drm/amdgpu: Add PCIe replay count sysfs file

Add a sysfs file for reporting the number of PCIe replays (NAKs). This
returns the sum of NAKs received and NAKs generated

Signed-off-by: Kent Russell <kent.russell@amd.com>
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

1 files changed, 29 insertions, 0 deletions

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
index 0237513086e8..665764ff7eb7 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
@@ -97,6 +97,28 @@ static const char *amdgpu_asic_name[] = {
 	"LAST",
 };
 
+/**
+ * DOC: pcie_replay_count
+ *
+ * The amdgpu driver provides a sysfs API for reporting the total number
+ * of PCIe replays (NAKs)
+ * The file pcie_replay_count is used for this and returns the total
+ * number of replays as a sum of the NAKs generated and NAKs received
+ */
+
+static ssize_t amdgpu_device_get_pcie_replay_count(struct device *dev,
+		struct device_attribute *attr, char *buf)
+{
+	struct drm_device *ddev = dev_get_drvdata(dev);
+	struct amdgpu_device *adev = ddev->dev_private;
+	uint64_t cnt = amdgpu_asic_get_pcie_replay_count(adev);
+
+	return snprintf(buf, PAGE_SIZE, "%llu\n", cnt);
+}
+
+static DEVICE_ATTR(pcie_replay_count, S_IRUGO,
+		amdgpu_device_get_pcie_replay_count, NULL);
+
 static void amdgpu_device_get_pcie_info(struct amdgpu_device *adev);
 
 /**
@@ -2721,6 +2743,12 @@ fence_driver_init:
 	/* must succeed. */
 	amdgpu_ras_post_init(adev);
 
+	r = device_create_file(adev->dev, &dev_attr_pcie_replay_count);
+	if (r) {
+		dev_err(adev->dev, "Could not create pcie_replay_count");
+		return r;
+	}
+
 	return 0;
 
 failed:
@@ -2784,6 +2812,7 @@ void amdgpu_device_fini(struct amdgpu_device *adev)
 	adev->rmmio = NULL;
 	amdgpu_device_doorbell_fini(adev);
 	amdgpu_debugfs_regs_cleanup(adev);
+	device_remove_file(adev->dev, &dev_attr_pcie_replay_count);
 }