/******************************************************************************
* Nuvoton TPM I2C Device Driver Interface for WPCT301/NPCT501,
* based on the TCG TPM Interface Spec version 1.2.
* Specifications at www.trustedcomputinggroup.org
*
* Copyright (C) 2011, Nuvoton Technology Corporation.
* Dan Morav <dan.morav@nuvoton.com>
* Copyright (C) 2013, Obsidian Research Corp.
* Jason Gunthorpe <jgunthorpe@obsidianresearch.com>
*
* 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, either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see http://www.gnu.org/licenses/>.
*
* Nuvoton contact information: APC.Support@nuvoton.com
*****************************************************************************/
#include <linux/init.h>
#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/slab.h>
#include <linux/interrupt.h>
#include <linux/wait.h>
#include <linux/i2c.h>
#include "tpm.h"
/* I2C interface offsets */
#define TPM_STS 0x00
#define TPM_BURST_COUNT 0x01
#define TPM_DATA_FIFO_W 0x20
#define TPM_DATA_FIFO_R 0x40
#define TPM_VID_DID_RID 0x60
/* TPM command header size */
#define TPM_HEADER_SIZE 10
#define TPM_RETRY 5
/*
* I2C bus device maximum buffer size w/o counting I2C address or command
* i.e. max size required for I2C write is 34 = addr, command, 32 bytes data
*/
#define TPM_I2C_MAX_BUF_SIZE 32
#define TPM_I2C_RETRY_COUNT 32
#define TPM_I2C_BUS_DELAY 1 /* msec */
#define TPM_I2C_RETRY_DELAY_SHORT 2 /* msec */
#define TPM_I2C_RETRY_DELAY_LONG 10 /* msec */
#define I2C_DRIVER_NAME "tpm_i2c_nuvoton"
struct priv_data {
unsigned int intrs;
};
static s32 i2c_nuvoton_read_buf(struct i2c_client *client, u8 offset, u8 size,
u8 *data)
{
s32 status;
status = i2c_smbus_read_i2c_block_data(client, offset, size, data);
dev_dbg(&client->dev,
"%s(offset=%u size=%u data=%*ph) -> sts=%d\n", __func__,
offset, size, (int)size, data, status);
return status;
}
static s32 i2c_nuvoton_write_buf(struct i2c_client *client, u8 offset, u8 size,
u8 *data)
{
s32 status;
status = i2c_smbus_write_i2c_block_data(client, offset, size, data);
dev_dbg(&client->dev,
"%s(offset=%u size=%u data=%*ph) -> sts=%d\n", __func__,
offset, size, (int)size, data, status);
return status;
}
#define TPM_STS_VALID 0x80
#define TPM_STS_COMMAND_READY 0x40
#define TPM_STS_GO 0x20
#define TPM_STS_DATA_AVAIL 0x10
#define TPM_STS_EXPECT 0x08
#define TPM_STS_RESPONSE_RETRY 0x02
#define TPM_STS_ERR_VAL 0x07 /* bit2...bit0 reads always 0 */
#define TPM_I2C_SHORT_TIMEOUT 750 /* ms */
#define TPM_I2C_LONG_TIMEOUT 2000 /* 2 sec */
/* read TPM_STS register */
static u8 i2c_nuvoton_read_status(struct tpm_chip *chip)
{
struct i2c_client *client = to_i2c_client(chip->pdev);
s32 status;
u8 data;
status = i2c_nuvoton_read_buf(client, TPM_STS, 1, &data);
if (status <= 0) {
dev_err(chip->pdev, "%s() error return %d\n", __func__,
status);
data = TPM_STS_ERR_VAL;
}
return data;
}
/* write byte to TPM_STS register */
static s32 i2c_nuvoton_write_status(struct i2c_client *client, u8 data)
{
s32 status;
int i;
/* this causes the current command to be aborted */
for (i = 0, status = -1; i < TPM_I2C_RETRY_COUNT && status < 0; i++) {
status = i2c_nuvoton_write_buf(client, TPM_STS, 1, &data);
msleep(TPM_I2C_BUS_DELAY);
}
return status;
}
/* write commandReady to TPM_STS register */
static void i2c_nuvoton_ready(struct tpm_chip *chip)
{
struct i2c_client *client = to_i2c_client(chip->pdev);
s32 status;
/* this causes the current command to be aborted */
status = i2c_nuvoton_write_status(client, TPM_STS_COMMAND_READY);
if (status < 0)
dev_err(chip->pdev,
"%s() fail to write TPM_STS.commandReady\n", __func__);
}
/* read burstCount field from TPM_STS register
* return -1 on fail to read */
static int i2c_nuvoton_get_burstcount(struct i2c_client *client,
struct tpm_chip *chip)
{
unsigned long stop = jiffies + chip->vendor.timeout_d;
s32 status;
int burst_count = -1;
u8 data;
/* wait for burstcount to be non-zero */
do {
/* in I2C burstCount is 1 byte */
status = i2c_nuvoton_read_buf(client, TPM_BURST_COUNT, 1,
&data);
if (status > 0 && data > 0) {
burst_count = min_t(u8, TPM_I2C_MAX_BUF_SIZE, data);
break;
}
msleep(TPM_I2C_BUS_DELAY);
} while (time_before(jiffies, stop));
return burst_count;
}
/*
* WPCT301/NPCT501 SINT# supports only dataAvail
* any call to this function which is not waiting for dataAvail will
* set queue to NULL to avoid waiting for interrupt
*/
static bool i2c_nuvoton_check_status(struct tpm_chip *chip, u8 mask, u8 value)
{
u8 status = i2c_nuvoton_read_status(chip);
return (status != TPM_STS_ERR_VAL) && ((status & mask) == value);
}
static int i2c_nuvoton_wait_for_stat(struct tpm_chip *chip, u8 mask, u8 value,
u32 timeout, wait_queue_head_t *queue)
{
if (chip->vendor.irq && queue) {
s32 rc;
struct priv_data *priv = chip->vendor.priv;
unsigned int cur_intrs = priv->intrs;
enable_irq(chip->vendor.irq);
rc = wait_event_interruptible_timeout(*queue,
cur_intrs != priv->intrs,
timeout);
if (rc > 0)
return 0;
/* At this point we know that the SINT pin is asserted, so we
* do not need to do i2c_nuvoton_check_status */
} else {
unsigned long ten_msec, stop;
bool status_valid;
/* check current status */
status_valid = i2c_nuvoton_check_status(chip, mask, value);
if (status_valid)
return 0;
/* use polling to wait for the event */
ten_msec = jiffies + msecs_to_jiffies(TPM_I2C_RETRY_DELAY_LONG);
stop = jiffies + timeout;
do {
if (time_before(jiffies, ten_msec))
msleep(TPM_I2C_RETRY_DELAY_SHORT);
else
msleep(TPM_I2C_RETRY_DELAY_LONG);
status_valid = i2c_nuvoton_check_status(chip, mask,
value);
if (status_valid)
return 0;
} while (time_before(jiffies, stop));
}
dev_err(chip->pdev, "%s(%02x, %02x) -> timeout\n", __func__, mask,
value);
return -ETIMEDOUT;
}
/* wait for dataAvail field to be set in the TPM_STS register */
static int i2c_nuvoton_wait_for_data_avail(struct tpm_chip *chip, u32 timeout,
wait_queue_head_t *queue)
{
return i2c_nuvoton_wait_for_stat(chip,
TPM_STS_DATA_AVAIL | TPM_STS_VALID,
TPM_STS_DATA_AVAIL | TPM_STS_VALID,
timeout, queue);
}
/* Read @count bytes into @buf from TPM_RD_FIFO register */
static int i2c_nuvoton_recv_data(struct i2c_client *client,
struct tpm_chip *chip, u8 *buf, size_t count)
{
s32 rc;
int burst_count, bytes2read, size = 0;
while (size < count &&
i2c_nuvoton_wait_for_data_avail(chip,
chip->vendor.timeout_c,
&chip->vendor.read_queue) == 0) {
burst_count = i2c_nuvoton_get_burstcount(client, chip);
if (burst_count < 0) {
dev_err(chip->pdev,
"%s() fail to read burstCount=%d\n", __func__,
burst_count);
return -EIO;
}
bytes2read = min_t(size_t, burst_count, count - size);
rc = i2c_nuvoton_read_buf(client, TPM_DATA_FIFO_R,
bytes2read, &buf[size]);
if (rc < 0) {
dev_err(chip->pdev,
"%s() fail on i2c_nuvoton_read_buf()=%d\n",
__func__, rc);
return -EIO;
}
dev_dbg(chip->pdev, "%s(%d):", __func__, bytes2read);
size += bytes2read;
}
return size;
}
/* Read TPM command results */
static int i2c_nuvoton_recv(struct tpm_chip *chip, u8 *buf, size_t count)
{
struct device *dev = chip->pdev;
struct i2c_client *client = to_i2c_client(dev);
s32 rc;
int expected, status, burst_count, retries, size = 0;
if (count < TPM_HEADER_SIZE) {
i2c_nuvoton_ready(chip); /* return to idle */
dev_err(dev, "%s() count < header size\n", __func__);
return -EIO;
}
for (retries = 0; retries < TPM_RETRY; retries++) {
if (retries > 0) {
/* if this is not the first trial, set responseRetry */
i2c_nuvoton_write_status(client,
TPM_STS_RESPONSE_RETRY);
}
/*
* read first available (> 10 bytes), including:
* tag, paramsize, and result
*/
status = i2c_nuvoton_wait_for_data_avail(
chip, chip->vendor.timeout_c, &chip->vendor.read_queue);
if (status != 0) {
dev_err(dev, "%s() timeout on dataAvail\n", __func__);
size = -ETIMEDOUT;
continue;
}
burst_count = i2c_nuvoton_get_burstcount(client, chip);
if (burst_count < 0) {
dev_err(dev, "%s() fail to get burstCount\n", __func__);
size = -EIO;
continue;
}
size = i2c_nuvoton_recv_data(client, chip, buf,
burst_count);
if (size < TPM_HEADER_SIZE) {
dev_err(dev, "%s() fail to read header\n", __func__);
size = -EIO;
continue;
}
/*
* convert number of expected bytes field from big endian 32 bit
* to machine native
*/
expected = be32_to_cpu(*(__be32 *) (buf + 2));
if (expected > count) {
dev_err(dev, "%s() expected > count\n", __func__);
size = -EIO;
continue;
}
rc = i2c_nuvoton_recv_data(client, chip, &buf[size],
expected - size);
size += rc;
if (rc < 0 || size < expected) {
dev_err(dev, "%s() fail to read remainder of result\n",
__func__);
size = -EIO;
continue;
}
if (i2c_nuvoton_wait_for_stat(
chip, TPM_STS_VALID | TPM_STS_DATA_AVAIL,
TPM_STS_VALID, chip->vendor.timeout_c,
NULL)) {
dev_err(dev, "%s() error left over data\n", __func__);
size = -ETIMEDOUT;
continue;
}
break;
}
i2c_nuvoton_ready(chip);
dev_dbg(chip->pdev, "%s() -> %d\n", __func__, size);
return size;
}
/*
* Send TPM command.
*
* If interrupts are used (signaled by an irq set in the vendor structure)
* tpm.c can skip polling for the data to be available as the interrupt is
* waited for here
*/
static int i2c_nuvoton_send(struct tpm_chip *chip, u8 *buf, size_t len)
{
struct device *dev = chip->pdev;
struct i2c_client *client = to_i2c_client(dev);
u32 ordinal;
size_t count = 0;
int burst_count, bytes2write, retries, rc = -EIO;
for (retries = 0; retries < TPM_RETRY; retries++) {
i2c_nuvoton_ready(chip);
if (i2c_nuvoton_wait_for_stat(chip, TPM_STS_COMMAND_READY,
TPM_STS_COMMAND_READY,
chip->vendor.timeout_b, NULL)) {
dev_err(dev, "%s() timeout on commandReady\n",
__func__);
rc = -EIO;
continue;
}
rc = 0;
while (count < len - 1) {
burst_count = i2c_nuvoton_get_burstcount(client,
chip);
if (burst_count < 0) {
dev_err(dev, "%s() fail get burstCount\n",
__func__);
rc = -EIO;
break;
}
bytes2write = min_t(size_t, burst_count,
len - 1 - count);
rc = i2c_nuvoton_write_buf(client, TPM_DATA_FIFO_W,
bytes2write, &buf[count]);
if (rc < 0) {
dev_err(dev, "%s() fail i2cWriteBuf\n",
__func__);
break;
}
dev_dbg(dev, "%s(%d):", __func__, bytes2write);
count += bytes2write;
rc = i2c_nuvoton_wait_for_stat(chip,
TPM_STS_VALID |
TPM_STS_EXPECT,
TPM_STS_VALID |
TPM_STS_EXPECT,
chip->vendor.timeout_c,
NULL);
if (rc < 0) {
dev_err(dev, "%s() timeout on Expect\n",
__func__);
rc = -ETIMEDOUT;
break;
}
}
if (rc < 0)
continue;
/* write last byte */
rc = i2c_nuvoton_write_buf(client, TPM_DATA_FIFO_W, 1,
&buf[count]);
if (rc < 0) {
dev_err(dev, "%s() fail to write last byte\n",
__func__);
rc = -EIO;
continue;
}
dev_dbg(dev, "%s(last): %02x", __func__, buf[count]);
rc = i2c_nuvoton_wait_for_stat(chip,
TPM_STS_VALID | TPM_STS_EXPECT,
TPM_STS_VALID,
chip->vendor.timeout_c, NULL);
if (rc) {
dev_err(dev, "%s() timeout on Expect to clear\n",
__func__);
rc = -ETIMEDOUT;
continue;
}
break;
}
if (rc < 0) {
/* retries == TPM_RETRY */
i2c_nuvoton_ready(chip);
return rc;
}
/* execute the TPM command */
rc = i2c_nuvoton_write_status(client, TPM_STS_GO);
if (rc < 0) {
dev_err(dev, "%s() fail to write Go\n", __func__);
i2c_nuvoton_ready(chip);
return rc;
}
ordinal = be32_to_cpu(*((__be32 *) (buf + 6)));
rc = i2c_nuvoton_wait_for_data_avail(chip,
tpm_calc_ordinal_duration(chip,
ordinal),
&chip->vendor.read_queue);
if (rc) {
dev_err(dev, "%s() timeout command duration\n", __func__);
i2c_nuvoton_ready(chip);
return rc;
}
dev_dbg(dev, "%s() -> %zd\n", __func__, len);
return len;
}
static bool i2c_nuvoton_req_canceled(struct tpm_chip *chip, u8 status)
{
return (status == TPM_STS_COMMAND_READY);
}
static const struct tpm_class_ops tpm_i2c = {
.status = i2c_nuvoton_read_status,
.recv = i2c_nuvoton_recv,
.send = i2c_nuvoton_send,
.cancel = i2c_nuvoton_ready,
.req_complete_mask = TPM_STS_DATA_AVAIL | TPM_STS_VALID,
.req_complete_val = TPM_STS_DATA_AVAIL | TPM_STS_VALID,
.req_canceled = i2c_nuvoton_req_canceled,
};
/* The only purpose for the handler is to signal to any waiting threads that
* the interrupt is currently being asserted. The driver does not do any
* processing triggered by interrupts, and the chip provides no way to mask at
* the source (plus that would be slow over I2C). Run the IRQ as a one-shot,
* this means it cannot be shared. */
static irqreturn_t i2c_nuvoton_int_handler(int dummy, void *dev_id)
{
struct tpm_chip *chip = dev_id;
struct priv_data *priv = chip->vendor.priv;
priv->intrs++;
wake_up(&chip->vendor.read_queue);
disable_irq_nosync(chip->vendor.irq);
return IRQ_HANDLED;
}
static int get_vid(struct i2c_client *client, u32 *res)
{
static const u8 vid_did_rid_value[] = { 0x50, 0x10, 0xfe };
u32 temp;
s32 rc;
if (!i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_BYTE_DATA))
return -ENODEV;
rc = i2c_nuvoton_read_buf(client, TPM_VID_DID_RID, 4, (u8 *)&temp);
if (rc < 0)
return rc;
/* check WPCT301 values - ignore RID */
if (memcmp(&temp, vid_did_rid_value, sizeof(vid_did_rid_value))) {
/*
* f/w rev 2.81 has an issue where the VID_DID_RID is not
* reporting the right value. so give it another chance at
* offset 0x20 (FIFO_W).
*/
rc = i2c_nuvoton_read_buf(client, TPM_DATA_FIFO_W, 4,
(u8 *) (&temp));
if (rc < 0)
return rc;
/* check WPCT301 values - ignore RID */
if (memcmp(&temp, vid_did_rid_value,
sizeof(vid_did_rid_value)))
return -ENODEV;
}
*res = temp;
return 0;
}
static int i2c_nuvoton_probe(struct i2c_client *client,
const struct i2c_device_id *id)
{
int rc;
struct tpm_chip *chip;
struct device *dev = &client->dev;
u32 vid = 0;
rc = get_vid(client, &vid);
if (rc)
return rc;
dev_info(dev, "VID: %04X DID: %02X RID: %02X\n", (u16) vid,
(u8) (vid >> 16), (u8) (vid >> 24));
chip = tpmm_chip_alloc(dev, &tpm_i2c);
if (IS_ERR(chip))
return PTR_ERR(chip);
chip->vendor.priv = devm_kzalloc(dev, sizeof(struct priv_data),
GFP_KERNEL);
if (!chip->vendor.priv)
return -ENOMEM;
init_waitqueue_head(&chip->vendor.read_queue);
init_waitqueue_head(&chip->vendor.int_queue);
/* Default timeouts */
chip->vendor.timeout_a = msecs_to_jiffies(TPM_I2C_SHORT_TIMEOUT);
chip->vendor.timeout_b = msecs_to_jiffies(TPM_I2C_LONG_TIMEOUT);
chip->vendor.timeout_c = msecs_to_jiffies(TPM_I2C_SHORT_TIMEOUT);
chip->vendor.timeout_d = msecs_to_jiffies(TPM_I2C_SHORT_TIMEOUT);
/*
* I2C intfcaps (interrupt capabilitieis) in the chip are hard coded to:
* TPM_INTF_INT_LEVEL_LOW | TPM_INTF_DATA_AVAIL_INT
* The IRQ should be set in the i2c_board_info (which is done
* automatically in of_i2c_register_devices, for device tree users */
chip->vendor.irq = client->irq;
if (chip->vendor.irq) {
dev_dbg(dev, "%s() chip-vendor.irq\n", __func__);
rc = devm_request_irq(dev, chip->vendor.irq,
i2c_nuvoton_int_handler,
IRQF_TRIGGER_LOW,
chip->devname,
chip);
if (rc) {
dev_err(dev, "%s() Unable to request irq: %d for use\n",
__func__, chip->vendor.irq);
chip->vendor.irq = 0;
} else {
/* Clear any pending interrupt */
i2c_nuvoton_ready(chip);
/* - wait for TPM_STS==0xA0 (stsValid, commandReady) */
rc = i2c_nuvoton_wait_for_stat(chip,
TPM_STS_COMMAND_READY,
TPM_STS_COMMAND_READY,
chip->vendor.timeout_b,
NULL);
if (rc == 0) {
/*
* TIS is in ready state
* write dummy byte to enter reception state
* TPM_DATA_FIFO_W <- rc (0)
*/
rc = i2c_nuvoton_write_buf(client,
TPM_DATA_FIFO_W,
1, (u8 *) (&rc));
if (rc < 0)
return rc;
/* TPM_STS <- 0x40 (commandReady) */
i2c_nuvoton_ready(chip);
} else {
/*
* timeout_b reached - command was
* aborted. TIS should now be in idle state -
* only TPM_STS_VALID should be set
*/
if (i2c_nuvoton_read_status(chip) !=
TPM_STS_VALID)
return -EIO;
}
}
}
if (tpm_get_timeouts(chip))
return -ENODEV;
if (tpm_do_selftest(chip))
return -ENODEV;
return tpm_chip_register(chip);
}
static int i2c_nuvoton_remove(struct i2c_client *client)
{
struct device *dev = &(client->dev);
struct tpm_chip *chip = dev_get_drvdata(dev);
tpm_chip_unregister(chip);
return 0;
}
static const struct i2c_device_id i2c_nuvoton_id[] = {
{I2C_DRIVER_NAME, 0},
{}
};
MODULE_DEVICE_TABLE(i2c, i2c_nuvoton_id);
#ifdef CONFIG_OF
static const struct of_device_id i2c_nuvoton_of_match[] = {
{.compatible = "nuvoton,npct501"},
{.compatible = "winbond,wpct301"},
{},
};
MODULE_DEVICE_TABLE(of, i2c_nuvoton_of_match);
#endif
static SIMPLE_DEV_PM_OPS(i2c_nuvoton_pm_ops, tpm_pm_suspend, tpm_pm_resume);
static struct i2c_driver i2c_nuvoton_driver = {
.id_table = i2c_nuvoton_id,
.probe = i2c_nuvoton_probe,
.remove = i2c_nuvoton_remove,
.driver = {
.name = I2C_DRIVER_NAME,
.pm = &i2c_nuvoton_pm_ops,
.of_match_table = of_match_ptr(i2c_nuvoton_of_match),
},
};
module_i2c_driver(i2c_nuvoton_driver);
MODULE_AUTHOR("Dan Morav (dan.morav@nuvoton.com)");
MODULE_DESCRIPTION("Nuvoton TPM I2C Driver");
MODULE_LICENSE("GPL");
