| Message ID | 878da006-5b83-a9d9-6136-07d8f07ea65f@intel.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
Hi Adrian, Thanks a lot for your suggestion. I have sent out the new version patch-set. Please help to review :) Best regards, Yangbo Lu > -----Original Message----- > From: Adrian Hunter [mailto:adrian.hunter@intel.com] > Sent: Thursday, March 23, 2017 3:04 PM > To: Y.B. Lu; linux-mmc@vger.kernel.org; ulf.hansson@linaro.org; Rob > Herring; Mark Rutland; Catalin Marinas; Will Deacon > Cc: devicetree@vger.kernel.org; linux-arm-kernel@lists.infradead.org; > Xiaobo Xie > Subject: Re: [v2, 4/7] mmc: sdhci: add a quirk to restore delay in tuning > > On 03/03/17 10:18, Yangbo Lu wrote: > > There was a mdelay between tuning cycles which is removed since eMMC > > spec didn't require that. However it's observed that eSDHC needed this > > delay for HS200 successful tuning. Maybe it's also needed for some > > other controllers. This patch is to add a quirk to fix it. > > > > Fixes: 197160d52e85 ("mmc: sdhci: remove mdelay in eMMC tuning") > > Signed-off-by: Yangbo Lu <yangbo.lu@nxp.com> > > --- > > I would prefer to do something like this: > > --- > From: Adrian Hunter <adrian.hunter@intel.com> > Date: Thu, 23 Mar 2017 08:54:06 +0200 > Subject: [PATCH] mmc: sdhci: Control the delay between tuning commands > > The delay between tuning commands for SD cards is not part of the > specification. A driver that needs it probably needs it for eMMC too, > whereas most drivers would probably like to set it to 0. Make it a host > member (host->tuning_delay) that defaults to the existing behaviour. > Drivers can set it to zero to eliminate the delay, or set it to a > positive value to always have a delay. > > Signed-off-by: Adrian Hunter <adrian.hunter@intel.com> > --- > drivers/mmc/host/sdhci.c | 11 ++++++++--- drivers/mmc/host/sdhci.h | 1 > + > 2 files changed, 9 insertions(+), 3 deletions(-) > > diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c index > a33102fc800b..2fc33485df1d 100644 > --- a/drivers/mmc/host/sdhci.c > +++ b/drivers/mmc/host/sdhci.c > @@ -2100,9 +2100,9 @@ static void __sdhci_execute_tuning(struct > sdhci_host *host, u32 opcode) > break; > } > > - /* eMMC spec does not require a delay between tuning cycles > */ > - if (opcode == MMC_SEND_TUNING_BLOCK) > - mdelay(1); > + /* Spec does not require a delay between tuning cycles */ > + if (host->tuning_delay > 0) > + mdelay(host->tuning_delay); > } > > pr_info("%s: Tuning failed, falling back to fixed sampling clock\n", > @@ -2164,6 +2164,9 @@ int sdhci_execute_tuning(struct mmc_host *mmc, u32 > opcode) > > host->mmc->retune_period = tuning_count; > > + if (host->tuning_delay < 0) > + host->tuning_delay = opcode == MMC_SEND_TUNING_BLOCK; > + > sdhci_start_tuning(host); > > __sdhci_execute_tuning(host, opcode); > @@ -3108,6 +3111,8 @@ struct sdhci_host *sdhci_alloc_host(struct device > *dev, > host->cqe_ier = SDHCI_CQE_INT_MASK; > host->cqe_err_ier = SDHCI_CQE_INT_ERR_MASK; > > + host->tuning_delay = -1; > + > return host; > } > > diff --git a/drivers/mmc/host/sdhci.h b/drivers/mmc/host/sdhci.h index > 35b41da0a636..b0f416fc9548 100644 > --- a/drivers/mmc/host/sdhci.h > +++ b/drivers/mmc/host/sdhci.h > @@ -538,6 +538,7 @@ struct sdhci_host { > #define SDHCI_TUNING_MODE_1 0 > #define SDHCI_TUNING_MODE_2 1 > #define SDHCI_TUNING_MODE_3 2 > + int tuning_delay; /* Delay (ms) between tuning > commands */ > > unsigned long private[0] ____cacheline_aligned; }; > -- > 1.9.1 > >
diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c index a33102fc800b..2fc33485df1d 100644 --- a/drivers/mmc/host/sdhci.c +++ b/drivers/mmc/host/sdhci.c @@ -2100,9 +2100,9 @@ static void __sdhci_execute_tuning(struct sdhci_host *host, u32 opcode) break; } - /* eMMC spec does not require a delay between tuning cycles */ - if (opcode == MMC_SEND_TUNING_BLOCK) - mdelay(1); + /* Spec does not require a delay between tuning cycles */ + if (host->tuning_delay > 0) + mdelay(host->tuning_delay); } pr_info("%s: Tuning failed, falling back to fixed sampling clock\n", @@ -2164,6 +2164,9 @@ int sdhci_execute_tuning(struct mmc_host *mmc, u32 opcode) host->mmc->retune_period = tuning_count; + if (host->tuning_delay < 0) + host->tuning_delay = opcode == MMC_SEND_TUNING_BLOCK; + sdhci_start_tuning(host); __sdhci_execute_tuning(host, opcode); @@ -3108,6 +3111,8 @@ struct sdhci_host *sdhci_alloc_host(struct device *dev, host->cqe_ier = SDHCI_CQE_INT_MASK; host->cqe_err_ier = SDHCI_CQE_INT_ERR_MASK; + host->tuning_delay = -1; + return host; } diff --git a/drivers/mmc/host/sdhci.h b/drivers/mmc/host/sdhci.h index 35b41da0a636..b0f416fc9548 100644 --- a/drivers/mmc/host/sdhci.h +++ b/drivers/mmc/host/sdhci.h @@ -538,6 +538,7 @@ struct sdhci_host { #define SDHCI_TUNING_MODE_1 0 #define SDHCI_TUNING_MODE_2 1 #define SDHCI_TUNING_MODE_3 2 + int tuning_delay; /* Delay (ms) between tuning commands */ unsigned long private[0] ____cacheline_aligned; };