diff options
Diffstat (limited to 'drivers/gpu/drm/drm_aperture.c')
| -rw-r--r-- | drivers/gpu/drm/drm_aperture.c | 348 |
1 files changed, 0 insertions, 348 deletions
diff --git a/drivers/gpu/drm/drm_aperture.c b/drivers/gpu/drm/drm_aperture.c deleted file mode 100644 index 9335d9d6cf9a..000000000000 --- a/drivers/gpu/drm/drm_aperture.c +++ /dev/null @@ -1,348 +0,0 @@ -// SPDX-License-Identifier: MIT - -#include <linux/device.h> -#include <linux/fb.h> -#include <linux/list.h> -#include <linux/mutex.h> -#include <linux/pci.h> -#include <linux/platform_device.h> /* for firmware helpers */ -#include <linux/slab.h> -#include <linux/types.h> -#include <linux/vgaarb.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 int remove_conflicting_framebuffers(struct pci_dev *pdev) - * { - * bool primary = false; - * resource_size_t base, size; - * int ret; - * - * base = pci_resource_start(pdev, 0); - * size = pci_resource_len(pdev, 0); - * #ifdef CONFIG_X86 - * primary = pdev->resource[PCI_ROM_RESOURCE].flags & IORESOURCE_ROM_SHADOW; - * #endif - * - * return drm_aperture_remove_conflicting_framebuffers(base, size, primary, - * "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 achived - * 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 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. - */ - -struct drm_aperture { - struct drm_device *dev; - resource_size_t base; - resource_size_t size; - struct list_head lh; - void (*detach)(struct drm_device *dev); -}; - -static LIST_HEAD(drm_apertures); -static DEFINE_MUTEX(drm_apertures_lock); - -static bool overlap(resource_size_t base1, resource_size_t end1, - resource_size_t base2, resource_size_t end2) -{ - return (base1 < end2) && (end1 > base2); -} - -static void devm_aperture_acquire_release(void *data) -{ - struct drm_aperture *ap = data; - bool detached = !ap->dev; - - if (detached) - return; - - mutex_lock(&drm_apertures_lock); - list_del(&ap->lh); - mutex_unlock(&drm_apertures_lock); -} - -static int devm_aperture_acquire(struct drm_device *dev, - resource_size_t base, resource_size_t size, - void (*detach)(struct drm_device *)) -{ - size_t end = base + size; - struct list_head *pos; - struct drm_aperture *ap; - - mutex_lock(&drm_apertures_lock); - - list_for_each(pos, &drm_apertures) { - ap = container_of(pos, struct drm_aperture, lh); - if (overlap(base, end, ap->base, ap->base + ap->size)) { - mutex_unlock(&drm_apertures_lock); - return -EBUSY; - } - } - - ap = devm_kzalloc(dev->dev, sizeof(*ap), GFP_KERNEL); - if (!ap) { - mutex_unlock(&drm_apertures_lock); - return -ENOMEM; - } - - ap->dev = dev; - ap->base = base; - ap->size = size; - ap->detach = detach; - INIT_LIST_HEAD(&ap->lh); - - list_add(&ap->lh, &drm_apertures); - - mutex_unlock(&drm_apertures_lock); - - return devm_add_action_or_reset(dev->dev, devm_aperture_acquire_release, ap); -} - -static void drm_aperture_detach_firmware(struct drm_device *dev) -{ - struct platform_device *pdev = to_platform_device(dev->dev); - - /* - * Remove the device from the device hierarchy. This is the right thing - * to do for firmware-based DRM drivers, such as EFI, VESA or VGA. After - * the new driver takes over the hardware, the firmware device's state - * will be lost. - * - * For non-platform devices, a new callback would be required. - * - * If the aperture helpers ever need to handle native drivers, this call - * would only have to unplug the DRM device, so that the hardware device - * stays around after detachment. - */ - platform_device_unregister(pdev); -} - -/** - * 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) -{ - if (drm_WARN_ON(dev, !dev_is_platform(dev->dev))) - return -EINVAL; - - return devm_aperture_acquire(dev, base, size, drm_aperture_detach_firmware); -} -EXPORT_SYMBOL(devm_aperture_acquire_from_firmware); - -static void drm_aperture_detach_drivers(resource_size_t base, resource_size_t size) -{ - resource_size_t end = base + size; - struct list_head *pos, *n; - - mutex_lock(&drm_apertures_lock); - - list_for_each_safe(pos, n, &drm_apertures) { - struct drm_aperture *ap = - container_of(pos, struct drm_aperture, lh); - struct drm_device *dev = ap->dev; - - if (WARN_ON_ONCE(!dev)) - continue; - - if (!overlap(base, end, ap->base, ap->base + ap->size)) - continue; - - ap->dev = NULL; /* detach from device */ - list_del(&ap->lh); - - ap->detach(dev); - } - - mutex_unlock(&drm_apertures_lock); -} - -/** - * 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 - * @primary: also kick vga16fb if present - * @name: requesting driver name - * - * This function removes graphics device drivers which use 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, - bool primary, const char *name) -{ -#if IS_REACHABLE(CONFIG_FB) - struct apertures_struct *a; - int ret; - - a = alloc_apertures(1); - if (!a) - return -ENOMEM; - - a->ranges[0].base = base; - a->ranges[0].size = size; - - ret = remove_conflicting_framebuffers(a, name, primary); - kfree(a); - - if (ret) - return ret; -#endif - - drm_aperture_detach_drivers(base, size); - - return 0; -} -EXPORT_SYMBOL(drm_aperture_remove_conflicting_framebuffers); - -/** - * drm_aperture_remove_conflicting_pci_framebuffers - remove existing framebuffers for PCI devices - * @pdev: PCI device - * @name: requesting driver name - * - * This function removes graphics device drivers using memory range configured - * for any of @pdev's memory bars. The function assumes that 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 char *name) -{ - resource_size_t base, size; - int bar, 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); - } - - /* - * WARNING: Apparently we must kick fbdev drivers before vgacon, - * otherwise the vga fbdev driver falls over. - */ -#if IS_REACHABLE(CONFIG_FB) - ret = remove_conflicting_pci_framebuffers(pdev, name); -#endif - if (ret == 0) - ret = vga_remove_vgacon(pdev); - return ret; -} -EXPORT_SYMBOL(drm_aperture_remove_conflicting_pci_framebuffers); |