Subject: [PATCH v2 3/7] of/irq: Break out msi-map lookup (again)

From: [email-masked] (Robin Murphy)
Date: Wed, 15 Jun 2016 11:16:16 +0100

On 14/06/16 18:01, Rob Herring wrote:
> On Fri, Jun 3, 2016 at 12:15 PM, Robin Murphy <[email-masked]> wrote:
>> The PCI msi-map code is already doing double-duty translating IDs and
>> retrieving MSI parents, which unsurprisingly is the same functionality
>> we need for the identically-formatted PCI iommu-map property. Drag the
>> core parsing routine up yet another layer into the general OF-PCI code,
>> and further generalise it for either kind of lookup in either flavour
>> of map property.
>>
>> CC: Rob Herring <[email-masked]>
>> CC: Frank Rowand <[email-masked]>
>> CC: Marc Zyngier <[email-masked]>
>> Signed-off-by: Robin Murphy <[email-masked]>
>> ---
>>
>> v2: No change.
>>
>>   drivers/of/irq.c       |  70 ++-------------------------------
>>   drivers/of/of_pci.c    | 102 +++++++++++++++++++++++++++++++++++++++++++++++++
>>   include/linux/of_pci.h |   8 ++++
>>   3 files changed, 114 insertions(+), 66 deletions(-)
>>
>> diff --git a/drivers/of/irq.c b/drivers/of/irq.c
>> index e7bfc175b8e1..0c9118d849ee 100644
>> --- a/drivers/of/irq.c
>> +++ b/drivers/of/irq.c
>> @@ -24,6 +24,7 @@
>>   #include <linux/module.h>
>>   #include <linux/of.h>
>>   #include <linux/of_irq.h>
>> +#include <linux/of_pci.h>
>>   #include <linux/string.h>
>>   #include <linux/slab.h>
>>
>> @@ -586,13 +587,7 @@ static u32 __of_msi_map_rid(struct device *dev, struct device_node **np,
>>                              u32 rid_in)
>>   {
>>          struct device *parent_dev;
>> -       struct device_node *msi_controller_node;
>> -       struct device_node *msi_np = *np;
>> -       u32 map_mask, masked_rid, rid_base, msi_base, rid_len, phandle;
>> -       int msi_map_len;
>> -       bool matched;
>>          u32 rid_out = rid_in;
>> -       const __be32 *msi_map = NULL;
>>
>>          /*
>>           * Walk up the device parent links looking for one with a
>> @@ -602,71 +597,14 @@ static u32 __of_msi_map_rid(struct device *dev, struct device_node **np,
>>                  if (!parent_dev->of_node)
>>                          continue;
>>
>> -               msi_map = of_get_property(parent_dev->of_node,
>> -                                         "msi-map", &msi_map_len);
>> -               if (!msi_map)
>> +               if (!of_property_read_bool(parent_dev->of_node, "msi-map"))
>
> But msi-map is not bool, right? I think we allow bools to have values
> for historical reasons, but really bool with a value should be an
> error. So don't rely on current behavior.

Right, I now have no idea why that wasn't of_find_property() in the 
first place...

>>                          continue;
>>
>> -               if (msi_map_len % (4 * sizeof(__be32))) {
>> -                       dev_err(parent_dev, "Error: Bad msi-map length: %d\n",
>> -                               msi_map_len);
>> -                       return rid_out;
>> -               }
>>                  /* We have a good parent_dev and msi_map, let's use them. */
>> +               of_pci_map_rid(parent_dev->of_node, "msi-map", rid_in, np,
>> +                              &rid_out);
>
> Seems like this could return an error code and then you could continue
> based on the return code. Then you wouldn't be looking up msi-map
> twice. Probably could get rid of the !parent_dev->of_node check too.

...but I agree that approach does sound better overall, so I'll take a 
closer look at this whole patch again.

Thanks,
Robin.

> Rob