[Intel-gfx] [PATCH] drm/i915: Add fault injection support

[Imre Deak]

Add support for forcing an error at selected places in the driver. As an
example add 3 options to fail during driver loading.

Requested by Chris.

CC: Chris Wilson <chris at chris-wilson.co.uk>
Signed-off-by: Imre Deak <imre.deak at intel.com>
---

[This depends on
https://lists.freedesktop.org/archives/intel-gfx/2016-March/089597.html]

 drivers/gpu/drm/i915/i915_dma.c    | 9 +++++++++
 drivers/gpu/drm/i915/i915_drv.h    | 4 ++++
 drivers/gpu/drm/i915/i915_params.c | 6 ++++++
 drivers/gpu/drm/i915/i915_params.h | 1 +
 4 files changed, 20 insertions(+)

diff --git a/drivers/gpu/drm/i915/i915_dma.c b/drivers/gpu/drm/i915/i915_dma.c
index b1dbf1b..d12ae0b 100644
--- a/drivers/gpu/drm/i915/i915_dma.c
+++ b/drivers/gpu/drm/i915/i915_dma.c
@@ -950,6 +950,9 @@ static int i915_driver_init_early(struct drm_i915_private *dev_priv,
 	struct intel_device_info *device_info;
 	int ret = 0;
 
+	if (i915.inject_fault & I915_FAULT_INIT_EARLY)
+		return -ENODEV;
+
 	dev_priv->dev = dev;
 
 	/* Setup the write-once "constant" device info */
@@ -1064,6 +1067,9 @@ static int i915_driver_init_mmio(struct drm_i915_private *dev_priv)
 	struct drm_device *dev = dev_priv->dev;
 	int ret;
 
+	if (i915.inject_fault & I915_FAULT_INIT_MMIO)
+		return -ENODEV;
+
 	if (i915_get_bridge_dev(dev))
 		return -EIO;
 
@@ -1107,6 +1113,9 @@ static int i915_driver_init_hw(struct drm_i915_private *dev_priv)
 	uint32_t aperture_size;
 	int ret;
 
+	if (i915.inject_fault & I915_FAULT_INIT_HW)
+		return -ENODEV;
+
 	intel_device_info_runtime_init(dev);
 
 	ret = i915_gem_gtt_init(dev);
diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
index f62b6d1..5122ed9 100644
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -98,6 +98,10 @@
 #define I915_STATE_WARN_ON(x)						\
 	I915_STATE_WARN((x), "%s", "WARN_ON(" __stringify(x) ")")
 
+#define I915_FAULT_INIT_EARLY	0x0001
+#define I915_FAULT_INIT_MMIO	0x0002
+#define I915_FAULT_INIT_HW	0x0004
+
 static inline const char *yesno(bool v)
 {
 	return v ? "yes" : "no";
diff --git a/drivers/gpu/drm/i915/i915_params.c b/drivers/gpu/drm/i915/i915_params.c
index 278c9c4..21f8dd3 100644
--- a/drivers/gpu/drm/i915/i915_params.c
+++ b/drivers/gpu/drm/i915/i915_params.c
@@ -56,6 +56,7 @@ struct i915_params i915 __read_mostly = {
 	.edp_vswing = 0,
 	.enable_guc_submission = false,
 	.guc_log_level = -1,
+	.inject_fault = 0,
 };
 
 module_param_named(modeset, i915.modeset, int, 0400);
@@ -201,3 +202,8 @@ MODULE_PARM_DESC(enable_guc_submission, "Enable GuC submission (default:false)")
 module_param_named(guc_log_level, i915.guc_log_level, int, 0400);
 MODULE_PARM_DESC(guc_log_level,
 	"GuC firmware logging level (-1:disabled (default), 0-3:enabled)");
+
+module_param_named(inject_fault, i915.inject_fault, uint, 0600);
+MODULE_PARM_DESC(inject_fault,
+	"Force an error at selected points "
+	"(0:disabled, 0x1:INIT_EARLY, 0x2:INIT_MMIO, 0x4:INIT_HW)");
diff --git a/drivers/gpu/drm/i915/i915_params.h b/drivers/gpu/drm/i915/i915_params.h
index bd5026b..2989a48 100644
--- a/drivers/gpu/drm/i915/i915_params.h
+++ b/drivers/gpu/drm/i915/i915_params.h
@@ -59,6 +59,7 @@ struct i915_params {
 	bool enable_guc_submission;
 	bool verbose_state_checks;
 	bool nuclear_pageflip;
+	unsigned int inject_fault;
 };
 
 extern struct i915_params i915 __read_mostly;
-- 
2.5.0