On Tue, Nov 26, 2019 at 13:11:34 +0100, Ard Biesheuvel wrote:
> On Tue, 26 Nov 2019 at 13:04, Leif Lindholm <[email protected]> wrote:
> >
> > On Tue, Nov 26, 2019 at 00:12:41 +0100, Ard Biesheuvel wrote:
> > > Implement support for driving peripherals with limited DMA ranges to
> > > NonCoherentDmaLib, by adding a device address limit, and taking it,
> > > along with the device offset, into account when allocating or mapping
> > > DMA buffers.
> > >
> > > Signed-off-by: Ard Biesheuvel <[email protected]>
> > > ---
> > > EmbeddedPkg/EmbeddedPkg.dec | 6 +
> > > EmbeddedPkg/Library/NonCoherentDmaLib/NonCoherentDmaLib.c | 165
> > > ++++++++++++++++++--
> > > EmbeddedPkg/Library/NonCoherentDmaLib/NonCoherentDmaLib.inf | 1 +
> > > 3 files changed, 160 insertions(+), 12 deletions(-)
> > >
> > > diff --git a/EmbeddedPkg/EmbeddedPkg.dec b/EmbeddedPkg/EmbeddedPkg.dec
> > > index 8812a6db7c30..69922802f473 100644
> > > --- a/EmbeddedPkg/EmbeddedPkg.dec
> > > +++ b/EmbeddedPkg/EmbeddedPkg.dec
> > > @@ -186,6 +186,12 @@ [PcdsFixedAtBuild.common, PcdsDynamic.common]
> > > #
> > > gEmbeddedTokenSpaceGuid.PcdDmaDeviceOffset|0x0|UINT64|0x0000058
> > >
> > > + #
> > > + # Highest address value supported by the device for DMA addressing.
> > > Note
> > > + # that this value should be strictly greater than PcdDmaDeviceOffset.
> > > + #
> > > +
> > > gEmbeddedTokenSpaceGuid.PcdDmaDeviceLimit|0xFFFFFFFFFFFFFFFF|UINT64|0x000005A
> > > +
> > > #
> > > # Selection between DT and ACPI as a default
> > > #
> > > diff --git a/EmbeddedPkg/Library/NonCoherentDmaLib/NonCoherentDmaLib.c
> > > b/EmbeddedPkg/Library/NonCoherentDmaLib/NonCoherentDmaLib.c
> > > index 78220f6358aa..115345765435 100644
> > > --- a/EmbeddedPkg/Library/NonCoherentDmaLib/NonCoherentDmaLib.c
> > > +++ b/EmbeddedPkg/Library/NonCoherentDmaLib/NonCoherentDmaLib.c
> > > @@ -40,6 +40,8 @@ typedef struct {
> > > STATIC EFI_CPU_ARCH_PROTOCOL *mCpu;
> > > STATIC LIST_ENTRY UncachedAllocationList;
> > >
> > > +STATIC PHYSICAL_ADDRESS mDmaHostAddressLimit;
> > > +
> > > STATIC
> > > PHYSICAL_ADDRESS
> > > HostToDeviceAddress (
> > > @@ -49,6 +51,102 @@ HostToDeviceAddress (
> > > return (PHYSICAL_ADDRESS)(UINTN)Address + PcdGet64
> > > (PcdDmaDeviceOffset);
> > > }
> > >
> > > +/**
> > > + Allocates one or more 4KB pages of a certain memory type at a specified
> > > + alignment.
> > > +
> > > + Allocates the number of 4KB pages specified by Pages of a certain
> > > memory type
> > > + with an alignment specified by Alignment. The allocated buffer is
> > > returned.
> > > + If Pages is 0, then NULL is returned. If there is not enough memory at
> > > the
> > > + specified alignment remaining to satisfy the request, then NULL is
> > > returned.
> > > + If Alignment is not a power of two and Alignment is not zero, then
> > > ASSERT().
> > > + If Pages plus EFI_SIZE_TO_PAGES (Alignment) overflows, then ASSERT().
> > > +
> > > + @param MemoryType The type of memory to allocate.
> > > + @param Pages The number of 4 KB pages to allocate.
> > > + @param Alignment The requested alignment of the
> > > allocation.
> > > + Must be a power of two.
> > > + If Alignment is zero, then byte
> > > alignment is
> > > + used.
> > > +
> > > + @return A pointer to the allocated buffer or NULL if allocation fails.
> > > +
> > > +**/
> > > +STATIC
> > > +VOID *
> > > +InternalAllocateAlignedPages (
> > > + IN EFI_MEMORY_TYPE MemoryType,
> > > + IN UINTN Pages,
> > > + IN UINTN Alignment
> > > + )
> > > +{
> > > + EFI_STATUS Status;
> > > + EFI_PHYSICAL_ADDRESS Memory;
> > > + UINTN AlignedMemory;
> > > + UINTN AlignmentMask;
> > > + UINTN UnalignedPages;
> > > + UINTN RealPages;
> > > +
> > > + //
> > > + // Alignment must be a power of two or zero.
> > > + //
> > > + ASSERT ((Alignment & (Alignment - 1)) == 0);
> >
> > Sorry, slight mental glitch (and I realise this is in copied code) -
> > the above also matches for an Alignment of 1, which contradicts the
> > comment. Clearly requesting allocation explicitly aligned to 1 is a)
> > silly, b) the same as what happens for any value <= EFI_PAGE_SIZE
> > in the below code, and c) harmless, but could you update the comment?
> >
> > If so:
> > Acked-by: Leif Lindholm <[email protected]>
>
> Given that 1 == 2^0, it is also a power of 2, and so the comment is
> accurate imho
I ... guess that's true.
Sure.
/
Leif
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