On 5/22/2015 8:25 PM, Rafael J. Wysocki wrote:
On Friday, May 22, 2015 07:15:17 PM Suravee Suthikulanit wrote:
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().
That's not correct. There may be ACPI companions for endpoint devices too.
Ok. Duly noted :)
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.
That one sets the flag for the *ACPI* *companion* of the device, which
I'm still thinking is pointless, isn't it?
When you say pointless, are you referring to the part where we are end
up calling arch_setup_dma_coherent() twice in this case? I am not quite
following your point.
However, I am not certain about this case since I don't have the DSDT
containing PCI endpoint devices to test with.
Every x86 PC has them (as far as I can say), but in that case there's no
_CCA and they are all coherent.
Ok.
Thanks,
Suravee
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