// 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 <linux/aperture.h>
+#include <linux/platform_device.h>
#include <drm/drm_aperture.h>
#include <drm/drm_drv.h>
* 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.
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;
- 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);
+ pdev = to_platform_device(dev->dev);
- ap->detach(dev);
- }
-
- mutex_unlock(&drm_apertures_lock);
+ 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
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;
+ return aperture_remove_conflicting_devices(base, size, primary, req_driver->name);
}
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;
-
- /*
- * 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);
- if (ret)
- return ret;
-#endif
- ret = vga_remove_vgacon(pdev);
- if (ret)
- return ret;
-
- 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);
- }
-
- return 0;
+ return aperture_remove_conflicting_pci_devices(pdev, req_driver->name);
}
EXPORT_SYMBOL(drm_aperture_remove_conflicting_pci_framebuffers);
--- /dev/null
+// SPDX-License-Identifier: MIT
+
+#include <linux/aperture.h>
+#include <linux/device.h>
+#include <linux/fb.h> /* for old fbdev helpers */
+#include <linux/list.h>
+#include <linux/mutex.h>
+#include <linux/pci.h>
+#include <linux/platform_device.h>
+#include <linux/slab.h>
+#include <linux/types.h>
+#include <linux/vgaarb.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. Aperture functions manage
+ * ownership of framebuffer memory and hand-over between drivers.
+ *
+ * Graphics drivers should call aperture_remove_conflicting_devices()
+ * at the top of their probe function. The function removes any generic
+ * driver that is currently associated with the given framebuffer memory.
+ * An example for a graphics device on the platform bus is shown below.
+ *
+ * .. code-block:: c
+ *
+ * static int example_probe(struct platform_device *pdev)
+ * {
+ * struct resource *mem;
+ * resource_size_t base, size;
+ * int ret;
+ *
+ * mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+ * if (!mem)
+ * return -ENODEV;
+ * base = mem->start;
+ * size = resource_size(mem);
+ *
+ * ret = aperture_remove_conflicting_devices(base, size, false, "example");
+ * if (ret)
+ * return ret;
+ *
+ * // Initialize the hardware
+ * ...
+ *
+ * return 0;
+ * }
+ *
+ * static const struct platform_driver example_driver = {
+ * .probe = example_probe,
+ * ...
+ * };
+ *
+ * The given example reads the platform device's I/O-memory range from the
+ * device instance. An active framebuffer will be located within this range.
+ * The call to aperture_remove_conflicting_devices() releases drivers that
+ * have previously claimed ownership of the range and are currently driving
+ * output on the framebuffer. If successful, the new driver can take over
+ * the device.
+ *
+ * While the given example uses a platform device, the aperture helpers work
+ * with every bus that has an addressable framebuffer. In the case of PCI,
+ * device drivers can also call aperture_remove_conflicting_pci_devices() and
+ * let the function detect the apertures automatically. Device drivers without
+ * knowledge of the framebuffer's location can call
+ * aperture_remove_all_conflicting_devices(), which removes all known devices.
+ *
+ * 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
+ * framebuffer apertures. Ownership of the framebuffer memory is achieved
+ * by calling devm_aperture_acquire_for_platform_device(). If successful, the
+ * driveris 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 generic_probe(struct platform_device *pdev)
+ * {
+ * struct resource *mem;
+ * resource_size_t base, size;
+ *
+ * mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+ * if (!mem)
+ * return -ENODEV;
+ * base = mem->start;
+ * size = resource_size(mem);
+ *
+ * ret = devm_aperture_acquire_for_platform_device(pdev, base, size);
+ * if (ret)
+ * return ret;
+ *
+ * // Initialize the hardware
+ * ...
+ *
+ * return 0;
+ * }
+ *
+ * static int generic_remove(struct platform_device *)
+ * {
+ * // Hot-unplug the device
+ * ...
+ *
+ * return 0;
+ * }
+ *
+ * static const struct platform_driver generic_driver = {
+ * .probe = generic_probe,
+ * .remove = generic_remove,
+ * ...
+ * };
+ *
+ * The similar to the previous example, the generic driver claims ownership
+ * of the framebuffer memory from its probe function. This will fail if the
+ * memory range, or parts of it, is already owned by another driver.
+ *
+ * If successful, the generic driver is now subject to forced removal by
+ * another driver. This only works for platform drivers that support hot
+ * unplugging. When a driver calls aperture_remove_conflicting_devices()
+ * et al for the registered framebuffer range, the aperture helpers call
+ * platform_device_unregister() and the generic driver unloads itself. The
+ * generic driver also has to provide a remove function to make this work.
+ * Once hot unplugged fro mhardware, it may not access the device's
+ * registers, framebuffer memory, ROM, etc afterwards.
+ */
+
+struct aperture_range {
+ struct device *dev;
+ resource_size_t base;
+ resource_size_t size;
+ struct list_head lh;
+ void (*detach)(struct device *dev);
+};
+
+static LIST_HEAD(apertures);
+static DEFINE_MUTEX(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 aperture_range *ap = data;
+ bool detached = !ap->dev;
+
+ if (detached)
+ return;
+
+ mutex_lock(&apertures_lock);
+ list_del(&ap->lh);
+ mutex_unlock(&apertures_lock);
+}
+
+static int devm_aperture_acquire(struct device *dev,
+ resource_size_t base, resource_size_t size,
+ void (*detach)(struct device *))
+{
+ size_t end = base + size;
+ struct list_head *pos;
+ struct aperture_range *ap;
+
+ mutex_lock(&apertures_lock);
+
+ list_for_each(pos, &apertures) {
+ ap = container_of(pos, struct aperture_range, lh);
+ if (overlap(base, end, ap->base, ap->base + ap->size)) {
+ mutex_unlock(&apertures_lock);
+ return -EBUSY;
+ }
+ }
+
+ ap = devm_kzalloc(dev, sizeof(*ap), GFP_KERNEL);
+ if (!ap) {
+ mutex_unlock(&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, &apertures);
+
+ mutex_unlock(&apertures_lock);
+
+ return devm_add_action_or_reset(dev, devm_aperture_acquire_release, ap);
+}
+
+static void aperture_detach_platform_device(struct device *dev)
+{
+ struct platform_device *pdev = to_platform_device(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_for_platform_device - Acquires ownership of an aperture
+ * on behalf of a platform device.
+ * @pdev: the platform device to own the aperture
+ * @base: the aperture's byte offset in physical memory
+ * @size: the aperture size in bytes
+ *
+ * Installs the given device as the new owner of the aperture. The function
+ * expects the aperture to be provided by a platform device. If another
+ * driver takes over ownership of the aperture, aperture helpers will then
+ * unregister the platform device automatically. All acquired apertures are
+ * released automatically when the underlying device goes away.
+ *
+ * The function fails if the aperture, or parts of it, is currently
+ * owned by another device. To evict current owners, callers should use
+ * remove_conflicting_devices() et al. before calling this function.
+ *
+ * Returns:
+ * 0 on success, or a negative errno value otherwise.
+ */
+int devm_aperture_acquire_for_platform_device(struct platform_device *pdev,
+ resource_size_t base,
+ resource_size_t size)
+{
+ return devm_aperture_acquire(&pdev->dev, base, size, aperture_detach_platform_device);
+}
+EXPORT_SYMBOL(devm_aperture_acquire_for_platform_device);
+
+static void aperture_detach_devices(resource_size_t base, resource_size_t size)
+{
+ resource_size_t end = base + size;
+ struct list_head *pos, *n;
+
+ mutex_lock(&apertures_lock);
+
+ list_for_each_safe(pos, n, &apertures) {
+ struct aperture_range *ap = container_of(pos, struct aperture_range, lh);
+ struct 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(&apertures_lock);
+}
+
+/**
+ * aperture_remove_conflicting_devices - remove devices in the given range
+ * @base: the aperture's base address in physical memory
+ * @size: aperture size in bytes
+ * @primary: also kick vga16fb if present; only relevant for VGA devices
+ * @name: a descriptive name of the requesting driver
+ *
+ * This function removes devices that own apertures within @base and @size.
+ *
+ * Returns:
+ * 0 on success, or a negative errno code otherwise
+ */
+int aperture_remove_conflicting_devices(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
+
+ aperture_detach_devices(base, size);
+
+ return 0;
+}
+EXPORT_SYMBOL(aperture_remove_conflicting_devices);
+
+/**
+ * aperture_remove_conflicting_pci_devices - remove existing framebuffers for PCI devices
+ * @pdev: PCI device
+ * @name: a descriptive name of the requesting driver
+ *
+ * This function removes devices that own apertures within any of @pdev's
+ * memory bars. The function assumes that PCI device with shadowed ROM
+ * drives a primary display and therefore kicks out vga16fb as well.
+ *
+ * Returns:
+ * 0 on success, or a negative errno code otherwise
+ */
+int aperture_remove_conflicting_pci_devices(struct pci_dev *pdev, const char *name)
+{
+ resource_size_t base, size;
+ int bar, ret;
+
+ /*
+ * 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);
+ if (ret)
+ return ret;
+#endif
+ ret = vga_remove_vgacon(pdev);
+ if (ret)
+ return ret;
+
+ 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);
+ aperture_detach_devices(base, size);
+ }
+
+ return 0;
+
+}
+EXPORT_SYMBOL(aperture_remove_conflicting_pci_devices);
projects / kernel.git / commitdiff