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path: root/drivers/char/tpm/tpm_tis_spi.c
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Diffstat (limited to 'drivers/char/tpm/tpm_tis_spi.c')
-rw-r--r--drivers/char/tpm/tpm_tis_spi.c272
1 files changed, 272 insertions, 0 deletions
diff --git a/drivers/char/tpm/tpm_tis_spi.c b/drivers/char/tpm/tpm_tis_spi.c
new file mode 100644
index 000000000000..dbaad9c681e3
--- /dev/null
+++ b/drivers/char/tpm/tpm_tis_spi.c
@@ -0,0 +1,272 @@
+/*
+ * Copyright (C) 2015 Infineon Technologies AG
+ * Copyright (C) 2016 STMicroelectronics SAS
+ *
+ * Authors:
+ * Peter Huewe <peter.huewe@infineon.com>
+ * Christophe Ricard <christophe-h.ricard@st.com>
+ *
+ * Maintained by: <tpmdd-devel@lists.sourceforge.net>
+ *
+ * Device driver for TCG/TCPA TPM (trusted platform module).
+ * Specifications at www.trustedcomputinggroup.org
+ *
+ * This device driver implements the TPM interface as defined in
+ * the TCG TPM Interface Spec version 1.3, revision 27 via _raw/native
+ * SPI access_.
+ *
+ * It is based on the original tpm_tis device driver from Leendert van
+ * Dorn and Kyleen Hall and Jarko Sakkinnen.
+ *
+ * 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, version 2 of the
+ * License.
+ */
+
+#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/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 "tpm.h"
+#include "tpm_tis_core.h"
+
+#define MAX_SPI_FRAMESIZE 64
+
+struct tpm_tis_spi_phy {
+ struct tpm_tis_data priv;
+ struct spi_device *spi_device;
+
+ u8 tx_buf[MAX_SPI_FRAMESIZE + 4];
+ u8 rx_buf[MAX_SPI_FRAMESIZE + 4];
+};
+
+static inline struct tpm_tis_spi_phy *to_tpm_tis_spi_phy(struct tpm_tis_data *data)
+{
+ return container_of(data, struct tpm_tis_spi_phy, priv);
+}
+
+static int tpm_tis_spi_read_bytes(struct tpm_tis_data *data, u32 addr,
+ u16 len, u8 *result)
+{
+ struct tpm_tis_spi_phy *phy = to_tpm_tis_spi_phy(data);
+ int ret, i;
+ struct spi_message m;
+ struct spi_transfer spi_xfer = {
+ .tx_buf = phy->tx_buf,
+ .rx_buf = phy->rx_buf,
+ .len = 4,
+ };
+
+ if (len > MAX_SPI_FRAMESIZE)
+ return -ENOMEM;
+
+ phy->tx_buf[0] = 0x80 | (len - 1);
+ phy->tx_buf[1] = 0xd4;
+ phy->tx_buf[2] = (addr >> 8) & 0xFF;
+ phy->tx_buf[3] = addr & 0xFF;
+
+ spi_xfer.cs_change = 1;
+ spi_message_init(&m);
+ spi_message_add_tail(&spi_xfer, &m);
+
+ spi_bus_lock(phy->spi_device->master);
+ ret = spi_sync_locked(phy->spi_device, &m);
+ if (ret < 0)
+ goto exit;
+
+ memset(phy->tx_buf, 0, len);
+
+ /* According to TCG PTP specification, if there is no TPM present at
+ * all, then the design has a weak pull-up on MISO. If a TPM is not
+ * present, a pull-up on MISO means that the SB controller sees a 1,
+ * and will latch in 0xFF on the read.
+ */
+ for (i = 0; (phy->rx_buf[0] & 0x01) == 0 && i < TPM_RETRY; i++) {
+ spi_xfer.len = 1;
+ spi_message_init(&m);
+ spi_message_add_tail(&spi_xfer, &m);
+ ret = spi_sync_locked(phy->spi_device, &m);
+ if (ret < 0)
+ goto exit;
+ }
+
+ spi_xfer.cs_change = 0;
+ spi_xfer.len = len;
+ spi_xfer.rx_buf = result;
+
+ spi_message_init(&m);
+ spi_message_add_tail(&spi_xfer, &m);
+ ret = spi_sync_locked(phy->spi_device, &m);
+
+exit:
+ spi_bus_unlock(phy->spi_device->master);
+ return ret;
+}
+
+static int tpm_tis_spi_write_bytes(struct tpm_tis_data *data, u32 addr,
+ u16 len, u8 *value)
+{
+ struct tpm_tis_spi_phy *phy = to_tpm_tis_spi_phy(data);
+ int ret, i;
+ struct spi_message m;
+ struct spi_transfer spi_xfer = {
+ .tx_buf = phy->tx_buf,
+ .rx_buf = phy->rx_buf,
+ .len = 4,
+ };
+
+ if (len > MAX_SPI_FRAMESIZE)
+ return -ENOMEM;
+
+ phy->tx_buf[0] = len - 1;
+ phy->tx_buf[1] = 0xd4;
+ phy->tx_buf[2] = (addr >> 8) & 0xFF;
+ phy->tx_buf[3] = addr & 0xFF;
+
+ spi_xfer.cs_change = 1;
+ spi_message_init(&m);
+ spi_message_add_tail(&spi_xfer, &m);
+
+ spi_bus_lock(phy->spi_device->master);
+ ret = spi_sync_locked(phy->spi_device, &m);
+ if (ret < 0)
+ goto exit;
+
+ memset(phy->tx_buf, 0, len);
+
+ /* According to TCG PTP specification, if there is no TPM present at
+ * all, then the design has a weak pull-up on MISO. If a TPM is not
+ * present, a pull-up on MISO means that the SB controller sees a 1,
+ * and will latch in 0xFF on the read.
+ */
+ for (i = 0; (phy->rx_buf[0] & 0x01) == 0 && i < TPM_RETRY; i++) {
+ spi_xfer.len = 1;
+ spi_message_init(&m);
+ spi_message_add_tail(&spi_xfer, &m);
+ ret = spi_sync_locked(phy->spi_device, &m);
+ if (ret < 0)
+ goto exit;
+ }
+
+ spi_xfer.len = len;
+ spi_xfer.tx_buf = value;
+ spi_xfer.cs_change = 0;
+ spi_xfer.tx_buf = value;
+ spi_message_init(&m);
+ spi_message_add_tail(&spi_xfer, &m);
+ ret = spi_sync_locked(phy->spi_device, &m);
+
+exit:
+ spi_bus_unlock(phy->spi_device->master);
+ return ret;
+}
+
+static int tpm_tis_spi_read16(struct tpm_tis_data *data, u32 addr, u16 *result)
+{
+ int rc;
+
+ rc = data->phy_ops->read_bytes(data, addr, sizeof(u16), (u8 *)result);
+ if (!rc)
+ *result = le16_to_cpu(*result);
+ return rc;
+}
+
+static int tpm_tis_spi_read32(struct tpm_tis_data *data, u32 addr, u32 *result)
+{
+ int rc;
+
+ rc = data->phy_ops->read_bytes(data, addr, sizeof(u32), (u8 *)result);
+ if (!rc)
+ *result = le32_to_cpu(*result);
+ return rc;
+}
+
+static int tpm_tis_spi_write32(struct tpm_tis_data *data, u32 addr, u32 value)
+{
+ value = cpu_to_le32(value);
+ return data->phy_ops->write_bytes(data, addr, sizeof(u32),
+ (u8 *)&value);
+}
+
+static const struct tpm_tis_phy_ops tpm_spi_phy_ops = {
+ .read_bytes = tpm_tis_spi_read_bytes,
+ .write_bytes = tpm_tis_spi_write_bytes,
+ .read16 = tpm_tis_spi_read16,
+ .read32 = tpm_tis_spi_read32,
+ .write32 = tpm_tis_spi_write32,
+};
+
+static int tpm_tis_spi_probe(struct spi_device *dev)
+{
+ struct tpm_tis_spi_phy *phy;
+
+ phy = devm_kzalloc(&dev->dev, sizeof(struct tpm_tis_spi_phy),
+ GFP_KERNEL);
+ if (!phy)
+ return -ENOMEM;
+
+ phy->spi_device = dev;
+
+ return tpm_tis_core_init(&dev->dev, &phy->priv, -1, &tpm_spi_phy_ops,
+ NULL);
+}
+
+static SIMPLE_DEV_PM_OPS(tpm_tis_pm, tpm_pm_suspend, tpm_tis_resume);
+
+static int tpm_tis_spi_remove(struct spi_device *dev)
+{
+ struct tpm_chip *chip = spi_get_drvdata(dev);
+
+ tpm_chip_unregister(chip);
+ tpm_tis_remove(chip);
+ return 0;
+}
+
+static const struct spi_device_id tpm_tis_spi_id[] = {
+ {"tpm_tis_spi", 0},
+ {}
+};
+MODULE_DEVICE_TABLE(spi, tpm_tis_spi_id);
+
+static const struct of_device_id of_tis_spi_match[] = {
+ { .compatible = "st,st33htpm-spi", },
+ { .compatible = "infineon,slb9670", },
+ { .compatible = "tcg,tpm_tis-spi", },
+ {}
+};
+MODULE_DEVICE_TABLE(of, of_tis_spi_match);
+
+static const struct acpi_device_id acpi_tis_spi_match[] = {
+ {"SMO0768", 0},
+ {}
+};
+MODULE_DEVICE_TABLE(acpi, acpi_tis_spi_match);
+
+static struct spi_driver tpm_tis_spi_driver = {
+ .driver = {
+ .owner = THIS_MODULE,
+ .name = "tpm_tis_spi",
+ .pm = &tpm_tis_pm,
+ .of_match_table = of_match_ptr(of_tis_spi_match),
+ .acpi_match_table = ACPI_PTR(acpi_tis_spi_match),
+ },
+ .probe = tpm_tis_spi_probe,
+ .remove = tpm_tis_spi_remove,
+ .id_table = tpm_tis_spi_id,
+};
+module_spi_driver(tpm_tis_spi_driver);
+
+MODULE_DESCRIPTION("TPM Driver for native SPI access");
+MODULE_LICENSE("GPL");
generated by cgit v1.2.3-58-ga151 (git 2.39.0) at 2024-11-27 21:34:19 +0000