[PATCH v2 01/15] xen: Clean up asm-generic/device.h

[Alejandro Vallejo <agarciav@xxxxxxx>]

There's some pretense this header may be used without
CONFIG_HAS_DEVICE_TREE, but that's just wishful thinking. Only x86 lacks
that option, and it fully overrides this header, typedeffing struct
pci_dev to be device_t.

Furthermore there's an include for xen/device_tree.h halfway through the
header, but that header already includes asm/device.h, creating a cycle.

Clean up the header removing ifdef guards, merging the typedef onto the
struct definition for device_t and removing the spurious include.

The only affected file is aplic.c, in riscv, which is forced now to
include device_tree.h directly.

Not a functional change.

Signed-off-by: Alejandro Vallejo <agarciav@xxxxxxx>
Reviewed-by: Stefano Stabellini <sstabellini@xxxxxxxxxx>
---
v2:
  * Add new comment and ifdef guard with #error
---
 xen/arch/riscv/aplic.c           |  3 ++-
 xen/include/asm-generic/device.h | 26 ++++++++++----------------
 2 files changed, 12 insertions(+), 17 deletions(-)

diff --git a/xen/arch/riscv/aplic.c b/xen/arch/riscv/aplic.c
index 10ae81f7ac..dd7a274c52 100644
--- a/xen/arch/riscv/aplic.c
+++ b/xen/arch/riscv/aplic.c
@@ -9,13 +9,14 @@
  * Copyright (c) 2024-2025 Vates
  */
 
+#include <xen/device_tree.h>
 #include <xen/errno.h>
 #include <xen/init.h>
+#include <xen/lib.h>
 #include <xen/irq.h>
 #include <xen/sections.h>
 #include <xen/types.h>
 
-#include <asm/device.h>
 #include <asm/intc.h>
 
 static struct intc_info __ro_after_init aplic_info = {
diff --git a/xen/include/asm-generic/device.h b/xen/include/asm-generic/device.h
index 1acd1ba1d8..631dab046a 100644
--- a/xen/include/asm-generic/device.h
+++ b/xen/include/asm-generic/device.h
@@ -1,14 +1,20 @@
 /* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * This header helps DTB-based architectures abstract away where a particular
+ * device came from, be it the DTB itself or enumerated on a PCI bus.
+ */
 #ifndef __ASM_GENERIC_DEVICE_H__
 #define __ASM_GENERIC_DEVICE_H__
 
+#ifndef CONFIG_HAS_DEVICE_TREE
+#error "Header for exclusive use of DTB-based architectures"
+#endif
+
 #include <xen/stdbool.h>
 
 enum device_type
 {
-#ifdef CONFIG_HAS_DEVICE_TREE
     DEV_DT,
-#endif
     DEV_PCI
 };
 
@@ -23,23 +29,15 @@ enum device_class
 };
 
 /* struct device - The basic device structure */
-struct device
+typedef struct device
 {
     enum device_type type;
-#ifdef CONFIG_HAS_DEVICE_TREE
     struct dt_device_node *of_node; /* Used by drivers imported from Linux */
-#endif
 #ifdef CONFIG_HAS_PASSTHROUGH
     void *iommu; /* IOMMU private data */;
     struct iommu_fwspec *iommu_fwspec; /* per-device IOMMU instance data */
 #endif
-};
-
-typedef struct device device_t;
-
-#ifdef CONFIG_HAS_DEVICE_TREE
-
-#include <xen/device_tree.h>
+} device_t;
 
 #define dev_is_dt(dev)  ((dev)->type == DEV_DT)
 
@@ -87,10 +85,6 @@ struct device_desc {
     int (*init)(struct dt_device_node *dev, const void *data);
 };
 
-#else /* !CONFIG_HAS_DEVICE_TREE */
-#define dev_is_dt(dev) ((void)(dev), false)
-#endif /* CONFIG_HAS_DEVICE_TREE */
-
 #define dev_is_pci(dev) ((dev)->type == DEV_PCI)
 
 #ifdef CONFIG_ACPI
-- 
2.43.0