From: laurent.pinchart@ideasonboard.com (Laurent Pinchart)
To: linux-arm-kernel@lists.infradead.org
Subject: [RFC PATCH v2 4/7] iommu: provide helper function to configure an IOMMU for an of master
Date: Wed, 10 Sep 2014 16:01:34 +0300 [thread overview]
Message-ID: <1486715.2XVviDPC9Z@avalon> (raw)
In-Reply-To: <1409680587-29818-5-git-send-email-will.deacon@arm.com>
Hi Will,
Thank you for the patch.
On Tuesday 02 September 2014 18:56:24 Will Deacon wrote:
> The generic IOMMU device-tree bindings can be used to add arbitrary OF
> masters to an IOMMU with a compliant binding.
>
> This patch introduces of_iommu_configure, which does exactly that.
>
> Signed-off-by: Will Deacon <will.deacon@arm.com>
> ---
> drivers/iommu/Kconfig | 2 +-
> drivers/iommu/of_iommu.c | 52 ++++++++++++++++++++++++++++++++++++++++++
> include/linux/dma-mapping.h | 7 ++++++
> include/linux/of_iommu.h | 8 +++++++
> 4 files changed, 68 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/iommu/Kconfig b/drivers/iommu/Kconfig
> index dd5112265cc9..6d13f962f156 100644
> --- a/drivers/iommu/Kconfig
> +++ b/drivers/iommu/Kconfig
> @@ -15,7 +15,7 @@ if IOMMU_SUPPORT
>
> config OF_IOMMU
> def_bool y
> - depends on OF
> + depends on OF && IOMMU_API
>
> config FSL_PAMU
> bool "Freescale IOMMU support"
> diff --git a/drivers/iommu/of_iommu.c b/drivers/iommu/of_iommu.c
> index f9209666157c..1188c929ffa7 100644
> --- a/drivers/iommu/of_iommu.c
> +++ b/drivers/iommu/of_iommu.c
> @@ -18,6 +18,7 @@
> */
>
> #include <linux/export.h>
> +#include <linux/iommu.h>
> #include <linux/limits.h>
> #include <linux/of.h>
> #include <linux/of_iommu.h>
> @@ -90,6 +91,57 @@ int of_get_dma_window(struct device_node *dn, const char
> *prefix, int index, }
> EXPORT_SYMBOL_GPL(of_get_dma_window);
>
> +struct iommu_dma_mapping *of_iommu_configure(struct device *dev)
> +{
> + struct of_phandle_args iommu_spec;
> + struct iommu_dma_mapping *mapping;
> + struct bus_type *bus = dev->bus;
> + const struct iommu_ops *ops = bus->iommu_ops;
> + struct iommu_data *iommu = NULL;
> + int idx = 0;
> +
> + if (!iommu_present(bus) || !ops->of_xlate)
> + return NULL;
> +
> + /*
> + * We don't currently walk up the tree looking for a parent IOMMU.
> + * See the `Notes:' section of
> + * Documentation/devicetree/bindings/iommu/iommu.txt
> + */
> + while (!of_parse_phandle_with_args(dev->of_node, "iommus",
> + "#iommu-cells", idx,
> + &iommu_spec)) {
> + struct device_node *np = iommu_spec.np;
> + struct iommu_data *data = of_iommu_get_data(np);
> +
> + if (!iommu) {
> + if (!ops->of_xlate(dev, &iommu_spec))
> + iommu = data;
If I understand the code correctly, this will call of_xlate for the first
IOMMU reference only and silently ignore all subsequent references if they
point to the same IOMMU device but with different stream/requester IDs. Is
that the desired behaviour ?
> + } else if (iommu != data) {
> + pr_warn("Rejecting device %s with multiple IOMMU instances\n",
> + dev_name(dev));
> + iommu = NULL;
> + }
> +
> + of_node_put(np);
> +
> + if (!iommu)
> + break;
> +
> + idx++;
> + }
> +
> + if (!iommu)
> + return NULL;
> +
> + mapping = devm_kzalloc(dev, sizeof(*mapping), GFP_KERNEL);
> + if (!mapping)
> + return NULL;
> +
> + mapping->iommu = iommu;
> + return mapping;
> +}
> +
> void __init of_iommu_init(void)
> {
> struct device_node *np;
> diff --git a/include/linux/dma-mapping.h b/include/linux/dma-mapping.h
> index 0f7f7b68b0db..16bf92f71c3e 100644
> --- a/include/linux/dma-mapping.h
> +++ b/include/linux/dma-mapping.h
> @@ -62,6 +62,13 @@ struct dma_map_ops {
> int is_phys;
> };
>
> +struct iommu_data;
> +
> +struct iommu_dma_mapping {
> + struct iommu_data *iommu;
> + struct list_head node;
> +};
> +
> #define DMA_BIT_MASK(n) (((n) == 64) ? ~0ULL : ((1ULL<<(n))-1))
>
> #define DMA_MASK_NONE 0x0ULL
> diff --git a/include/linux/of_iommu.h b/include/linux/of_iommu.h
> index a39e2d78f735..f2d3b1e780d7 100644
> --- a/include/linux/of_iommu.h
> +++ b/include/linux/of_iommu.h
> @@ -1,9 +1,12 @@
> #ifndef __OF_IOMMU_H
> #define __OF_IOMMU_H
>
> +#include <linux/device.h>
> #include <linux/iommu.h>
> #include <linux/of.h>
>
> +struct iommu_dma_mapping;
> +
> #ifdef CONFIG_OF_IOMMU
>
> extern int of_get_dma_window(struct device_node *dn, const char *prefix,
> @@ -11,6 +14,7 @@ extern int of_get_dma_window(struct device_node *dn, const
> char *prefix, size_t *size);
>
> extern void of_iommu_init(void);
> +extern struct iommu_dma_mapping *of_iommu_configure(struct device *dev);
>
> #else
>
> @@ -22,6 +26,10 @@ static inline int of_get_dma_window(struct device_node
> *dn, const char *prefix, }
>
> static inline void of_iommu_init(void) { }
> +static inline struct iommu_dma_mapping *of_iommu_configure(struct device
> *dev) +{
> + return NULL;
> +}
>
> #endif /* CONFIG_OF_IOMMU */
--
Regards,
Laurent Pinchart
next prev parent reply other threads:[~2014-09-10 13:01 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-09-02 17:56 [RFC PATCH v2 0/7] Introduce automatic DMA configuration for IOMMU masters Will Deacon
2014-09-02 17:56 ` [RFC PATCH v2 1/7] iommu: provide early initialisation hook for IOMMU drivers Will Deacon
2014-09-10 11:29 ` Marek Szyprowski
2014-09-02 17:56 ` [RFC PATCH v2 2/7] dma-mapping: replace set_arch_dma_coherent_ops with arch_setup_dma_ops Will Deacon
2014-09-05 15:37 ` Grygorii Strashko
2014-09-08 10:31 ` Will Deacon
2014-09-09 14:15 ` Grygorii Strashko
2014-09-02 17:56 ` [RFC PATCH v2 3/7] iommu: add new iommu_ops callback for adding an OF device Will Deacon
2014-09-10 11:16 ` Marek Szyprowski
2014-09-10 11:22 ` Will Deacon
2014-09-10 11:33 ` Will Deacon
2014-09-02 17:56 ` [RFC PATCH v2 4/7] iommu: provide helper function to configure an IOMMU for an of master Will Deacon
2014-09-02 19:10 ` Arnd Bergmann
2014-09-04 11:26 ` Will Deacon
2014-09-04 11:59 ` Arnd Bergmann
2014-09-04 12:28 ` Will Deacon
2014-09-10 13:01 ` Laurent Pinchart [this message]
2014-09-10 13:06 ` Will Deacon
2014-09-02 17:56 ` [RFC PATCH v2 5/7] dma-mapping: detect and configure IOMMU in of_dma_configure Will Deacon
2014-09-02 17:56 ` [RFC PATCH v2 6/7] arm: call iommu_init before of_platform_populate Will Deacon
2014-09-02 18:13 ` Arnd Bergmann
2014-09-02 17:56 ` [RFC PATCH v2 7/7] arm: dma-mapping: plumb our iommu mapping ops into arch_setup_dma_ops Will Deacon
2014-09-02 18:14 ` Arnd Bergmann
2014-09-02 19:11 ` [RFC PATCH v2 0/7] Introduce automatic DMA configuration for IOMMU masters Arnd Bergmann
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