memory: Provide memory_region_init_rom()

Provide a new helper function memory_region_init_rom() for memory
regions which are read-only (and unlike those created by
memory_region_init_rom_device() don't have special behaviour
for writes). This has the same behaviour as calling
memory_region_init_ram() and then memory_region_set_readonly()
(which is what we do today in boards with pure ROMs) but is a
more easily discoverable API for the purpose.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Message-id: 1467122287-24974-2-git-send-email-peter.maydell@linaro.org
This commit is contained in:
Peter Maydell 2016-07-04 13:06:35 +01:00
parent f5666418c4
commit a1777f7f64
3 changed files with 41 additions and 2 deletions

View file

@ -41,8 +41,13 @@ MemoryRegion):
MemoryRegionOps structure describing the callbacks.
- ROM: a ROM memory region works like RAM for reads (directly accessing
a region of host memory), but like MMIO for writes (invoking a callback).
You initialize these with memory_region_init_rom_device().
a region of host memory), and forbids writes. You initialize these with
memory_region_init_rom().
- ROM device: a ROM device memory region works like RAM for reads
(directly accessing a region of host memory), but like MMIO for
writes (invoking a callback). You initialize these with
memory_region_init_rom_device().
- IOMMU region: an IOMMU region translates addresses of accesses made to it
and forwards them to some other target memory region. As the name suggests,

View file

@ -444,6 +444,25 @@ void memory_region_init_alias(MemoryRegion *mr,
hwaddr offset,
uint64_t size);
/**
* memory_region_init_rom: Initialize a ROM memory region.
*
* This has the same effect as calling memory_region_init_ram()
* and then marking the resulting region read-only with
* memory_region_set_readonly().
*
* @mr: the #MemoryRegion to be initialized.
* @owner: the object that tracks the region's reference count
* @name: the name of the region.
* @size: size of the region.
* @errp: pointer to Error*, to store an error if it happens.
*/
void memory_region_init_rom(MemoryRegion *mr,
struct Object *owner,
const char *name,
uint64_t size,
Error **errp);
/**
* memory_region_init_rom_device: Initialize a ROM memory region. Writes are
* handled via callbacks.

View file

@ -1376,6 +1376,21 @@ void memory_region_init_alias(MemoryRegion *mr,
mr->alias_offset = offset;
}
void memory_region_init_rom(MemoryRegion *mr,
struct Object *owner,
const char *name,
uint64_t size,
Error **errp)
{
memory_region_init(mr, owner, name, size);
mr->ram = true;
mr->readonly = true;
mr->terminates = true;
mr->destructor = memory_region_destructor_ram;
mr->ram_block = qemu_ram_alloc(size, mr, errp);
mr->dirty_log_mask = tcg_enabled() ? (1 << DIRTY_MEMORY_CODE) : 0;
}
void memory_region_init_rom_device(MemoryRegion *mr,
Object *owner,
const MemoryRegionOps *ops,