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    SubjectRe: [PATCH v7 5/8] video/aperture: Add a helper to detect if an aperture contains firmware FB
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      PING ?

    On 2023/6/13 11:01, Sui Jingfeng wrote:
    > From: Sui Jingfeng <suijingfeng@loongson.cn>
    >
    > This patch adds the aperture_contain_firmware_fb() function to do the
    > determination. Unfortunately due to the fact that apertures list will be
    > freed dynamically, the location and size information of the firmware fb
    > will be lost after dedicated drivers call
    > aperture_remove_conflicting_devices(),
    > aperture_remove_conflicting_pci_devices() or
    > aperture_remove_all_conflicting_devices() functions
    >
    > We handle this problem by introducing two static variables which record the
    > firmware framebuffer's start addrness and end addrness. It assumes that the
    > system has only one active firmware framebuffer driver at a time.
    >
    > We don't use the global structure screen_info here, because PCI resource
    > may get reallocated(the VRAM BAR could be moved) at kernel boot stage.
    >
    > Cc: Thomas Zimmermann <tzimmermann@suse.de>
    > Cc: Javier Martinez Canillas <javierm@redhat.com>
    > Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
    > Cc: Maxime Ripard <mripard@kernel.org>
    > Cc: David Airlie <airlied@gmail.com>
    > Cc: Daniel Vetter <daniel@ffwll.ch>
    > Cc: Helge Deller <deller@gmx.de>
    > Signed-off-by: Sui Jingfeng <suijingfeng@loongson.cn>
    > ---
    > drivers/gpu/drm/drm_aperture.c | 16 ++++++++++++++++
    > drivers/video/aperture.c | 29 +++++++++++++++++++++++++++++
    > include/drm/drm_aperture.h | 2 ++
    > include/linux/aperture.h | 7 +++++++
    > 4 files changed, 54 insertions(+)
    >
    > diff --git a/drivers/gpu/drm/drm_aperture.c b/drivers/gpu/drm/drm_aperture.c
    > index 5729f3bb4398..6e5d8a08683c 100644
    > --- a/drivers/gpu/drm/drm_aperture.c
    > +++ b/drivers/gpu/drm/drm_aperture.c
    > @@ -190,3 +190,19 @@ int drm_aperture_remove_conflicting_pci_framebuffers(struct pci_dev *pdev,
    > return aperture_remove_conflicting_pci_devices(pdev, req_driver->name);
    > }
    > EXPORT_SYMBOL(drm_aperture_remove_conflicting_pci_framebuffers);
    > +
    > +/**
    > + * drm_aperture_contain_firmware_fb - Determine if a aperture contains firmware framebuffer
    > + *
    > + * @base: the aperture's base address in physical memory
    > + * @size: aperture size in bytes
    > + *
    > + * Returns:
    > + * true on if there is a firmware framebuffer belong to the aperture passed in,
    > + * or false otherwise.
    > + */
    > +bool drm_aperture_contain_firmware_fb(resource_size_t base, resource_size_t size)
    > +{
    > + return aperture_contain_firmware_fb(base, base + size);
    > +}
    > +EXPORT_SYMBOL(drm_aperture_contain_firmware_fb);
    > diff --git a/drivers/video/aperture.c b/drivers/video/aperture.c
    > index 561be8feca96..5a5422cec669 100644
    > --- a/drivers/video/aperture.c
    > +++ b/drivers/video/aperture.c
    > @@ -141,6 +141,9 @@ struct aperture_range {
    > static LIST_HEAD(apertures);
    > static DEFINE_MUTEX(apertures_lock);
    >
    > +static resource_size_t firm_fb_start;
    > +static resource_size_t firm_fb_end;
    > +
    > static bool overlap(resource_size_t base1, resource_size_t end1,
    > resource_size_t base2, resource_size_t end2)
    > {
    > @@ -170,6 +173,9 @@ static int devm_aperture_acquire(struct device *dev,
    >
    > mutex_lock(&apertures_lock);
    >
    > + firm_fb_start = base;
    > + firm_fb_end = end;
    > +
    > list_for_each(pos, &apertures) {
    > ap = container_of(pos, struct aperture_range, lh);
    > if (overlap(base, end, ap->base, ap->base + ap->size)) {
    > @@ -377,3 +383,26 @@ int aperture_remove_conflicting_pci_devices(struct pci_dev *pdev, const char *na
    >
    > }
    > EXPORT_SYMBOL(aperture_remove_conflicting_pci_devices);
    > +
    > +/**
    > + * aperture_contain_firmware_fb - Detect if the firmware framebuffer belong to
    > + * a aperture.
    > + * @ap_start: the aperture's start address in physical memory
    > + * @ap_end: the aperture's end address in physical memory
    > + *
    > + * Returns:
    > + * true on if there is a firmware framebuffer belong to the aperture passed in,
    > + * or false otherwise.
    > + */
    > +bool aperture_contain_firmware_fb(resource_size_t ap_start, resource_size_t ap_end)
    > +{
    > + /* No firmware framebuffer support */
    > + if (!firm_fb_start || !firm_fb_end)
    > + return false;
    > +
    > + if (firm_fb_start >= ap_start && firm_fb_end <= ap_end)
    > + return true;
    > +
    > + return false;
    > +}
    > +EXPORT_SYMBOL(aperture_contain_firmware_fb);
    > diff --git a/include/drm/drm_aperture.h b/include/drm/drm_aperture.h
    > index cbe33b49fd5d..6a0b9bacb081 100644
    > --- a/include/drm/drm_aperture.h
    > +++ b/include/drm/drm_aperture.h
    > @@ -35,4 +35,6 @@ drm_aperture_remove_framebuffers(const struct drm_driver *req_driver)
    > req_driver);
    > }
    >
    > +bool drm_aperture_contain_firmware_fb(resource_size_t base, resource_size_t size);
    > +
    > #endif
    > diff --git a/include/linux/aperture.h b/include/linux/aperture.h
    > index 1a9a88b11584..d4dc5917c49b 100644
    > --- a/include/linux/aperture.h
    > +++ b/include/linux/aperture.h
    > @@ -19,6 +19,8 @@ int aperture_remove_conflicting_devices(resource_size_t base, resource_size_t si
    > int __aperture_remove_legacy_vga_devices(struct pci_dev *pdev);
    >
    > int aperture_remove_conflicting_pci_devices(struct pci_dev *pdev, const char *name);
    > +
    > +bool aperture_contain_firmware_fb(resource_size_t ap_start, resource_size_t ap_end);
    > #else
    > static inline int devm_aperture_acquire_for_platform_device(struct platform_device *pdev,
    > resource_size_t base,
    > @@ -42,6 +44,11 @@ static inline int aperture_remove_conflicting_pci_devices(struct pci_dev *pdev,
    > {
    > return 0;
    > }
    > +
    > +static inline bool aperture_contain_firmware_fb(resource_size_t ap_start, resource_size_t ap_end)
    > +{
    > + return false;
    > +}
    > #endif
    >
    > /**

    --
    Jingfeng

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