Hi Lirenzo,

On Thu, 14 Feb 2019 10:31:38 +0000,
Lorenzo Pieralisi [off-list ref] wrote:

[CC'ed MarcZ]

On Thu, Feb 14, 2019 at 10:27:19AM +0530, Kishon Vijay Abraham I wrote:

quoted

Hi Lorenzo,

On 13/02/19 10:27 PM, Lorenzo Pieralisi wrote:

quoted

On Wed, Feb 13, 2019 at 06:56:23PM +0530, Kishon Vijay Abraham I wrote:

quoted

ks_pcie_legacy_irq_handler() uses 'virq' to get the IRQ number offset.
This offset is used to get the correct IRQ_STATUS register
corresponding to the IRQ line that raised the interrupt.
There is no guarantee that 'virq' assigned for consecutive hardware
IRQ will be contiguous. And this might get us an incorrect IRQ number
offset.

Fix it here by using 'hwirq' to get the IRQ number offset.

Link: https://lkml.kernel.org/r/bb081d21-7c03-0357-4294-7e92d95d838c@arm.com
Signed-off-by: Kishon Vijay Abraham I <redacted>
---
 drivers/pci/controller/dwc/pci-keystone.c | 17 +++++++++++++----
 1 file changed, 13 insertions(+), 4 deletions(-)

diff --git a/drivers/pci/controller/dwc/pci-keystone.c b/drivers/pci/controller/dwc/pci-keystone.c
index e8b1d8eca78e..d35ac712a9f8 100644
--- a/drivers/pci/controller/dwc/pci-keystone.c
+++ b/drivers/pci/controller/dwc/pci-keystone.c

@@ -87,7 +87,7 @@ struct keystone_pcie {
 	struct dw_pcie		*pci;
 	/* PCI Device ID */
 	u32			device_id;
-	int			legacy_host_irqs[PCI_NUM_INTX];
+	int			legacy_host_irq;
 	struct			device_node *legacy_intc_np;
 
 	int			msi_host_irqs[MAX_MSI_HOST_IRQS];

@@ -582,11 +582,11 @@ static void ks_pcie_msi_irq_handler(struct irq_desc *desc)
  */
 static void ks_pcie_legacy_irq_handler(struct irq_desc *desc)
 {
-	unsigned int irq = irq_desc_get_irq(desc);
+	unsigned int irq = desc->irq_data.hwirq;
 	struct keystone_pcie *ks_pcie = irq_desc_get_handler_data(desc);
 	struct dw_pcie *pci = ks_pcie->pci;
 	struct device *dev = pci->dev;
-	u32 irq_offset = irq - ks_pcie->legacy_host_irqs[0];
+	u32 irq_offset = irq - ks_pcie->legacy_host_irq;

I think you should use the plain hwirq number (that if I understand
correctly range in [0,3]) and drop legacy_host_irq.

The hwirq is [80, 83] for Keystone. We store legacy_host_irq (for Keystone it
is 80) to get the correct offset in the range [0, 3].

IIUC the _parent_ hw_irq number should be what you need here, Marc (if
he has time) can correct me if I am wrong (or what I am suggesting is
a violation of IRQ domain bstraction usage).

It isn't pretty, but it is something we already do in some cases (see
irq-gic-v3-mbi.c::mbi_compose_msi_msg as an infamous example).

Thanks,

	M.

-- 
Jazz is not dead, it just smell funny.

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