354 строки
10 KiB
C
354 строки
10 KiB
C
// 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 const struct drm_driver example_driver = {
|
|
* ...
|
|
* };
|
|
*
|
|
* 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 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 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
|
|
* @req_driver: requesting DRM driver
|
|
*
|
|
* 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 struct drm_driver *req_driver)
|
|
{
|
|
#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, req_driver->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
|
|
* @req_driver: requesting DRM driver
|
|
*
|
|
* 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 struct drm_driver *req_driver)
|
|
{
|
|
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, req_driver->name);
|
|
#endif
|
|
if (ret == 0)
|
|
ret = vga_remove_vgacon(pdev);
|
|
return ret;
|
|
}
|
|
EXPORT_SYMBOL(drm_aperture_remove_conflicting_pci_framebuffers);
|