Hi Andy and Adrian, Thanks for your clarifications On Mon, 5 Dec 2022 at 16:33, Adrian Hunter <adrian.hunter@xxxxxxxxx> wrote: > > On 5/12/22 16:17, Andy Shevchenko wrote: > > On Mon, Dec 5, 2022 at 4:14 PM Andy Shevchenko > > <andy.shevchenko@xxxxxxxxx> wrote: > >> > >> On Mon, Dec 5, 2022 at 3:41 PM Adrian Hunter <adrian.hunter@xxxxxxxxx> wrote: > >>> On 5/12/22 15:25, Andy Shevchenko wrote: > >>>> On Mon, Dec 5, 2022 at 1:20 PM Tomer Maimon <tmaimon77@xxxxxxxxx> wrote: > >>>>> On Mon, 5 Dec 2022 at 12:54, Andy Shevchenko <andy.shevchenko@xxxxxxxxx> wrote: > >>>>>> On Mon, Dec 5, 2022 at 10:54 AM Tomer Maimon <tmaimon77@xxxxxxxxx> wrote: > >> > >> ... > >> > >>>>>>> + pltfm_host->clk = devm_clk_get_optional(&pdev->dev, NULL); > >>>>>> > >>>>>> You can't mix devm with non-devm in this way. > >>>>> Can you explain what you mean You can't mix devm with non-devm in this > >>>>> way, where is the mix? > >>>>> In version 1 used devm_clk_get, is it problematic? > >>>> > >>>> devm_ is problematic in your case. > >>>> TL;DR: you need to use clk_get_optional() and clk_put(). > >>> > >>> devm_ calls exactly those, so what is the issue? > >> > >> The issue is the error path or removal stage where it may or may be > >> not problematic. To be on the safe side, the best approach is to make > >> sure that allocated resources are being deallocated in the reversed > >> order. That said, the > >> > >> 1. call non-devm_func() > >> 2. call devm_func() > >> > >> is wrong strictly speaking. > > > > To elaborate more, the > > > > 1. call all devm_func() > > 2. call only non-devm_func() > > > > is the correct order. > > 1. WRT pltfm_host->clk, that is what is happening > 2. WRT other resources that is simply not always possible because not every resource is wrapped by devm_ > e.g. mmc_alloc_host() / mmc_free_host() I little confused about what to decide, should I use only non-devm_func because mmc_alloc_host() / mmc_free_host() is not warrped with devm_? > > > > > Hence in this case the driver can be worked around easily (by > > shuffling the order in ->probe() to call devm_ first), but as I said > > looking into implementation of the _unregister() I'm pretty sure that > > clock management should be in sdhci-pltfm, rather than in all callers > > who won't need the full customization. > > > > Hope this helps to understand my point. > > > >>>> Your ->remove() callback doesn't free resources in the reversed order > >>>> which may or, by luck, may not be the case of all possible crashes, > >>>> UAFs, races, etc during removal stage. All the same for error path in > >>>> ->probe(). > >> > >> I also pointed out above what would be the outcome of neglecting this rule. > >> > >>>>>>> + if (IS_ERR(pltfm_host->clk)) > >>>>>>> + return PTR_ERR(pltfm_host->clk); > >>>>>>> + > >>>>>>> + ret = clk_prepare_enable(pltfm_host->clk); > >>>>>>> + if (ret) > >>>>>>> + return ret; > >>>>>>> + > >>>>>>> + caps = sdhci_readl(host, SDHCI_CAPABILITIES); > >>>>>>> + if (caps & SDHCI_CAN_DO_8BIT) > >>>>>>> + host->mmc->caps |= MMC_CAP_8_BIT_DATA; > >>>>>>> + > >>>>>>> + ret = mmc_of_parse(host->mmc); > >>>>>>> + if (ret) > >>>>>>> + goto err_sdhci_add; > >>>>>>> + > >>>>>>> + ret = sdhci_add_host(host); > >>>>>>> + if (ret) > >>>>>>> + goto err_sdhci_add; > >>>>>> > >>>>>> Why can't you use sdhci_pltfm_register()? > >>>>> two things are missing in sdhci_pltfm_register > >>>>> 1. clock. > >>>> > >>>> Taking into account the implementation of the corresponding > >>>> _unregister() I would add the clock handling to the _register() one. > >>>> Perhaps via a new member of the platform data that supplies the name > >>>> and index of the clock and hence all clk_get_optional() / clk_put will > >>>> be moved there. Do you mean to add it to sdhci_pltfm_register function? if yes I believe it will take some time to modify sdhci_pltfm_register I prefer not to use sdhci_pltfm_register. > >>>> > >>>>> 2. Adding SDHCI_CAN_DO_8BIT capability according the eMMC capabilities. > >>>> > >>>> All the same, why can't platform data be utilised for this? > >>>> > >>>>>>> + return 0; > >>>>>>> + > >>>>>>> +err_sdhci_add: > >>>>>>> + clk_disable_unprepare(pltfm_host->clk); > >>>>>>> + sdhci_pltfm_free(pdev); > >>>>>>> + return ret; > >>>>>>> +} > >> > >> > >> -- > >> With Best Regards, > >> Andy Shevchenko > > > > > > > Best regards, Tomer
