On 2015-02-07 11:56, Paul Bolle wrote:

On Fri, 2015-02-06 at 20:51 +0100, Stefan Agner wrote:

quoted

This adds support for Vybrid's interrupt router. On VF6xx models,
almost all peripherals can be used by either of the two CPU's,
the Cortex-A5 or the Cortex-M4. The interrupt router routes the
peripheral interrupts to the configured CPU.

This IRQ chip driver configures the interrupt router to route
the requested interrupt to the CPU the kernel is running on.
The driver makes use of the irqdomain hierarchy support. The
parent is given by the device tree. This should be one of the
two possible parents either ARM GIC or the ARM NVIC interrupt
controller. The latter is currently not yet supported.

Note that there is no resource control mechnism implemented to
avoid concurrent access of the same peripheral. The user needs
to make sure to use device trees which assign the peripherals
orthogonally. However, this driver warns the user in case the
interrupt is already configured for the other CPU. This provides
a poor man's resource controller.

Acked-by: Marc Zyngier <redacted>
Signed-off-by: Stefan Agner <stefan@agner.ch>
---
 arch/arm/mach-imx/Kconfig           |   1 +
 drivers/irqchip/Kconfig             |  11 ++
 drivers/irqchip/Makefile            |   1 +
 drivers/irqchip/irq-vf610-mscm-ir.c | 206 ++++++++++++++++++++++++++++++++++++
 4 files changed, 219 insertions(+)
 create mode 100644 drivers/irqchip/irq-vf610-mscm-ir.c

diff --git a/arch/arm/mach-imx/Kconfig b/arch/arm/mach-imx/Kconfig
index e8627e0..bf91a59 100644
--- a/arch/arm/mach-imx/Kconfig
+++ b/arch/arm/mach-imx/Kconfig

@@ -631,6 +631,7 @@ config SOC_IMX6SX

 config SOC_VF610
 	bool "Vybrid Family VF610 support"
+	select VF610_MSCM_IR
 	select ARM_GIC
 	select PINCTRL_VF610
 	select PL310_ERRATA_769419 if CACHE_L2X0

diff --git a/drivers/irqchip/Kconfig b/drivers/irqchip/Kconfig
index cc79d2a..9c13d81 100644
--- a/drivers/irqchip/Kconfig
+++ b/drivers/irqchip/Kconfig

@@ -136,6 +136,17 @@ config IRQ_CROSSBAR
 	  a free irq and configures the IP. Thus the peripheral interrupts are
 	  routed to one of the free irqchip interrupt lines.

+config VF610_MSCM_IR
+	bool
+	help
+	  Support for MSCM interrupt router available on Vybrid SoC's. The
+	  interrupt router is between the CPU's interrupt controller and the
+	  peripheral. The router allows to route the peripheral interrupts to
+	  one of the two available CPU's on Vybrid VF6xx SoC's (Cortex-A5 or
+	  Cortex-M4). The router will be configured transparently on a IRQ
+	  request.
+	select IRQ_DOMAIN_HIERARCHY
+

As far as I can tell this new Kconfig symbol operates in lockstep with
SOC_VF610: if SOC_VF610 is set, this will also be set, and if SOC_VF610
is not set, this won't be set either. Is a separate symbol needed?

Theoretically, this could be used by other SoC's. However, afaik the
i.MX6 SoloX, which one could see as something like the successor of
Vybrid, implements the interrupt routing differently. So I would be fine
to just use the SOC_VF610 symbol instead.

The only thing which I would rather prefer to keep is the comment what
this is all about (the help text). But I guess I could move that as
comment into the source file...

If you decide to keep it, I have two minor nits.

1) Make the help text the last option of the Kconfig entry. It's legal
to put Kconfig options in any order that you'd like. But with very few
exceptions, the help text is always the last. Please use that pattern.

2) This Kconfig entry has no prompt, so I'm not aware of a way that
people ever can read this help text when running "make *configure". So
this help text is basically a comment. You might as well format it as a
comment then.

quoted

 config KEYSTONE_IRQ
 	tristate "Keystone 2 IRQ controller IP"
 	depends on ARCH_KEYSTONE

--
Stefan