On Mon, Sep 08, 2014 at 04:59:31PM +0100, Liviu Dudau wrote:

On Mon, Sep 08, 2014 at 04:27:36PM +0100, Rob Herring wrote:

quoted

On Mon, Sep 8, 2014 at 9:54 AM, Liviu Dudau [off-list ref] wrote:

quoted

On Mon, Sep 08, 2014 at 03:27:56PM +0100, Rob Herring wrote:

quoted

On Mon, Sep 8, 2014 at 8:54 AM, Liviu Dudau [off-list ref] wrote:

quoted

Add of_pci_get_domain_nr() to retrieve the PCI domain number
of a given device from DT. If the information is not present,
the function can be requested to allocate a new domain number.

Cc: Bjorn Helgaas <bhelgaas@google.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Grant Likely <redacted>
Cc: Rob Herring <robh+dt@kernel.org>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Liviu Dudau <Liviu.Dudau@arm.com>
---
 drivers/of/of_pci.c    | 34 ++++++++++++++++++++++++++++++++++
 include/linux/of_pci.h |  7 +++++++
 2 files changed, 41 insertions(+)

diff --git a/drivers/of/of_pci.c b/drivers/of/of_pci.c
index 8481996..a107edb 100644
--- a/drivers/of/of_pci.c
+++ b/drivers/of/of_pci.c

@@ -89,6 +89,40 @@ int of_pci_parse_bus_range(struct device_node *node, struct resource *res)
 }
 EXPORT_SYMBOL_GPL(of_pci_parse_bus_range);

+static atomic_t of_domain_nr = ATOMIC_INIT(-1);
+
+/**
+ * This function will try to obtain the host bridge domain number by
+ * using of_alias_get_id() call with "pci-domain" as a stem. If that
+ * fails, a local allocator will be used. The local allocator can
+ * be requested to return a new domain_nr if the information is missing
+ * from the device tree.
+ *
+ * @node: device tree node with the domain information
+ * @allocate_if_missing: if DT lacks information about the domain nr,
+ * allocate a new number.
+ *
+ * Returns the associated domain number from DT, or a new domain number
+ * if DT information is missing and @allocate_if_missing is true. If
+ * @allocate_if_missing is false then the last allocated domain number
+ * will be returned.
+ */
+int of_pci_get_domain_nr(struct device_node *node, bool allocate_if_missing)
+{
+       int domain;
+
+       domain = of_alias_get_id(node, "pci-domain");
+       if (domain == -ENODEV) {
+               if (allocate_if_missing)
+                       domain = atomic_inc_return(&of_domain_nr);
+               else
+                       domain = atomic_read(&of_domain_nr);

This function seems a bit broken to me. It is overloaded with too many
different outcomes. Think about how this would work if you have
multiple PCI buses and a mixture of having pci-domain aliases or not.
Aren't domain numbers global? Allocation should then start outside of
the range of alias ids.

Rob

Rob,

Would this version make more sense?

No.

Hi Rob,

Here is an updated version of the patch. I have implemented a separate function
for getting the max domain number from the device tree and use the result as
the start value + 1 for the allocator.

Best regards,
Liviu

-- 
====================
| I would like to |
| fix the world,  |
| but they're not |
| giving me the   |
 \ source code!  /
  ---------------
    ?\_(?)_/?
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