[PATCH] rpi: always set fdt_addr with firmware-provided FDT address
Raspberry firmware prepares the FDT blob in memory at an address that depends on both the memory size and the blob size [1]. After commit ade243a211d6 ("rpi: passthrough of the firmware provided FDT blob") this FDT is passed to kernel through fdt_addr environment variable, handled in set_fdt_addr() function in board file.
When u-boot environment is persistently saved, if a change happens in loaded FDT (e.g. for a new overlay applied), firmware produces a FDT address different from the saved one, but u-boot still use the saved one because set_fdt_addr() function does not overwrite the fdt_addr variable. So, for example, if there is a script that uses fdt commands for e.g. manipulate the bootargs, boot hangs with error
libfdt fdt_check_header(): FDT_ERR_BADMAGIC
Removing the fdt_addr variable in saved environment allows to boot.
With this patch set_fdt_addr() function always overwrite fdt_addr value.
[1] https://www.raspberrypi.org/forums//viewtopic.php?f=107&t=134018
Signed-off-by: Mauro Salvini m.salvini@koansoftware.com Cc: Cédric Schieli cschieli@gmail.com Cc: Matthias Brugger mbrugger@suse.com --- board/raspberrypi/rpi/rpi.c | 3 --- 1 file changed, 3 deletions(-)
diff --git a/board/raspberrypi/rpi/rpi.c b/board/raspberrypi/rpi/rpi.c index df52a4689f..611013471e 100644 --- a/board/raspberrypi/rpi/rpi.c +++ b/board/raspberrypi/rpi/rpi.c @@ -318,9 +318,6 @@ static void set_fdtfile(void) */ static void set_fdt_addr(void) { - if (env_get("fdt_addr")) - return; - if (fdt_magic(fw_dtb_pointer) != FDT_MAGIC) return;
On 12/05/21 14:39, Mauro Salvini wrote:
Raspberry firmware prepares the FDT blob in memory at an address that depends on both the memory size and the blob size [1]. After commit ade243a211d6 ("rpi: passthrough of the firmware provided FDT blob") this FDT is passed to kernel through fdt_addr environment variable, handled in set_fdt_addr() function in board file.
When u-boot environment is persistently saved, if a change happens in loaded FDT (e.g. for a new overlay applied), firmware produces a FDT address different from the saved one, but u-boot still use the saved one because set_fdt_addr() function does not overwrite the fdt_addr variable. So, for example, if there is a script that uses fdt commands for e.g. manipulate the bootargs, boot hangs with error
libfdt fdt_check_header(): FDT_ERR_BADMAGIC
Removing the fdt_addr variable in saved environment allows to boot.
With this patch set_fdt_addr() function always overwrite fdt_addr value.
[1] https://www.raspberrypi.org/forums//viewtopic.php?f=107&t=134018
Signed-off-by: Mauro Salvini m.salvini@koansoftware.com Cc: Cédric Schieli cschieli@gmail.com Cc: Matthias Brugger mbrugger@suse.com
board/raspberrypi/rpi/rpi.c | 3 --- 1 file changed, 3 deletions(-)
diff --git a/board/raspberrypi/rpi/rpi.c b/board/raspberrypi/rpi/rpi.c index df52a4689f..611013471e 100644 --- a/board/raspberrypi/rpi/rpi.c +++ b/board/raspberrypi/rpi/rpi.c @@ -318,9 +318,6 @@ static void set_fdtfile(void) */ static void set_fdt_addr(void) {
- if (env_get("fdt_addr"))
return;- if (fdt_magic(fw_dtb_pointer) != FDT_MAGIC) return;
Hi all,
kind ping.
Regards
Hi Mauro,
On 07/06/2021 11:27, Mauro Salvini wrote:
On 12/05/21 14:39, Mauro Salvini wrote:
Raspberry firmware prepares the FDT blob in memory at an address that depends on both the memory size and the blob size [1]. After commit ade243a211d6 ("rpi: passthrough of the firmware provided FDT blob") this FDT is passed to kernel through fdt_addr environment variable, handled in set_fdt_addr() function in board file.
When u-boot environment is persistently saved, if a change happens in loaded FDT (e.g. for a new overlay applied), firmware produces a FDT address different from the saved one, but u-boot still use the saved one because set_fdt_addr() function does not overwrite the fdt_addr variable. So, for example, if there is a script that uses fdt commands for e.g. manipulate the bootargs, boot hangs with error
libfdt fdt_check_header(): FDT_ERR_BADMAGIC
Removing the fdt_addr variable in saved environment allows to boot.
With this patch set_fdt_addr() function always overwrite fdt_addr value.
[1] https://www.raspberrypi.org/forums//viewtopic.php?f=107&t=134018
First of all sorry for the very late reply. I'm hesitant to apply this patch, basically because it can break other setups where people load a custom DTB to fdt_addr.
I wonder why you can't erase fdt_addr from your persistent storage. There is a command called eraseenv that should to the job.
Regards, Matthias
Signed-off-by: Mauro Salvini m.salvini@koansoftware.com Cc: Cédric Schieli cschieli@gmail.com Cc: Matthias Brugger mbrugger@suse.com
board/raspberrypi/rpi/rpi.c | 3 --- 1 file changed, 3 deletions(-)
diff --git a/board/raspberrypi/rpi/rpi.c b/board/raspberrypi/rpi/rpi.c index df52a4689f..611013471e 100644 --- a/board/raspberrypi/rpi/rpi.c +++ b/board/raspberrypi/rpi/rpi.c @@ -318,9 +318,6 @@ static void set_fdtfile(void) */ static void set_fdt_addr(void) { - if (env_get("fdt_addr")) - return;
if (fdt_magic(fw_dtb_pointer) != FDT_MAGIC) return;
Hi all,
kind ping.
Regards
Hi Matthias
On 15/09/21 13:16, mbrugger at suse.com (Matthias Brugger) wrote:
Hi Mauro,
On 07/06/2021 11:27, Mauro Salvini wrote:
On 12/05/21 14:39, Mauro Salvini wrote:
Raspberry firmware prepares the FDT blob in memory at an address that depends on both the memory size and the blob size [1]. After commit ade243a211d6 ("rpi: passthrough of the firmware provided FDT blob") this FDT is passed to kernel through fdt_addr environment variable, handled in set_fdt_addr() function in board file.
When u-boot environment is persistently saved, if a change happens in loaded FDT (e.g. for a new overlay applied), firmware produces a FDT address different from the saved one, but u-boot still use the saved one because set_fdt_addr() function does not overwrite the fdt_addr variable. So, for example, if there is a script that uses fdt commands for e.g. manipulate the bootargs, boot hangs with error
libfdt fdt_check_header(): FDT_ERR_BADMAGIC
Removing the fdt_addr variable in saved environment allows to boot.
With this patch set_fdt_addr() function always overwrite fdt_addr value.
[1] https://www.raspberrypi.org/forums//viewtopic.php?f=107&t=134018
First of all sorry for the very late reply. I'm hesitant to apply this patch, basically because it can break other setups where people load a custom DTB to fdt_addr.
I wonder why you can't erase fdt_addr from your persistent storage. There is a command called eraseenv that should to the job.
Sorry me too for the late reply.
So your suggestion is to erase the fdt_addr variable from the environment each time one needs to "refresh" it (one example could be the situation that I ponted out).
Yes, this could be the solution, but the need to delete the fdt_addr variable when e.g. one changes the dtb loaded by rpi firmware should be documented somewhere.
Thanks, regards Mauro
Regards, Matthias
Signed-off-by: Mauro Salvini <m.salvini at koansoftware.com> Cc: C?dric Schieli <cschieli at gmail.com> Cc: Matthias Brugger <mbrugger at suse.com>
? board/raspberrypi/rpi/rpi.c | 3 --- ? 1 file changed, 3 deletions(-)
diff --git a/board/raspberrypi/rpi/rpi.c b/board/raspberrypi/rpi/rpi.c index df52a4689f..611013471e 100644 --- a/board/raspberrypi/rpi/rpi.c +++ b/board/raspberrypi/rpi/rpi.c @@ -318,9 +318,6 @@ static void set_fdtfile(void) ?? */ ? static void set_fdt_addr(void) ? { -??? if (env_get("fdt_addr")) -??????? return;
????? if (fdt_magic(fw_dtb_pointer) != FDT_MAGIC) ????????? return;
Hi all,
kind ping.
Regards
Hi Mauro,
On 29/09/2021 12:14, Mauro Salvini wrote:
Hi Matthias
On 15/09/21 13:16, mbrugger at suse.com (Matthias Brugger) wrote:
Hi Mauro,
On 07/06/2021 11:27, Mauro Salvini wrote:
On 12/05/21 14:39, Mauro Salvini wrote:
Raspberry firmware prepares the FDT blob in memory at an address that depends on both the memory size and the blob size [1]. After commit ade243a211d6 ("rpi: passthrough of the firmware provided FDT blob") this FDT is passed to kernel through fdt_addr environment variable, handled in set_fdt_addr() function in board file.
When u-boot environment is persistently saved, if a change happens in loaded FDT (e.g. for a new overlay applied), firmware produces a FDT address different from the saved one, but u-boot still use the saved one because set_fdt_addr() function does not overwrite the fdt_addr variable. So, for example, if there is a script that uses fdt commands for e.g. manipulate the bootargs, boot hangs with error
libfdt fdt_check_header(): FDT_ERR_BADMAGIC
Removing the fdt_addr variable in saved environment allows to boot.
With this patch set_fdt_addr() function always overwrite fdt_addr value.
[1] https://www.raspberrypi.org/forums//viewtopic.php?f=107&t=134018
First of all sorry for the very late reply. I'm hesitant to apply this patch, basically because it can break other setups where people load a custom DTB to fdt_addr.
I wonder why you can't erase fdt_addr from your persistent storage. There is a command called eraseenv that should to the job.
Sorry me too for the late reply.
So your suggestion is to erase the fdt_addr variable from the environment each time one needs to "refresh" it (one example could be the situation that I ponted out).
Yes, this could be the solution, but the need to delete the fdt_addr variable when e.g. one changes the dtb loaded by rpi firmware should be documented somewhere.
Hm, maybe I didn't understand the problem. My understanding is, that when you save the environment with saveenv, you also save the fdt_addr. And that's a problem because if you add a overlay later, the fdt_addr changed, which will not be reflected. So my question was if you couldn't just delete the fdt_addr variable from you saved environment so that when lateron you load overlays, you won't hit the problem.
My understanding was that you are setting a custom environment for your boards, but later your customers might add a overlay via e.g. config.txt and that will break booting the system.
But from your response it seems thats not what you are experiencing. Or do you change the DTB loaded from FW in the U-Boot shell?
Regards, Matthias
Thanks, regards Mauro
Regards, Matthias
Signed-off-by: Mauro Salvini <m.salvini at koansoftware.com> Cc: C?dric Schieli <cschieli at gmail.com> Cc: Matthias Brugger <mbrugger at suse.com>
? board/raspberrypi/rpi/rpi.c | 3 --- ? 1 file changed, 3 deletions(-)
diff --git a/board/raspberrypi/rpi/rpi.c b/board/raspberrypi/rpi/rpi.c index df52a4689f..611013471e 100644 --- a/board/raspberrypi/rpi/rpi.c +++ b/board/raspberrypi/rpi/rpi.c @@ -318,9 +318,6 @@ static void set_fdtfile(void) ?? */ ? static void set_fdt_addr(void) ? { -??? if (env_get("fdt_addr")) -??????? return;
????? if (fdt_magic(fw_dtb_pointer) != FDT_MAGIC) ????????? return;
Hi all,
kind ping.
Regards
Hi Matthias,
On 29/09/21 13:41, Matthias Brugger wrote:
Hi Mauro,
On 29/09/2021 12:14, Mauro Salvini wrote:
Hi Matthias
On 15/09/21 13:16, mbrugger at suse.com (Matthias Brugger) wrote:
Hi Mauro,
On 07/06/2021 11:27, Mauro Salvini wrote:
On 12/05/21 14:39, Mauro Salvini wrote:
Raspberry firmware prepares the FDT blob in memory at an address that depends on both the memory size and the blob size [1]. After commit ade243a211d6 ("rpi: passthrough of the firmware provided FDT blob") this FDT is passed to kernel through fdt_addr environment variable, handled in set_fdt_addr() function in board file.
When u-boot environment is persistently saved, if a change happens in loaded FDT (e.g. for a new overlay applied), firmware produces a FDT address different from the saved one, but u-boot still use the saved one because set_fdt_addr() function does not overwrite the fdt_addr variable. So, for example, if there is a script that uses fdt commands for e.g. manipulate the bootargs, boot hangs with error
libfdt fdt_check_header(): FDT_ERR_BADMAGIC
Removing the fdt_addr variable in saved environment allows to boot.
With this patch set_fdt_addr() function always overwrite fdt_addr value.
[1] https://www.raspberrypi.org/forums//viewtopic.php?f=107&t=134018
First of all sorry for the very late reply. I'm hesitant to apply this patch, basically because it can break other setups where people load a custom DTB to fdt_addr.
I wonder why you can't erase fdt_addr from your persistent storage. There is a command called eraseenv that should to the job.
Sorry me too for the late reply.
So your suggestion is to erase the fdt_addr variable from the environment each time one needs to "refresh" it (one example could be the situation that I ponted out).
Yes, this could be the solution, but the need to delete the fdt_addr variable when e.g. one changes the dtb loaded by rpi firmware should be documented somewhere.
Hm, maybe I didn't understand the problem. My understanding is, that when you save the environment with saveenv, you also save the fdt_addr. And that's a problem because if you add a overlay later, the fdt_addr changed, which will not be reflected. So my question was if you couldn't just delete the fdt_addr variable from you saved environment so that when lateron you load overlays, you won't hit the problem. > My understanding was that you are setting a custom environment for your boards, but later your customers might add a overlay via e.g. config.txt and that will break booting the system.
But from your response it seems thats not what you are experiencing. Or do you change the DTB loaded from FW in the U-Boot shell?
Maybe I wasn't too clear in my explanation ;-)
At every boot, u-boot executes set_fdt_addr() function. At the very first boot, if nobody has changed the default u-boot environment built in u-boot, adding a custom fdt_addr variable, this function saves the fdt_addr variable in persistent u-boot env. Variable contains the address where RPI firmware has loaded the dtb, passed to u-boot by RPI firmware. This variable is not changed anymore by u-boot itself (to change it, you have to use u-boot cli). If you still use the same dtb, loaded by the RPI firmware, it's not a problem, because the fdt address computed by RPI firmware is always the same at every boot, and equal to the one saved in persistent env. If you delete the variable from saved env, at next boot it will be re-created in persistent env, with the value from RPI firmware.
Suppose that after some time one changes the config.txt and adds an overlay.
On the next boot, RPI firmware applies the overlay, and the new fdt address could be different from the one computed until last boot (why it changes, I don't know). But set_fdt_addr() function does not update the value in env, because fdt_addr is set yet. Then, u-boot uses the fdt from a wrong address, and, if it executes a script to manupulate e.g. bootargs, you got the error.
Applying the patch, the variable will be saved at every boot, the the value saved is always the right one. Conversely, as you pointed out, a fdt_addr variable set in the persistent environment by the user will be overwritten.
Then, the best option should be to write somewhere in the documentation that, if one loads the dtb using RPI firmware instead of u-boot, after changing config.txt or the dtb itself, the fdt_addr variable in u-boot environment must be deleted.
Feel free to require more clarifications if needed.
Thank you
Mauro
Regards, Matthias
Thanks, regards Mauro
Regards, Matthias
Signed-off-by: Mauro Salvini <m.salvini at koansoftware.com> Cc: C?dric Schieli <cschieli at gmail.com> Cc: Matthias Brugger <mbrugger at suse.com>
? board/raspberrypi/rpi/rpi.c | 3 --- ? 1 file changed, 3 deletions(-)
diff --git a/board/raspberrypi/rpi/rpi.c b/board/raspberrypi/rpi/rpi.c index df52a4689f..611013471e 100644 --- a/board/raspberrypi/rpi/rpi.c +++ b/board/raspberrypi/rpi/rpi.c @@ -318,9 +318,6 @@ static void set_fdtfile(void) ?? */ ? static void set_fdt_addr(void) ? { -??? if (env_get("fdt_addr")) -??????? return;
????? if (fdt_magic(fw_dtb_pointer) != FDT_MAGIC) ????????? return;
Hi all,
kind ping.
Regards
On 29/09/2021 14:19, Mauro Salvini wrote:
Hi Matthias,
On 29/09/21 13:41, Matthias Brugger wrote:
Hi Mauro,
On 29/09/2021 12:14, Mauro Salvini wrote:
Hi Matthias
On 15/09/21 13:16, mbrugger at suse.com (Matthias Brugger) wrote:
Hi Mauro,
On 07/06/2021 11:27, Mauro Salvini wrote:
On 12/05/21 14:39, Mauro Salvini wrote:
Raspberry firmware prepares the FDT blob in memory at an address that depends on both the memory size and the blob size [1]. After commit ade243a211d6 ("rpi: passthrough of the firmware provided FDT blob") this FDT is passed to kernel through fdt_addr environment variable, handled in set_fdt_addr() function in board file.
When u-boot environment is persistently saved, if a change happens in loaded FDT (e.g. for a new overlay applied), firmware produces a FDT address different from the saved one, but u-boot still use the saved one because set_fdt_addr() function does not overwrite the fdt_addr variable. So, for example, if there is a script that uses fdt commands for e.g. manipulate the bootargs, boot hangs with error
libfdt fdt_check_header(): FDT_ERR_BADMAGIC
Removing the fdt_addr variable in saved environment allows to boot.
With this patch set_fdt_addr() function always overwrite fdt_addr value.
[1] https://www.raspberrypi.org/forums//viewtopic.php?f=107&t=134018
First of all sorry for the very late reply. I'm hesitant to apply this patch, basically because it can break other setups where people load a custom DTB to fdt_addr.
I wonder why you can't erase fdt_addr from your persistent storage. There is a command called eraseenv that should to the job.
Sorry me too for the late reply.
So your suggestion is to erase the fdt_addr variable from the environment each time one needs to "refresh" it (one example could be the situation that I ponted out).
Yes, this could be the solution, but the need to delete the fdt_addr variable when e.g. one changes the dtb loaded by rpi firmware should be documented somewhere.
Hm, maybe I didn't understand the problem. My understanding is, that when you save the environment with saveenv, you also save the fdt_addr. And that's a problem because if you add a overlay later, the fdt_addr changed, which will not be reflected. So my question was if you couldn't just delete the fdt_addr variable from you saved environment so that when lateron you load overlays, you won't hit the problem. > My understanding was that you are setting a custom environment for your boards, but later your customers might add a overlay via e.g. config.txt and that will break booting the system.
But from your response it seems thats not what you are experiencing. Or do you change the DTB loaded from FW in the U-Boot shell?
Maybe I wasn't too clear in my explanation ;-)
At every boot, u-boot executes set_fdt_addr() function. At the very first boot, if nobody has changed the default u-boot environment built in u-boot, adding a custom fdt_addr variable, this function saves the fdt_addr variable in
Which function are we talking about? Adding a custom fdt_addr can be done via the CLI or by adding that to the U-Boot sources (include/configs/rpi.h) but not through a 'function'.
Do you mean that in some script you made saveenv is called? I used overlays in RPi and never had that problem.
Actually I'm a bit puzzled about the problem. Can you give me a step by step reproducer, starting with which config I should use to compile U-Boot?
Regards, Matthias
persistent u-boot env. Variable contains the address where RPI firmware has loaded the dtb, passed to u-boot by RPI firmware. This variable is not changed anymore by u-boot itself (to change it, you have to use u-boot cli). If you still use the same dtb, loaded by the RPI firmware, it's not a problem, because the fdt address computed by RPI firmware is always the same at every boot, and equal to the one saved in persistent env. If you delete the variable from saved env, at next boot it will be re-created in persistent env, with the value from RPI firmware.
Suppose that after some time one changes the config.txt and adds an overlay.
On the next boot, RPI firmware applies the overlay, and the new fdt address could be different from the one computed until last boot (why it changes, I don't know). But set_fdt_addr() function does not update the value in env, because fdt_addr is set yet. Then, u-boot uses the fdt from a wrong address, and, if it executes a script to manupulate e.g. bootargs, you got the error.
Applying the patch, the variable will be saved at every boot, the the value saved is always the right one. Conversely, as you pointed out, a fdt_addr variable set in the persistent environment by the user will be overwritten.
Then, the best option should be to write somewhere in the documentation that, if one loads the dtb using RPI firmware instead of u-boot, after changing config.txt or the dtb itself, the fdt_addr variable in u-boot environment must be deleted.
Feel free to require more clarifications if needed.
Thank you
Mauro
Regards, Matthias
Thanks, regards Mauro
Regards, Matthias
Signed-off-by: Mauro Salvini <m.salvini at koansoftware.com> Cc: C?dric Schieli <cschieli at gmail.com> Cc: Matthias Brugger <mbrugger at suse.com>
? board/raspberrypi/rpi/rpi.c | 3 --- ? 1 file changed, 3 deletions(-)
diff --git a/board/raspberrypi/rpi/rpi.c b/board/raspberrypi/rpi/rpi.c index df52a4689f..611013471e 100644 --- a/board/raspberrypi/rpi/rpi.c +++ b/board/raspberrypi/rpi/rpi.c @@ -318,9 +318,6 @@ static void set_fdtfile(void) ?? */ ? static void set_fdt_addr(void) ? { -??? if (env_get("fdt_addr")) -??????? return;
????? if (fdt_magic(fw_dtb_pointer) != FDT_MAGIC) ????????? return;
Hi all,
kind ping.
Regards
On Wed, Sep 29, 2021 at 1:49 PM Matthias Brugger mbrugger@suse.com wrote:
On 29/09/2021 14:19, Mauro Salvini wrote:
Hi Matthias,
On 29/09/21 13:41, Matthias Brugger wrote:
Hi Mauro,
On 29/09/2021 12:14, Mauro Salvini wrote:
Hi Matthias
On 15/09/21 13:16, mbrugger at suse.com (Matthias Brugger) wrote:
Hi Mauro,
On 07/06/2021 11:27, Mauro Salvini wrote:
On 12/05/21 14:39, Mauro Salvini wrote: > Raspberry firmware prepares the FDT blob in memory at an address > that depends on both the memory size and the blob size [1]. > After commit ade243a211d6 ("rpi: passthrough of the firmware provided FDT > blob") this FDT is passed to kernel through fdt_addr environment variable, > handled in set_fdt_addr() function in board file. > > When u-boot environment is persistently saved, if a change happens > in loaded FDT (e.g. for a new overlay applied), firmware produces a FDT > address different from the saved one, but u-boot still use the saved > one because set_fdt_addr() function does not overwrite the fdt_addr > variable. So, for example, if there is a script that uses fdt commands for > e.g. manipulate the bootargs, boot hangs with error > > libfdt fdt_check_header(): FDT_ERR_BADMAGIC > > Removing the fdt_addr variable in saved environment allows to boot. > > With this patch set_fdt_addr() function always overwrite fdt_addr value. > > [1] https://www.raspberrypi.org/forums//viewtopic.php?f=107&t=134018 >
First of all sorry for the very late reply. I'm hesitant to apply this patch, basically because it can break other setups where people load a custom DTB to fdt_addr.
I wonder why you can't erase fdt_addr from your persistent storage. There is a command called eraseenv that should to the job.
Sorry me too for the late reply.
So your suggestion is to erase the fdt_addr variable from the environment each time one needs to "refresh" it (one example could be the situation that I ponted out).
Yes, this could be the solution, but the need to delete the fdt_addr variable when e.g. one changes the dtb loaded by rpi firmware should be documented somewhere.
Hm, maybe I didn't understand the problem. My understanding is, that when you save the environment with saveenv, you also save the fdt_addr. And that's a problem because if you add a overlay later, the fdt_addr changed, which will not be reflected. So my question was if you couldn't just delete the fdt_addr variable from you saved environment so that when lateron you load overlays, you won't hit the problem. > My understanding was that you are setting a custom environment for your boards, but later your customers might add a overlay via e.g. config.txt and that will break booting the system.
But from your response it seems thats not what you are experiencing. Or do you change the DTB loaded from FW in the U-Boot shell?
Maybe I wasn't too clear in my explanation ;-)
At every boot, u-boot executes set_fdt_addr() function. At the very first boot, if nobody has changed the default u-boot environment built in u-boot, adding a custom fdt_addr variable, this function saves the fdt_addr variable in
Which function are we talking about? Adding a custom fdt_addr can be done via the CLI or by adding that to the U-Boot sources (include/configs/rpi.h) but not through a 'function'.
Do you mean that in some script you made saveenv is called? I used overlays in RPi and never had that problem.
Actually I'm a bit puzzled about the problem. Can you give me a step by step reproducer, starting with which config I should use to compile U-Boot?
Yes, this issue only happens if you save the environment at least once, as then on following boots it won't set the address based on what the firmware uses, but instead restore the value from the saved environment, which can be wrong.
I noticed the same when moving one sdcard between boards, and I was only able to get it to boot correctly after removing the saved environment.
Cheers,
On 29/09/2021 23:05, Ricardo Salveti wrote:
On Wed, Sep 29, 2021 at 1:49 PM Matthias Brugger mbrugger@suse.com wrote:
On 29/09/2021 14:19, Mauro Salvini wrote:
Hi Matthias,
On 29/09/21 13:41, Matthias Brugger wrote:
Hi Mauro,
On 29/09/2021 12:14, Mauro Salvini wrote:
Hi Matthias
On 15/09/21 13:16, mbrugger at suse.com (Matthias Brugger) wrote:
Hi Mauro,
On 07/06/2021 11:27, Mauro Salvini wrote: > On 12/05/21 14:39, Mauro Salvini wrote: >> Raspberry firmware prepares the FDT blob in memory at an address >> that depends on both the memory size and the blob size [1]. >> After commit ade243a211d6 ("rpi: passthrough of the firmware provided FDT >> blob") this FDT is passed to kernel through fdt_addr environment variable, >> handled in set_fdt_addr() function in board file. >> >> When u-boot environment is persistently saved, if a change happens >> in loaded FDT (e.g. for a new overlay applied), firmware produces a FDT >> address different from the saved one, but u-boot still use the saved >> one because set_fdt_addr() function does not overwrite the fdt_addr >> variable. So, for example, if there is a script that uses fdt commands for >> e.g. manipulate the bootargs, boot hangs with error >> >> libfdt fdt_check_header(): FDT_ERR_BADMAGIC >> >> Removing the fdt_addr variable in saved environment allows to boot. >> >> With this patch set_fdt_addr() function always overwrite fdt_addr value. >> >> [1] https://www.raspberrypi.org/forums//viewtopic.php?f=107&t=134018 >>
First of all sorry for the very late reply. I'm hesitant to apply this patch, basically because it can break other setups where people load a custom DTB to fdt_addr.
I wonder why you can't erase fdt_addr from your persistent storage. There is a command called eraseenv that should to the job.
Sorry me too for the late reply.
So your suggestion is to erase the fdt_addr variable from the environment each time one needs to "refresh" it (one example could be the situation that I ponted out).
Yes, this could be the solution, but the need to delete the fdt_addr variable when e.g. one changes the dtb loaded by rpi firmware should be documented somewhere.
Hm, maybe I didn't understand the problem. My understanding is, that when you save the environment with saveenv, you also save the fdt_addr. And that's a problem because if you add a overlay later, the fdt_addr changed, which will not be reflected. So my question was if you couldn't just delete the fdt_addr variable from you saved environment so that when lateron you load overlays, you won't hit the problem. > My understanding was that you are setting a custom environment for your boards, but later your customers might add a overlay via e.g. config.txt and that will break booting the system.
But from your response it seems thats not what you are experiencing. Or do you change the DTB loaded from FW in the U-Boot shell?
Maybe I wasn't too clear in my explanation ;-)
At every boot, u-boot executes set_fdt_addr() function. At the very first boot, if nobody has changed the default u-boot environment built in u-boot, adding a custom fdt_addr variable, this function saves the fdt_addr variable in
Which function are we talking about? Adding a custom fdt_addr can be done via the CLI or by adding that to the U-Boot sources (include/configs/rpi.h) but not through a 'function'.
Do you mean that in some script you made saveenv is called? I used overlays in RPi and never had that problem.
Actually I'm a bit puzzled about the problem. Can you give me a step by step reproducer, starting with which config I should use to compile U-Boot?
Yes, this issue only happens if you save the environment at least once, as then on following boots it won't set the address based on what the firmware uses, but instead restore the value from the saved environment, which can be wrong.
So can't we just delete the environment variable before saving the environment? Something like "env delete fdt_addr; saveenv" ?
Regards, Matthias
I noticed the same when moving one sdcard between boards, and I was only able to get it to boot correctly after removing the saved environment.
Cheers,
On Thu, Sep 30, 2021 at 12:12 AM Matthias Brugger mbrugger@suse.com wrote:
On 29/09/2021 23:05, Ricardo Salveti wrote:
On Wed, Sep 29, 2021 at 1:49 PM Matthias Brugger mbrugger@suse.com wrote:
On 29/09/2021 14:19, Mauro Salvini wrote:
Hi Matthias,
On 29/09/21 13:41, Matthias Brugger wrote:
Hi Mauro,
On 29/09/2021 12:14, Mauro Salvini wrote:
Hi Matthias
On 15/09/21 13:16, mbrugger at suse.com (Matthias Brugger) wrote: > Hi Mauro, > > On 07/06/2021 11:27, Mauro Salvini wrote: >> On 12/05/21 14:39, Mauro Salvini wrote: >>> Raspberry firmware prepares the FDT blob in memory at an address >>> that depends on both the memory size and the blob size [1]. >>> After commit ade243a211d6 ("rpi: passthrough of the firmware provided FDT >>> blob") this FDT is passed to kernel through fdt_addr environment variable, >>> handled in set_fdt_addr() function in board file. >>> >>> When u-boot environment is persistently saved, if a change happens >>> in loaded FDT (e.g. for a new overlay applied), firmware produces a FDT >>> address different from the saved one, but u-boot still use the saved >>> one because set_fdt_addr() function does not overwrite the fdt_addr >>> variable. So, for example, if there is a script that uses fdt commands for >>> e.g. manipulate the bootargs, boot hangs with error >>> >>> libfdt fdt_check_header(): FDT_ERR_BADMAGIC >>> >>> Removing the fdt_addr variable in saved environment allows to boot. >>> >>> With this patch set_fdt_addr() function always overwrite fdt_addr value. >>> >>> [1] https://www.raspberrypi.org/forums//viewtopic.php?f=107&t=134018 >>> > > First of all sorry for the very late reply. > I'm hesitant to apply this patch, basically because it can break other setups > where people load a custom DTB to fdt_addr. > > I wonder why you can't erase fdt_addr from your persistent storage. There is a > command called eraseenv that should to the job.
Sorry me too for the late reply.
So your suggestion is to erase the fdt_addr variable from the environment each time one needs to "refresh" it (one example could be the situation that I ponted out).
Yes, this could be the solution, but the need to delete the fdt_addr variable when e.g. one changes the dtb loaded by rpi firmware should be documented somewhere.
Hm, maybe I didn't understand the problem. My understanding is, that when you save the environment with saveenv, you also save the fdt_addr. And that's a problem because if you add a overlay later, the fdt_addr changed, which will not be reflected. So my question was if you couldn't just delete the fdt_addr variable from you saved environment so that when lateron you load overlays, you won't hit the problem. > My understanding was that you are setting a custom environment for your boards, but later your customers might add a overlay via e.g. config.txt and that will break booting the system.
But from your response it seems thats not what you are experiencing. Or do you change the DTB loaded from FW in the U-Boot shell?
Maybe I wasn't too clear in my explanation ;-)
At every boot, u-boot executes set_fdt_addr() function. At the very first boot, if nobody has changed the default u-boot environment built in u-boot, adding a custom fdt_addr variable, this function saves the fdt_addr variable in
Which function are we talking about? Adding a custom fdt_addr can be done via the CLI or by adding that to the U-Boot sources (include/configs/rpi.h) but not through a 'function'.
Do you mean that in some script you made saveenv is called? I used overlays in RPi and never had that problem.
Actually I'm a bit puzzled about the problem. Can you give me a step by step reproducer, starting with which config I should use to compile U-Boot?
Yes, this issue only happens if you save the environment at least once, as then on following boots it won't set the address based on what the firmware uses, but instead restore the value from the saved environment, which can be wrong.
So can't we just delete the environment variable before saving the environment? Something like "env delete fdt_addr; saveenv" ?
Sure, but that would be a custom logic that needs to be handled by the user, and this problem can happen with anyone doing a simple saveenv without knowing that this could be an issue.
Why not simply just trust what the firmware gives instead?
Cheers,
participants (3)
-
Matthias Brugger -
Mauro Salvini -
Ricardo Salveti