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<html xmlns="http://www.w3.org/1999/xhtml"><head><meta http-equiv="Content-Type" content="text/html; charset=ANSI_X3.4-1968" /><title>Example code using uio_pci_generic</title><meta name="generator" content="DocBook XSL Stylesheets V1.75.2" /><link rel="home" href="index.html" title="The Userspace I/O HOWTO" /><link rel="up" href="uio_pci_generic.html" title="Chapter 5. Generic PCI UIO driver" /><link rel="prev" href="ch05s03.html" title="Writing userspace driver using uio_pci_generic" /><link rel="next" href="apa.html" title="Appendix A. Further information" /></head><body><div class="navheader"><table width="100%" summary="Navigation header"><tr><th colspan="3" align="center">Example code using uio_pci_generic</th></tr><tr><td width="20%" align="left"><a accesskey="p" href="ch05s03.html">Prev</a> </td><th width="60%" align="center">Chapter 5. Generic PCI UIO driver</th><td width="20%" align="right"> <a accesskey="n" href="apa.html">Next</a></td></tr></table><hr /></div><div class="sect1" title="Example code using uio_pci_generic"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a id="uio_pci_generic_example"></a>Example code using uio_pci_generic</h2></div></div></div><p>
Here is some sample userspace driver code using uio_pci_generic:
</p><pre class="programlisting">
#include <stdlib.h>
#include <stdio.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <errno.h>
int main()
{
int uiofd;
int configfd;
int err;
int i;
unsigned icount;
unsigned char command_high;
uiofd = open("/dev/uio0", O_RDONLY);
if (uiofd < 0) {
perror("uio open:");
return errno;
}
configfd = open("/sys/class/uio/uio0/device/config", O_RDWR);
if (uiofd < 0) {
perror("config open:");
return errno;
}
/* Read and cache command value */
err = pread(configfd, &command_high, 1, 5);
if (err != 1) {
perror("command config read:");
return errno;
}
command_high &= ~0x4;
for(i = 0;; ++i) {
/* Print out a message, for debugging. */
if (i == 0)
fprintf(stderr, "Started uio test driver.\n");
else
fprintf(stderr, "Interrupts: %d\n", icount);
/****************************************/
/* Here we got an interrupt from the
device. Do something to it. */
/****************************************/
/* Re-enable interrupts. */
err = pwrite(configfd, &command_high, 1, 5);
if (err != 1) {
perror("config write:");
break;
}
/* Wait for next interrupt. */
err = read(uiofd, &icount, 4);
if (err != 4) {
perror("uio read:");
break;
}
}
return errno;
}
</pre><p>
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