arch/x86/acpi: Add support for writing ACPI DBG2 table

Add a function to create an ACPI DBG2 table, which is a Microsoft
ACPI extension for providing a description of the available debug
interface on a board.

A convenience function is provided for creating a DBG2 table with
a 16550 UART based on a PCI device.

This is tested by generating a device and verifying it with iasl:

[000h 0000   4]                    Signature : "DBG2"
[004h 0004   4]                 Table Length : 00000061
[008h 0008   1]                     Revision : 00
[009h 0009   1]                     Checksum : 3B
[00Ah 0010   6]                       Oem ID : "CORE  "
[010h 0016   8]                 Oem Table ID : "COREBOOT"
[018h 0024   4]                 Oem Revision : 00000000
[01Ch 0028   4]              Asl Compiler ID : "CORE"
[020h 0032   4]        Asl Compiler Revision : 00000000

[024h 0036   4]                  Info Offset : 0000002C
[028h 0040   4]                   Info Count : 00000001

[02Ch 0044   1]                     Revision : 00
[02Dh 0045   2]                       Length : 0035
[02Fh 0047   1]               Register Count : 01
[030h 0048   2]              Namepath Length : 000F
[032h 0050   2]              Namepath Offset : 0026
[034h 0052   2]              OEM Data Length : 0000
[036h 0054   2]              OEM Data Offset : 0000
[038h 0056   2]                    Port Type : 8000
[03Ah 0058   2]                 Port Subtype : 0000
[03Ch 0060   2]                     Reserved : 0000
[03Eh 0062   2]          Base Address Offset : 0016
[040h 0064   2]          Address Size Offset : 0022

[042h 0066  12]        Base Address Register : [Generic Address Structure]
[042h 0066   1]                     Space ID : 00 [SystemMemory]
[043h 0067   1]                    Bit Width : 00
[044h 0068   1]                   Bit Offset : 00
[045h 0069   1]         Encoded Access Width : 03 [DWord Access:32]
[046h 0070   8]                      Address : 00000000FE034000

[04Eh 0078   4]                 Address Size : 00001000

[052h 0082  15]                     Namepath : "\_SB.PCI0.UAR2"

Raw Table Data: Length 97 (0x61)

  0000: 44 42 47 32 61 00 00 00 00 3B 43 4F 52 45 20 20  // DBG2a....;CORE
  0010: 43 4F 52 45 42 4F 4F 54 00 00 00 00 43 4F 52 45  // COREBOOT....CORE
  0020: 00 00 00 00 2C 00 00 00 01 00 00 00 00 35 00 01  // ....,........5..
  0030: 0F 00 26 00 00 00 00 00 00 80 00 00 00 00 16 00  // ..&.............
  0040: 22 00 00 00 00 03 00 40 03 FE 00 00 00 00 00 10  // "......@........
  0050: 00 00 5C 5F 53 42 2E 50 43 49 30 2E 55 41 52 32  // ..\_SB.PCI0.UAR2
  0060: 00                                               // .

Change-Id: I55aa3f24776b2f8aa38d7da117f422d8b8ec5479
Signed-off-by: Duncan Laurie <dlaurie@google.com>
Reviewed-on: https://review.coreboot.org/22452
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Furquan Shaikh <furquan@google.com>

2 files changed, 156 insertions, 0 deletions

diff --git a/src/arch/x86/acpi.c b/src/arch/x86/acpi.c
index 02884c494c..56f64084e8 100644
--- a/src/arch/x86/acpi.c
+++ b/src/arch/x86/acpi.c
@@ -658,6 +658,118 @@ unsigned long acpi_write_hpet(device_t device, unsigned long current,
 	return current;
 }
 
+void acpi_create_dbg2(acpi_dbg2_header_t *dbg2,
+		      int port_type, int port_subtype,
+		      acpi_addr_t *address, uint32_t address_size,
+		      const char *device_path)
+{
+	uintptr_t current;
+	acpi_dbg2_device_t *device;
+	uint32_t *dbg2_addr_size;
+	acpi_header_t *header;
+	size_t path_len;
+	const char *path;
+	char *namespace;
+
+	/* Fill out header fields. */
+	current = (uintptr_t)dbg2;
+	memset(dbg2, 0, sizeof(acpi_dbg2_header_t));
+	header = &(dbg2->header);
+	header->revision = 0;
+	memcpy(header->signature, "DBG2", 4);
+	memcpy(header->oem_id, OEM_ID, 6);
+	memcpy(header->oem_table_id, ACPI_TABLE_CREATOR, 8);
+	memcpy(header->asl_compiler_id, ASLC, 4);
+
+	/* One debug device defined */
+	dbg2->devices_offset = sizeof(acpi_dbg2_header_t);
+	dbg2->devices_count = 1;
+	current += sizeof(acpi_dbg2_header_t);
+
+	/* Device comes after the header */
+	device = (acpi_dbg2_device_t *)current;
+	memset(device, 0, sizeof(acpi_dbg2_device_t));
+	current += sizeof(acpi_dbg2_device_t);
+
+	device->revision = 0;
+	device->address_count = 1;
+	device->port_type = port_type;
+	device->port_subtype = port_subtype;
+
+	/* Base Address comes after device structure */
+	memcpy((void *)current, address, sizeof(acpi_addr_t));
+	device->base_address_offset = current - (uintptr_t)device;
+	current += sizeof(acpi_addr_t);
+
+	/* Address Size comes after address structure */
+	dbg2_addr_size = (uint32_t *)current;
+	device->address_size_offset = current - (uintptr_t)device;
+	*dbg2_addr_size = address_size;
+	current += sizeof(uint32_t);
+
+	/* Namespace string comes last, use '.' if not provided */
+	path = device_path ? : ".";
+	/* Namespace string length includes NULL terminator */
+	path_len = strlen(path) + 1;
+	namespace = (char *)current;
+	device->namespace_string_length = path_len;
+	device->namespace_string_offset = current - (uintptr_t)device;
+	strncpy(namespace, path, path_len);
+	current += path_len;
+
+	/* Update structure lengths and checksum */
+	device->length = current - (uintptr_t)device;
+	header->length = current - (uintptr_t)dbg2;
+	header->checksum = acpi_checksum((uint8_t *)dbg2, header->length);
+}
+
+unsigned long acpi_write_dbg2_pci_uart(acpi_rsdp_t *rsdp, unsigned long current,
+				       struct device *dev, uint8_t access_size)
+{
+	acpi_dbg2_header_t *dbg2 = (acpi_dbg2_header_t *)current;
+	struct resource *res;
+	acpi_addr_t address;
+
+	if (!dev) {
+		printk(BIOS_ERR, "%s: Device not found\n", __func__);
+		return current;
+	}
+	res = find_resource(dev, PCI_BASE_ADDRESS_0);
+	if (!res) {
+		printk(BIOS_ERR, "%s: Unable to find resource for %s\n",
+		       __func__, dev_path(dev));
+		return current;
+	}
+
+	memset(&address, 0, sizeof(address));
+	if (res->flags & IORESOURCE_IO)
+		address.space_id = ACPI_ADDRESS_SPACE_IO;
+	else if (res->flags & IORESOURCE_MEM)
+		address.space_id = ACPI_ADDRESS_SPACE_MEMORY;
+	else {
+		printk(BIOS_ERR, "%s: Unknown address space type\n", __func__);
+		return current;
+	}
+
+	address.addrl = (uint32_t)res->base;
+	address.addrh = (uint32_t)((res->base >> 32) & 0xffffffff);
+	address.access_size = access_size;
+
+	acpi_create_dbg2(dbg2,
+			 ACPI_DBG2_PORT_SERIAL,
+			 ACPI_DBG2_PORT_SERIAL_16550,
+			 &address, res->size,
+			 acpi_device_path(dev));
+
+	if (dbg2->header.length) {
+		current += dbg2->header.length;
+		current = acpi_align_current(current);
+		acpi_add_table(rsdp, dbg2);
+	}
+
+	return current;
+}
+
 void acpi_create_facs(acpi_facs_t *facs)
 {
 	memset((void *)facs, 0, sizeof(acpi_facs_t));
diff --git a/src/arch/x86/include/arch/acpi.h b/src/arch/x86/include/arch/acpi.h
index 1b239912d7..5418420342 100644
--- a/src/arch/x86/include/arch/acpi.h
+++ b/src/arch/x86/include/arch/acpi.h
@@ -404,6 +404,43 @@ typedef struct acpi_madt_irqoverride {
 	u16 flags;			/* MPS INTI flags */
 } __packed acpi_madt_irqoverride_t;
 
+#define ACPI_DBG2_PORT_SERIAL			0x8000
+#define  ACPI_DBG2_PORT_SERIAL_16550		0x0000
+#define  ACPI_DBG2_PORT_SERIAL_16550_DBGP	0x0001
+#define  ACPI_DBG2_PORT_SERIAL_ARM_PL011	0x0003
+#define  ACPI_DBG2_PORT_SERIAL_ARM_SBSA		0x000e
+#define  ACPI_DBG2_PORT_SERIAL_ARM_DDC		0x000f
+#define  ACPI_DBG2_PORT_SERIAL_BCM2835		0x0010
+#define ACPI_DBG2_PORT_IEEE1394			0x8001
+#define  ACPI_DBG2_PORT_IEEE1394_STANDARD	0x0000
+#define ACPI_DBG2_PORT_USB			0x8002
+#define  ACPI_DBG2_PORT_USB_XHCI		0x0000
+#define  ACPI_DBG2_PORT_USB_EHCI		0x0001
+#define ACPI_DBG2_PORT_NET			0x8003
+
+/* DBG2: Microsoft Debug Port Table 2 header */
+typedef struct acpi_dbg2_header {
+	struct acpi_table_header header;
+	uint32_t devices_offset;
+	uint32_t devices_count;
+} __attribute__ ((packed)) acpi_dbg2_header_t;
+
+/* DBG2: Microsoft Debug Port Table 2 device entry */
+typedef struct acpi_dbg2_device {
+	uint8_t  revision;
+	uint16_t length;
+	uint8_t  address_count;
+	uint16_t namespace_string_length;
+	uint16_t namespace_string_offset;
+	uint16_t oem_data_length;
+	uint16_t oem_data_offset;
+	uint16_t port_type;
+	uint16_t port_subtype;
+	uint8_t  reserved[2];
+	uint16_t base_address_offset;
+	uint16_t address_size_offset;
+} __attribute__ ((packed)) acpi_dbg2_device_t;
+
 /* FADT (Fixed ACPI Description Table) */
 typedef struct acpi_fadt {
 	struct acpi_table_header header;
@@ -667,6 +704,13 @@ void acpi_create_mcfg(acpi_mcfg_t *mcfg);
 
 void acpi_create_facs(acpi_facs_t *facs);
 
+void acpi_create_dbg2(acpi_dbg2_header_t *dbg2_header,
+		      int port_type, int port_subtype,
+		      acpi_addr_t *address, uint32_t address_size,
+		      const char *device_path);
+
+unsigned long acpi_write_dbg2_pci_uart(acpi_rsdp_t *rsdp, unsigned long current,
+				       struct device *dev, uint8_t access_size);
 void acpi_create_dmar(acpi_dmar_t *dmar, enum dmar_flags flags,
 		      unsigned long (*acpi_fill_dmar)(unsigned long));
 unsigned long acpi_create_dmar_drhd(unsigned long current, u8 flags,