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Message-ID: <8da62fff-5402-db70-eae5-9174e6753fc7@loongson.cn>
Date:   Tue, 27 Jun 2023 22:21:13 +0800
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Subject: Re: [PATCH v7 5/8] video/aperture: Add a helper to detect if an
 aperture contains firmware FB
Content-Language: en-US
To:     Sui Jingfeng <15330273260@189.cn>,
        Bjorn Helgaas <bhelgaas@google.com>
Cc:     amd-gfx@lists.freedesktop.org, dri-devel@lists.freedesktop.org,
        linux-kernel@vger.kernel.org, intel-gfx@lists.freedesktop.org,
        nouveau@lists.freedesktop.org, linux-pci@vger.kernel.org,
        kvm@vger.kernel.org, linux-fbdev@vger.kernel.org,
        Thomas Zimmermann <tzimmermann@suse.de>,
        Javier Martinez Canillas <javierm@redhat.com>,
        Maarten Lankhorst <maarten.lankhorst@linux.intel.com>,
        Maxime Ripard <mripard@kernel.org>,
        David Airlie <airlied@gmail.com>,
        Daniel Vetter <daniel@ffwll.ch>, Helge Deller <deller@gmx.de>,
        Jani Nikula <jani.nikula@linux.intel.com>
References: <20230613030151.216625-1-15330273260@189.cn>
 <20230613030151.216625-6-15330273260@189.cn>
From:   Sui Jingfeng <suijingfeng@loongson.cn>
Organization: Loongson
In-Reply-To: <20230613030151.216625-6-15330273260@189.cn>
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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