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|
/******************************************************************************
* 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 {
int irq;
unsigned int intrs;
wait_queue_head_t read_queue;
};
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.parent);
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.parent);
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->flags & TPM_CHIP_FLAG_IRQ) && queue) {
s32 rc;
struct priv_data *priv = chip->vendor.priv;
unsigned int cur_intrs = priv->intrs;
enable_irq(priv->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
|