tpm: Extend common APIs to support TPM TIS I2C

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

This commit includes changes for the common code.
- Added support for the new checksum registers which are required for
  the I2C support. The checksum calculation is handled in the qemu
  common code.
- Added wrapper function for read and write data so that I2C code can
  call it without MMIO interface.

The TPM TIS I2C spec describes in the table in section "Interface Locality
Usage per Register" that the TPM_INT_ENABLE and TPM_INT_STATUS registers
must be writable for any locality even if the locality is not the active
locality. Therefore, remove the checks whether the writing locality is the
active locality for these registers.

Signed-off-by: Ninad Palsule <ninad@linux.ibm.com>
Signed-off-by: Stefan Berger <stefanb@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: 20230414220754.1191476-3-ninadpalsule@us.ibm.com

3 files changed, 72 insertions, 8 deletions

diff --git a/hw/tpm/tpm_tis.h b/hw/tpm/tpm_tis.h
index f6b5872..6f29a50 100644
--- a/hw/tpm/tpm_tis.h
+++ b/hw/tpm/tpm_tis.h
@@ -86,5 +86,8 @@ int tpm_tis_pre_save(TPMState *s);
 void tpm_tis_reset(TPMState *s);
 enum TPMVersion tpm_tis_get_tpm_version(TPMState *s);
 void tpm_tis_request_completed(TPMState *s, int ret);
+uint32_t tpm_tis_read_data(TPMState *s, hwaddr addr, unsigned size);
+void tpm_tis_write_data(TPMState *s, hwaddr addr, uint64_t val, uint32_t size);
+uint16_t tpm_tis_get_checksum(TPMState *s);
 
 #endif /* TPM_TPM_TIS_H */
diff --git a/hw/tpm/tpm_tis_common.c b/hw/tpm/tpm_tis_common.c
index 503be2a..c07c179 100644
--- a/hw/tpm/tpm_tis_common.c
+++ b/hw/tpm/tpm_tis_common.c
@@ -26,6 +26,8 @@
 #include "hw/irq.h"
 #include "hw/isa/isa.h"
 #include "qapi/error.h"
+#include "qemu/bswap.h"
+#include "qemu/crc-ccitt.h"
 #include "qemu/module.h"
 
 #include "hw/acpi/tpm.h"
@@ -448,6 +450,23 @@ static uint64_t tpm_tis_mmio_read(void *opaque, hwaddr addr,
 }
 
 /*
+ * A wrapper read function so that it can be directly called without
+ * mmio.
+ */
+uint32_t tpm_tis_read_data(TPMState *s, hwaddr addr, unsigned size)
+{
+    return tpm_tis_mmio_read(s, addr, size);
+}
+
+/*
+ * Calculate current data buffer checksum
+ */
+uint16_t tpm_tis_get_checksum(TPMState *s)
+{
+    return bswap16(crc_ccitt(0, s->buffer, s->rw_offset));
+}
+
+/*
  * Write a value to a register of the TIS interface
  * See specs pages 33-63 for description of the registers
  */
@@ -588,10 +607,6 @@ static void tpm_tis_mmio_write(void *opaque, hwaddr addr,
 
         break;
     case TPM_TIS_REG_INT_ENABLE:
-        if (s->active_locty != locty) {
-            break;
-        }
-
         s->loc[locty].inte &= mask;
         s->loc[locty].inte |= (val & (TPM_TIS_INT_ENABLED |
                                         TPM_TIS_INT_POLARITY_MASK |
@@ -601,10 +616,6 @@ static void tpm_tis_mmio_write(void *opaque, hwaddr addr,
         /* hard wired -- ignore */
         break;
     case TPM_TIS_REG_INT_STATUS:
-        if (s->active_locty != locty) {
-            break;
-        }
-
         /* clearing of interrupt flags */
         if (((val & TPM_TIS_INTERRUPTS_SUPPORTED)) &&
             (s->loc[locty].ints & TPM_TIS_INTERRUPTS_SUPPORTED)) {
@@ -767,6 +778,15 @@ static void tpm_tis_mmio_write(void *opaque, hwaddr addr,
     }
 }
 
+/*
+ * A wrapper write function so that it can be directly called without
+ * mmio.
+ */
+void tpm_tis_write_data(TPMState *s, hwaddr addr, uint64_t val, uint32_t size)
+{
+    tpm_tis_mmio_write(s, addr, val, size);
+}
+
 const MemoryRegionOps tpm_tis_memory_ops = {
     .read = tpm_tis_mmio_read,
     .write = tpm_tis_mmio_write,
diff --git a/include/hw/acpi/tpm.h b/include/hw/acpi/tpm.h
index 559ba69..579c45f 100644
--- a/include/hw/acpi/tpm.h
+++ b/include/hw/acpi/tpm.h
@@ -93,6 +93,7 @@
 #define TPM_TIS_CAP_DATA_TRANSFER_64B    (3 << 9)
 #define TPM_TIS_CAP_DATA_TRANSFER_LEGACY (0 << 9)
 #define TPM_TIS_CAP_BURST_COUNT_DYNAMIC  (0 << 8)
+#define TPM_TIS_CAP_BURST_COUNT_STATIC   (1 << 8)
 #define TPM_TIS_CAP_INTERRUPT_LOW_LEVEL  (1 << 4) /* support is mandatory */
 #define TPM_TIS_CAPABILITIES_SUPPORTED1_3 \
     (TPM_TIS_CAP_INTERRUPT_LOW_LEVEL | \
@@ -209,6 +210,46 @@ REG32(CRB_DATA_BUFFER, 0x80)
 #define TPM_PPI_FUNC_ALLOWED_USR_NOT_REQ (4 << 0)
 #define TPM_PPI_FUNC_MASK                (7 << 0)
 
+/* TPM TIS I2C registers */
+#define TPM_I2C_REG_LOC_SEL              0x00
+#define TPM_I2C_REG_ACCESS               0x04
+#define TPM_I2C_REG_INT_ENABLE           0x08
+#define TPM_I2C_REG_INT_CAPABILITY       0x14
+#define TPM_I2C_REG_STS                  0x18
+#define TPM_I2C_REG_DATA_FIFO            0x24
+#define TPM_I2C_REG_INTF_CAPABILITY      0x30
+#define TPM_I2C_REG_I2C_DEV_ADDRESS      0x38
+#define TPM_I2C_REG_DATA_CSUM_ENABLE     0x40
+#define TPM_I2C_REG_DATA_CSUM_GET        0x44
+#define TPM_I2C_REG_DID_VID              0x48
+#define TPM_I2C_REG_RID                  0x4c
+#define TPM_I2C_REG_UNKNOWN              0xff
+
+/* I2C specific interface capabilities */
+#define TPM_I2C_CAP_INTERFACE_TYPE     (0x2 << 0)       /* FIFO interface */
+#define TPM_I2C_CAP_INTERFACE_VER      (0x0 << 4)       /* TCG I2C intf 1.0 */
+#define TPM_I2C_CAP_TPM2_FAMILY        (0x1 << 7)       /* TPM 2.0 family. */
+#define TPM_I2C_CAP_DEV_ADDR_CHANGE    (0x0 << 27)      /* No dev addr chng */
+#define TPM_I2C_CAP_BURST_COUNT_STATIC (0x1 << 29)      /* Burst count static */
+#define TPM_I2C_CAP_LOCALITY_CAP       (0x1 << 25)      /* 0-5 locality */
+#define TPM_I2C_CAP_BUS_SPEED          (3   << 21)      /* std and fast mode */
+
+/*
+ * TPM_I2C_STS masks for read/writing bits from/to TIS
+ * TPM_STS mask for read bits 31:26 must be zero
+ */
+#define TPM_I2C_STS_READ_MASK          0x00ffffdd
+#define TPM_I2C_STS_WRITE_MASK         0x03000062
+
+/* Checksum enabled. */
+#define TPM_DATA_CSUM_ENABLED     0x1
+
+/*
+ * TPM_I2C_INT_ENABLE mask. Linux kernel does not support
+ * interrupts hence setting it to 0.
+ */
+#define TPM_I2C_INT_ENABLE_MASK   0x0
+
 void tpm_build_ppi_acpi(TPMIf *tpm, Aml *dev);
 
 #endif /* CONFIG_TPM */