfer(dev, xfer->tx_buf,
+ xfer->rx_buf, xfer->len,
+ is_last == xfer->cs_change,
+ xfer->delay_usecs);
+ if (retval)
+ goto out;
+
+ msg->actual_length += xfer->len;
+ }
+
+ retval = 0;
+
+out:
+ msg->status = retval;
+ spi_finalize_current_message(master);
+ return retval;
+}
+
+/**
+ * xapea00x_spi_probe - Register and configure the SPI master.
+ * @dev: the device whose SPI master to register
+ *
+ * Return: If successful, 0. Otherwise a negative error number.
+ */
+static int xapea00x_spi_probe(struct xapea00x_device *dev)
+{
+ struct spi_master *spi_master;
+ int retval;
+
+ spi_master = spi_alloc_master(&dev->udev->dev, sizeof(void *));
+ if (!spi_master) {
+ retval = -ENOMEM;
+ goto err_out;
+ }
+
+ spi_master_set_devdata(spi_master, dev);
+
+ spi_master->min_speed_hz = 93 * 1000 + 800; /* 93.9kHz */
+ spi_master->max_speed_hz = 12 * 1000 * 1000; /* 12 MHz */
+
+ spi_master->bus_num = -1; /* dynamically assigned */
+ spi_master->num_chipselect = XAPEA00X_NUM_CS;
+ spi_master->mode_bits = SPI_MODE_0;
+
+ spi_master->flags = 0;
+ spi_master->setup = xapea00x_spi_setup;
+ spi_master->transfer_one_message = xapea00x_spi_transfer_one_message;
+
+ retval = spi_register_master(spi_master);
+
+ if (retval)
+ goto free_spi;
+
+ dev->spi_master = spi_master;
+
+ return 0;
+
+free_spi:
+ spi_master_put(spi_master);
+ dev->spi_master = NULL;
+
+err_out:
+ return retval;
+}
diff --git a/drivers/usb/misc/xapea00x/xapea00x.h b/drivers/usb/misc/xapea00x/xapea00x.h
new file mode 100644
index 000000000000..4771a9af71e3
--- /dev/null
+++ b/drivers/usb/misc/xapea00x/xapea00x.h
@@ -0,0 +1,75 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Driver for the XAP-EA-00x series of the Xaptum Edge Access Card, a
+ * TPM 2.0-based hardware module for authenticating IoT devices and
+ * gateways.
+ *
+ * Copyright (c) 2017-2018 Xaptum, Inc.
+ */
+
+#ifndef _XAPEA00X_H
+#define _XAPEA00X_H
+
+#include <linux/kernel.h>
+#include <linux/kref.h>
+#include <linux/module.h>
+#include <linux/mutex.h>
+#include <linux/slab.h>
+#include <linux/spi/spi.h>
+#include <linux/usb.h>
+#include <linux/workqueue.h>
+
+#define USB_VENDOR_ID_SILABS 0x10c4
+#define USB_VENDOR_ID_XAPTUM 0x2FE0
+
+#define USB_PRODUCT_ID_XAPEA001 0x8BDE
+#define USB_PRODUCT_ID_XAPEA002 0x8BDE
+#define USB_PRODUCT_ID_XAPEA003 0x8BEE
+
+struct xapea00x_device {
+ struct kref kref;
+
+ struct usb_device *udev;
+ /*
+ * The interface pointer will be set NULL when the device
+ * disconnects. Accessing it safe only while holding the
+ * usb_mutex.
+ */
+ struct usb_interface *interface;
+ /*
+ * Th usb_mutex must be held while synchronous USB requests are
+ * in progress. It is acquired during disconnect to be sure
+ * that there is not an outstanding request.
+ */
+ struct mutex usb_mutex;
+
+ struct usb_endpoint_descriptor *bulk_in;
+ struct usb_endpoint_descriptor *bulk_out;
+
+ u16 pid;
+ u16 vid;
+
+ struct spi_master *spi_master;
+ struct spi_device *tpm;
+};
+
+/* Public bridge functions */
+int xapea00x_br_disable_cs(struct xapea00x_device *dev, u8 channel);
+int xapea00x_br_assert_cs(struct xapea00x_device *dev, u8 channel);
+int xapea00x_br_deassert_cs(struct xapea00x_device *dev, u8 channel);
+
+int xapea00x_br_spi_read(struct xapea00x_device *dev, void *rx_buf, int len);
+int xapea00x_br_spi_write(struct xapea00x_device *dev, const void *tx_buf,
+ int len);
+int xapea00x_br_spi_write_read(struct xapea00x_device *dev, const void *tx_buf,
+ void *rx_buf, int len);
+
+/* Shared SPI function */
+int xapea00x_spi_transfer(struct xapea00x_device *dev,
+ const void *tx_buf, void *rx_buf, u32 len,
+ int cs_hold, u16 delay_usecs);
+
+/* Shared TPM functions */
+int xapea00x_tpm_platform_initialize(struct xapea00x_device *dev);
+
+#endif /* _XAPEA00X_H */
--
2.16.3
