mips: drop GENERIC_IOMAP wrapper

All PIO on MIPS platforms is memory mapped, so there is no benefit in
the lib/iomap.c wrappers that switch between inb/outb and readb/writeb
style accessses.

In fact, the '#define PIO_RESERVED 0' setting completely disables
the GENERIC_IOMAP functionality, and the '#define PIO_OFFSET
mips_io_port_base' setting is based on a misunderstanding of what the
offset is meant to do.

MIPS started using GENERIC_IOMAP in 2018 with commit b962aeb02205 ("MIPS:
Use GENERIC_IOMAP") replacing a simple custom implementation of the same
interfaces, but at the time the asm-generic/io.h version was not usable
yet. Since the header is now always included, it's now possible to go
back to the even simpler version.

Use the normal GENERIC_PCI_IOMAP functionality for all mips platforms
without the hacky GENERIC_IOMAP, and provide a custom pci_iounmap()
for the CONFIG_PCI_DRIVERS_LEGACY case to ensure the I/O port base never
gets unmapped.

The readsl() prototype needs an extra 'const' keyword to make it
compatible with the generic ioread32_rep() alias.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>

1 files changed, 9 insertions, 0 deletions

diff --git a/arch/mips/lib/iomap-pci.c b/arch/mips/lib/iomap-pci.c
index a9cb28813f0b..2f82c776c6d0 100644
--- a/arch/mips/lib/iomap-pci.c
+++ b/arch/mips/lib/iomap-pci.c
@@ -43,4 +43,13 @@ void __iomem *__pci_ioport_map(struct pci_dev *dev,
 	return (void __iomem *) (ctrl->io_map_base + port);
 }
 
+void pci_iounmap(struct pci_dev *dev, void __iomem *addr)
+{
+	struct pci_controller *ctrl = dev->bus->sysdata;
+	void __iomem *base = (void __iomem *)ctrl->io_map_base;
+
+	if (addr < base || addr > (base + resource_size(ctrl->io_resource)))
+		iounmap(addr);
+}
+
 #endif /* CONFIG_PCI_DRIVERS_LEGACY */