Overlay sugar syntax (was: Re: [PATCH v6 3/4] drm: rcar-du: Fix legacy DT to create LVDS encoder nodes)
Hi Frank,
On Fri, Feb 23, 2018 at 3:38 AM, Frank Rowand frowand.list@gmail.com wrote:
I was hoping to be able to convert the .dts files to use sugar syntax instead of hand coding the fragment nodes, but for this specific set of files I failed, since the labels that would have been required do not already exist in the base .dts files that that overlays would be applied against.
Indeed, hence the fixup overlays use "target-path".
BTW, is there any specific reason there is no sugar syntax support in dtc for absolute target paths? I guess to prevent adding stuff to a random existing node, and to encourage people to use a "connector" API defined in term of labels?
I'm also in the process of converting my collection of DT overlays to sugar syntax, and lack of support for "target-path" is the sole thing that holds me back from completing this. So for now I use a mix of sugar and traditional overlay syntax.
In particular, I need "target-path" for two things: 1. To refer to the root node, for adding devices that should live at (a board subnode of) the root node, like: - devices connected to GPIO controllers provided by other base or overlay devices (e.g. LEDs, displays, buttons, ...), - clock providers for other overlays devices (e.g. fixed-clock). 2. To refer to the aliases node, for adding mandatory serialX aliases.
The former is the real blocker for me.
The latter doesn't work with plain upstream (hacky patches available), so I'm working on getting rid of the serialX requirement in the serial driver.
Thanks!
Gr{oetje,eeting}s,
Geert
-- Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org
In personal conversations with technical people, I call myself a hacker. But when I'm talking to journalists I just say "programmer" or something like that. -- Linus Torvalds
On Fri, Feb 23, 2018 at 09:05:24AM +0100, Geert Uytterhoeven wrote:
Hi Frank,
On Fri, Feb 23, 2018 at 3:38 AM, Frank Rowand frowand.list@gmail.com wrote:
I was hoping to be able to convert the .dts files to use sugar syntax instead of hand coding the fragment nodes, but for this specific set of files I failed, since the labels that would have been required do not already exist in the base .dts files that that overlays would be applied against.
Indeed, hence the fixup overlays use "target-path".
BTW, is there any specific reason there is no sugar syntax support in dtc for absolute target paths? I guess to prevent adding stuff to a random existing node, and to encourage people to use a "connector" API defined in term of labels?
Only because it hasn't been implemented. Using &{/whatever} should IMO generate a target-path and the fact it doesn't is a bug.
I'm also in the process of converting my collection of DT overlays to sugar syntax, and lack of support for "target-path" is the sole thing that holds me back from completing this. So for now I use a mix of sugar and traditional overlay syntax.
In particular, I need "target-path" for two things:
- To refer to the root node, for adding devices that should live at (a board subnode of) the root node, like:
- devices connected to GPIO controllers provided by other base or overlay devices (e.g. LEDs, displays, buttons, ...),
- clock providers for other overlays devices (e.g. fixed-clock).
- To refer to the aliases node, for adding mandatory serialX aliases.
The former is the real blocker for me.
The latter doesn't work with plain upstream (hacky patches available), so I'm working on getting rid of the serialX requirement in the serial driver.
Below is draft patch adding target-path support. The pretty minimal test examples do include a case using &{/}
From 8f1b35f88395adea01ce1100c5faa27dacbc8410 Mon Sep 17 00:00:00 2001 From: David Gibson david@gibson.dropbear.id.au Date: Tue, 6 Mar 2018 13:27:53 +1100 Subject: [PATCH] Correct overlay syntactic sugar for generating target-path fragments
We've recently added "syntactic sugar" support to generate runtime dtb overlays using similar syntax to the compile time overlays we've had for a while. This worked with the &label { ... } syntax, adjusting an existing labelled node, but would fail with the &{/path} { ... } syntax attempting to adjust an existing node referenced by its path.
The previous code would always try to use the "target" property in the output overlay, which needs to be fixed up, and __fixups__ can only encode symbols, not paths, so the result could never work properly.
This adds support for the &{/path} syntax for overlays, translating it into the "target-path" encoding in the output. It also changes existing behaviour a little because we now unconditionally one fragment for each overlay section in the source. Previously we would only create a fragment if we couldn't locally resolve the node referenced. We need this for path references, because the path is supposed to be referencing something in the (not yet known) base tree, rather than the overlay tree we are working with now. In particular one useful case for path based overlays is using &{/} - but the constructed overlay tree will always have a root node, meaning that without the change that would attempt to resolve the fragment locally, which is not what we want.
Signed-off-by: David Gibson david@gibson.dropbear.id.au --- dtc-parser.y | 22 +++++++++--------- livetree.c | 12 +++++++--- tests/overlay_overlay_bypath.dts | 48 ++++++++++++++++++++++++++++++++++++++++ tests/run_tests.sh | 12 ++++++++++ 4 files changed, 80 insertions(+), 14 deletions(-) create mode 100644 tests/overlay_overlay_bypath.dts
diff --git a/dtc-parser.y b/dtc-parser.y index 44af170..25e92d6 100644 --- a/dtc-parser.y +++ b/dtc-parser.y @@ -190,18 +190,18 @@ devicetree: } | devicetree DT_REF nodedef { - struct node *target = get_node_by_ref($1, $2); - - if (target) { - merge_nodes(target, $3); + /* + * We rely on the rule being always: + * versioninfo plugindecl memreserves devicetree + * so $-1 is what we want (plugindecl) + */ + if ($<flags>-1 & DTSF_PLUGIN) { + add_orphan_node($1, $3, $2); } else { - /* - * We rely on the rule being always: - * versioninfo plugindecl memreserves devicetree - * so $-1 is what we want (plugindecl) - */ - if ($<flags>-1 & DTSF_PLUGIN) - add_orphan_node($1, $3, $2); + struct node *target = get_node_by_ref($1, $2); + + if (target) + merge_nodes(target, $3); else ERROR(&@2, "Label or path %s not found", $2); } diff --git a/livetree.c b/livetree.c index 57b7db2..f691c9b 100644 --- a/livetree.c +++ b/livetree.c @@ -224,10 +224,16 @@ struct node * add_orphan_node(struct node *dt, struct node *new_node, char *ref) struct data d = empty_data; char *name;
- d = data_add_marker(d, REF_PHANDLE, ref); - d = data_append_integer(d, 0xffffffff, 32); + if (ref[0] == '/') { + d = data_append_data(d, ref, strlen(ref) + 1);
- p = build_property("target", d); + p = build_property("target-path", d); + } else { + d = data_add_marker(d, REF_PHANDLE, ref); + d = data_append_integer(d, 0xffffffff, 32); + + p = build_property("target", d); + }
xasprintf(&name, "fragment@%u", next_orphan_fragment++); diff --git a/tests/overlay_overlay_bypath.dts b/tests/overlay_overlay_bypath.dts new file mode 100644 index 0000000..f23e7b6 --- /dev/null +++ b/tests/overlay_overlay_bypath.dts @@ -0,0 +1,48 @@ +/* + * Copyright (c) 2016 NextThing Co + * Copyright (c) 2016 Free Electrons + * Copyright (c) 2016 Konsulko Inc. + * + * SPDX-License-Identifier: GPL-2.0+ + */ + +/dts-v1/; +/plugin/; + +/* Test that we can change an int by another */ +&{/test-node} { + test-int-property = <43>; +}; + +/* Test that we can replace a string by a longer one */ +&{/test-node} { + test-str-property = "foobar"; +}; + +/* Test that we add a new property */ +&{/test-node} { + test-str-property-2 = "foobar2"; +}; + +/* Test that we add a new node (by phandle) */ +&{/test-node} { + new-node { + new-property; + }; +}; + +&{/} { + local: new-local-node { + new-property; + }; +}; + +&{/} { + test-several-phandle = <&local>, <&local>; +}; + +&{/test-node} { + sub-test-node { + new-sub-test-property; + }; +}; diff --git a/tests/run_tests.sh b/tests/run_tests.sh index 4d944fa..c2ce1e6 100755 --- a/tests/run_tests.sh +++ b/tests/run_tests.sh @@ -251,13 +251,25 @@ dtc_overlay_tests () { run_test check_path overlay_overlay_nosugar.test.dtb exists "/__fixups__" run_test check_path overlay_overlay_nosugar.test.dtb exists "/__local_fixups__"
+ # Using target-path + run_dtc_test -I dts -O dtb -o overlay_overlay_bypath.test.dtb overlay_overlay_bypath.dts + run_test check_path overlay_overlay_bypath.test.dtb not-exists "/__symbols__" + run_test check_path overlay_overlay_bypath.test.dtb not-exists "/__fixups__" + run_test check_path overlay_overlay_bypath.test.dtb exists "/__local_fixups__" + # Check building works the same as manual constructions run_test dtbs_equal_ordered overlay_overlay.test.dtb overlay_overlay_nosugar.test.dtb
run_dtc_test -I dts -O dtb -o overlay_overlay_manual_fixups.test.dtb overlay_overlay_manual_fixups.dts run_test dtbs_equal_ordered overlay_overlay.test.dtb overlay_overlay_manual_fixups.test.dtb
+ run_dtc_test -I dts -O dtb -o overlay_overlay_no_fixups.test.dtb overlay_overlay_no_fixups.dts + run_test dtbs_equal_ordered overlay_overlay_bypath.test.dtb overlay_overlay_no_fixups.test.dtb + + # Check we can actually apply the result + run_dtc_test -I dts -O dtb -o overlay_base_no_symbols.test.dtb overlay_base.dts run_test overlay overlay_base.test.dtb overlay_overlay.test.dtb + run_test overlay overlay_base_no_symbols.test.dtb overlay_overlay_bypath.test.dtb
# test plugin source to dtb and back run_dtc_test -I dtb -O dts -o overlay_overlay_decompile.test.dts overlay_overlay.test.dtb
Hi David,
On Tue, Mar 6, 2018 at 4:54 AM, David Gibson david@gibson.dropbear.id.au wrote:
On Fri, Feb 23, 2018 at 09:05:24AM +0100, Geert Uytterhoeven wrote:
On Fri, Feb 23, 2018 at 3:38 AM, Frank Rowand frowand.list@gmail.com wrote:
I was hoping to be able to convert the .dts files to use sugar syntax instead of hand coding the fragment nodes, but for this specific set of files I failed, since the labels that would have been required do not already exist in the base .dts files that that overlays would be applied against.
Indeed, hence the fixup overlays use "target-path".
BTW, is there any specific reason there is no sugar syntax support in dtc for absolute target paths? I guess to prevent adding stuff to a random existing node, and to encourage people to use a "connector" API defined in term of labels?
Only because it hasn't been implemented. Using &{/whatever} should IMO generate a target-path and the fact it doesn't is a bug.
I'm also in the process of converting my collection of DT overlays to sugar syntax, and lack of support for "target-path" is the sole thing that holds me back from completing this. So for now I use a mix of sugar and traditional overlay syntax.
In particular, I need "target-path" for two things:
- To refer to the root node, for adding devices that should live at (a board subnode of) the root node, like:
- devices connected to GPIO controllers provided by other base or overlay devices (e.g. LEDs, displays, buttons, ...),
- clock providers for other overlays devices (e.g. fixed-clock).
The former is the real blocker for me.
Below is draft patch adding target-path support. The pretty minimal test examples do include a case using &{/}
From 8f1b35f88395adea01ce1100c5faa27dacbc8410 Mon Sep 17 00:00:00 2001 From: David Gibson david@gibson.dropbear.id.au Date: Tue, 6 Mar 2018 13:27:53 +1100 Subject: [PATCH] Correct overlay syntactic sugar for generating target-path fragments
We've recently added "syntactic sugar" support to generate runtime dtb overlays using similar syntax to the compile time overlays we've had for a while. This worked with the &label { ... } syntax, adjusting an existing labelled node, but would fail with the &{/path} { ... } syntax attempting to adjust an existing node referenced by its path.
The previous code would always try to use the "target" property in the output overlay, which needs to be fixed up, and __fixups__ can only encode symbols, not paths, so the result could never work properly.
This adds support for the &{/path} syntax for overlays, translating it into the "target-path" encoding in the output. It also changes existing behaviour a little because we now unconditionally one fragment for each overlay section in the source. Previously we would only create a fragment if we couldn't locally resolve the node referenced. We need this for path references, because the path is supposed to be referencing something in the (not yet known) base tree, rather than the overlay tree we are working with now. In particular one useful case for path based overlays is using &{/} - but the constructed overlay tree will always have a root node, meaning that without the change that would attempt to resolve the fragment locally, which is not what we want.
Signed-off-by: David Gibson david@gibson.dropbear.id.au
Thank you, seems to work fine on dtc.git.
Note that while the dtc part applies on the in-kernel copy of dtc, it doesn't work there: "&{/}" behaves the same as "/" (i.e. no overlay fragment is generated), but "&{/foo}" does create the overlay fragment. Merging in Rob's for-next branch to upgrade Linux' copy of dtc fixes that.
Thanks a lot! Converting my remaining overlay fragments to sugar syntax...
Gr{oetje,eeting}s,
Geert
-- Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org
In personal conversations with technical people, I call myself a hacker. But when I'm talking to journalists I just say "programmer" or something like that. -- Linus Torvalds
On Tue, Mar 06, 2018 at 01:30:05PM +0100, Geert Uytterhoeven wrote:
Hi David,
On Tue, Mar 6, 2018 at 4:54 AM, David Gibson david@gibson.dropbear.id.au wrote:
On Fri, Feb 23, 2018 at 09:05:24AM +0100, Geert Uytterhoeven wrote:
On Fri, Feb 23, 2018 at 3:38 AM, Frank Rowand frowand.list@gmail.com wrote:
I was hoping to be able to convert the .dts files to use sugar syntax instead of hand coding the fragment nodes, but for this specific set of files I failed, since the labels that would have been required do not already exist in the base .dts files that that overlays would be applied against.
Indeed, hence the fixup overlays use "target-path".
BTW, is there any specific reason there is no sugar syntax support in dtc for absolute target paths? I guess to prevent adding stuff to a random existing node, and to encourage people to use a "connector" API defined in term of labels?
Only because it hasn't been implemented. Using &{/whatever} should IMO generate a target-path and the fact it doesn't is a bug.
I'm also in the process of converting my collection of DT overlays to sugar syntax, and lack of support for "target-path" is the sole thing that holds me back from completing this. So for now I use a mix of sugar and traditional overlay syntax.
In particular, I need "target-path" for two things:
- To refer to the root node, for adding devices that should live at (a board subnode of) the root node, like:
- devices connected to GPIO controllers provided by other base or overlay devices (e.g. LEDs, displays, buttons, ...),
- clock providers for other overlays devices (e.g. fixed-clock).
The former is the real blocker for me.
Below is draft patch adding target-path support. The pretty minimal test examples do include a case using &{/}
From 8f1b35f88395adea01ce1100c5faa27dacbc8410 Mon Sep 17 00:00:00 2001 From: David Gibson david@gibson.dropbear.id.au Date: Tue, 6 Mar 2018 13:27:53 +1100 Subject: [PATCH] Correct overlay syntactic sugar for generating target-path fragments
We've recently added "syntactic sugar" support to generate runtime dtb overlays using similar syntax to the compile time overlays we've had for a while. This worked with the &label { ... } syntax, adjusting an existing labelled node, but would fail with the &{/path} { ... } syntax attempting to adjust an existing node referenced by its path.
The previous code would always try to use the "target" property in the output overlay, which needs to be fixed up, and __fixups__ can only encode symbols, not paths, so the result could never work properly.
This adds support for the &{/path} syntax for overlays, translating it into the "target-path" encoding in the output. It also changes existing behaviour a little because we now unconditionally one fragment for each overlay section in the source. Previously we would only create a fragment if we couldn't locally resolve the node referenced. We need this for path references, because the path is supposed to be referencing something in the (not yet known) base tree, rather than the overlay tree we are working with now. In particular one useful case for path based overlays is using &{/} - but the constructed overlay tree will always have a root node, meaning that without the change that would attempt to resolve the fragment locally, which is not what we want.
Signed-off-by: David Gibson david@gibson.dropbear.id.au
Thank you, seems to work fine on dtc.git.
Note that while the dtc part applies on the in-kernel copy of dtc, it doesn't work there: "&{/}" behaves the same as "/" (i.e. no overlay fragment is generated), but "&{/foo}" does create the overlay fragment. Merging in Rob's for-next branch to upgrade Linux' copy of dtc fixes that.
I think that'll be because the kernel makefiles (at least by default) use a pre-generated version of the parser, rather than running bison. Since there were changes in the .y file, those will be missing which would cause the error you describe.
On Tue, Mar 6, 2018 at 8:07 AM, David Gibson david@gibson.dropbear.id.au wrote:
On Tue, Mar 06, 2018 at 01:30:05PM +0100, Geert Uytterhoeven wrote:
Hi David,
On Tue, Mar 6, 2018 at 4:54 AM, David Gibson david@gibson.dropbear.id.au wrote:
On Fri, Feb 23, 2018 at 09:05:24AM +0100, Geert Uytterhoeven wrote:
On Fri, Feb 23, 2018 at 3:38 AM, Frank Rowand frowand.list@gmail.com wrote:
I was hoping to be able to convert the .dts files to use sugar syntax instead of hand coding the fragment nodes, but for this specific set of files I failed, since the labels that would have been required do not already exist in the base .dts files that that overlays would be applied against.
Indeed, hence the fixup overlays use "target-path".
BTW, is there any specific reason there is no sugar syntax support in dtc for absolute target paths? I guess to prevent adding stuff to a random existing node, and to encourage people to use a "connector" API defined in term of labels?
Only because it hasn't been implemented. Using &{/whatever} should IMO generate a target-path and the fact it doesn't is a bug.
I'm also in the process of converting my collection of DT overlays to sugar syntax, and lack of support for "target-path" is the sole thing that holds me back from completing this. So for now I use a mix of sugar and traditional overlay syntax.
In particular, I need "target-path" for two things:
- To refer to the root node, for adding devices that should live at (a board subnode of) the root node, like:
- devices connected to GPIO controllers provided by other base or overlay devices (e.g. LEDs, displays, buttons, ...),
- clock providers for other overlays devices (e.g. fixed-clock).
The former is the real blocker for me.
Below is draft patch adding target-path support. The pretty minimal test examples do include a case using &{/}
From 8f1b35f88395adea01ce1100c5faa27dacbc8410 Mon Sep 17 00:00:00 2001 From: David Gibson david@gibson.dropbear.id.au Date: Tue, 6 Mar 2018 13:27:53 +1100 Subject: [PATCH] Correct overlay syntactic sugar for generating target-path fragments
We've recently added "syntactic sugar" support to generate runtime dtb overlays using similar syntax to the compile time overlays we've had for a while. This worked with the &label { ... } syntax, adjusting an existing labelled node, but would fail with the &{/path} { ... } syntax attempting to adjust an existing node referenced by its path.
The previous code would always try to use the "target" property in the output overlay, which needs to be fixed up, and __fixups__ can only encode symbols, not paths, so the result could never work properly.
This adds support for the &{/path} syntax for overlays, translating it into the "target-path" encoding in the output. It also changes existing behaviour a little because we now unconditionally one fragment for each overlay section in the source. Previously we would only create a fragment if we couldn't locally resolve the node referenced. We need this for path references, because the path is supposed to be referencing something in the (not yet known) base tree, rather than the overlay tree we are working with now. In particular one useful case for path based overlays is using &{/} - but the constructed overlay tree will always have a root node, meaning that without the change that would attempt to resolve the fragment locally, which is not what we want.
Signed-off-by: David Gibson david@gibson.dropbear.id.au
Thank you, seems to work fine on dtc.git.
Note that while the dtc part applies on the in-kernel copy of dtc, it doesn't work there: "&{/}" behaves the same as "/" (i.e. no overlay fragment is generated), but "&{/foo}" does create the overlay fragment. Merging in Rob's for-next branch to upgrade Linux' copy of dtc fixes that.
I think that'll be because the kernel makefiles (at least by default) use a pre-generated version of the parser, rather than running bison.
Just FYI, as of that branch, that is no longer true. We now run bison.
Since there were changes in the .y file, those will be missing which would cause the error you describe.
-- David Gibson | I'll have my music baroque, and my code david AT gibson.dropbear.id.au | minimalist, thank you. NOT _the_ _other_ | _way_ _around_! http://www.ozlabs.org/~dgibson
On 03/06/18 04:30, Geert Uytterhoeven wrote:
Hi David,
On Tue, Mar 6, 2018 at 4:54 AM, David Gibson david@gibson.dropbear.id.au wrote:
On Fri, Feb 23, 2018 at 09:05:24AM +0100, Geert Uytterhoeven wrote:
On Fri, Feb 23, 2018 at 3:38 AM, Frank Rowand frowand.list@gmail.com wrote:
I was hoping to be able to convert the .dts files to use sugar syntax instead of hand coding the fragment nodes, but for this specific set of files I failed, since the labels that would have been required do not already exist in the base .dts files that that overlays would be applied against.
Indeed, hence the fixup overlays use "target-path".
BTW, is there any specific reason there is no sugar syntax support in dtc for absolute target paths? I guess to prevent adding stuff to a random existing node, and to encourage people to use a "connector" API defined in term of labels?
Only because it hasn't been implemented. Using &{/whatever} should IMO generate a target-path and the fact it doesn't is a bug.
I'm also in the process of converting my collection of DT overlays to sugar syntax, and lack of support for "target-path" is the sole thing that holds me back from completing this. So for now I use a mix of sugar and traditional overlay syntax.
In particular, I need "target-path" for two things:
- To refer to the root node, for adding devices that should live at (a board subnode of) the root node, like:
- devices connected to GPIO controllers provided by other base or overlay devices (e.g. LEDs, displays, buttons, ...),
- clock providers for other overlays devices (e.g. fixed-clock).
The former is the real blocker for me.
Below is draft patch adding target-path support. The pretty minimal test examples do include a case using &{/}
From 8f1b35f88395adea01ce1100c5faa27dacbc8410 Mon Sep 17 00:00:00 2001 From: David Gibson david@gibson.dropbear.id.au Date: Tue, 6 Mar 2018 13:27:53 +1100 Subject: [PATCH] Correct overlay syntactic sugar for generating target-path fragments
We've recently added "syntactic sugar" support to generate runtime dtb overlays using similar syntax to the compile time overlays we've had for a while. This worked with the &label { ... } syntax, adjusting an existing labelled node, but would fail with the &{/path} { ... } syntax attempting to adjust an existing node referenced by its path.
The previous code would always try to use the "target" property in the output overlay, which needs to be fixed up, and __fixups__ can only encode symbols, not paths, so the result could never work properly.
This adds support for the &{/path} syntax for overlays, translating it into the "target-path" encoding in the output. It also changes existing behaviour a little because we now unconditionally one fragment for each overlay section in the source. Previously we would only create a fragment if we couldn't locally resolve the node referenced. We need this for path references, because the path is supposed to be referencing something in the (not yet known) base tree, rather than the overlay tree we are working with now. In particular one useful case for path based overlays is using &{/} - but the constructed overlay tree will always have a root node, meaning that without the change that would attempt to resolve the fragment locally, which is not what we want.
Signed-off-by: David Gibson david@gibson.dropbear.id.au
Thank you, seems to work fine on dtc.git.
And the patched dtc works for a dts file that I was trying to convert to sugar dts syntax in the thread that Geert was responding to when he created this thread.
(Laurent -- no need to worry about this for your current series. Converting your dts files will be an easy task to do in a future kernel version -- remind me if I forget to send a patch.)
-Frank
Note that while the dtc part applies on the in-kernel copy of dtc, it doesn't work there: "&{/}" behaves the same as "/" (i.e. no overlay fragment is generated), but "&{/foo}" does create the overlay fragment. Merging in Rob's for-next branch to upgrade Linux' copy of dtc fixes that.
Thanks a lot! Converting my remaining overlay fragments to sugar syntax...
Gr{oetje,eeting}s,
Geert-- Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org
In personal conversations with technical people, I call myself a hacker. But when I'm talking to journalists I just say "programmer" or something like that. -- Linus Torvalds .
On 03/06/18 11:51, Frank Rowand wrote:
On 03/06/18 04:30, Geert Uytterhoeven wrote:
Hi David,
On Tue, Mar 6, 2018 at 4:54 AM, David Gibson david@gibson.dropbear.id.au wrote:
On Fri, Feb 23, 2018 at 09:05:24AM +0100, Geert Uytterhoeven wrote:
On Fri, Feb 23, 2018 at 3:38 AM, Frank Rowand frowand.list@gmail.com wrote:
I was hoping to be able to convert the .dts files to use sugar syntax instead of hand coding the fragment nodes, but for this specific set of files I failed, since the labels that would have been required do not already exist in the base .dts files that that overlays would be applied against.
Indeed, hence the fixup overlays use "target-path".
BTW, is there any specific reason there is no sugar syntax support in dtc for absolute target paths? I guess to prevent adding stuff to a random existing node, and to encourage people to use a "connector" API defined in term of labels?
Only because it hasn't been implemented. Using &{/whatever} should IMO generate a target-path and the fact it doesn't is a bug.
I'm also in the process of converting my collection of DT overlays to sugar syntax, and lack of support for "target-path" is the sole thing that holds me back from completing this. So for now I use a mix of sugar and traditional overlay syntax.
In particular, I need "target-path" for two things:
- To refer to the root node, for adding devices that should live at (a board subnode of) the root node, like:
- devices connected to GPIO controllers provided by other base or overlay devices (e.g. LEDs, displays, buttons, ...),
- clock providers for other overlays devices (e.g. fixed-clock).
The former is the real blocker for me.
Below is draft patch adding target-path support. The pretty minimal test examples do include a case using &{/}
From 8f1b35f88395adea01ce1100c5faa27dacbc8410 Mon Sep 17 00:00:00 2001 From: David Gibson david@gibson.dropbear.id.au Date: Tue, 6 Mar 2018 13:27:53 +1100 Subject: [PATCH] Correct overlay syntactic sugar for generating target-path fragments
We've recently added "syntactic sugar" support to generate runtime dtb overlays using similar syntax to the compile time overlays we've had for a while. This worked with the &label { ... } syntax, adjusting an existing labelled node, but would fail with the &{/path} { ... } syntax attempting to adjust an existing node referenced by its path.
The previous code would always try to use the "target" property in the output overlay, which needs to be fixed up, and __fixups__ can only encode symbols, not paths, so the result could never work properly.
This adds support for the &{/path} syntax for overlays, translating it into the "target-path" encoding in the output. It also changes existing behaviour a little because we now unconditionally one fragment for each overlay section in the source. Previously we would only create a fragment if we couldn't locally resolve the node referenced. We need this for path references, because the path is supposed to be referencing something in the (not yet known) base tree, rather than the overlay tree we are working with now. In particular one useful case for path based overlays is using &{/} - but the constructed overlay tree will always have a root node, meaning that without the change that would attempt to resolve the fragment locally, which is not what we want.
Signed-off-by: David Gibson david@gibson.dropbear.id.au
Thank you, seems to work fine on dtc.git.
And the patched dtc works for a dts file that I was trying to convert to sugar dts syntax
< snip >
I noticed that a space in "&{/}" is an error. I wanted to check whether that was deliberate, or that the patch wasn't fully complete yet. cat path_sugar_v1.dts
$ nl -ba path_sugar_v1.dts 1 2 /dts-v1/; 3 /plugin/; 4 &{/} { 5 #address-cells = <2>; 6 #size-cells = <2>; 7 8 my_node@feb90000 { 9 compatible = "vendor,device"; 10 reg = <0 0xfeb90000 0 0x1c>; 11 12 }; 13 14 };
$ dtc -O dts path_sugar_v1.dts /dts-v1/;
/ {
fragment@0 { target-path = [2f 00];
__overlay__ { #address-cells = <0x2>; #size-cells = <0x2>;
my_node@feb90000 { compatible = "vendor,device"; reg = <0x0 0xfeb90000 0x0 0x1c>; }; }; }; };
$ nl -ba path_sugar_v2.dts 1 2 /dts-v1/; 3 /plugin/; 4 &{ / } { 5 #address-cells = <2>; 6 #size-cells = <2>; 7 8 my_node@feb90000 { 9 compatible = "vendor,device"; 10 reg = <0 0xfeb90000 0 0x1c>; 11 12 }; 13 14 };
$ dtc -O dts path_sugar_v2.dts Error: path_sugar_v2.dts:4.1-2 syntax error FATAL ERROR: Unable to parse input tree
On Tue, Mar 06, 2018 at 01:40:20PM -0800, Frank Rowand wrote:
On 03/06/18 11:51, Frank Rowand wrote:
On 03/06/18 04:30, Geert Uytterhoeven wrote:
Hi David,
On Tue, Mar 6, 2018 at 4:54 AM, David Gibson david@gibson.dropbear.id.au wrote:
On Fri, Feb 23, 2018 at 09:05:24AM +0100, Geert Uytterhoeven wrote:
On Fri, Feb 23, 2018 at 3:38 AM, Frank Rowand frowand.list@gmail.com wrote:
I was hoping to be able to convert the .dts files to use sugar syntax instead of hand coding the fragment nodes, but for this specific set of files I failed, since the labels that would have been required do not already exist in the base .dts files that that overlays would be applied against.
Indeed, hence the fixup overlays use "target-path".
BTW, is there any specific reason there is no sugar syntax support in dtc for absolute target paths? I guess to prevent adding stuff to a random existing node, and to encourage people to use a "connector" API defined in term of labels?
Only because it hasn't been implemented. Using &{/whatever} should IMO generate a target-path and the fact it doesn't is a bug.
I'm also in the process of converting my collection of DT overlays to sugar syntax, and lack of support for "target-path" is the sole thing that holds me back from completing this. So for now I use a mix of sugar and traditional overlay syntax.
In particular, I need "target-path" for two things:
- To refer to the root node, for adding devices that should live at (a board subnode of) the root node, like:
- devices connected to GPIO controllers provided by other base or overlay devices (e.g. LEDs, displays, buttons, ...),
- clock providers for other overlays devices (e.g. fixed-clock).
The former is the real blocker for me.
Below is draft patch adding target-path support. The pretty minimal test examples do include a case using &{/}
From 8f1b35f88395adea01ce1100c5faa27dacbc8410 Mon Sep 17 00:00:00 2001 From: David Gibson david@gibson.dropbear.id.au Date: Tue, 6 Mar 2018 13:27:53 +1100 Subject: [PATCH] Correct overlay syntactic sugar for generating target-path fragments
We've recently added "syntactic sugar" support to generate runtime dtb overlays using similar syntax to the compile time overlays we've had for a while. This worked with the &label { ... } syntax, adjusting an existing labelled node, but would fail with the &{/path} { ... } syntax attempting to adjust an existing node referenced by its path.
The previous code would always try to use the "target" property in the output overlay, which needs to be fixed up, and __fixups__ can only encode symbols, not paths, so the result could never work properly.
This adds support for the &{/path} syntax for overlays, translating it into the "target-path" encoding in the output. It also changes existing behaviour a little because we now unconditionally one fragment for each overlay section in the source. Previously we would only create a fragment if we couldn't locally resolve the node referenced. We need this for path references, because the path is supposed to be referencing something in the (not yet known) base tree, rather than the overlay tree we are working with now. In particular one useful case for path based overlays is using &{/} - but the constructed overlay tree will always have a root node, meaning that without the change that would attempt to resolve the fragment locally, which is not what we want.
Signed-off-by: David Gibson david@gibson.dropbear.id.au
Thank you, seems to work fine on dtc.git.
And the patched dtc works for a dts file that I was trying to convert to sugar dts syntax
< snip >
I noticed that a space in "&{/}" is an error. I wanted to check whether that was deliberate, or that the patch wasn't fully complete yet.
That's essentially deliberate - it's not really related to this patch at all. The patch just re-uses the existing syntax for a "path reference". The whole thing is treated as a single token, hence, no spaces.
It might be possible to change that, but it could introduce some complications when the path reference syntax is used in other places. So I'm disinclined to change it, unless there's a very strong reason to.
cat path_sugar_v1.dts
$ nl -ba path_sugar_v1.dts 1 2 /dts-v1/; 3 /plugin/; 4 &{/} { 5 #address-cells = <2>; 6 #size-cells = <2>; 7 8 my_node@feb90000 { 9 compatible = "vendor,device"; 10 reg = <0 0xfeb90000 0 0x1c>; 11 12 }; 13 14 };
$ dtc -O dts path_sugar_v1.dts /dts-v1/;
/ {
fragment@0 { target-path = [2f 00];
__overlay__ { #address-cells = <0x2>; #size-cells = <0x2>; my_node@feb90000 { compatible = "vendor,device"; reg = <0x0 0xfeb90000 0x0 0x1c>; }; };}; };
$ nl -ba path_sugar_v2.dts 1 2 /dts-v1/; 3 /plugin/; 4 &{ / } { 5 #address-cells = <2>; 6 #size-cells = <2>; 7 8 my_node@feb90000 { 9 compatible = "vendor,device"; 10 reg = <0 0xfeb90000 0 0x1c>; 11 12 }; 13 14 };
$ dtc -O dts path_sugar_v2.dts Error: path_sugar_v2.dts:4.1-2 syntax error FATAL ERROR: Unable to parse input tree
On 03/06/18 18:30, David Gibson wrote:
On Tue, Mar 06, 2018 at 01:40:20PM -0800, Frank Rowand wrote:
On 03/06/18 11:51, Frank Rowand wrote:
On 03/06/18 04:30, Geert Uytterhoeven wrote:
< snip >
And the patched dtc works for a dts file that I was trying to convert to sugar dts syntax
< snip >
I noticed that a space in "&{/}" is an error. I wanted to check whether that was deliberate, or that the patch wasn't fully complete yet.
That's essentially deliberate - it's not really related to this patch at all. The patch just re-uses the existing syntax for a "path reference". The whole thing is treated as a single token, hence, no spaces.
It might be possible to change that, but it could introduce some complications when the path reference syntax is used in other places. So I'm disinclined to change it, unless there's a very strong reason to.
< snip >
No, please do not change. I just wanted to make sure I understood the intended syntax.
BTW, thanks for all the time you've been putting into this recent stuff.
dri-devel@lists.freedesktop.org
-
David Gibson -
Frank Rowand -
Geert Uytterhoeven -
Rob Herring