kernel: acpi: Add uACPI portexpt

See https://github.com/uACPI/uACPI/

Signed-off-by: Ian Moffett <ian@osmora.org>

1 files changed, 1056 insertions, 0 deletions

diff --git a/sys/dev/acpi/uacpi/opregion.c b/sys/dev/acpi/uacpi/opregion.c
new file mode 100644
index 0000000..ec0bc37
--- /dev/null
+++ b/sys/dev/acpi/uacpi/opregion.c
@@ -0,0 +1,1056 @@
+#include <uacpi/kernel_api.h>
+
+#include <uacpi/internal/opregion.h>
+#include <uacpi/internal/namespace.h>
+#include <uacpi/internal/stdlib.h>
+#include <uacpi/internal/log.h>
+#include <uacpi/internal/utilities.h>
+#include <uacpi/internal/mutex.h>
+#include <uacpi/internal/interpreter.h>
+
+#ifndef UACPI_BAREBONES_MODE
+
+struct uacpi_recursive_lock g_opregion_lock;
+
+uacpi_status uacpi_initialize_opregion(void)
+{
+    return uacpi_recursive_lock_init(&g_opregion_lock);
+}
+
+void uacpi_deinitialize_opregion(void)
+{
+    uacpi_recursive_lock_deinit(&g_opregion_lock);
+}
+
+void uacpi_trace_region_error(
+    uacpi_namespace_node *node, uacpi_char *message, uacpi_status ret
+)
+{
+    const uacpi_char *path, *space_string = "<unknown>";
+    uacpi_object *obj;
+
+    path = uacpi_namespace_node_generate_absolute_path(node);
+
+    obj = uacpi_namespace_node_get_object_typed(
+        node, UACPI_OBJECT_OPERATION_REGION_BIT
+    );
+    if (uacpi_likely(obj != UACPI_NULL))
+        space_string = uacpi_address_space_to_string(obj->op_region->space);
+
+    uacpi_error(
+        "%s (%s) operation region %s: %s\n",
+        message, space_string, path, uacpi_status_to_string(ret)
+    );
+    uacpi_free_dynamic_string(path);
+}
+
+static void trace_region_io(
+    uacpi_field_unit *field, uacpi_address_space space, uacpi_u64 offset,
+    uacpi_region_op op, union uacpi_opregion_io_data data
+)
+{
+    const uacpi_char *path;
+    const uacpi_char *type_str;
+
+    if (!uacpi_should_log(UACPI_LOG_TRACE))
+        return;
+
+    switch (op) {
+    case UACPI_REGION_OP_READ:
+        type_str = "read from";
+        break;
+    case UACPI_REGION_OP_WRITE:
+        type_str = "write to";
+        break;
+    default:
+        type_str = "<INVALID-OP>";
+    }
+
+    path = uacpi_namespace_node_generate_absolute_path(field->region);
+
+    switch (space) {
+    case UACPI_ADDRESS_SPACE_IPMI:
+    case UACPI_ADDRESS_SPACE_PRM:
+    case UACPI_ADDRESS_SPACE_FFIXEDHW:
+        uacpi_trace(
+            "write-then-read from [%s] %s[0x%016"UACPI_PRIX64"] = "
+            "<buffer of %zu bytes>\n", path,
+            uacpi_address_space_to_string(space),
+            UACPI_FMT64(offset), data.buffer.length
+        );
+        break;
+    case UACPI_ADDRESS_SPACE_SMBUS:
+    case UACPI_ADDRESS_SPACE_GENERIC_SERIAL_BUS:
+        uacpi_trace(
+            "%s [%s] %s[0x%016"UACPI_PRIX64"] = "
+            "<buffer of %zu bytes>\n", type_str, path,
+            uacpi_address_space_to_string(space),
+            UACPI_FMT64(offset), data.buffer.length
+        );
+        break;
+    case UACPI_ADDRESS_SPACE_GENERAL_PURPOSE_IO:
+        uacpi_trace(
+            "%s [%s] %s pins[%u..%u] = 0x%"UACPI_PRIX64"\n",
+            type_str, path, uacpi_address_space_to_string(space),
+            field->pin_offset, (field->pin_offset + field->bit_length) - 1,
+            UACPI_FMT64(*data.integer)
+        );
+        break;
+    default:
+        uacpi_trace(
+            "%s [%s] (%d bytes) %s[0x%016"UACPI_PRIX64"] = 0x%"UACPI_PRIX64"\n",
+            type_str, path, field->access_width_bytes,
+            uacpi_address_space_to_string(space),
+            UACPI_FMT64(offset), UACPI_FMT64(*data.integer)
+        );
+        break;
+    }
+
+    uacpi_free_dynamic_string(path);
+}
+
+static uacpi_bool space_needs_reg(enum uacpi_address_space space)
+{
+    if (space == UACPI_ADDRESS_SPACE_SYSTEM_MEMORY ||
+        space == UACPI_ADDRESS_SPACE_SYSTEM_IO ||
+        space == UACPI_ADDRESS_SPACE_TABLE_DATA)
+        return UACPI_FALSE;
+
+    return UACPI_TRUE;
+}
+
+static uacpi_status region_run_reg(
+    uacpi_namespace_node *node, uacpi_u8 connection_code
+)
+{
+    uacpi_status ret;
+    uacpi_namespace_node *reg_node;
+    uacpi_object_array method_args;
+    uacpi_object *reg_obj, *args[2];
+
+    ret = uacpi_namespace_node_resolve(
+        node->parent, "_REG", UACPI_SHOULD_LOCK_NO,
+        UACPI_MAY_SEARCH_ABOVE_PARENT_NO, UACPI_PERMANENT_ONLY_NO, &reg_node
+    );
+    if (uacpi_unlikely_error(ret))
+        return ret;
+
+    reg_obj = uacpi_namespace_node_get_object_typed(
+        reg_node, UACPI_OBJECT_METHOD_BIT
+    );
+    if (uacpi_unlikely(reg_obj == UACPI_NULL))
+        return UACPI_STATUS_OK;
+
+    args[0] = uacpi_create_object(UACPI_OBJECT_INTEGER);
+    if (uacpi_unlikely(args[0] == UACPI_NULL))
+        return UACPI_STATUS_OUT_OF_MEMORY;
+
+    args[1] = uacpi_create_object(UACPI_OBJECT_INTEGER);
+    if (uacpi_unlikely(args[1] == UACPI_NULL)) {
+        uacpi_object_unref(args[0]);
+        return UACPI_STATUS_OUT_OF_MEMORY;
+    }
+
+    args[0]->integer = uacpi_namespace_node_get_object(node)->op_region->space;
+    args[1]->integer = connection_code;
+    method_args.objects = args;
+    method_args.count = 2;
+
+    ret = uacpi_execute_control_method(
+        reg_node, reg_obj->method, &method_args, UACPI_NULL
+    );
+    if (uacpi_unlikely_error(ret))
+        uacpi_trace_region_error(node, "error during _REG execution for", ret);
+
+    uacpi_object_unref(args[0]);
+    uacpi_object_unref(args[1]);
+    return ret;
+}
+
+uacpi_address_space_handlers *uacpi_node_get_address_space_handlers(
+    uacpi_namespace_node *node
+)
+{
+    uacpi_object *object;
+
+    if (node == uacpi_namespace_root())
+        return g_uacpi_rt_ctx.root_object->address_space_handlers;
+
+    object = uacpi_namespace_node_get_object(node);
+    if (uacpi_unlikely(object == UACPI_NULL))
+        return UACPI_NULL;
+
+    switch (object->type) {
+    case UACPI_OBJECT_DEVICE:
+    case UACPI_OBJECT_PROCESSOR:
+    case UACPI_OBJECT_THERMAL_ZONE:
+        return object->address_space_handlers;
+    default:
+        return UACPI_NULL;
+    }
+}
+
+static uacpi_address_space_handler *find_handler(
+    uacpi_address_space_handlers *handlers,
+    enum uacpi_address_space space
+)
+{
+    uacpi_address_space_handler *handler = handlers->head;
+
+    while (handler) {
+        if (handler->space == space)
+            return handler;
+
+        handler = handler->next;
+    }
+
+    return UACPI_NULL;
+}
+
+static uacpi_operation_region *find_previous_region_link(
+    uacpi_operation_region *region
+)
+{
+    uacpi_address_space_handler *handler = region->handler;
+    uacpi_operation_region *parent = handler->regions;
+
+    if (parent == region)
+        // This is the last attached region, it has no previous link
+        return region;
+
+    while (parent->next != region) {
+        parent = parent->next;
+
+        if (uacpi_unlikely(parent == UACPI_NULL))
+            return UACPI_NULL;
+    }
+
+    return parent;
+}
+
+uacpi_status uacpi_opregion_attach(uacpi_namespace_node *node)
+{
+    uacpi_object *obj;
+    uacpi_operation_region *region;
+    uacpi_address_space_handler *handler;
+    uacpi_status ret;
+    uacpi_region_attach_data attach_data = { 0 };
+
+    if (uacpi_namespace_node_is_dangling(node))
+        return UACPI_STATUS_NAMESPACE_NODE_DANGLING;
+
+    obj = uacpi_namespace_node_get_object_typed(
+        node, UACPI_OBJECT_OPERATION_REGION_BIT
+    );
+    if (uacpi_unlikely(obj == UACPI_NULL))
+        return UACPI_STATUS_INVALID_ARGUMENT;
+
+    region = obj->op_region;
+
+    if (region->handler == UACPI_NULL)
+        return UACPI_STATUS_NO_HANDLER;
+    if (region->state_flags & UACPI_OP_REGION_STATE_ATTACHED)
+        return UACPI_STATUS_OK;
+
+    handler = region->handler;
+    attach_data.region_node = node;
+
+    switch (region->space) {
+    case UACPI_ADDRESS_SPACE_PCC:
+        if (region->length) {
+            region->internal_buffer = uacpi_kernel_alloc_zeroed(region->length);
+            if (uacpi_unlikely(region->internal_buffer == UACPI_NULL))
+                return UACPI_STATUS_OUT_OF_MEMORY;
+        }
+
+        attach_data.pcc_info.buffer.bytes = region->internal_buffer;
+        attach_data.pcc_info.buffer.length = region->length;
+        attach_data.pcc_info.subspace_id = region->offset;
+        break;
+    case UACPI_ADDRESS_SPACE_GENERAL_PURPOSE_IO:
+        attach_data.gpio_info.num_pins = region->length;
+        break;
+    default:
+        attach_data.generic_info.base = region->offset;
+        attach_data.generic_info.length = region->length;
+        break;
+    }
+
+    attach_data.handler_context = handler->user_context;
+
+    uacpi_object_ref(obj);
+    uacpi_namespace_write_unlock();
+    ret = handler->callback(UACPI_REGION_OP_ATTACH, &attach_data);
+    uacpi_namespace_write_lock();
+
+    if (uacpi_unlikely_error(ret)) {
+        uacpi_object_unref(obj);
+        return ret;
+    }
+
+    region->state_flags |= UACPI_OP_REGION_STATE_ATTACHED;
+    region->user_context = attach_data.out_region_context;
+    uacpi_object_unref(obj);
+    return ret;
+}
+
+static void region_install_handler(
+    uacpi_namespace_node *node, uacpi_address_space_handler *handler
+)
+{
+    uacpi_operation_region *region;
+
+    region = uacpi_namespace_node_get_object(node)->op_region;
+    region->handler = handler;
+    uacpi_shareable_ref(handler);
+
+    region->next = handler->regions;
+    handler->regions = region;
+}
+
+enum unreg {
+    UNREG_NO = 0,
+    UNREG_YES,
+};
+
+static void region_uninstall_handler(
+    uacpi_namespace_node *node, enum unreg unreg
+)
+{
+    uacpi_status ret;
+    uacpi_object *obj;
+    uacpi_address_space_handler *handler;
+    uacpi_operation_region *region, *link;
+
+    obj = uacpi_namespace_node_get_object_typed(
+        node, UACPI_OBJECT_OPERATION_REGION_BIT
+    );
+    if (uacpi_unlikely(obj == UACPI_NULL))
+        return;
+
+    region = obj->op_region;
+
+    handler = region->handler;
+    if (handler == UACPI_NULL)
+        return;
+
+    link = find_previous_region_link(region);
+    if (uacpi_unlikely(link == UACPI_NULL)) {
+        uacpi_error("operation region @%p not in the handler@%p list(?)\n",
+                    region, handler);
+        goto out;
+    } else if (link == region) {
+        link = link->next;
+        handler->regions = link;
+    } else {
+        link->next = region->next;
+    }
+
+out:
+    if (region->state_flags & UACPI_OP_REGION_STATE_ATTACHED) {
+        uacpi_region_detach_data detach_data = { 0 };
+
+        detach_data.region_node = node;
+        detach_data.region_context = region->user_context;
+        detach_data.handler_context = handler->user_context;
+
+        uacpi_shareable_ref(node);
+        uacpi_namespace_write_unlock();
+
+        ret = handler->callback(UACPI_REGION_OP_DETACH, &detach_data);
+
+        uacpi_namespace_write_lock();
+        uacpi_namespace_node_unref(node);
+
+        if (uacpi_unlikely_error(ret)) {
+            uacpi_trace_region_error(
+                node, "error during handler detach for", ret
+            );
+        }
+    }
+
+    if ((region->state_flags & UACPI_OP_REGION_STATE_REG_EXECUTED) &&
+        unreg == UNREG_YES) {
+        region_run_reg(node, ACPI_REG_DISCONNECT);
+        region->state_flags &= ~UACPI_OP_REGION_STATE_REG_EXECUTED;
+    }
+
+    uacpi_address_space_handler_unref(region->handler);
+    region->handler = UACPI_NULL;
+    region->state_flags &= ~UACPI_OP_REGION_STATE_ATTACHED;
+}
+
+static uacpi_status upgrade_to_opregion_lock(void)
+{
+    uacpi_status ret;
+
+    /*
+     * Drop the namespace lock, and reacquire it after the opregion lock
+     * so we keep the ordering with user API.
+     */
+    uacpi_namespace_write_unlock();
+
+    ret = uacpi_recursive_lock_acquire(&g_opregion_lock);
+    uacpi_namespace_write_lock();
+    return ret;
+}
+
+void uacpi_opregion_uninstall_handler(uacpi_namespace_node *node)
+{
+    if (uacpi_unlikely_error(upgrade_to_opregion_lock()))
+        return;
+
+    region_uninstall_handler(node, UNREG_YES);
+
+    uacpi_recursive_lock_release(&g_opregion_lock);
+}
+
+uacpi_bool uacpi_address_space_handler_is_default(
+    uacpi_address_space_handler *handler
+)
+{
+    return handler->flags & UACPI_ADDRESS_SPACE_HANDLER_DEFAULT;
+}
+
+enum opregion_iter_action {
+    OPREGION_ITER_ACTION_UNINSTALL,
+    OPREGION_ITER_ACTION_INSTALL,
+};
+
+struct opregion_iter_ctx {
+    enum opregion_iter_action action;
+    uacpi_address_space_handler *handler;
+};
+
+static uacpi_iteration_decision do_install_or_uninstall_handler(
+    uacpi_handle opaque, uacpi_namespace_node *node, uacpi_u32 depth
+)
+{
+    struct opregion_iter_ctx *ctx = opaque;
+    uacpi_address_space_handlers *handlers;
+    uacpi_object *object;
+
+    UACPI_UNUSED(depth);
+
+    object = uacpi_namespace_node_get_object(node);
+    if (object->type == UACPI_OBJECT_OPERATION_REGION) {
+        uacpi_operation_region *region = object->op_region;
+
+        if (region->space != ctx->handler->space)
+            return UACPI_ITERATION_DECISION_CONTINUE;
+
+        if (ctx->action == OPREGION_ITER_ACTION_INSTALL) {
+            if (region->handler)
+                region_uninstall_handler(node, UNREG_NO);
+
+            region_install_handler(node, ctx->handler);
+        } else {
+            if (uacpi_unlikely(region->handler != ctx->handler)) {
+                uacpi_trace_region_error(
+                    node, "handler mismatch for",
+                    UACPI_STATUS_INTERNAL_ERROR
+                );
+                return UACPI_ITERATION_DECISION_CONTINUE;
+            }
+
+            region_uninstall_handler(node, UNREG_NO);
+        }
+
+        return UACPI_ITERATION_DECISION_CONTINUE;
+    }
+
+    handlers = uacpi_node_get_address_space_handlers(node);
+    if (handlers == UACPI_NULL)
+        return UACPI_ITERATION_DECISION_CONTINUE;
+
+    // Device already has a handler for this space installed
+    if (find_handler(handlers, ctx->handler->space) != UACPI_NULL)
+        return UACPI_ITERATION_DECISION_NEXT_PEER;
+
+    return UACPI_ITERATION_DECISION_CONTINUE;
+}
+
+struct reg_run_ctx {
+    uacpi_u8 space;
+    uacpi_u8 connection_code;
+    uacpi_size reg_executed;
+    uacpi_size reg_errors;
+};
+
+static uacpi_iteration_decision do_run_reg(
+    void *opaque, uacpi_namespace_node *node, uacpi_u32 depth
+)
+{
+    struct reg_run_ctx *ctx = opaque;
+    uacpi_operation_region *region;
+    uacpi_status ret;
+    uacpi_bool was_regged;
+
+    UACPI_UNUSED(depth);
+
+    region = uacpi_namespace_node_get_object(node)->op_region;
+
+    if (region->space != ctx->space)
+        return UACPI_ITERATION_DECISION_CONTINUE;
+
+    was_regged = region->state_flags & UACPI_OP_REGION_STATE_REG_EXECUTED;
+    if (was_regged == (ctx->connection_code == ACPI_REG_CONNECT))
+        return UACPI_ITERATION_DECISION_CONTINUE;
+
+    ret = region_run_reg(node, ctx->connection_code);
+    if (ctx->connection_code == ACPI_REG_DISCONNECT)
+        region->state_flags &= ~UACPI_OP_REGION_STATE_REG_EXECUTED;
+
+    if (ret == UACPI_STATUS_NOT_FOUND)
+        return UACPI_ITERATION_DECISION_CONTINUE;
+
+    if (ctx->connection_code == ACPI_REG_CONNECT)
+        region->state_flags |= UACPI_OP_REGION_STATE_REG_EXECUTED;
+
+    ctx->reg_executed++;
+
+    if (uacpi_unlikely_error(ret)) {
+        ctx->reg_errors++;
+        return UACPI_ITERATION_DECISION_CONTINUE;
+    }
+
+    return UACPI_ITERATION_DECISION_CONTINUE;
+}
+
+static uacpi_status reg_or_unreg_all_opregions(
+    uacpi_namespace_node *device_node, enum uacpi_address_space space,
+    uacpi_u8 connection_code
+)
+{
+    uacpi_address_space_handlers *handlers;
+    uacpi_bool is_connect;
+    enum uacpi_permanent_only perm_only;
+    struct reg_run_ctx ctx = { 0 };
+
+    ctx.space = space;
+    ctx.connection_code = connection_code;
+
+    handlers = uacpi_node_get_address_space_handlers(device_node);
+    if (uacpi_unlikely(handlers == UACPI_NULL))
+        return UACPI_STATUS_INVALID_ARGUMENT;
+
+    is_connect = connection_code == ACPI_REG_CONNECT;
+    if (uacpi_unlikely(is_connect &&
+                       find_handler(handlers, space) == UACPI_NULL))
+        return UACPI_STATUS_NO_HANDLER;
+
+    /*
+     * We want to unreg non-permanent opregions as well, however,
+     * registering them is handled separately and should not be
+     * done by us.
+     */
+    perm_only = is_connect ? UACPI_PERMANENT_ONLY_YES : UACPI_PERMANENT_ONLY_NO;
+
+    uacpi_namespace_do_for_each_child(
+        device_node, do_run_reg, UACPI_NULL,
+        UACPI_OBJECT_OPERATION_REGION_BIT, UACPI_MAX_DEPTH_ANY,
+        UACPI_SHOULD_LOCK_NO, perm_only, &ctx
+    );
+
+    uacpi_trace(
+        "%sactivated all '%s' opregions controlled by '%.4s', "
+        "%zu _REG() calls (%zu errors)\n",
+        connection_code == ACPI_REG_CONNECT ? "" : "de",
+        uacpi_address_space_to_string(space),
+        device_node->name.text, ctx.reg_executed, ctx.reg_errors
+    );
+    return UACPI_STATUS_OK;
+}
+
+static uacpi_address_space_handlers *extract_handlers(
+    uacpi_namespace_node *node
+)
+{
+    uacpi_object *handlers_obj;
+
+    if (node == uacpi_namespace_root())
+        return g_uacpi_rt_ctx.root_object->address_space_handlers;
+
+    handlers_obj = uacpi_namespace_node_get_object_typed(
+        node,
+        UACPI_OBJECT_DEVICE_BIT | UACPI_OBJECT_THERMAL_ZONE_BIT |
+        UACPI_OBJECT_PROCESSOR_BIT
+    );
+    if (uacpi_unlikely(handlers_obj == UACPI_NULL))
+        return UACPI_NULL;
+
+    return handlers_obj->address_space_handlers;
+}
+
+uacpi_status uacpi_reg_all_opregions(
+    uacpi_namespace_node *device_node,
+    enum uacpi_address_space space
+)
+{
+    uacpi_status ret;
+
+    UACPI_ENSURE_INIT_LEVEL_AT_LEAST(UACPI_INIT_LEVEL_NAMESPACE_LOADED);
+
+    if (!space_needs_reg(space))
+        return UACPI_STATUS_OK;
+
+    ret = uacpi_recursive_lock_acquire(&g_opregion_lock);
+    if (uacpi_unlikely_error(ret))
+        return ret;
+
+    ret = uacpi_namespace_write_lock();
+    if (uacpi_unlikely_error(ret)) {
+        uacpi_recursive_lock_release(&g_opregion_lock);
+        return ret;
+    }
+
+    if (uacpi_unlikely(extract_handlers(device_node) == UACPI_NULL)) {
+        ret = UACPI_STATUS_INVALID_ARGUMENT;
+        goto out;
+    }
+
+    ret = reg_or_unreg_all_opregions(device_node, space, ACPI_REG_CONNECT);
+
+out:
+    uacpi_namespace_write_unlock();
+    uacpi_recursive_lock_release(&g_opregion_lock);
+    return ret;
+}
+
+uacpi_status uacpi_install_address_space_handler_with_flags(
+    uacpi_namespace_node *device_node, enum uacpi_address_space space,
+    uacpi_region_handler handler, uacpi_handle handler_context,
+    uacpi_u16 flags
+)
+{
+    uacpi_status ret;
+    uacpi_address_space_handlers *handlers;
+    uacpi_address_space_handler *this_handler, *new_handler;
+    struct opregion_iter_ctx iter_ctx;
+
+    ret = uacpi_recursive_lock_acquire(&g_opregion_lock);
+    if (uacpi_unlikely_error(ret))
+        return ret;
+
+    ret = uacpi_namespace_write_lock();
+    if (uacpi_unlikely_error(ret)) {
+        uacpi_recursive_lock_release(&g_opregion_lock);
+        return ret;
+    }
+
+    handlers = extract_handlers(device_node);
+    if (uacpi_unlikely(handlers == UACPI_NULL)) {
+        ret = UACPI_STATUS_INVALID_ARGUMENT;
+        goto out;
+    }
+
+    this_handler = find_handler(handlers, space);
+    if (this_handler != UACPI_NULL) {
+        ret = UACPI_STATUS_ALREADY_EXISTS;
+        goto out;
+    }
+
+    new_handler = uacpi_kernel_alloc(sizeof(*new_handler));
+    if (new_handler == UACPI_NULL) {
+        ret = UACPI_STATUS_OUT_OF_MEMORY;
+        goto out;
+    }
+    uacpi_shareable_init(new_handler);
+
+    new_handler->next = handlers->head;
+    new_handler->space = space;
+    new_handler->user_context = handler_context;
+    new_handler->callback = handler;
+    new_handler->regions = UACPI_NULL;
+    new_handler->flags = flags;
+    handlers->head = new_handler;
+
+    iter_ctx.handler = new_handler;
+    iter_ctx.action = OPREGION_ITER_ACTION_INSTALL;
+
+    uacpi_namespace_do_for_each_child(
+        device_node, do_install_or_uninstall_handler, UACPI_NULL,
+        UACPI_OBJECT_ANY_BIT, UACPI_MAX_DEPTH_ANY, UACPI_SHOULD_LOCK_NO,
+        UACPI_PERMANENT_ONLY_YES, &iter_ctx
+    );
+
+    if (!space_needs_reg(space))
+        goto out;
+
+     /*
+      * Installing an early address space handler, obviously not possible to
+      * execute any _REG methods here. Just return and hope that it is either
+      * a global address space handler, or a handler installed by a user who
+      * will run uacpi_reg_all_opregions manually after loading/initializing
+      * the namespace.
+      */
+    if (g_uacpi_rt_ctx.init_level < UACPI_INIT_LEVEL_NAMESPACE_LOADED)
+        goto out;
+
+    // Init level is NAMESPACE_INITIALIZED, so we can safely run _REG now
+    ret = reg_or_unreg_all_opregions(
+        device_node, space, ACPI_REG_CONNECT
+    );
+
+out:
+    uacpi_namespace_write_unlock();
+    uacpi_recursive_lock_release(&g_opregion_lock);
+    return ret;
+}
+
+uacpi_status uacpi_install_address_space_handler(
+    uacpi_namespace_node *device_node, enum uacpi_address_space space,
+    uacpi_region_handler handler, uacpi_handle handler_context
+)
+{
+    return uacpi_install_address_space_handler_with_flags(
+        device_node, space, handler, handler_context, 0
+    );
+}
+
+uacpi_status uacpi_uninstall_address_space_handler(
+    uacpi_namespace_node *device_node,
+    enum uacpi_address_space space
+)
+{
+    uacpi_status ret;
+    uacpi_address_space_handlers *handlers;
+    uacpi_address_space_handler *handler = UACPI_NULL, *prev_handler;
+    struct opregion_iter_ctx iter_ctx;
+
+    ret = uacpi_recursive_lock_acquire(&g_opregion_lock);
+    if (uacpi_unlikely_error(ret))
+        return ret;
+
+    ret = uacpi_namespace_write_lock();
+    if (uacpi_unlikely_error(ret)) {
+        uacpi_recursive_lock_release(&g_opregion_lock);
+        return ret;
+    }
+
+    handlers = extract_handlers(device_node);
+    if (uacpi_unlikely(handlers == UACPI_NULL)) {
+        ret = UACPI_STATUS_INVALID_ARGUMENT;
+        goto out;
+    }
+
+    handler = find_handler(handlers, space);
+    if (uacpi_unlikely(handler == UACPI_NULL)) {
+        ret = UACPI_STATUS_NO_HANDLER;
+        goto out;
+    }
+
+    iter_ctx.handler = handler;
+    iter_ctx.action = OPREGION_ITER_ACTION_UNINSTALL;
+
+    uacpi_namespace_do_for_each_child(
+        device_node, do_install_or_uninstall_handler, UACPI_NULL,
+        UACPI_OBJECT_ANY_BIT, UACPI_MAX_DEPTH_ANY, UACPI_SHOULD_LOCK_NO,
+        UACPI_PERMANENT_ONLY_NO, &iter_ctx
+    );
+
+    prev_handler = handlers->head;
+
+    // Are we the last linked handler?
+    if (prev_handler == handler) {
+        handlers->head = handler->next;
+        goto out_unreg;
+    }
+
+    // Nope, we're somewhere in the middle. Do a search.
+    while (prev_handler) {
+        if (prev_handler->next == handler) {
+            prev_handler->next = handler->next;
+            goto out;
+        }
+
+        prev_handler = prev_handler->next;
+    }
+
+out_unreg:
+    if (space_needs_reg(space))
+        reg_or_unreg_all_opregions(device_node, space, ACPI_REG_DISCONNECT);
+
+out:
+    if (handler != UACPI_NULL)
+        uacpi_address_space_handler_unref(handler);
+
+    uacpi_namespace_write_unlock();
+    uacpi_recursive_lock_release(&g_opregion_lock);
+    return ret;
+}
+
+uacpi_status uacpi_initialize_opregion_node(uacpi_namespace_node *node)
+{
+    uacpi_status ret;
+    uacpi_namespace_node *parent = node->parent;
+    uacpi_operation_region *region;
+    uacpi_address_space_handlers *handlers;
+    uacpi_address_space_handler *handler;
+
+    ret = upgrade_to_opregion_lock();
+    if (uacpi_unlikely_error(ret))
+        return ret;
+
+    region = uacpi_namespace_node_get_object(node)->op_region;
+    ret = UACPI_STATUS_NOT_FOUND;
+
+    while (parent) {
+        handlers = uacpi_node_get_address_space_handlers(parent);
+        if (handlers != UACPI_NULL) {
+            handler = find_handler(handlers, region->space);
+
+            if (handler != UACPI_NULL) {
+                region_install_handler(node, handler);
+                ret = UACPI_STATUS_OK;
+                break;
+            }
+        }
+
+        parent = parent->parent;
+    }
+
+    if (ret != UACPI_STATUS_OK)
+        goto out;
+    if (!space_needs_reg(region->space))
+        goto out;
+    if (uacpi_get_current_init_level() < UACPI_INIT_LEVEL_NAMESPACE_LOADED)
+        goto out;
+
+    if (region_run_reg(node, ACPI_REG_CONNECT) != UACPI_STATUS_NOT_FOUND)
+        region->state_flags |= UACPI_OP_REGION_STATE_REG_EXECUTED;
+
+out:
+    uacpi_recursive_lock_release(&g_opregion_lock);
+    return ret;
+}
+
+uacpi_bool uacpi_is_buffer_access_address_space(uacpi_address_space space)
+{
+    switch (space) {
+    case UACPI_ADDRESS_SPACE_SMBUS:
+    case UACPI_ADDRESS_SPACE_IPMI:
+    case UACPI_ADDRESS_SPACE_GENERIC_SERIAL_BUS:
+    case UACPI_ADDRESS_SPACE_PRM:
+    case UACPI_ADDRESS_SPACE_FFIXEDHW:
+        return UACPI_TRUE;
+    default:
+        return UACPI_FALSE;
+    }
+}
+
+static uacpi_bool space_needs_bounds_checking(uacpi_address_space space)
+{
+    return !uacpi_is_buffer_access_address_space(space) &&
+        space != UACPI_ADDRESS_SPACE_GENERAL_PURPOSE_IO;
+}
+
+uacpi_status uacpi_dispatch_opregion_io(
+    uacpi_field_unit *field, uacpi_u32 offset, uacpi_region_op op,
+    union uacpi_opregion_io_data data
+)
+{
+    uacpi_status ret;
+    uacpi_object *obj;
+    uacpi_operation_region *region;
+    uacpi_address_space_handler *handler;
+    uacpi_address_space space;
+    uacpi_u64 abs_offset, offset_end = offset;
+    uacpi_bool is_oob = UACPI_FALSE;
+    uacpi_region_op orig_op = op;
+
+    union {
+        uacpi_region_rw_data rw;
+        uacpi_region_pcc_send_data pcc;
+        uacpi_region_gpio_rw_data gpio;
+        uacpi_region_ipmi_rw_data ipmi;
+        uacpi_region_ffixedhw_rw_data ffixedhw;
+        uacpi_region_prm_rw_data prm;
+        uacpi_region_serial_rw_data serial;
+    } handler_data;
+
+    ret = upgrade_to_opregion_lock();
+    if (uacpi_unlikely_error(ret))
+        return ret;
+
+    ret = uacpi_opregion_attach(field->region);
+    if (uacpi_unlikely_error(ret)) {
+        uacpi_trace_region_error(
+            field->region, "unable to attach", ret
+        );
+        goto out;
+    }
+
+    obj = uacpi_namespace_node_get_object_typed(
+        field->region, UACPI_OBJECT_OPERATION_REGION_BIT
+    );
+    if (uacpi_unlikely(obj == UACPI_NULL)) {
+        ret = UACPI_STATUS_INVALID_ARGUMENT;
+        goto out;
+    }
+
+    region = obj->op_region;
+    space = region->space;
+    handler = region->handler;
+
+    abs_offset = region->offset + offset;
+    offset_end += field->access_width_bytes;
+
+    if (uacpi_likely(space_needs_bounds_checking(region->space)))
+        is_oob = region->length < offset_end || abs_offset < offset;
+    if (uacpi_unlikely(is_oob)) {
+        const uacpi_char *path;
+
+        path = uacpi_namespace_node_generate_absolute_path(field->region);
+        uacpi_error(
+            "out-of-bounds access to opregion %s[0x%"UACPI_PRIX64"->"
+            "0x%"UACPI_PRIX64"] at 0x%"UACPI_PRIX64" (idx=%u, width=%d)\n",
+            path, UACPI_FMT64(region->offset),
+            UACPI_FMT64(region->offset + region->length),
+            UACPI_FMT64(abs_offset), offset, field->access_width_bytes
+        );
+        uacpi_free_dynamic_string(path);
+        ret = UACPI_STATUS_AML_OUT_OF_BOUNDS_INDEX;
+        goto out;
+    }
+
+    handler_data.rw.region_context = region->user_context;
+    handler_data.rw.handler_context = handler->user_context;
+
+    switch (region->space) {
+    case UACPI_ADDRESS_SPACE_PCC: {
+        uacpi_u8 *cursor;
+
+        cursor = region->internal_buffer + offset;
+
+        /*
+         * Reads from PCC just return the current contents of the internal
+         * buffer.
+         */
+        if (op == UACPI_REGION_OP_READ) {
+            uacpi_memcpy_zerout(
+                data.integer, cursor, sizeof(*data.integer),
+                field->access_width_bytes
+            );
+            goto io_done;
+        }
+
+        uacpi_memcpy(cursor, data.integer, field->access_width_bytes);
+
+        /*
+         * Dispatch a PCC send command if this was a write to the command field
+         *
+         * ACPI 6.5: 14.3. Extended PCC Subspace Shared Memory Region
+         */
+        if (offset >= 12 && offset < 16) {
+            uacpi_memzero(&handler_data.pcc.buffer, sizeof(handler_data.pcc.buffer));
+            handler_data.pcc.buffer.bytes = region->internal_buffer;
+            handler_data.pcc.buffer.length = region->length;
+
+            op = UACPI_REGION_OP_PCC_SEND;
+            break;
+        }
+
+        // No dispatch needed, IO is done
+        goto io_done;
+    }
+    case UACPI_ADDRESS_SPACE_GENERAL_PURPOSE_IO:
+        handler_data.gpio.pin_offset = field->pin_offset;
+        handler_data.gpio.num_pins = field->bit_length;
+        handler_data.gpio.value = *data.integer;
+
+        ret = uacpi_object_get_string_or_buffer(
+            field->connection, &handler_data.gpio.connection
+        );
+        if (uacpi_unlikely_error(ret))
+            goto io_done;
+
+        op = op == UACPI_REGION_OP_READ ?
+            UACPI_REGION_OP_GPIO_READ : UACPI_REGION_OP_GPIO_WRITE;
+        break;
+    case UACPI_ADDRESS_SPACE_IPMI:
+        handler_data.ipmi.in_out_message = data.buffer;
+        handler_data.ipmi.command = abs_offset;
+        op = UACPI_REGION_OP_IPMI_COMMAND;
+        break;
+    case UACPI_ADDRESS_SPACE_FFIXEDHW:
+        handler_data.ffixedhw.in_out_message = data.buffer;
+        handler_data.ffixedhw.command = abs_offset;
+        op = UACPI_REGION_OP_FFIXEDHW_COMMAND;
+        break;
+    case UACPI_ADDRESS_SPACE_PRM:
+        handler_data.prm.in_out_message = data.buffer;
+        op = UACPI_REGION_OP_PRM_COMMAND;
+        break;
+    case UACPI_ADDRESS_SPACE_GENERIC_SERIAL_BUS:
+    case UACPI_ADDRESS_SPACE_SMBUS:
+        ret = uacpi_object_get_string_or_buffer(
+            field->connection, &handler_data.serial.connection
+        );
+        if (uacpi_unlikely_error(ret))
+            goto io_done;
+
+        handler_data.serial.command = abs_offset;
+        handler_data.serial.in_out_buffer = data.buffer;
+        handler_data.serial.access_attribute = field->attributes;
+
+        switch (field->attributes) {
+        case UACPI_ACCESS_ATTRIBUTE_BYTES:
+        case UACPI_ACCESS_ATTRIBUTE_RAW_BYTES:
+        case UACPI_ACCESS_ATTRIBUTE_RAW_PROCESS_BYTES:
+            handler_data.serial.access_length = field->access_length;
+            break;
+        default:
+            handler_data.serial.access_length = 0;
+        }
+
+        op = op == UACPI_REGION_OP_READ ?
+            UACPI_REGION_OP_SERIAL_READ : UACPI_REGION_OP_SERIAL_WRITE;
+        break;
+    default:
+        handler_data.rw.byte_width = field->access_width_bytes;
+        handler_data.rw.offset = abs_offset;
+        handler_data.rw.value = *data.integer;
+        break;
+    }
+
+    uacpi_object_ref(obj);
+    uacpi_namespace_write_unlock();
+
+    ret = handler->callback(op, &handler_data);
+
+    uacpi_namespace_write_lock();
+    uacpi_object_unref(obj);
+
+io_done:
+    if (uacpi_unlikely_error(ret)) {
+        uacpi_trace_region_error(field->region, "unable to perform IO", ret);
+        goto out;
+    }
+
+    if (orig_op == UACPI_REGION_OP_READ) {
+        switch (region->space) {
+        case UACPI_ADDRESS_SPACE_PCC:
+        case UACPI_ADDRESS_SPACE_IPMI:
+        case UACPI_ADDRESS_SPACE_FFIXEDHW:
+        case UACPI_ADDRESS_SPACE_PRM:
+        case UACPI_ADDRESS_SPACE_GENERIC_SERIAL_BUS:
+        case UACPI_ADDRESS_SPACE_SMBUS:
+            break;
+        case UACPI_ADDRESS_SPACE_GENERAL_PURPOSE_IO:
+            *data.integer = handler_data.gpio.value;
+            break;
+        default:
+            *data.integer = handler_data.rw.value;
+            break;
+        }
+    }
+
+    trace_region_io(field, space, abs_offset, orig_op, data);
+
+out:
+    uacpi_recursive_lock_release(&g_opregion_lock);
+    return ret;
+}
+
+#endif // !UACPI_BAREBONES_MODE