[PATCH 0/5] sysfb: Fix memory-region management

[PATCH 0/5] sysfb: Fix memory-region management

[Thomas Zimmermann]

Request framebuffer memory in simpledrm and simplefb. Do a hot-unplug
operation when removing fbdev firmware drivers.

After being unloaded by a hardware driver, simplefb leaves behind the
firmware framebuffer's platform device. This prevents other drivers
from acquiring the memory as reported at [1].

Patch 1 changes the removal code of remove_conflicting_framebuffers()
to remove the underlying device and the rsp memory region.

Patches 2 to 4 update sysfb and its drivers. The sysfb code does no
longer mark the framebuffer memory with IORESOURCE_BUSY. Instead, the
device drivers acquire the memory when they probe the device.

Patch 5 adds a todo item to acquire memory regions in all DRM drivers.

Tested with simpledrm and simplefb.

[1] https://lore.kernel.org/dri-devel/20220117180359.18114-1-zack@kde.org/

v2:
	* fix possible NULL deref in simpledrm (Jocelyn)
	* various style fixes (Javier)

Javier Martinez Canillas (1):
  drivers/firmware: Don't mark as busy the simple-framebuffer IO
    resource

Thomas Zimmermann (4):
  fbdev: Hot-unplug firmware fb devices on forced removal
  drm/simpledrm: Request memory region in driver
  fbdev/simplefb: Request memory region in driver
  drm: Add TODO item for requesting memory regions

 Documentation/gpu/todo.rst        | 15 +++++++
 drivers/firmware/sysfb_simplefb.c |  2 +-
 drivers/gpu/drm/tiny/simpledrm.c  | 22 ++++++++---
 drivers/video/fbdev/core/fbmem.c  | 29 ++++++++++++--
 drivers/video/fbdev/simplefb.c    | 65 +++++++++++++++++++++----------
 include/linux/fb.h                |  1 +
 6 files changed, 105 insertions(+), 29 deletions(-)


base-commit: 0bb81b5d6db5f689b67f9d8b35323235c45e890f
prerequisite-patch-id: c2b2f08f0eccc9f5df0c0da49fa1d36267deb11d
prerequisite-patch-id: c67e5d886a47b7d0266d81100837557fda34cb24
prerequisite-patch-id: 8e52143a6cd7b8fb789e656208f6edde71d0f499
-- 
2.34.1

[PATCH 0/5] sysfb: Fix memory-region management

[Thomas Zimmermann]

Request framebuffer memory in simpledrm and simplefb. Do a hot-unplug
operation when removing fbdev firmware drivers.

After being unloaded by a hardware driver, simplefb leaves behind the
firmware framebuffer's platform device. This prevents other drivers
from acquiring the memory as reported at [1].

Patch 1 changes the removal code of remove_conflicting_framebuffers()
to remove the underlying device and the rsp memory region.

Patches 2 to 4 update sysfb and its drivers. The sysfb code does no
longer mark the framebuffer memory with IORESOURCE_BUSY. Instead, the
device drivers acquire the memory when they probe the device.

Patch 5 adds a todo item to acquire memory regions in all DRM drivers.

Tested with simpledrm and simplefb.

[1] https://lore.kernel.org/dri-devel/20220117180359.18114-1-zack@kde.org/

v2:
	* fix possible NULL deref in simpledrm (Jocelyn)
	* various style fixes (Javier)

Javier Martinez Canillas (1):
  drivers/firmware: Don't mark as busy the simple-framebuffer IO
    resource

Thomas Zimmermann (4):
  fbdev: Hot-unplug firmware fb devices on forced removal
  drm/simpledrm: Request memory region in driver
  fbdev/simplefb: Request memory region in driver
  drm: Add TODO item for requesting memory regions

 Documentation/gpu/todo.rst        | 15 +++++++
 drivers/firmware/sysfb_simplefb.c |  2 +-
 drivers/gpu/drm/tiny/simpledrm.c  | 22 ++++++++---
 drivers/video/fbdev/core/fbmem.c  | 29 ++++++++++++--
 drivers/video/fbdev/simplefb.c    | 65 +++++++++++++++++++++----------
 include/linux/fb.h                |  1 +
 6 files changed, 105 insertions(+), 29 deletions(-)


base-commit: 0bb81b5d6db5f689b67f9d8b35323235c45e890f
prerequisite-patch-id: c2b2f08f0eccc9f5df0c0da49fa1d36267deb11d
prerequisite-patch-id: c67e5d886a47b7d0266d81100837557fda34cb24
prerequisite-patch-id: 8e52143a6cd7b8fb789e656208f6edde71d0f499
-- 
2.34.1

[PATCH 1/5] fbdev: Hot-unplug firmware fb devices on forced removal

[Thomas Zimmermann]

Hot-unplug all firmware-framebuffer devices as part of removing
them via remove_conflicting_framebuffers() et al. Releases all
memory regions to be acquired by native drivers.

Firmware, such as EFI, install a framebuffer while posting the
computer. After removing the firmware-framebuffer device from fbdev,
a native driver takes over the hardware and the firmware framebuffer
becomes invalid.

Firmware-framebuffer drivers, specifically simplefb, don't release
their device from Linux' device hierarchy. It still owns the firmware
framebuffer and blocks the native drivers from loading. This has been
observed in the vmwgfx driver. [1]

Initiating a device removal (i.e., hot unplug) as part of
remove_conflicting_framebuffers() removes the underlying device and
returns the memory range to the system.

[1] https://lore.kernel.org/dri-devel/20220117180359.18114-1-zack@kde.org/

v2:
	* rename variable 'dev' to 'device' (Javier)

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Reported-by: Zack Rusin <zackr@vmware.com>
Reviewed-by: Javier Martinez Canillas <javierm@redhat.com>
Reviewed-by: Zack Rusin <zackr@vmware.com>
CC: stable@vger.kernel.org # v5.11+
---
 drivers/video/fbdev/core/fbmem.c | 29 ++++++++++++++++++++++++++---
 include/linux/fb.h               |  1 +
 2 files changed, 27 insertions(+), 3 deletions(-)

diff --git a/drivers/video/fbdev/core/fbmem.c b/drivers/video/fbdev/core/fbmem.c
index 0fa7ede94fa6..b585339509b0 100644
--- a/drivers/video/fbdev/core/fbmem.c
+++ b/drivers/video/fbdev/core/fbmem.c
@@ -25,6 +25,7 @@
 #include <linux/init.h>
 #include <linux/linux_logo.h>
 #include <linux/proc_fs.h>
+#include <linux/platform_device.h>
 #include <linux/seq_file.h>
 #include <linux/console.h>
 #include <linux/kmod.h>
@@ -1557,18 +1558,36 @@ static void do_remove_conflicting_framebuffers(struct apertures_struct *a,
 	/* check all firmware fbs and kick off if the base addr overlaps */
 	for_each_registered_fb(i) {
 		struct apertures_struct *gen_aper;
+		struct device *device;
 
 		if (!(registered_fb[i]->flags & FBINFO_MISC_FIRMWARE))
 			continue;
 
 		gen_aper = registered_fb[i]->apertures;
+		device = registered_fb[i]->device;
 		if (fb_do_apertures_overlap(gen_aper, a) ||
 			(primary && gen_aper && gen_aper->count &&
 			 gen_aper->ranges[0].base == VGA_FB_PHYS)) {
 
 			printk(KERN_INFO "fb%d: switching to %s from %s\n",
 			       i, name, registered_fb[i]->fix.id);
-			do_unregister_framebuffer(registered_fb[i]);
+
+			/*
+			 * If we kick-out a firmware driver, we also want to remove
+			 * the underlying platform device, such as simple-framebuffer,
+			 * VESA, EFI, etc. A native driver will then be able to
+			 * allocate the memory range.
+			 *
+			 * If it's not a platform device, at least print a warning. A
+			 * fix would add code to remove the device from the system.
+			 */
+			if (dev_is_platform(device)) {
+				registered_fb[i]->forced_out = true;
+				platform_device_unregister(to_platform_device(device));
+			} else {
+				pr_warn("fb%d: cannot remove device\n", i);
+				do_unregister_framebuffer(registered_fb[i]);
+			}
 		}
 	}
 }
@@ -1898,9 +1917,13 @@ EXPORT_SYMBOL(register_framebuffer);
 void
 unregister_framebuffer(struct fb_info *fb_info)
 {
-	mutex_lock(&registration_lock);
+	bool forced_out = fb_info->forced_out;
+
+	if (!forced_out)
+		mutex_lock(&registration_lock);
 	do_unregister_framebuffer(fb_info);
-	mutex_unlock(&registration_lock);
+	if (!forced_out)
+		mutex_unlock(&registration_lock);
 }
 EXPORT_SYMBOL(unregister_framebuffer);
 
diff --git a/include/linux/fb.h b/include/linux/fb.h
index 3da95842b207..9a14f3f8a329 100644
--- a/include/linux/fb.h
+++ b/include/linux/fb.h
@@ -502,6 +502,7 @@ struct fb_info {
 	} *apertures;
 
 	bool skip_vt_switch; /* no VT switch on suspend/resume required */
+	bool forced_out; /* set when being removed by another driver */
 };
 
 static inline struct apertures_struct *alloc_apertures(unsigned int max_num) {
-- 
2.34.1

[PATCH 1/5] fbdev: Hot-unplug firmware fb devices on forced removal

[Thomas Zimmermann]

Hot-unplug all firmware-framebuffer devices as part of removing
them via remove_conflicting_framebuffers() et al. Releases all
memory regions to be acquired by native drivers.

Firmware, such as EFI, install a framebuffer while posting the
computer. After removing the firmware-framebuffer device from fbdev,
a native driver takes over the hardware and the firmware framebuffer
becomes invalid.

Firmware-framebuffer drivers, specifically simplefb, don't release
their device from Linux' device hierarchy. It still owns the firmware
framebuffer and blocks the native drivers from loading. This has been
observed in the vmwgfx driver. [1]

Initiating a device removal (i.e., hot unplug) as part of
remove_conflicting_framebuffers() removes the underlying device and
returns the memory range to the system.

[1] https://lore.kernel.org/dri-devel/20220117180359.18114-1-zack@kde.org/

v2:
	* rename variable 'dev' to 'device' (Javier)

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Reported-by: Zack Rusin <zackr@vmware.com>
Reviewed-by: Javier Martinez Canillas <javierm@redhat.com>
Reviewed-by: Zack Rusin <zackr@vmware.com>
CC: stable@vger.kernel.org # v5.11+
---
 drivers/video/fbdev/core/fbmem.c | 29 ++++++++++++++++++++++++++---
 include/linux/fb.h               |  1 +
 2 files changed, 27 insertions(+), 3 deletions(-)

diff --git a/drivers/video/fbdev/core/fbmem.c b/drivers/video/fbdev/core/fbmem.c
index 0fa7ede94fa6..b585339509b0 100644
--- a/drivers/video/fbdev/core/fbmem.c
+++ b/drivers/video/fbdev/core/fbmem.c
@@ -25,6 +25,7 @@
 #include <linux/init.h>
 #include <linux/linux_logo.h>
 #include <linux/proc_fs.h>
+#include <linux/platform_device.h>
 #include <linux/seq_file.h>
 #include <linux/console.h>
 #include <linux/kmod.h>
@@ -1557,18 +1558,36 @@ static void do_remove_conflicting_framebuffers(struct apertures_struct *a,
 	/* check all firmware fbs and kick off if the base addr overlaps */
 	for_each_registered_fb(i) {
 		struct apertures_struct *gen_aper;
+		struct device *device;
 
 		if (!(registered_fb[i]->flags & FBINFO_MISC_FIRMWARE))
 			continue;
 
 		gen_aper = registered_fb[i]->apertures;
+		device = registered_fb[i]->device;
 		if (fb_do_apertures_overlap(gen_aper, a) ||
 			(primary && gen_aper && gen_aper->count &&
 			 gen_aper->ranges[0].base == VGA_FB_PHYS)) {
 
 			printk(KERN_INFO "fb%d: switching to %s from %s\n",
 			       i, name, registered_fb[i]->fix.id);
-			do_unregister_framebuffer(registered_fb[i]);
+
+			/*
+			 * If we kick-out a firmware driver, we also want to remove
+			 * the underlying platform device, such as simple-framebuffer,
+			 * VESA, EFI, etc. A native driver will then be able to
+			 * allocate the memory range.
+			 *
+			 * If it's not a platform device, at least print a warning. A
+			 * fix would add code to remove the device from the system.
+			 */
+			if (dev_is_platform(device)) {
+				registered_fb[i]->forced_out = true;
+				platform_device_unregister(to_platform_device(device));
+			} else {
+				pr_warn("fb%d: cannot remove device\n", i);
+				do_unregister_framebuffer(registered_fb[i]);
+			}
 		}
 	}
 }
@@ -1898,9 +1917,13 @@ EXPORT_SYMBOL(register_framebuffer);
 void
 unregister_framebuffer(struct fb_info *fb_info)
 {
-	mutex_lock(&registration_lock);
+	bool forced_out = fb_info->forced_out;
+
+	if (!forced_out)
+		mutex_lock(&registration_lock);
 	do_unregister_framebuffer(fb_info);
-	mutex_unlock(&registration_lock);
+	if (!forced_out)
+		mutex_unlock(&registration_lock);
 }
 EXPORT_SYMBOL(unregister_framebuffer);
 
diff --git a/include/linux/fb.h b/include/linux/fb.h
index 3da95842b207..9a14f3f8a329 100644
--- a/include/linux/fb.h
+++ b/include/linux/fb.h
@@ -502,6 +502,7 @@ struct fb_info {
 	} *apertures;
 
 	bool skip_vt_switch; /* no VT switch on suspend/resume required */
+	bool forced_out; /* set when being removed by another driver */
 };
 
 static inline struct apertures_struct *alloc_apertures(unsigned int max_num) {
-- 
2.34.1

[PATCH 2/5] drivers/firmware: Don't mark as busy the simple-framebuffer IO resource

[Thomas Zimmermann]

From: Javier Martinez Canillas <javierm@redhat.com>

The sysfb_create_simplefb() function requests a IO memory resource for the
simple-framebuffer platform device, but it also marks it as busy which can
lead to drivers requesting the same memory resource to fail.

Let's drop the IORESOURCE_BUSY flag and let drivers to request it as busy
instead.

Signed-off-by: Javier Martinez Canillas <javierm@redhat.com>
Reviewed-by: Zack Rusin <zackr@vmware.com>
Reviewed-by: Thomas Zimmermann <tzimmermann@suse.de>
---
 drivers/firmware/sysfb_simplefb.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/firmware/sysfb_simplefb.c b/drivers/firmware/sysfb_simplefb.c
index 303a491e520d..76c4abc42a30 100644
--- a/drivers/firmware/sysfb_simplefb.c
+++ b/drivers/firmware/sysfb_simplefb.c
@@ -99,7 +99,7 @@ __init int sysfb_create_simplefb(const struct screen_info *si,
 
 	/* setup IORESOURCE_MEM as framebuffer memory */
 	memset(&res, 0, sizeof(res));
-	res.flags = IORESOURCE_MEM | IORESOURCE_BUSY;
+	res.flags = IORESOURCE_MEM;
 	res.name = simplefb_resname;
 	res.start = base;
 	res.end = res.start + length - 1;
-- 
2.34.1

[PATCH 2/5] drivers/firmware: Don't mark as busy the simple-framebuffer IO resource

[Thomas Zimmermann]

From: Javier Martinez Canillas <javierm@redhat.com>

The sysfb_create_simplefb() function requests a IO memory resource for the
simple-framebuffer platform device, but it also marks it as busy which can
lead to drivers requesting the same memory resource to fail.

Let's drop the IORESOURCE_BUSY flag and let drivers to request it as busy
instead.

Signed-off-by: Javier Martinez Canillas <javierm@redhat.com>
Reviewed-by: Zack Rusin <zackr@vmware.com>
Reviewed-by: Thomas Zimmermann <tzimmermann@suse.de>
---
 drivers/firmware/sysfb_simplefb.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/firmware/sysfb_simplefb.c b/drivers/firmware/sysfb_simplefb.c
index 303a491e520d..76c4abc42a30 100644
--- a/drivers/firmware/sysfb_simplefb.c
+++ b/drivers/firmware/sysfb_simplefb.c
@@ -99,7 +99,7 @@ __init int sysfb_create_simplefb(const struct screen_info *si,
 
 	/* setup IORESOURCE_MEM as framebuffer memory */
 	memset(&res, 0, sizeof(res));
-	res.flags = IORESOURCE_MEM | IORESOURCE_BUSY;
+	res.flags = IORESOURCE_MEM;
 	res.name = simplefb_resname;
 	res.start = base;
 	res.end = res.start + length - 1;
-- 
2.34.1

[PATCH 3/5] drm/simpledrm: Request memory region in driver

[Thomas Zimmermann]

Requesting the framebuffer memory in simpledrm marks the memory
range as busy. This used to be done by the firmware sysfb code,
but the driver is the correct place.

v2:
	* use I/O memory if request_mem_region() fails (Jocelyn)

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Reviewed-by: Javier Martinez Canillas <javierm@redhat.com>
---
 drivers/gpu/drm/tiny/simpledrm.c | 22 +++++++++++++++++-----
 1 file changed, 17 insertions(+), 5 deletions(-)

diff --git a/drivers/gpu/drm/tiny/simpledrm.c b/drivers/gpu/drm/tiny/simpledrm.c
index 04146da2d1d8..d191e87a37b5 100644
--- a/drivers/gpu/drm/tiny/simpledrm.c
+++ b/drivers/gpu/drm/tiny/simpledrm.c
@@ -526,21 +526,33 @@ static int simpledrm_device_init_mm(struct simpledrm_device *sdev)
 {
 	struct drm_device *dev = &sdev->dev;
 	struct platform_device *pdev = sdev->pdev;
-	struct resource *mem;
+	struct resource *res, *mem;
 	void __iomem *screen_base;
 	int ret;
 
-	mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
-	if (!mem)
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	if (!res)
 		return -EINVAL;
 
-	ret = devm_aperture_acquire_from_firmware(dev, mem->start, resource_size(mem));
+	ret = devm_aperture_acquire_from_firmware(dev, res->start, resource_size(res));
 	if (ret) {
 		drm_err(dev, "could not acquire memory range %pr: error %d\n",
-			mem, ret);
+			res, ret);
 		return ret;
 	}
 
+	mem = devm_request_mem_region(&pdev->dev, res->start, resource_size(res),
+				      sdev->dev.driver->name);
+	if (!mem) {
+		/*
+		 * We cannot make this fatal. Sometimes this comes from magic
+		 * spaces our resource handlers simply don't know about. Use
+		 * the I/O-memory resource as-is and try to map that instead.
+		 */
+		drm_warn(dev, "could not acquire memory region %pr\n", res);
+		mem = res;
+	}
+
 	screen_base = devm_ioremap_wc(&pdev->dev, mem->start,
 				      resource_size(mem));
 	if (!screen_base)
-- 
2.34.1

[PATCH 3/5] drm/simpledrm: Request memory region in driver

[Thomas Zimmermann]

Requesting the framebuffer memory in simpledrm marks the memory
range as busy. This used to be done by the firmware sysfb code,
but the driver is the correct place.

v2:
	* use I/O memory if request_mem_region() fails (Jocelyn)

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Reviewed-by: Javier Martinez Canillas <javierm@redhat.com>
---
 drivers/gpu/drm/tiny/simpledrm.c | 22 +++++++++++++++++-----
 1 file changed, 17 insertions(+), 5 deletions(-)

diff --git a/drivers/gpu/drm/tiny/simpledrm.c b/drivers/gpu/drm/tiny/simpledrm.c
index 04146da2d1d8..d191e87a37b5 100644
--- a/drivers/gpu/drm/tiny/simpledrm.c
+++ b/drivers/gpu/drm/tiny/simpledrm.c
@@ -526,21 +526,33 @@ static int simpledrm_device_init_mm(struct simpledrm_device *sdev)
 {
 	struct drm_device *dev = &sdev->dev;
 	struct platform_device *pdev = sdev->pdev;
-	struct resource *mem;
+	struct resource *res, *mem;
 	void __iomem *screen_base;
 	int ret;
 
-	mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
-	if (!mem)
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	if (!res)
 		return -EINVAL;
 
-	ret = devm_aperture_acquire_from_firmware(dev, mem->start, resource_size(mem));
+	ret = devm_aperture_acquire_from_firmware(dev, res->start, resource_size(res));
 	if (ret) {
 		drm_err(dev, "could not acquire memory range %pr: error %d\n",
-			mem, ret);
+			res, ret);
 		return ret;
 	}
 
+	mem = devm_request_mem_region(&pdev->dev, res->start, resource_size(res),
+				      sdev->dev.driver->name);
+	if (!mem) {
+		/*
+		 * We cannot make this fatal. Sometimes this comes from magic
+		 * spaces our resource handlers simply don't know about. Use
+		 * the I/O-memory resource as-is and try to map that instead.
+		 */
+		drm_warn(dev, "could not acquire memory region %pr\n", res);
+		mem = res;
+	}
+
 	screen_base = devm_ioremap_wc(&pdev->dev, mem->start,
 				      resource_size(mem));
 	if (!screen_base)
-- 
2.34.1

[PATCH 4/5] fbdev/simplefb: Request memory region in driver

[Thomas Zimmermann]

Requesting the framebuffer memory in simpledrm marks the memory
range as busy. This used to be done by the firmware sysfb code,
but the driver is the correct place.

v2:
	* store memory region in struct for later cleanup (Javier)

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
---
 drivers/video/fbdev/simplefb.c | 65 +++++++++++++++++++++++-----------
 1 file changed, 45 insertions(+), 20 deletions(-)

diff --git a/drivers/video/fbdev/simplefb.c b/drivers/video/fbdev/simplefb.c
index 57541887188b..94fc9c6d0411 100644
--- a/drivers/video/fbdev/simplefb.c
+++ b/drivers/video/fbdev/simplefb.c
@@ -66,16 +66,36 @@ static int simplefb_setcolreg(u_int regno, u_int red, u_int green, u_int blue,
 	return 0;
 }
 
-struct simplefb_par;
+struct simplefb_par {
+	u32 palette[PSEUDO_PALETTE_SIZE];
+	struct resource *mem;
+#if defined CONFIG_OF && defined CONFIG_COMMON_CLK
+	bool clks_enabled;
+	unsigned int clk_count;
+	struct clk **clks;
+#endif
+#if defined CONFIG_OF && defined CONFIG_REGULATOR
+	bool regulators_enabled;
+	u32 regulator_count;
+	struct regulator **regulators;
+#endif
+};
+
 static void simplefb_clocks_destroy(struct simplefb_par *par);
 static void simplefb_regulators_destroy(struct simplefb_par *par);
 
 static void simplefb_destroy(struct fb_info *info)
 {
+	struct simplefb_par *par = info->par;
+	struct resource *mem = par->mem;
+
 	simplefb_regulators_destroy(info->par);
 	simplefb_clocks_destroy(info->par);
 	if (info->screen_base)
 		iounmap(info->screen_base);
+
+	if (mem)
+		release_mem_region(mem->start, resource_size(mem));
 }
 
 static const struct fb_ops simplefb_ops = {
@@ -169,20 +189,6 @@ static int simplefb_parse_pd(struct platform_device *pdev,
 	return 0;
 }
 
-struct simplefb_par {
-	u32 palette[PSEUDO_PALETTE_SIZE];
-#if defined CONFIG_OF && defined CONFIG_COMMON_CLK
-	bool clks_enabled;
-	unsigned int clk_count;
-	struct clk **clks;
-#endif
-#if defined CONFIG_OF && defined CONFIG_REGULATOR
-	bool regulators_enabled;
-	u32 regulator_count;
-	struct regulator **regulators;
-#endif
-};
-
 #if defined CONFIG_OF && defined CONFIG_COMMON_CLK
 /*
  * Clock handling code.
@@ -405,7 +411,7 @@ static int simplefb_probe(struct platform_device *pdev)
 	struct simplefb_params params;
 	struct fb_info *info;
 	struct simplefb_par *par;
-	struct resource *mem;
+	struct resource *res, *mem;
 
 	/*
 	 * Generic drivers must not be registered if a framebuffer exists.
@@ -430,15 +436,28 @@ static int simplefb_probe(struct platform_device *pdev)
 	if (ret)
 		return ret;
 
-	mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
-	if (!mem) {
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	if (!res) {
 		dev_err(&pdev->dev, "No memory resource\n");
 		return -EINVAL;
 	}
 
+	mem = request_mem_region(res->start, resource_size(res), "simplefb");
+	if (!mem) {
+		/*
+		 * We cannot make this fatal. Sometimes this comes from magic
+		 * spaces our resource handlers simply don't know about. Use
+		 * the I/O-memory resource as-is and try to map that instead.
+		 */
+		dev_warn(&pdev->dev, "simplefb: cannot reserve video memory at %pR\n", res);
+		mem = res;
+	}
+
 	info = framebuffer_alloc(sizeof(struct simplefb_par), &pdev->dev);
-	if (!info)
-		return -ENOMEM;
+	if (!info) {
+		ret = -ENOMEM;
+		goto error_release_mem_region;
+	}
 	platform_set_drvdata(pdev, info);
 
 	par = info->par;
@@ -495,6 +514,9 @@ static int simplefb_probe(struct platform_device *pdev)
 			     info->var.xres, info->var.yres,
 			     info->var.bits_per_pixel, info->fix.line_length);
 
+	if (mem != res)
+		par->mem = mem; /* release in clean-up handler */
+
 	ret = register_framebuffer(info);
 	if (ret < 0) {
 		dev_err(&pdev->dev, "Unable to register simplefb: %d\n", ret);
@@ -513,6 +535,9 @@ static int simplefb_probe(struct platform_device *pdev)
 	iounmap(info->screen_base);
 error_fb_release:
 	framebuffer_release(info);
+error_release_mem_region:
+	if (mem != res)
+		release_mem_region(mem->start, resource_size(mem));
 	return ret;
 }
 
-- 
2.34.1

[PATCH 4/5] fbdev/simplefb: Request memory region in driver

[Thomas Zimmermann]

Requesting the framebuffer memory in simpledrm marks the memory
range as busy. This used to be done by the firmware sysfb code,
but the driver is the correct place.

v2:
	* store memory region in struct for later cleanup (Javier)

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
---
 drivers/video/fbdev/simplefb.c | 65 +++++++++++++++++++++++-----------
 1 file changed, 45 insertions(+), 20 deletions(-)

diff --git a/drivers/video/fbdev/simplefb.c b/drivers/video/fbdev/simplefb.c
index 57541887188b..94fc9c6d0411 100644
--- a/drivers/video/fbdev/simplefb.c
+++ b/drivers/video/fbdev/simplefb.c
@@ -66,16 +66,36 @@ static int simplefb_setcolreg(u_int regno, u_int red, u_int green, u_int blue,
 	return 0;
 }
 
-struct simplefb_par;
+struct simplefb_par {
+	u32 palette[PSEUDO_PALETTE_SIZE];
+	struct resource *mem;
+#if defined CONFIG_OF && defined CONFIG_COMMON_CLK
+	bool clks_enabled;
+	unsigned int clk_count;
+	struct clk **clks;
+#endif
+#if defined CONFIG_OF && defined CONFIG_REGULATOR
+	bool regulators_enabled;
+	u32 regulator_count;
+	struct regulator **regulators;
+#endif
+};
+
 static void simplefb_clocks_destroy(struct simplefb_par *par);
 static void simplefb_regulators_destroy(struct simplefb_par *par);
 
 static void simplefb_destroy(struct fb_info *info)
 {
+	struct simplefb_par *par = info->par;
+	struct resource *mem = par->mem;
+
 	simplefb_regulators_destroy(info->par);
 	simplefb_clocks_destroy(info->par);
 	if (info->screen_base)
 		iounmap(info->screen_base);
+
+	if (mem)
+		release_mem_region(mem->start, resource_size(mem));
 }
 
 static const struct fb_ops simplefb_ops = {
@@ -169,20 +189,6 @@ static int simplefb_parse_pd(struct platform_device *pdev,
 	return 0;
 }
 
-struct simplefb_par {
-	u32 palette[PSEUDO_PALETTE_SIZE];
-#if defined CONFIG_OF && defined CONFIG_COMMON_CLK
-	bool clks_enabled;
-	unsigned int clk_count;
-	struct clk **clks;
-#endif
-#if defined CONFIG_OF && defined CONFIG_REGULATOR
-	bool regulators_enabled;
-	u32 regulator_count;
-	struct regulator **regulators;
-#endif
-};
-
 #if defined CONFIG_OF && defined CONFIG_COMMON_CLK
 /*
  * Clock handling code.
@@ -405,7 +411,7 @@ static int simplefb_probe(struct platform_device *pdev)
 	struct simplefb_params params;
 	struct fb_info *info;
 	struct simplefb_par *par;
-	struct resource *mem;
+	struct resource *res, *mem;
 
 	/*
 	 * Generic drivers must not be registered if a framebuffer exists.
@@ -430,15 +436,28 @@ static int simplefb_probe(struct platform_device *pdev)
 	if (ret)
 		return ret;
 
-	mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
-	if (!mem) {
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	if (!res) {
 		dev_err(&pdev->dev, "No memory resource\n");
 		return -EINVAL;
 	}
 
+	mem = request_mem_region(res->start, resource_size(res), "simplefb");
+	if (!mem) {
+		/*
+		 * We cannot make this fatal. Sometimes this comes from magic
+		 * spaces our resource handlers simply don't know about. Use
+		 * the I/O-memory resource as-is and try to map that instead.
+		 */
+		dev_warn(&pdev->dev, "simplefb: cannot reserve video memory at %pR\n", res);
+		mem = res;
+	}
+
 	info = framebuffer_alloc(sizeof(struct simplefb_par), &pdev->dev);
-	if (!info)
-		return -ENOMEM;
+	if (!info) {
+		ret = -ENOMEM;
+		goto error_release_mem_region;
+	}
 	platform_set_drvdata(pdev, info);
 
 	par = info->par;
@@ -495,6 +514,9 @@ static int simplefb_probe(struct platform_device *pdev)
 			     info->var.xres, info->var.yres,
 			     info->var.bits_per_pixel, info->fix.line_length);
 
+	if (mem != res)
+		par->mem = mem; /* release in clean-up handler */
+
 	ret = register_framebuffer(info);
 	if (ret < 0) {
 		dev_err(&pdev->dev, "Unable to register simplefb: %d\n", ret);
@@ -513,6 +535,9 @@ static int simplefb_probe(struct platform_device *pdev)
 	iounmap(info->screen_base);
 error_fb_release:
 	framebuffer_release(info);
+error_release_mem_region:
+	if (mem != res)
+		release_mem_region(mem->start, resource_size(mem));
 	return ret;
 }
 
-- 
2.34.1

[PATCH 5/5] drm: Add TODO item for requesting memory regions

[Thomas Zimmermann]

Add a TODO item about requesting  memory regions for each driver. The
current DRM drivers don't do this consistently.

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Reviewed-by: Javier Martinez Canillas <javierm@redhat.com>
---
 Documentation/gpu/todo.rst | 15 +++++++++++++++
 1 file changed, 15 insertions(+)

diff --git a/Documentation/gpu/todo.rst b/Documentation/gpu/todo.rst
index da138dd39883..1b2372ef4131 100644
--- a/Documentation/gpu/todo.rst
+++ b/Documentation/gpu/todo.rst
@@ -467,6 +467,21 @@ Contact: Thomas Zimmermann <tzimmermann@suse.de>
 
 Level: Intermediate
 
+Request memory regions in all drivers
+-------------------------------------
+
+Go through all drivers and add code to request the memory regions that the
+driver uses. This requires adding calls to request_mem_region(),
+pci_request_region() or similar functions. Use helpers for managed cleanup
+where possible.
+
+Drivers are pretty bad at doing this and there used to be conflicts among
+DRM and fbdev drivers. Still, it's the correct thing to do.
+
+Contact: Thomas Zimmermann <tzimmermann@suse.de>
+
+Level: Starter
+
 
 Core refactorings
 =================
-- 
2.34.1

[PATCH 5/5] drm: Add TODO item for requesting memory regions

[Thomas Zimmermann]

Add a TODO item about requesting  memory regions for each driver. The
current DRM drivers don't do this consistently.

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Reviewed-by: Javier Martinez Canillas <javierm@redhat.com>
---
 Documentation/gpu/todo.rst | 15 +++++++++++++++
 1 file changed, 15 insertions(+)

diff --git a/Documentation/gpu/todo.rst b/Documentation/gpu/todo.rst
index da138dd39883..1b2372ef4131 100644
--- a/Documentation/gpu/todo.rst
+++ b/Documentation/gpu/todo.rst
@@ -467,6 +467,21 @@ Contact: Thomas Zimmermann <tzimmermann@suse.de>
 
 Level: Intermediate
 
+Request memory regions in all drivers
+-------------------------------------
+
+Go through all drivers and add code to request the memory regions that the
+driver uses. This requires adding calls to request_mem_region(),
+pci_request_region() or similar functions. Use helpers for managed cleanup
+where possible.
+
+Drivers are pretty bad at doing this and there used to be conflicts among
+DRM and fbdev drivers. Still, it's the correct thing to do.
+
+Contact: Thomas Zimmermann <tzimmermann@suse.de>
+
+Level: Starter
+
 
 Core refactorings
 =================
-- 
2.34.1

Re: [PATCH 0/5] sysfb: Fix memory-region management

[Thomas Zimmermann]

[-- Attachment #1.1: Type: text/plain, Size: 2319 bytes --]

This v2 of the patchset. I forgot to adapt the subject line :/

Am 25.01.22 um 10:12 schrieb Thomas Zimmermann:
> Request framebuffer memory in simpledrm and simplefb. Do a hot-unplug
> operation when removing fbdev firmware drivers.
> 
> After being unloaded by a hardware driver, simplefb leaves behind the
> firmware framebuffer's platform device. This prevents other drivers
> from acquiring the memory as reported at [1].
> 
> Patch 1 changes the removal code of remove_conflicting_framebuffers()
> to remove the underlying device and the rsp memory region.
> 
> Patches 2 to 4 update sysfb and its drivers. The sysfb code does no
> longer mark the framebuffer memory with IORESOURCE_BUSY. Instead, the
> device drivers acquire the memory when they probe the device.
> 
> Patch 5 adds a todo item to acquire memory regions in all DRM drivers.
> 
> Tested with simpledrm and simplefb.
> 
> [1] https://lore.kernel.org/dri-devel/20220117180359.18114-1-zack@kde.org/
> 
> v2:
> 	* fix possible NULL deref in simpledrm (Jocelyn)
> 	* various style fixes (Javier)
> 
> Javier Martinez Canillas (1):
>    drivers/firmware: Don't mark as busy the simple-framebuffer IO
>      resource
> 
> Thomas Zimmermann (4):
>    fbdev: Hot-unplug firmware fb devices on forced removal
>    drm/simpledrm: Request memory region in driver
>    fbdev/simplefb: Request memory region in driver
>    drm: Add TODO item for requesting memory regions
> 
>   Documentation/gpu/todo.rst        | 15 +++++++
>   drivers/firmware/sysfb_simplefb.c |  2 +-
>   drivers/gpu/drm/tiny/simpledrm.c  | 22 ++++++++---
>   drivers/video/fbdev/core/fbmem.c  | 29 ++++++++++++--
>   drivers/video/fbdev/simplefb.c    | 65 +++++++++++++++++++++----------
>   include/linux/fb.h                |  1 +
>   6 files changed, 105 insertions(+), 29 deletions(-)
> 
> 
> base-commit: 0bb81b5d6db5f689b67f9d8b35323235c45e890f
> prerequisite-patch-id: c2b2f08f0eccc9f5df0c0da49fa1d36267deb11d
> prerequisite-patch-id: c67e5d886a47b7d0266d81100837557fda34cb24
> prerequisite-patch-id: 8e52143a6cd7b8fb789e656208f6edde71d0f499

-- 
Thomas Zimmermann
Graphics Driver Developer
SUSE Software Solutions Germany GmbH
Maxfeldstr. 5, 90409 Nürnberg, Germany
(HRB 36809, AG Nürnberg)
Geschäftsführer: Ivo Totev

[-- Attachment #2: OpenPGP digital signature --]
[-- Type: application/pgp-signature, Size: 840 bytes --]

Re: [PATCH 0/5] sysfb: Fix memory-region management

[Thomas Zimmermann]

[-- Attachment #1.1: Type: text/plain, Size: 2319 bytes --]

This v2 of the patchset. I forgot to adapt the subject line :/

Am 25.01.22 um 10:12 schrieb Thomas Zimmermann:
> Request framebuffer memory in simpledrm and simplefb. Do a hot-unplug
> operation when removing fbdev firmware drivers.
> 
> After being unloaded by a hardware driver, simplefb leaves behind the
> firmware framebuffer's platform device. This prevents other drivers
> from acquiring the memory as reported at [1].
> 
> Patch 1 changes the removal code of remove_conflicting_framebuffers()
> to remove the underlying device and the rsp memory region.
> 
> Patches 2 to 4 update sysfb and its drivers. The sysfb code does no
> longer mark the framebuffer memory with IORESOURCE_BUSY. Instead, the
> device drivers acquire the memory when they probe the device.
> 
> Patch 5 adds a todo item to acquire memory regions in all DRM drivers.
> 
> Tested with simpledrm and simplefb.
> 
> [1] https://lore.kernel.org/dri-devel/20220117180359.18114-1-zack@kde.org/
> 
> v2:
> 	* fix possible NULL deref in simpledrm (Jocelyn)
> 	* various style fixes (Javier)
> 
> Javier Martinez Canillas (1):
>    drivers/firmware: Don't mark as busy the simple-framebuffer IO
>      resource
> 
> Thomas Zimmermann (4):
>    fbdev: Hot-unplug firmware fb devices on forced removal
>    drm/simpledrm: Request memory region in driver
>    fbdev/simplefb: Request memory region in driver
>    drm: Add TODO item for requesting memory regions
> 
>   Documentation/gpu/todo.rst        | 15 +++++++
>   drivers/firmware/sysfb_simplefb.c |  2 +-
>   drivers/gpu/drm/tiny/simpledrm.c  | 22 ++++++++---
>   drivers/video/fbdev/core/fbmem.c  | 29 ++++++++++++--
>   drivers/video/fbdev/simplefb.c    | 65 +++++++++++++++++++++----------
>   include/linux/fb.h                |  1 +
>   6 files changed, 105 insertions(+), 29 deletions(-)
> 
> 
> base-commit: 0bb81b5d6db5f689b67f9d8b35323235c45e890f
> prerequisite-patch-id: c2b2f08f0eccc9f5df0c0da49fa1d36267deb11d
> prerequisite-patch-id: c67e5d886a47b7d0266d81100837557fda34cb24
> prerequisite-patch-id: 8e52143a6cd7b8fb789e656208f6edde71d0f499

-- 
Thomas Zimmermann
Graphics Driver Developer
SUSE Software Solutions Germany GmbH
Maxfeldstr. 5, 90409 Nürnberg, Germany
(HRB 36809, AG Nürnberg)
Geschäftsführer: Ivo Totev

[-- Attachment #2: OpenPGP digital signature --]
[-- Type: application/pgp-signature, Size: 840 bytes --]

Re: [PATCH 4/5] fbdev/simplefb: Request memory region in driver

[Javier Martinez Canillas]

Hello Thomas,

On 1/25/22 10:12, Thomas Zimmermann wrote:
> Requesting the framebuffer memory in simpledrm marks the memory
> range as busy. This used to be done by the firmware sysfb code,
> but the driver is the correct place.
> 
> v2:
> 	* store memory region in struct for later cleanup (Javier)
> 
> Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
> ---

Thanks a lot for updating the patch. Now this logic is also more
similar to the changes done for the simpledrm driver in PATCH 3/5.

Reviewed-by: Javier Martinez Canillas <javierm@redhat.com>

Best regards,
-- 
Javier Martinez Canillas
Linux Engineering
Red Hat

Re: [PATCH 4/5] fbdev/simplefb: Request memory region in driver

[Javier Martinez Canillas]

Hello Thomas,

On 1/25/22 10:12, Thomas Zimmermann wrote:
> Requesting the framebuffer memory in simpledrm marks the memory
> range as busy. This used to be done by the firmware sysfb code,
> but the driver is the correct place.
> 
> v2:
> 	* store memory region in struct for later cleanup (Javier)
> 
> Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
> ---

Thanks a lot for updating the patch. Now this logic is also more
similar to the changes done for the simpledrm driver in PATCH 3/5.

Reviewed-by: Javier Martinez Canillas <javierm@redhat.com>

Best regards,
-- 
Javier Martinez Canillas
Linux Engineering
Red Hat

Re: [PATCH 3/5] drm/simpledrm: Request memory region in driver

[Jocelyn Falempe]

Hi,

Thanks for the fix.

On 25/01/2022 10:12, Thomas Zimmermann wrote:
> Requesting the framebuffer memory in simpledrm marks the memory
> range as busy. This used to be done by the firmware sysfb code,
> but the driver is the correct place.
> 
> v2:
> 	* use I/O memory if request_mem_region() fails (Jocelyn)
> 
> Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
> Reviewed-by: Javier Martinez Canillas <javierm@redhat.com>

Reviewed-by: Jocelyn Falempe <jfalempe@redhat.com>

-- 

Jocelyn Falempe

Re: [PATCH 3/5] drm/simpledrm: Request memory region in driver

[Jocelyn Falempe]

Hi,

Thanks for the fix.

On 25/01/2022 10:12, Thomas Zimmermann wrote:
> Requesting the framebuffer memory in simpledrm marks the memory
> range as busy. This used to be done by the firmware sysfb code,
> but the driver is the correct place.
> 
> v2:
> 	* use I/O memory if request_mem_region() fails (Jocelyn)
> 
> Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
> Reviewed-by: Javier Martinez Canillas <javierm@redhat.com>

Reviewed-by: Jocelyn Falempe <jfalempe@redhat.com>

-- 

Jocelyn Falempe

Re: [PATCH 0/5] sysfb: Fix memory-region management

[Hans de Goede]

Hi Thomas,

On 1/25/22 10:12, Thomas Zimmermann wrote:
> Request framebuffer memory in simpledrm and simplefb. Do a hot-unplug
> operation when removing fbdev firmware drivers.
> 
> After being unloaded by a hardware driver, simplefb leaves behind the
> firmware framebuffer's platform device. This prevents other drivers
> from acquiring the memory as reported at [1].
> 
> Patch 1 changes the removal code of remove_conflicting_framebuffers()
> to remove the underlying device and the rsp memory region.
> 
> Patches 2 to 4 update sysfb and its drivers. The sysfb code does no
> longer mark the framebuffer memory with IORESOURCE_BUSY. Instead, the
> device drivers acquire the memory when they probe the device.
> 
> Patch 5 adds a todo item to acquire memory regions in all DRM drivers.
> 
> Tested with simpledrm and simplefb.
> 
> [1] https://lore.kernel.org/dri-devel/20220117180359.18114-1-zack@kde.org/
> 
> v2:
> 	* fix possible NULL deref in simpledrm (Jocelyn)
> 	* various style fixes (Javier)


The entire series looks good to me:

Reviewed-by: Hans de Goede <hdegoede@redhat.com>

for the series.

Regards,

Hans


> 
> Javier Martinez Canillas (1):
>   drivers/firmware: Don't mark as busy the simple-framebuffer IO
>     resource
> 
> Thomas Zimmermann (4):
>   fbdev: Hot-unplug firmware fb devices on forced removal
>   drm/simpledrm: Request memory region in driver
>   fbdev/simplefb: Request memory region in driver
>   drm: Add TODO item for requesting memory regions
> 
>  Documentation/gpu/todo.rst        | 15 +++++++
>  drivers/firmware/sysfb_simplefb.c |  2 +-
>  drivers/gpu/drm/tiny/simpledrm.c  | 22 ++++++++---
>  drivers/video/fbdev/core/fbmem.c  | 29 ++++++++++++--
>  drivers/video/fbdev/simplefb.c    | 65 +++++++++++++++++++++----------
>  include/linux/fb.h                |  1 +
>  6 files changed, 105 insertions(+), 29 deletions(-)
> 
> 
> base-commit: 0bb81b5d6db5f689b67f9d8b35323235c45e890f
> prerequisite-patch-id: c2b2f08f0eccc9f5df0c0da49fa1d36267deb11d
> prerequisite-patch-id: c67e5d886a47b7d0266d81100837557fda34cb24
> prerequisite-patch-id: 8e52143a6cd7b8fb789e656208f6edde71d0f499
> 

Re: [PATCH 0/5] sysfb: Fix memory-region management

[Hans de Goede]

Hi Thomas,

On 1/25/22 10:12, Thomas Zimmermann wrote:
> Request framebuffer memory in simpledrm and simplefb. Do a hot-unplug
> operation when removing fbdev firmware drivers.
> 
> After being unloaded by a hardware driver, simplefb leaves behind the
> firmware framebuffer's platform device. This prevents other drivers
> from acquiring the memory as reported at [1].
> 
> Patch 1 changes the removal code of remove_conflicting_framebuffers()
> to remove the underlying device and the rsp memory region.
> 
> Patches 2 to 4 update sysfb and its drivers. The sysfb code does no
> longer mark the framebuffer memory with IORESOURCE_BUSY. Instead, the
> device drivers acquire the memory when they probe the device.
> 
> Patch 5 adds a todo item to acquire memory regions in all DRM drivers.
> 
> Tested with simpledrm and simplefb.
> 
> [1] https://lore.kernel.org/dri-devel/20220117180359.18114-1-zack@kde.org/
> 
> v2:
> 	* fix possible NULL deref in simpledrm (Jocelyn)
> 	* various style fixes (Javier)


The entire series looks good to me:

Reviewed-by: Hans de Goede <hdegoede@redhat.com>

for the series.

Regards,

Hans


> 
> Javier Martinez Canillas (1):
>   drivers/firmware: Don't mark as busy the simple-framebuffer IO
>     resource
> 
> Thomas Zimmermann (4):
>   fbdev: Hot-unplug firmware fb devices on forced removal
>   drm/simpledrm: Request memory region in driver
>   fbdev/simplefb: Request memory region in driver
>   drm: Add TODO item for requesting memory regions
> 
>  Documentation/gpu/todo.rst        | 15 +++++++
>  drivers/firmware/sysfb_simplefb.c |  2 +-
>  drivers/gpu/drm/tiny/simpledrm.c  | 22 ++++++++---
>  drivers/video/fbdev/core/fbmem.c  | 29 ++++++++++++--
>  drivers/video/fbdev/simplefb.c    | 65 +++++++++++++++++++++----------
>  include/linux/fb.h                |  1 +
>  6 files changed, 105 insertions(+), 29 deletions(-)
> 
> 
> base-commit: 0bb81b5d6db5f689b67f9d8b35323235c45e890f
> prerequisite-patch-id: c2b2f08f0eccc9f5df0c0da49fa1d36267deb11d
> prerequisite-patch-id: c67e5d886a47b7d0266d81100837557fda34cb24
> prerequisite-patch-id: 8e52143a6cd7b8fb789e656208f6edde71d0f499
> 

Re: [PATCH 4/5] fbdev/simplefb: Request memory region in driver

[Javier Martinez Canillas]

On 1/24/22 13:36, Thomas Zimmermann wrote:
> Requesting the framebuffer memory in simpledrm marks the memory
> range as busy. This used to be done by the firmware sysfb code,
> but the driver is the correct place.
> 
> Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
> ---
>  drivers/video/fbdev/simplefb.c | 59 ++++++++++++++++++++++++----------
>  1 file changed, 42 insertions(+), 17 deletions(-)
> 
> diff --git a/drivers/video/fbdev/simplefb.c b/drivers/video/fbdev/simplefb.c
> index 57541887188b..84452028ecc9 100644
> --- a/drivers/video/fbdev/simplefb.c
> +++ b/drivers/video/fbdev/simplefb.c
> @@ -66,16 +66,36 @@ static int simplefb_setcolreg(u_int regno, u_int red, u_int green, u_int blue,
>  	return 0;
>  }
>  
> -struct simplefb_par;
> +struct simplefb_par {
> +	u32 palette[PSEUDO_PALETTE_SIZE];
> +#if defined CONFIG_OF && defined CONFIG_COMMON_CLK
> +	bool clks_enabled;
> +	unsigned int clk_count;
> +	struct clk **clks;
> +#endif
> +#if defined CONFIG_OF && defined CONFIG_REGULATOR
> +	bool regulators_enabled;
> +	u32 regulator_count;
> +	struct regulator **regulators;
> +#endif
> +	bool release_mem_region;

Maybe instead you could have:

	struct resource *mem; 

that would be more consistent with the fields for the other
resources like clocks, regulators, etc.

> +};
> +
>  static void simplefb_clocks_destroy(struct simplefb_par *par);
>  static void simplefb_regulators_destroy(struct simplefb_par *par);
>  
>  static void simplefb_destroy(struct fb_info *info)
>  {
> +	struct simplefb_par *par = info->par;
> +
>  	simplefb_regulators_destroy(info->par);
>  	simplefb_clocks_destroy(info->par);
>  	if (info->screen_base)
>  		iounmap(info->screen_base);
> +
> +	if (par->release_mem_region)
> +		release_mem_region(info->apertures->ranges[0].base,
> +				   info->apertures->ranges[0].size);

and here you could instead use the pointer to the resource:

	if (par->mem)
		release_mem_region(par->mem->start, resource_size(par->mem));

[snip]

>  static int simplefb_probe(struct platform_device *pdev)
>  {
> +	bool request_mem_succeeded = false;
>  	int ret;
>  	struct simplefb_params params;
>  	struct fb_info *info;
> @@ -436,9 +443,22 @@ static int simplefb_probe(struct platform_device *pdev)
>  		return -EINVAL;
>  	}
>  
> +	if (request_mem_region(mem->start, resource_size(mem), "simplefb")) {
> +		request_mem_succeeded = true;

and if you do the request_mem_region() after the struct fb_info allocation then
this could just be:

		par->mem = mem;

Best regards,
-- 
Javier Martinez Canillas
Linux Engineering
Red Hat

Re: [PATCH 4/5] fbdev/simplefb: Request memory region in driver

[Javier Martinez Canillas]

On 1/24/22 13:36, Thomas Zimmermann wrote:
> Requesting the framebuffer memory in simpledrm marks the memory
> range as busy. This used to be done by the firmware sysfb code,
> but the driver is the correct place.
> 
> Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
> ---
>  drivers/video/fbdev/simplefb.c | 59 ++++++++++++++++++++++++----------
>  1 file changed, 42 insertions(+), 17 deletions(-)
> 
> diff --git a/drivers/video/fbdev/simplefb.c b/drivers/video/fbdev/simplefb.c
> index 57541887188b..84452028ecc9 100644
> --- a/drivers/video/fbdev/simplefb.c
> +++ b/drivers/video/fbdev/simplefb.c
> @@ -66,16 +66,36 @@ static int simplefb_setcolreg(u_int regno, u_int red, u_int green, u_int blue,
>  	return 0;
>  }
>  
> -struct simplefb_par;
> +struct simplefb_par {
> +	u32 palette[PSEUDO_PALETTE_SIZE];
> +#if defined CONFIG_OF && defined CONFIG_COMMON_CLK
> +	bool clks_enabled;
> +	unsigned int clk_count;
> +	struct clk **clks;
> +#endif
> +#if defined CONFIG_OF && defined CONFIG_REGULATOR
> +	bool regulators_enabled;
> +	u32 regulator_count;
> +	struct regulator **regulators;
> +#endif
> +	bool release_mem_region;

Maybe instead you could have:

	struct resource *mem; 

that would be more consistent with the fields for the other
resources like clocks, regulators, etc.

> +};
> +
>  static void simplefb_clocks_destroy(struct simplefb_par *par);
>  static void simplefb_regulators_destroy(struct simplefb_par *par);
>  
>  static void simplefb_destroy(struct fb_info *info)
>  {
> +	struct simplefb_par *par = info->par;
> +
>  	simplefb_regulators_destroy(info->par);
>  	simplefb_clocks_destroy(info->par);
>  	if (info->screen_base)
>  		iounmap(info->screen_base);
> +
> +	if (par->release_mem_region)
> +		release_mem_region(info->apertures->ranges[0].base,
> +				   info->apertures->ranges[0].size);

and here you could instead use the pointer to the resource:

	if (par->mem)
		release_mem_region(par->mem->start, resource_size(par->mem));

[snip]

>  static int simplefb_probe(struct platform_device *pdev)
>  {
> +	bool request_mem_succeeded = false;
>  	int ret;
>  	struct simplefb_params params;
>  	struct fb_info *info;
> @@ -436,9 +443,22 @@ static int simplefb_probe(struct platform_device *pdev)
>  		return -EINVAL;
>  	}
>  
> +	if (request_mem_region(mem->start, resource_size(mem), "simplefb")) {
> +		request_mem_succeeded = true;

and if you do the request_mem_region() after the struct fb_info allocation then
this could just be:

		par->mem = mem;

Best regards,
-- 
Javier Martinez Canillas
Linux Engineering
Red Hat

[PATCH 4/5] fbdev/simplefb: Request memory region in driver

[Thomas Zimmermann]

Requesting the framebuffer memory in simpledrm marks the memory
range as busy. This used to be done by the firmware sysfb code,
but the driver is the correct place.

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
---
 drivers/video/fbdev/simplefb.c | 59 ++++++++++++++++++++++++----------
 1 file changed, 42 insertions(+), 17 deletions(-)

diff --git a/drivers/video/fbdev/simplefb.c b/drivers/video/fbdev/simplefb.c
index 57541887188b..84452028ecc9 100644
--- a/drivers/video/fbdev/simplefb.c
+++ b/drivers/video/fbdev/simplefb.c
@@ -66,16 +66,36 @@ static int simplefb_setcolreg(u_int regno, u_int red, u_int green, u_int blue,
 	return 0;
 }
 
-struct simplefb_par;
+struct simplefb_par {
+	u32 palette[PSEUDO_PALETTE_SIZE];
+#if defined CONFIG_OF && defined CONFIG_COMMON_CLK
+	bool clks_enabled;
+	unsigned int clk_count;
+	struct clk **clks;
+#endif
+#if defined CONFIG_OF && defined CONFIG_REGULATOR
+	bool regulators_enabled;
+	u32 regulator_count;
+	struct regulator **regulators;
+#endif
+	bool release_mem_region;
+};
+
 static void simplefb_clocks_destroy(struct simplefb_par *par);
 static void simplefb_regulators_destroy(struct simplefb_par *par);
 
 static void simplefb_destroy(struct fb_info *info)
 {
+	struct simplefb_par *par = info->par;
+
 	simplefb_regulators_destroy(info->par);
 	simplefb_clocks_destroy(info->par);
 	if (info->screen_base)
 		iounmap(info->screen_base);
+
+	if (par->release_mem_region)
+		release_mem_region(info->apertures->ranges[0].base,
+				   info->apertures->ranges[0].size);
 }
 
 static const struct fb_ops simplefb_ops = {
@@ -169,20 +189,6 @@ static int simplefb_parse_pd(struct platform_device *pdev,
 	return 0;
 }
 
-struct simplefb_par {
-	u32 palette[PSEUDO_PALETTE_SIZE];
-#if defined CONFIG_OF && defined CONFIG_COMMON_CLK
-	bool clks_enabled;
-	unsigned int clk_count;
-	struct clk **clks;
-#endif
-#if defined CONFIG_OF && defined CONFIG_REGULATOR
-	bool regulators_enabled;
-	u32 regulator_count;
-	struct regulator **regulators;
-#endif
-};
-
 #if defined CONFIG_OF && defined CONFIG_COMMON_CLK
 /*
  * Clock handling code.
@@ -401,6 +407,7 @@ static void simplefb_regulators_destroy(struct simplefb_par *par) { }
 
 static int simplefb_probe(struct platform_device *pdev)
 {
+	bool request_mem_succeeded = false;
 	int ret;
 	struct simplefb_params params;
 	struct fb_info *info;
@@ -436,9 +443,22 @@ static int simplefb_probe(struct platform_device *pdev)
 		return -EINVAL;
 	}
 
+	if (request_mem_region(mem->start, resource_size(mem), "simplefb")) {
+		request_mem_succeeded = true;
+	} else {
+		/*
+		 * We cannot make this fatal. Sometimes this comes from magic
+		 * spaces our resource handlers simply don't know about
+		 */
+		dev_warn(&pdev->dev, "simplefb: cannot reserve video memory at %pR\n",
+			 mem);
+	}
+
 	info = framebuffer_alloc(sizeof(struct simplefb_par), &pdev->dev);
-	if (!info)
-		return -ENOMEM;
+	if (!info) {
+		ret = -ENOMEM;
+		goto error_release_mem_region;
+	}
 	platform_set_drvdata(pdev, info);
 
 	par = info->par;
@@ -495,6 +515,8 @@ static int simplefb_probe(struct platform_device *pdev)
 			     info->var.xres, info->var.yres,
 			     info->var.bits_per_pixel, info->fix.line_length);
 
+	par->release_mem_region = request_mem_succeeded;
+
 	ret = register_framebuffer(info);
 	if (ret < 0) {
 		dev_err(&pdev->dev, "Unable to register simplefb: %d\n", ret);
@@ -513,6 +535,9 @@ static int simplefb_probe(struct platform_device *pdev)
 	iounmap(info->screen_base);
 error_fb_release:
 	framebuffer_release(info);
+error_release_mem_region:
+	if (request_mem_succeeded)
+		release_mem_region(mem->start, resource_size(mem));
 	return ret;
 }
 
-- 
2.34.1

[PATCH 4/5] fbdev/simplefb: Request memory region in driver

[Thomas Zimmermann]

Requesting the framebuffer memory in simpledrm marks the memory
range as busy. This used to be done by the firmware sysfb code,
but the driver is the correct place.

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
---
 drivers/video/fbdev/simplefb.c | 59 ++++++++++++++++++++++++----------
 1 file changed, 42 insertions(+), 17 deletions(-)

diff --git a/drivers/video/fbdev/simplefb.c b/drivers/video/fbdev/simplefb.c
index 57541887188b..84452028ecc9 100644
--- a/drivers/video/fbdev/simplefb.c
+++ b/drivers/video/fbdev/simplefb.c
@@ -66,16 +66,36 @@ static int simplefb_setcolreg(u_int regno, u_int red, u_int green, u_int blue,
 	return 0;
 }
 
-struct simplefb_par;
+struct simplefb_par {
+	u32 palette[PSEUDO_PALETTE_SIZE];
+#if defined CONFIG_OF && defined CONFIG_COMMON_CLK
+	bool clks_enabled;
+	unsigned int clk_count;
+	struct clk **clks;
+#endif
+#if defined CONFIG_OF && defined CONFIG_REGULATOR
+	bool regulators_enabled;
+	u32 regulator_count;
+	struct regulator **regulators;
+#endif
+	bool release_mem_region;
+};
+
 static void simplefb_clocks_destroy(struct simplefb_par *par);
 static void simplefb_regulators_destroy(struct simplefb_par *par);
 
 static void simplefb_destroy(struct fb_info *info)
 {
+	struct simplefb_par *par = info->par;
+
 	simplefb_regulators_destroy(info->par);
 	simplefb_clocks_destroy(info->par);
 	if (info->screen_base)
 		iounmap(info->screen_base);
+
+	if (par->release_mem_region)
+		release_mem_region(info->apertures->ranges[0].base,
+				   info->apertures->ranges[0].size);
 }
 
 static const struct fb_ops simplefb_ops = {
@@ -169,20 +189,6 @@ static int simplefb_parse_pd(struct platform_device *pdev,
 	return 0;
 }
 
-struct simplefb_par {
-	u32 palette[PSEUDO_PALETTE_SIZE];
-#if defined CONFIG_OF && defined CONFIG_COMMON_CLK
-	bool clks_enabled;
-	unsigned int clk_count;
-	struct clk **clks;
-#endif
-#if defined CONFIG_OF && defined CONFIG_REGULATOR
-	bool regulators_enabled;
-	u32 regulator_count;
-	struct regulator **regulators;
-#endif
-};
-
 #if defined CONFIG_OF && defined CONFIG_COMMON_CLK
 /*
  * Clock handling code.
@@ -401,6 +407,7 @@ static void simplefb_regulators_destroy(struct simplefb_par *par) { }
 
 static int simplefb_probe(struct platform_device *pdev)
 {
+	bool request_mem_succeeded = false;
 	int ret;
 	struct simplefb_params params;
 	struct fb_info *info;
@@ -436,9 +443,22 @@ static int simplefb_probe(struct platform_device *pdev)
 		return -EINVAL;
 	}
 
+	if (request_mem_region(mem->start, resource_size(mem), "simplefb")) {
+		request_mem_succeeded = true;
+	} else {
+		/*
+		 * We cannot make this fatal. Sometimes this comes from magic
+		 * spaces our resource handlers simply don't know about
+		 */
+		dev_warn(&pdev->dev, "simplefb: cannot reserve video memory at %pR\n",
+			 mem);
+	}
+
 	info = framebuffer_alloc(sizeof(struct simplefb_par), &pdev->dev);
-	if (!info)
-		return -ENOMEM;
+	if (!info) {
+		ret = -ENOMEM;
+		goto error_release_mem_region;
+	}
 	platform_set_drvdata(pdev, info);
 
 	par = info->par;
@@ -495,6 +515,8 @@ static int simplefb_probe(struct platform_device *pdev)
 			     info->var.xres, info->var.yres,
 			     info->var.bits_per_pixel, info->fix.line_length);
 
+	par->release_mem_region = request_mem_succeeded;
+
 	ret = register_framebuffer(info);
 	if (ret < 0) {
 		dev_err(&pdev->dev, "Unable to register simplefb: %d\n", ret);
@@ -513,6 +535,9 @@ static int simplefb_probe(struct platform_device *pdev)
 	iounmap(info->screen_base);
 error_fb_release:
 	framebuffer_release(info);
+error_release_mem_region:
+	if (request_mem_succeeded)
+		release_mem_region(mem->start, resource_size(mem));
 	return ret;
 }
 
-- 
2.34.1