cachepc-linux

Fork of AMDESE/linux with modifications for CachePC side-channel attack
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tpm_crb.c (18581B)


      1// SPDX-License-Identifier: GPL-2.0-only
      2/*
      3 * Copyright (C) 2014 Intel Corporation
      4 *
      5 * Authors:
      6 * Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
      7 *
      8 * Maintained by: <tpmdd-devel@lists.sourceforge.net>
      9 *
     10 * This device driver implements the TPM interface as defined in
     11 * the TCG CRB 2.0 TPM specification.
     12 */
     13
     14#include <linux/acpi.h>
     15#include <linux/highmem.h>
     16#include <linux/rculist.h>
     17#include <linux/module.h>
     18#include <linux/pm_runtime.h>
     19#ifdef CONFIG_ARM64
     20#include <linux/arm-smccc.h>
     21#endif
     22#include "tpm.h"
     23
     24#define ACPI_SIG_TPM2 "TPM2"
     25#define TPM_CRB_MAX_RESOURCES 3
     26
     27static const guid_t crb_acpi_start_guid =
     28	GUID_INIT(0x6BBF6CAB, 0x5463, 0x4714,
     29		  0xB7, 0xCD, 0xF0, 0x20, 0x3C, 0x03, 0x68, 0xD4);
     30
     31enum crb_defaults {
     32	CRB_ACPI_START_REVISION_ID = 1,
     33	CRB_ACPI_START_INDEX = 1,
     34};
     35
     36enum crb_loc_ctrl {
     37	CRB_LOC_CTRL_REQUEST_ACCESS	= BIT(0),
     38	CRB_LOC_CTRL_RELINQUISH		= BIT(1),
     39};
     40
     41enum crb_loc_state {
     42	CRB_LOC_STATE_LOC_ASSIGNED	= BIT(1),
     43	CRB_LOC_STATE_TPM_REG_VALID_STS	= BIT(7),
     44};
     45
     46enum crb_ctrl_req {
     47	CRB_CTRL_REQ_CMD_READY	= BIT(0),
     48	CRB_CTRL_REQ_GO_IDLE	= BIT(1),
     49};
     50
     51enum crb_ctrl_sts {
     52	CRB_CTRL_STS_ERROR	= BIT(0),
     53	CRB_CTRL_STS_TPM_IDLE	= BIT(1),
     54};
     55
     56enum crb_start {
     57	CRB_START_INVOKE	= BIT(0),
     58};
     59
     60enum crb_cancel {
     61	CRB_CANCEL_INVOKE	= BIT(0),
     62};
     63
     64struct crb_regs_head {
     65	u32 loc_state;
     66	u32 reserved1;
     67	u32 loc_ctrl;
     68	u32 loc_sts;
     69	u8 reserved2[32];
     70	u64 intf_id;
     71	u64 ctrl_ext;
     72} __packed;
     73
     74struct crb_regs_tail {
     75	u32 ctrl_req;
     76	u32 ctrl_sts;
     77	u32 ctrl_cancel;
     78	u32 ctrl_start;
     79	u32 ctrl_int_enable;
     80	u32 ctrl_int_sts;
     81	u32 ctrl_cmd_size;
     82	u32 ctrl_cmd_pa_low;
     83	u32 ctrl_cmd_pa_high;
     84	u32 ctrl_rsp_size;
     85	u64 ctrl_rsp_pa;
     86} __packed;
     87
     88enum crb_status {
     89	CRB_DRV_STS_COMPLETE	= BIT(0),
     90};
     91
     92struct crb_priv {
     93	u32 sm;
     94	const char *hid;
     95	struct crb_regs_head __iomem *regs_h;
     96	struct crb_regs_tail __iomem *regs_t;
     97	u8 __iomem *cmd;
     98	u8 __iomem *rsp;
     99	u32 cmd_size;
    100	u32 smc_func_id;
    101};
    102
    103struct tpm2_crb_smc {
    104	u32 interrupt;
    105	u8 interrupt_flags;
    106	u8 op_flags;
    107	u16 reserved2;
    108	u32 smc_func_id;
    109};
    110
    111static bool crb_wait_for_reg_32(u32 __iomem *reg, u32 mask, u32 value,
    112				unsigned long timeout)
    113{
    114	ktime_t start;
    115	ktime_t stop;
    116
    117	start = ktime_get();
    118	stop = ktime_add(start, ms_to_ktime(timeout));
    119
    120	do {
    121		if ((ioread32(reg) & mask) == value)
    122			return true;
    123
    124		usleep_range(50, 100);
    125	} while (ktime_before(ktime_get(), stop));
    126
    127	return ((ioread32(reg) & mask) == value);
    128}
    129
    130/**
    131 * __crb_go_idle - request tpm crb device to go the idle state
    132 *
    133 * @dev:  crb device
    134 * @priv: crb private data
    135 *
    136 * Write CRB_CTRL_REQ_GO_IDLE to TPM_CRB_CTRL_REQ
    137 * The device should respond within TIMEOUT_C by clearing the bit.
    138 * Anyhow, we do not wait here as a consequent CMD_READY request
    139 * will be handled correctly even if idle was not completed.
    140 *
    141 * The function does nothing for devices with ACPI-start method
    142 * or SMC-start method.
    143 *
    144 * Return: 0 always
    145 */
    146static int __crb_go_idle(struct device *dev, struct crb_priv *priv)
    147{
    148	if ((priv->sm == ACPI_TPM2_START_METHOD) ||
    149	    (priv->sm == ACPI_TPM2_COMMAND_BUFFER_WITH_START_METHOD) ||
    150	    (priv->sm == ACPI_TPM2_COMMAND_BUFFER_WITH_ARM_SMC))
    151		return 0;
    152
    153	iowrite32(CRB_CTRL_REQ_GO_IDLE, &priv->regs_t->ctrl_req);
    154
    155	if (!crb_wait_for_reg_32(&priv->regs_t->ctrl_req,
    156				 CRB_CTRL_REQ_GO_IDLE/* mask */,
    157				 0, /* value */
    158				 TPM2_TIMEOUT_C)) {
    159		dev_warn(dev, "goIdle timed out\n");
    160		return -ETIME;
    161	}
    162
    163	return 0;
    164}
    165
    166static int crb_go_idle(struct tpm_chip *chip)
    167{
    168	struct device *dev = &chip->dev;
    169	struct crb_priv *priv = dev_get_drvdata(dev);
    170
    171	return __crb_go_idle(dev, priv);
    172}
    173
    174/**
    175 * __crb_cmd_ready - request tpm crb device to enter ready state
    176 *
    177 * @dev:  crb device
    178 * @priv: crb private data
    179 *
    180 * Write CRB_CTRL_REQ_CMD_READY to TPM_CRB_CTRL_REQ
    181 * and poll till the device acknowledge it by clearing the bit.
    182 * The device should respond within TIMEOUT_C.
    183 *
    184 * The function does nothing for devices with ACPI-start method
    185 * or SMC-start method.
    186 *
    187 * Return: 0 on success -ETIME on timeout;
    188 */
    189static int __crb_cmd_ready(struct device *dev, struct crb_priv *priv)
    190{
    191	if ((priv->sm == ACPI_TPM2_START_METHOD) ||
    192	    (priv->sm == ACPI_TPM2_COMMAND_BUFFER_WITH_START_METHOD) ||
    193	    (priv->sm == ACPI_TPM2_COMMAND_BUFFER_WITH_ARM_SMC))
    194		return 0;
    195
    196	iowrite32(CRB_CTRL_REQ_CMD_READY, &priv->regs_t->ctrl_req);
    197	if (!crb_wait_for_reg_32(&priv->regs_t->ctrl_req,
    198				 CRB_CTRL_REQ_CMD_READY /* mask */,
    199				 0, /* value */
    200				 TPM2_TIMEOUT_C)) {
    201		dev_warn(dev, "cmdReady timed out\n");
    202		return -ETIME;
    203	}
    204
    205	return 0;
    206}
    207
    208static int crb_cmd_ready(struct tpm_chip *chip)
    209{
    210	struct device *dev = &chip->dev;
    211	struct crb_priv *priv = dev_get_drvdata(dev);
    212
    213	return __crb_cmd_ready(dev, priv);
    214}
    215
    216static int __crb_request_locality(struct device *dev,
    217				  struct crb_priv *priv, int loc)
    218{
    219	u32 value = CRB_LOC_STATE_LOC_ASSIGNED |
    220		    CRB_LOC_STATE_TPM_REG_VALID_STS;
    221
    222	if (!priv->regs_h)
    223		return 0;
    224
    225	iowrite32(CRB_LOC_CTRL_REQUEST_ACCESS, &priv->regs_h->loc_ctrl);
    226	if (!crb_wait_for_reg_32(&priv->regs_h->loc_state, value, value,
    227				 TPM2_TIMEOUT_C)) {
    228		dev_warn(dev, "TPM_LOC_STATE_x.requestAccess timed out\n");
    229		return -ETIME;
    230	}
    231
    232	return 0;
    233}
    234
    235static int crb_request_locality(struct tpm_chip *chip, int loc)
    236{
    237	struct crb_priv *priv = dev_get_drvdata(&chip->dev);
    238
    239	return __crb_request_locality(&chip->dev, priv, loc);
    240}
    241
    242static int __crb_relinquish_locality(struct device *dev,
    243				     struct crb_priv *priv, int loc)
    244{
    245	u32 mask = CRB_LOC_STATE_LOC_ASSIGNED |
    246		   CRB_LOC_STATE_TPM_REG_VALID_STS;
    247	u32 value = CRB_LOC_STATE_TPM_REG_VALID_STS;
    248
    249	if (!priv->regs_h)
    250		return 0;
    251
    252	iowrite32(CRB_LOC_CTRL_RELINQUISH, &priv->regs_h->loc_ctrl);
    253	if (!crb_wait_for_reg_32(&priv->regs_h->loc_state, mask, value,
    254				 TPM2_TIMEOUT_C)) {
    255		dev_warn(dev, "TPM_LOC_STATE_x.requestAccess timed out\n");
    256		return -ETIME;
    257	}
    258
    259	return 0;
    260}
    261
    262static int crb_relinquish_locality(struct tpm_chip *chip, int loc)
    263{
    264	struct crb_priv *priv = dev_get_drvdata(&chip->dev);
    265
    266	return __crb_relinquish_locality(&chip->dev, priv, loc);
    267}
    268
    269static u8 crb_status(struct tpm_chip *chip)
    270{
    271	struct crb_priv *priv = dev_get_drvdata(&chip->dev);
    272	u8 sts = 0;
    273
    274	if ((ioread32(&priv->regs_t->ctrl_start) & CRB_START_INVOKE) !=
    275	    CRB_START_INVOKE)
    276		sts |= CRB_DRV_STS_COMPLETE;
    277
    278	return sts;
    279}
    280
    281static int crb_recv(struct tpm_chip *chip, u8 *buf, size_t count)
    282{
    283	struct crb_priv *priv = dev_get_drvdata(&chip->dev);
    284	unsigned int expected;
    285
    286	/* A sanity check that the upper layer wants to get at least the header
    287	 * as that is the minimum size for any TPM response.
    288	 */
    289	if (count < TPM_HEADER_SIZE)
    290		return -EIO;
    291
    292	/* If this bit is set, according to the spec, the TPM is in
    293	 * unrecoverable condition.
    294	 */
    295	if (ioread32(&priv->regs_t->ctrl_sts) & CRB_CTRL_STS_ERROR)
    296		return -EIO;
    297
    298	/* Read the first 8 bytes in order to get the length of the response.
    299	 * We read exactly a quad word in order to make sure that the remaining
    300	 * reads will be aligned.
    301	 */
    302	memcpy_fromio(buf, priv->rsp, 8);
    303
    304	expected = be32_to_cpup((__be32 *)&buf[2]);
    305	if (expected > count || expected < TPM_HEADER_SIZE)
    306		return -EIO;
    307
    308	memcpy_fromio(&buf[8], &priv->rsp[8], expected - 8);
    309
    310	return expected;
    311}
    312
    313static int crb_do_acpi_start(struct tpm_chip *chip)
    314{
    315	union acpi_object *obj;
    316	int rc;
    317
    318	obj = acpi_evaluate_dsm(chip->acpi_dev_handle,
    319				&crb_acpi_start_guid,
    320				CRB_ACPI_START_REVISION_ID,
    321				CRB_ACPI_START_INDEX,
    322				NULL);
    323	if (!obj)
    324		return -ENXIO;
    325	rc = obj->integer.value == 0 ? 0 : -ENXIO;
    326	ACPI_FREE(obj);
    327	return rc;
    328}
    329
    330#ifdef CONFIG_ARM64
    331/*
    332 * This is a TPM Command Response Buffer start method that invokes a
    333 * Secure Monitor Call to requrest the firmware to execute or cancel
    334 * a TPM 2.0 command.
    335 */
    336static int tpm_crb_smc_start(struct device *dev, unsigned long func_id)
    337{
    338	struct arm_smccc_res res;
    339
    340	arm_smccc_smc(func_id, 0, 0, 0, 0, 0, 0, 0, &res);
    341	if (res.a0 != 0) {
    342		dev_err(dev,
    343			FW_BUG "tpm_crb_smc_start() returns res.a0 = 0x%lx\n",
    344			res.a0);
    345		return -EIO;
    346	}
    347
    348	return 0;
    349}
    350#else
    351static int tpm_crb_smc_start(struct device *dev, unsigned long func_id)
    352{
    353	dev_err(dev, FW_BUG "tpm_crb: incorrect start method\n");
    354	return -EINVAL;
    355}
    356#endif
    357
    358static int crb_send(struct tpm_chip *chip, u8 *buf, size_t len)
    359{
    360	struct crb_priv *priv = dev_get_drvdata(&chip->dev);
    361	int rc = 0;
    362
    363	/* Zero the cancel register so that the next command will not get
    364	 * canceled.
    365	 */
    366	iowrite32(0, &priv->regs_t->ctrl_cancel);
    367
    368	if (len > priv->cmd_size) {
    369		dev_err(&chip->dev, "invalid command count value %zd %d\n",
    370			len, priv->cmd_size);
    371		return -E2BIG;
    372	}
    373
    374	memcpy_toio(priv->cmd, buf, len);
    375
    376	/* Make sure that cmd is populated before issuing start. */
    377	wmb();
    378
    379	/* The reason for the extra quirk is that the PTT in 4th Gen Core CPUs
    380	 * report only ACPI start but in practice seems to require both
    381	 * CRB start, hence invoking CRB start method if hid == MSFT0101.
    382	 */
    383	if ((priv->sm == ACPI_TPM2_COMMAND_BUFFER) ||
    384	    (priv->sm == ACPI_TPM2_MEMORY_MAPPED) ||
    385	    (!strcmp(priv->hid, "MSFT0101")))
    386		iowrite32(CRB_START_INVOKE, &priv->regs_t->ctrl_start);
    387
    388	if ((priv->sm == ACPI_TPM2_START_METHOD) ||
    389	    (priv->sm == ACPI_TPM2_COMMAND_BUFFER_WITH_START_METHOD))
    390		rc = crb_do_acpi_start(chip);
    391
    392	if (priv->sm == ACPI_TPM2_COMMAND_BUFFER_WITH_ARM_SMC) {
    393		iowrite32(CRB_START_INVOKE, &priv->regs_t->ctrl_start);
    394		rc = tpm_crb_smc_start(&chip->dev, priv->smc_func_id);
    395	}
    396
    397	return rc;
    398}
    399
    400static void crb_cancel(struct tpm_chip *chip)
    401{
    402	struct crb_priv *priv = dev_get_drvdata(&chip->dev);
    403
    404	iowrite32(CRB_CANCEL_INVOKE, &priv->regs_t->ctrl_cancel);
    405
    406	if (((priv->sm == ACPI_TPM2_START_METHOD) ||
    407	    (priv->sm == ACPI_TPM2_COMMAND_BUFFER_WITH_START_METHOD)) &&
    408	     crb_do_acpi_start(chip))
    409		dev_err(&chip->dev, "ACPI Start failed\n");
    410}
    411
    412static bool crb_req_canceled(struct tpm_chip *chip, u8 status)
    413{
    414	struct crb_priv *priv = dev_get_drvdata(&chip->dev);
    415	u32 cancel = ioread32(&priv->regs_t->ctrl_cancel);
    416
    417	return (cancel & CRB_CANCEL_INVOKE) == CRB_CANCEL_INVOKE;
    418}
    419
    420static const struct tpm_class_ops tpm_crb = {
    421	.flags = TPM_OPS_AUTO_STARTUP,
    422	.status = crb_status,
    423	.recv = crb_recv,
    424	.send = crb_send,
    425	.cancel = crb_cancel,
    426	.req_canceled = crb_req_canceled,
    427	.go_idle  = crb_go_idle,
    428	.cmd_ready = crb_cmd_ready,
    429	.request_locality = crb_request_locality,
    430	.relinquish_locality = crb_relinquish_locality,
    431	.req_complete_mask = CRB_DRV_STS_COMPLETE,
    432	.req_complete_val = CRB_DRV_STS_COMPLETE,
    433};
    434
    435static int crb_check_resource(struct acpi_resource *ares, void *data)
    436{
    437	struct resource *iores_array = data;
    438	struct resource_win win;
    439	struct resource *res = &(win.res);
    440	int i;
    441
    442	if (acpi_dev_resource_memory(ares, res) ||
    443	    acpi_dev_resource_address_space(ares, &win)) {
    444		for (i = 0; i < TPM_CRB_MAX_RESOURCES + 1; ++i) {
    445			if (resource_type(iores_array + i) != IORESOURCE_MEM) {
    446				iores_array[i] = *res;
    447				iores_array[i].name = NULL;
    448				break;
    449			}
    450		}
    451	}
    452
    453	return 1;
    454}
    455
    456static void __iomem *crb_map_res(struct device *dev, struct resource *iores,
    457				 void __iomem **iobase_ptr, u64 start, u32 size)
    458{
    459	struct resource new_res = {
    460		.start	= start,
    461		.end	= start + size - 1,
    462		.flags	= IORESOURCE_MEM,
    463	};
    464
    465	/* Detect a 64 bit address on a 32 bit system */
    466	if (start != new_res.start)
    467		return IOMEM_ERR_PTR(-EINVAL);
    468
    469	if (!iores)
    470		return devm_ioremap_resource(dev, &new_res);
    471
    472	if (!*iobase_ptr) {
    473		*iobase_ptr = devm_ioremap_resource(dev, iores);
    474		if (IS_ERR(*iobase_ptr))
    475			return *iobase_ptr;
    476	}
    477
    478	return *iobase_ptr + (new_res.start - iores->start);
    479}
    480
    481/*
    482 * Work around broken BIOSs that return inconsistent values from the ACPI
    483 * region vs the registers. Trust the ACPI region. Such broken systems
    484 * probably cannot send large TPM commands since the buffer will be truncated.
    485 */
    486static u64 crb_fixup_cmd_size(struct device *dev, struct resource *io_res,
    487			      u64 start, u64 size)
    488{
    489	if (io_res->start > start || io_res->end < start)
    490		return size;
    491
    492	if (start + size - 1 <= io_res->end)
    493		return size;
    494
    495	dev_err(dev,
    496		FW_BUG "ACPI region does not cover the entire command/response buffer. %pr vs %llx %llx\n",
    497		io_res, start, size);
    498
    499	return io_res->end - start + 1;
    500}
    501
    502static int crb_map_io(struct acpi_device *device, struct crb_priv *priv,
    503		      struct acpi_table_tpm2 *buf)
    504{
    505	struct list_head acpi_resource_list;
    506	struct resource iores_array[TPM_CRB_MAX_RESOURCES + 1] = { {0} };
    507	void __iomem *iobase_array[TPM_CRB_MAX_RESOURCES] = {NULL};
    508	struct device *dev = &device->dev;
    509	struct resource *iores;
    510	void __iomem **iobase_ptr;
    511	int i;
    512	u32 pa_high, pa_low;
    513	u64 cmd_pa;
    514	u32 cmd_size;
    515	__le64 __rsp_pa;
    516	u64 rsp_pa;
    517	u32 rsp_size;
    518	int ret;
    519
    520	INIT_LIST_HEAD(&acpi_resource_list);
    521	ret = acpi_dev_get_resources(device, &acpi_resource_list,
    522				     crb_check_resource, iores_array);
    523	if (ret < 0)
    524		return ret;
    525	acpi_dev_free_resource_list(&acpi_resource_list);
    526
    527	if (resource_type(iores_array) != IORESOURCE_MEM) {
    528		dev_err(dev, FW_BUG "TPM2 ACPI table does not define a memory resource\n");
    529		return -EINVAL;
    530	} else if (resource_type(iores_array + TPM_CRB_MAX_RESOURCES) ==
    531		IORESOURCE_MEM) {
    532		dev_warn(dev, "TPM2 ACPI table defines too many memory resources\n");
    533		memset(iores_array + TPM_CRB_MAX_RESOURCES,
    534		       0, sizeof(*iores_array));
    535		iores_array[TPM_CRB_MAX_RESOURCES].flags = 0;
    536	}
    537
    538	iores = NULL;
    539	iobase_ptr = NULL;
    540	for (i = 0; resource_type(iores_array + i) == IORESOURCE_MEM; ++i) {
    541		if (buf->control_address >= iores_array[i].start &&
    542		    buf->control_address + sizeof(struct crb_regs_tail) - 1 <=
    543		    iores_array[i].end) {
    544			iores = iores_array + i;
    545			iobase_ptr = iobase_array + i;
    546			break;
    547		}
    548	}
    549
    550	priv->regs_t = crb_map_res(dev, iores, iobase_ptr, buf->control_address,
    551				   sizeof(struct crb_regs_tail));
    552
    553	if (IS_ERR(priv->regs_t))
    554		return PTR_ERR(priv->regs_t);
    555
    556	/* The ACPI IO region starts at the head area and continues to include
    557	 * the control area, as one nice sane region except for some older
    558	 * stuff that puts the control area outside the ACPI IO region.
    559	 */
    560	if ((priv->sm == ACPI_TPM2_COMMAND_BUFFER) ||
    561	    (priv->sm == ACPI_TPM2_MEMORY_MAPPED)) {
    562		if (iores &&
    563		    buf->control_address == iores->start +
    564		    sizeof(*priv->regs_h))
    565			priv->regs_h = *iobase_ptr;
    566		else
    567			dev_warn(dev, FW_BUG "Bad ACPI memory layout");
    568	}
    569
    570	ret = __crb_request_locality(dev, priv, 0);
    571	if (ret)
    572		return ret;
    573
    574	/*
    575	 * PTT HW bug w/a: wake up the device to access
    576	 * possibly not retained registers.
    577	 */
    578	ret = __crb_cmd_ready(dev, priv);
    579	if (ret)
    580		goto out_relinquish_locality;
    581
    582	pa_high = ioread32(&priv->regs_t->ctrl_cmd_pa_high);
    583	pa_low  = ioread32(&priv->regs_t->ctrl_cmd_pa_low);
    584	cmd_pa = ((u64)pa_high << 32) | pa_low;
    585	cmd_size = ioread32(&priv->regs_t->ctrl_cmd_size);
    586
    587	iores = NULL;
    588	iobase_ptr = NULL;
    589	for (i = 0; iores_array[i].end; ++i) {
    590		if (cmd_pa >= iores_array[i].start &&
    591		    cmd_pa <= iores_array[i].end) {
    592			iores = iores_array + i;
    593			iobase_ptr = iobase_array + i;
    594			break;
    595		}
    596	}
    597
    598	if (iores)
    599		cmd_size = crb_fixup_cmd_size(dev, iores, cmd_pa, cmd_size);
    600
    601	dev_dbg(dev, "cmd_hi = %X cmd_low = %X cmd_size %X\n",
    602		pa_high, pa_low, cmd_size);
    603
    604	priv->cmd = crb_map_res(dev, iores, iobase_ptr,	cmd_pa, cmd_size);
    605	if (IS_ERR(priv->cmd)) {
    606		ret = PTR_ERR(priv->cmd);
    607		goto out;
    608	}
    609
    610	memcpy_fromio(&__rsp_pa, &priv->regs_t->ctrl_rsp_pa, 8);
    611	rsp_pa = le64_to_cpu(__rsp_pa);
    612	rsp_size = ioread32(&priv->regs_t->ctrl_rsp_size);
    613
    614	iores = NULL;
    615	iobase_ptr = NULL;
    616	for (i = 0; resource_type(iores_array + i) == IORESOURCE_MEM; ++i) {
    617		if (rsp_pa >= iores_array[i].start &&
    618		    rsp_pa <= iores_array[i].end) {
    619			iores = iores_array + i;
    620			iobase_ptr = iobase_array + i;
    621			break;
    622		}
    623	}
    624
    625	if (iores)
    626		rsp_size = crb_fixup_cmd_size(dev, iores, rsp_pa, rsp_size);
    627
    628	if (cmd_pa != rsp_pa) {
    629		priv->rsp = crb_map_res(dev, iores, iobase_ptr,
    630					rsp_pa, rsp_size);
    631		ret = PTR_ERR_OR_ZERO(priv->rsp);
    632		goto out;
    633	}
    634
    635	/* According to the PTP specification, overlapping command and response
    636	 * buffer sizes must be identical.
    637	 */
    638	if (cmd_size != rsp_size) {
    639		dev_err(dev, FW_BUG "overlapping command and response buffer sizes are not identical");
    640		ret = -EINVAL;
    641		goto out;
    642	}
    643
    644	priv->rsp = priv->cmd;
    645
    646out:
    647	if (!ret)
    648		priv->cmd_size = cmd_size;
    649
    650	__crb_go_idle(dev, priv);
    651
    652out_relinquish_locality:
    653
    654	__crb_relinquish_locality(dev, priv, 0);
    655
    656	return ret;
    657}
    658
    659static int crb_acpi_add(struct acpi_device *device)
    660{
    661	struct acpi_table_tpm2 *buf;
    662	struct crb_priv *priv;
    663	struct tpm_chip *chip;
    664	struct device *dev = &device->dev;
    665	struct tpm2_crb_smc *crb_smc;
    666	acpi_status status;
    667	u32 sm;
    668	int rc;
    669
    670	status = acpi_get_table(ACPI_SIG_TPM2, 1,
    671				(struct acpi_table_header **) &buf);
    672	if (ACPI_FAILURE(status) || buf->header.length < sizeof(*buf)) {
    673		dev_err(dev, FW_BUG "failed to get TPM2 ACPI table\n");
    674		return -EINVAL;
    675	}
    676
    677	/* Should the FIFO driver handle this? */
    678	sm = buf->start_method;
    679	if (sm == ACPI_TPM2_MEMORY_MAPPED)
    680		return -ENODEV;
    681
    682	priv = devm_kzalloc(dev, sizeof(struct crb_priv), GFP_KERNEL);
    683	if (!priv)
    684		return -ENOMEM;
    685
    686	if (sm == ACPI_TPM2_COMMAND_BUFFER_WITH_ARM_SMC) {
    687		if (buf->header.length < (sizeof(*buf) + sizeof(*crb_smc))) {
    688			dev_err(dev,
    689				FW_BUG "TPM2 ACPI table has wrong size %u for start method type %d\n",
    690				buf->header.length,
    691				ACPI_TPM2_COMMAND_BUFFER_WITH_ARM_SMC);
    692			return -EINVAL;
    693		}
    694		crb_smc = ACPI_ADD_PTR(struct tpm2_crb_smc, buf, sizeof(*buf));
    695		priv->smc_func_id = crb_smc->smc_func_id;
    696	}
    697
    698	priv->sm = sm;
    699	priv->hid = acpi_device_hid(device);
    700
    701	rc = crb_map_io(device, priv, buf);
    702	if (rc)
    703		return rc;
    704
    705	chip = tpmm_chip_alloc(dev, &tpm_crb);
    706	if (IS_ERR(chip))
    707		return PTR_ERR(chip);
    708
    709	dev_set_drvdata(&chip->dev, priv);
    710	chip->acpi_dev_handle = device->handle;
    711	chip->flags = TPM_CHIP_FLAG_TPM2;
    712
    713	return tpm_chip_register(chip);
    714}
    715
    716static int crb_acpi_remove(struct acpi_device *device)
    717{
    718	struct device *dev = &device->dev;
    719	struct tpm_chip *chip = dev_get_drvdata(dev);
    720
    721	tpm_chip_unregister(chip);
    722
    723	return 0;
    724}
    725
    726static const struct dev_pm_ops crb_pm = {
    727	SET_SYSTEM_SLEEP_PM_OPS(tpm_pm_suspend, tpm_pm_resume)
    728};
    729
    730static const struct acpi_device_id crb_device_ids[] = {
    731	{"MSFT0101", 0},
    732	{"", 0},
    733};
    734MODULE_DEVICE_TABLE(acpi, crb_device_ids);
    735
    736static struct acpi_driver crb_acpi_driver = {
    737	.name = "tpm_crb",
    738	.ids = crb_device_ids,
    739	.ops = {
    740		.add = crb_acpi_add,
    741		.remove = crb_acpi_remove,
    742	},
    743	.drv = {
    744		.pm = &crb_pm,
    745	},
    746};
    747
    748module_acpi_driver(crb_acpi_driver);
    749MODULE_AUTHOR("Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>");
    750MODULE_DESCRIPTION("TPM2 Driver");
    751MODULE_VERSION("0.1");
    752MODULE_LICENSE("GPL");