From mboxrd@z Thu Jan 1 00:00:00 1970 From: Adrian Hunter Subject: Re: [PATCH v3 1/2] mmc: sdhci: continue normal tuning if unsupported by platform tuning Date: Fri, 2 Dec 2016 16:18:55 +0200 Message-ID: <0edcfd1d-e7fa-bf51-a1a3-110f1bfdc73c@intel.com> References: <1480645311-13004-1-git-send-email-yamada.masahiro@socionext.com> <1480645311-13004-2-git-send-email-yamada.masahiro@socionext.com> Mime-Version: 1.0 Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit Return-path: Received: from mga01.intel.com ([192.55.52.88]:63902 "EHLO mga01.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S934341AbcLBOX6 (ORCPT ); Fri, 2 Dec 2016 09:23:58 -0500 In-Reply-To: <1480645311-13004-2-git-send-email-yamada.masahiro@socionext.com> Sender: linux-mmc-owner@vger.kernel.org List-Id: linux-mmc@vger.kernel.org To: Masahiro Yamada , linux-mmc@vger.kernel.org Cc: Ulf Hansson , linux-kernel@vger.kernel.org On 02/12/16 04:21, Masahiro Yamada wrote: > Some SDHCI-compat controllers support not only SD, but also eMMC, > but they use different commands for tuning: CMD19 for SD, CMD21 for > eMMC. > > Due to the difference of the underlying mechanism, some controllers > (at least, the Cadence IP is the case) provide their own registers > for the eMMC tuning. > > This commit will be useful when we want to use platform-specific > tuning (to support eMMC HS200), but still let it reuse the code > provided by sdhci_execute_tuning() for SD timing. > > If sdhci_ops::platform_execute_tuning receives a timing it does not > take care of, it can return -ENOTSUPP. Then, it will fall back to > the SDHCI standard tuning. > > Signed-off-by: Masahiro Yamada > --- > > I want to use this in the next commit. > > The Cadence IP supports eMMC as well as SD. > > The tuning for SD is pretty simple; just set the "Execute Tuning" bit > of the HOST_CONTROL2 register. So, I can re-use the > sdhci_execute_tuning(). > > On the other hand, Cadence provides its own way for eMMC HS200 tuning; > I need to touch some registers that are specific to Cadence's design. > > > Changes in v3: None > Changes in v2: None > > drivers/mmc/host/sdhci.c | 4 +++- > 1 file changed, 3 insertions(+), 1 deletion(-) > > diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c > index 42ef3eb..cdce489 100644 > --- a/drivers/mmc/host/sdhci.c > +++ b/drivers/mmc/host/sdhci.c > @@ -2004,7 +2004,9 @@ static int sdhci_execute_tuning(struct mmc_host *mmc, u32 opcode) > if (host->ops->platform_execute_tuning) { > spin_unlock_irqrestore(&host->lock, flags); > err = host->ops->platform_execute_tuning(host, opcode); > - return err; > + if (err != -ENOTSUPP) > + return err; > + spin_lock_irqsave(&host->lock, flags); platform_execute_tuning() should not exist. You could export sdhci_execute_tuning() and then provide your ->execute_tuning() (e.g. host->mmc_host_ops.execute_tuning = sdhci_cdns_execute_tuning) which can call sdhci_execute_tuning() if it needs to. > } > > ctrl = sdhci_readw(host, SDHCI_HOST_CONTROL2); >