[PATCH] drm/amdgpu: Add sysfs file for VBIOS

[Kent Russell]

This won't change after initialization, so we can add the information
when we parse the atombios information. This ensures that we can find
out the VBIOS, even when the dmesg buffer fills up, and makes it easier
to associate which VBIOS is for which GPU on mGPU configurations. Set
the size to 20 characters in case of some weird VBIOS suffix that exceeds
the expected 17 character format (3-8-3\0)

Signed-off-by: Kent Russell <kent.russell at amd.com>
---
 drivers/gpu/drm/amd/amdgpu/amdgpu_device.c | 23 +++++++++++++++++++++++
 drivers/gpu/drm/amd/amdgpu/atom.c          |  5 ++++-
 drivers/gpu/drm/amd/amdgpu/atom.h          |  1 +
 3 files changed, 28 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
index a1f9424..f40be71 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
@@ -888,6 +888,20 @@ static uint32_t cail_ioreg_read(struct card_info *info, uint32_t reg)
 	return r;
 }
 
+static ssize_t amdgpu_atombios_get_vbios_version(struct device *dev,
+						 struct device_attribute *attr,
+						 char *buf)
+{
+	struct drm_device *ddev = dev_get_drvdata(dev);
+	struct amdgpu_device *adev = ddev->dev_private;
+	struct atom_context *ctx = adev->mode_info.atom_context;
+
+	return snprintf(buf, PAGE_SIZE, "%s\n", ctx->vbios_version);
+}
+
+static DEVICE_ATTR(vbios_version, 0444, amdgpu_atombios_get_vbios_version,
+		   NULL);
+
 /**
  * amdgpu_atombios_fini - free the driver info and callbacks for atombios
  *
@@ -907,6 +921,7 @@ static void amdgpu_atombios_fini(struct amdgpu_device *adev)
 	adev->mode_info.atom_context = NULL;
 	kfree(adev->mode_info.atom_card_info);
 	adev->mode_info.atom_card_info = NULL;
+	device_remove_file(adev->dev, &dev_attr_vbios_version);
 }
 
 /**
@@ -923,6 +938,7 @@ static int amdgpu_atombios_init(struct amdgpu_device *adev)
 {
 	struct card_info *atom_card_info =
 	    kzalloc(sizeof(struct card_info), GFP_KERNEL);
+	int ret;
 
 	if (!atom_card_info)
 		return -ENOMEM;
@@ -959,6 +975,13 @@ static int amdgpu_atombios_init(struct amdgpu_device *adev)
 		amdgpu_atombios_scratch_regs_init(adev);
 		amdgpu_atombios_allocate_fb_scratch(adev);
 	}
+
+	ret = device_create_file(adev->dev, &dev_attr_vbios_version);
+	if (ret) {
+		DRM_ERROR("Failed to create device file for VBIOS version\n");
+		return ret;
+	}
+
 	return 0;
 }
 
diff --git a/drivers/gpu/drm/amd/amdgpu/atom.c b/drivers/gpu/drm/amd/amdgpu/atom.c
index d69aa2e..69500a8 100644
--- a/drivers/gpu/drm/amd/amdgpu/atom.c
+++ b/drivers/gpu/drm/amd/amdgpu/atom.c
@@ -1343,8 +1343,11 @@ struct atom_context *amdgpu_atom_parse(struct card_info *card, void *bios)
 		idx = 0x80;
 
 	str = CSTR(idx);
-	if (*str != '\0')
+	if (*str != '\0') {
 		pr_info("ATOM BIOS: %s\n", str);
+		strlcpy(ctx->vbios_version, str, sizeof(ctx->vbios_version));
+	}
+
 
 	return ctx;
 }
diff --git a/drivers/gpu/drm/amd/amdgpu/atom.h b/drivers/gpu/drm/amd/amdgpu/atom.h
index ddd8045..a391709 100644
--- a/drivers/gpu/drm/amd/amdgpu/atom.h
+++ b/drivers/gpu/drm/amd/amdgpu/atom.h
@@ -140,6 +140,7 @@ struct atom_context {
 	int io_mode;
 	uint32_t *scratch;
 	int scratch_size_bytes;
+	char vbios_version[20];
 };
 
 extern int amdgpu_atom_debug;
-- 
2.7.4