x86: acpi: Support generation of the DBG2 table

Add an implementation of the DBG2 (Debug Port Table 2) ACPI table.
Adjust one of the header includes to be in the correct order, before
adding more.

Note that the DBG2 table is generic but the PCI UART is x86-specific at
present since it assumes an ns16550 UART. It can be generalised later
if necessary.

Signed-off-by: Simon Glass <sjg@chromium.org>

2 files changed, 52 insertions, 0 deletions

diff --git a/arch/x86/include/asm/acpi_table.h b/arch/x86/include/asm/acpi_table.h
index 7047ee6c772..1b7ff509516 100644
--- a/arch/x86/include/asm/acpi_table.h
+++ b/arch/x86/include/asm/acpi_table.h
@@ -47,6 +47,17 @@ u32 acpi_fill_csrt(u32 current);
 int acpi_write_hpet(struct acpi_ctx *ctx);
 
 /**
+ * acpi_write_dbg2_pci_uart() - Write out a DBG2 table
+ *
+ * @ctx: Current ACPI context
+ * @dev: Debug UART device to describe
+ * @access_size: Access size for UART (e.g. ACPI_ACCESS_SIZE_DWORD_ACCESS)
+ * @return 0 if OK, -ve on error
+ */
+int acpi_write_dbg2_pci_uart(struct acpi_ctx *ctx, struct udevice *dev,
+			     uint access_size);
+
+/**
  * acpi_create_gnvs() - Create a GNVS (Global Non Volatile Storage) table
  *
  * @gnvs: Table to fill in
diff --git a/arch/x86/lib/acpi_table.c b/arch/x86/lib/acpi_table.c
index 0080c96cfe7..e257c789838 100644
--- a/arch/x86/lib/acpi_table.c
+++ b/arch/x86/lib/acpi_table.c
@@ -15,6 +15,7 @@
 #include <serial.h>
 #include <version.h>
 #include <acpi/acpigen.h>
+#include <acpi/acpi_device.h>
 #include <acpi/acpi_table.h>
 #include <asm/acpi/global_nvs.h>
 #include <asm/ioapic.h>
@@ -588,3 +589,43 @@ int acpi_write_hpet(struct acpi_ctx *ctx)
 
 	return 0;
 }
+
+int acpi_write_dbg2_pci_uart(struct acpi_ctx *ctx, struct udevice *dev,
+			     uint access_size)
+{
+	struct acpi_dbg2_header *dbg2 = ctx->current;
+	char path[ACPI_PATH_MAX];
+	struct acpi_gen_regaddr address;
+	phys_addr_t addr;
+	int ret;
+
+	if (!device_active(dev)) {
+		log_info("Device not enabled\n");
+		return -EACCES;
+	}
+	/*
+	 * PCI devices don't remember their resource allocation information in
+	 * U-Boot at present. We assume that MMIO is used for the UART and that
+	 * the address space is 32 bytes: ns16550 uses 8 registers of up to
+	 * 32-bits each. This is only for debugging so it is not a big deal.
+	 */
+	addr = dm_pci_read_bar32(dev, 0);
+	printf("UART addr %lx\n", (ulong)addr);
+
+	memset(&address, '\0', sizeof(address));
+	address.space_id = ACPI_ADDRESS_SPACE_MEMORY;
+	address.addrl = (uint32_t)addr;
+	address.addrh = (uint32_t)((addr >> 32) & 0xffffffff);
+	address.access_size = access_size;
+
+	ret = acpi_device_path(dev, path, sizeof(path));
+	if (ret)
+		return log_msg_ret("path", ret);
+	acpi_create_dbg2(dbg2, ACPI_DBG2_SERIAL_PORT,
+			 ACPI_DBG2_16550_COMPATIBLE, &address, 0x1000, path);
+
+	acpi_inc_align(ctx, dbg2->header.length);
+	acpi_add_table(ctx, dbg2);
+
+	return 0;
+}