Re: [PATCH V2 4/4] PCI: ACPI: Add support for PCI device DMA coherency

From: Suravee Suthikulpanit
Date: Tue Aug 25 2015 - 22:02:16 EST

Hi Rafael,

On 8/26/15 06:48, Rafael J. Wysocki wrote:
On Wednesday, August 26, 2015 12:33:29 AM Suravee Suthikulpanit wrote:
This patch adds support for setting up PCI device DMA coherency from
ACPI _CCA object that should normally be specified in the DSDT node
of its PCI host bridge.

Signed-off-by: Suravee Suthikulpanit <Suravee.Suthikulpanit@xxxxxxx>
CC: Bjorn Helgaas <bhelgaas@xxxxxxxxxx>
CC: Catalin Marinas <catalin.marinas@xxxxxxx>
CC: Rob Herring <robh+dt@xxxxxxxxxx>
CC: Will Deacon <will.deacon@xxxxxxx>
CC: Rafael J. Wysocki <rjw@xxxxxxxxxxxxx>
CC: Murali Karicheri <m-karicheri2@xxxxxx>
drivers/pci/probe.c | 15 ++++++++++-----
1 file changed, 10 insertions(+), 5 deletions(-)

diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c
index 4de6594..2fd2a60 100644
--- a/drivers/pci/probe.c
+++ b/drivers/pci/probe.c
@@ -1551,17 +1551,22 @@ static void pci_init_capabilities(struct pci_dev *dev)
* @dev: ptr to pci_dev struct of the PCI device
* Function to update PCI devices's DMA configuration using the same
- * info from the OF node of host bridge's parent (if any).
+ * info from the OF node or ACPI node of host bridge's parent (if any).
static void pci_dma_configure(struct pci_dev *dev)
struct device *bridge = pci_get_host_bridge_device(dev);

if (IS_ENABLED(CONFIG_OF) && dev->dev.of_node) {
- if (!bridge->parent)
- return;
- of_dma_configure(&dev->dev, bridge->parent->of_node);
+ if (bridge->parent)
+ of_dma_configure(&dev->dev,
+ bridge->parent->of_node);
+ } else if (has_acpi_companion(bridge)) {
+ struct acpi_device *adev = to_acpi_node(bridge->fwnode);
+ int coherent = acpi_check_dma_coherency(adev);
+ if (-1 != coherent)

The ordering of this check is somewhat unusual.

I'll fix this.

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