From mboxrd@z Thu Jan 1 00:00:00 1970 From: Heiner Kallweit Subject: Re: [PATCH v2 6/9] mmc: meson-gx: remove unneeded meson_mmc_clk_set in meson_mmc_clk_init Date: Sat, 18 Feb 2017 11:49:22 +0100 Message-ID: References: <7d5263e2-9325-dedb-a5f6-954c4a09e977@gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8bit Return-path: Received: from mail-wr0-f195.google.com ([209.85.128.195]:33417 "EHLO mail-wr0-f195.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752158AbdBRKtz (ORCPT ); Sat, 18 Feb 2017 05:49:55 -0500 Received: by mail-wr0-f195.google.com with SMTP id g51so368740wrg.0 for ; Sat, 18 Feb 2017 02:49:38 -0800 (PST) In-Reply-To: Sender: linux-mmc-owner@vger.kernel.org List-Id: linux-mmc@vger.kernel.org To: =?UTF-8?Q?Micha=c5=82_Zegan?= , Ulf Hansson , Kevin Hilman Cc: linux-amlogic@lists.infradead.org, "linux-mmc@vger.kernel.org" Am 18.02.2017 um 11:37 schrieb Heiner Kallweit: > Am 18.02.2017 um 04:44 schrieb Michał Zegan: >> Hello Heiner, >> >> W dniu 16.02.2017 o 20:42, Heiner Kallweit pisze: >>> This clk_disable_unprepare isn't right here. At first the condition >>> should be "if (ret)" as the disable/unprepare is supposed to be >>> executed if the previous command fails. >>> And if the previous command fails and meson_mmc_clk_init returns >>> an error, then probe jumps to label free_host where we have this >>> disable/unprepare already. >>> >>> Signed-off-by: Heiner Kallweit >>> --- >>> v2: >>> - extended commit message >>> --- >>> drivers/mmc/host/meson-gx-mmc.c | 6 +----- >>> 1 file changed, 1 insertion(+), 5 deletions(-) >>> >>> diff --git a/drivers/mmc/host/meson-gx-mmc.c b/drivers/mmc/host/meson-gx-mmc.c >>> index 68e76fa8..850b0152 100644 >>> --- a/drivers/mmc/host/meson-gx-mmc.c >>> +++ b/drivers/mmc/host/meson-gx-mmc.c >>> @@ -320,11 +320,7 @@ static int meson_mmc_clk_init(struct meson_host *host) >>> /* Get the nearest minimum clock to 400KHz */ >>> host->mmc->f_min = clk_round_rate(host->cfg_div_clk, 400000); >>> >>> - ret = meson_mmc_clk_set(host, host->mmc->f_min); >>> - if (!ret) >>> - clk_disable_unprepare(host->cfg_div_clk); >>> - >>> - return ret; >>> + return meson_mmc_clk_set(host, host->mmc->f_min); >>> } >>> >>> static void meson_mmc_set_ios(struct mmc_host *mmc, struct mmc_ios *ios) >>> >> >> I see one problem here. >> As you said, if the previous command (that is the meson_mmc_clk_set >> function call) fails, then the whole meson_mmc_clk_init returns an error >> value, and meson_mmc_probe jumps to free_host and disables the clock there. >> But what happens if the clk_prepare_enable is the line that fails? in >> this case, the function returns an error value too, and in the free_host >> meson_mmc_probe tries to disable the clock that is not enabled, and that >> probably results in a kernel warning because you tried to disable a >> disabled clock. >> I was preparing a patch to disable clocks in the probe function only if >> they were enabled before, but then the meson_mmc_clk_init function >> remains a problem, because we don't know if the clock was enabled >> successfully or not when it returns an error. >> > Thanks for pointing out, you're right. The solution however should be > quite easy. I meson_mmc_clk_init we just change the condition of > the disable/unprepare to "if (ret)" and in probe we remove this > disable/unprepare from the error path. > This was a little too fast, it's not that easy. But I'll come up with a changed version.