* Barebox OF-Overlay Handling
@ 2021-01-13 11:07 Marco Felsch
2021-01-13 14:07 ` Rouven Czerwinski
0 siblings, 1 reply; 4+ messages in thread
From: Marco Felsch @ 2021-01-13 11:07 UTC (permalink / raw)
To: barebox; +Cc: Michael Tretter
Hi there,
I have the following problem. My customer is using overlays for
external devices like: display, camera, etc. The current overlay support
is awesome and most of it works out of the box. There is only one
nitpick: If Barebox isn't build with CONFIG_OF_OVERLAY_LIVE enabled many
error's are printed during boot. Those error's are ignored but let the
user assume that something went really bad:
ERROR: of_resolver: __symbols__ missing from base devicetree
ERROR: of_overlay: fragment 30164b88: phandle 0xffffffff not found
ERROR: of_overlay: fragment 30164c84: phandle 0xffffffff not found
ERROR: of_overlay: fragment 3012fb08: phandle 0xffffffff not found
ERROR: of_overlay: fragment 3012fc34: phandle 0xffffffff not found
ERROR: of_overlay: fragment 3012fd60: phandle 0xffffffff not found
ERROR: of_overlay: fragment 3012fe8c: phandle 0xffffffff not found
ERROR: of_overlay: fragment 3012ffb8: phandle 0xffffffff not found
ERROR: of_overlay: fragment 301300e4: phandle 0xffffffff not found
ERROR: of_overlay: fragment 30130210: phandle 0xffffffff not found
ERROR: of_overlay: fragment 3013033c: phandle 0xffffffff not found
ERROR: of_resolver: __symbols__ missing from base devicetree
ERROR: of_overlay: fragment 30130e94: phandle 0xffffffff not found
ERROR: of_overlay: fragment 30130fc4: phandle 0xffffffff not found
ERROR: of_resolver: __symbols__ missing from base devicetree
ERROR: of_overlay: fragment 30131a14: phandle 0xffffffff not found
ERROR: of_overlay: fragment 301342d4: phandle 0xffffffff not found
The of_firmware_load_overlay() calls triggering those errors.
The error's by itself are correct and I don't wanna change them but the
context must be correct by context I mean:
- barebox-dt on fpga-platform: An FPGA platform needs a barebox
base devicetree with __symbols__ and those error are correct because
the firmware manager needs to load the firmware.
- barebox-dt on non fpga-platform: Those errors are not correct.
We don't need __symbols__ for the barebox base devicetree.
- kernel-dt on any platform: Those error's are correct if
the overlays are using phandles which should be the case most the
time.
My proposed solution would be a stub like this:
#ifdef CONFIG_OF_OVERLAY_LIVE
int of_firmware_load_overlay(struct device_node *overlay, const char *path);
#else
static inline int of_firmware_load_overlay(struct device_node *overlay, const char *path)
{
return 0;
}
#endif /* CONFIG_OF_OVERLAY_LIVE */
The disadvantage of this solution is that it can happen to end in a
non-booting device for FPGA platforms using overlays to programm the
bit stream and forget to enable CONFIG_OF_OVERLAY_LIVE because the
kernel tries to access regions not existing.
I've discussed this with Michael in private but we didn't came to a
conclusion. Therefore I'm asking here any input would be helpfull :)
Regards,
Marco
_______________________________________________
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barebox@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/barebox
^ permalink raw reply [flat|nested] 4+ messages in thread* Re: Barebox OF-Overlay Handling 2021-01-13 11:07 Barebox OF-Overlay Handling Marco Felsch @ 2021-01-13 14:07 ` Rouven Czerwinski 2021-01-13 14:52 ` Michael Tretter 0 siblings, 1 reply; 4+ messages in thread From: Rouven Czerwinski @ 2021-01-13 14:07 UTC (permalink / raw) To: Marco Felsch, barebox; +Cc: Michael Tretter On Wed, 2021-01-13 at 12:07 +0100, Marco Felsch wrote: > Hi there, > > I have the following problem. My customer is using overlays for > external devices like: display, camera, etc. The current overlay support > is awesome and most of it works out of the box. There is only one > nitpick: If Barebox isn't build with CONFIG_OF_OVERLAY_LIVE enabled many > error's are printed during boot. Those error's are ignored but let the > user assume that something went really bad: > > ERROR: of_resolver: __symbols__ missing from base devicetree > ERROR: of_overlay: fragment 30164b88: phandle 0xffffffff not found > ERROR: of_overlay: fragment 30164c84: phandle 0xffffffff not found > ERROR: of_overlay: fragment 3012fb08: phandle 0xffffffff not found > ERROR: of_overlay: fragment 3012fc34: phandle 0xffffffff not found > ERROR: of_overlay: fragment 3012fd60: phandle 0xffffffff not found > ERROR: of_overlay: fragment 3012fe8c: phandle 0xffffffff not found > ERROR: of_overlay: fragment 3012ffb8: phandle 0xffffwfffffff not found > ERROR: of_overlay: fragment 301300e4: phandle 0xffffffff not found > ERROR: of_overlay: fragment 30130210: phandle 0xffffffff not found > ERROR: of_overlay: fragment 3013033c: phandle 0xffffffff not found > ERROR: of_resolver: __symbols__ missing from base devicetree > ERROR: of_overlay: fragment 30130e94: phandle 0xffffffff not found > ERROR: of_overlay: fragment 30130fc4: phandle 0xffffffff not found > ERROR: of_resolver: __symbols__ missing from base devicetree > ERROR: of_overlay: fragment 30131a14: phandle 0xffffffff not found > ERROR: of_overlay: fragment 301342d4: phandle 0xffffffff not found > > The of_firmware_load_overlay() calls triggering those errors. > The error's by itself are correct and I don't wanna change them but the > context must be correct by context I mean: > > - barebox-dt on fpga-platform: An FPGA platform needs a barebox > base devicetree with __symbols__ and those error are correct because > the firmware manager needs to load the firmware. > - barebox-dt on non fpga-platform: Those errors are not correct. > We don't need __symbols__ for the barebox base devicetree. I was wondering why you were getting this error even on a platform without FPGA, turns out of_firmware_load_overlay() is always called if a devicetree overlay is passed via the DT. This in itself isn't a problem, but IMO of_firmware_load_overlay() should check first whether the overlay contains the right compatible ("fpga-region") and property ("firmware-name") before doing of_resolve_phandles and of_process_overlay. This way we can skip a lot of unnecessary overlay handling if we don't end up loading a firmware. > - kernel-dt on any platform: Those error's are correct if > the overlays are using phandles which should be the case most the > time. AFAICS this should also fix this case. > My proposed solution would be a stub like this: > > #ifdef CONFIG_OF_OVERLAY_LIVE > int of_firmware_load_overlay(struct device_node *overlay, const char *path); > #else > static inline int of_firmware_load_overlay(struct device_node *overlay, const char *path) > { > return 0; > } > #endif /* CONFIG_OF_OVERLAY_LIVE */ While correct in case all firmware overlays use phandles, in theory overlays could be purely path-based, with not dependency on the __symbols__ node. Not sure how common this is. > The disadvantage of this solution is that it can happen to end in a > non-booting device for FPGA platforms using overlays to programm the > bit stream and forget to enable CONFIG_OF_OVERLAY_LIVE because the > kernel tries to access regions not existing. > > I've discussed this with Michael in private but we didn't came to a > conclusion. Therefore I'm asking here any input would be helpfull :) Regards, Rouven Czerwinski _______________________________________________ barebox mailing list barebox@lists.infradead.org http://lists.infradead.org/mailman/listinfo/barebox ^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: Barebox OF-Overlay Handling 2021-01-13 14:07 ` Rouven Czerwinski @ 2021-01-13 14:52 ` Michael Tretter 2021-01-15 13:47 ` Michael Tretter 0 siblings, 1 reply; 4+ messages in thread From: Michael Tretter @ 2021-01-13 14:52 UTC (permalink / raw) To: Rouven Czerwinski; +Cc: barebox, Marco Felsch On Wed, 13 Jan 2021 15:07:48 +0100, Rouven Czerwinski wrote: > On Wed, 2021-01-13 at 12:07 +0100, Marco Felsch wrote: > > Hi there, > > > > I have the following problem. My customer is using overlays for > > external devices like: display, camera, etc. The current overlay support > > is awesome and most of it works out of the box. There is only one > > nitpick: If Barebox isn't build with CONFIG_OF_OVERLAY_LIVE enabled many > > error's are printed during boot. Those error's are ignored but let the > > user assume that something went really bad: > > > > ERROR: of_resolver: __symbols__ missing from base devicetree > > ERROR: of_overlay: fragment 30164b88: phandle 0xffffffff not found > > ERROR: of_overlay: fragment 30164c84: phandle 0xffffffff not found > > ERROR: of_overlay: fragment 3012fb08: phandle 0xffffffff not found > > ERROR: of_overlay: fragment 3012fc34: phandle 0xffffffff not found > > ERROR: of_overlay: fragment 3012fd60: phandle 0xffffffff not found > > ERROR: of_overlay: fragment 3012fe8c: phandle 0xffffffff not found > > ERROR: of_overlay: fragment 3012ffb8: phandle 0xffffwfffffff not found > > ERROR: of_overlay: fragment 301300e4: phandle 0xffffffff not found > > ERROR: of_overlay: fragment 30130210: phandle 0xffffffff not found > > ERROR: of_overlay: fragment 3013033c: phandle 0xffffffff not found > > ERROR: of_resolver: __symbols__ missing from base devicetree > > ERROR: of_overlay: fragment 30130e94: phandle 0xffffffff not found > > ERROR: of_overlay: fragment 30130fc4: phandle 0xffffffff not found > > ERROR: of_resolver: __symbols__ missing from base devicetree > > ERROR: of_overlay: fragment 30131a14: phandle 0xffffffff not found > > ERROR: of_overlay: fragment 301342d4: phandle 0xffffffff not found > > > > The of_firmware_load_overlay() calls triggering those errors. > > The error's by itself are correct and I don't wanna change them but the > > context must be correct by context I mean: > > > > - barebox-dt on fpga-platform: An FPGA platform needs a barebox > > base devicetree with __symbols__ and those error are correct because > > the firmware manager needs to load the firmware. > > - barebox-dt on non fpga-platform: Those errors are not correct. > > We don't need __symbols__ for the barebox base devicetree. > > I was wondering why you were getting this error even on a platform > without FPGA, turns out of_firmware_load_overlay() is always called if > a devicetree overlay is passed via the DT. This in itself isn't a > problem, but IMO of_firmware_load_overlay() should check first whether > the overlay contains the right compatible ("fpga-region") and property > ("firmware-name") before doing of_resolve_phandles and > of_process_overlay. This way we can skip a lot of unnecessary overlay > handling if we don't end up loading a firmware. At the moment, the check and firmware load path use the same code path, because there is no difference except that firmware load requires a resolved overlay and the check does not. This is a viable solution and there is even a helper to iterate the fragments and call a check function for each fragment. However the helper calls find_target, which is responsible for most of the error messages, and therefore, does not completely resolve the issue. (Indeed, the check if the fragment has the "fpga-region" compatible is missing. That's a bug.) I would rather change the error logging to only log errors if actually something goes wrong. Because none of the aforementioned errors is actually fatal from a system perspective, but only from a function perspective. Furthermore, the messages are not helpful at all to actually find the problem in case of a unresolved overlay. > > > - kernel-dt on any platform: Those error's are correct if > > the overlays are using phandles which should be the case most the > > time. > > AFAICS this should also fix this case. > > > My proposed solution would be a stub like this: > > > > #ifdef CONFIG_OF_OVERLAY_LIVE > > int of_firmware_load_overlay(struct device_node *overlay, const char *path); > > #else > > static inline int of_firmware_load_overlay(struct device_node *overlay, const char *path) > > { > > return 0; > > } > > #endif /* CONFIG_OF_OVERLAY_LIVE */ Nack. of_firmware_load_overlay must fail if the overlay describes an fpga-region. Otherwise the device tree that is passed to the kernel might have an fpga-region with a firmware-name property and that per specification requires that the fpga is programmed. Michael > > While correct in case all firmware overlays use phandles, in theory > overlays could be purely path-based, with not dependency on the > __symbols__ node. Not sure how common this is. > > > The disadvantage of this solution is that it can happen to end in a > > non-booting device for FPGA platforms using overlays to programm the > > bit stream and forget to enable CONFIG_OF_OVERLAY_LIVE because the > > kernel tries to access regions not existing. > > > > I've discussed this with Michael in private but we didn't came to a > > conclusion. Therefore I'm asking here any input would be helpfull :) > > Regards, > Rouven Czerwinski > > _______________________________________________ barebox mailing list barebox@lists.infradead.org http://lists.infradead.org/mailman/listinfo/barebox ^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: Barebox OF-Overlay Handling 2021-01-13 14:52 ` Michael Tretter @ 2021-01-15 13:47 ` Michael Tretter 0 siblings, 0 replies; 4+ messages in thread From: Michael Tretter @ 2021-01-15 13:47 UTC (permalink / raw) To: Rouven Czerwinski; +Cc: barebox, Marco Felsch On Wed, 13 Jan 2021 15:52:23 +0100, Michael Tretter wrote: > On Wed, 13 Jan 2021 15:07:48 +0100, Rouven Czerwinski wrote: > > On Wed, 2021-01-13 at 12:07 +0100, Marco Felsch wrote: > > > Hi there, > > > > > > I have the following problem. My customer is using overlays for > > > external devices like: display, camera, etc. The current overlay support > > > is awesome and most of it works out of the box. There is only one > > > nitpick: If Barebox isn't build with CONFIG_OF_OVERLAY_LIVE enabled many > > > error's are printed during boot. Those error's are ignored but let the > > > user assume that something went really bad: > > > > > > ERROR: of_resolver: __symbols__ missing from base devicetree > > > ERROR: of_overlay: fragment 30164b88: phandle 0xffffffff not found > > > ERROR: of_overlay: fragment 30164c84: phandle 0xffffffff not found > > > ERROR: of_overlay: fragment 3012fb08: phandle 0xffffffff not found > > > ERROR: of_overlay: fragment 3012fc34: phandle 0xffffffff not found > > > ERROR: of_overlay: fragment 3012fd60: phandle 0xffffffff not found > > > ERROR: of_overlay: fragment 3012fe8c: phandle 0xffffffff not found > > > ERROR: of_overlay: fragment 3012ffb8: phandle 0xffffwfffffff not found > > > ERROR: of_overlay: fragment 301300e4: phandle 0xffffffff not found > > > ERROR: of_overlay: fragment 30130210: phandle 0xffffffff not found > > > ERROR: of_overlay: fragment 3013033c: phandle 0xffffffff not found > > > ERROR: of_resolver: __symbols__ missing from base devicetree > > > ERROR: of_overlay: fragment 30130e94: phandle 0xffffffff not found > > > ERROR: of_overlay: fragment 30130fc4: phandle 0xffffffff not found > > > ERROR: of_resolver: __symbols__ missing from base devicetree > > > ERROR: of_overlay: fragment 30131a14: phandle 0xffffffff not found > > > ERROR: of_overlay: fragment 301342d4: phandle 0xffffffff not found > > > > > > The of_firmware_load_overlay() calls triggering those errors. > > > The error's by itself are correct and I don't wanna change them but the > > > context must be correct by context I mean: > > > > > > - barebox-dt on fpga-platform: An FPGA platform needs a barebox > > > base devicetree with __symbols__ and those error are correct because > > > the firmware manager needs to load the firmware. > > > - barebox-dt on non fpga-platform: Those errors are not correct. > > > We don't need __symbols__ for the barebox base devicetree. > > > > I was wondering why you were getting this error even on a platform > > without FPGA, turns out of_firmware_load_overlay() is always called if > > a devicetree overlay is passed via the DT. This in itself isn't a > > problem, but IMO of_firmware_load_overlay() should check first whether > > the overlay contains the right compatible ("fpga-region") and property > > ("firmware-name") before doing of_resolve_phandles and > > of_process_overlay. This way we can skip a lot of unnecessary overlay > > handling if we don't end up loading a firmware. > > At the moment, the check and firmware load path use the same code path, > because there is no difference except that firmware load requires a resolved > overlay and the check does not. This is a viable solution and there is even a > helper to iterate the fragments and call a check function for each fragment. > However the helper calls find_target, which is responsible for most of the > error messages, and therefore, does not completely resolve the issue. > > (Indeed, the check if the fragment has the "fpga-region" compatible is > missing. That's a bug.) This is wrong. The overlay does not have the "fpga-region" compatible. Only the target node determines if an overlay targets an fpga-region or not. Michael > > I would rather change the error logging to only log errors if actually > something goes wrong. Because none of the aforementioned errors is actually > fatal from a system perspective, but only from a function perspective. > Furthermore, the messages are not helpful at all to actually find the problem > in case of a unresolved overlay. > > > > > > - kernel-dt on any platform: Those error's are correct if > > > the overlays are using phandles which should be the case most the > > > time. > > > > AFAICS this should also fix this case. > > > > > My proposed solution would be a stub like this: > > > > > > #ifdef CONFIG_OF_OVERLAY_LIVE > > > int of_firmware_load_overlay(struct device_node *overlay, const char *path); > > > #else > > > static inline int of_firmware_load_overlay(struct device_node *overlay, const char *path) > > > { > > > return 0; > > > } > > > #endif /* CONFIG_OF_OVERLAY_LIVE */ > > Nack. of_firmware_load_overlay must fail if the overlay describes an > fpga-region. Otherwise the device tree that is passed to the kernel might have > an fpga-region with a firmware-name property and that per specification > requires that the fpga is programmed. > > Michael > > > > > While correct in case all firmware overlays use phandles, in theory > > overlays could be purely path-based, with not dependency on the > > __symbols__ node. Not sure how common this is. > > > > > > The disadvantage of this solution is that it can happen to end in a > > > non-booting device for FPGA platforms using overlays to programm the > > > bit stream and forget to enable CONFIG_OF_OVERLAY_LIVE because the > > > kernel tries to access regions not existing. > > > > > > I've discussed this with Michael in private but we didn't came to a > > > conclusion. Therefore I'm asking here any input would be helpfull :) > > > > Regards, > > Rouven Czerwinski > > > > _______________________________________________ barebox mailing list barebox@lists.infradead.org http://lists.infradead.org/mailman/listinfo/barebox ^ permalink raw reply [flat|nested] 4+ messages in thread
end of thread, other threads:[~2021-01-15 13:47 UTC | newest] Thread overview: 4+ messages (download: mbox.gz / follow: Atom feed) -- links below jump to the message on this page -- 2021-01-13 11:07 Barebox OF-Overlay Handling Marco Felsch 2021-01-13 14:07 ` Rouven Czerwinski 2021-01-13 14:52 ` Michael Tretter 2021-01-15 13:47 ` Michael Tretter
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