[PATCH v2 1/2] powerpc/pci: convert to use for_each_pci_bridge() helper

[PATCH v2 1/2] powerpc/pci: convert to use for_each_pci_bridge() helper

[Andy Shevchenko]

...which makes code slightly cleaner.

Requires: d43f59ce6c50 ("PCI: Add for_each_pci_bridge() helper")
Acked-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
---
 arch/powerpc/kernel/pci-hotplug.c | 7 ++-----
 arch/powerpc/kernel/pci_of_scan.c | 7 ++-----
 2 files changed, 4 insertions(+), 10 deletions(-)

diff --git a/arch/powerpc/kernel/pci-hotplug.c b/arch/powerpc/kernel/pci-hotplug.c
index 2d71269e7dc1..741f47295188 100644
--- a/arch/powerpc/kernel/pci-hotplug.c
+++ b/arch/powerpc/kernel/pci-hotplug.c
@@ -134,11 +134,8 @@ void pci_hp_add_devices(struct pci_bus *bus)
 		pcibios_setup_bus_devices(bus);
 		max = bus->busn_res.start;
 		for (pass = 0; pass < 2; pass++) {
-			list_for_each_entry(dev, &bus->devices, bus_list) {
-				if (pci_is_bridge(dev))
-					max = pci_scan_bridge(bus, dev,
-							      max, pass);
-			}
+			for_each_pci_bridge(dev, bus)
+				max = pci_scan_bridge(bus, dev, max, pass);
 		}
 	}
 	pcibios_finish_adding_to_bus(bus);
diff --git a/arch/powerpc/kernel/pci_of_scan.c b/arch/powerpc/kernel/pci_of_scan.c
index 0d790f8432d2..8bdaa2a6fa62 100644
--- a/arch/powerpc/kernel/pci_of_scan.c
+++ b/arch/powerpc/kernel/pci_of_scan.c
@@ -369,11 +369,8 @@ static void __of_scan_bus(struct device_node *node, struct pci_bus *bus,
 	pcibios_setup_bus_devices(bus);
 
 	/* Now scan child busses */
-	list_for_each_entry(dev, &bus->devices, bus_list) {
-		if (pci_is_bridge(dev)) {
-			of_scan_pci_bridge(dev);
-		}
-	}
+	for_each_pci_bridge(dev, bus)
+		of_scan_pci_bridge(dev);
 }
 
 /**
-- 
2.14.2

[PATCH v2 2/2] powerpc/pci: Unroll two pass loop when scanning bridges

[Andy Shevchenko]

The current scanning code is really hard to understand because it calls
the same function in a loop where pass value is changed without any
comments explaining it:

  for (pass = 0; pass < 2; pass++)
    for_each_pci_bridge(dev, bus)
      max = pci_scan_bridge(bus, dev, max, pass);

Unfamiliar reader cannot tell easily what is the purpose of this loop
without looking at internals of pci_scan_bridge().

In order to make this bit easier to understand, open-code the loop in
pci_scan_child_bus() and pci_hp_add_bridge() with added comments.

No functional changes intended.

Cc: Mika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
---
 arch/powerpc/kernel/pci-hotplug.c | 17 ++++++++++++-----
 1 file changed, 12 insertions(+), 5 deletions(-)

diff --git a/arch/powerpc/kernel/pci-hotplug.c b/arch/powerpc/kernel/pci-hotplug.c
index 741f47295188..cf47b1aec4c2 100644
--- a/arch/powerpc/kernel/pci-hotplug.c
+++ b/arch/powerpc/kernel/pci-hotplug.c
@@ -104,7 +104,7 @@ EXPORT_SYMBOL_GPL(pci_hp_remove_devices);
  */
 void pci_hp_add_devices(struct pci_bus *bus)
 {
-	int slotno, mode, pass, max;
+	int slotno, mode, max;
 	struct pci_dev *dev;
 	struct pci_controller *phb;
 	struct device_node *dn = pci_bus_to_OF_node(bus);
@@ -133,10 +133,17 @@ void pci_hp_add_devices(struct pci_bus *bus)
 		pci_scan_slot(bus, PCI_DEVFN(slotno, 0));
 		pcibios_setup_bus_devices(bus);
 		max = bus->busn_res.start;
-		for (pass = 0; pass < 2; pass++) {
-			for_each_pci_bridge(dev, bus)
-				max = pci_scan_bridge(bus, dev, max, pass);
-		}
+		/*
+		 * Scan bridges that are already configured. We don't touch
+		 * them unless they are misconfigured (which will be done in
+		 * the second scan below).
+		 */
+		for_each_pci_bridge(dev, bus)
+			max = pci_scan_bridge(bus, dev, max, 0);
+
+		/* Scan bridges that need to be reconfigured */
+		for_each_pci_bridge(dev, bus)
+			max = pci_scan_bridge(bus, dev, max, 1);
 	}
 	pcibios_finish_adding_to_bus(bus);
 }
-- 
2.14.2

Re: [PATCH v2 2/2] powerpc/pci: Unroll two pass loop when scanning bridges

[Mika Westerberg]

On Fri, Nov 10, 2017 at 07:52:30PM +0200, Andy Shevchenko wrote:
> The current scanning code is really hard to understand because it calls
> the same function in a loop where pass value is changed without any
> comments explaining it:
> 
>   for (pass = 0; pass < 2; pass++)
>     for_each_pci_bridge(dev, bus)
>       max = pci_scan_bridge(bus, dev, max, pass);
> 
> Unfamiliar reader cannot tell easily what is the purpose of this loop
> without looking at internals of pci_scan_bridge().
> 
> In order to make this bit easier to understand, open-code the loop in
> pci_scan_child_bus() and pci_hp_add_bridge() with added comments.
> 
> No functional changes intended.
> 
> Cc: Mika Westerberg <mika.westerberg@linux.intel.com>

Reviewed-by: Mika Westerberg <mika.westerberg@linux.intel.com>

Re: [PATCH v2 1/2] powerpc/pci: convert to use for_each_pci_bridge() helper

[Bjorn Helgaas]

On Fri, Nov 10, 2017 at 07:52:29PM +0200, Andy Shevchenko wrote:
> ...which makes code slightly cleaner.
> 
> Requires: d43f59ce6c50 ("PCI: Add for_each_pci_bridge() helper")

Requires: 24a0c654d7d6 ("PCI: Add for_each_pci_bridge() helper")

(My fault, I rebased that commit before sending it to Linus.)

> Acked-by: Michael Ellerman <mpe@ellerman.id.au>

These don't depend on anything in the PCI core, so they could go
either via my tree or the powerpc tree.  Since you acked this,
Michael, I corrected the SHA1 above and put these both on my pci/misc
branch.

If you pick them up, let me know and I'll drop them from my tree.

> Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
> ---
>  arch/powerpc/kernel/pci-hotplug.c | 7 ++-----
>  arch/powerpc/kernel/pci_of_scan.c | 7 ++-----
>  2 files changed, 4 insertions(+), 10 deletions(-)
> 
> diff --git a/arch/powerpc/kernel/pci-hotplug.c b/arch/powerpc/kernel/pci-hotplug.c
> index 2d71269e7dc1..741f47295188 100644
> --- a/arch/powerpc/kernel/pci-hotplug.c
> +++ b/arch/powerpc/kernel/pci-hotplug.c
> @@ -134,11 +134,8 @@ void pci_hp_add_devices(struct pci_bus *bus)
>  		pcibios_setup_bus_devices(bus);
>  		max = bus->busn_res.start;
>  		for (pass = 0; pass < 2; pass++) {
> -			list_for_each_entry(dev, &bus->devices, bus_list) {
> -				if (pci_is_bridge(dev))
> -					max = pci_scan_bridge(bus, dev,
> -							      max, pass);
> -			}
> +			for_each_pci_bridge(dev, bus)
> +				max = pci_scan_bridge(bus, dev, max, pass);
>  		}
>  	}
>  	pcibios_finish_adding_to_bus(bus);
> diff --git a/arch/powerpc/kernel/pci_of_scan.c b/arch/powerpc/kernel/pci_of_scan.c
> index 0d790f8432d2..8bdaa2a6fa62 100644
> --- a/arch/powerpc/kernel/pci_of_scan.c
> +++ b/arch/powerpc/kernel/pci_of_scan.c
> @@ -369,11 +369,8 @@ static void __of_scan_bus(struct device_node *node, struct pci_bus *bus,
>  	pcibios_setup_bus_devices(bus);
>  
>  	/* Now scan child busses */
> -	list_for_each_entry(dev, &bus->devices, bus_list) {
> -		if (pci_is_bridge(dev)) {
> -			of_scan_pci_bridge(dev);
> -		}
> -	}
> +	for_each_pci_bridge(dev, bus)
> +		of_scan_pci_bridge(dev);
>  }
>  
>  /**
> -- 
> 2.14.2
> 

Re: [PATCH v2 1/2] powerpc/pci: convert to use for_each_pci_bridge() helper

[Michael Ellerman]

Bjorn Helgaas <helgaas@kernel.org> writes:

> On Fri, Nov 10, 2017 at 07:52:29PM +0200, Andy Shevchenko wrote:
>> ...which makes code slightly cleaner.
>> 
>> Requires: d43f59ce6c50 ("PCI: Add for_each_pci_bridge() helper")
>
> Requires: 24a0c654d7d6 ("PCI: Add for_each_pci_bridge() helper")
>
> (My fault, I rebased that commit before sending it to Linus.)
>
>> Acked-by: Michael Ellerman <mpe@ellerman.id.au>
>
> These don't depend on anything in the PCI core, so they could go
> either via my tree or the powerpc tree.  Since you acked this,
> Michael, I corrected the SHA1 above and put these both on my pci/misc
> branch.

Thanks. That's aiming for 4.16 I assume?

cheers

Re: [PATCH v2 1/2] powerpc/pci: convert to use for_each_pci_bridge() helper

[Bjorn Helgaas]

On Thu, Nov 23, 2017 at 11:48:18PM +1100, Michael Ellerman wrote:
> Bjorn Helgaas <helgaas@kernel.org> writes:
> 
> > On Fri, Nov 10, 2017 at 07:52:29PM +0200, Andy Shevchenko wrote:
> >> ...which makes code slightly cleaner.
> >> 
> >> Requires: d43f59ce6c50 ("PCI: Add for_each_pci_bridge() helper")
> >
> > Requires: 24a0c654d7d6 ("PCI: Add for_each_pci_bridge() helper")
> >
> > (My fault, I rebased that commit before sending it to Linus.)
> >
> >> Acked-by: Michael Ellerman <mpe@ellerman.id.au>
> >
> > These don't depend on anything in the PCI core, so they could go
> > either via my tree or the powerpc tree.  Since you acked this,
> > Michael, I corrected the SHA1 above and put these both on my pci/misc
> > branch.
> 
> Thanks. That's aiming for 4.16 I assume?

Right.