PCI: pci-bridge-emul: Add support for new flag PCI_BRIDGE_EMUL_NO_IO_FORWARD

Like PCI_BRIDGE_EMUL_NO_PREFMEM_FORWARD, this new flag specifies that
emulated PCI bridge does not support forwarding of IO requests in given
range between primary and secondary buses. This flag should be used as
argument for pci_bridge_emul_init() for hardware setup without IO support.

Setting this flag cause that IO base and limit registers are read-only.

Link: https://lore.kernel.org/r/20220104153529.31647-5-pali@kernel.org
Signed-off-by: Pali Rohár <pali@kernel.org>
Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Reviewed-by: Rob Herring <robh@kernel.org>

diff --git a/drivers/pci/pci-bridge-emul.c b/drivers/pci/pci-bridge-emul.c
index ceacba03e7144f9315656e6ff91c9b7abe5f1175..a16f9e30099ef136ea60333b78ec258e23a3dbb2 100644 (file)
--- a/drivers/pci/pci-bridge-emul.c
+++ b/drivers/pci/pci-bridge-emul.c
@@ -382,6 +382,15 @@ int pci_bridge_emul_init(struct pci_bridge_emul *bridge,
                bridge->pci_regs_behavior[PCI_PREF_MEMORY_BASE / 4].rw = 0;
        }
 
+       if (flags & PCI_BRIDGE_EMUL_NO_IO_FORWARD) {
+               bridge->pci_regs_behavior[PCI_COMMAND / 4].ro |= PCI_COMMAND_IO;
+               bridge->pci_regs_behavior[PCI_COMMAND / 4].rw &= ~PCI_COMMAND_IO;
+               bridge->pci_regs_behavior[PCI_IO_BASE / 4].ro |= GENMASK(15, 0);
+               bridge->pci_regs_behavior[PCI_IO_BASE / 4].rw &= ~GENMASK(15, 0);
+               bridge->pci_regs_behavior[PCI_IO_BASE_UPPER16 / 4].ro = ~0;
+               bridge->pci_regs_behavior[PCI_IO_BASE_UPPER16 / 4].rw = 0;
+       }
+
        return 0;
 }
 EXPORT_SYMBOL_GPL(pci_bridge_emul_init);

diff --git a/drivers/pci/pci-bridge-emul.h b/drivers/pci/pci-bridge-emul.h
index 087b5fa01bcf0eb7acf48c65b0b962ed450cb5cd..4953274cac18b8aa598dfc512be16c1f78c9a9ba 100644 (file)
--- a/drivers/pci/pci-bridge-emul.h
+++ b/drivers/pci/pci-bridge-emul.h
@@ -125,6 +125,12 @@ enum {
         * requests between primary and secondary buses.
         */
        PCI_BRIDGE_EMUL_NO_PREFMEM_FORWARD = BIT(0),
+
+       /*
+        * PCI bridge does not support forwarding of IO requests between
+        * primary and secondary buses.
+        */
+       PCI_BRIDGE_EMUL_NO_IO_FORWARD = BIT(1),
 };
 
 int pci_bridge_emul_init(struct pci_bridge_emul *bridge,