Messages in this thread | | | Date | Fri, 18 Sep 2020 15:38:43 +0900 | From | AKASHI Takahiro <> | Subject | Re: [RFC PATCH V3 12/21] mmc: sdhci: UHS-II support, add hooks for additional operations |
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Adrian, Ben,
Regarding _set_ios() function,
On Fri, Aug 21, 2020 at 05:08:32PM +0300, Adrian Hunter wrote: > On 10/07/20 2:10 pm, Ben Chuang wrote: > > From: Ben Chuang <ben.chuang@genesyslogic.com.tw> > > > > In this commit, UHS-II related operations will be called via a function > > pointer array, sdhci_uhs2_ops, in order to make UHS-II support as > > a kernel module. > > This array will be initialized only if CONFIG_MMC_SDHCI_UHS2 is enabled > > and when the UHS-II module is loaded. Otherwise, all the functions > > stay void. > > > > Signed-off-by: Ben Chuang <ben.chuang@genesyslogic.com.tw> > > Signed-off-by: AKASHI Takahiro <takahiro.akashi@linaro.org>
(snip)
> > @@ -2261,6 +2324,7 @@ void sdhci_set_ios(struct mmc_host *mmc, struct mmc_ios *ios) > > { > > struct sdhci_host *host = mmc_priv(mmc); > > u8 ctrl; > > + u16 ctrl_2; > > > > if (ios->power_mode == MMC_POWER_UNDEFINED) > > return; > > @@ -2287,6 +2351,10 @@ void sdhci_set_ios(struct mmc_host *mmc, struct mmc_ios *ios) > > sdhci_enable_preset_value(host, false); > > > > if (!ios->clock || ios->clock != host->clock) { > > + if (IS_ENABLED(CONFIG_MMC_SDHCI_UHS2) && > > + ios->timing == MMC_TIMING_UHS2) > > + host->timing = ios->timing; > > + > > host->ops->set_clock(host, ios->clock); > > host->clock = ios->clock; > > > > @@ -2308,6 +2376,18 @@ void sdhci_set_ios(struct mmc_host *mmc, struct mmc_ios *ios) > > else > > sdhci_set_power(host, ios->power_mode, ios->vdd); > > > > + /* 4.0 host support */ > > + if (host->version >= SDHCI_SPEC_400) { > > + /* UHS2 Support */ > > + if (IS_ENABLED(CONFIG_MMC_SDHCI_UHS2) && > > + host->mmc->flags & MMC_UHS2_SUPPORT && > > + host->mmc->caps & MMC_CAP_UHS2) { > > + if (sdhci_uhs2_ops.do_set_ios) > > + sdhci_uhs2_ops.do_set_ios(host, ios); > > + return; > > + } > > + } > > + > > Please look at using existing callbacks instead, maybe creating uhs2_set_ios(), uhs2_set_clock(), uhs2_set_power()
I think that we will create uhs2_set_ios() (and uhs2_set_power() as we discussed on patch#15/21), but not uhs_set_clock().
Since we have a hook only in struct mmc_host_ops, but not in struct sdhci_ops, all the drivers who want to support UHS-II need to set host->mmc_host_ops->set_ios to sdhci_uhs2_set_ios explicitly in their own init (or probe) function. (Again, sdhci_uhs2_set_ios() seems to be generic though.)
Is this okay for you? -> Adrian
During refactoring the code, I found that sdhci_set_power() is called twice in sdhci_set_ios(): sdhci_set_ios(host, power_mode, vdd1, -1); in sdhci_set_ios(), and sdhci_set_ios(host, power_mode, vdd1, vdd2) in ush2_do_set_ios()
Can you please confirm that those are redundant? -> Ben
I also wonder why we need spin locks in uhs2_do_set_ios() while not in sdhci_set_ios().
-> Ben
-Takahiro Akashi
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