本文主要是介绍qemu中建立spcr的acpi table，希望对大家解决编程问题提供一定的参考价值，需要的开发者们随着小编来一起学习吧！
在qemu/hw/arm/virt-apci-build.c 中会创建传给guest的acpi table。这里我们以组建spcr为例
virt_acpi_build->build_spcr
static void
build_spcr(GArray *table_data, BIOSLinker *linker, VirtMachineState *vms)
{AcpiSerialPortConsoleRedirection *spcr;const MemMapEntry *uart_memmap = &vms->memmap[VIRT_UART];int irq = vms->irqmap[VIRT_UART] + ARM_SPI_BASE;int spcr_start = table_data->len;
#得到spcr的首地址指针spcr = acpi_data_push(table_data, sizeof(*spcr));
#下面就是spcr的个个成员变量的赋值spcr->interface_type = 0x3; /* ARM PL011 UART */spcr->base_address.space_id = AML_SYSTEM_MEMORY;spcr->base_address.bit_width = 8;spcr->base_address.bit_offset = 0;spcr->base_address.access_width = 1;spcr->base_address.address = cpu_to_le64(uart_memmap->base);spcr->interrupt_types = (1 << 3); /* Bit[3] ARMH GIC interrupt */spcr->gsi = cpu_to_le32(irq); /* Global System Interrupt */spcr->baud = 3; /* Baud Rate: 3 = 9600 */spcr->parity = 0; /* No Parity */spcr->stopbits = 1; /* 1 Stop bit */spcr->flowctrl = (1 << 1); /* Bit[1] = RTS/CTS hardware flow control */spcr->term_type = 0; /* Terminal Type: 0 = VT100 */spcr->pci_device_id = 0xffff; /* PCI Device ID: not a PCI device */spcr->pci_vendor_id = 0xffff; /* PCI Vendor ID: not a PCI device */
#将创建spcr table 的头信息build_header(linker, table_data, (void *)(table_data->data + spcr_start),"SPCR", table_data->len - spcr_start, 2, NULL, NULL);
}build_header(BIOSLinker *linker, GArray *table_data,AcpiTableHeader *h, const char *sig, int len, uint8_t rev,const char *oem_id, const char *oem_table_id)
{unsigned tbl_offset = (char *)h - table_data->data;unsigned checksum_offset = (char *)&h->checksum - table_data->data;memcpy(&h->signature, sig, 4);h->length = cpu_to_le32(len);h->revision = rev;
#scpr是否包括oem idif (oem_id) {strncpy((char *)h->oem_id, oem_id, sizeof h->oem_id);} else {memcpy(h->oem_id, ACPI_BUILD_APPNAME6, 6);}if (oem_table_id) {strncpy((char *)h->oem_table_id, oem_table_id, sizeof(h->oem_table_id));} else {memcpy(h->oem_table_id, ACPI_BUILD_APPNAME4, 4);memcpy(h->oem_table_id + 4, sig, 4);}h->oem_revision = cpu_to_le32(1);memcpy(h->asl_compiler_id, ACPI_BUILD_APPNAME4, 4);h->asl_compiler_revision = cpu_to_le32(1);/* Checksum to be filled in by Guest linker */
ask guest to add checksum of ACPI * table in the specified file at the specified offset.
#在表中加入check sum信息，这段组建spcr table的逻辑和bios中的类似bios_linker_loader_add_checksum(linker, ACPI_BUILD_TABLE_FILE,tbl_offset, len, checksum_offset);
}
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