[Added driver author to Cc:]
On Wed, Aug 29, 2012 at 11:19:00PM +0000, Worth, Kevin wrote:
> I have below what appears to be a mostly-functional device using the UIO
> Platform Driver. The /sys entries I'd expect appear, /proc/iomem contains "
> d0000000-d0000fff : myfpga", and lsuio sees the properties that I've set.
> However an mmap() from userspace (either my test program below or lsuio)
> fails. So close! (at least it would seem)
>
> Finding a good example for this did not come easily (which is why I'm hitting
> LKML, since I know it'll get a lot of eyeballs and be archived). Maybe there
> was something obvious I missed, but the only "official" documentation I could
> locate was http://www.kernel.org/doc/htmldocs/uio-howto.html#using_uio_pdrv ,
> and most everything else was snippets from presentations, papers, and forums
> that lacked completeness.
>
> Thanks for the help any might be able to offer.
> Please CC me on replies as I'm not ready to drink from the fire hose that is
> an LKML subscription.
>
> # lsuio -v -m
> uio0: name=uio_myfpga, version=0.1, events=0
> map[0]: addr=0xD0000000, size=4096, mmap test: FAILED
> Device attributes:
> uevent=DRIVER=uio_pdrv
> modalias=platform:uio_pdrv
>
> ------Kernelspace portion-------
>
> #include <linux/platform_device.h>
> #include <linux/uio_driver.h>
> #include <linux/module.h>
>
> #define MYFPGA_BASE 0xd0000000 // 3G
> #define MYFPGA_SIZE 0x00040000 // 256k
>
> static struct resource myfpga_resources[] = {
> {
> .start = MYFPGA_BASE,
> .end = MYFPGA_BASE + MYFPGA_SIZE - 1,
> .name = "myfpga",
> .flags = IORESOURCE_MEM
> }
> };
>
> static struct uio_info myfpga_uio_info = {
> .name = "uio_myfpga",
> .version = "0.1",
> .irq = UIO_IRQ_CUSTOM,
> .mem = {
> {
> .name = "myfpga",
> .memtype = UIO_MEM_PHYS,
> .addr = MYFPGA_BASE,
> .size = MYFPGA_SIZE
> }
> }
> };
>
> static struct platform_device_info myfpga_uio_pdevinfo = {
> .name = "uio_pdrv",
> .id = -1,
> .res = myfpga_resources,
> .num_res = 1,
> .data = &myfpga_uio_info,
> .size_data = sizeof(struct uio_info)
> };
>
> static struct platform_device *myfpga_uio_pdev;
>
> static int __init myfpga_init(void)
> {
> myfpga_uio_pdev = platform_device_register_full(&myfpga_uio_pdevinfo);
> if (IS_ERR(myfpga_uio_pdev)) {
> return PTR_ERR(myfpga_uio_pdev);
> }
>
> return 0;
> }
>
> static void __exit myfpga_exit(void)
> {
> platform_device_unregister(myfpga_uio_pdev);
> }
>
> module_init(myfpga_init);
> module_exit(myfpga_exit);
>
> ------Userspace portion-------
>
> #include <sys/types.h>
> #include <sys/mman.h>
> #include <sys/stat.h>
>
> #include <dirent.h>
> #include <string.h>
> #include <stdlib.h>
> #include <stdio.h>
> #include <fcntl.h>
> #include <unistd.h>
>
> #define MYFPGA_BASE 0xd0000000 // 3G
> #define MYFPGA_SIZE 0x00040000 // 256k
> #define MYFPGA_UIO_NUM 0 // uio0
That's misleading regarding its use below. The factor you need for mmap
is the number of the mapping, not uio0, uio1...
>
> int main (int argc, char *argv[])
> {
> int fd;
> void *iomem;
> fd = open("/dev/uio0", O_RDWR|O_SYNC);
Does it work with O_RDWR ?
Thanks,
Hans
> if (fd < 0) {
> printf("failed to open /dev/uio0, quitting\n");
> return -1;
> }
> /* Note offset has a special meaning with uio devices */
> iomem = mmap(NULL, MYFPGA_SIZE, PROT_READ | PROT_WRITE, MAP_SHARED, fd,
> MYFPGA_UIO_NUM * getpagesize());
> if (iomem == MAP_FAILED) {
> printf("mmap failed, quitting\n");
> close(fd);
> return -2;
> }
> printf("mmap successful!\n");
> munmap(iomem, MYFPGA_SIZE);
> close(fd);
> return 0;
> }
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