* [PATCH] fbdev: xilinxfb: request memory region before mapping framebuffer
@ 2025-12-15 22:53 patdiviyam
2025-12-30 9:57 ` Helge Deller
0 siblings, 1 reply; 3+ messages in thread
From: patdiviyam @ 2025-12-15 22:53 UTC (permalink / raw)
To: dri-devel; +Cc: tzimmermann, deller, linux-fbdev, DiviyamPathak
From: DiviyamPathak <patdiviyam@gmail.com>
The xilinxfb driver maps a physical framebuffer address with ioremap()
without first reserving the memory region. This can conflict with other
drivers accessing the same resource.
Request the memory region with devm_request_mem_region() before mapping
the framebuffer and use managed mappings for proper lifetime handling.
This addresses the fbdev TODO about requesting memory regions and avoids
potential resource conflicts.
Signed-off-by: DiviyamPathak <patdiviyam@gmail.com>
---
drivers/video/fbdev/xilinxfb.c | 30 +++++++++++++++++-------------
1 file changed, 17 insertions(+), 13 deletions(-)
diff --git a/drivers/video/fbdev/xilinxfb.c b/drivers/video/fbdev/xilinxfb.c
index 0a6e05cd155a..f18437490de8 100644
--- a/drivers/video/fbdev/xilinxfb.c
+++ b/drivers/video/fbdev/xilinxfb.c
@@ -280,19 +280,27 @@ static int xilinxfb_assign(struct platform_device *pdev,
/* Allocate the framebuffer memory */
if (pdata->fb_phys) {
drvdata->fb_phys = pdata->fb_phys;
- drvdata->fb_virt = ioremap(pdata->fb_phys, fbsize);
+ /* Request the memory region before mapping */
+ if (!devm_request_mem_region(dev, pdata->fb_phys, fbsize,
+ DRIVER_NAME)) {
+ dev_err(dev, "Cannot request framebuffer memory region\n");
+ return -EBUSY;
+ }
+ drvdata->fb_virt = devm_ioremap(dev, pdata->fb_phys, fbsize);
+ if (!drvdata->fb_virt) {
+ dev_err(dev, "Could not map framebuffer memory\n");
+ return -ENOMEM;
+ }
} else {
drvdata->fb_alloced = 1;
drvdata->fb_virt = dma_alloc_coherent(dev, PAGE_ALIGN(fbsize),
- &drvdata->fb_phys,
- GFP_KERNEL);
- }
-
- if (!drvdata->fb_virt) {
- dev_err(dev, "Could not allocate frame buffer memory\n");
- return -ENOMEM;
+ &drvdata->fb_phys,
+ GFP_KERNEL);
+ if (!drvdata->fb_virt) {
+ dev_err(dev, "Could not allocate frame buffer memory\n");
+ return -ENOMEM;
+ }
}
-
/* Clear (turn to black) the framebuffer */
memset_io((void __iomem *)drvdata->fb_virt, 0, fbsize);
@@ -362,8 +370,6 @@ static int xilinxfb_assign(struct platform_device *pdev,
if (drvdata->fb_alloced)
dma_free_coherent(dev, PAGE_ALIGN(fbsize), drvdata->fb_virt,
drvdata->fb_phys);
- else
- iounmap(drvdata->fb_virt);
/* Turn off the display */
xilinx_fb_out32(drvdata, REG_CTRL, 0);
@@ -386,8 +392,6 @@ static void xilinxfb_release(struct device *dev)
if (drvdata->fb_alloced)
dma_free_coherent(dev, PAGE_ALIGN(drvdata->info.fix.smem_len),
drvdata->fb_virt, drvdata->fb_phys);
- else
- iounmap(drvdata->fb_virt);
/* Turn off the display */
xilinx_fb_out32(drvdata, REG_CTRL, 0);
--
2.43.0
^ permalink raw reply related [flat|nested] 3+ messages in thread* Re: [PATCH] fbdev: xilinxfb: request memory region before mapping framebuffer
2025-12-15 22:53 [PATCH] fbdev: xilinxfb: request memory region before mapping framebuffer patdiviyam
@ 2025-12-30 9:57 ` Helge Deller
[not found] ` <CAM19b+s73Fo6Ej85qk72UPn12VQ_iFAYpHv7K=wOapb0-+1XBA@mail.gmail.com>
0 siblings, 1 reply; 3+ messages in thread
From: Helge Deller @ 2025-12-30 9:57 UTC (permalink / raw)
To: patdiviyam; +Cc: tzimmermann, linux-fbdev, dri-devel
On 12/15/25 23:53, patdiviyam@gmail.com wrote:
> From: DiviyamPathak <patdiviyam@gmail.com>
>
> The xilinxfb driver maps a physical framebuffer address with ioremap()
> without first reserving the memory region. This can conflict with other
> drivers accessing the same resource.
>
> Request the memory region with devm_request_mem_region() before mapping
> the framebuffer and use managed mappings for proper lifetime handling.
>
> This addresses the fbdev TODO about requesting memory regions and avoids
> potential resource conflicts.
>
> Signed-off-by: DiviyamPathak <patdiviyam@gmail.com>
Was it tested it on physical hardware?
If not, could someone test?
Helge
> ---
> drivers/video/fbdev/xilinxfb.c | 30 +++++++++++++++++-------------
> 1 file changed, 17 insertions(+), 13 deletions(-)
>
> diff --git a/drivers/video/fbdev/xilinxfb.c b/drivers/video/fbdev/xilinxfb.c
> index 0a6e05cd155a..f18437490de8 100644
> --- a/drivers/video/fbdev/xilinxfb.c
> +++ b/drivers/video/fbdev/xilinxfb.c
> @@ -280,19 +280,27 @@ static int xilinxfb_assign(struct platform_device *pdev,
> /* Allocate the framebuffer memory */
> if (pdata->fb_phys) {
> drvdata->fb_phys = pdata->fb_phys;
> - drvdata->fb_virt = ioremap(pdata->fb_phys, fbsize);
> + /* Request the memory region before mapping */
> + if (!devm_request_mem_region(dev, pdata->fb_phys, fbsize,
> + DRIVER_NAME)) {
> + dev_err(dev, "Cannot request framebuffer memory region\n");
> + return -EBUSY;
> + }
> + drvdata->fb_virt = devm_ioremap(dev, pdata->fb_phys, fbsize);
> + if (!drvdata->fb_virt) {
> + dev_err(dev, "Could not map framebuffer memory\n");
> + return -ENOMEM;
> + }
> } else {
> drvdata->fb_alloced = 1;
> drvdata->fb_virt = dma_alloc_coherent(dev, PAGE_ALIGN(fbsize),
> - &drvdata->fb_phys,
> - GFP_KERNEL);
> - }
> -
> - if (!drvdata->fb_virt) {
> - dev_err(dev, "Could not allocate frame buffer memory\n");
> - return -ENOMEM;
> + &drvdata->fb_phys,
> + GFP_KERNEL);
> + if (!drvdata->fb_virt) {
> + dev_err(dev, "Could not allocate frame buffer memory\n");
> + return -ENOMEM;
> + }
> }
> -
> /* Clear (turn to black) the framebuffer */
> memset_io((void __iomem *)drvdata->fb_virt, 0, fbsize);
>
> @@ -362,8 +370,6 @@ static int xilinxfb_assign(struct platform_device *pdev,
> if (drvdata->fb_alloced)
> dma_free_coherent(dev, PAGE_ALIGN(fbsize), drvdata->fb_virt,
> drvdata->fb_phys);
> - else
> - iounmap(drvdata->fb_virt);
>
> /* Turn off the display */
> xilinx_fb_out32(drvdata, REG_CTRL, 0);
> @@ -386,8 +392,6 @@ static void xilinxfb_release(struct device *dev)
> if (drvdata->fb_alloced)
> dma_free_coherent(dev, PAGE_ALIGN(drvdata->info.fix.smem_len),
> drvdata->fb_virt, drvdata->fb_phys);
> - else
> - iounmap(drvdata->fb_virt);
>
> /* Turn off the display */
> xilinx_fb_out32(drvdata, REG_CTRL, 0);
^ permalink raw reply [flat|nested] 3+ messages in thread
end of thread, other threads:[~2025-12-31 1:13 UTC | newest]
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2025-12-15 22:53 [PATCH] fbdev: xilinxfb: request memory region before mapping framebuffer patdiviyam
2025-12-30 9:57 ` Helge Deller
[not found] ` <CAM19b+s73Fo6Ej85qk72UPn12VQ_iFAYpHv7K=wOapb0-+1XBA@mail.gmail.com>
2025-12-31 1:12 ` Diviyam Pat
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