Re: [PATCH v2 05/15] PCI: xilinx: Convert to MSI domains

[Marc Zyngier]

On Wed, 24 Mar 2021 12:42:24 +0000,
Bharat Kumar Gogada <bharatku@xxxxxxxxxx> wrote:
> 
> Hi Marc,
> 
> Thanks for the patch. 
> 
> > Subject: [PATCH v2 05/15] PCI: xilinx: Convert to MSI domains
> > 
> > In anticipation of the removal of the msi_controller structure, convert the
> > ancient xilinx host controller driver to MSI domains.
> > 
> > We end-up with the usual two domain structure, the top one being a generic
> > PCI/MSI domain, the bottom one being xilinx-specific and handling the
> > actual HW interrupt allocation.
> > 
> > This allows us to fix some of the most appalling MSI programming, where the
> > message programmed in the device is the virtual IRQ number instead of the
> > allocated vector number. The allocator is also made safe with a mutex. This
> > should allow support for MultiMSI, but I decided not to even try, since I
> > cannot test it.
> > 
> > Acked-by: Bjorn Helgaas <bhelgaas@xxxxxxxxxx>
> > Signed-off-by: Marc Zyngier <maz@xxxxxxxxxx>
> > ---
> >  drivers/pci/controller/Kconfig       |   2 +-
> >  drivers/pci/controller/pcie-xilinx.c | 234 +++++++++++----------------
> >  2 files changed, 97 insertions(+), 139 deletions(-)
> > 
> > diff --git a/drivers/pci/controller/Kconfig b/drivers/pci/controller/Kconfig
> > index 5cc07d28a3a0..60045f7aafc5 100644
> ...
> 
> 
> > +static struct irq_chip xilinx_msi_bottom_chip = {
> > +	.name			= "Xilinx MSI",
> > +	.irq_set_affinity 	= xilinx_msi_set_affinity,
> > +	.irq_compose_msi_msg	= xilinx_compose_msi_msg,
> > +};
> > 
> I see a crash while testing MSI in handle_edge_irq
> [<c015bdd4>] (handle_edge_irq) from [<c0157164>] (generic_handle_irq+0x28/0x38)
> [<c0157164>] (generic_handle_irq) from [<c03a9714>] (xilinx_pcie_intr_handler+0x17c/0x2b0)
> [<c03a9714>] (xilinx_pcie_intr_handler) from [<c0157d94>] (__handle_irq_event_percpu+0x3c/0xc0)
> [<c0157d94>] (__handle_irq_event_percpu) from [<c0157e44>] (handle_irq_event_percpu+0x2c/0x7c)
> [<c0157e44>] (handle_irq_event_percpu) from [<c0157ecc>] (handle_irq_event+0x38/0x5c)
> [<c0157ecc>] (handle_irq_event) from [<c015bc8c>] (handle_fasteoi_irq+0x9c/0x114)

Thanks for that. Can you please try the following patch and let me
know if it helps?

Thanks,

	M.

diff --git a/drivers/pci/controller/pcie-xilinx.c b/drivers/pci/controller/pcie-xilinx.c
index ad9abf405167..14001febf59a 100644
--- a/drivers/pci/controller/pcie-xilinx.c
+++ b/drivers/pci/controller/pcie-xilinx.c
@@ -194,8 +194,18 @@ static struct pci_ops xilinx_pcie_ops = {
 
 /* MSI functions */
 
+static void xilinx_msi_top_irq_ack(struct irq_data *d)
+{
+	/*
+	 * xilinx_pcie_intr_handler() will have performed the Ack.
+	 * Eventually, this should be fixed and the Ack be moved in
+	 * the respective callbacks for INTx and MSI.
+	 */
+}
+
 static struct irq_chip xilinx_msi_top_chip = {
 	.name		= "PCIe MSI",
+	.irq_ack	= xilinx_msi_top_irq_ack,
 };
 
 static int xilinx_msi_set_affinity(struct irq_data *d, const struct cpumask *mask, bool force)
@@ -206,7 +216,7 @@ static int xilinx_msi_set_affinity(struct irq_data *d, const struct cpumask *mas
 static void xilinx_compose_msi_msg(struct irq_data *data, struct msi_msg *msg)
 {
 	struct xilinx_pcie_port *pcie = irq_data_get_irq_chip_data(data);
-	phys_addr_t pa = virt_to_phys(pcie);
+	phys_addr_t pa = ALIGN_DOWN(virt_to_phys(pcie), SZ_4K);
 
 	msg->address_lo = lower_32_bits(pa);
 	msg->address_hi = upper_32_bits(pa);
@@ -468,7 +478,7 @@ static int xilinx_pcie_init_irq_domain(struct xilinx_pcie_port *port)
 
 	/* Setup MSI */
 	if (IS_ENABLED(CONFIG_PCI_MSI)) {
-		phys_addr_t pa = virt_to_phys(port);
+		phys_addr_t pa = ALIGN_DOWN(virt_to_phys(port), SZ_4K);
 
 		ret = xilinx_allocate_msi_domains(port);
 		if (ret)

-- 
Without deviation from the norm, progress is not possible.