[PATCH V8 07/11] iommu: of: Handle IOMMU lookup failure with deferred probing or error

diff --git a/drivers/iommu/of_iommu.c b/drivers/iommu/of_iommu.c
index 9f44ee8..e6e9bec 100644
--- a/drivers/iommu/of_iommu.c
+++ b/drivers/iommu/of_iommu.c

@@ -118,6 +118,7 @@ static bool of_iommu_driver_present(struct device_node *np)

        ops = iommu_ops_from_fwnode(fwnode);
        if ((ops && !ops->of_xlate) ||
+           !of_device_is_available(iommu_spec->np) ||
            (!ops && !of_iommu_driver_present(iommu_spec->np)))
                return NULL;

-- 
QUALCOMM INDIA, on behalf of Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, hosted by The Linux Foundation


Regards,
 Sricharan


> Robin.
> 
>> This can be fixed by either:
>>   - Disabling CONFIG_IPMMU_VMSA, or
>>   - Reverting commit 7b07cbefb68d486f (but keeping "int ret = 0;").
>>
>> Note that this was a bit hard to investigate, as R-Car Gen3 support wasn't
>> upstreamed yet, so bisection pointed to a merge commit.
>>
>>> ---
>>>  [*] Fixed minor comment from Bjorn for removing the pci.h header inclusion
>>>      in of_iommu.c
>>>
>>>  drivers/base/dma-mapping.c | 5 +++--
>>>  drivers/iommu/of_iommu.c   | 4 ++--
>>>  drivers/of/device.c        | 7 ++++++-
>>>  include/linux/of_device.h  | 9 ++++++---
>>>  4 files changed, 17 insertions(+), 8 deletions(-)
>>>
>>> diff --git a/drivers/base/dma-mapping.c b/drivers/base/dma-mapping.c
>>> index 449b948..82bd45c 100644
>>> --- a/drivers/base/dma-mapping.c
>>> +++ b/drivers/base/dma-mapping.c
>>> @@ -353,6 +353,7 @@ int dma_configure(struct device *dev)
>>>  {
>>>         struct device *bridge = NULL, *dma_dev = dev;
>>>         enum dev_dma_attr attr;
>>> +       int ret = 0;
>>>
>>>         if (dev_is_pci(dev)) {
>>>                 bridge = pci_get_host_bridge_device(to_pci_dev(dev));
>>> @@ -363,7 +364,7 @@ int dma_configure(struct device *dev)
>>>         }
>>>
>>>         if (dma_dev->of_node) {
>>> -               of_dma_configure(dev, dma_dev->of_node);
>>> +               ret = of_dma_configure(dev, dma_dev->of_node);
>>>         } else if (has_acpi_companion(dma_dev)) {
>>>                 attr = acpi_get_dma_attr(to_acpi_device_node(dma_dev->fwnode));
>>>                 if (attr != DEV_DMA_NOT_SUPPORTED)
>>> @@ -373,7 +374,7 @@ int dma_configure(struct device *dev)
>>>         if (bridge)
>>>                 pci_put_host_bridge_device(bridge);
>>>
>>> -       return 0;
>>> +       return ret;
>>>  }
>>>
>>>  void dma_deconfigure(struct device *dev)
>>> diff --git a/drivers/iommu/of_iommu.c b/drivers/iommu/of_iommu.c
>>> index 1f92d98..2d04663 100644
>>> --- a/drivers/iommu/of_iommu.c
>>> +++ b/drivers/iommu/of_iommu.c
>>> @@ -236,7 +236,7 @@ const struct iommu_ops *of_iommu_configure(struct device *dev,
>>>                         ops = ERR_PTR(err);
>>>         }
>>>
>>> -       return IS_ERR(ops) ? NULL : ops;
>>> +       return ops;
>>>  }
>>>
>>>  static int __init of_iommu_init(void)
>>> @@ -247,7 +247,7 @@ static int __init of_iommu_init(void)
>>>         for_each_matching_node_and_match(np, matches, &match) {
>>>                 const of_iommu_init_fn init_fn = match->data;
>>>
>>> -               if (init_fn(np))
>>> +               if (init_fn && init_fn(np))
>>>                         pr_err("Failed to initialise IOMMU %s\n",
>>>                                 of_node_full_name(np));
>>>         }
>>> diff --git a/drivers/of/device.c b/drivers/of/device.c
>>> index c17c19d..ba51ca6 100644
>>> --- a/drivers/of/device.c
>>> +++ b/drivers/of/device.c
>>> @@ -82,7 +82,7 @@ int of_device_add(struct platform_device *ofdev)
>>>   * can use a platform bus notifier and handle BUS_NOTIFY_ADD_DEVICE events
>>>   * to fix up DMA configuration.
>>>   */
>>> -void of_dma_configure(struct device *dev, struct device_node *np)
>>> +int of_dma_configure(struct device *dev, struct device_node *np)
>>>  {
>>>         u64 dma_addr, paddr, size;
>>>         int ret;
>>> @@ -129,10 +129,15 @@ void of_dma_configure(struct device *dev, struct device_node *np)
>>>                 coherent ? " " : " not ");
>>>
>>>         iommu = of_iommu_configure(dev, np);
>>> +       if (IS_ERR(iommu))
>>> +               return PTR_ERR(iommu);
>>> +
>>>         dev_dbg(dev, "device is%sbehind an iommu\n",
>>>                 iommu ? " " : " not ");
>>>
>>>         arch_setup_dma_ops(dev, dma_addr, size, iommu, coherent);
>>> +
>>> +       return 0;
>>>  }
>>>  EXPORT_SYMBOL_GPL(of_dma_configure);
>>>
>>> diff --git a/include/linux/of_device.h b/include/linux/of_device.h
>>> index 3cb2288..9499861 100644
>>> --- a/include/linux/of_device.h
>>> +++ b/include/linux/of_device.h
>>> @@ -56,7 +56,7 @@ static inline struct device_node *of_cpu_device_node_get(int cpu)
>>>         return of_node_get(cpu_dev->of_node);
>>>  }
>>>
>>> -void of_dma_configure(struct device *dev, struct device_node *np);
>>> +int of_dma_configure(struct device *dev, struct device_node *np);
>>>  void of_dma_deconfigure(struct device *dev);
>>>  #else /* CONFIG_OF */
>>>
>>> @@ -105,8 +105,11 @@ static inline struct device_node *of_cpu_device_node_get(int cpu)
>>>  {
>>>         return NULL;
>>>  }
>>> -static inline void of_dma_configure(struct device *dev, struct device_node *np)
>>> -{}
>>> +
>>> +static inline int of_dma_configure(struct device *dev, struct device_node *np)
>>> +{
>>> +       return 0;
>>> +}
>>>  static inline void of_dma_deconfigure(struct device *dev)
>>>  {}
>>>  #endif /* CONFIG_OF */
>>
>> Gr{oetje,eeting}s,
>>
>>                         Geert
>>
>> --
>> Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert at linux-m68k.org
>>
>> In personal conversations with technical people, I call myself a hacker. But
>> when I'm talking to journalists I just say "programmer" or something like that.
>>                                 -- Linus Torvalds
>>
> 

-- 
"QUALCOMM INDIA, on behalf of Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, hosted by The Linux Foundation