--- /dev/null
+/*
+ * tpm_tis_i2c.c - QEMU's TPM TIS I2C Device
+ *
+ * Copyright (c) 2023 IBM Corporation
+ *
+ * Authors:
+ * Ninad Palsule <ninad@linux.ibm.com>
+ *
+ * This work is licensed under the terms of the GNU GPL, version 2 or later.
+ * See the COPYING file in the top-level directory.
+ *
+ * TPM I2C implementation follows TCG TPM I2c Interface specification,
+ * Family 2.0, Level 00, Revision 1.00
+ *
+ * TPM TIS for TPM 2 implementation following TCG PC Client Platform
+ * TPM Profile (PTP) Specification, Familiy 2.0, Revision 00.43
+ *
+ */
+
+#include "qemu/osdep.h"
+#include "hw/i2c/i2c.h"
+#include "hw/sysbus.h"
+#include "hw/acpi/tpm.h"
+#include "migration/vmstate.h"
+#include "tpm_prop.h"
+#include "qemu/log.h"
+#include "trace.h"
+#include "tpm_tis.h"
+
+/* Operations */
+#define OP_SEND 1
+#define OP_RECV 2
+
+/* Is locality valid */
+#define TPM_TIS_I2C_IS_VALID_LOCTY(x) TPM_TIS_IS_VALID_LOCTY(x)
+
+typedef struct TPMStateI2C {
+ /*< private >*/
+ I2CSlave parent_obj;
+
+ uint8_t offset; /* offset into data[] */
+ uint8_t operation; /* OP_SEND & OP_RECV */
+ uint8_t data[5]; /* Data */
+
+ /* i2c registers */
+ uint8_t loc_sel; /* Current locality */
+ uint8_t csum_enable; /* Is checksum enabled */
+
+ /* Derived from the above */
+ const char *reg_name; /* Register name */
+ uint32_t tis_addr; /* Converted tis address including locty */
+
+ /*< public >*/
+ TPMState state; /* not a QOM object */
+
+} TPMStateI2C;
+
+DECLARE_INSTANCE_CHECKER(TPMStateI2C, TPM_TIS_I2C,
+ TYPE_TPM_TIS_I2C)
+
+/* Prototype */
+static inline void tpm_tis_i2c_to_tis_reg(TPMStateI2C *i2cst, uint8_t i2c_reg);
+
+/* Register map */
+typedef struct regMap {
+ uint8_t i2c_reg; /* I2C register */
+ uint16_t tis_reg; /* TIS register */
+ const char *reg_name; /* Register name */
+} I2CRegMap;
+
+/*
+ * The register values in the common code is different than the latest
+ * register numbers as per the spec hence add the conversion map
+ */
+static const I2CRegMap tpm_tis_reg_map[] = {
+ /*
+ * These registers are sent to TIS layer. The register with UNKNOWN
+ * mapping are not sent to TIS layer and handled in I2c layer.
+ * NOTE: Adding frequently used registers at the start
+ */
+ { TPM_I2C_REG_DATA_FIFO, TPM_TIS_REG_DATA_FIFO, "FIFO", },
+ { TPM_I2C_REG_STS, TPM_TIS_REG_STS, "STS", },
+ { TPM_I2C_REG_DATA_CSUM_GET, TPM_I2C_REG_UNKNOWN, "CSUM_GET", },
+ { TPM_I2C_REG_LOC_SEL, TPM_I2C_REG_UNKNOWN, "LOC_SEL", },
+ { TPM_I2C_REG_ACCESS, TPM_TIS_REG_ACCESS, "ACCESS", },
+ { TPM_I2C_REG_INT_ENABLE, TPM_TIS_REG_INT_ENABLE, "INTR_ENABLE",},
+ { TPM_I2C_REG_INT_CAPABILITY, TPM_I2C_REG_UNKNOWN, "INTR_CAP", },
+ { TPM_I2C_REG_INTF_CAPABILITY, TPM_TIS_REG_INTF_CAPABILITY, "INTF_CAP", },
+ { TPM_I2C_REG_DID_VID, TPM_TIS_REG_DID_VID, "DID_VID", },
+ { TPM_I2C_REG_RID, TPM_TIS_REG_RID, "RID", },
+ { TPM_I2C_REG_I2C_DEV_ADDRESS, TPM_I2C_REG_UNKNOWN, "DEV_ADDRESS",},
+ { TPM_I2C_REG_DATA_CSUM_ENABLE, TPM_I2C_REG_UNKNOWN, "CSUM_ENABLE",},
+};
+
+static int tpm_tis_i2c_pre_save(void *opaque)
+{
+ TPMStateI2C *i2cst = opaque;
+
+ return tpm_tis_pre_save(&i2cst->state);
+}
+
+static int tpm_tis_i2c_post_load(void *opaque, int version_id)
+{
+ TPMStateI2C *i2cst = opaque;
+
+ if (i2cst->offset >= 1) {
+ tpm_tis_i2c_to_tis_reg(i2cst, i2cst->data[0]);
+ }
+
+ return 0;
+}
+
+static const VMStateDescription vmstate_tpm_tis_i2c = {
+ .name = "tpm-tis-i2c",
+ .version_id = 0,
+ .pre_save = tpm_tis_i2c_pre_save,
+ .post_load = tpm_tis_i2c_post_load,
+ .fields = (VMStateField[]) {
+ VMSTATE_BUFFER(state.buffer, TPMStateI2C),
+ VMSTATE_UINT16(state.rw_offset, TPMStateI2C),
+ VMSTATE_UINT8(state.active_locty, TPMStateI2C),
+ VMSTATE_UINT8(state.aborting_locty, TPMStateI2C),
+ VMSTATE_UINT8(state.next_locty, TPMStateI2C),
+
+ VMSTATE_STRUCT_ARRAY(state.loc, TPMStateI2C, TPM_TIS_NUM_LOCALITIES, 0,
+ vmstate_locty, TPMLocality),
+
+ /* i2c specifics */
+ VMSTATE_UINT8(offset, TPMStateI2C),
+ VMSTATE_UINT8(operation, TPMStateI2C),
+ VMSTATE_BUFFER(data, TPMStateI2C),
+ VMSTATE_UINT8(loc_sel, TPMStateI2C),
+ VMSTATE_UINT8(csum_enable, TPMStateI2C),
+
+ VMSTATE_END_OF_LIST()
+ }
+};
+
+/*
+ * Set data value. The i2cst->offset is not updated as called in
+ * the read path.
+ */
+static void tpm_tis_i2c_set_data(TPMStateI2C *i2cst, uint32_t data)
+{
+ i2cst->data[1] = data;
+ i2cst->data[2] = data >> 8;
+ i2cst->data[3] = data >> 16;
+ i2cst->data[4] = data >> 24;
+}
+/*
+ * Generate interface capability based on what is returned by TIS and what is
+ * expected by I2C. Save the capability in the data array overwriting the TIS
+ * capability.
+ */
+static uint32_t tpm_tis_i2c_interface_capability(TPMStateI2C *i2cst,
+ uint32_t tis_cap)
+{
+ uint32_t i2c_cap;
+
+ /* Now generate i2c capability */
+ i2c_cap = (TPM_I2C_CAP_INTERFACE_TYPE |
+ TPM_I2C_CAP_INTERFACE_VER |
+ TPM_I2C_CAP_TPM2_FAMILY |
+ TPM_I2C_CAP_LOCALITY_CAP |
+ TPM_I2C_CAP_BUS_SPEED |
+ TPM_I2C_CAP_DEV_ADDR_CHANGE);
+
+ /* Now check the TIS and set some capabilities */
+
+ /* Static burst count set */
+ if (tis_cap & TPM_TIS_CAP_BURST_COUNT_STATIC) {
+ i2c_cap |= TPM_I2C_CAP_BURST_COUNT_STATIC;
+ }
+
+ return i2c_cap;
+}
+
+/* Convert I2C register to TIS address and returns the name of the register */
+static inline void tpm_tis_i2c_to_tis_reg(TPMStateI2C *i2cst, uint8_t i2c_reg)
+{
+ const I2CRegMap *reg_map;
+ int i;
+
+ i2cst->tis_addr = 0xffffffff;
+
+ /* Special case for the STS register. */
+ if (i2c_reg >= TPM_I2C_REG_STS && i2c_reg <= TPM_I2C_REG_STS + 3) {
+ i2c_reg = TPM_I2C_REG_STS;
+ }
+
+ for (i = 0; i < ARRAY_SIZE(tpm_tis_reg_map); i++) {
+ reg_map = &tpm_tis_reg_map[i];
+ if (reg_map->i2c_reg == i2c_reg) {
+ i2cst->reg_name = reg_map->reg_name;
+ i2cst->tis_addr = reg_map->tis_reg;
+
+ /* Include the locality in the address. */
+ assert(TPM_TIS_I2C_IS_VALID_LOCTY(i2cst->loc_sel));
+ i2cst->tis_addr += (i2cst->loc_sel << TPM_TIS_LOCALITY_SHIFT);
+ break;
+ }
+ }
+}
+
+/* Clear some fields from the structure. */
+static inline void tpm_tis_i2c_clear_data(TPMStateI2C *i2cst)
+{
+ /* Clear operation and offset */
+ i2cst->operation = 0;
+ i2cst->offset = 0;
+ i2cst->tis_addr = 0xffffffff;
+ i2cst->reg_name = NULL;
+ memset(i2cst->data, 0, sizeof(i2cst->data));
+
+ return;
+}
+
+/* Send data to TPM */
+static inline void tpm_tis_i2c_tpm_send(TPMStateI2C *i2cst)
+{
+ uint32_t data;
+ size_t offset = 0;
+ uint32_t sz = 4;
+
+ if ((i2cst->operation == OP_SEND) && (i2cst->offset > 1)) {
+
+ switch (i2cst->data[0]) {
+ case TPM_I2C_REG_DATA_CSUM_ENABLE:
+ /*
+ * Checksum is not handled by TIS code hence we will consume the
+ * register here.
+ */
+ i2cst->csum_enable = i2cst->data[1] & TPM_DATA_CSUM_ENABLED;
+ break;
+ case TPM_I2C_REG_DATA_FIFO:
+ /* Handled in the main i2c_send function */
+ break;
+ case TPM_I2C_REG_LOC_SEL:
+ /*
+ * This register is not handled by TIS so save the locality
+ * locally
+ */
+ if (TPM_TIS_I2C_IS_VALID_LOCTY(i2cst->data[1])) {
+ i2cst->loc_sel = i2cst->data[1];
+ }
+ break;
+ default:
+ /* We handle non-FIFO here */
+
+ /* Index 0 is a register. Convert byte stream to uint32_t */
+ data = i2cst->data[1];
+ data |= i2cst->data[2] << 8;
+ data |= i2cst->data[3] << 16;
+ data |= i2cst->data[4] << 24;
+
+ /* Add register specific masking */
+ switch (i2cst->data[0]) {
+ case TPM_I2C_REG_INT_ENABLE:
+ data &= TPM_I2C_INT_ENABLE_MASK;
+ break;
+ case TPM_I2C_REG_STS ... TPM_I2C_REG_STS + 3:
+ /*
+ * STS register has 4 bytes data.
+ * As per the specs following writes must be allowed.
+ * - From base address 1 to 4 bytes are allowed.
+ * - Single byte write to first or last byte must
+ * be allowed.
+ */
+ offset = i2cst->data[0] - TPM_I2C_REG_STS;
+ if (offset > 0) {
+ sz = 1;
+ }
+ data &= (TPM_I2C_STS_WRITE_MASK >> (offset * 8));
+ break;
+ }
+
+ tpm_tis_write_data(&i2cst->state, i2cst->tis_addr + offset, data,
+ sz);
+ break;
+ }
+
+ tpm_tis_i2c_clear_data(i2cst);
+ }
+
+ return;
+}
+
+/* Callback from TPM to indicate that response is copied */
+static void tpm_tis_i2c_request_completed(TPMIf *ti, int ret)
+{
+ TPMStateI2C *i2cst = TPM_TIS_I2C(ti);
+ TPMState *s = &i2cst->state;
+
+ /* Inform the common code. */
+ tpm_tis_request_completed(s, ret);
+}
+
+static enum TPMVersion tpm_tis_i2c_get_tpm_version(TPMIf *ti)
+{
+ TPMStateI2C *i2cst = TPM_TIS_I2C(ti);
+ TPMState *s = &i2cst->state;
+
+ return tpm_tis_get_tpm_version(s);
+}
+
+static int tpm_tis_i2c_event(I2CSlave *i2c, enum i2c_event event)
+{
+ TPMStateI2C *i2cst = TPM_TIS_I2C(i2c);
+ int ret = 0;
+
+ switch (event) {
+ case I2C_START_RECV:
+ trace_tpm_tis_i2c_event("START_RECV");
+ break;
+ case I2C_START_SEND:
+ trace_tpm_tis_i2c_event("START_SEND");
+ tpm_tis_i2c_clear_data(i2cst);
+ break;
+ case I2C_FINISH:
+ trace_tpm_tis_i2c_event("FINISH");
+ if (i2cst->operation == OP_SEND) {
+ tpm_tis_i2c_tpm_send(i2cst);
+ } else {
+ tpm_tis_i2c_clear_data(i2cst);
+ }
+ break;
+ default:
+ break;
+ }
+
+ return ret;
+}
+
+/*
+ * If data is for FIFO then it is received from tpm_tis_common buffer
+ * otherwise it will be handled using single call to common code and
+ * cached in the local buffer.
+ */
+static uint8_t tpm_tis_i2c_recv(I2CSlave *i2c)
+{
+ int ret = 0;
+ uint32_t data_read;
+ TPMStateI2C *i2cst = TPM_TIS_I2C(i2c);
+ TPMState *s = &i2cst->state;
+ uint16_t i2c_reg = i2cst->data[0];
+ size_t offset;
+
+ if (i2cst->operation == OP_RECV) {
+
+ /* Do not cache FIFO data. */
+ if (i2cst->data[0] == TPM_I2C_REG_DATA_FIFO) {
+ data_read = tpm_tis_read_data(s, i2cst->tis_addr, 1);
+ ret = (data_read & 0xff);
+ } else if (i2cst->offset < sizeof(i2cst->data)) {
+ ret = i2cst->data[i2cst->offset++];
+ }
+
+ } else if ((i2cst->operation == OP_SEND) && (i2cst->offset < 2)) {
+ /* First receive call after send */
+
+ i2cst->operation = OP_RECV;
+
+ switch (i2c_reg) {
+ case TPM_I2C_REG_LOC_SEL:
+ /* Location selection register is managed by i2c */
+ tpm_tis_i2c_set_data(i2cst, i2cst->loc_sel);
+ break;
+ case TPM_I2C_REG_DATA_FIFO:
+ /* FIFO data is directly read from TPM TIS */
+ data_read = tpm_tis_read_data(s, i2cst->tis_addr, 1);
+ tpm_tis_i2c_set_data(i2cst, (data_read & 0xff));
+ break;
+ case TPM_I2C_REG_DATA_CSUM_ENABLE:
+ tpm_tis_i2c_set_data(i2cst, i2cst->csum_enable);
+ break;
+ case TPM_I2C_REG_INT_CAPABILITY:
+ /*
+ * Interrupt is not supported in the linux kernel hence we cannot
+ * test this model with interrupts.
+ */
+ tpm_tis_i2c_set_data(i2cst, TPM_I2C_INT_ENABLE_MASK);
+ break;
+ case TPM_I2C_REG_DATA_CSUM_GET:
+ /*
+ * Checksum registers are not supported by common code hence
+ * call a common code to get the checksum.
+ */
+ data_read = tpm_tis_get_checksum(s);
+
+ /* Save the byte stream in data field */
+ tpm_tis_i2c_set_data(i2cst, data_read);
+ break;
+ default:
+ data_read = tpm_tis_read_data(s, i2cst->tis_addr, 4);
+
+ switch (i2c_reg) {
+ case TPM_I2C_REG_INTF_CAPABILITY:
+ /* Prepare the capabilities as per I2C interface */
+ data_read = tpm_tis_i2c_interface_capability(i2cst,
+ data_read);
+ break;
+ case TPM_I2C_REG_STS ... TPM_I2C_REG_STS + 3:
+ offset = i2c_reg - TPM_I2C_REG_STS;
+ /*
+ * As per specs, STS bit 31:26 are reserved and must
+ * be set to 0
+ */
+ data_read &= TPM_I2C_STS_READ_MASK;
+ /*
+ * STS register has 4 bytes data.
+ * As per the specs following reads must be allowed.
+ * - From base address 1 to 4 bytes are allowed.
+ * - Last byte must be allowed to read as a single byte
+ * - Second and third byte must be allowed to read as two
+ * two bytes.
+ */
+ data_read >>= (offset * 8);
+ break;
+ }
+
+ /* Save byte stream in data[] */
+ tpm_tis_i2c_set_data(i2cst, data_read);
+ break;
+ }
+
+ /* Return first byte with this call */
+ i2cst->offset = 1; /* keep the register value intact for debug */
+ ret = i2cst->data[i2cst->offset++];
+ } else {
+ i2cst->operation = OP_RECV;
+ }
+
+ trace_tpm_tis_i2c_recv(ret);
+
+ return ret;
+}
+
+/*
+ * Send function only remembers data in the buffer and then calls
+ * TPM TIS common code during FINISH event.
+ */
+static int tpm_tis_i2c_send(I2CSlave *i2c, uint8_t data)
+{
+ TPMStateI2C *i2cst = TPM_TIS_I2C(i2c);
+
+ /* Reject non-supported registers. */
+ if (i2cst->offset == 0) {
+ /* Convert I2C register to TIS register */
+ tpm_tis_i2c_to_tis_reg(i2cst, data);
+ if (i2cst->tis_addr == 0xffffffff) {
+ return 0xffffffff;
+ }
+
+ trace_tpm_tis_i2c_send_reg(i2cst->reg_name, data);
+
+ /* We do not support device address change */
+ if (data == TPM_I2C_REG_I2C_DEV_ADDRESS) {
+ qemu_log_mask(LOG_UNIMP, "%s: Device address change "
+ "is not supported.\n", __func__);
+ return 0xffffffff;
+ }
+ } else {
+ trace_tpm_tis_i2c_send(data);
+ }
+
+ if (i2cst->offset < sizeof(i2cst->data)) {
+ i2cst->operation = OP_SEND;
+
+ /*
+ * In two cases, we save values in the local buffer.
+ * 1) The first value is always a register.
+ * 2) In case of non-FIFO multibyte registers, TIS expects full
+ * register value hence I2C layer cache the register value and send
+ * to TIS during FINISH event.
+ */
+ if ((i2cst->offset == 0) ||
+ (i2cst->data[0] != TPM_I2C_REG_DATA_FIFO)) {
+ i2cst->data[i2cst->offset++] = data;
+ } else {
+ /*
+ * The TIS can process FIFO data one byte at a time hence the FIFO
+ * data is sent to TIS directly.
+ */
+ tpm_tis_write_data(&i2cst->state, i2cst->tis_addr, data, 1);
+ }
+
+ return 0;
+ }
+
+ /* Return non-zero to indicate NAK */
+ return 1;
+}
+
+static Property tpm_tis_i2c_properties[] = {
+ DEFINE_PROP_TPMBE("tpmdev", TPMStateI2C, state.be_driver),
+ DEFINE_PROP_END_OF_LIST(),
+};
+
+static void tpm_tis_i2c_realizefn(DeviceState *dev, Error **errp)
+{
+ TPMStateI2C *i2cst = TPM_TIS_I2C(dev);
+ TPMState *s = &i2cst->state;
+
+ if (!tpm_find()) {
+ error_setg(errp, "at most one TPM device is permitted");
+ return;
+ }
+
+ /*
+ * Get the backend pointer. It is not initialized propery during
+ * device_class_set_props
+ */
+ s->be_driver = qemu_find_tpm_be("tpm0");
+
+ if (!s->be_driver) {
+ error_setg(errp, "'tpmdev' property is required");
+ return;
+ }
+}
+
+static void tpm_tis_i2c_reset(DeviceState *dev)
+{
+ TPMStateI2C *i2cst = TPM_TIS_I2C(dev);
+ TPMState *s = &i2cst->state;
+
+ tpm_tis_i2c_clear_data(i2cst);
+
+ i2cst->csum_enable = 0;
+ i2cst->loc_sel = 0x00;
+
+ return tpm_tis_reset(s);
+}
+
+static void tpm_tis_i2c_class_init(ObjectClass *klass, void *data)
+{
+ DeviceClass *dc = DEVICE_CLASS(klass);
+ I2CSlaveClass *k = I2C_SLAVE_CLASS(klass);
+ TPMIfClass *tc = TPM_IF_CLASS(klass);
+
+ dc->realize = tpm_tis_i2c_realizefn;
+ dc->reset = tpm_tis_i2c_reset;
+ dc->vmsd = &vmstate_tpm_tis_i2c;
+ device_class_set_props(dc, tpm_tis_i2c_properties);
+ set_bit(DEVICE_CATEGORY_MISC, dc->categories);
+
+ k->event = tpm_tis_i2c_event;
+ k->recv = tpm_tis_i2c_recv;
+ k->send = tpm_tis_i2c_send;
+
+ tc->model = TPM_MODEL_TPM_TIS;
+ tc->request_completed = tpm_tis_i2c_request_completed;
+ tc->get_version = tpm_tis_i2c_get_tpm_version;
+}
+
+static const TypeInfo tpm_tis_i2c_info = {
+ .name = TYPE_TPM_TIS_I2C,
+ .parent = TYPE_I2C_SLAVE,
+ .instance_size = sizeof(TPMStateI2C),
+ .class_init = tpm_tis_i2c_class_init,
+ .interfaces = (InterfaceInfo[]) {
+ { TYPE_TPM_IF },
+ { }
+ }
+};
+
+static void tpm_tis_i2c_register_types(void)
+{
+ type_register_static(&tpm_tis_i2c_info);
+}
+
+type_init(tpm_tis_i2c_register_types)
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