| Message ID | 20240827074857.2671808-1-xirui.zhang@vivo.com (mailing list archive) |
|---|---|
| Headers | show |
| Series | mmc: convert to devm_clk_get_enabled() API | expand |
On Tue, 27 Aug 2024 at 09:34, zhangxirui <xirui.zhang@vivo.com> wrote: > > This series use devm_clk_get_enabled() to simplify code > and avoids the calls to clk_disable_unprepare() I agree that it simplifies code - but it also changes the behaviour, in which order clocks are getting unprepared/disabled during the ->remove() phase. In other words, this needs to be thoroughly tested and not just considered as a trivial cleanup series. For example, if there is a PM domain attached to the mmc host device, is it really okay to allow powering-off the PM domain before the clocks are being gated? This could potentially happen if we apply the $subject series. Kind regards Uffe > > zhangxirui (9): > mmc: cavium-thunderx: Use devm_clk_get_enabled() helpers > mmc: davinci_mmc: Use devm_clk_get_enabled() helpers > mmc: dw_mmc-hi3798cv200: Use devm_clk_get_enabled() helpers > mmc: mvsdio: Use devm_clk_get_enabled() helpers > mmc: mxcmmc: Use devm_clk_get_enabled() helpers > mmc: mxs-mmc: Use devm_clk_get_enabled() helpers > mmc: sdhci: milbeaut: Use devm_clk_get_enabled() helpers > mmc: sdhci-of-arasan: Use devm_clk_get_enabled() helpers > mmc: sdhci_f_sdh30: Use devm_clk_get_enabled() helpers > > drivers/mmc/host/cavium-thunderx.c | 7 +----- > drivers/mmc/host/davinci_mmc.c | 8 +----- > drivers/mmc/host/dw_mmc-hi3798cv200.c | 28 +++------------------ > drivers/mmc/host/mvsdio.c | 13 +++------- > drivers/mmc/host/mxcmmc.c | 25 +++---------------- > drivers/mmc/host/mxs-mmc.c | 13 +++------- > drivers/mmc/host/sdhci-milbeaut.c | 25 +++---------------- > drivers/mmc/host/sdhci-of-arasan.c | 31 ++++------------------- > drivers/mmc/host/sdhci_f_sdh30.c | 36 ++++++++------------------- > 9 files changed, 35 insertions(+), 151 deletions(-) > > -- > 2.25.1 >
On Wed, 28 Aug 2024 at 17:11, Ulf Hansson <ulf.hansson@linaro.org> wrote: > On Tue, 27 Aug 2024 at 09:34, zhangxirui <xirui.zhang@vivo.com> wrote: > > > > This series use devm_clk_get_enabled() to simplify code > > and avoids the calls to clk_disable_unprepare() > > I agree that it simplifies code - but it also changes the behaviour, > in which order clocks are getting unprepared/disabled during the > ->remove() phase. In other words, this needs to be thoroughly tested > and not just considered as a trivial cleanup series. > > For example, if there is a PM domain attached to the mmc host device, > is it really okay to allow powering-off the PM domain before the > clocks are being gated? This could potentially happen if we apply the > $subject series. Thanks for the reply, are you saying that merging the above patch will lead to the following issue? before： bus_remove -> driver_remove -> clk unprepare -> dev_pm_domain_detach -> device_unbind_cleanup after： bus_remove -> driver_remove (delete clk unprepare) -> dev_pm_domain_detach -> device_unbind_cleanup (devm_clk_get_enbaled ->relase(clk unprepare)) But I think this issue is not only specific to the MMC host, it will also occur with other devices, if there is a PM domain attachded an use devm_clk_get_enbaled API. So, can we solve this problem by swap device_ubind_cleanup and dev_pm_domain_detach ? clk unprepare -> power off not power off -> clk unprepare bus_remove -> driver_remove -> device_unbind_cleanup -> dev_pm_domain_detach Thanks. > > > > zhangxirui (9): > > mmc: cavium-thunderx: Use devm_clk_get_enabled() helpers > > mmc: davinci_mmc: Use devm_clk_get_enabled() helpers > > mmc: dw_mmc-hi3798cv200: Use devm_clk_get_enabled() helpers > > mmc: mvsdio: Use devm_clk_get_enabled() helpers > > mmc: mxcmmc: Use devm_clk_get_enabled() helpers > > mmc: mxs-mmc: Use devm_clk_get_enabled() helpers > > mmc: sdhci: milbeaut: Use devm_clk_get_enabled() helpers > > mmc: sdhci-of-arasan: Use devm_clk_get_enabled() helpers > > mmc: sdhci_f_sdh30: Use devm_clk_get_enabled() helpers
+ Stephen On Fri, 30 Aug 2024 at 04:32, zhangxirui <xirui.zhang@vivo.com> wrote: > > On Wed, 28 Aug 2024 at 17:11, Ulf Hansson <ulf.hansson@linaro.org> wrote: > > > On Tue, 27 Aug 2024 at 09:34, zhangxirui <xirui.zhang@vivo.com> wrote: > > > > > > This series use devm_clk_get_enabled() to simplify code > > > and avoids the calls to clk_disable_unprepare() > > > > I agree that it simplifies code - but it also changes the behaviour, > > in which order clocks are getting unprepared/disabled during the > > ->remove() phase. In other words, this needs to be thoroughly tested > > and not just considered as a trivial cleanup series. > > > > For example, if there is a PM domain attached to the mmc host device, > > is it really okay to allow powering-off the PM domain before the > > clocks are being gated? This could potentially happen if we apply the > > $subject series. > > Thanks for the reply, are you saying that merging the above patch will > lead to the following issue? > > before： > bus_remove -> driver_remove -> clk unprepare > -> dev_pm_domain_detach > -> device_unbind_cleanup > after： > bus_remove -> driver_remove (delete clk unprepare) > -> dev_pm_domain_detach > -> device_unbind_cleanup (devm_clk_get_enbaled ->relase(clk unprepare)) Correct! > > But I think this issue is not only specific to the MMC host, it will also > occur with other devices, if there is a PM domain attachded an use devm_clk_get_enbaled API. Right. Which kind of questions whether the API is really that useful, from a cleanup point of view. > > So, can we solve this problem by swap device_ubind_cleanup and dev_pm_domain_detach ? > clk unprepare -> power off not power off -> clk unprepare That may work, I don't know. Another option is simply to avoid using devm_clk_get_enabled(), unless you know that the HW can cope with the potentially changed behaviour. I have looped in Stephen to allow him to provide us his thoughts around this too. > > bus_remove -> driver_remove > -> device_unbind_cleanup > -> dev_pm_domain_detach > > Thanks. > > > > > > > zhangxirui (9): > > > mmc: cavium-thunderx: Use devm_clk_get_enabled() helpers > > > mmc: davinci_mmc: Use devm_clk_get_enabled() helpers > > > mmc: dw_mmc-hi3798cv200: Use devm_clk_get_enabled() helpers > > > mmc: mvsdio: Use devm_clk_get_enabled() helpers > > > mmc: mxcmmc: Use devm_clk_get_enabled() helpers > > > mmc: mxs-mmc: Use devm_clk_get_enabled() helpers > > > mmc: sdhci: milbeaut: Use devm_clk_get_enabled() helpers > > > mmc: sdhci-of-arasan: Use devm_clk_get_enabled() helpers > > > mmc: sdhci_f_sdh30: Use devm_clk_get_enabled() helpers Kind regards Uffe