Add support for coreboot devices. Until now, all devices with system framebuffers were on the platform bus. On systems with a coreboot firmware, the system framebuffer can be represented as coreboot device on the coreboot bus. Handling the related graphics apertures requires new interfaces and a custom way of removing the coreboot device. The core aperture code is independent from the type of device.
Also move around a comment that refers to both, platform and coreboot, devices. Signed-off-by: Thomas Zimmermann <[email protected]> --- drivers/video/aperture.c | 60 ++++++++++++++++++++++++++++++++-------- include/linux/aperture.h | 16 +++++++++++ 2 files changed, 64 insertions(+), 12 deletions(-) diff --git a/drivers/video/aperture.c b/drivers/video/aperture.c index 2b5a1e666e9b..15e664a4478b 100644 --- a/drivers/video/aperture.c +++ b/drivers/video/aperture.c @@ -1,6 +1,7 @@ // SPDX-License-Identifier: MIT #include <linux/aperture.h> +#include <linux/coreboot.h> #include <linux/device.h> #include <linux/list.h> #include <linux/mutex.h> @@ -197,22 +198,47 @@ static int devm_aperture_acquire(struct device *dev, return devm_add_action_or_reset(dev, devm_aperture_acquire_release, ap); } +#if defined(CONFIG_GOOGLE_COREBOOT_TABLE) +static void aperture_detach_coreboot_device(struct device *dev) +{ + struct coreboot_device *cbdev = dev_to_coreboot_device(dev); + + device_unregister(&cbdev->dev); +} + +/** + * devm_aperture_acquire_for_coreboot_device - Acquires ownership of an aperture + * on behalf of a coreboot device. + * @cbdev: the coreboot 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 coreboot device. If another + * driver takes over ownership of the aperture, aperture helpers will then + * unregister the coreboot 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_coreboot_device(struct coreboot_device *cbdev, + resource_size_t base, + resource_size_t size) +{ + return devm_aperture_acquire(&cbdev->dev, base, size, aperture_detach_coreboot_device); +} +EXPORT_SYMBOL(devm_aperture_acquire_for_coreboot_device); +#endif + 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 fb 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); } @@ -264,6 +290,16 @@ static void aperture_detach_devices(resource_size_t base, resource_size_t size) ap->dev = NULL; /* detach from device */ list_del(&ap->lh); + /* + * Remove the device from the device hierarchy. This is the right thing + * to do for firmware-based fb drivers, such as EFI, VESA or VGA. After + * the new driver takes over the hardware, the firmware device's state + * will be lost. + * + * 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. + */ ap->detach(dev); } diff --git a/include/linux/aperture.h b/include/linux/aperture.h index 1a9a88b11584..459823f86dc8 100644 --- a/include/linux/aperture.h +++ b/include/linux/aperture.h @@ -5,10 +5,17 @@ #include <linux/types.h> +struct coreboot_device; struct pci_dev; struct platform_device; #if defined(CONFIG_APERTURE_HELPERS) +#if defined(CONFIG_GOOGLE_COREBOOT_TABLE) +int devm_aperture_acquire_for_coreboot_device(struct coreboot_device *cbdev, + resource_size_t base, + resource_size_t size); +#endif + int devm_aperture_acquire_for_platform_device(struct platform_device *pdev, resource_size_t base, resource_size_t size); @@ -20,6 +27,15 @@ int __aperture_remove_legacy_vga_devices(struct pci_dev *pdev); int aperture_remove_conflicting_pci_devices(struct pci_dev *pdev, const char *name); #else +#if defined(CONFIG_GOOGLE_COREBOOT_TABLE) +static inline int devm_aperture_acquire_for_coreboot_device(struct coreboot_device *cbdev, + resource_size_t base, + resource_size_t size) +{ + return 0; +} +#endif + static inline int devm_aperture_acquire_for_platform_device(struct platform_device *pdev, resource_size_t base, resource_size_t size) -- 2.52.0
