[PATCH i-g-t v11 4/6] lib/intel_multigpu: Add multi_fork_foreach_gpu_chip

[Kamil Konieczny]

Create macro for testing drm driver in multigpu scenarios with
the help of few new multigpu functions. Also while at this,
add documentation for public functions and use new helper in
existing multi-gpu macro.

v2: corrected description (Kamil), rebased on corrected patches
  after Dominik review
v3: corrected descriptions, renamed function to print_gpus
  and did small refactoring (Kamil)
  fixed typo in function name (Dominik)
v4: fixed typos (Dominik)
v10: rename new macro into multi_fork_foreach_gpu_chip (Zbigniew)

Cc: "Zbigniew Kempczyński" <zbigniew.kempczynski at intel.com>
Reviewed-by: "Dominik Karol Piątkowski" <dominik.karol.piatkowski at intel.com>
Signed-off-by: Kamil Konieczny <kamil.konieczny at linux.intel.com>
---
 lib/intel_multigpu.c | 72 ++++++++++++++++++++++++++++++++++++++++++++
 lib/intel_multigpu.h | 10 ++++++
 2 files changed, 82 insertions(+)

diff --git a/lib/intel_multigpu.c b/lib/intel_multigpu.c
index c4e7cf542..8b7d6f3fc 100644
--- a/lib/intel_multigpu.c
+++ b/lib/intel_multigpu.c
@@ -4,6 +4,7 @@
  */
 
 #include "drmtest.h"
+#include "i915/gem.h"
 #include "igt_core.h"
 #include "igt_device_scan.h"
 #include "intel_multigpu.h"
@@ -60,3 +61,74 @@ void gem_require_multigpu(int gpus_wanted)
 	print_gpus(gpus_wanted, gpu_filters);
 	igt_skip_on(gpu_filters < gpus_wanted);
 }
+
+/**
+ * multigpu_acquire_view:
+ * @gpus_wanted: minimum number of GPUs required
+ * @chipset: chipset, e.g. DRIVER_XE or DRIVER_INTEL
+ *
+ * Function prepares filtered view for GPU cards with given chipset.
+ * On error skips and prints available GPUs found on PCI bus.
+ * Returns: number of GPUs found
+ */
+int multigpu_acquire_view(int gpus_wanted, unsigned int chipset)
+{
+	int gpu_count = drm_prepare_filtered_multigpu(chipset);
+
+	igt_assert(gpus_wanted > 1);
+	if (gpu_count >= gpus_wanted)
+		return gpu_count;
+
+	print_gpus(gpus_wanted, gpu_count);
+	igt_skip_on(gpu_count < gpus_wanted);
+
+	return gpu_count; /* non-reachable */
+}
+
+/**
+ * multigpu_open_another:
+ * @idx: index of GPU card, starting from 0
+ * @chipset: chipset, e.g. DRIVER_XE or DRIVER_INTEL
+ *
+ * Function opens GPU card with drm_open_driver_another(). For i915 it checks
+ * if opened card is functional. Skips on errors.
+ *
+ * Returns: opened fd for @idx card
+ */
+int multigpu_open_another(int idx, unsigned int chipset)
+{
+	int fd;
+
+	igt_assert(idx >= 0);
+	fd = drm_open_driver_another(idx, chipset);
+
+	if (chipset == DRIVER_INTEL)
+		igt_require_gem(fd);
+
+	return fd;
+}
+
+/**
+ * multigpu_open_filtered_card:
+ * @idx: index of GPU card, starting from 0
+ * @chipset: chipset, e.g. DRIVER_XE or DRIVER_INTEL
+ *
+ * Function opens GPU card prepared with filtered view. It also checks if
+ * opened card agrees with desired chipset or checks if opened card is
+ * functional. Skips on errors.
+ *
+ * Returns: opened fd for @idx card
+ */
+int multigpu_open_filtered_card(int idx, unsigned int chipset)
+{
+	int fd;
+
+	igt_assert(idx >= 0);
+	fd = drm_open_filtered_card(idx);
+	if (chipset == DRIVER_XE)
+		igt_require_xe(fd);
+	else if (chipset == DRIVER_INTEL)
+		igt_require_gem(fd);
+
+	return fd;
+}
diff --git a/lib/intel_multigpu.h b/lib/intel_multigpu.h
index 5acfcd5f6..a99e7a85e 100644
--- a/lib/intel_multigpu.h
+++ b/lib/intel_multigpu.h
@@ -12,6 +12,10 @@
 void gem_require_multigpu(int count);
 int gem_multigpu_count_class(int chipset);
 
+int multigpu_acquire_view(int min_gpus_wanted, unsigned int chipset);
+int multigpu_open_another(int idx, unsigned int chipset);
+int multigpu_open_filtered_card(int idx, unsigned int chipset);
+
 #define igt_foreach_gpu(fd__, chipset__) \
 	for (int igt_unique(i) = 0, fd__; \
 		(fd__ = __drm_open_driver_another(igt_unique(i)++, chipset__)) >= 0; \
@@ -23,4 +27,10 @@ int gem_multigpu_count_class(int chipset);
 			__fd >= 0; \
 			drm_close_driver(__fd), __fd = -1) \
 
+#define multi_fork_foreach_gpu_chip(__fd, __gpu_index, __chipset) \
+	igt_multi_fork(__gpu_index, multigpu_acquire_view(2, __chipset)) \
+		for (int __fd = multigpu_open_filtered_card(__gpu_index, __chipset); \
+			__fd >= 0; \
+			drm_close_driver(__fd), __fd = -1) \
+
 #endif /* __INTEL_MULTIGPU_H */
-- 
2.42.0