+++ /dev/null
-// SPDX-License-Identifier: MIT
-
-#include <linux/aperture.h>
-#include <linux/platform_device.h>
-
-#include <drm/drm_aperture.h>
-#include <drm/drm_drv.h>
-#include <drm/drm_print.h>
-
-/**
- * DOC: overview
- *
- * A graphics device might be supported by different drivers, but only one
- * driver can be active at any given time. Many systems load a generic
- * graphics drivers, such as EFI-GOP or VESA, early during the boot process.
- * During later boot stages, they replace the generic driver with a dedicated,
- * hardware-specific driver. To take over the device the dedicated driver
- * first has to remove the generic driver. DRM aperture functions manage
- * ownership of DRM framebuffer memory and hand-over between drivers.
- *
- * DRM drivers should call drm_aperture_remove_conflicting_framebuffers()
- * at the top of their probe function. The function removes any generic
- * driver that is currently associated with the given framebuffer memory.
- * If the framebuffer is located at PCI BAR 0, the rsp code looks as in the
- * example given below.
- *
- * .. code-block:: c
- *
- * static const struct drm_driver example_driver = {
- * ...
- * };
- *
- * static int remove_conflicting_framebuffers(struct pci_dev *pdev)
- * {
- * resource_size_t base, size;
- * int ret;
- *
- * base = pci_resource_start(pdev, 0);
- * size = pci_resource_len(pdev, 0);
- *
- * return drm_aperture_remove_conflicting_framebuffers(base, size,
- * &example_driver);
- * }
- *
- * static int probe(struct pci_dev *pdev)
- * {
- * int ret;
- *
- * // Remove any generic drivers...
- * ret = remove_conflicting_framebuffers(pdev);
- * if (ret)
- * return ret;
- *
- * // ... and initialize the hardware.
- * ...
- *
- * drm_dev_register();
- *
- * return 0;
- * }
- *
- * PCI device drivers should call
- * drm_aperture_remove_conflicting_pci_framebuffers() and let it detect the
- * framebuffer apertures automatically. Device drivers without knowledge of
- * the framebuffer's location shall call drm_aperture_remove_framebuffers(),
- * which removes all drivers for known framebuffer.
- *
- * Drivers that are susceptible to being removed by other drivers, such as
- * generic EFI or VESA drivers, have to register themselves as owners of their
- * given framebuffer memory. Ownership of the framebuffer memory is achieved
- * by calling devm_aperture_acquire_from_firmware(). On success, the driver
- * is the owner of the framebuffer range. The function fails if the
- * framebuffer is already owned by another driver. See below for an example.
- *
- * .. code-block:: c
- *
- * static int acquire_framebuffers(struct drm_device *dev, struct platform_device *pdev)
- * {
- * resource_size_t base, size;
- *
- * mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
- * if (!mem)
- * return -EINVAL;
- * base = mem->start;
- * size = resource_size(mem);
- *
- * return devm_acquire_aperture_from_firmware(dev, base, size);
- * }
- *
- * static int probe(struct platform_device *pdev)
- * {
- * struct drm_device *dev;
- * int ret;
- *
- * // ... Initialize the device...
- * dev = devm_drm_dev_alloc();
- * ...
- *
- * // ... and acquire ownership of the framebuffer.
- * ret = acquire_framebuffers(dev, pdev);
- * if (ret)
- * return ret;
- *
- * drm_dev_register(dev, 0);
- *
- * return 0;
- * }
- *
- * The generic driver is now subject to forced removal by other drivers. This
- * only works for platform drivers that support hot unplug.
- * When a driver calls drm_aperture_remove_conflicting_framebuffers() et al.
- * for the registered framebuffer range, the aperture helpers call
- * platform_device_unregister() and the generic driver unloads itself. It
- * may not access the device's registers, framebuffer memory, ROM, etc
- * afterwards.
- */
-
-/**
- * devm_aperture_acquire_from_firmware - Acquires ownership of a firmware framebuffer
- * on behalf of a DRM driver.
- * @dev: the DRM device to own the framebuffer memory
- * @base: the framebuffer's byte offset in physical memory
- * @size: the framebuffer size in bytes
- *
- * Installs the given device as the new owner of the framebuffer. The function
- * expects the framebuffer to be provided by a platform device that has been
- * set up by firmware. Firmware can be any generic interface, such as EFI,
- * VESA, VGA, etc. If the native hardware driver takes over ownership of the
- * framebuffer range, the firmware state gets lost. Aperture helpers will then
- * unregister the platform device automatically. Acquired apertures are
- * released automatically if the underlying device goes away.
- *
- * The function fails if the framebuffer range, or parts of it, is currently
- * owned by another driver. To evict current owners, callers should use
- * drm_aperture_remove_conflicting_framebuffers() et al. before calling this
- * function. The function also fails if the given device is not a platform
- * device.
- *
- * Returns:
- * 0 on success, or a negative errno value otherwise.
- */
-int devm_aperture_acquire_from_firmware(struct drm_device *dev, resource_size_t base,
- resource_size_t size)
-{
- struct platform_device *pdev;
-
- if (drm_WARN_ON(dev, !dev_is_platform(dev->dev)))
- return -EINVAL;
-
- pdev = to_platform_device(dev->dev);
-
- return devm_aperture_acquire_for_platform_device(pdev, base, size);
-}
-EXPORT_SYMBOL(devm_aperture_acquire_from_firmware);
-
-/**
- * drm_aperture_remove_conflicting_framebuffers - remove existing framebuffers in the given range
- * @base: the aperture's base address in physical memory
- * @size: aperture size in bytes
- * @req_driver: requesting DRM driver
- *
- * This function removes graphics device drivers which use the memory range described by
- * @base and @size.
- *
- * Returns:
- * 0 on success, or a negative errno code otherwise
- */
-int drm_aperture_remove_conflicting_framebuffers(resource_size_t base, resource_size_t size,
- const struct drm_driver *req_driver)
-{
- return aperture_remove_conflicting_devices(base, size, req_driver->name);
-}
-EXPORT_SYMBOL(drm_aperture_remove_conflicting_framebuffers);
-
-/**
- * drm_aperture_remove_conflicting_pci_framebuffers - remove existing framebuffers for PCI devices
- * @pdev: PCI device
- * @req_driver: requesting DRM driver
- *
- * This function removes graphics device drivers using the memory range configured
- * for any of @pdev's memory bars. The function assumes that a PCI device with
- * shadowed ROM drives a primary display and so kicks out vga16fb.
- *
- * Returns:
- * 0 on success, or a negative errno code otherwise
- */
-int drm_aperture_remove_conflicting_pci_framebuffers(struct pci_dev *pdev,
- const struct drm_driver *req_driver)
-{
- return aperture_remove_conflicting_pci_devices(pdev, req_driver->name);
-}
-EXPORT_SYMBOL(drm_aperture_remove_conflicting_pci_framebuffers);
projects / thirdparty / kernel / linux.git / commitdiff
