tpm/st33zp24/spi: Add st33zp24 spi phy

st33zp24 TIS 1.2 support also SPI. It is using a proprietary protocol to
transport TIS data.

Acked-by: Jarkko Sakkinen <jarkko.sakknen@linux.intel.com>
Reviewed-by: Jason Gunthorpe <jason.gunthorpe@obsidianresearch.com>
Signed-off-by: Christophe Ricard <christophe-h.ricard@st.com>
Signed-off-by: Peter Huewe <peterhuewe@gmx.de>

5 files changed, 408 insertions, 2 deletions

diff --git a/drivers/char/tpm/st33zp24/Kconfig b/drivers/char/tpm/st33zp24/Kconfig
index 51dcef520d3f..09cb727864f0 100644
--- a/drivers/char/tpm/st33zp24/Kconfig
+++ b/drivers/char/tpm/st33zp24/Kconfig
@@ -18,3 +18,13 @@ config TCG_TIS_ST33ZP24_I2C
           ST33ZP24 with i2c interface.
           To compile this driver as a module, choose M here; the module will be
           called tpm_st33zp24_i2c.
+
+config TCG_TIS_ST33ZP24_SPI
+        tristate "TPM 1.2 ST33ZP24 SPI support"
+        depends on TCG_TIS_ST33ZP24
+        depends on SPI
+        ---help---
+          This module adds support for the STMicroelectronics TPM security chip
+          ST33ZP24 with spi interface.
+          To compile this driver as a module, choose M here; the module will be
+          called tpm_st33zp24_spi.
diff --git a/drivers/char/tpm/st33zp24/Makefile b/drivers/char/tpm/st33zp24/Makefile
index 414497f00e5a..74a722e5e068 100644
--- a/drivers/char/tpm/st33zp24/Makefile
+++ b/drivers/char/tpm/st33zp24/Makefile
@@ -7,3 +7,6 @@ obj-$(CONFIG_TCG_TIS_ST33ZP24) += tpm_st33zp24.o
 
 tpm_st33zp24_i2c-objs = i2c.o
 obj-$(CONFIG_TCG_TIS_ST33ZP24_I2C) += tpm_st33zp24_i2c.o
+
+tpm_st33zp24_spi-objs = spi.o
+obj-$(CONFIG_TCG_TIS_ST33ZP24_SPI) += tpm_st33zp24_spi.o
diff --git a/drivers/char/tpm/st33zp24/i2c.c b/drivers/char/tpm/st33zp24/i2c.c
index 95e3091c4590..ad1ee180e0c2 100644
--- a/drivers/char/tpm/st33zp24/i2c.c
+++ b/drivers/char/tpm/st33zp24/i2c.c
@@ -27,8 +27,6 @@
 #include "st33zp24.h"
 
 #define TPM_DUMMY_BYTE                  0xAA
-#define TPM_WRITE_DIRECTION             0x80
-#define TPM_BUFSIZE                     2048
 
 struct st33zp24_i2c_phy {
         struct i2c_client *client;
diff --git a/drivers/char/tpm/st33zp24/spi.c b/drivers/char/tpm/st33zp24/spi.c
new file mode 100644
index 000000000000..7f4a5a46f0df
--- /dev/null
+++ b/drivers/char/tpm/st33zp24/spi.c
@@ -0,0 +1,392 @@
+/*
+ * STMicroelectronics TPM SPI Linux driver for TPM ST33ZP24
+ * 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
+ * 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/>.
+ */
+
+#include <linux/module.h>
+#include <linux/spi/spi.h>
+#include <linux/gpio.h>
+#include <linux/of_irq.h>
+#include <linux/of_gpio.h>
+#include <linux/tpm.h>
+#include <linux/platform_data/st33zp24.h>
+
+#include "st33zp24.h"
+
+#define TPM_DATA_FIFO           0x24
+#define TPM_INTF_CAPABILITY     0x14
+
+#define TPM_DUMMY_BYTE          0x00
+
+#define MAX_SPI_LATENCY         15
+#define LOCALITY0               0
+
+#define ST33ZP24_OK                                     0x5A
+#define ST33ZP24_UNDEFINED_ERR                          0x80
+#define ST33ZP24_BADLOCALITY                            0x81
+#define ST33ZP24_TISREGISTER_UKNOWN                     0x82
+#define ST33ZP24_LOCALITY_NOT_ACTIVATED                 0x83
+#define ST33ZP24_HASH_END_BEFORE_HASH_START             0x84
+#define ST33ZP24_BAD_COMMAND_ORDER                      0x85
+#define ST33ZP24_INCORECT_RECEIVED_LENGTH               0x86
+#define ST33ZP24_TPM_FIFO_OVERFLOW                      0x89
+#define ST33ZP24_UNEXPECTED_READ_FIFO                   0x8A
+#define ST33ZP24_UNEXPECTED_WRITE_FIFO                  0x8B
+#define ST33ZP24_CMDRDY_SET_WHEN_PROCESSING_HASH_END    0x90
+#define ST33ZP24_DUMMY_BYTES                            0x00
+
+/*
+ * TPM command can be up to 2048 byte, A TPM response can be up to
+ * 1024 byte.
+ * Between command and response, there are latency byte (up to 15
+ * usually on st33zp24 2 are enough).
+ *
+ * Overall when sending a command and expecting an answer we need if
+ * worst case:
+ * 2048 (for the TPM command) + 1024 (for the TPM answer).  We need
+ * some latency byte before the answer is available (max 15).
+ * We have 2048 + 1024 + 15.
+ */
+#define ST33ZP24_SPI_BUFFER_SIZE (TPM_BUFSIZE + (TPM_BUFSIZE / 2) +\
+                                  MAX_SPI_LATENCY)
+
+
+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];
+
+        int io_lpcpd;
+        int latency;
+};
+
+static int st33zp24_status_to_errno(u8 code)
+{
+        switch (code) {
+        case ST33ZP24_OK:
+                return 0;
+        case ST33ZP24_UNDEFINED_ERR:
+        case ST33ZP24_BADLOCALITY:
+        case ST33ZP24_TISREGISTER_UKNOWN:
+        case ST33ZP24_LOCALITY_NOT_ACTIVATED:
+        case ST33ZP24_HASH_END_BEFORE_HASH_START:
+        case ST33ZP24_BAD_COMMAND_ORDER:
+        case ST33ZP24_UNEXPECTED_READ_FIFO:
+        case ST33ZP24_UNEXPECTED_WRITE_FIFO:
+        case ST33ZP24_CMDRDY_SET_WHEN_PROCESSING_HASH_END:
+                return -EPROTO;
+        case ST33ZP24_INCORECT_RECEIVED_LENGTH:
+        case ST33ZP24_TPM_FIFO_OVERFLOW:
+                return -EMSGSIZE;
+        case ST33ZP24_DUMMY_BYTES:
+                return -ENOSYS;
+        }
+        return code;
+}
+
+/*
+ * st33zp24_spi_send
+ * Send byte to 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 written
+ * @param: tpm_data, the tpm_data to write inside the tpm_register
+ * @param: tpm_size, The length of the data
+ * @return: should be zero if success else a negative error 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, nbr_dummy_bytes = 0, ret = 0;
+        struct st33zp24_spi_phy *phy = phy_id;
+        struct spi_device *dev = phy->spi_device;
+        u8 *tx_buf = (u8 *)phy->spi_xfer.tx_buf;
+        u8 *rx_buf = phy->spi_xfer.rx_buf;
+
+        /* Pre-Header */
+        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) {
+                tx_buf[total_length++] = tpm_size >> 8;
+                tx_buf[total_length++] = tpm_size;
+        }
+
+        memcpy(&tx_buf[total_length], tpm_data, tpm_size);
+        total_length += tpm_size;
+
+        nbr_dummy_bytes = phy->latency;
+        memset(&tx_buf[total_length], TPM_DUMMY_BYTE, nbr_dummy_bytes);
+
+        phy->spi_xfer.len = total_length + nbr_dummy_bytes;
+
+        ret = spi_sync_transfer(dev, &phy->spi_xfer, 1);
+        if (ret == 0)
+                ret = rx_buf[total_length + nbr_dummy_bytes - 1];
+
+        return st33zp24_status_to_errno(ret);
+} /* st33zp24_spi_send() */
+
+/*
+ * 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 read8_reg(void *phy_id, u8 tpm_register, u8 *tpm_data, int tpm_size)
+{
+        u8 data = 0;
+        int total_length = 0, nbr_dummy_bytes, ret;
+        struct st33zp24_spi_phy *phy = phy_id;
+        struct spi_device *dev = phy->spi_device;
+        u8 *tx_buf = (u8 *)phy->spi_xfer.tx_buf;
+        u8 *rx_buf = phy->spi_xfer.rx_buf;
+
+        /* Pre-Header */
+        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++;
+
+        nbr_dummy_bytes = phy->latency;
+        memset(&tx_buf[total_length], TPM_DUMMY_BYTE,
+               nbr_dummy_bytes + tpm_size);
+
+        phy->spi_xfer.len = total_length + nbr_dummy_bytes + tpm_size;
+
+        /* header + status byte + size of the data + status byte */
+        ret = spi_sync_transfer(dev, &phy->spi_xfer, 1);
+        if (tpm_size > 0 && ret == 0) {
+                ret = rx_buf[total_length + nbr_dummy_bytes - 1];
+
+                memcpy(tpm_data, rx_buf + total_length + nbr_dummy_bytes,
+                       tpm_size);
+        }
+
+        return ret;
+} /* read8_reg() */
+
+/*
+ * st33zp24_spi_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: number of byte read successfully: should be one if success.
+ */
+static int st33zp24_spi_recv(void *phy_id, u8 tpm_register, u8 *tpm_data,
+                             int tpm_size)
+{
+        int ret;
+
+        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 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 = read8_reg(phy_id, TPM_INTF_CAPABILITY, &data, 1);
+                latency++;
+        }
+        return latency - 1;
+} /* evaluate_latency() */
+
+static const struct st33zp24_phy_ops spi_phy_ops = {
+        .send = st33zp24_spi_send,
+        .recv = st33zp24_spi_recv,
+};
+
+#ifdef CONFIG_OF
+static int tpm_stm_spi_of_request_resources(struct st33zp24_spi_phy *phy)
+{
+        struct device_node *pp;
+        struct spi_device *dev = phy->spi_device;
+        int gpio;
+        int ret;
+
+        pp = dev->dev.of_node;
+        if (!pp) {
+                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(&dev->dev,
+                        "Failed to retrieve lpcpd-gpios from dts.\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;
+        }
+        /* GPIO request and configuration */
+        ret = devm_gpio_request_one(&dev->dev, gpio,
+                        GPIOF_OUT_INIT_HIGH, "TPM IO LPCPD");
+        if (ret) {
+                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 tpm_stm_spi_request_resources(struct spi_device *dev,
+                                         struct st33zp24_spi_phy *phy)
+{
+        struct st33zp24_platform_data *pdata;
+        int ret;
+
+        pdata = dev->dev.platform_data;
+        if (!pdata) {
+                dev_err(&dev->dev, "No platform data\n");
+                return -ENODEV;
+        }
+
+        /* store for late use */
+        phy->io_lpcpd = pdata->io_lpcpd;
+
+        if (gpio_is_valid(pdata->io_lpcpd)) {
+                ret = devm_gpio_request_one(&dev->dev,
+                                pdata->io_lpcpd, GPIOF_OUT_INIT_HIGH,
+                                "TPM IO_LPCPD");
+                if (ret) {
+                        dev_err(&dev->dev, "%s : reset gpio_request failed\n",
+                                __FILE__);
+                        return ret;
+                }
+        }
+
+        return 0;
+}
+
+/*
+ * 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
+tpm_st33_spi_probe(struct spi_device *dev)
+{
+        int ret;
+        struct st33zp24_platform_data *pdata;
+        struct st33zp24_spi_phy *phy;
+
+        /* Check SPI platform functionnalities */
+        if (!dev) {
+                pr_info("%s: dev is NULL. Device is not accessible.\n",
+                        __func__);
+                return -ENODEV;
+        }
+
+        phy = devm_kzalloc(&dev->dev, sizeof(struct st33zp24_spi_phy),
+                           GFP_KERNEL);
+        if (!phy)
+                return -ENOMEM;
+
+        phy->spi_device = dev;
+        pdata = dev->dev.platform_data;
+        if (!pdata && dev->dev.of_node) {
+                ret = tpm_stm_spi_of_request_resources(phy);
+                if (ret)
+                        return ret;
+        } else if (pdata) {
+                ret = tpm_stm_spi_request_resources(dev, phy);
+                if (ret)
+                        return ret;
+        }
+
+        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;
+
+        return st33zp24_probe(phy, &spi_phy_ops, &dev->dev, dev->irq,
+                              phy->io_lpcpd);
+}
+
+/*
+ * 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 tpm_st33_spi_remove(struct spi_device *dev)
+{
+        struct tpm_chip *chip = spi_get_drvdata(dev);
+
+        return st33zp24_remove(chip);
+}
+
+#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);
+#endif
+
+static SIMPLE_DEV_PM_OPS(st33zp24_spi_ops, st33zp24_pm_suspend,
+                         st33zp24_pm_resume);
+
+static struct spi_driver tpm_st33_spi_driver = {
+        .driver = {
+                .owner = THIS_MODULE,
+                .name = TPM_ST33_SPI,
+                .pm = &st33zp24_spi_ops,
+                .of_match_table = of_match_ptr(of_st33zp24_spi_match),
+        },
+        .probe = tpm_st33_spi_probe,
+        .remove = tpm_st33_spi_remove,
+};
+
+module_spi_driver(tpm_st33_spi_driver);
+
+MODULE_AUTHOR("TPM support (TPMsupport@list.st.com)");
+MODULE_DESCRIPTION("STM TPM 1.2 SPI ST33 Driver");
+MODULE_VERSION("1.3.0");
+MODULE_LICENSE("GPL");
diff --git a/drivers/char/tpm/st33zp24/st33zp24.h b/drivers/char/tpm/st33zp24/st33zp24.h
index 43ad39a27f8d..c207cebf67dd 100644
--- a/drivers/char/tpm/st33zp24/st33zp24.h
+++ b/drivers/char/tpm/st33zp24/st33zp24.h
@@ -18,6 +18,9 @@
 #ifndef __LOCAL_ST33ZP24_H__
 #define __LOCAL_ST33ZP24_H__
 
+#define TPM_WRITE_DIRECTION             0x80
+#define TPM_BUFSIZE                     2048
+
 struct st33zp24_phy_ops {
         int (*send)(void *phy_id, u8 tpm_register, u8 *tpm_data, int tpm_size);
         int (*recv)(void *phy_id, u8 tpm_register, u8 *tpm_data, int tpm_size);