[igt-dev] [PATCH i-g-t v2 1/3] lib/igt_device: add igt_device_get_pci_addr by fd

[Chris Wilson]

Quoting Daniel Mrzyglod (2019-04-10 09:28:37)
> From: Michał Winiarski <michal.winiarski at intel.com>
> 
> This function get us in easy way pci adress.
> It allows us to make things a little bit more generic.
> Also, we now require fd rather than doing guesswork when it comes to pci address.
> 
> Signed-off-by: Michał Winiarski <michal.winiarski at intel.com>
> Cc: Chris Wilson <chris at chris-wilson.co.uk>
> Signed-off-by: Daniel Mrzyglod <daniel.t.mrzyglod at intel.com>
> ---
>  lib/igt_device.c | 122 +++++++++++++++++++++++++++++++++++++++++++++++
>  lib/igt_device.h |   2 +
>  2 files changed, 124 insertions(+)
> 
> diff --git a/lib/igt_device.c b/lib/igt_device.c
> index 08f39c8b..f3d2a9f5 100644
> --- a/lib/igt_device.c
> +++ b/lib/igt_device.c
> @@ -21,11 +21,14 @@
>   * IN THE SOFTWARE.
>   *
>   */
> +#include <sys/types.h>
> +#include <fcntl.h>
>  
>  #include <sys/stat.h>
>  #include <sys/sysmacros.h>
>  #include "igt.h"
>  #include "igt_device.h"
> +#include "igt_sysfs.h"
>  
>  int __igt_device_set_master(int fd)
>  {
> @@ -103,3 +106,122 @@ int igt_device_get_card_index(int fd)
>  
>         return minor(st.st_rdev);
>  }
> +
> +#define IGT_DEV_PATH_LEN 80
> +
> +static bool igt_device_is_pci(int fd)
> +{
> +       char path[IGT_DEV_PATH_LEN];
> +       char *subsystem;
> +       int sysfs;
> +       int len;
> +
> +       sysfs = igt_sysfs_open(fd);
> +       if (sysfs == -1)
> +               return false;
> +
> +       len = readlinkat(sysfs, "device/subsystem", path, sizeof(path) - 1);
close(sysfs);

> +       if (len == -1)
> +               return false;
> +       path[len] = '\0';
> +
> +       subsystem = strrchr(path, '/');
> +       if (!subsystem)
> +               return false;
> +
> +       return strcmp(subsystem, "/pci") == 0;
> +}
> +
> +struct igt_pci_addr {
> +       unsigned int domain;
> +       unsigned int bus;
> +       unsigned int device;
> +       unsigned int function;
> +};
> +
> +static int igt_device_get_pci_addr(int fd, struct igt_pci_addr *pci)
> +{
> +       char path[IGT_DEV_PATH_LEN];
> +       char *buf;
> +       int sysfs;
> +       int len;
> +
> +       if (!igt_device_is_pci(fd))
> +               return -ENODEV;
> +
> +       sysfs = igt_sysfs_open(fd);
> +       if (sysfs == -1)
> +               return -ENOENT;
> +
> +       len = readlinkat(sysfs, "device", path, sizeof(path) - 1);
close(sysfs);

> +       if (len == -1)
> +               return -ENOENT;
> +       path[len] = '\0';
> +
> +       buf = strrchr(path, '/');
> +       if (!buf)
> +               return -ENOENT;
> +
> +       if (sscanf(buf, "/%4x:%2x:%2x.%2x",
> +                  &pci->domain, &pci->bus,
> +                  &pci->device, &pci->function) != 4) {
> +               igt_warn("Unable to extract PCI device address from '%s'\n", buf);

buf includes '/' here, not the prettiest.

> +               return -ENOENT;
> +       }
> +
> +       return 0;
> +}