acpi: Add i2c serial bus CRS handling

This will be required for getting IPMI SSIF (SMBus interface) into
the ACPI tables.

Cc: Michael S. Tsirkin <mst@redhat.com>
Cc: Igor Mammedov <imammedo@redhat.com>
Signed-off-by: Corey Minyard <cminyard@mvista.com>

2 files changed, 58 insertions, 0 deletions

diff --git a/hw/acpi/aml-build.c b/hw/acpi/aml-build.c
index 78aee1a2f9..2c3702b882 100644
--- a/hw/acpi/aml-build.c
+++ b/hw/acpi/aml-build.c
@@ -1874,3 +1874,43 @@ build_hdr:
     build_header(linker, tbl, (void *)(tbl->data + fadt_start),
                  "FACP", tbl->len - fadt_start, f->rev, oem_id, oem_table_id);
 }
+
+/* ACPI 5.0: 6.4.3.8.2 Serial Bus Connection Descriptors */
+static Aml *aml_serial_bus_device(uint8_t serial_bus_type, uint8_t flags,
+                                  uint16_t type_flags,
+                                  uint8_t revid, uint16_t data_length,
+                                  uint16_t resource_source_len)
+{
+    Aml *var = aml_alloc();
+    uint16_t length = data_length + resource_source_len + 9;
+
+    build_append_byte(var->buf, 0x8e); /* Serial Bus Connection Descriptor */
+    build_append_int_noprefix(var->buf, length, sizeof(length));
+    build_append_byte(var->buf, 1);    /* Revision ID */
+    build_append_byte(var->buf, 0);    /* Resource Source Index */
+    build_append_byte(var->buf, serial_bus_type); /* Serial Bus Type */
+    build_append_byte(var->buf, flags); /* General Flags */
+    build_append_int_noprefix(var->buf, type_flags, /* Type Specific Flags */
+                              sizeof(type_flags));
+    build_append_byte(var->buf, revid); /* Type Specification Revision ID */
+    build_append_int_noprefix(var->buf, data_length, sizeof(data_length));
+
+    return var;
+}
+
+/* ACPI 5.0: 6.4.3.8.2.1 I2C Serial Bus Connection Resource Descriptor */
+Aml *aml_i2c_serial_bus_device(uint16_t address, const char *resource_source)
+{
+    uint16_t resource_source_len = strlen(resource_source) + 1;
+    Aml *var = aml_serial_bus_device(AML_SERIAL_BUS_TYPE_I2C, 0, 0, 1,
+                                     6, resource_source_len);
+
+    /* Connection Speed.  Just set to 100K for now, it doesn't really matter. */
+    build_append_int_noprefix(var->buf, 100000, 4);
+    build_append_int_noprefix(var->buf, address, sizeof(address));
+
+    /* This is a string, not a name, so just copy it directly in. */
+    g_array_append_vals(var->buf, resource_source, resource_source_len);
+
+    return var;
+}
diff --git a/include/hw/acpi/aml-build.h b/include/hw/acpi/aml-build.h
index 991cf05134..de4a406568 100644
--- a/include/hw/acpi/aml-build.h
+++ b/include/hw/acpi/aml-build.h
@@ -223,6 +223,23 @@ struct AcpiBuildTables {
     BIOSLinker *linker;
 } AcpiBuildTables;
 
+/*
+ * ACPI 5.0: 6.4.3.8.2 Serial Bus Connection Descriptors
+ * Serial Bus Type
+ */
+#define AML_SERIAL_BUS_TYPE_I2C  1
+#define AML_SERIAL_BUS_TYPE_SPI  2
+#define AML_SERIAL_BUS_TYPE_UART 3
+
+/*
+ * ACPI 5.0: 6.4.3.8.2 Serial Bus Connection Descriptors
+ * General Flags
+ */
+/* Slave Mode */
+#define AML_SERIAL_BUS_FLAG_MASTER_DEVICE       (1 << 0)
+/* Consumer/Producer */
+#define AML_SERIAL_BUS_FLAG_CONSUME_ONLY        (1 << 1)
+
 /**
  * init_aml_allocator:
  *
@@ -347,6 +364,7 @@ Aml *aml_qword_memory(AmlDecode dec, AmlMinFixed min_fixed,
 Aml *aml_dma(AmlDmaType typ, AmlDmaBusMaster bm, AmlTransferSize sz,
              uint8_t channel);
 Aml *aml_sleep(uint64_t msec);
+Aml *aml_i2c_serial_bus_device(uint16_t address, const char *resource_source);
 
 /* Block AML object primitives */
 Aml *aml_scope(const char *name_format, ...) GCC_FMT_ATTR(1, 2);