| Message ID | 20220726062057.320342-1-wenst@chromium.org |
|---|---|
| State | New |
| Headers | show |
| Series | watchdog: mtk_wdt: Move mt6589-wdt fallback compatible to end of list | expand |
On 7/26/22 01:37, AngeloGioacchino Del Regno wrote: > Il 26/07/22 08:20, Chen-Yu Tsai ha scritto: >> The watchdog facility in the MediaTek SoCs are all the same, but the >> hardware block also contains a reset controller, which differs in the >> number of resets used between different SoCs. This difference is >> supported with of_device_get_match_data() supplying the number of reset >> lines for the newer compatible strings. The original mt6589-wdt only >> covers the watchdog facility. >> >> of_device_is_compatible(), and by extension of_device_get_match_data(), >> works by going through the given list of compatible strings sequentially, >> and checks if any of the device node's compatible strings match. >> >> To avoid early matching on the "mediatek,mt6589-wdt" fallback compatible, >> which only provides watchdog functionality and no reset controller, move >> the fallback entry to the end of the list, so that other, more specific >> compatible strings have a chance at getting matched. >> >> Fixes: c254e103082b ("watchdog: mtk_wdt: mt8183: Add reset controller") >> Fixes: adc318a34066 ("watchdog: mt8192: add wdt support") >> Fixes: 8c6b5ea6ac68 ("watchdog: mediatek: mt8195: add wdt support") >> Fixes: 4dbabc4d9e8c ("watchdog: mediatek: mt8186: add wdt support") >> Fixes: 711a5b25bac9 ("watchdog: mtk_wdt: mt7986: Add toprgu reset controller support") >> Signed-off-by: Chen-Yu Tsai <wenst@chromium.org> > > Uhm, I don't think that this is an issue? > > Ordering precedence is given to the list that you specify in devicetree, that's why > "the second one" is a fallback, meaning: ("impossible" example below) > > compatible = "mediatek,mt8195-wdt", "mediatek,mt8183-wdt", "mediatek,mt6589-wdt"; > > This gets walked as per the order in which you wrote the compatibles, so: > * Check match for mt8195-wdt, does not exist? > * Check match for mt8183-wdt, exists! > * Put everything into dev->of_node (having mediatek,mt8183-wdt only!) > > __of_device_is_compatible() gets dev->of_node and compares that to all of the > possible matches. > > struct device_node for this device hence does *not* contain any of the other > compatibles that we specified in devicetree, so it does *not* contain any of > "mediatek,mt8195-wdt", or "mediatek,mt6589-wdt", because we have previously > successfully matches 8183. > > I don't think that I've misinterpreted this flow, but if I have, let's pull > in devicetree people and check with them? > I don't see the problem either. The fallback needs to be listed last in the compatible property. If it isn't, having it last in struct of_device_id won't help either. > Cheers, > Angelo > >> --- >> >> This change complements the removal of the fallback compatible from the >> bindings and DTSI files [1]. >> If the fallback isn't listed in the dtsi files, it won't match at all, no matter where it is located in struct of_device_id. Guenter >> [1] https://lore.kernel.org/linux-mediatek/20220721014845.19044-1-allen-kh.cheng@mediatek.com/ >> >> drivers/watchdog/mtk_wdt.c | 3 ++- >> 1 file changed, 2 insertions(+), 1 deletion(-) >> >> diff --git a/drivers/watchdog/mtk_wdt.c b/drivers/watchdog/mtk_wdt.c >> index e97787536792..3d5a239b93ba 100644 >> --- a/drivers/watchdog/mtk_wdt.c >> +++ b/drivers/watchdog/mtk_wdt.c >> @@ -425,12 +425,13 @@ static int mtk_wdt_resume(struct device *dev) >> static const struct of_device_id mtk_wdt_dt_ids[] = { >> { .compatible = "mediatek,mt2712-wdt", .data = &mt2712_data }, >> - { .compatible = "mediatek,mt6589-wdt" }, >> { .compatible = "mediatek,mt7986-wdt", .data = &mt7986_data }, >> { .compatible = "mediatek,mt8183-wdt", .data = &mt8183_data }, >> { .compatible = "mediatek,mt8186-wdt", .data = &mt8186_data }, >> { .compatible = "mediatek,mt8192-wdt", .data = &mt8192_data }, >> { .compatible = "mediatek,mt8195-wdt", .data = &mt8195_data }, >> + /* Fallback compatible string must be last entry */ >> + { .compatible = "mediatek,mt6589-wdt" }, >> { /* sentinel */ } >> }; >> MODULE_DEVICE_TABLE(of, mtk_wdt_dt_ids); > >
On Tue, Jul 26, 2022 at 9:25 PM Guenter Roeck <linux@roeck-us.net> wrote: > > On 7/26/22 01:37, AngeloGioacchino Del Regno wrote: > > Il 26/07/22 08:20, Chen-Yu Tsai ha scritto: > >> The watchdog facility in the MediaTek SoCs are all the same, but the > >> hardware block also contains a reset controller, which differs in the > >> number of resets used between different SoCs. This difference is > >> supported with of_device_get_match_data() supplying the number of reset > >> lines for the newer compatible strings. The original mt6589-wdt only > >> covers the watchdog facility. > >> > >> of_device_is_compatible(), and by extension of_device_get_match_data(), > >> works by going through the given list of compatible strings sequentially, > >> and checks if any of the device node's compatible strings match. > >> > >> To avoid early matching on the "mediatek,mt6589-wdt" fallback compatible, > >> which only provides watchdog functionality and no reset controller, move > >> the fallback entry to the end of the list, so that other, more specific > >> compatible strings have a chance at getting matched. > >> > >> Fixes: c254e103082b ("watchdog: mtk_wdt: mt8183: Add reset controller") > >> Fixes: adc318a34066 ("watchdog: mt8192: add wdt support") > >> Fixes: 8c6b5ea6ac68 ("watchdog: mediatek: mt8195: add wdt support") > >> Fixes: 4dbabc4d9e8c ("watchdog: mediatek: mt8186: add wdt support") > >> Fixes: 711a5b25bac9 ("watchdog: mtk_wdt: mt7986: Add toprgu reset controller support") > >> Signed-off-by: Chen-Yu Tsai <wenst@chromium.org> > > > > Uhm, I don't think that this is an issue? > > > > Ordering precedence is given to the list that you specify in devicetree, that's why > > "the second one" is a fallback, meaning: ("impossible" example below) > > > > compatible = "mediatek,mt8195-wdt", "mediatek,mt8183-wdt", "mediatek,mt6589-wdt"; > > > > This gets walked as per the order in which you wrote the compatibles, so: > > * Check match for mt8195-wdt, does not exist? > > * Check match for mt8183-wdt, exists! > > * Put everything into dev->of_node (having mediatek,mt8183-wdt only!) > > > > __of_device_is_compatible() gets dev->of_node and compares that to all of the > > possible matches. > > > > struct device_node for this device hence does *not* contain any of the other > > compatibles that we specified in devicetree, so it does *not* contain any of > > "mediatek,mt8195-wdt", or "mediatek,mt6589-wdt", because we have previously > > successfully matches 8183. > > > > I don't think that I've misinterpreted this flow, but if I have, let's pull > > in devicetree people and check with them? > > > > I don't see the problem either. The fallback needs to be listed last in the > compatible property. If it isn't, having it last in struct of_device_id > won't help either. I was probably reading something that wasn't there in the watchdog patch series I mentioned. I've replied over there. Please ignore this one for now. ChenYu > > Cheers, > > Angelo > > > >> --- > >> > >> This change complements the removal of the fallback compatible from the > >> bindings and DTSI files [1]. > >> > > If the fallback isn't listed in the dtsi files, it won't match at all, > no matter where it is located in struct of_device_id. > > Guenter > > >> [1] https://lore.kernel.org/linux-mediatek/20220721014845.19044-1-allen-kh.cheng@mediatek.com/ > >> > >> drivers/watchdog/mtk_wdt.c | 3 ++- > >> 1 file changed, 2 insertions(+), 1 deletion(-) > >> > >> diff --git a/drivers/watchdog/mtk_wdt.c b/drivers/watchdog/mtk_wdt.c > >> index e97787536792..3d5a239b93ba 100644 > >> --- a/drivers/watchdog/mtk_wdt.c > >> +++ b/drivers/watchdog/mtk_wdt.c > >> @@ -425,12 +425,13 @@ static int mtk_wdt_resume(struct device *dev) > >> static const struct of_device_id mtk_wdt_dt_ids[] = { > >> { .compatible = "mediatek,mt2712-wdt", .data = &mt2712_data }, > >> - { .compatible = "mediatek,mt6589-wdt" }, > >> { .compatible = "mediatek,mt7986-wdt", .data = &mt7986_data }, > >> { .compatible = "mediatek,mt8183-wdt", .data = &mt8183_data }, > >> { .compatible = "mediatek,mt8186-wdt", .data = &mt8186_data }, > >> { .compatible = "mediatek,mt8192-wdt", .data = &mt8192_data }, > >> { .compatible = "mediatek,mt8195-wdt", .data = &mt8195_data }, > >> + /* Fallback compatible string must be last entry */ > >> + { .compatible = "mediatek,mt6589-wdt" }, > >> { /* sentinel */ } > >> }; > >> MODULE_DEVICE_TABLE(of, mtk_wdt_dt_ids); > > > > >
diff --git a/drivers/watchdog/mtk_wdt.c b/drivers/watchdog/mtk_wdt.c index e97787536792..3d5a239b93ba 100644 --- a/drivers/watchdog/mtk_wdt.c +++ b/drivers/watchdog/mtk_wdt.c @@ -425,12 +425,13 @@ static int mtk_wdt_resume(struct device *dev) static const struct of_device_id mtk_wdt_dt_ids[] = { { .compatible = "mediatek,mt2712-wdt", .data = &mt2712_data }, - { .compatible = "mediatek,mt6589-wdt" }, { .compatible = "mediatek,mt7986-wdt", .data = &mt7986_data }, { .compatible = "mediatek,mt8183-wdt", .data = &mt8183_data }, { .compatible = "mediatek,mt8186-wdt", .data = &mt8186_data }, { .compatible = "mediatek,mt8192-wdt", .data = &mt8192_data }, { .compatible = "mediatek,mt8195-wdt", .data = &mt8195_data }, + /* Fallback compatible string must be last entry */ + { .compatible = "mediatek,mt6589-wdt" }, { /* sentinel */ } }; MODULE_DEVICE_TABLE(of, mtk_wdt_dt_ids);
The watchdog facility in the MediaTek SoCs are all the same, but the hardware block also contains a reset controller, which differs in the number of resets used between different SoCs. This difference is supported with of_device_get_match_data() supplying the number of reset lines for the newer compatible strings. The original mt6589-wdt only covers the watchdog facility. of_device_is_compatible(), and by extension of_device_get_match_data(), works by going through the given list of compatible strings sequentially, and checks if any of the device node's compatible strings match. To avoid early matching on the "mediatek,mt6589-wdt" fallback compatible, which only provides watchdog functionality and no reset controller, move the fallback entry to the end of the list, so that other, more specific compatible strings have a chance at getting matched. Fixes: c254e103082b ("watchdog: mtk_wdt: mt8183: Add reset controller") Fixes: adc318a34066 ("watchdog: mt8192: add wdt support") Fixes: 8c6b5ea6ac68 ("watchdog: mediatek: mt8195: add wdt support") Fixes: 4dbabc4d9e8c ("watchdog: mediatek: mt8186: add wdt support") Fixes: 711a5b25bac9 ("watchdog: mtk_wdt: mt7986: Add toprgu reset controller support") Signed-off-by: Chen-Yu Tsai <wenst@chromium.org> --- This change complements the removal of the fallback compatible from the bindings and DTSI files [1]. [1] https://lore.kernel.org/linux-mediatek/20220721014845.19044-1-allen-kh.cheng@mediatek.com/ drivers/watchdog/mtk_wdt.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)