From: robin.murphy@arm•com (Robin Murphy)
To: linux-arm-kernel@lists•infradead.org
Subject: [PATCH v6 2/3] arm64: Add IOMMU dma_ops
Date: Wed, 7 Oct 2015 17:36:24 +0100 [thread overview]
Message-ID: <56154A08.6060207@arm.com> (raw)
In-Reply-To: <CAAhSdy2tpAfH+i=1axDkmRqZixsbVhd-_9VGvpyQ=5e06v=Kpg@mail.gmail.com>
On 07/10/15 10:03, Anup Patel wrote:
[...]
>> +static bool do_iommu_attach(struct device *dev, const struct iommu_ops *ops,
>> + u64 dma_base, u64 size)
>> +{
>> + struct iommu_domain *domain = iommu_get_domain_for_dev(dev);
>> +
>> + /*
>> + * Best case: The device is either part of a group which was
>> + * already attached to a domain in a previous call, or it's
>> + * been put in a default DMA domain by the IOMMU core.
>> + */
>> + if (!domain) {
>> + /*
>> + * Urgh. The IOMMU core isn't going to do default domains
>> + * for non-PCI devices anyway, until it has some means of
>> + * abstracting the entirely implementation-specific
>> + * sideband data/SoC topology/unicorn dust that may or
>> + * may not differentiate upstream masters.
>> + * So until then, HORRIBLE HACKS!
>> + */
>> + domain = ops->domain_alloc(IOMMU_DOMAIN_DMA);
>> + if (!domain)
>> + goto out_no_domain;
>> +
>> + domain->ops = ops;
>> + domain->type = IOMMU_DOMAIN_DMA | __IOMMU_DOMAIN_FAKE_DEFAULT;
>
> We require iommu_get_dma_cookie(domain) here. If we dont
> allocate iommu cookie then iommu_dma_init_domain() will fail.
The iova cookie is tightly coupled with the domain, so it really only
makes sense for the IOMMU driver to deal with it as part of its
domain_alloc/domain_free callbacks.
Doing that here was one of the nastier 'compatibility' hacks which I've
now taken out; trying to make things work without modifying existing
IOMMU drivers was just too impractical. Drivers which want to play are
now required to support the IOMMU_DOMAIN_DMA type appropriately, but
it's still only a minimal change, as per the example diff for the ARM
SMMU driver below (big pile of further patches necessary to make said
driver compatible in other respects notwithstanding).
Robin.
--->8---
@@ -29,6 +29,7 @@
#define pr_fmt(fmt) "arm-smmu: " fmt
#include <linux/delay.h>
+#include <linux/dma-iommu.h>
#include <linux/dma-mapping.h>
#include <linux/err.h>
#include <linux/interrupt.h>
@@ -973,7 +974,7 @@ static struct iommu_domain
*arm_smmu_domain_alloc(unsigned type)
{
struct arm_smmu_domain *smmu_domain;
- if (type != IOMMU_DOMAIN_UNMANAGED)
+ if (type != IOMMU_DOMAIN_UNMANAGED && type != IOMMU_DOMAIN_DMA)
return NULL;
/*
* Allocate the domain and initialise some of its data structures.
@@ -984,6 +985,12 @@ static struct iommu_domain
*arm_smmu_domain_alloc(unsigned type)
if (!smmu_domain)
return NULL;
+ if (type == IOMMU_DOMAIN_DMA &&
+ iommu_get_dma_cookie(&smmu_domain->domain)) {
+ kfree(smmu_domain);
+ return NULL;
+ }
+
mutex_init(&smmu_domain->init_mutex);
spin_lock_init(&smmu_domain->pgtbl_lock);
@@ -998,6 +1005,7 @@ static void arm_smmu_domain_free(struct
iommu_domain *domain)
* Free the domain resources. We assume that all devices have
* already been detached.
*/
+ iommu_put_dma_cookie(domain);
arm_smmu_destroy_domain_context(domain);
kfree(smmu_domain);
}
next prev parent reply other threads:[~2015-10-07 16:36 UTC|newest]
Thread overview: 37+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-10-01 19:13 [PATCH v6 0/3] arm64: IOMMU-backed DMA mapping Robin Murphy
2015-10-01 19:13 ` [PATCH v6 1/3] iommu: Implement common IOMMU ops for " Robin Murphy
2015-10-26 13:44 ` Yong Wu
2015-10-26 16:55 ` Robin Murphy
2015-10-30 1:17 ` Daniel Kurtz
2015-10-30 14:09 ` Joerg Roedel
2015-10-30 14:27 ` Robin Murphy
2015-11-02 13:11 ` Daniel Kurtz
2015-11-02 13:43 ` Tomasz Figa
2015-11-03 17:41 ` Robin Murphy
2015-11-03 18:40 ` Russell King - ARM Linux
2015-11-04 5:15 ` Tomasz Figa
2015-11-04 9:10 ` Russell King - ARM Linux
2015-11-04 5:12 ` Tomasz Figa
2015-11-04 9:27 ` Russell King - ARM Linux
2015-11-04 9:48 ` Tomasz Figa
2015-11-04 10:50 ` Russell King - ARM Linux
2015-11-09 13:11 ` Robin Murphy
2015-11-17 12:02 ` Marek Szyprowski
2015-10-01 19:13 ` [PATCH v6 2/3] arm64: Add IOMMU dma_ops Robin Murphy
2015-10-06 11:00 ` Yong Wu
2015-10-07 16:07 ` Robin Murphy
2015-10-09 5:44 ` Yong Wu
2015-10-07 9:03 ` Anup Patel
2015-10-07 16:36 ` Robin Murphy [this message]
2015-10-07 17:40 ` Anup Patel
2015-10-14 11:47 ` Joerg Roedel
2015-10-14 13:35 ` Catalin Marinas
2015-10-14 16:34 ` Robin Murphy
2015-11-04 8:39 ` Yong Wu
2015-11-04 13:11 ` Robin Murphy
2015-11-04 17:35 ` Laura Abbott
2015-10-01 19:14 ` [PATCH v6 3/3] arm64: Hook up " Robin Murphy
2015-10-13 12:12 ` [PATCH v6 0/3] arm64: IOMMU-backed DMA mapping Robin Murphy
2015-10-14 11:50 ` joro at 8bytes.org
2015-10-14 18:19 ` Robin Murphy
2015-10-15 15:04 ` Joerg Roedel
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