1 files changed, 298 insertions, 0 deletions
diff --git a/drivers/char/tpm/tpm_tis_spi_main.c b/drivers/char/tpm/tpm_tis_spi_main.c
new file mode 100644
index 000000000000..d1754fd6c573
--- /dev/null
+++ b/drivers/char/tpm/tpm_tis_spi_main.c
@@ -0,0 +1,298 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * 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.
+ */
+
+#include <linux/acpi.h>
+#include <linux/completion.h>
+#include <linux/init.h>
+#include <linux/interrupt.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/slab.h>
+
+#include <linux/of_device.h>
+#include <linux/spi/spi.h>
+#include <linux/tpm.h>
+
+#include "tpm.h"
+#include "tpm_tis_core.h"
+#include "tpm_tis_spi.h"
+
+#define MAX_SPI_FRAMESIZE 64
+
+/*
+ * TCG SPI flow control is documented in section 6.4 of the spec[1]. In short,
+ * keep trying to read from the device until MISO goes high indicating the
+ * wait state has ended.
+ *
+ * [1] https://trustedcomputinggroup.org/resource/pc-client-platform-tpm-profile-ptp-specification/
+ */
+static int tpm_tis_spi_flow_control(struct tpm_tis_spi_phy *phy,
+				    struct spi_transfer *spi_xfer)
+{
+	struct spi_message m;
+	int ret, i;
+
+	if ((phy->iobuf[3] & 0x01) == 0) {
+		// handle SPI wait states
+		phy->iobuf[0] = 0;
+
+		for (i = 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)
+				return ret;
+			if (phy->iobuf[0] & 0x01)
+				break;
+		}
+
+		if (i == TPM_RETRY)
+			return -ETIMEDOUT;
+	}
+
+	return 0;
+}
+
+int tpm_tis_spi_transfer(struct tpm_tis_data *data, u32 addr, u16 len,
+			 u8 *in, const u8 *out)
+{
+	struct tpm_tis_spi_phy *phy = to_tpm_tis_spi_phy(data);
+	int ret = 0;
+	struct spi_message m;
+	struct spi_transfer spi_xfer;
+	u8 transfer_len;
+
+	spi_bus_lock(phy->spi_device->master);
+
+	while (len) {
+		transfer_len = min_t(u16, len, MAX_SPI_FRAMESIZE);
+
+		phy->iobuf[0] = (in ? 0x80 : 0) | (transfer_len - 1);
+		phy->iobuf[1] = 0xd4;
+		phy->iobuf[2] = addr >> 8;
+		phy->iobuf[3] = addr;
+
+		memset(&spi_xfer, 0, sizeof(spi_xfer));
+		spi_xfer.tx_buf = phy->iobuf;
+		spi_xfer.rx_buf = phy->iobuf;
+		spi_xfer.len = 4;
+		spi_xfer.cs_change = 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;
+
+		ret = phy->flow_control(phy, &spi_xfer);
+		if (ret < 0)
+			goto exit;
+
+		spi_xfer.cs_change = 0;
+		spi_xfer.len = transfer_len;
+		spi_xfer.delay_usecs = 5;
+
+		if (in) {
+			spi_xfer.tx_buf = NULL;
+		} else if (out) {
+			spi_xfer.rx_buf = NULL;
+			memcpy(phy->iobuf, out, transfer_len);
+			out += transfer_len;
+		}
+
+		spi_message_init(&m);
+		spi_message_add_tail(&spi_xfer, &m);
+		reinit_completion(&phy->ready);
+		ret = spi_sync_locked(phy->spi_device, &m);
+		if (ret < 0)
+			goto exit;
+
+		if (in) {
+			memcpy(in, phy->iobuf, transfer_len);
+			in += transfer_len;
+		}
+
+		len -= transfer_len;
+	}
+
+exit:
+	spi_bus_unlock(phy->spi_device->master);
+	return ret;
+}
+
+static int tpm_tis_spi_read_bytes(struct tpm_tis_data *data, u32 addr,
+				  u16 len, u8 *result)
+{
+	return tpm_tis_spi_transfer(data, addr, len, result, NULL);
+}
+
+static int tpm_tis_spi_write_bytes(struct tpm_tis_data *data, u32 addr,
+				   u16 len, const u8 *value)
+{
+	return tpm_tis_spi_transfer(data, addr, len, NULL, value);
+}
+
+int tpm_tis_spi_read16(struct tpm_tis_data *data, u32 addr, u16 *result)
+{
+	__le16 result_le;
+	int rc;
+
+	rc = data->phy_ops->read_bytes(data, addr, sizeof(u16),
+				       (u8 *)&result_le);
+	if (!rc)
+		*result = le16_to_cpu(result_le);
+
+	return rc;
+}
+
+int tpm_tis_spi_read32(struct tpm_tis_data *data, u32 addr, u32 *result)
+{
+	__le32 result_le;
+	int rc;
+
+	rc = data->phy_ops->read_bytes(data, addr, sizeof(u32),
+				       (u8 *)&result_le);
+	if (!rc)
+		*result = le32_to_cpu(result_le);
+
+	return rc;
+}
+
+int tpm_tis_spi_write32(struct tpm_tis_data *data, u32 addr, u32 value)
+{
+	__le32 value_le;
+	int rc;
+
+	value_le = cpu_to_le32(value);
+	rc = data->phy_ops->write_bytes(data, addr, sizeof(u32),
+					(u8 *)&value_le);
+
+	return rc;
+}
+
+int tpm_tis_spi_init(struct spi_device *spi, struct tpm_tis_spi_phy *phy,
+		     int irq, const struct tpm_tis_phy_ops *phy_ops)
+{
+	phy->iobuf = devm_kmalloc(&spi->dev, MAX_SPI_FRAMESIZE, GFP_KERNEL);
+	if (!phy->iobuf)
+		return -ENOMEM;
+
+	phy->spi_device = spi;
+
+	return tpm_tis_core_init(&spi->dev, &phy->priv, irq, phy_ops, NULL);
+}
+
+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;
+	int irq;
+
+	phy = devm_kzalloc(&dev->dev, sizeof(struct tpm_tis_spi_phy),
+			   GFP_KERNEL);
+	if (!phy)
+		return -ENOMEM;
+
+	phy->flow_control = tpm_tis_spi_flow_control;
+
+	/* If the SPI device has an IRQ then use that */
+	if (dev->irq > 0)
+		irq = dev->irq;
+	else
+		irq = -1;
+
+	init_completion(&phy->ready);
+	return tpm_tis_spi_init(dev, phy, irq, &tpm_spi_phy_ops);
+}
+
+typedef int (*tpm_tis_spi_probe_func)(struct spi_device *);
+
+static int tpm_tis_spi_driver_probe(struct spi_device *spi)
+{
+	const struct spi_device_id *spi_dev_id = spi_get_device_id(spi);
+	tpm_tis_spi_probe_func probe_func;
+
+	probe_func = of_device_get_match_data(&spi->dev);
+	if (!probe_func && spi_dev_id)
+		probe_func = (tpm_tis_spi_probe_func)spi_dev_id->driver_data;
+	if (!probe_func)
+		return -ENODEV;
+
+	return probe_func(spi);
+}
+
+static SIMPLE_DEV_PM_OPS(tpm_tis_pm, tpm_pm_suspend, tpm_tis_spi_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", (unsigned long)tpm_tis_spi_probe },
+	{ "cr50", (unsigned long)cr50_spi_probe },
+	{}
+};
+MODULE_DEVICE_TABLE(spi, tpm_tis_spi_id);
+
+static const struct of_device_id of_tis_spi_match[] = {
+	{ .compatible = "st,st33htpm-spi", .data = tpm_tis_spi_probe },
+	{ .compatible = "infineon,slb9670", .data = tpm_tis_spi_probe },
+	{ .compatible = "tcg,tpm_tis-spi", .data = tpm_tis_spi_probe },
+	{ .compatible = "google,cr50", .data = cr50_spi_probe },
+	{}
+};
+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 = {
+		.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_driver_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");