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Date: Thu, 13 Dec 2007 10:45:02 +1100 From: Aras Vaichas <arasv@...tech.com.au> To: linux-kernel@...r.kernel.org Subject: mmaping an IO port device Hi, Can I implement mmap with an io port connected device on an x86 based CPU? Background: I've got a device driver which can be compiled for either x86 or ARM. The driver provides an interface to an FPGA via either an IO port (0x180) on the x86 or as a memory mapped SRAM-like device (0x30000000) on the ARM. To get myself an "address" for ioread calls I use: FPGA_base = (u32) ioremap_nocache(FPGA_REG_IO_BASE, SZ_4K) for both CPU types. FPGA_REG_IO_BASE is set to either 0x180 or 0x30000000 for x86 and ARM respectively. I then call ioread16(FPGA_base + FPGA_register) for both x86 and ARM and it all works perfectly. No problems there. My problem is that I am now moving from ioctl calls to a mmap interface. This isn't a problem with ARM as I can pass (0x30000000 >> PAGE_SHIFT) to remap_pfn_range() in the .mmap fops function but I can't pass 0x180 because ... well, it's obvious. Is there a trick? Aras ______________________________________________________________________ This email has been scanned by the MessageLabs Email Security System. For more information please visit http://www.messagelabs.com/email ______________________________________________________________________ -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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