On 5/22/2015 6:05 PM, Rafael J. Wysocki wrote:
On Friday, May 22, 2015 05:24:15 PM Suravee Suthikulanit wrote:
Not sure if this went out earlier. So I am resending.
On 5/22/15 16:56, Rafael J. Wysocki wrote:
diff --git a/drivers/acpi/glue.c b/drivers/acpi/glue.c
index 39c485b..b9657af 100644 --- a/drivers/acpi/glue.c +++ b/drivers/acpi/glue.c @@ -13,6 +13,7 @@ #include <linux/slab.h> #include <linux/rwsem.h> #include <linux/acpi.h> +#include <linux/dma-mapping.h>
#include "internal.h"
@@ -167,6 +168,7 @@ int acpi_bind_one(struct device *dev, struct acpi_device *acpi_dev) struct list_head *physnode_list; unsigned int node_id; int retval = -EINVAL;
bool coherent;
if (has_acpi_companion(dev)) { if (acpi_dev) {
@@ -223,6 +225,9 @@ int acpi_bind_one(struct device *dev, struct acpi_device *acpi_dev) if (!has_acpi_companion(dev)) ACPI_COMPANION_SET(dev, acpi_dev);
- if (acpi_check_dma(acpi_dev, &coherent))
arch_setup_dma_ops(dev, 0, 0, NULL, coherent);Well, so is this going to work for PCI too after all?
No, as Bjorn suggested, PCI changes for setting DMA coherent from _CCA (patch 3/6 in V4) will be submitted separately. We are working on cleaning up and up-streaming the PCI ACPI support for ARM64.
OK, but acpi_bind_one() is called for PCI devices too. Won't that be a problem?
In this case, we would be going through the following call path:
--> pci_device_add() |--> pci_dma_configure() ** 1 ** |--> device_add() |--> platform_notify() |--> acpi_platform_notify() |--> acpi_bind_one() ** 2 **
At (1), we would be calling arch_setup_dma_ops() with the PCI host bridge _CCA information. So, it should have already taken care of setting up device coherency here.
At (2), if there is no acpi_dev for endpoint devices (which I believe this is normally the case), it would return early and skip arch_setup_dma_ops().
At (2), if there is an acpi_dev, the coherent_dma flag should have already been setup by the acpi_init_device_object during ACPI scan. However, I am not certain about this case since I don't have the DSDT containing PCI endpoint devices to test with.
Thanks,
Suravee