tpm: Add support for TPM device over I2C bus

Qemu already supports devices attached to ISA and sysbus. This drop adds
support for the I2C bus attached TPM devices. I2C model only supports
TPM2 protocol.

This commit includes changes for the common code.
- Added I2C emulation model. Logic was added in the model to temporarily
  cache the data as I2C interface works per byte basis.
- New tpm type "tpm-tis-i2c" added for I2C support. The user has to
  provide this string on command line.

Testing:
  TPM I2C device module is tested using SWTPM (software based TPM
  package). Qemu uses the rainier machine and is connected to swtpm over
  the socket interface.

  The command to start swtpm is as follows:
  $ swtpm socket --tpmstate dir=/tmp/mytpm1    \
                 --ctrl type=unixio,path=/tmp/mytpm1/swtpm-sock  \
                 --tpm2 --log level=100

  The command to start qemu is as follows:
  $ qemu-system-arm -M rainier-bmc -nographic \
            -kernel ${IMAGEPATH}/fitImage-linux.bin \
            -dtb ${IMAGEPATH}/aspeed-bmc-ibm-rainier.dtb \
            -initrd ${IMAGEPATH}/obmc-phosphor-initramfs.rootfs.cpio.xz \
            -drive file=${IMAGEPATH}/obmc-phosphor-image.rootfs.wic.qcow2,if=sd,index=2 \
            -net nic -net user,hostfwd=:127.0.0.1:2222-:22,hostfwd=:127.0.0.1:2443-:443 \
            -chardev socket,id=chrtpm,path=/tmp/mytpm1/swtpm-sock \
            -tpmdev emulator,id=tpm0,chardev=chrtpm \
            -device tpm-tis-i2c,tpmdev=tpm0,bus=aspeed.i2c.bus.12,address=0x2e

Signed-off-by: Ninad Palsule <ninad@linux.ibm.com>
Reviewed-by: Stefan Berger <stefanb@linux.ibm.com>
Tested-by: Stefan Berger <stefanb@linux.ibm.com>
Reviewed-by: Cédric Le Goater <clg@kaod.org>
Reviewed-by: Joel Stanley <joel@jms.id.au>
Tested-by: Joel Stanley <joel@jms.id.au>
Message-id: 20230414220754.1191476-4-ninadpalsule@us.ibm.com

hw/arm/Kconfig

@@ -6,6 +6,7 @@ config ARM_VIRT
     imply VFIO_PLATFORM
     imply VFIO_XGMAC
     imply TPM_TIS_SYSBUS
+    imply TPM_TIS_I2C
     imply NVDIMM
     select ARM_GIC
     select ACPI

hw/tpm/Kconfig

@@ -1,3 +1,10 @@
+config TPM_TIS_I2C
+    bool
+    depends on TPM
+    select TPM_BACKEND
+    select I2C
+    select TPM_TIS
+
 config TPM_TIS_ISA
     bool
     depends on TPM && ISA_BUS

hw/tpm/meson.build

@@ -1,6 +1,7 @@
 softmmu_ss.add(when: 'CONFIG_TPM_TIS', if_true: files('tpm_tis_common.c'))
 softmmu_ss.add(when: 'CONFIG_TPM_TIS_ISA', if_true: files('tpm_tis_isa.c'))
 softmmu_ss.add(when: 'CONFIG_TPM_TIS_SYSBUS', if_true: files('tpm_tis_sysbus.c'))
+softmmu_ss.add(when: 'CONFIG_TPM_TIS_I2C', if_true: files('tpm_tis_i2c.c'))
 softmmu_ss.add(when: 'CONFIG_TPM_CRB', if_true: files('tpm_crb.c'))
 softmmu_ss.add(when: 'CONFIG_TPM_TIS', if_true: files('tpm_ppi.c'))
 softmmu_ss.add(when: 'CONFIG_TPM_CRB', if_true: files('tpm_ppi.c'))

hw/tpm/trace-events

@@ -36,3 +36,9 @@ tpm_spapr_do_crq_unknown_msg_type(uint8_t type) "Unknown message type 0x%02x"
 tpm_spapr_do_crq_unknown_crq(uint8_t raw1, uint8_t raw2) "unknown CRQ 0x%02x 0x%02x ..."
 tpm_spapr_post_load(void) "Delivering TPM response after resume"
 tpm_spapr_caught_response(uint32_t v) "Caught response to deliver after resume: %u bytes"
+
+# tpm_tis_i2c.c
+tpm_tis_i2c_recv(uint8_t data) "TPM I2C read: 0x%X"
+tpm_tis_i2c_send(uint8_t data) "TPM I2C write: 0x%X"
+tpm_tis_i2c_event(const char *event) "TPM I2C event: %s"
+tpm_tis_i2c_send_reg(const char *name, int reg) "TPM I2C write register: %s(0x%X)"

include/sysemu/tpm.h

@@ -48,6 +48,7 @@ struct TPMIfClass {
 #define TYPE_TPM_TIS_SYSBUS         "tpm-tis-device"
 #define TYPE_TPM_CRB                "tpm-crb"
 #define TYPE_TPM_SPAPR              "tpm-spapr"
+#define TYPE_TPM_TIS_I2C            "tpm-tis-i2c"
 
 #define TPM_IS_TIS_ISA(chr)                         \
     object_dynamic_cast(OBJECT(chr), TYPE_TPM_TIS_ISA)
@@ -57,6 +58,8 @@ struct TPMIfClass {
     object_dynamic_cast(OBJECT(chr), TYPE_TPM_CRB)
 #define TPM_IS_SPAPR(chr)                           \
     object_dynamic_cast(OBJECT(chr), TYPE_TPM_SPAPR)
+#define TPM_IS_TIS_I2C(chr)                      \
+    object_dynamic_cast(OBJECT(chr), TYPE_TPM_TIS_I2C)
 
 /* returns NULL unless there is exactly one TPM device */
 static inline TPMIf *tpm_find(void)