From: Tomasz Nowicki <tn@semihalf.com>
To: Robin Murphy <robin.murphy@arm.com>,
Timur Tabi <timur@codeaurora.org>,
Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Cc: "linux-arm-kernel@lists.infradead.org"
<linux-arm-kernel@lists.infradead.org>,
vikrams@codeaurora.org, Marc Zyngier <marc.zyngier@arm.com>,
"Rafael J. Wysocki" <rjw@rjwysocki.net>,
lkml <linux-kernel@vger.kernel.org>,
Will Deacon <will.deacon@arm.com>,
Sinan Kaya <okaya@codeaurora.org>,
linux-acpi@vger.kernel.org, iommu@lists.linux-foundation.org,
Hanjun Guo <hanjun.guo@linaro.org>,
linux-pci@vger.kernel.org, Bjorn Helgaas <bhelgaas@google.com>,
Jon Masters <jcm@redhat.com>
Subject: Re: [RFC PATCH 09/11] drivers: acpi: implement acpi_dma_configure
Date: Mon, 16 May 2016 17:15:34 +0200 [thread overview]
Message-ID: <5739E416.6000501@semihalf.com> (raw)
In-Reply-To: <5714BA5A.2040008@arm.com>
On 18.04.2016 12:43, Robin Murphy wrote:
> On 15/04/16 19:29, Timur Tabi wrote:
>> On Thu, Apr 14, 2016 at 12:25 PM, Lorenzo Pieralisi
>> <lorenzo.pieralisi@arm.com> wrote:
>>> +void acpi_dma_configure(struct device *dev, enum dev_dma_attr attr)
>>> +{
>>> + struct iommu_ops *iommu;
>>> +
>>> + iommu = iort_iommu_configure(dev);
>>> +
>>> + /*
>>> + * Assume dma valid range starts at 0 and covers the whole
>>> + * coherent_dma_mask.
>>> + */
>>> + arch_setup_dma_ops(dev, 0, dev->coherent_dma_mask + 1, iommu,
>>> + attr == DEV_DMA_COHERENT);
>>> +}
>>
>> I have a network driver that is impacted by this code, so thank you
>> for posting this. (See
>> https://www.mail-archive.com/netdev@vger.kernel.org/msg106249.html).
>>
>> One one SOC, the driver needs to set the mask to 32 bits. On another
>> SOC, it needs to set it to 64 bits. On device tree, the driver will
>> use dma-ranges.
>
> That's the wrong way to look at it - the driver isn't _using_
> dma-ranges, you're merely relying on the OF code setting the _default_
> DMA mask differently based on the property. If your driver is in the
> minority of those which actually care about DMA masks, then it should be
> calling dma_set_mask_and_coherent() appropriately and not relying on the
> default.
I don't see the clear strategy for setting DMA mask as well.
Lets consider DT boot method example:
1. SMMUv2 supports 48bit translation and 1:1 address map
dma-ranges = <0x0 0x0 0x0 0x0 0x00010000 0x0>;
and we are adding PCI device:
pci_device_add -> DMA_BIT_MASK(32) by default
pci_dma_configure
of_dma_configure -> reads dma-ranges and calculates 48bit DMA mask,
but it picks minimum, we stay with DMA_BIT_MASK(32)
now PCI dev turns out to be e1000e NIC:
e1000_probe
dma_set_mask_and_coherent -> tries to set DMA_BIT_MASK(64)
dma_set_mask -> there is no set_dma_mask ops for SMMUv2 so we let
it be DMA_BIT_MASK(64). From that point on, we let to use memory which
SMMUv2 cannot work with.
Does lack of set_dma_mask is the only missing thing here?
Thanks,
Tomasz
next prev parent reply other threads:[~2016-05-16 15:15 UTC|newest]
Thread overview: 26+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-04-14 17:25 [RFC PATCH 00/11] ACPI IORT ARM SMMU support Lorenzo Pieralisi
2016-04-14 17:25 ` [RFC PATCH 01/11] drivers: acpi: iort: fix struct pci_dev compiler warnings Lorenzo Pieralisi
2016-04-14 17:25 ` [RFC PATCH 02/11] drivers: acpi: iort: add support for IOMMU registration Lorenzo Pieralisi
2016-04-14 17:25 ` [RFC PATCH 03/11] drivers: iommu: add FWNODE_IOMMU fwnode type Lorenzo Pieralisi
2016-04-14 17:25 ` [RFC PATCH 04/11] drivers: acpi: iort: introduce linker section for IORT entries probing Lorenzo Pieralisi
2016-04-14 17:25 ` [RFC PATCH 05/11] drivers: iommu: arm-smmu: split probe functions into DT/generic portions Lorenzo Pieralisi
2016-04-14 17:25 ` [RFC PATCH 06/11] drivers: iommu: make of_xlate() interface DT agnostic Lorenzo Pieralisi
2016-04-19 8:28 ` Marek Szyprowski
2016-04-19 11:30 ` Lorenzo Pieralisi
2016-04-20 7:14 ` Marek Szyprowski
2016-04-14 17:25 ` [RFC PATCH 07/11] drivers: iommu: arm-smmu: allow ACPI based streamid translation Lorenzo Pieralisi
2016-04-14 17:25 ` [RFC PATCH 08/11] drivers: acpi: iort: enhance mapping API Lorenzo Pieralisi
2016-04-14 17:25 ` [RFC PATCH 09/11] drivers: acpi: implement acpi_dma_configure Lorenzo Pieralisi
2016-04-15 16:14 ` Bjorn Helgaas
2016-04-15 16:31 ` Robin Murphy
2016-04-15 18:29 ` Timur Tabi
2016-04-18 10:30 ` Lorenzo Pieralisi
2016-04-18 10:43 ` Robin Murphy
2016-05-16 15:15 ` Tomasz Nowicki [this message]
2016-05-16 15:26 ` Tomasz Nowicki
2016-04-21 22:45 ` Andy Shevchenko
2016-04-22 10:57 ` Lorenzo Pieralisi
2016-05-17 8:07 ` Tomasz Nowicki
2016-05-17 12:32 ` Tomasz Nowicki
2016-04-14 17:25 ` [RFC PATCH 10/11] drivers: iommu: arm-smmu: implement ACPI probing Lorenzo Pieralisi
2016-04-14 17:25 ` [RFC PATCH 11/11] drivers: irqchip: make struct irq_fwspec generic Lorenzo Pieralisi
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