Messages in this thread | | | Date | Fri, 22 May 2015 20:38:28 -0500 | From | Suravee Suthikulanit <> | Subject | Re: [V5 PATCH 1/5] ACPI / scan: Parse _CCA and setup device coherency |
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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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