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