gallium: Add pipe loader for device enumeration and driver multiplexing.

The goal is to have a uniform interface to create winsys and
pipe_screen instances for any driver, exposing the device enumeration
capabilities that might be supported by the operating system (for now
there's a "drm" back-end using udev and a "sw" back-end that always
returns the same built-in devices).

The typical use case of this library will be:
>
> struct pipe_loader_device devs[n];
> struct pipe_screen *screen;
>
> pipe_loader_probe(&devs, n);
>[pick some device from the array...]
>
> screen = pipe_loader_create_screen(dev, library_search_path);
>[do something with screen...]
>
> screen->destroy(screen);
> pipe_loader_release(&devs, N);
>

A part of the code was taken from targets/gbm/pipe_loader.c, which
will be removed and replaced with calls into this library by a future
commit.

1 files changed, 144 insertions, 0 deletions

diff --git a/src/gallium/auxiliary/pipe-loader/pipe_loader.h b/src/gallium/auxiliary/pipe-loader/pipe_loader.h
new file mode 100644
index 00000000000..e41969458dd
--- /dev/null
+++ b/src/gallium/auxiliary/pipe-loader/pipe_loader.h
@@ -0,0 +1,144 @@
+/**************************************************************************
+ *
+ * Copyright 2012 Francisco Jerez
+ * All Rights Reserved.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the
+ * "Software"), to deal in the Software without restriction, including
+ * without limitation the rights to use, copy, modify, merge, publish,
+ * distribute, sub license, and/or sell copies of the Software, and to
+ * permit persons to whom the Software is furnished to do so, subject to
+ * the following conditions:
+ *
+ * The above copyright notice and this permission notice (including the
+ * next paragraph) shall be included in all copies or substantial portions
+ * of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
+ * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+ * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT.
+ * IN NO EVENT SHALL TUNGSTEN GRAPHICS AND/OR ITS SUPPLIERS BE LIABLE FOR
+ * ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
+ * TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
+ * SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ *
+ **************************************************************************/
+
+/**
+ * \file Library that provides device enumeration and creation of
+ * winsys/pipe_screen instances.
+ */
+
+#ifndef PIPE_LOADER_H
+#define PIPE_LOADER_H
+
+#include "pipe/p_compiler.h"
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+struct pipe_screen;
+
+enum pipe_loader_device_type {
+   PIPE_LOADER_DEVICE_SOFTWARE,
+   PIPE_LOADER_DEVICE_PCI,
+   NUM_PIPE_LOADER_DEVICE_TYPES
+};
+
+/**
+ * A device known to the pipe loader.
+ */
+struct pipe_loader_device {
+   enum pipe_loader_device_type type;
+
+   union {
+      struct {
+         int vendor_id;
+         int chip_id;
+      } pci;
+   }; /**< Discriminated by \a type */
+
+   const char *driver_name;
+   const struct pipe_loader_ops *ops;
+};
+
+/**
+ * Get a list of known devices.
+ *
+ * \param devs Array that will be filled with pointers to the devices
+ *             available in the system.
+ * \param ndev Maximum number of devices to return.
+ * \return Number of devices available in the system.
+ */
+int
+pipe_loader_probe(struct pipe_loader_device **devs, int ndev);
+
+/**
+ * Create a pipe_screen for the specified device.
+ *
+ * \param dev Device the screen will be created for.
+ * \param library_paths Colon-separated list of filesystem paths that
+ *                      will be used to look for the pipe driver
+ *                      module that handles this device.
+ */
+struct pipe_screen *
+pipe_loader_create_screen(struct pipe_loader_device *dev,
+                          const char *library_paths);
+
+/**
+ * Release resources allocated for a list of devices.
+ *
+ * Should be called when the specified devices are no longer in use to
+ * release any resources allocated by pipe_loader_probe.
+ *
+ * \param devs Devices to release.
+ * \param ndev Number of devices to release.
+ */
+void
+pipe_loader_release(struct pipe_loader_device **devs, int ndev);
+
+#ifdef HAVE_PIPE_LOADER_SW
+
+/**
+ * Get a list of known software devices.
+ *
+ * This function is platform-specific.
+ *
+ * \sa pipe_loader_probe
+ */
+int
+pipe_loader_sw_probe(struct pipe_loader_device **devs, int ndev);
+
+#endif
+
+#ifdef HAVE_PIPE_LOADER_DRM
+
+/**
+ * Get a list of known DRM devices.
+ *
+ * This function is platform-specific.
+ *
+ * \sa pipe_loader_probe
+ */
+int
+pipe_loader_drm_probe(struct pipe_loader_device **devs, int ndev);
+
+/**
+ * Initialize a DRM device in an already opened fd.
+ *
+ * This function is platform-specific.
+ *
+ * \sa pipe_loader_probe
+ */
+boolean
+pipe_loader_drm_probe_fd(struct pipe_loader_device **dev, int fd);
+
+#endif
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* PIPE_LOADER_H */