Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67;
From:   <amirmizi6@gmail.com>
To:     <Eyal.Cohen@nuvoton.com>, <jarkko.sakkinen@linux.intel.com>,
        <oshrialkoby85@gmail.com>, <alexander.steffen@infineon.com>,
        <robh+dt@kernel.org>, <mark.rutland@arm.com>, <peterhuewe@gmx.de>,
        <jgg@ziepe.ca>, <arnd@arndb.de>, <gregkh@linuxfoundation.org>
CC:     <devicetree@vger.kernel.org>, <linux-kernel@vger.kernel.org>,
        <linux-integrity@vger.kernel.org>, <oshri.alkoby@nuvoton.com>,
        <tmaimon77@gmail.com>, <gcwilson@us.ibm.com>,
        <kgoldman@us.ibm.com>, <Dan.Morav@nuvoton.com>,
        <oren.tanami@nuvoton.com>, <shmulik.hager@nuvoton.com>,
        <amir.mizinski@nuvoton.com>, Amir Mizinski <amirmizi6@gmail.com>
Subject: [PATCH v4 7/7] tpm: tpm_tis: add tpm_tis_i2c driver
Date:   Tue, 31 Mar 2020 14:32:07 +0300
Message-ID: <20200331113207.107080-8-amirmizi6@gmail.com>
In-Reply-To: <20200331113207.107080-1-amirmizi6@gmail.com>
References: <20200331113207.107080-1-amirmizi6@gmail.com>
MIME-Version: 1.0
Content-Type: text/plain; charset="UTF-8"
Content-Transfer-Encoding: 8BIT
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

From: Amir Mizinski <amirmizi6@gmail.com>

Implements the functionality needed to communicate with an I2C TPM
according to the TCG TPM I2C Interface Specification.

Signed-off-by: Amir Mizinski <amirmizi6@gmail.com>
---
 drivers/char/tpm/Kconfig       |  12 ++
 drivers/char/tpm/Makefile      |   1 +
 drivers/char/tpm/tpm_tis_i2c.c | 292 +++++++++++++++++++++++++++++++++++++++++
 3 files changed, 305 insertions(+)
 create mode 100644 drivers/char/tpm/tpm_tis_i2c.c

diff --git a/drivers/char/tpm/Kconfig b/drivers/char/tpm/Kconfig
index aacdeed..b482bbf 100644
--- a/drivers/char/tpm/Kconfig
+++ b/drivers/char/tpm/Kconfig
@@ -74,6 +74,18 @@ config TCG_TIS_SPI_CR50
          If you have a H1 secure module running Cr50 firmware on SPI bus,
          say Yes and it will be accessible from within Linux.

+config TCG_TIS_I2C
+       tristate "TPM I2C Interface Specification"
+       depends on I2C
+        depends on CRC_CCITT
+       select TCG_TIS_CORE
+       ---help---
+         If you have a TPM security chip which is connected to a regular
+         I2C master (i.e. most embedded platforms) that is compliant with the
+         TCG TPM I2C Interface Specification say Yes and it will be accessible from
+         within Linux. To compile this driver as a module, choose  M here;
+         the module will be called tpm_tis_i2c.
+
 config TCG_TIS_I2C_ATMEL
        tristate "TPM Interface Specification 1.2 Interface (I2C - Atmel)"
        depends on I2C
diff --git a/drivers/char/tpm/Makefile b/drivers/char/tpm/Makefile
index 9567e51..97999cf 100644
--- a/drivers/char/tpm/Makefile
+++ b/drivers/char/tpm/Makefile
@@ -26,6 +26,7 @@ obj-$(CONFIG_TCG_TIS_SPI) += tpm_tis_spi.o
 tpm_tis_spi-y := tpm_tis_spi_main.o
 tpm_tis_spi-$(CONFIG_TCG_TIS_SPI_CR50) += tpm_tis_spi_cr50.o

+obj-$(CONFIG_TCG_TIS_I2C) += tpm_tis_i2c.o
 obj-$(CONFIG_TCG_TIS_I2C_ATMEL) += tpm_i2c_atmel.o
 obj-$(CONFIG_TCG_TIS_I2C_INFINEON) += tpm_i2c_infineon.o
 obj-$(CONFIG_TCG_TIS_I2C_NUVOTON) += tpm_i2c_nuvoton.o
diff --git a/drivers/char/tpm/tpm_tis_i2c.c b/drivers/char/tpm/tpm_tis_i2c.c
new file mode 100644
index 0000000..c10ec7e
--- /dev/null
+++ b/drivers/char/tpm/tpm_tis_i2c.c
@@ -0,0 +1,292 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (c) 2014-2019 Nuvoton Technology corporation
+ *
+ * TPM TIS I2C
+ *
+ * TPM TIS I2C Device Driver Interface for devices that implement the TPM I2C
+ * Interface defined by TCG PC Client Platform TPM Profile (PTP) Specification
+ * Revision 01.03 v22 at www.trustedcomputinggroup.org
+ */
+
+#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/acpi.h>
+#include <linux/freezer.h>
+#include <linux/crc-ccitt.h>
+
+#include <linux/module.h>
+#include <linux/i2c.h>
+#include <linux/gpio.h>
+#include <linux/of_irq.h>
+#include <linux/of_gpio.h>
+#include <linux/tpm.h>
+#include "tpm.h"
+#include "tpm_tis_core.h"
+
+#define TPM_LOC_SEL                    0x04
+#define TPM_I2C_INTERFACE_CAPABILITY   0x30
+#define TPM_I2C_DEVICE_ADDRESS         0x38
+#define TPM_DATA_CSUM_ENABLE           0x40
+#define TPM_DATA_CSUM                  0x44
+#define TPM_I2C_DID_VID                        0x48
+#define TPM_I2C_RID                    0x4C
+
+//#define I2C_IS_TPM2 1
+
+struct tpm_tis_i2c_phy {
+       struct tpm_tis_data priv;
+       struct i2c_client *i2c_client;
+       bool data_csum;
+       u8 *iobuf;
+};
+
+static inline struct tpm_tis_i2c_phy *to_tpm_tis_i2c_phy(struct tpm_tis_data *data)
+{
+       return container_of(data, struct tpm_tis_i2c_phy, priv);
+}
+
+static u8 address_to_register(u32 addr)
+{
+       addr &= 0xFFF;
+
+       switch (addr) {
+               // adapt register addresses that have changed compared to
+               // older TIS versions
+       case TPM_ACCESS(0):
+               return 0x04;
+       case TPM_LOC_SEL:
+               return 0x00;
+       case TPM_DID_VID(0):
+               return 0x48;
+       case TPM_RID(0):
+               return 0x4C;
+       default:
+               return addr;
+       }
+}
+
+static int tpm_tis_i2c_read_bytes(struct tpm_tis_data *data, u32 addr,
+                                 u16 len, u8 *result)
+{
+       struct tpm_tis_i2c_phy *phy = to_tpm_tis_i2c_phy(data);
+       int ret = 0;
+       int i = 0;
+       u8 reg = address_to_register(addr);
+       struct i2c_msg msgs[] = {
+               {
+                       .addr = phy->i2c_client->addr,
+                       .len = sizeof(reg),
+                       .buf = &reg,
+               },
+               {
+                       .addr = phy->i2c_client->addr,
+                       .len = len,
+                       .buf = result,
+                       .flags = I2C_M_RD,
+               },
+       };
+
+       do {
+               ret = i2c_transfer(phy->i2c_client->adapter, msgs,
+                                  ARRAY_SIZE(msgs));
+               usleep_range(250, 300); // wait default GUARD_TIME of 250µs
+
+       } while (ret < 0 && i++ < TPM_RETRY);
+
+       if (ret < 0)
+               return ret;
+
+
+       return 0;
+}
+
+static int tpm_tis_i2c_write_bytes(struct tpm_tis_data *data, u32 addr,
+                                  u16 len, const u8 *value)
+{
+       struct tpm_tis_i2c_phy *phy = to_tpm_tis_i2c_phy(data);
+       int ret = 0;
+       int i = 0;
+
+       if (phy->iobuf) {
+               if (len > TPM_BUFSIZE - 1)
+                       return -EIO;
+
+               phy->iobuf[0] = address_to_register(addr);
+               memcpy(phy->iobuf + 1, value, len);
+
+               {
+                       struct i2c_msg msgs[] = {
+                               {
+                                       .addr = phy->i2c_client->addr,
+                                       .len = len + 1,
+                                       .buf = phy->iobuf,
+                               },
+                       };
+
+                       do {
+                               ret = i2c_transfer(phy->i2c_client->adapter,
+                                                  msgs, ARRAY_SIZE(msgs));
+                               // wait default GUARD_TIME of 250µs
+                               usleep_range(250, 300);
+                       } while (ret < 0 && i++ < TPM_RETRY);
+               }
+       } else {
+               u8 reg = address_to_register(addr);
+
+               struct i2c_msg msgs[] = {
+                       {
+                               .addr = phy->i2c_client->addr,
+                               .len = sizeof(reg),
+                               .buf = &reg,
+                       },
+                       {
+                               .addr = phy->i2c_client->addr,
+                               .len = len,
+                               .buf = (u8 *)value,
+                               .flags = I2C_M_NOSTART,
+                       },
+               };
+               do {
+                       ret = i2c_transfer(phy->i2c_client->adapter, msgs,
+                                          ARRAY_SIZE(msgs));
+                       // wait default GUARD_TIME of 250µs
+                       usleep_range(250, 300);
+               } while (ret < 0 && i++ < TPM_RETRY);
+       }
+
+       if (ret < 0)
+               return ret;
+
+
+       return 0;
+}
+
+static bool tpm_tis_i2c_check_data(struct tpm_tis_data *data,
+                                  const u8 *buf, size_t len)
+{
+       struct tpm_tis_i2c_phy *phy = to_tpm_tis_i2c_phy(data);
+       u16 crc, crc_tpm;
+       int rc;
+
+       if (phy->data_csum) {
+               crc = crc_ccitt(0x0000, buf, len);
+               rc = tpm_tis_read16(data, TPM_DATA_CSUM, &crc_tpm);
+               if (rc < 0)
+                       return false;
+
+               crc_tpm = be16_to_cpu(crc_tpm);
+               return crc == crc_tpm;
+       }
+
+       return true;
+}
+
+static SIMPLE_DEV_PM_OPS(tpm_tis_pm, tpm_pm_suspend, tpm_tis_resume);
+
+static int csum_state_store(struct tpm_tis_data *data, u8 new_state)
+{
+       struct tpm_tis_i2c_phy *phy = to_tpm_tis_i2c_phy(data);
+       u8 cur_state;
+       int rc;
+
+       rc = tpm_tis_i2c_write_bytes(&phy->priv, TPM_DATA_CSUM_ENABLE,
+                                    1, &new_state);
+       if (rc < 0)
+               return rc;
+
+       rc = tpm_tis_i2c_read_bytes(&phy->priv, TPM_DATA_CSUM_ENABLE,
+                                   1, &cur_state);
+       if (rc < 0)
+               return rc;
+
+       if (new_state == cur_state)
+               phy->data_csum = (bool)new_state;
+
+       return rc;
+}
+
+static const struct tpm_tis_phy_ops tpm_i2c_phy_ops = {
+       .read_bytes = tpm_tis_i2c_read_bytes,
+       .write_bytes = tpm_tis_i2c_write_bytes,
+       .check_data = tpm_tis_i2c_check_data,
+};
+
+static int tpm_tis_i2c_probe(struct i2c_client *dev,
+                            const struct i2c_device_id *id)
+{
+       struct tpm_tis_i2c_phy *phy;
+       int rc;
+       int CRC_Checksum = 0;
+       const u8 loc_init = 0;
+       struct device_node *np;
+
+       phy = devm_kzalloc(&dev->dev, sizeof(struct tpm_tis_i2c_phy),
+                          GFP_KERNEL);
+       if (!phy)
+               return -ENOMEM;
+
+       phy->i2c_client = dev;
+
+       if (!i2c_check_functionality(dev->adapter, I2C_FUNC_NOSTART)) {
+               phy->iobuf = devm_kmalloc(&dev->dev, TPM_BUFSIZE, GFP_KERNEL);
+               if (!phy->iobuf)
+                       return -ENOMEM;
+       }
+
+       // select locality 0 (the driver will access only via locality 0)
+       rc = tpm_tis_i2c_write_bytes(&phy->priv, TPM_LOC_SEL, 1, &loc_init);
+       if (rc < 0)
+               return rc;
+
+       // set CRC checksum calculation enable
+       np = dev->dev.of_node;
+       if (of_property_read_bool(np, "crc-checksum"))
+               CRC_Checksum = 1;
+
+       rc = csum_state_store(&phy->priv, CRC_Checksum);
+       if (rc < 0)
+               return rc;
+
+       return tpm_tis_core_init(&dev->dev, &phy->priv, -1, &tpm_i2c_phy_ops,
+                                       NULL);
+}
+
+static const struct i2c_device_id tpm_tis_i2c_id[] = {
+       {"tpm_tis_i2c", 0},
+       {}
+};
+MODULE_DEVICE_TABLE(i2c, tpm_tis_i2c_id);
+
+static const struct of_device_id of_tis_i2c_match[] = {
+       { .compatible = "tcg,tpm-tis-i2c", },
+       {}
+};
+MODULE_DEVICE_TABLE(of, of_tis_i2c_match);
+
+static const struct acpi_device_id acpi_tis_i2c_match[] = {
+       {"SMO0768", 0},
+       {}
+};
+MODULE_DEVICE_TABLE(acpi, acpi_tis_i2c_match);
+
+static struct i2c_driver tpm_tis_i2c_driver = {
+       .driver = {
+               .owner = THIS_MODULE,
+               .name = "tpm_tis_i2c",
+               .pm = &tpm_tis_pm,
+               .of_match_table = of_match_ptr(of_tis_i2c_match),
+               .acpi_match_table = ACPI_PTR(acpi_tis_i2c_match),
+       },
+       .probe = tpm_tis_i2c_probe,
+       .id_table = tpm_tis_i2c_id,
+};
+
+module_i2c_driver(tpm_tis_i2c_driver);
+
+MODULE_DESCRIPTION("TPM Driver for native I2C access");
+MODULE_LICENSE("GPL");
--
2.7.4


===========================================================================================
The privileged confidential information contained in this email is intended for use only by the addressees as indicated by the original sender of this email. If you are not the addressee indicated in this email or are not responsible for delivery of the email to such a person, please kindly reply to the sender indicating this fact and delete all copies of it from your computer and network server immediately. Your cooperation is highly appreciated. It is advised that any unauthorized use of confidential information of Nuvoton is strictly prohibited; and any information in this email irrelevant to the official business of Nuvoton shall be deemed as neither given nor endorsed by Nuvoton.