Hi Dennis,
On 11/02/2015 12:02 PM, Dennis Chen wrote:
On Thu, Oct 29, 2015 at 6:50 AM, Suravee Suthikulpanit
<suravee.suthikulpa...@amd.com> wrote:
From: Jeremy Linton <jeremy.lin...@arm.com>
ACPI configurations can now mark devices as noncoherent,
support that choice.
NOTE: This is required to support USB on ARM Juno Development Board.
Signed-off-by: Jeremy Linton <jeremy.lin...@arm.com>
Signed-off-by: Suravee Suthikulpanit <suravee.suthikulpa...@amd.com>
CC: Bjorn Helgaas <bhelg...@google.com>
CC: Catalin Marinas <catalin.mari...@arm.com>
CC: Rob Herring <robh...@kernel.org>
CC: Will Deacon <will.dea...@arm.com>
CC: Rafael J. Wysocki <r...@rjwysocki.net>
---
include/acpi/acpi_bus.h | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)
diff --git a/include/acpi/acpi_bus.h b/include/acpi/acpi_bus.h
index d11eff8..0f131d2 100644
--- a/include/acpi/acpi_bus.h
+++ b/include/acpi/acpi_bus.h
@@ -407,7 +407,7 @@ static inline bool acpi_check_dma(struct acpi_device *adev,
bool *coherent)
* case 1. Do not support and disable DMA.
* case 2. Support but rely on arch-specific cache maintenance for
* non-coherence DMA operations.
- * Currently, we implement case 1 above.
+ * Currently, we implement case 2 above.
*
* For the case when _CCA is missing (i.e. cca_seen=0) and
* platform specifies ACPI_CCA_REQUIRED, we do not support DMA,
@@ -415,7 +415,8 @@ static inline bool acpi_check_dma(struct acpi_device *adev,
bool *coherent)
*
* See acpi_init_coherency() for more info.
*/
- if (adev->flags.coherent_dma) {
+ if (adev->flags.coherent_dma ||
+ (adev->flags.cca_seen && IS_ENABLED(CONFIG_ARM64))) {
ret = true;
if (coherent)
*coherent = adev->flags.coherent_dma;
Hi Suravee,
The acpi_check_dma function has been removed in patch 6 of this patch set, why
it is still be used
here, am I missing something? If the acpi_check_dma will be used in the future,
personally I'd like
I think this patch just to let people know that there is
case that arch-specific cache maintenance is still needed
for ACPI (such as Juno board), and in the later patches will
cover this case.
acpi_check_dma() will be replaced by acpi_get_dma_attr(),
and in acpi_get_dma_attr() will cover that case and will
be easily understood. (Suravee, correct me if I'm wrong :) )
to use IS_ENABLED(CONFIG_ACPI_CCA_REQUIRED) while not CONFIG_ARM64 macro here,
or since _CCA attribute
is arch-specific, it's reasonable to leave the _CCA handling policy to the
arch-specific code. For example,
with a link weak function like acpi_arch_check_dma() as a default handling if
no arch-specific code
provided, the actual _CCA handling will be implemented in the ARM, Intel or
other Arch if required.
Actually Intel platform don't need _CCA and it's coherent
in default, since _CCA is in ACPI spec, I would like it's
handled in ACPI core.
Thanks
Hanjun
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