On Thu, Aug 31, 2017 at 11:58:17AM -0500, Bjorn Helgaas wrote:

[+cc Kishon, Thomas, Niklas, Jesper, Zhou, Gabriele, Xiaowei, Binghui,
Stanimir, Pratyush, Kukjin, Krzysztof, Richard, Murali, Minghuan, Mingkai,
Roy]

Sorry about the unwieldy cc list.  It seems like this affects every
DesignWare-based driver.

On Mon, Aug 28, 2017 at 04:23:05PM +0200, Lucas Stach wrote:

quoted

The MSI part of the controller isn't essential, so the host controller can
be registered without the MSI controller being present. This allows the
host to work in PCIe legancy interrupt only mode, if the IRQ line for the

s/legancy/legacy/

quoted

MSI controller is missing.

Signed-off-by: Lucas Stach <l.stach@pengutronix.de>
---
 drivers/pci/dwc/pcie-designware-host.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/pci/dwc/pcie-designware-host.c b/drivers/pci/dwc/pcie-designware-host.c
index d29c020da082..8494089f088d 100644
--- a/drivers/pci/dwc/pcie-designware-host.c
+++ b/drivers/pci/dwc/pcie-designware-host.c

@@ -381,7 +381,7 @@ int dw_pcie_host_init(struct pcie_port *pp)
 	if (ret)
 		pci->num_viewport = 2;
 
-	if (IS_ENABLED(CONFIG_PCI_MSI)) {
+	if (IS_ENABLED(CONFIG_PCI_MSI) && pp->msi_irq > 0) {
 		if (!pp->ops->msi_host_init) {
 			pp->irq_domain = irq_domain_add_linear(dev->of_node,
 						MAX_MSI_IRQS, &msi_domain_ops,

@@ -412,7 +412,7 @@ int dw_pcie_host_init(struct pcie_port *pp)
 	bridge->ops = &dw_pcie_ops;
 	bridge->map_irq = of_irq_parse_and_map_pci;
 	bridge->swizzle_irq = pci_common_swizzle;
-	if (IS_ENABLED(CONFIG_PCI_MSI)) {
+	if (IS_ENABLED(CONFIG_PCI_MSI) && pp->msi_irq > 0) {
 		bridge->msi = &dw_pcie_msi_chip;
 		dw_pcie_msi_chip.dev = dev;
 	}

Here are the callers of dw_pcie_host_init():

  armada8k_add_pcie_port
  artpec6_add_pcie_port       # sets pp->msi_irq
  dra7xx_add_pcie_port
  dw_plat_add_pcie_port       # sets pp->msi_irq
  exynos_add_pcie_port        # sets pp->msi_irq
  hisi_add_pcie_port
  imx6_add_pcie_port          # sets pp->msi_irq
  kirin_add_pcie_port
  ks_dw_pcie_host_init        # sets pp->ops->msi_host_init
  ls_add_pcie_port            # sets pp->ops->msi_host_init
  qcom_pcie_probe             # sets pp->msi_irq
  spear13xx_add_pcie_port

For the drivers that set pp->msi_irq (artpec6, dw_plat, exynos, imx6,
qcom), it seems like you'd want a similar follow-up change for all of
them to make the MSI IRQ optional, but you only changed imx6.  What
about the others?

For the drivers that don't set pp->msi_irq and don't set
pp->ops->msi_host_init (armada8k, dra7xx, hisi, kirin, spear13xx),
this patch means they no longer set up pp->irq_domain.  Do you intend
that?

Ping, I'm looking for a v2 that addresses this.  No hurry, just
making sure you're not waiting on me.

Bjorn