[PATCH 0/2] Translate of PCI address without PCI enabled

[PATCH 0/2] Translate of PCI address without PCI enabled

[Gregory CLEMENT]

Hello,

This patch set makes the use of the of PCI address translator less
restrictive. At the end it will allow to use the mvebu_get_soc_id
unconditionally.

The mvebu SoC (such as Kirkwood, Dove or Armada XP for instance) come
with an IP of a PCI controller. The ID and the revision of a SoC are
stored in the registers of this controller. Being able to get this
information allows to deals with errata more dynamically.

To manage to read this information, we need to map the registers, and
for this we need to use the of PCI translator which depend of the PCI
support.

However there are mvebu board without any PCI devices, and where
selecting the PCI support would be useless.

Moreover translating an address from a PCI node of the device-tree
into a CPU physical address doesn't require the core PCI
support. Those translations are just related to the device tree
itself.

The 1st patch introduces a new config symbol: OF_ADDRESS_PCI, which
will be selected as soon as PCI will be selected, so we remains in the
same situation the current code. It should go to the of tree.

The 2nd patch selects OF_ADDRESS_PCI as soon as ARCH_MVEBU will be
selected. This will make mvebu_get_soc_id available even without the
PCI support. It should go to the mvebu tree.

Thanks,

Gregory CLEMENT (2):
  of: Allows to use the PCI translator without the PCI core
  ARM: mvebu: Allows to get the SoC ID even without PCI enabled

 arch/arm/mach-mvebu/Kconfig | 1 +
 drivers/of/Kconfig          | 4 ++++
 drivers/of/address.c        | 8 +++++---
 3 files changed, 10 insertions(+), 3 deletions(-)

-- 
1.8.1.2

[PATCH 1/2] of: Allows to use the PCI translator without the PCI core

[Gregory CLEMENT]

Translating an address from a PCI node of the device-tree into a CPU
physical address doesn't require the core PCI support. Those
translations are just related to the device tree itself.

The use case to translate an address from a PCI node without actually
using the PCI core support is when one needs to access the PCI
controller without accessing any PCI devices.

Marvell SoCs, such as Kirkwood, Dove or Armada XP for instance, come
with an IP of a PCI controller. In the registers of this controller
are stored the ID and the revision of a SoC. With this patch it will
be possible to read the SoC ID of a board without any PCI device and
then without the PCI core support.

Signed-off-by: Gregory CLEMENT <gregory.clement@free-electrons.com>
---
 drivers/of/Kconfig   | 4 ++++
 drivers/of/address.c | 8 +++++---
 2 files changed, 9 insertions(+), 3 deletions(-)

diff --git a/drivers/of/Kconfig b/drivers/of/Kconfig
index c6973f101a3e..ffdcb11f75fb 100644
--- a/drivers/of/Kconfig
+++ b/drivers/of/Kconfig
@@ -44,6 +44,10 @@ config OF_DYNAMIC
 config OF_ADDRESS
 	def_bool y
 	depends on !SPARC
+	select OF_ADDRESS_PCI if PCI
+
+config OF_ADDRESS_PCI
+	bool
 
 config OF_IRQ
 	def_bool y
diff --git a/drivers/of/address.c b/drivers/of/address.c
index 1a54f1ffaadb..cb4242a69cd5 100644
--- a/drivers/of/address.c
+++ b/drivers/of/address.c
@@ -91,7 +91,7 @@ static unsigned int of_bus_default_get_flags(const __be32 *addr)
 	return IORESOURCE_MEM;
 }
 
-#ifdef CONFIG_PCI
+#ifdef CONFIG_OF_ADDRESS_PCI
 /*
  * PCI bus specific translator
  */
@@ -166,7 +166,9 @@ static int of_bus_pci_translate(__be32 *addr, u64 offset, int na)
 {
 	return of_bus_default_translate(addr + 1, offset, na - 1);
 }
+#endif /* CONFIG_OF_ADDRESS_PCI */
 
+#ifdef CONFIG_PCI
 const __be32 *of_get_pci_address(struct device_node *dev, int bar_no, u64 *size,
 			unsigned int *flags)
 {
@@ -356,7 +358,7 @@ static unsigned int of_bus_isa_get_flags(const __be32 *addr)
  */
 
 static struct of_bus of_busses[] = {
-#ifdef CONFIG_PCI
+#ifdef CONFIG_OF_ADDRESS_PCI
 	/* PCI */
 	{
 		.name = "pci",
@@ -367,7 +369,7 @@ static struct of_bus of_busses[] = {
 		.translate = of_bus_pci_translate,
 		.get_flags = of_bus_pci_get_flags,
 	},
-#endif /* CONFIG_PCI */
+#endif /* CONFIG_OF_ADDRESS_PCI */
 	/* ISA */
 	{
 		.name = "isa",
-- 
1.8.1.2

[PATCH 2/2] ARM: mvebu: Allows to get the SoC ID even without PCI enabled

[Gregory CLEMENT]

The address translation of a PCI node don't require anymore the PCI
support in the kernel. This translation is mandatory to be able to
read the SoC ID which is stored in the PCI controller of the mvebu
SoCs.

This patch selects the symbol needed to get only this translation for
all the mvebu platforms.

Signed-off-by: Gregory CLEMENT <gregory.clement@free-electrons.com>
---
 arch/arm/mach-mvebu/Kconfig | 1 +
 1 file changed, 1 insertion(+)

diff --git a/arch/arm/mach-mvebu/Kconfig b/arch/arm/mach-mvebu/Kconfig
index 5e269d7263ce..df9e7d270810 100644
--- a/arch/arm/mach-mvebu/Kconfig
+++ b/arch/arm/mach-mvebu/Kconfig
@@ -16,6 +16,7 @@ config ARCH_MVEBU
 	select ARCH_REQUIRE_GPIOLIB
 	select MIGHT_HAVE_PCI
 	select PCI_QUIRKS if PCI
+	select OF_ADDRESS_PCI
 
 if ARCH_MVEBU
 
-- 
1.8.1.2

Re: [PATCH 0/2] Translate of PCI address without PCI enabled

[Ezequiel Garcia]

On Wed, Feb 19, 2014 at 11:14:54PM +0100, Gregory CLEMENT wrote:
> Hello,
> 
> This patch set makes the use of the of PCI address translator less
> restrictive. At the end it will allow to use the mvebu_get_soc_id
> unconditionally.
> 
> The mvebu SoC (such as Kirkwood, Dove or Armada XP for instance) come
> with an IP of a PCI controller. The ID and the revision of a SoC are
> stored in the registers of this controller. Being able to get this
> information allows to deals with errata more dynamically.
> 
> To manage to read this information, we need to map the registers, and
> for this we need to use the of PCI translator which depend of the PCI
> support.
> 
> However there are mvebu board without any PCI devices, and where
> selecting the PCI support would be useless.
> 
> Moreover translating an address from a PCI node of the device-tree
> into a CPU physical address doesn't require the core PCI
> support. Those translations are just related to the device tree
> itself.
> 
> The 1st patch introduces a new config symbol: OF_ADDRESS_PCI, which
> will be selected as soon as PCI will be selected, so we remains in the
> same situation the current code. It should go to the of tree.
> 
> The 2nd patch selects OF_ADDRESS_PCI as soon as ARCH_MVEBU will be
> selected. This will make mvebu_get_soc_id available even without the
> PCI support. It should go to the mvebu tree.
> 
> Thanks,
> 
> Gregory CLEMENT (2):
>   of: Allows to use the PCI translator without the PCI core
>   ARM: mvebu: Allows to get the SoC ID even without PCI enabled
> 
>  arch/arm/mach-mvebu/Kconfig | 1 +
>  drivers/of/Kconfig          | 4 ++++
>  drivers/of/address.c        | 8 +++++---
>  3 files changed, 10 insertions(+), 3 deletions(-)
> 
> -- 
> 1.8.1.2
> 

On XP GP and CONFIG_PCI=n, without the patches I get this:

  mvebu-soc-id: cannot map registers

and after applying the patches I have:

  mvebu-soc-id: MVEBU SoC ID=0x7846, Rev=0x2

Tested-by: Ezequiel Garcia <ezequiel.garcia@free-electrons.com>
Reviewed-by: Ezequiel Garcia <ezequiel.garcia@free-electrons.com>

Thanks for taking care of this.
-- 
Ezequiel García, Free Electrons
Embedded Linux, Kernel and Android Engineering
http://free-electrons.com

Re: [PATCH 0/2] Translate of PCI address without PCI enabled

[Grant Likely]

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On Wed, 19 Feb 2014 21:50:28 -0300, Ezequiel Garcia <ezequiel.garcia@free-electrons.com> wrote:
> On Wed, Feb 19, 2014 at 11:14:54PM +0100, Gregory CLEMENT wrote:
> > Hello,
> > 
> > This patch set makes the use of the of PCI address translator less
> > restrictive. At the end it will allow to use the mvebu_get_soc_id
> > unconditionally.
> > 
> > The mvebu SoC (such as Kirkwood, Dove or Armada XP for instance) come
> > with an IP of a PCI controller. The ID and the revision of a SoC are
> > stored in the registers of this controller. Being able to get this
> > information allows to deals with errata more dynamically.
> > 
> > To manage to read this information, we need to map the registers, and
> > for this we need to use the of PCI translator which depend of the PCI
> > support.
> > 
> > However there are mvebu board without any PCI devices, and where
> > selecting the PCI support would be useless.
> > 
> > Moreover translating an address from a PCI node of the device-tree
> > into a CPU physical address doesn't require the core PCI
> > support. Those translations are just related to the device tree
> > itself.
> > 
> > The 1st patch introduces a new config symbol: OF_ADDRESS_PCI, which
> > will be selected as soon as PCI will be selected, so we remains in the
> > same situation the current code. It should go to the of tree.
> > 
> > The 2nd patch selects OF_ADDRESS_PCI as soon as ARCH_MVEBU will be
> > selected. This will make mvebu_get_soc_id available even without the
> > PCI support. It should go to the mvebu tree.
> > 
> > Thanks,
> > 
> > Gregory CLEMENT (2):
> >   of: Allows to use the PCI translator without the PCI core
> >   ARM: mvebu: Allows to get the SoC ID even without PCI enabled
> > 
> >  arch/arm/mach-mvebu/Kconfig | 1 +
> >  drivers/of/Kconfig          | 4 ++++
> >  drivers/of/address.c        | 8 +++++---
> >  3 files changed, 10 insertions(+), 3 deletions(-)
> > 
> > -- 
> > 1.8.1.2
> > 
> 
> On XP GP and CONFIG_PCI=n, without the patches I get this:
> 
>   mvebu-soc-id: cannot map registers
> 
> and after applying the patches I have:
> 
>   mvebu-soc-id: MVEBU SoC ID=0x7846, Rev=0x2
> 
> Tested-by: Ezequiel Garcia <ezequiel.garcia@free-electrons.com>
> Reviewed-by: Ezequiel Garcia <ezequiel.garcia@free-electrons.com>

Applied both, thanks.

g.

> 
> Thanks for taking care of this.
> -- 
> Ezequiel García, Free Electrons
> Embedded Linux, Kernel and Android Engineering
> http://free-electrons.com