Hi Hans

On Tue, Jun 26, 2018 at 3:38 PM, Michael Nazzareno Trimarchi
[off-list ref] wrote:

Hi

On Tue, Jun 26, 2018 at 3:36 PM, Hans de Goede [off-list ref] wrote:

quoted

Hi,


On 26-06-18 15:29, Michael Nazzareno Trimarchi wrote:

quoted

Hi

to be more specific

On Tue, Jun 26, 2018 at 3:06 PM, Michael Nazzareno Trimarchi
[off-list ref] wrote:

quoted

Hi

On Tue., 26 Jun. 2018, 12:01 pm Hans de Goede, [off-list ref]
wrote:

quoted

Hi,

On 25-06-18 15:29, Michael Nazzareno Trimarchi wrote:

quoted

Hi Hans

In order to let it even registered the simplefb I have added this
change. According on what I understand
from the code seems that this is the way to acquire memory with the
correct attribute

diff --git a/drivers/video/fbdev/simplefb.c

b/drivers/video/fbdev/simplefb.c
index a3c44ec..7e61ce3 100644

--- a/drivers/video/fbdev/simplefb.c
+++ b/drivers/video/fbdev/simplefb.c

@@ -466,8 +466,8 @@ static int simplefb_probe(struct platform_device

*pdev)

          info->fbops = &simplefb_ops;
          info->flags = FBINFO_DEFAULT | FBINFO_MISC_FIRMWARE;
-       info->screen_base = ioremap_wc(info->fix.smem_start,
-                                      info->fix.smem_len);
+       info->screen_base = arch_memremap_wb(info->fix.smem_start,
+                                            info->fix.smem_len);

I'm not sure why you need this?  wb certainly is not optimal
for a framebuffer, the existing wc mapping is really what you
want.

Well in this way raise a WARN and get a nice NULL on memory remap on
imx6ull
SoC

[    0.397484] WARNING: CPU: 0 PID: 1 at arch/arm/mm/ioremap.c:303
__arm_ioremap_pfn_caller+0x80/0x1cc

This is causes by a mismatch in memory attributes, which means the
memory is already mapped by the kernel as regular RAM and may
already be used for other purposes by the kernel!

Memory used by a simplefb framebuffer must be reserved by the
bootloader, so that it does not get used by the kernel as regular
RAM. See e.g.:

http://git.denx.de/?p=u-boot.git;a=blob;f=drivers/video/sunxi/sunxi_display.c

Near the end of the file where the framebuffer RAM gets excluded from
the memory-range reported to the kernel as usable RAM. Note this relies
on the u-boot sunxi video code putting the framebuffer at the end of the
RAM.

+       aliases {
+               display0 = &lcdif;
+       };
+
+       reserved-memory {
+               #address-cells = <1>;
+               #size-cells = <1>;
+               ranges;
+
+               display_reserved: framebuffer@86fd6080 {
+                       reg = <0x86fd6080 (480 * 272 *4)>;
+               };
+

This should do the trick but I have still the same problem on memory
type. Any idea?


+               linux,cma {
+                       compatible = "shared-dma-pool";
+                       reusable;
+                       size = <0x1000000>;
+                       linux,cma-default;
+               };
+       };
+
+       chosen {
+               #address-cells = <1>;
+               #size-cells = <1>;
+               ranges;
+
+               stdout-path = &uart1;
+               framebuffer0: framebuffer@86fd6080 {
+                       compatible = "simple-framebuffer";
+                       reg = <0x86fd6080 (480 * 272 * 4)>;

Here I try to use the same. I will create in uboot a dynamic way to
track down. I think that
we can even add to the simple buffer a way to get hand of reserved
region automatically

Michael

+                       width = <480>;
+                       height = <272>;
+                       stride = <(480 * 4)>;
+                       format = "a8r8g8b8";
+                       clocks = <&clks IMX6UL_CLK_LCDIF_PIX>,
+                                <&clks IMX6UL_CLK_LCDIF_APB>,
+                                <&clks IMX6UL_CLK_DUMMY>,
+                                <&clks IMX6UL_CLK_GPIO3>,
+                                <&clks IMX6UL_CLK_GPIO4>;
+                       nshut-supply = <&reg_lcd_nshut>;
+                       nreset-supply = <&reg_lcd_nreset>;
+                       display = <&lcdif>;
+                       status = "okay";
+               };

quoted

Thank you very much for this lesson ;). I will try to document better
after my tour ;)

Michael

quoted

Regards,

Hans

--
| Michael Nazzareno Trimarchi                     Amarula Solutions BV |
| COO  -  Founder                                      Cruquiuskade 47 |
| +31(0)851119172                                 Amsterdam 1018 AM NL |
|                  [`as] http://www.amarulasolutions.com               |

-- 
| Michael Nazzareno Trimarchi                     Amarula Solutions BV |
| COO  -  Founder                                      Cruquiuskade 47 |
| +31(0)851119172                                 Amsterdam 1018 AM NL |
|                  [`as] http://www.amarulasolutions.com               |