Re: [PATCH] irqchip: mvebu-odmi: select GENERIC_MSI_IRQ_DOMAIN

From: Thomas Petazzoni
Date: Tue Feb 21 2017 - 11:59:56 EST


On Tue, 14 Feb 2017 22:24:36 +0100, Arnd Bergmann wrote:
> This driver uses the MSI domain but has no strict dependency on PCI_MSI, so we
> may run into a build failure when CONFIG_GENERIC_MSI_IRQ_DOMAIN is disabled:
> drivers/irqchip/irq-mvebu-odmi.c:152:15: error: variable 'odmi_msi_ops' has initializer but incomplete type
> static struct msi_domain_ops odmi_msi_ops = {
> ^~~~~~~~~~~~~~
> drivers/irqchip/irq-mvebu-odmi.c:155:15: error: variable 'odmi_msi_domain_info' has initializer but incomplete type
> static struct msi_domain_info odmi_msi_domain_info = {
> ^~~~~~~~~~~~~~~
> drivers/irqchip/irq-mvebu-odmi.c:156:3: error: 'struct msi_domain_info' has no member named 'flags'
> ^~~~~
> drivers/irqchip/irq-mvebu-odmi.c:156:12: error: 'MSI_FLAG_USE_DEF_DOM_OPS' undeclared here (not in a function)
> ^~~~~~~~~~~~~~~~~~~~~~~~
> drivers/irqchip/irq-mvebu-odmi.c:156:39: error: 'MSI_FLAG_USE_DEF_CHIP_OPS' undeclared here (not in a function); did you mean 'MSI_FLAG_USE_DEF_DOM_OPS'?
> Selecting the option from this driver seems to solve this nicely, though I could
> not find any other instance of this in irqchip drivers.

Here is my explanation of why MVEBU_ODMI is the only one affected:
because it's the only one that provides only platform MSI and not PCI

Let's look at the other irqchip drivers using msi_domain_ops:

irq-gic-v2m.c:static struct msi_domain_ops gicv2m_pmsi_ops = {
irq-gic-v3-its-pci-msi.c:static struct msi_domain_ops its_pci_msi_ops = {
irq-gic-v3-its-platform-msi.c:static struct msi_domain_ops its_pmsi_ops = {
irq-gic-v3-its.c:static struct msi_domain_ops its_msi_domain_ops = {
irq-mvebu-odmi.c:static struct msi_domain_ops odmi_msi_ops = {

So, besides mvebu-odmi, we've got GICv2m and GIv3 ITS. Their Kconfig
declaration is:

config ARM_GIC_V2M
depends on PCI
select ARM_GIC
select PCI_MSI

config ARM_GIC_V3_ITS
depends on PCI
depends on PCI_MSI
select ACPI_IORT if ACPI

so both of them "select PCI_MSI". Then we have:

def_bool ARC || ARM || ARM64 || X86
depends on PCI_MSI

So, when we are on ARC, ARM, ARM64 or x86, and PCI_MSI is enabled,
GENERIC_MSI_IRQ_DOMAIN is automatically enabled. So basically the fact
that GICv2m and GICv3 "select PCI_MSI" ensure that
"GENERIC_MSI_IRQ_DOMAIN" will be enabled.


> Signed-off-by: Arnd Bergmann <arnd@xxxxxxxx>

Acked-by: Thomas Petazzoni <thomas.petazzoni@xxxxxxxxxxxxxxxxxx>


Thomas Petazzoni, CTO, Free Electrons
Embedded Linux and Kernel engineering