PCI: rockchip-ep: Fix MSI IRQ data mapping

The call to rockchip_pcie_prog_ep_ob_atu() used to map the PCI address
of MSI data to the memory window allocated on probe for IRQs is done
in rockchip_pcie_ep_send_msi_irq() assuming a fixed alignment to a
256B boundary of the PCI address.  This is not correct as the alignment
constraint for the RK3399 PCI mapping depends on the number of bits of
address changing in the mapped region. This leads to an unstable system
which sometimes work and sometimes does not (crashing on paging faults
when memcpy_toio() or memcpy_fromio() are used).

Similar to regular data mapping, the MSI data mapping must thus be
handled according to the information provided by
rockchip_pcie_ep_align_addr(). Modify rockchip_pcie_ep_send_msi_irq()
to use rockchip_pcie_ep_align_addr() to correctly program entry 0 of
the ATU for sending MSI IRQs.

Link: https://lore.kernel.org/r/20241017015849.190271-7-dlemoal@kernel.org
Signed-off-by: Damien Le Moal <dlemoal@kernel.org>
Signed-off-by: Krzysztof Wilczyński <kwilczynski@kernel.org>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>

Author: damien-lemoal

drivers/pci/controller/pcie-rockchip-ep.c

@@ -382,9 +382,10 @@ static int rockchip_pcie_ep_send_msi_irq(struct rockchip_pcie_ep *ep, u8 fn,
 {
 	struct rockchip_pcie *rockchip = &ep->rockchip;
 	u32 flags, mme, data, data_mask;
+	size_t irq_pci_size, offset;
+	u64 irq_pci_addr;
 	u8 msi_count;
 	u64 pci_addr;
-	u32 r;
 
 	/* Check MSI enable bit */
 	flags = rockchip_pcie_read(&ep->rockchip,
@@ -420,18 +421,21 @@ static int rockchip_pcie_ep_send_msi_irq(struct rockchip_pcie_ep *ep, u8 fn,
 				       PCI_MSI_ADDRESS_LO);
 
 	/* Set the outbound region if needed. */
-	if (unlikely(ep->irq_pci_addr != (pci_addr & PCIE_ADDR_MASK) ||
+	irq_pci_size = ~PCIE_ADDR_MASK + 1;
+	irq_pci_addr = rockchip_pcie_ep_align_addr(ep->epc,
+						   pci_addr & PCIE_ADDR_MASK,
+						   &irq_pci_size, &offset);
+	if (unlikely(ep->irq_pci_addr != irq_pci_addr ||
 		     ep->irq_pci_fn != fn)) {
-		r = rockchip_ob_region(ep->irq_phys_addr);
-		rockchip_pcie_prog_ep_ob_atu(rockchip, fn, r,
-					     ep->irq_phys_addr,
-					     pci_addr & PCIE_ADDR_MASK,
-					     ~PCIE_ADDR_MASK + 1);
-		ep->irq_pci_addr = (pci_addr & PCIE_ADDR_MASK);
+		rockchip_pcie_prog_ep_ob_atu(rockchip, fn,
+					rockchip_ob_region(ep->irq_phys_addr),
+					ep->irq_phys_addr,
+					irq_pci_addr, irq_pci_size);
+		ep->irq_pci_addr = irq_pci_addr;
 		ep->irq_pci_fn = fn;
 	}
 
-	writew(data, ep->irq_cpu_addr + (pci_addr & ~PCIE_ADDR_MASK));
+	writew(data, ep->irq_cpu_addr + offset + (pci_addr & ~PCIE_ADDR_MASK));
 	return 0;
 }