[PATCH 1/2] drm/aperture: Split conflicting platform driver removal

Alex Williamson
2022-06-06T17:53:54Z

Split the removal of platform drivers conflicting with PCI resources from
drm_aperture_remove_conflicting_pci_framebuffers() to support both non-DRM
callers and better modularity. This is intended to support the vfio-pci
driver, which can acquire ownership of PCI graphics devices, but is not
itself a DRM or FB driver, and therefore has no Kconfig dependencies. The
remaining actions of drm_aperture_remove_conflicting_pci_framebuffers() are
already exported from their respective subsystems, therefore this allows
vfio-pci to separate each set of conflicts independently based on the
configured features.

Reported-by: Laszlo Ersek <lersek@redhat.com>
Tested-by: Laszlo Ersek <lersek@redhat.com>
Suggested-by: Gerd Hoffmann <kraxel@redhat.com>
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
---
drivers/gpu/drm/drm_aperture.c | 33 ++++++++++++++++++++++++---------
include/drm/drm_aperture.h | 2 ++
2 files changed, 26 insertions(+), 9 deletions(-)

diff --git a/drivers/gpu/drm/drm_aperture.c b/drivers/gpu/drm/drm_aperture.c
index 74bd4a76b253..5b2500f7fb8b 100644
--- a/drivers/gpu/drm/drm_aperture.c
+++ b/drivers/gpu/drm/drm_aperture.c
@@ -313,6 +313,28 @@ int drm_aperture_remove_conflicting_framebuffers(resource_size_t base, resource_
}
EXPORT_SYMBOL(drm_aperture_remove_conflicting_framebuffers);

+/**
+ * drm_aperture_detach_platform_drivers - detach platform drivers conflicting with PCI device
+ * @pdev: PCI device
+ *
+ * This function detaches platform drivers with resource conflicts to the memory
+ * bars of the provided @pdev.
+ */
+void drm_aperture_detach_platform_drivers(struct pci_dev *pdev)
+{
+ resource_size_t base, size;
+ int bar;
+
+ for (bar = 0; bar < PCI_STD_NUM_BARS; ++bar) {
+ if (!(pci_resource_flags(pdev, bar) & IORESOURCE_MEM))
+ continue;
+ base = pci_resource_start(pdev, bar);
+ size = pci_resource_len(pdev, bar);
+ drm_aperture_detach_drivers(base, size);
+ }
+}
+EXPORT_SYMBOL(drm_aperture_detach_platform_drivers);
+
/**
* drm_aperture_remove_conflicting_pci_framebuffers - remove existing framebuffers for PCI devices
* @pdev: PCI device
@@ -328,16 +350,9 @@ EXPORT_SYMBOL(drm_aperture_remove_conflicting_framebuffers);
int drm_aperture_remove_conflicting_pci_framebuffers(struct pci_dev *pdev,
const struct drm_driver *req_driver)
{
- resource_size_t base, size;
- int bar, ret = 0;
+ int ret = 0;

- for (bar = 0; bar < PCI_STD_NUM_BARS; ++bar) {
- if (!(pci_resource_flags(pdev, bar) & IORESOURCE_MEM))
- continue;
- base = pci_resource_start(pdev, bar);
- size = pci_resource_len(pdev, bar);
- drm_aperture_detach_drivers(base, size);
- }
+ drm_aperture_detach_platform_drivers(pdev);

/*
* WARNING: Apparently we must kick fbdev drivers before vgacon,
diff --git a/include/drm/drm_aperture.h b/include/drm/drm_aperture.h
index 7096703c3949..53fd36fa258e 100644
--- a/include/drm/drm_aperture.h
+++ b/include/drm/drm_aperture.h
@@ -15,6 +15,8 @@ int devm_aperture_acquire_from_firmware(struct drm_device *dev, resource_size_t
int drm_aperture_remove_conflicting_framebuffers(resource_size_t base, resource_size_t size,
bool primary, const struct drm_driver *req_driver);

+void drm_aperture_detach_platform_drivers(struct pci_dev *pdev);
+
int drm_aperture_remove_conflicting_pci_framebuffers(struct pci_dev *pdev,
const struct drm_driver *req_driver);