From: Michael Brown <mcb30@ipxe.org>
Date: Wed, 5 Nov 2025 14:07:27 +0000 (+0000)
Subject: [acpi] Add acpi_ioremap() to map an ACPI-described address
X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=8fd5e277275141866feea80870f8b94b23a0e82d;p=thirdparty%2Fipxe.git

[acpi] Add acpi_ioremap() to map an ACPI-described address

An ACPI Generic Address Structure (GAS) may be used to describe the
location of a peripheral such as an early boot console.  Add the
relevant definitions and provide acpi_ioremap() as a helper function
to map a region described using this structure.

Signed-off-by: Michael Brown <mcb30@ipxe.org>
---

diff --git a/src/core/acpi.c b/src/core/acpi.c
index 6c5d1e079..fa8ed34ff 100644
--- a/src/core/acpi.c
+++ b/src/core/acpi.c
@@ -27,6 +27,7 @@ FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
 #include <errno.h>
 #include <byteswap.h>
 #include <ipxe/uaccess.h>
+#include <ipxe/iomap.h>
 #include <ipxe/acpi.h>
 #include <ipxe/interface.h>
 
@@ -258,6 +259,24 @@ int acpi_extract ( uint32_t signature, void *data,
 	return -ENOENT;
 }
 
+/**
+ * Map an ACPI generic address
+ *
+ * @v address		Generic address
+ * @v len		Length of region
+ * @ret io_addr		I/O address, or NULL on error
+ */
+void * acpi_ioremap ( struct acpi_address *address, size_t len ) {
+	physaddr_t base = le64_to_cpu ( address->address );
+
+	switch ( address->type ) {
+	case ACPI_ADDRESS_TYPE_MEM:
+		return ioremap ( base, len );
+	default:
+		return NULL;
+	}
+}
+
 /******************************************************************************
  *
  * Descriptors
diff --git a/src/include/ipxe/acpi.h b/src/include/ipxe/acpi.h
index 40a44cffc..5e9fb5eba 100644
--- a/src/include/ipxe/acpi.h
+++ b/src/include/ipxe/acpi.h
@@ -18,6 +18,29 @@ FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
 #include <ipxe/api.h>
 #include <config/general.h>
 
+/** An ACPI generic address structure */
+struct acpi_address {
+	/** Address space type */
+	uint8_t type;
+	/** Register bit width */
+	uint8_t width;
+	/** Register bit offset */
+	uint8_t offset;
+	/** Access size */
+	uint8_t access;
+	/** Address */
+	uint64_t address;
+} __attribute__ (( packed ));
+
+/** A memory address space type */
+#define ACPI_ADDRESS_TYPE_MEM 0x00
+
+/** An I/O address space type */
+#define ACPI_ADDRESS_TYPE_IO 0x01
+
+/** A bus number address space type */
+#define ACPI_ADDRESS_TYPE_BUS 0x02
+
 /** An ACPI small resource descriptor header */
 struct acpi_small_resource {
 	/** Tag byte */
@@ -74,12 +97,6 @@ struct acpi_qword_address_space_resource {
 	uint64_t len;
 } __attribute__ (( packed ));
 
-/** A memory address space type */
-#define ACPI_ADDRESS_TYPE_MEM 0x00
-
-/** A bus number address space type */
-#define ACPI_ADDRESS_TYPE_BUS 0x02
-
 /** An ACPI resource descriptor */
 union acpi_resource {
 	/** Tag byte */
@@ -397,6 +414,7 @@ extern int acpi_extract ( uint32_t signature, void *data,
 			  int ( * extract ) ( const struct acpi_header *zsdt,
 					      size_t len, size_t offset,
 					      void *data ) );
+extern void * acpi_ioremap ( struct acpi_address *address, size_t len );
 extern void acpi_add ( struct acpi_descriptor *desc );
 extern void acpi_del ( struct acpi_descriptor *desc );
 extern int acpi_install ( int ( * install ) ( struct acpi_header *acpi ) );