On 21/1/22 8:18 am, Alex White wrote:
> On Thu, Jan 20, 2022 at 12:30 AM Chris Johns <chr...@rtems.org> wrote:
>>
>> On 20/1/22 2:54 pm, Alex White wrote:
>>> From: Jennifer Averett <jennifer.aver...@oarcorp.com>
>>> rtemsbsd/rtems/rtems-kernel-vmem.c | 17 +
>>> diff --git a/rtemsbsd/rtems/rtems-kernel-vmem.c
>>> b/rtemsbsd/rtems/rtems-kernel-vmem.c
>>> index f64fbd17..70708902 100644
>>> --- a/rtemsbsd/rtems/rtems-kernel-vmem.c
>>> +++ b/rtemsbsd/rtems/rtems-kernel-vmem.c
>>> @@ -41,6 +41,11 @@
>>>
>>> static MALLOC_DEFINE(M_VMEM, "vmem", "VMEM buffers");
>>>
>>> +int vmem_add(vmem_t *vm, vmem_addr_t addr, vmem_size_t size, int flags)
>>> +{
>>> + return 0;
>>> +}
>>> +
>>> int
>>> vmem_alloc(vmem_t *vm, vmem_size_t size, int flags, vmem_addr_t *addrp)
>>> {
>>> @@ -48,6 +53,18 @@ vmem_alloc(vmem_t *vm, vmem_size_t size, int flags,
>>> vmem_addr_t *addrp)
>>> return 0;
>>> }
>>>
>>> +static int dummy_vmem;
>>> +
>>> +vmem_t *vmem_create(const char *name, vmem_addr_t base,
>>> + vmem_size_t size, vmem_size_t quantum, vmem_size_t qcache_max, int
>>> flags)
>>> +{
>>> + return &dummy_vmem;
>>> +}
>>> +
>>> +void vmem_destroy(vmem_t *vm)
>>> +{
>>> +}
>>> +
>>> void
>>> vmem_free(vmem_t *vm, vmem_addr_t addr, vmem_size_t size)
>>> {
>>
>> What is pulling this interface in?
>
> The added vmem functions are pulled in by freebsd/sys/dev/xdma/xdma.c
So how can it be an empty stub and the XDMA driver operate? Is the allocator
being called?
>>
>> Why have they been stubbed out?
>
> They were stubbed out to provide the minimal implementation needed to get
> xdma working, and xdma is ultimately used by the AXI Ethernet subsystem.
>
> The alternatives we saw were to pull in the full FreeBSD vmem implementation
> (overkill) or modify
> freebsd/sys/dev/xdma/xdma.c to not use vmem functions.
What sort of memory does this allocator allocate? Can some heap memory be used?
Chris
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