[PATCH 0/2] rpi: Copy properties from firmware DT to loaded DT

[PATCH 0/2] rpi: Copy properties from firmware DT to loaded DT

[Antoine Mazeas]

Sjoerd Simons submitted the original patch (0001) to carry over some firmware-provided properties into the loaded device tree. This did not fix an issue with Raspberry Pi 400 rev 1.1 boards which would not be able to find the ethernet PHY device at the address specified by the kernel device tree.

Patch 0002 expands on Sjoerd's design to also carry over the real ethernet PHY address, enabling the kernel to find and enable a working ethernet on pi 400 rev 1.1 boards.

Antoine Mazeas (2):
  rpi: Copy properties from firmware dtb to the loaded dtb
  rpi: Copy eth PHY address from fw DT to loaded DT

 board/raspberrypi/rpi/rpi.c | 51 +++++++++++++++++++++++++++++++++++++
 1 file changed, 51 insertions(+)


base-commit: 3dd4e916324efc825a7ee8e412f5cf1ded839021
-- 
2.37.1

[PATCH 1/2] rpi: Copy properties from firmware dtb to the loaded dtb

[Antoine Mazeas]

The RPI firmware adjusts several property values in the dtb it passes
to u-boot depending on the board/SoC revision. Inherit some of these
when u-boot loads a dtb itself. Specificaly copy:

* /model: The firmware provides a more specific string
* /memreserve: The firmware defines a reserved range, better keep it
* emmc2bus and pcie0 dma-ranges: The C0T revision of the bcm2711 Soc (as
  present on rpi 400 and some rpi 4B boards) has different values for
  these then the B0T revision. So these need to be adjusted to boot on
  these boards
* blconfig: The firmware defines the memory area where the blconfig
  stored. Copy those over so it can be enabled.
* /chosen/kaslr-seed: The firmware generates a kaslr seed, take advantage
  of that.

Signed-off-by: Sjoerd Simons <sjoerd@collabora.com>
---
 board/raspberrypi/rpi/rpi.c | 48 +++++++++++++++++++++++++++++++++++++
 1 file changed, 48 insertions(+)

diff --git a/board/raspberrypi/rpi/rpi.c b/board/raspberrypi/rpi/rpi.c
index 17b8108cc8..28b6f52506 100644
--- a/board/raspberrypi/rpi/rpi.c
+++ b/board/raspberrypi/rpi/rpi.c
@@ -504,10 +504,58 @@ void *board_fdt_blob_setup(int *err)
 	return (void *)fw_dtb_pointer;
 }
 
+int copy_property(void *dst, void *src, char *path, char *property)
+{
+	int dst_offset, src_offset;
+	const fdt32_t *prop;
+	int len;
+
+	src_offset = fdt_path_offset(src, path);
+	dst_offset = fdt_path_offset(dst, path);
+
+	if (src_offset < 0 || dst_offset < 0)
+		return -1;
+
+	prop = fdt_getprop(src, src_offset, property, &len);
+	if (!prop)
+		return -1;
+
+	return fdt_setprop(dst, dst_offset, property, prop, len);
+}
+
+/* Copy tweaks from the firmware dtb to the loaded dtb */
+void  update_fdt_from_fw(void *fdt, void *fw_fdt)
+{
+	/* Using dtb from firmware directly; leave it alone */
+	if (fdt == fw_fdt)
+		return;
+
+	/* The firmware provides a more precie model; so copy that */
+	copy_property(fdt, fw_fdt, "/", "model");
+
+	/* memory reserve as suggested by the firmware */
+	copy_property(fdt, fw_fdt, "/", "memreserve");
+
+	/* Adjust dma-ranges for the SD card and PCI bus as they can depend on
+	 * the SoC revision
+	 */
+	copy_property(fdt, fw_fdt, "emmc2bus", "dma-ranges");
+	copy_property(fdt, fw_fdt, "pcie0", "dma-ranges");
+
+	/* Bootloader configuration template exposes as nvmem */
+	if (copy_property(fdt, fw_fdt, "blconfig", "reg") == 0)
+		copy_property(fdt, fw_fdt, "blconfig", "status");
+
+	/* kernel address randomisation seed as provided by the firmware */
+	copy_property(fdt, fw_fdt, "/chosen", "kaslr-seed");
+}
+
 int ft_board_setup(void *blob, struct bd_info *bd)
 {
 	int node;
 
+	update_fdt_from_fw(blob, (void *)fw_dtb_pointer);
+
 	node = fdt_node_offset_by_compatible(blob, -1, "simple-framebuffer");
 	if (node < 0)
 		fdt_simplefb_add_node(blob);
-- 
2.37.1

[PATCH 2/2] rpi: Copy eth PHY address from fw DT to loaded DT

[Antoine Mazeas]

Some Raspberry Pi 400 boards, specifically rev 1.1, have a different address for the ethernet PHY device than what is provided by the kernel DTB. The correct address is provided by the firmware, so we should carry it over into the loaded device tree so that ethernet works on such boards.

Signed-off-by: Antoine Mazeas <antoine@karthanis.net>
---
 board/raspberrypi/rpi/rpi.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/board/raspberrypi/rpi/rpi.c b/board/raspberrypi/rpi/rpi.c
index 28b6f52506..793fd1aa30 100644
--- a/board/raspberrypi/rpi/rpi.c
+++ b/board/raspberrypi/rpi/rpi.c
@@ -548,6 +548,9 @@ void  update_fdt_from_fw(void *fdt, void *fw_fdt)
 
 	/* kernel address randomisation seed as provided by the firmware */
 	copy_property(fdt, fw_fdt, "/chosen", "kaslr-seed");
+
+	/* address of the PHY device as provided by the firmware  */
+	copy_property(fdt, fw_fdt, "ethernet0/mdio@e14/ethernet-phy@1", "reg");
 }
 
 int ft_board_setup(void *blob, struct bd_info *bd)
-- 
2.37.1

Re: [PATCH 2/2] rpi: Copy eth PHY address from fw DT to loaded DT

[Peter Robinson]

On Wed, Aug 10, 2022 at 1:58 PM Antoine Mazeas <antoine@karthanis.net> wrote:
>
> Some Raspberry Pi 400 boards, specifically rev 1.1, have a different address for the ethernet PHY device than what is provided by the kernel DTB. The correct address is provided by the firmware, so we should carry it over into the loaded device tree so that ethernet works on such boards.

Minor nit: this should be properly wrapped.

> Signed-off-by: Antoine Mazeas <antoine@karthanis.net>

Reviewed-by: Peter Robinson <pbrobinson@gmail.com>
Tested-by: Peter Robinson <pbrobinson@gmail.com>

Tested on the RPi400 and a couple of different RPi4s

> ---
>  board/raspberrypi/rpi/rpi.c | 3 +++
>  1 file changed, 3 insertions(+)
>
> diff --git a/board/raspberrypi/rpi/rpi.c b/board/raspberrypi/rpi/rpi.c
> index 28b6f52506..793fd1aa30 100644
> --- a/board/raspberrypi/rpi/rpi.c
> +++ b/board/raspberrypi/rpi/rpi.c
> @@ -548,6 +548,9 @@ void  update_fdt_from_fw(void *fdt, void *fw_fdt)
>
>         /* kernel address randomisation seed as provided by the firmware */
>         copy_property(fdt, fw_fdt, "/chosen", "kaslr-seed");
> +
> +       /* address of the PHY device as provided by the firmware  */
> +       copy_property(fdt, fw_fdt, "ethernet0/mdio@e14/ethernet-phy@1", "reg");
>  }
>
>  int ft_board_setup(void *blob, struct bd_info *bd)
> --
> 2.37.1
>

Re: [PATCH 1/2] rpi: Copy properties from firmware dtb to the loaded dtb

[Peter Robinson]

On Wed, Aug 10, 2022 at 1:58 PM Antoine Mazeas <antoine@karthanis.net> wrote:
>
> The RPI firmware adjusts several property values in the dtb it passes
> to u-boot depending on the board/SoC revision. Inherit some of these
> when u-boot loads a dtb itself. Specificaly copy:
>
> * /model: The firmware provides a more specific string
> * /memreserve: The firmware defines a reserved range, better keep it

Is this the CMA range or a different one? If so this makes sense.

> * emmc2bus and pcie0 dma-ranges: The C0T revision of the bcm2711 Soc (as
>   present on rpi 400 and some rpi 4B boards) has different values for
>   these then the B0T revision. So these need to be adjusted to boot on
>   these boards
> * blconfig: The firmware defines the memory area where the blconfig
>   stored. Copy those over so it can be enabled.
> * /chosen/kaslr-seed: The firmware generates a kaslr seed, take advantage
>   of that.

U-Boot has a rpi4 iproc_rng200 driver for this and provides it via the
UEFI random seed as well, if you're booting using UEFI that takes
precedence so providing this might not be useful but also it doesn't
matter much.

> Signed-off-by: Sjoerd Simons <sjoerd@collabora.com>

Reviewed-by: Peter Robinson <pbrobinson@gmail.com>
Tested-by: Peter Robinson <pbrobinson@gmail.com>

Tested on RPi400 and it solves the issues with the kernel DT I've seen
plus some RPi4s although no the rev 1.3+ devices that also have the
newer SoC rev that's the same in the rpi400

> ---
>  board/raspberrypi/rpi/rpi.c | 48 +++++++++++++++++++++++++++++++++++++
>  1 file changed, 48 insertions(+)
>
> diff --git a/board/raspberrypi/rpi/rpi.c b/board/raspberrypi/rpi/rpi.c
> index 17b8108cc8..28b6f52506 100644
> --- a/board/raspberrypi/rpi/rpi.c
> +++ b/board/raspberrypi/rpi/rpi.c
> @@ -504,10 +504,58 @@ void *board_fdt_blob_setup(int *err)
>         return (void *)fw_dtb_pointer;
>  }
>
> +int copy_property(void *dst, void *src, char *path, char *property)
> +{
> +       int dst_offset, src_offset;
> +       const fdt32_t *prop;
> +       int len;
> +
> +       src_offset = fdt_path_offset(src, path);
> +       dst_offset = fdt_path_offset(dst, path);
> +
> +       if (src_offset < 0 || dst_offset < 0)
> +               return -1;
> +
> +       prop = fdt_getprop(src, src_offset, property, &len);
> +       if (!prop)
> +               return -1;
> +
> +       return fdt_setprop(dst, dst_offset, property, prop, len);
> +}
> +
> +/* Copy tweaks from the firmware dtb to the loaded dtb */
> +void  update_fdt_from_fw(void *fdt, void *fw_fdt)
> +{
> +       /* Using dtb from firmware directly; leave it alone */
> +       if (fdt == fw_fdt)
> +               return;
> +
> +       /* The firmware provides a more precie model; so copy that */
> +       copy_property(fdt, fw_fdt, "/", "model");
> +
> +       /* memory reserve as suggested by the firmware */
> +       copy_property(fdt, fw_fdt, "/", "memreserve");
> +
> +       /* Adjust dma-ranges for the SD card and PCI bus as they can depend on
> +        * the SoC revision
> +        */
> +       copy_property(fdt, fw_fdt, "emmc2bus", "dma-ranges");
> +       copy_property(fdt, fw_fdt, "pcie0", "dma-ranges");
> +
> +       /* Bootloader configuration template exposes as nvmem */
> +       if (copy_property(fdt, fw_fdt, "blconfig", "reg") == 0)
> +               copy_property(fdt, fw_fdt, "blconfig", "status");
> +
> +       /* kernel address randomisation seed as provided by the firmware */
> +       copy_property(fdt, fw_fdt, "/chosen", "kaslr-seed");
> +}
> +
>  int ft_board_setup(void *blob, struct bd_info *bd)
>  {
>         int node;
>
> +       update_fdt_from_fw(blob, (void *)fw_dtb_pointer);
> +
>         node = fdt_node_offset_by_compatible(blob, -1, "simple-framebuffer");
>         if (node < 0)
>                 fdt_simplefb_add_node(blob);
> --
> 2.37.1
>

Re: [PATCH 1/2] rpi: Copy properties from firmware dtb to the loaded dtb

[Antoine Mazeas]

Hi Peter,
Thanks for looking at this patch

Le 05/09/2022 à 15:41, Peter Robinson a écrit :
> On Wed, Aug 10, 2022 at 1:58 PM Antoine Mazeas <antoine@karthanis.net> wrote:
>>
>> The RPI firmware adjusts several property values in the dtb it passes
>> to u-boot depending on the board/SoC revision. Inherit some of these
>> when u-boot loads a dtb itself. Specificaly copy:
>>
>> * /model: The firmware provides a more specific string
>> * /memreserve: The firmware defines a reserved range, better keep it
> 
> Is this the CMA range or a different one? If so this makes sense.

This a different range than that of the CMA (which itself is defined at 
/reserved-memory/linux,cma): it's a reserved memory range for the 
VideoCore module on the SoC. In the case of the rpi 400 (and sister 
boards like 4B based on the same chip), the dummy value in the DTB is 
patched by the firmware to a dynamic value set in config.txt; absent 
this config, the default amount is 76 MiBs (see: datasheet 
https://datasheets.raspberrypi.com/bcm2711/bcm2711-peripherals.pdf and 
rpi config reference 
https://www.raspberrypi.com/documentation/computers/config_txt.html#memory-options). 
I can see this happening on my board, where looking at the device tree 
on a running system:

memreserve = <0x3b400000 0x4c00000>; // 0x4c00000 == 76 MiBs

Note the start of the range is also patched in. Given the dynamic nature 
of this setting on at least bcm2711 rpi boards, I think this is worth 
carrying over.

>> * emmc2bus and pcie0 dma-ranges: The C0T revision of the bcm2711 Soc (as
>>    present on rpi 400 and some rpi 4B boards) has different values for
>>    these then the B0T revision. So these need to be adjusted to boot on
>>    these boards
>> * blconfig: The firmware defines the memory area where the blconfig
>>    stored. Copy those over so it can be enabled.
>> * /chosen/kaslr-seed: The firmware generates a kaslr seed, take advantage
>>    of that.
> 
> U-Boot has a rpi4 iproc_rng200 driver for this and provides it via the
> UEFI random seed as well, if you're booting using UEFI that takes
> precedence so providing this might not be useful but also it doesn't
> matter much.
> 
>> Signed-off-by: Sjoerd Simons <sjoerd@collabora.com>
> 
> Reviewed-by: Peter Robinson <pbrobinson@gmail.com>
> Tested-by: Peter Robinson <pbrobinson@gmail.com>
> 
> Tested on RPi400 and it solves the issues with the kernel DT I've seen
> plus some RPi4s although no the rev 1.3+ devices that also have the
> newer SoC rev that's the same in the rpi400
> 
>> ---
>>   board/raspberrypi/rpi/rpi.c | 48 +++++++++++++++++++++++++++++++++++++
>>   1 file changed, 48 insertions(+)
>>
>> diff --git a/board/raspberrypi/rpi/rpi.c b/board/raspberrypi/rpi/rpi.c
>> index 17b8108cc8..28b6f52506 100644
>> --- a/board/raspberrypi/rpi/rpi.c
>> +++ b/board/raspberrypi/rpi/rpi.c
>> @@ -504,10 +504,58 @@ void *board_fdt_blob_setup(int *err)
>>          return (void *)fw_dtb_pointer;
>>   }
>>
>> +int copy_property(void *dst, void *src, char *path, char *property)
>> +{
>> +       int dst_offset, src_offset;
>> +       const fdt32_t *prop;
>> +       int len;
>> +
>> +       src_offset = fdt_path_offset(src, path);
>> +       dst_offset = fdt_path_offset(dst, path);
>> +
>> +       if (src_offset < 0 || dst_offset < 0)
>> +               return -1;
>> +
>> +       prop = fdt_getprop(src, src_offset, property, &len);
>> +       if (!prop)
>> +               return -1;
>> +
>> +       return fdt_setprop(dst, dst_offset, property, prop, len);
>> +}
>> +
>> +/* Copy tweaks from the firmware dtb to the loaded dtb */
>> +void  update_fdt_from_fw(void *fdt, void *fw_fdt)
>> +{
>> +       /* Using dtb from firmware directly; leave it alone */
>> +       if (fdt == fw_fdt)
>> +               return;
>> +
>> +       /* The firmware provides a more precie model; so copy that */
>> +       copy_property(fdt, fw_fdt, "/", "model");
>> +
>> +       /* memory reserve as suggested by the firmware */
>> +       copy_property(fdt, fw_fdt, "/", "memreserve");
>> +
>> +       /* Adjust dma-ranges for the SD card and PCI bus as they can depend on
>> +        * the SoC revision
>> +        */
>> +       copy_property(fdt, fw_fdt, "emmc2bus", "dma-ranges");
>> +       copy_property(fdt, fw_fdt, "pcie0", "dma-ranges");
>> +
>> +       /* Bootloader configuration template exposes as nvmem */
>> +       if (copy_property(fdt, fw_fdt, "blconfig", "reg") == 0)
>> +               copy_property(fdt, fw_fdt, "blconfig", "status");
>> +
>> +       /* kernel address randomisation seed as provided by the firmware */
>> +       copy_property(fdt, fw_fdt, "/chosen", "kaslr-seed");
>> +}
>> +
>>   int ft_board_setup(void *blob, struct bd_info *bd)
>>   {
>>          int node;
>>
>> +       update_fdt_from_fw(blob, (void *)fw_dtb_pointer);
>> +
>>          node = fdt_node_offset_by_compatible(blob, -1, "simple-framebuffer");
>>          if (node < 0)
>>                  fdt_simplefb_add_node(blob);
>> --
>> 2.37.1
>>

Re: [PATCH 1/2] rpi: Copy properties from firmware dtb to the loaded dtb

[Antoine Mazeas]

Sorry following up on your last comment, what specific issues are you 
referring to on the rev 1.3+ pi 4s ? It may be worth hunting them down, 
although I may lack access to such boards.

Le 05/09/2022 à 15:41, Peter Robinson a écrit :
> Tested on RPi400 and it solves the issues with the kernel DT I've seen
> plus some RPi4s although no the rev 1.3+ devices that also have the
> newer SoC rev that's the same in the rpi400

Re: [PATCH 2/2] rpi: Copy eth PHY address from fw DT to loaded DT

[Antoine Mazeas]

Le 05/09/2022 à 15:19, Peter Robinson a écrit :
> On Wed, Aug 10, 2022 at 1:58 PM Antoine Mazeas <antoine@karthanis.net> wrote:
>>
>> Some Raspberry Pi 400 boards, specifically rev 1.1, have a different address for the ethernet PHY device than what is provided by the kernel DTB. The correct address is provided by the firmware, so we should carry it over into the loaded device tree so that ethernet works on such boards.
> 
> Minor nit: this should be properly wrapped.

Yes, I did end up resending the patch a few days later with proper 
formatting and superseding this series. I'm very sorry for the confusion.

Resent on the 19th Aug.: 
https://patchwork.ozlabs.org/project/uboot/list/?series=314524

No change apart from the formatting of the commit messages.

>> Signed-off-by: Antoine Mazeas <antoine@karthanis.net>
> 
> Reviewed-by: Peter Robinson <pbrobinson@gmail.com>
> Tested-by: Peter Robinson <pbrobinson@gmail.com>
> 
> Tested on the RPi400 and a couple of different RPi4s
> 
>> ---
>>   board/raspberrypi/rpi/rpi.c | 3 +++
>>   1 file changed, 3 insertions(+)
>>
>> diff --git a/board/raspberrypi/rpi/rpi.c b/board/raspberrypi/rpi/rpi.c
>> index 28b6f52506..793fd1aa30 100644
>> --- a/board/raspberrypi/rpi/rpi.c
>> +++ b/board/raspberrypi/rpi/rpi.c
>> @@ -548,6 +548,9 @@ void  update_fdt_from_fw(void *fdt, void *fw_fdt)
>>
>>          /* kernel address randomisation seed as provided by the firmware */
>>          copy_property(fdt, fw_fdt, "/chosen", "kaslr-seed");
>> +
>> +       /* address of the PHY device as provided by the firmware  */
>> +       copy_property(fdt, fw_fdt, "ethernet0/mdio@e14/ethernet-phy@1", "reg");
>>   }
>>
>>   int ft_board_setup(void *blob, struct bd_info *bd)
>> --
>> 2.37.1
>>

Re: [PATCH 1/2] rpi: Copy properties from firmware dtb to the loaded dtb

[Sjoerd Simons]

On Mon, 2022-09-05 at 21:11 +0200, Antoine Mazeas wrote:
> Sorry following up on your last comment, what specific issues are you
> referring to on the rev 1.3+ pi 4s ? It may be worth hunting them
> down, 
> although I may lack access to such boards.
> 
> Le 05/09/2022 à 15:41, Peter Robinson a écrit :
> > Tested on RPi400 and it solves the issues with the kernel DT I've
> > seen
> > plus some RPi4s although no the rev 1.3+ devices that also have the
> > newer SoC rev that's the same in the rpi400

For reference the newer RPI4 boards is why i wrote the patch in the
first place as some folks in our team were hitting issues with them :)
So i can confirm my patch solves the issue there as well;

Unfortunately i don't have newer revisions RPI4's myself, but behaviour
wise they seem the same as the RPI 400 as they share the same SoC
revision
-- 
Sjoerd Simons
Collabora Ltd.

Re: [PATCH 2/2] rpi: Copy eth PHY address from fw DT to loaded DT

[Peter Robinson]

On Mon, Sep 5, 2022 at 8:16 PM Antoine Mazeas <antoine@karthanis.net> wrote:
>
> Le 05/09/2022 à 15:19, Peter Robinson a écrit :
> > On Wed, Aug 10, 2022 at 1:58 PM Antoine Mazeas <antoine@karthanis.net> wrote:
> >>
> >> Some Raspberry Pi 400 boards, specifically rev 1.1, have a different address for the ethernet PHY device than what is provided by the kernel DTB. The correct address is provided by the firmware, so we should carry it over into the loaded device tree so that ethernet works on such boards.
> >
> > Minor nit: this should be properly wrapped.
>
> Yes, I did end up resending the patch a few days later with proper
> formatting and superseding this series. I'm very sorry for the confusion.
>
> Resent on the 19th Aug.:
> https://patchwork.ozlabs.org/project/uboot/list/?series=314524
>
> No change apart from the formatting of the commit messages.

Probably should have been a v2 instead of a resend IMO.

> >> Signed-off-by: Antoine Mazeas <antoine@karthanis.net>
> >
> > Reviewed-by: Peter Robinson <pbrobinson@gmail.com>
> > Tested-by: Peter Robinson <pbrobinson@gmail.com>
> >
> > Tested on the RPi400 and a couple of different RPi4s
> >
> >> ---
> >>   board/raspberrypi/rpi/rpi.c | 3 +++
> >>   1 file changed, 3 insertions(+)
> >>
> >> diff --git a/board/raspberrypi/rpi/rpi.c b/board/raspberrypi/rpi/rpi.c
> >> index 28b6f52506..793fd1aa30 100644
> >> --- a/board/raspberrypi/rpi/rpi.c
> >> +++ b/board/raspberrypi/rpi/rpi.c
> >> @@ -548,6 +548,9 @@ void  update_fdt_from_fw(void *fdt, void *fw_fdt)
> >>
> >>          /* kernel address randomisation seed as provided by the firmware */
> >>          copy_property(fdt, fw_fdt, "/chosen", "kaslr-seed");
> >> +
> >> +       /* address of the PHY device as provided by the firmware  */
> >> +       copy_property(fdt, fw_fdt, "ethernet0/mdio@e14/ethernet-phy@1", "reg");
> >>   }
> >>
> >>   int ft_board_setup(void *blob, struct bd_info *bd)
> >> --
> >> 2.37.1
> >>

Re: [PATCH 1/2] rpi: Copy properties from firmware dtb to the loaded dtb

[Peter Robinson]

On Mon, Sep 5, 2022 at 8:11 PM Antoine Mazeas <antoine@karthanis.net> wrote:
>
> Sorry following up on your last comment, what specific issues are you
> referring to on the rev 1.3+ pi 4s ? It may be worth hunting them down,
> although I may lack access to such boards.

There was slight changes in the never rev of the SoC that affects some
things, there's various threads about it around the place and how to
address it. The Pi firmware live patches the DT basically.

> Le 05/09/2022 à 15:41, Peter Robinson a écrit :
> > Tested on RPi400 and it solves the issues with the kernel DT I've seen
> > plus some RPi4s although no the rev 1.3+ devices that also have the
> > newer SoC rev that's the same in the rpi400

Re: [PATCH 1/2] rpi: Copy properties from firmware dtb to the loaded dtb

[Peter Robinson]

Hi Antoine,

> >> The RPI firmware adjusts several property values in the dtb it passes
> >> to u-boot depending on the board/SoC revision. Inherit some of these
> >> when u-boot loads a dtb itself. Specificaly copy:
> >>
> >> * /model: The firmware provides a more specific string
> >> * /memreserve: The firmware defines a reserved range, better keep it
> >
> > Is this the CMA range or a different one? If so this makes sense.
>
> This a different range than that of the CMA (which itself is defined at
> /reserved-memory/linux,cma): it's a reserved memory range for the
> VideoCore module on the SoC. In the case of the rpi 400 (and sister
> boards like 4B based on the same chip), the dummy value in the DTB is
> patched by the firmware to a dynamic value set in config.txt; absent
> this config, the default amount is 76 MiBs (see: datasheet
> https://datasheets.raspberrypi.com/bcm2711/bcm2711-peripherals.pdf and
> rpi config reference
> https://www.raspberrypi.com/documentation/computers/config_txt.html#memory-options).
> I can see this happening on my board, where looking at the device tree
> on a running system:
>
> memreserve = <0x3b400000 0x4c00000>; // 0x4c00000 == 76 MiBs
>
> Note the start of the range is also patched in. Given the dynamic nature
> of this setting on at least bcm2711 rpi boards, I think this is worth
> carrying over.

The gpu_mem is used by the old firmware based closed source video
driver, the old version of the camera driver and a few other things.
If those aren't used it's generally recommended to reduce it as a low
as possible on the rpi4 if you're using the upstream kernel drivers
etc. although I do agree it makes sense to reserve it.

Given the newer open driver, which is now the default for rpi4 even in
Raspian, uses CMA for it's memory I think it also makes sense to pass
through the the CMA setting if set as well.

> >> * emmc2bus and pcie0 dma-ranges: The C0T revision of the bcm2711 Soc (as
> >>    present on rpi 400 and some rpi 4B boards) has different values for
> >>    these then the B0T revision. So these need to be adjusted to boot on
> >>    these boards
> >> * blconfig: The firmware defines the memory area where the blconfig
> >>    stored. Copy those over so it can be enabled.
> >> * /chosen/kaslr-seed: The firmware generates a kaslr seed, take advantage
> >>    of that.
> >
> > U-Boot has a rpi4 iproc_rng200 driver for this and provides it via the
> > UEFI random seed as well, if you're booting using UEFI that takes
> > precedence so providing this might not be useful but also it doesn't
> > matter much.
> >
> >> Signed-off-by: Sjoerd Simons <sjoerd@collabora.com>
> >
> > Reviewed-by: Peter Robinson <pbrobinson@gmail.com>
> > Tested-by: Peter Robinson <pbrobinson@gmail.com>
> >
> > Tested on RPi400 and it solves the issues with the kernel DT I've seen
> > plus some RPi4s although no the rev 1.3+ devices that also have the
> > newer SoC rev that's the same in the rpi400
> >
> >> ---
> >>   board/raspberrypi/rpi/rpi.c | 48 +++++++++++++++++++++++++++++++++++++
> >>   1 file changed, 48 insertions(+)
> >>
> >> diff --git a/board/raspberrypi/rpi/rpi.c b/board/raspberrypi/rpi/rpi.c
> >> index 17b8108cc8..28b6f52506 100644
> >> --- a/board/raspberrypi/rpi/rpi.c
> >> +++ b/board/raspberrypi/rpi/rpi.c
> >> @@ -504,10 +504,58 @@ void *board_fdt_blob_setup(int *err)
> >>          return (void *)fw_dtb_pointer;
> >>   }
> >>
> >> +int copy_property(void *dst, void *src, char *path, char *property)
> >> +{
> >> +       int dst_offset, src_offset;
> >> +       const fdt32_t *prop;
> >> +       int len;
> >> +
> >> +       src_offset = fdt_path_offset(src, path);
> >> +       dst_offset = fdt_path_offset(dst, path);
> >> +
> >> +       if (src_offset < 0 || dst_offset < 0)
> >> +               return -1;
> >> +
> >> +       prop = fdt_getprop(src, src_offset, property, &len);
> >> +       if (!prop)
> >> +               return -1;
> >> +
> >> +       return fdt_setprop(dst, dst_offset, property, prop, len);
> >> +}
> >> +
> >> +/* Copy tweaks from the firmware dtb to the loaded dtb */
> >> +void  update_fdt_from_fw(void *fdt, void *fw_fdt)
> >> +{
> >> +       /* Using dtb from firmware directly; leave it alone */
> >> +       if (fdt == fw_fdt)
> >> +               return;
> >> +
> >> +       /* The firmware provides a more precie model; so copy that */
> >> +       copy_property(fdt, fw_fdt, "/", "model");
> >> +
> >> +       /* memory reserve as suggested by the firmware */
> >> +       copy_property(fdt, fw_fdt, "/", "memreserve");
> >> +
> >> +       /* Adjust dma-ranges for the SD card and PCI bus as they can depend on
> >> +        * the SoC revision
> >> +        */
> >> +       copy_property(fdt, fw_fdt, "emmc2bus", "dma-ranges");
> >> +       copy_property(fdt, fw_fdt, "pcie0", "dma-ranges");
> >> +
> >> +       /* Bootloader configuration template exposes as nvmem */
> >> +       if (copy_property(fdt, fw_fdt, "blconfig", "reg") == 0)
> >> +               copy_property(fdt, fw_fdt, "blconfig", "status");
> >> +
> >> +       /* kernel address randomisation seed as provided by the firmware */
> >> +       copy_property(fdt, fw_fdt, "/chosen", "kaslr-seed");
> >> +}
> >> +
> >>   int ft_board_setup(void *blob, struct bd_info *bd)
> >>   {
> >>          int node;
> >>
> >> +       update_fdt_from_fw(blob, (void *)fw_dtb_pointer);
> >> +
> >>          node = fdt_node_offset_by_compatible(blob, -1, "simple-framebuffer");
> >>          if (node < 0)
> >>                  fdt_simplefb_add_node(blob);
> >> --
> >> 2.37.1
> >>