mach/io.h cleanup and removal question

Andrew Lunn andrew at
Fri Jun 8 06:20:40 EDT 2012

Hi Rob

Your patchset for mach/io.h cleanup and remove, causes problems on

mach/io.h for orion5x had a:

#define IO_SPACE_LIMIT		0xffffffff

which got removed. This results in a panic at boot:

         * IORESOURCE_IO
        sys->io_offset = 0;
        res[0].name = "PCIe I/O Space";
        res[0].flags = IORESOURCE_IO;
        res[0].start = ORION5X_PCIE_IO_BUS_BASE;
        res[0].end = res[0].start + ORION5X_PCIE_IO_SIZE - 1;
        if (request_resource(&ioport_resource, &res[0]))
                panic("Request PCIe IO resource failed\n");

ORION5X_PCIE_IO_SIZE is 1MB, so the allocation fails because of the
64K default.

arch/arm/include/asm/io.h has the comment:

 * This is the limit of PC card/PCI/ISA IO space, which is by default
 * 64K if we have PC card, PCI or ISA support.  Otherwise, default to
 * zero to prevent ISA/PCI drivers claiming IO space (and potentially
 * oopsing.)
 * Only set this larger if you really need inb() to operate over
 * a larger address space.  Note that SOC_COMMON ioremaps each sockets
 * IO space area, and so inb() must be defined to operate as per
 * readb() on such platforms.

Now, i know nothing about how PCI works... So i have a question:

Which is better, put back parts of io.h so allowing the 1MB
request_resource, or reduce ORION5X_PCIE_IO_SIZE to 64KB, since from
the comment it is unlikely an PCI card needs more than 64KB?


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