diff options
Diffstat (limited to 'drivers/char/tpm/tpm_i2c_nuvoton.c')
| -rw-r--r-- | drivers/char/tpm/tpm_i2c_nuvoton.c | 669 |
1 files changed, 669 insertions, 0 deletions
diff --git a/drivers/char/tpm/tpm_i2c_nuvoton.c b/drivers/char/tpm/tpm_i2c_nuvoton.c new file mode 100644 index 00000000000..7b158efd49f --- /dev/null +++ b/drivers/char/tpm/tpm_i2c_nuvoton.c @@ -0,0 +1,669 @@ +/****************************************************************************** + * 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->dev); + s32 status; + u8 data; + + status = i2c_nuvoton_read_buf(client, TPM_STS, 1, &data); + if (status <= 0) { + dev_err(chip->dev, "%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->dev); + 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->dev, + "%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->dev, "%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->dev, + "%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->dev, + "%s() fail on i2c_nuvoton_read_buf()=%d\n", + __func__, rc); + return -EIO; + } + dev_dbg(chip->dev, "%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->dev; + 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->dev, "%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->dev; + 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 = tpm_register_hardware(dev, &tpm_i2c); + if (!chip) { + dev_err(dev, "%s() error in tpm_register_hardware\n", __func__); + return -ENODEV; + } + + chip->vendor.priv = devm_kzalloc(dev, sizeof(struct priv_data), + GFP_KERNEL); + 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->vendor.miscdev.name, + 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) + goto out_err; + /* 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) { + rc = -EIO; + goto out_err; + } + } + } + } + + if (tpm_get_timeouts(chip)) { + rc = -ENODEV; + goto out_err; + } + + if (tpm_do_selftest(chip)) { + rc = -ENODEV; + goto out_err; + } + + return 0; + +out_err: + tpm_dev_vendor_release(chip); + tpm_remove_hardware(chip->dev); + return rc; +} + +static int i2c_nuvoton_remove(struct i2c_client *client) +{ + struct device *dev = &(client->dev); + struct tpm_chip *chip = dev_get_drvdata(dev); + + if (chip) + tpm_dev_vendor_release(chip); + tpm_remove_hardware(dev); + kfree(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, + .owner = THIS_MODULE, + .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"); |