1 files changed, 756 insertions, 0 deletions

diff --git a/drivers/char/tpm/tpm_crb.c b/drivers/char/tpm/tpm_crb.c
new file mode 100644
index 000000000..20f271007
--- /dev/null
+++ b/drivers/char/tpm/tpm_crb.c
@@ -0,0 +1,756 @@
+/*
+ * Copyright (C) 2014 Intel Corporation
+ *
+ * Authors:
+ * Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
+ *
+ * Maintained by: <tpmdd-devel@lists.sourceforge.net>
+ *
+ * This device driver implements the TPM interface as defined in
+ * the TCG CRB 2.0 TPM specification.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; version 2
+ * of the License.
+ */
+
+#include <linux/acpi.h>
+#include <linux/highmem.h>
+#include <linux/rculist.h>
+#include <linux/module.h>
+#include <linux/pm_runtime.h>
+#ifdef CONFIG_ARM64
+#include <linux/arm-smccc.h>
+#endif
+#include "tpm.h"
+
+#define ACPI_SIG_TPM2 "TPM2"
+#define TPM_CRB_MAX_RESOURCES 3
+
+static const guid_t crb_acpi_start_guid =
+	GUID_INIT(0x6BBF6CAB, 0x5463, 0x4714,
+		  0xB7, 0xCD, 0xF0, 0x20, 0x3C, 0x03, 0x68, 0xD4);
+
+enum crb_defaults {
+	CRB_ACPI_START_REVISION_ID = 1,
+	CRB_ACPI_START_INDEX = 1,
+};
+
+enum crb_loc_ctrl {
+	CRB_LOC_CTRL_REQUEST_ACCESS	= BIT(0),
+	CRB_LOC_CTRL_RELINQUISH		= BIT(1),
+};
+
+enum crb_loc_state {
+	CRB_LOC_STATE_LOC_ASSIGNED	= BIT(1),
+	CRB_LOC_STATE_TPM_REG_VALID_STS	= BIT(7),
+};
+
+enum crb_ctrl_req {
+	CRB_CTRL_REQ_CMD_READY	= BIT(0),
+	CRB_CTRL_REQ_GO_IDLE	= BIT(1),
+};
+
+enum crb_ctrl_sts {
+	CRB_CTRL_STS_ERROR	= BIT(0),
+	CRB_CTRL_STS_TPM_IDLE	= BIT(1),
+};
+
+enum crb_start {
+	CRB_START_INVOKE	= BIT(0),
+};
+
+enum crb_cancel {
+	CRB_CANCEL_INVOKE	= BIT(0),
+};
+
+struct crb_regs_head {
+	u32 loc_state;
+	u32 reserved1;
+	u32 loc_ctrl;
+	u32 loc_sts;
+	u8 reserved2[32];
+	u64 intf_id;
+	u64 ctrl_ext;
+} __packed;
+
+struct crb_regs_tail {
+	u32 ctrl_req;
+	u32 ctrl_sts;
+	u32 ctrl_cancel;
+	u32 ctrl_start;
+	u32 ctrl_int_enable;
+	u32 ctrl_int_sts;
+	u32 ctrl_cmd_size;
+	u32 ctrl_cmd_pa_low;
+	u32 ctrl_cmd_pa_high;
+	u32 ctrl_rsp_size;
+	u64 ctrl_rsp_pa;
+} __packed;
+
+enum crb_status {
+	CRB_DRV_STS_COMPLETE	= BIT(0),
+};
+
+struct crb_priv {
+	u32 sm;
+	const char *hid;
+	struct crb_regs_head __iomem *regs_h;
+	struct crb_regs_tail __iomem *regs_t;
+	u8 __iomem *cmd;
+	u8 __iomem *rsp;
+	u32 cmd_size;
+	u32 smc_func_id;
+};
+
+struct tpm2_crb_smc {
+	u32 interrupt;
+	u8 interrupt_flags;
+	u8 op_flags;
+	u16 reserved2;
+	u32 smc_func_id;
+};
+
+static bool crb_wait_for_reg_32(u32 __iomem *reg, u32 mask, u32 value,
+				unsigned long timeout)
+{
+	ktime_t start;
+	ktime_t stop;
+
+	start = ktime_get();
+	stop = ktime_add(start, ms_to_ktime(timeout));
+
+	do {
+		if ((ioread32(reg) & mask) == value)
+			return true;
+
+		usleep_range(50, 100);
+	} while (ktime_before(ktime_get(), stop));
+
+	return ((ioread32(reg) & mask) == value);
+}
+
+/**
+ * __crb_go_idle - request tpm crb device to go the idle state
+ *
+ * @dev:  crb device
+ * @priv: crb private data
+ *
+ * Write CRB_CTRL_REQ_GO_IDLE to TPM_CRB_CTRL_REQ
+ * The device should respond within TIMEOUT_C by clearing the bit.
+ * Anyhow, we do not wait here as a consequent CMD_READY request
+ * will be handled correctly even if idle was not completed.
+ *
+ * The function does nothing for devices with ACPI-start method
+ * or SMC-start method.
+ *
+ * Return: 0 always
+ */
+static int __crb_go_idle(struct device *dev, struct crb_priv *priv)
+{
+	if ((priv->sm == ACPI_TPM2_START_METHOD) ||
+	    (priv->sm == ACPI_TPM2_COMMAND_BUFFER_WITH_START_METHOD) ||
+	    (priv->sm == ACPI_TPM2_COMMAND_BUFFER_WITH_ARM_SMC))
+		return 0;
+
+	iowrite32(CRB_CTRL_REQ_GO_IDLE, &priv->regs_t->ctrl_req);
+
+	if (!crb_wait_for_reg_32(&priv->regs_t->ctrl_req,
+				 CRB_CTRL_REQ_GO_IDLE/* mask */,
+				 0, /* value */
+				 TPM2_TIMEOUT_C)) {
+		dev_warn(dev, "goIdle timed out\n");
+		return -ETIME;
+	}
+
+	return 0;
+}
+
+static int crb_go_idle(struct tpm_chip *chip)
+{
+	struct device *dev = &chip->dev;
+	struct crb_priv *priv = dev_get_drvdata(dev);
+
+	return __crb_go_idle(dev, priv);
+}
+
+/**
+ * __crb_cmd_ready - request tpm crb device to enter ready state
+ *
+ * @dev:  crb device
+ * @priv: crb private data
+ *
+ * Write CRB_CTRL_REQ_CMD_READY to TPM_CRB_CTRL_REQ
+ * and poll till the device acknowledge it by clearing the bit.
+ * The device should respond within TIMEOUT_C.
+ *
+ * The function does nothing for devices with ACPI-start method
+ * or SMC-start method.
+ *
+ * Return: 0 on success -ETIME on timeout;
+ */
+static int __crb_cmd_ready(struct device *dev, struct crb_priv *priv)
+{
+	if ((priv->sm == ACPI_TPM2_START_METHOD) ||
+	    (priv->sm == ACPI_TPM2_COMMAND_BUFFER_WITH_START_METHOD) ||
+	    (priv->sm == ACPI_TPM2_COMMAND_BUFFER_WITH_ARM_SMC))
+		return 0;
+
+	iowrite32(CRB_CTRL_REQ_CMD_READY, &priv->regs_t->ctrl_req);
+	if (!crb_wait_for_reg_32(&priv->regs_t->ctrl_req,
+				 CRB_CTRL_REQ_CMD_READY /* mask */,
+				 0, /* value */
+				 TPM2_TIMEOUT_C)) {
+		dev_warn(dev, "cmdReady timed out\n");
+		return -ETIME;
+	}
+
+	return 0;
+}
+
+static int crb_cmd_ready(struct tpm_chip *chip)
+{
+	struct device *dev = &chip->dev;
+	struct crb_priv *priv = dev_get_drvdata(dev);
+
+	return __crb_cmd_ready(dev, priv);
+}
+
+static int __crb_request_locality(struct device *dev,
+				  struct crb_priv *priv, int loc)
+{
+	u32 value = CRB_LOC_STATE_LOC_ASSIGNED |
+		    CRB_LOC_STATE_TPM_REG_VALID_STS;
+
+	if (!priv->regs_h)
+		return 0;
+
+	iowrite32(CRB_LOC_CTRL_REQUEST_ACCESS, &priv->regs_h->loc_ctrl);
+	if (!crb_wait_for_reg_32(&priv->regs_h->loc_state, value, value,
+				 TPM2_TIMEOUT_C)) {
+		dev_warn(dev, "TPM_LOC_STATE_x.requestAccess timed out\n");
+		return -ETIME;
+	}
+
+	return 0;
+}
+
+static int crb_request_locality(struct tpm_chip *chip, int loc)
+{
+	struct crb_priv *priv = dev_get_drvdata(&chip->dev);
+
+	return __crb_request_locality(&chip->dev, priv, loc);
+}
+
+static int __crb_relinquish_locality(struct device *dev,
+				     struct crb_priv *priv, int loc)
+{
+	u32 mask = CRB_LOC_STATE_LOC_ASSIGNED |
+		   CRB_LOC_STATE_TPM_REG_VALID_STS;
+	u32 value = CRB_LOC_STATE_TPM_REG_VALID_STS;
+
+	if (!priv->regs_h)
+		return 0;
+
+	iowrite32(CRB_LOC_CTRL_RELINQUISH, &priv->regs_h->loc_ctrl);
+	if (!crb_wait_for_reg_32(&priv->regs_h->loc_state, mask, value,
+				 TPM2_TIMEOUT_C)) {
+		dev_warn(dev, "TPM_LOC_STATE_x.requestAccess timed out\n");
+		return -ETIME;
+	}
+
+	return 0;
+}
+
+static int crb_relinquish_locality(struct tpm_chip *chip, int loc)
+{
+	struct crb_priv *priv = dev_get_drvdata(&chip->dev);
+
+	return __crb_relinquish_locality(&chip->dev, priv, loc);
+}
+
+static u8 crb_status(struct tpm_chip *chip)
+{
+	struct crb_priv *priv = dev_get_drvdata(&chip->dev);
+	u8 sts = 0;
+
+	if ((ioread32(&priv->regs_t->ctrl_start) & CRB_START_INVOKE) !=
+	    CRB_START_INVOKE)
+		sts |= CRB_DRV_STS_COMPLETE;
+
+	return sts;
+}
+
+static int crb_recv(struct tpm_chip *chip, u8 *buf, size_t count)
+{
+	struct crb_priv *priv = dev_get_drvdata(&chip->dev);
+	unsigned int expected;
+
+	/* A sanity check that the upper layer wants to get at least the header
+	 * as that is the minimum size for any TPM response.
+	 */
+	if (count < TPM_HEADER_SIZE)
+		return -EIO;
+
+	/* If this bit is set, according to the spec, the TPM is in
+	 * unrecoverable condition.
+	 */
+	if (ioread32(&priv->regs_t->ctrl_sts) & CRB_CTRL_STS_ERROR)
+		return -EIO;
+
+	/* Read the first 8 bytes in order to get the length of the response.
+	 * We read exactly a quad word in order to make sure that the remaining
+	 * reads will be aligned.
+	 */
+	memcpy_fromio(buf, priv->rsp, 8);
+
+	expected = be32_to_cpup((__be32 *)&buf[2]);
+	if (expected > count || expected < TPM_HEADER_SIZE)
+		return -EIO;
+
+	memcpy_fromio(&buf[8], &priv->rsp[8], expected - 8);
+
+	return expected;
+}
+
+static int crb_do_acpi_start(struct tpm_chip *chip)
+{
+	union acpi_object *obj;
+	int rc;
+
+	obj = acpi_evaluate_dsm(chip->acpi_dev_handle,
+				&crb_acpi_start_guid,
+				CRB_ACPI_START_REVISION_ID,
+				CRB_ACPI_START_INDEX,
+				NULL);
+	if (!obj)
+		return -ENXIO;
+	rc = obj->integer.value == 0 ? 0 : -ENXIO;
+	ACPI_FREE(obj);
+	return rc;
+}
+
+#ifdef CONFIG_ARM64
+/*
+ * This is a TPM Command Response Buffer start method that invokes a
+ * Secure Monitor Call to requrest the firmware to execute or cancel
+ * a TPM 2.0 command.
+ */
+static int tpm_crb_smc_start(struct device *dev, unsigned long func_id)
+{
+	struct arm_smccc_res res;
+
+	arm_smccc_smc(func_id, 0, 0, 0, 0, 0, 0, 0, &res);
+	if (res.a0 != 0) {
+		dev_err(dev,
+			FW_BUG "tpm_crb_smc_start() returns res.a0 = 0x%lx\n",
+			res.a0);
+		return -EIO;
+	}
+
+	return 0;
+}
+#else
+static int tpm_crb_smc_start(struct device *dev, unsigned long func_id)
+{
+	dev_err(dev, FW_BUG "tpm_crb: incorrect start method\n");
+	return -EINVAL;
+}
+#endif
+
+static int crb_send(struct tpm_chip *chip, u8 *buf, size_t len)
+{
+	struct crb_priv *priv = dev_get_drvdata(&chip->dev);
+	int rc = 0;
+
+	/* Zero the cancel register so that the next command will not get
+	 * canceled.
+	 */
+	iowrite32(0, &priv->regs_t->ctrl_cancel);
+
+	if (len > priv->cmd_size) {
+		dev_err(&chip->dev, "invalid command count value %zd %d\n",
+			len, priv->cmd_size);
+		return -E2BIG;
+	}
+
+	memcpy_toio(priv->cmd, buf, len);
+
+	/* Make sure that cmd is populated before issuing start. */
+	wmb();
+
+	/* The reason for the extra quirk is that the PTT in 4th Gen Core CPUs
+	 * report only ACPI start but in practice seems to require both
+	 * CRB start, hence invoking CRB start method if hid == MSFT0101.
+	 */
+	if ((priv->sm == ACPI_TPM2_COMMAND_BUFFER) ||
+	    (priv->sm == ACPI_TPM2_MEMORY_MAPPED) ||
+	    (!strcmp(priv->hid, "MSFT0101")))
+		iowrite32(CRB_START_INVOKE, &priv->regs_t->ctrl_start);
+
+	if ((priv->sm == ACPI_TPM2_START_METHOD) ||
+	    (priv->sm == ACPI_TPM2_COMMAND_BUFFER_WITH_START_METHOD))
+		rc = crb_do_acpi_start(chip);
+
+	if (priv->sm == ACPI_TPM2_COMMAND_BUFFER_WITH_ARM_SMC) {
+		iowrite32(CRB_START_INVOKE, &priv->regs_t->ctrl_start);
+		rc = tpm_crb_smc_start(&chip->dev, priv->smc_func_id);
+	}
+
+	return rc;
+}
+
+static void crb_cancel(struct tpm_chip *chip)
+{
+	struct crb_priv *priv = dev_get_drvdata(&chip->dev);
+
+	iowrite32(CRB_CANCEL_INVOKE, &priv->regs_t->ctrl_cancel);
+
+	if (((priv->sm == ACPI_TPM2_START_METHOD) ||
+	    (priv->sm == ACPI_TPM2_COMMAND_BUFFER_WITH_START_METHOD)) &&
+	     crb_do_acpi_start(chip))
+		dev_err(&chip->dev, "ACPI Start failed\n");
+}
+
+static bool crb_req_canceled(struct tpm_chip *chip, u8 status)
+{
+	struct crb_priv *priv = dev_get_drvdata(&chip->dev);
+	u32 cancel = ioread32(&priv->regs_t->ctrl_cancel);
+
+	return (cancel & CRB_CANCEL_INVOKE) == CRB_CANCEL_INVOKE;
+}
+
+static const struct tpm_class_ops tpm_crb = {
+	.flags = TPM_OPS_AUTO_STARTUP,
+	.status = crb_status,
+	.recv = crb_recv,
+	.send = crb_send,
+	.cancel = crb_cancel,
+	.req_canceled = crb_req_canceled,
+	.go_idle  = crb_go_idle,
+	.cmd_ready = crb_cmd_ready,
+	.request_locality = crb_request_locality,
+	.relinquish_locality = crb_relinquish_locality,
+	.req_complete_mask = CRB_DRV_STS_COMPLETE,
+	.req_complete_val = CRB_DRV_STS_COMPLETE,
+};
+
+static int crb_check_resource(struct acpi_resource *ares, void *data)
+{
+	struct resource *iores_array = data;
+	struct resource_win win;
+	struct resource *res = &(win.res);
+	int i;
+
+	if (acpi_dev_resource_memory(ares, res) ||
+	    acpi_dev_resource_address_space(ares, &win)) {
+		for (i = 0; i < TPM_CRB_MAX_RESOURCES + 1; ++i) {
+			if (resource_type(iores_array + i) != IORESOURCE_MEM) {
+				iores_array[i] = *res;
+				iores_array[i].name = NULL;
+				break;
+			}
+		}
+	}
+
+	return 1;
+}
+
+static void __iomem *crb_map_res(struct device *dev, struct resource *iores,
+				 void __iomem **iobase_ptr, u64 start, u32 size)
+{
+	struct resource new_res = {
+		.start	= start,
+		.end	= start + size - 1,
+		.flags	= IORESOURCE_MEM,
+	};
+
+	/* Detect a 64 bit address on a 32 bit system */
+	if (start != new_res.start)
+		return (void __iomem *) ERR_PTR(-EINVAL);
+
+	if (!iores)
+		return devm_ioremap_resource(dev, &new_res);
+
+	if (!*iobase_ptr) {
+		*iobase_ptr = devm_ioremap_resource(dev, iores);
+		if (IS_ERR(*iobase_ptr))
+			return *iobase_ptr;
+	}
+
+	return *iobase_ptr + (new_res.start - iores->start);
+}
+
+/*
+ * Work around broken BIOSs that return inconsistent values from the ACPI
+ * region vs the registers. Trust the ACPI region. Such broken systems
+ * probably cannot send large TPM commands since the buffer will be truncated.
+ */
+static u64 crb_fixup_cmd_size(struct device *dev, struct resource *io_res,
+			      u64 start, u64 size)
+{
+	if (io_res->start > start || io_res->end < start)
+		return size;
+
+	if (start + size - 1 <= io_res->end)
+		return size;
+
+	dev_err(dev,
+		FW_BUG "ACPI region does not cover the entire command/response buffer. %pr vs %llx %llx\n",
+		io_res, start, size);
+
+	return io_res->end - start + 1;
+}
+
+static int crb_map_io(struct acpi_device *device, struct crb_priv *priv,
+		      struct acpi_table_tpm2 *buf)
+{
+	struct list_head acpi_resource_list;
+	struct resource iores_array[TPM_CRB_MAX_RESOURCES + 1] = { {0} };
+	void __iomem *iobase_array[TPM_CRB_MAX_RESOURCES] = {NULL};
+	struct device *dev = &device->dev;
+	struct resource *iores;
+	void __iomem **iobase_ptr;
+	int i;
+	u32 pa_high, pa_low;
+	u64 cmd_pa;
+	u32 cmd_size;
+	__le64 __rsp_pa;
+	u64 rsp_pa;
+	u32 rsp_size;
+	int ret;
+
+	INIT_LIST_HEAD(&acpi_resource_list);
+	ret = acpi_dev_get_resources(device, &acpi_resource_list,
+				     crb_check_resource, iores_array);
+	if (ret < 0)
+		return ret;
+	acpi_dev_free_resource_list(&acpi_resource_list);
+
+	if (resource_type(iores_array) != IORESOURCE_MEM) {
+		dev_err(dev, FW_BUG "TPM2 ACPI table does not define a memory resource\n");
+		return -EINVAL;
+	} else if (resource_type(iores_array + TPM_CRB_MAX_RESOURCES) ==
+		IORESOURCE_MEM) {
+		dev_warn(dev, "TPM2 ACPI table defines too many memory resources\n");
+		memset(iores_array + TPM_CRB_MAX_RESOURCES,
+		       0, sizeof(*iores_array));
+		iores_array[TPM_CRB_MAX_RESOURCES].flags = 0;
+	}
+
+	iores = NULL;
+	iobase_ptr = NULL;
+	for (i = 0; resource_type(iores_array + i) == IORESOURCE_MEM; ++i) {
+		if (buf->control_address >= iores_array[i].start &&
+		    buf->control_address + sizeof(struct crb_regs_tail) - 1 <=
+		    iores_array[i].end) {
+			iores = iores_array + i;
+			iobase_ptr = iobase_array + i;
+			break;
+		}
+	}
+
+	priv->regs_t = crb_map_res(dev, iores, iobase_ptr, buf->control_address,
+				   sizeof(struct crb_regs_tail));
+
+	if (IS_ERR(priv->regs_t))
+		return PTR_ERR(priv->regs_t);
+
+	/* The ACPI IO region starts at the head area and continues to include
+	 * the control area, as one nice sane region except for some older
+	 * stuff that puts the control area outside the ACPI IO region.
+	 */
+	if ((priv->sm == ACPI_TPM2_COMMAND_BUFFER) ||
+	    (priv->sm == ACPI_TPM2_MEMORY_MAPPED)) {
+		if (iores &&
+		    buf->control_address == iores->start +
+		    sizeof(*priv->regs_h))
+			priv->regs_h = *iobase_ptr;
+		else
+			dev_warn(dev, FW_BUG "Bad ACPI memory layout");
+	}
+
+	ret = __crb_request_locality(dev, priv, 0);
+	if (ret)
+		return ret;
+
+	/*
+	 * PTT HW bug w/a: wake up the device to access
+	 * possibly not retained registers.
+	 */
+	ret = __crb_cmd_ready(dev, priv);
+	if (ret)
+		goto out_relinquish_locality;
+
+	pa_high = ioread32(&priv->regs_t->ctrl_cmd_pa_high);
+	pa_low  = ioread32(&priv->regs_t->ctrl_cmd_pa_low);
+	cmd_pa = ((u64)pa_high << 32) | pa_low;
+	cmd_size = ioread32(&priv->regs_t->ctrl_cmd_size);
+
+	iores = NULL;
+	iobase_ptr = NULL;
+	for (i = 0; iores_array[i].end; ++i) {
+		if (cmd_pa >= iores_array[i].start &&
+		    cmd_pa <= iores_array[i].end) {
+			iores = iores_array + i;
+			iobase_ptr = iobase_array + i;
+			break;
+		}
+	}
+
+	if (iores)
+		cmd_size = crb_fixup_cmd_size(dev, iores, cmd_pa, cmd_size);
+
+	dev_dbg(dev, "cmd_hi = %X cmd_low = %X cmd_size %X\n",
+		pa_high, pa_low, cmd_size);
+
+	priv->cmd = crb_map_res(dev, iores, iobase_ptr,	cmd_pa, cmd_size);
+	if (IS_ERR(priv->cmd)) {
+		ret = PTR_ERR(priv->cmd);
+		goto out;
+	}
+
+	memcpy_fromio(&__rsp_pa, &priv->regs_t->ctrl_rsp_pa, 8);
+	rsp_pa = le64_to_cpu(__rsp_pa);
+	rsp_size = ioread32(&priv->regs_t->ctrl_rsp_size);
+
+	iores = NULL;
+	iobase_ptr = NULL;
+	for (i = 0; resource_type(iores_array + i) == IORESOURCE_MEM; ++i) {
+		if (rsp_pa >= iores_array[i].start &&
+		    rsp_pa <= iores_array[i].end) {
+			iores = iores_array + i;
+			iobase_ptr = iobase_array + i;
+			break;
+		}
+	}
+
+	if (iores)
+		rsp_size = crb_fixup_cmd_size(dev, iores, rsp_pa, rsp_size);
+
+	if (cmd_pa != rsp_pa) {
+		priv->rsp = crb_map_res(dev, iores, iobase_ptr,
+					rsp_pa, rsp_size);
+		ret = PTR_ERR_OR_ZERO(priv->rsp);
+		goto out;
+	}
+
+	/* According to the PTP specification, overlapping command and response
+	 * buffer sizes must be identical.
+	 */
+	if (cmd_size != rsp_size) {
+		dev_err(dev, FW_BUG "overlapping command and response buffer sizes are not identical");
+		ret = -EINVAL;
+		goto out;
+	}
+
+	priv->rsp = priv->cmd;
+
+out:
+	if (!ret)
+		priv->cmd_size = cmd_size;
+
+	__crb_go_idle(dev, priv);
+
+out_relinquish_locality:
+
+	__crb_relinquish_locality(dev, priv, 0);
+
+	return ret;
+}
+
+static int crb_acpi_add(struct acpi_device *device)
+{
+	struct acpi_table_tpm2 *buf;
+	struct crb_priv *priv;
+	struct tpm_chip *chip;
+	struct device *dev = &device->dev;
+	struct tpm2_crb_smc *crb_smc;
+	acpi_status status;
+	u32 sm;
+	int rc;
+
+	status = acpi_get_table(ACPI_SIG_TPM2, 1,
+				(struct acpi_table_header **) &buf);
+	if (ACPI_FAILURE(status) || buf->header.length < sizeof(*buf)) {
+		dev_err(dev, FW_BUG "failed to get TPM2 ACPI table\n");
+		return -EINVAL;
+	}
+
+	/* Should the FIFO driver handle this? */
+	sm = buf->start_method;
+	if (sm == ACPI_TPM2_MEMORY_MAPPED)
+		return -ENODEV;
+
+	priv = devm_kzalloc(dev, sizeof(struct crb_priv), GFP_KERNEL);
+	if (!priv)
+		return -ENOMEM;
+
+	if (sm == ACPI_TPM2_COMMAND_BUFFER_WITH_ARM_SMC) {
+		if (buf->header.length < (sizeof(*buf) + sizeof(*crb_smc))) {
+			dev_err(dev,
+				FW_BUG "TPM2 ACPI table has wrong size %u for start method type %d\n",
+				buf->header.length,
+				ACPI_TPM2_COMMAND_BUFFER_WITH_ARM_SMC);
+			return -EINVAL;
+		}
+		crb_smc = ACPI_ADD_PTR(struct tpm2_crb_smc, buf, sizeof(*buf));
+		priv->smc_func_id = crb_smc->smc_func_id;
+	}
+
+	priv->sm = sm;
+	priv->hid = acpi_device_hid(device);
+
+	rc = crb_map_io(device, priv, buf);
+	if (rc)
+		return rc;
+
+	chip = tpmm_chip_alloc(dev, &tpm_crb);
+	if (IS_ERR(chip))
+		return PTR_ERR(chip);
+
+	dev_set_drvdata(&chip->dev, priv);
+	chip->acpi_dev_handle = device->handle;
+	chip->flags = TPM_CHIP_FLAG_TPM2;
+
+	return tpm_chip_register(chip);
+}
+
+static int crb_acpi_remove(struct acpi_device *device)
+{
+	struct device *dev = &device->dev;
+	struct tpm_chip *chip = dev_get_drvdata(dev);
+
+	tpm_chip_unregister(chip);
+
+	return 0;
+}
+
+static const struct dev_pm_ops crb_pm = {
+	SET_SYSTEM_SLEEP_PM_OPS(tpm_pm_suspend, tpm_pm_resume)
+};
+
+static const struct acpi_device_id crb_device_ids[] = {
+	{"MSFT0101", 0},
+	{"", 0},
+};
+MODULE_DEVICE_TABLE(acpi, crb_device_ids);
+
+static struct acpi_driver crb_acpi_driver = {
+	.name = "tpm_crb",
+	.ids = crb_device_ids,
+	.ops = {
+		.add = crb_acpi_add,
+		.remove = crb_acpi_remove,
+	},
+	.drv = {
+		.pm = &crb_pm,
+	},
+};
+
+module_acpi_driver(crb_acpi_driver);
+MODULE_AUTHOR("Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>");
+MODULE_DESCRIPTION("TPM2 Driver");
+MODULE_VERSION("0.1");
+MODULE_LICENSE("GPL");