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tpm/st33zp24/spi: Remove nbr_dummy_bytes variable usage
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nbr_dummy_bytes variable could be easily replaced by phy->latency in
st33zp24_spi_send and st33zp24_spi_recv.

Signed-off-by: Christophe Ricard <[email protected]>
Reviewed-by: Jarkko Sakkinen <[email protected]>
Signed-off-by: Jarkko Sakkinen <[email protected]>
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@cricard13
cricard13 authored and Jarkko Sakkinen committed Jun 25, 2016
1 parent add40d6 commit 604e578
Showing 1 changed file with 72 additions and 112 deletions.
184 changes: 72 additions & 112 deletions drivers/char/tpm/st33zp24/spi.c
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Original file line number Diff line number Diff line change
@@ -1,6 +1,6 @@
/*
* STMicroelectronics TPM SPI Linux driver for TPM ST33ZP24
* Copyright (C) 2009 - 2016 STMicroelectronics
* Copyright (C) 2009 - 2015 STMicroelectronics
*
* 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
Expand All @@ -19,10 +19,8 @@
#include <linux/module.h>
#include <linux/spi/spi.h>
#include <linux/gpio.h>
#include <linux/gpio/consumer.h>
#include <linux/of_irq.h>
#include <linux/of_gpio.h>
#include <linux/acpi.h>
#include <linux/tpm.h>
#include <linux/platform_data/st33zp24.h>

Expand Down Expand Up @@ -68,7 +66,7 @@

struct st33zp24_spi_phy {
struct spi_device *spi_device;

struct spi_transfer spi_xfer;
u8 tx_buf[ST33ZP24_SPI_BUFFER_SIZE];
u8 rx_buf[ST33ZP24_SPI_BUFFER_SIZE];

Expand Down Expand Up @@ -112,77 +110,82 @@ static int st33zp24_status_to_errno(u8 code)
static int st33zp24_spi_send(void *phy_id, u8 tpm_register, u8 *tpm_data,
int tpm_size)
{
u8 data = 0;
int total_length = 0, ret = 0;
struct st33zp24_spi_phy *phy = phy_id;
struct spi_device *dev = phy->spi_device;
struct spi_transfer spi_xfer = {
.tx_buf = phy->tx_buf,
.rx_buf = phy->rx_buf,
};
u8 *tx_buf = (u8 *)phy->spi_xfer.tx_buf;
u8 *rx_buf = phy->spi_xfer.rx_buf;

/* Pre-Header */
phy->tx_buf[total_length++] = TPM_WRITE_DIRECTION | LOCALITY0;
phy->tx_buf[total_length++] = tpm_register;
data = TPM_WRITE_DIRECTION | LOCALITY0;
memcpy(tx_buf + total_length, &data, sizeof(data));
total_length++;
data = tpm_register;
memcpy(tx_buf + total_length, &data, sizeof(data));
total_length++;

if (tpm_size > 0 && tpm_register == TPM_DATA_FIFO) {
phy->tx_buf[total_length++] = tpm_size >> 8;
phy->tx_buf[total_length++] = tpm_size;
tx_buf[total_length++] = tpm_size >> 8;
tx_buf[total_length++] = tpm_size;
}

memcpy(&phy->tx_buf[total_length], tpm_data, tpm_size);
memcpy(&tx_buf[total_length], tpm_data, tpm_size);
total_length += tpm_size;

memset(&phy->tx_buf[total_length], TPM_DUMMY_BYTE, phy->latency);
memset(&tx_buf[total_length], TPM_DUMMY_BYTE, phy->latency);

spi_xfer.len = total_length + phy->latency;
phy->spi_xfer.len = total_length + phy->latency;

ret = spi_sync_transfer(dev, &spi_xfer, 1);
ret = spi_sync_transfer(dev, &phy->spi_xfer, 1);
if (ret == 0)
ret = phy->rx_buf[total_length + phy->latency - 1];
ret = rx_buf[total_length + phy->latency - 1];

return st33zp24_status_to_errno(ret);
} /* st33zp24_spi_send() */

/*
* st33zp24_spi_read8_recv
* read8_recv
* Recv byte from the TIS register according to the ST33ZP24 SPI protocol.
* @param: phy_id, the phy description
* @param: tpm_register, the tpm tis register where the data should be read
* @param: tpm_data, the TPM response
* @param: tpm_size, tpm TPM response size to read.
* @return: should be zero if success else a negative error code.
*/
static int st33zp24_spi_read8_reg(void *phy_id, u8 tpm_register, u8 *tpm_data,
int tpm_size)
static int read8_reg(void *phy_id, u8 tpm_register, u8 *tpm_data, int tpm_size)
{
u8 data = 0;
int total_length = 0, ret;
struct st33zp24_spi_phy *phy = phy_id;
struct spi_device *dev = phy->spi_device;
struct spi_transfer spi_xfer = {
.tx_buf = phy->tx_buf,
.rx_buf = phy->rx_buf,
};
u8 *tx_buf = (u8 *)phy->spi_xfer.tx_buf;
u8 *rx_buf = phy->spi_xfer.rx_buf;

/* Pre-Header */
phy->tx_buf[total_length++] = LOCALITY0;
phy->tx_buf[total_length++] = tpm_register;

memset(&phy->tx_buf[total_length], TPM_DUMMY_BYTE,
data = LOCALITY0;
memcpy(tx_buf + total_length, &data, sizeof(data));
total_length++;
data = tpm_register;
memcpy(tx_buf + total_length, &data, sizeof(data));
total_length++;

memset(&tx_buf[total_length], TPM_DUMMY_BYTE,
phy->latency + tpm_size);

spi_xfer.len = total_length + phy->latency + tpm_size;
phy->spi_xfer.len = total_length + phy->latency + tpm_size;

/* header + status byte + size of the data + status byte */
ret = spi_sync_transfer(dev, &spi_xfer, 1);
ret = spi_sync_transfer(dev, &phy->spi_xfer, 1);
if (tpm_size > 0 && ret == 0) {
ret = phy->rx_buf[total_length + phy->latency - 1];
ret = rx_buf[total_length + phy->latency - 1];

memcpy(tpm_data, phy->rx_buf + total_length + phy->latency,
memcpy(tpm_data, rx_buf + total_length + phy->latency,
tpm_size);
}

return ret;
} /* st33zp24_spi_read8_reg() */
} /* read8_reg() */

/*
* st33zp24_spi_recv
Expand All @@ -198,29 +201,23 @@ static int st33zp24_spi_recv(void *phy_id, u8 tpm_register, u8 *tpm_data,
{
int ret;

ret = st33zp24_spi_read8_reg(phy_id, tpm_register, tpm_data, tpm_size);
ret = read8_reg(phy_id, tpm_register, tpm_data, tpm_size);
if (!st33zp24_status_to_errno(ret))
return tpm_size;
return ret;
} /* st33zp24_spi_recv() */

static int st33zp24_spi_evaluate_latency(void *phy_id)
static int evaluate_latency(void *phy_id)
{
struct st33zp24_spi_phy *phy = phy_id;
int latency = 1, status = 0;
u8 data = 0;

while (!status && latency < MAX_SPI_LATENCY) {
phy->latency = latency;
status = st33zp24_spi_read8_reg(phy_id, TPM_INTF_CAPABILITY,
&data, 1);
status = read8_reg(phy_id, TPM_INTF_CAPABILITY, &data, 1);
latency++;
}
if (status < 0)
return status;
if (latency == MAX_SPI_LATENCY)
return -ENODEV;

return latency - 1;
} /* evaluate_latency() */

Expand All @@ -229,59 +226,24 @@ static const struct st33zp24_phy_ops spi_phy_ops = {
.recv = st33zp24_spi_recv,
};

static int st33zp24_spi_acpi_request_resources(struct spi_device *spi_dev)
#ifdef CONFIG_OF
static int tpm_stm_spi_of_request_resources(struct st33zp24_spi_phy *phy)
{
struct st33zp24_spi_phy *phy = spi_get_drvdata(spi_dev);
const struct acpi_device_id *id;
struct gpio_desc *gpiod_lpcpd;
struct device *dev;

if (!spi_dev)
return -EINVAL;

dev = &spi_dev->dev;

/* Match the struct device against a given list of ACPI IDs */
id = acpi_match_device(dev->driver->acpi_match_table, dev);
if (!id)
return -ENODEV;

/* Get LPCPD GPIO from ACPI */
gpiod_lpcpd = devm_gpiod_get_index(dev, "TPM IO LPCPD", 1,
GPIOD_OUT_HIGH);
if (IS_ERR(gpiod_lpcpd)) {
dev_err(dev, "Failed to retrieve lpcpd-gpios from acpi.\n");
phy->io_lpcpd = -1;
/*
* lpcpd pin is not specified. This is not an issue as
* power management can be also managed by TPM specific
* commands. So leave with a success status code.
*/
return 0;
}

phy->io_lpcpd = desc_to_gpio(gpiod_lpcpd);

return 0;
}

static int st33zp24_spi_of_request_resources(struct spi_device *spi_dev)
{
struct st33zp24_spi_phy *phy = spi_get_drvdata(spi_dev);
struct device_node *pp;
struct spi_device *dev = phy->spi_device;
int gpio;
int ret;

pp = spi_dev->dev.of_node;
pp = dev->dev.of_node;
if (!pp) {
dev_err(&spi_dev->dev, "No platform data\n");
dev_err(&dev->dev, "No platform data\n");
return -ENODEV;
}

/* Get GPIO from device tree */
gpio = of_get_named_gpio(pp, "lpcpd-gpios", 0);
if (gpio < 0) {
dev_err(&spi_dev->dev,
dev_err(&dev->dev,
"Failed to retrieve lpcpd-gpios from dts.\n");
phy->io_lpcpd = -1;
/*
Expand All @@ -292,20 +254,26 @@ static int st33zp24_spi_of_request_resources(struct spi_device *spi_dev)
return 0;
}
/* GPIO request and configuration */
ret = devm_gpio_request_one(&spi_dev->dev, gpio,
ret = devm_gpio_request_one(&dev->dev, gpio,
GPIOF_OUT_INIT_HIGH, "TPM IO LPCPD");
if (ret) {
dev_err(&spi_dev->dev, "Failed to request lpcpd pin\n");
dev_err(&dev->dev, "Failed to request lpcpd pin\n");
return -ENODEV;
}
phy->io_lpcpd = gpio;

return 0;
}
#else
static int tpm_stm_spi_of_request_resources(struct st33zp24_spi_phy *phy)
{
return -ENODEV;
}
#endif

static int st33zp24_spi_request_resources(struct spi_device *dev)
static int tpm_stm_spi_request_resources(struct spi_device *dev,
struct st33zp24_spi_phy *phy)
{
struct st33zp24_spi_phy *phy = spi_get_drvdata(dev);
struct st33zp24_platform_data *pdata;
int ret;

Expand Down Expand Up @@ -333,12 +301,13 @@ static int st33zp24_spi_request_resources(struct spi_device *dev)
}

/*
* st33zp24_spi_probe initialize the TPM device
* tpm_st33_spi_probe initialize the TPM device
* @param: dev, the spi_device drescription (TPM SPI description).
* @return: 0 in case of success.
* or a negative value describing the error.
*/
static int st33zp24_spi_probe(struct spi_device *dev)
static int
tpm_st33_spi_probe(struct spi_device *dev)
{
int ret;
struct st33zp24_platform_data *pdata;
Expand All @@ -357,25 +326,21 @@ static int st33zp24_spi_probe(struct spi_device *dev)
return -ENOMEM;

phy->spi_device = dev;

spi_set_drvdata(dev, phy);

pdata = dev->dev.platform_data;
if (!pdata && dev->dev.of_node) {
ret = st33zp24_spi_of_request_resources(dev);
ret = tpm_stm_spi_of_request_resources(phy);
if (ret)
return ret;
} else if (pdata) {
ret = st33zp24_spi_request_resources(dev);
if (ret)
return ret;
} else if (ACPI_HANDLE(&dev->dev)) {
ret = st33zp24_spi_acpi_request_resources(dev);
ret = tpm_stm_spi_request_resources(dev, phy);
if (ret)
return ret;
}

phy->latency = st33zp24_spi_evaluate_latency(phy);
phy->spi_xfer.tx_buf = phy->tx_buf;
phy->spi_xfer.rx_buf = phy->rx_buf;

phy->latency = evaluate_latency(phy);
if (phy->latency <= 0)
return -ENODEV;

Expand All @@ -384,11 +349,11 @@ static int st33zp24_spi_probe(struct spi_device *dev)
}

/*
* st33zp24_spi_remove remove the TPM device
* tpm_st33_spi_remove remove the TPM device
* @param: client, the spi_device drescription (TPM SPI description).
* @return: 0 in case of success.
*/
static int st33zp24_spi_remove(struct spi_device *dev)
static int tpm_st33_spi_remove(struct spi_device *dev)
{
struct tpm_chip *chip = spi_get_drvdata(dev);

Expand All @@ -401,34 +366,29 @@ static const struct spi_device_id st33zp24_spi_id[] = {
};
MODULE_DEVICE_TABLE(spi, st33zp24_spi_id);

#ifdef CONFIG_OF
static const struct of_device_id of_st33zp24_spi_match[] = {
{ .compatible = "st,st33zp24-spi", },
{}
};
MODULE_DEVICE_TABLE(of, of_st33zp24_spi_match);

static const struct acpi_device_id st33zp24_spi_acpi_match[] = {
{"SMO3324"},
{}
};
MODULE_DEVICE_TABLE(acpi, st33zp24_spi_acpi_match);
#endif

static SIMPLE_DEV_PM_OPS(st33zp24_spi_ops, st33zp24_pm_suspend,
st33zp24_pm_resume);

static struct spi_driver st33zp24_spi_driver = {
static struct spi_driver tpm_st33_spi_driver = {
.driver = {
.name = TPM_ST33_SPI,
.pm = &st33zp24_spi_ops,
.of_match_table = of_match_ptr(of_st33zp24_spi_match),
.acpi_match_table = ACPI_PTR(st33zp24_spi_acpi_match),
},
.probe = st33zp24_spi_probe,
.remove = st33zp24_spi_remove,
.probe = tpm_st33_spi_probe,
.remove = tpm_st33_spi_remove,
.id_table = st33zp24_spi_id,
};

module_spi_driver(st33zp24_spi_driver);
module_spi_driver(tpm_st33_spi_driver);

MODULE_AUTHOR("TPM support ([email protected])");
MODULE_DESCRIPTION("STM TPM 1.2 SPI ST33 Driver");
Expand Down

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