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:
> > On Mon, Sep 8, 2014 at 9:54 AM, Liviu Dudau <Liviu.Dudau@xxxxxxx> wrote:
> > > On Mon, Sep 08, 2014 at 03:27:56PM +0100, Rob Herring wrote:
> > >> On Mon, Sep 8, 2014 at 8:54 AM, Liviu Dudau <Liviu.Dudau@xxxxxxx> wrote:
> > >> > 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@xxxxxxxxxx>
> > >> > Cc: Arnd Bergmann <arnd@xxxxxxxx>
> > >> > Cc: Grant Likely <grant.likely@xxxxxxxxxx>
> > >> > Cc: Rob Herring <robh+dt@xxxxxxxxxx>
> > >> > Reviewed-by: Catalin Marinas <catalin.marinas@xxxxxxx>
> > >> > Signed-off-by: Liviu Dudau <Liviu.Dudau@xxxxxxx>
> > >> > ---
> > >> > 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! /
---------------
¯\_(ツ)_/¯>From 77257fceaa8fbd74d6132fcf57c3af14bd48c0ae Mon Sep 17 00:00:00 2001
From: Liviu Dudau <Liviu.Dudau@xxxxxxx>
Date: Mon, 4 Aug 2014 17:03:04 +0100
Subject: [PATCH v10 07/10] OF: Introduce helper function for getting PCI domain_nr
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@xxxxxxxxxx>
Cc: Arnd Bergmann <arnd@xxxxxxxx>
Cc: Grant Likely <grant.likely@xxxxxxxxxx>
Cc: Rob Herring <robh+dt@xxxxxxxxxx>
Reviewed-by: Catalin Marinas <catalin.marinas@xxxxxxx>
Signed-off-by: Liviu Dudau <Liviu.Dudau@xxxxxxx>
---
drivers/of/of_pci.c | 62 ++++++++++++++++++++++++++++++++++++++++++++++++++
include/linux/of_pci.h | 7 ++++++
2 files changed, 69 insertions(+)
diff --git a/drivers/of/of_pci.c b/drivers/of/of_pci.c
index 8481996..3560401 100644
--- a/drivers/of/of_pci.c
+++ b/drivers/of/of_pci.c
@@ -3,6 +3,8 @@
#include <linux/of.h>
#include <linux/of_pci.h>
+#include "of_private.h"
+
static inline int __of_pci_pci_compare(struct device_node *node,
unsigned int data)
{
@@ -89,6 +91,66 @@ 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);
+
+/*
+ * Get the maximum value for a domain number from the device tree
+ */
+static int of_get_max_pci_domain_nr(void)
+{
+ struct alias_prop *app;
+ int max_domain = -1;
+
+ mutex_lock(&of_mutex);
+ list_for_each_entry(app, &aliases_lookup, link) {
+ if (strncmp(app->stem, "pci-domain", 10) != 0)
+ continue;
+
+ max_domain = max(max_domain, app->id);
+ }
+ mutex_unlock(&of_mutex);
+
+ return max_domain;
+}
+
+/**
+ * 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 = atomic_read(&of_domain_nr);
+ if (of_domain_nr == -1) {
+ /* first run, get max defined domain nr in device tree */
+ domain = of_get_max_pci_domain_nr();
+ /* then set the start value for allocator to be max + 1 */
+ atomic_set(&of_domain_nr, domain + 1);
+ }
+ domain = of_alias_get_id(node, "pci-domain");
+ if (domain == -ENODEV) {
+ domain = atomic_read(&of_domain_nr);
+ if (allocate_if_missing)
+ atomic_inc(&of_domain_nr);
+ }
+
+ return domain;
+}
+EXPORT_SYMBOL_GPL(of_pci_get_domain_nr);
+
#ifdef CONFIG_PCI_MSI
static LIST_HEAD(of_pci_msi_chip_list);
diff --git a/include/linux/of_pci.h b/include/linux/of_pci.h
index dde3a4a..3a3824c 100644
--- a/include/linux/of_pci.h
+++ b/include/linux/of_pci.h
@@ -15,6 +15,7 @@ struct device_node *of_pci_find_child_device(struct device_node *parent,
int of_pci_get_devfn(struct device_node *np);
int of_irq_parse_and_map_pci(const struct pci_dev *dev, u8 slot, u8 pin);
int of_pci_parse_bus_range(struct device_node *node, struct resource *res);
+int of_pci_get_domain_nr(struct device_node *node, bool allocate_if_missing);
#else
static inline int of_irq_parse_pci(const struct pci_dev *pdev, struct of_phandle_args *out_irq)
{
@@ -43,6 +44,12 @@ of_pci_parse_bus_range(struct device_node *node, struct resource *res)
{
return -EINVAL;
}
+
+static inline int
+of_pci_get_domain_nr(struct device_node *node, bool allocate_if_missing)
+{
+ return -1;
+}
#endif
#if defined(CONFIG_OF) && defined(CONFIG_PCI_MSI)
--
2.0.4
