Re: [RFC PATCH v3.1 16/27] mmc: sdhci-uhs2: add set_ios()

Adrian Hunter
2020-12-03T09:52:30Z

On 30/11/20 9:51 am, AKASHI Takahiro wrote:
> On Thu, Nov 26, 2020 at 10:17:11AM +0200, Adrian Hunter wrote:
>> On 6/11/20 4:27 am, AKASHI Takahiro wrote:
>>> This is a sdhci version of mmc's set_ios operation.
>>> It covers both UHS-I and UHS-II.
>>>
>>> Signed-off-by: Ben Chuang <ben.chuang@genesyslogic.com.tw>
>>> Signed-off-by: AKASHI Takahiro <takahiro.akashi@linaro.org>
>>> ---
>>> drivers/mmc/host/sdhci-uhs2.c | 100 ++++++++++++++++++++++++++++++++++
>>> drivers/mmc/host/sdhci-uhs2.h | 1 +
>>> drivers/mmc/host/sdhci.c | 40 +++++++++-----
>>> drivers/mmc/host/sdhci.h | 2 +
>>> 4 files changed, 128 insertions(+), 15 deletions(-)
>>>
>>> diff --git a/drivers/mmc/host/sdhci-uhs2.c b/drivers/mmc/host/sdhci-uhs2.c
>>> index d9e98c097bfe..637464748cc4 100644
>>> --- a/drivers/mmc/host/sdhci-uhs2.c
>>> +++ b/drivers/mmc/host/sdhci-uhs2.c
>>> @@ -263,6 +263,74 @@ void sdhci_uhs2_set_timeout(struct sdhci_host *host, struct mmc_command *cmd)
>>> }
>>> EXPORT_SYMBOL_GPL(sdhci_uhs2_set_timeout);
>>>
>>> +/**
>>> + * sdhci_uhs2_clear_set_irqs - set Error Interrupt Status Enable register
>>> + * @host: SDHCI host
>>> + * @clear: bit-wise clear mask
>>> + * @set: bit-wise set mask
>>> + *
>>> + * Set/unset bits in UHS-II Error Interrupt Status Enable register
>>> + */
>>> +void sdhci_uhs2_clear_set_irqs(struct sdhci_host *host, u32 clear, u32 set)
>>> +{
>>> + u32 ier;
>>> +
>>> + ier = sdhci_readl(host, SDHCI_UHS2_ERR_INT_STATUS_EN);
>>> + ier &= ~clear;
>>> + ier |= set;
>>> + sdhci_writel(host, ier, SDHCI_UHS2_ERR_INT_STATUS_EN);
>>> + sdhci_writel(host, ier, SDHCI_UHS2_ERR_INT_SIG_EN);
>>> +}
>>> +EXPORT_SYMBOL_GPL(sdhci_uhs2_clear_set_irqs);
>>> +
>>> +static void __sdhci_uhs2_set_ios(struct mmc_host *mmc, struct mmc_ios *ios)
>>> +{
>>> + struct sdhci_host *host = mmc_priv(mmc);
>>> + u8 cmd_res, dead_lock;
>>> + u16 ctrl_2;
>>> + unsigned long flags;
>>> +
>>> + /* FIXME: why lock? */
>>> + spin_lock_irqsave(&host->lock, flags);
>>> +
>>> + /* UHS2 Timeout Control */
>>> + sdhci_calc_timeout_uhs2(host, &cmd_res, &dead_lock);
>>> +
>>> + /* change to use calculate value */
>>> + cmd_res |= dead_lock << SDHCI_UHS2_TIMER_CTRL_DEADLOCK_SHIFT;
>>> +
>>> + sdhci_uhs2_clear_set_irqs(host,
>>> + SDHCI_UHS2_ERR_INT_STATUS_RES_TIMEOUT |
>>> + SDHCI_UHS2_ERR_INT_STATUS_DEADLOCK_TIMEOUT,
>>> + 0);
>>> + sdhci_writeb(host, cmd_res, SDHCI_UHS2_TIMER_CTRL);
>>> + sdhci_uhs2_clear_set_irqs(host, 0,
>>> + SDHCI_UHS2_ERR_INT_STATUS_RES_TIMEOUT |
>>> + SDHCI_UHS2_ERR_INT_STATUS_DEADLOCK_TIMEOUT);
>>> +
>>> + /* UHS2 timing */
>>> + ctrl_2 = sdhci_readw(host, SDHCI_HOST_CONTROL2);
>>> + if (ios->timing == MMC_TIMING_UHS2)
>>> + ctrl_2 |= SDHCI_CTRL_UHS_2 | SDHCI_CTRL_UHS2_INTERFACE_EN;
>>> + else
>>> + ctrl_2 &= ~(SDHCI_CTRL_UHS_2 | SDHCI_CTRL_UHS2_INTERFACE_EN);
>>> + sdhci_writew(host, ctrl_2, SDHCI_HOST_CONTROL2);
>>> +
>>> + if (!(host->quirks2 & SDHCI_QUIRK2_PRESET_VALUE_BROKEN))
>>> + sdhci_enable_preset_value(host, true);
>>> +
>>> + if (host->ops->set_power)
>>> + host->ops->set_power(host, ios->power_mode, ios->vdd);
>>> + else
>>> + sdhci_set_power(host, ios->power_mode, ios->vdd);
>>> + udelay(100);
>>> +
>>> + host->timing = ios->timing;
>>> + sdhci_set_clock(host, host->clock);
>>
>> sdhci_set_ios_common() already called ->set_clock() and ->set_power(), so I
>> am not really following what is going on here. Can you explain some more?
>
> To be frank, I don't know. The logic in Intel's (and/or Ben's?)
> original code does so.
> What I changed is to remove the code of setting (ios->vdd and) ios->vdd2,
> which is executed before calling set_power(), in __sdhci_uhs2_set_ios().
>
> So yes, effectively it may be of no use to call set_power() here.

Please try to rationalize it. Also set_ios() should not need the spin lock,
and that allows clock and power callbacks to sleep if needed.

>
> -Takahiro Akashi
>
>>> +
>>> + spin_unlock_irqrestore(&host->lock, flags);
>>> +}
>>> +
>>> /*****************************************************************************\
>>> * *
>>> * MMC callbacks *
>>> @@ -286,6 +354,37 @@ static int sdhci_uhs2_start_signal_voltage_switch(struct mmc_host *mmc,
>>> return sdhci_start_signal_voltage_switch(mmc, ios);
>>> }
>>>
>>> +void sdhci_uhs2_set_ios(struct mmc_host *mmc, struct mmc_ios *ios)
>>> +{
>>> + struct sdhci_host *host = mmc_priv(mmc);
>>> +
>>> + if (!(host->version >= SDHCI_SPEC_400) ||
>>> + !(host->mmc->flags & MMC_UHS2_SUPPORT &&
>>> + host->mmc->caps & MMC_CAP_UHS2)) {
>>> + sdhci_set_ios(mmc, ios);
>>> + return;
>>> + }
>>> +
>>> + if (ios->power_mode == MMC_POWER_UNDEFINED)
>>> + return;
>>> +
>>> + if (host->flags & SDHCI_DEVICE_DEAD) {
>>> + if (!IS_ERR(mmc->supply.vmmc) &&
>>> + ios->power_mode == MMC_POWER_OFF)
>>> + mmc_regulator_set_ocr(mmc, mmc->supply.vmmc, 0);
>>> + if (!IS_ERR_OR_NULL(mmc->supply.vmmc2) &&
>>> + ios->power_mode == MMC_POWER_OFF)
>>> + mmc_regulator_set_ocr(mmc, mmc->supply.vmmc2, 0);
>>> + return;
>>> + }
>>> +
>>> + /* FIXME: host->timing = ios->timing */
>>> +
>>> + sdhci_set_ios_common(mmc, ios);
>>> +
>>> + __sdhci_uhs2_set_ios(mmc, ios);
>>> +}
>>> +
>>> /*****************************************************************************\
>>> * *
>>> * Driver init/exit *
>>> @@ -296,6 +395,7 @@ static int sdhci_uhs2_host_ops_init(struct sdhci_host *host)
>>> {
>>> host->mmc_host_ops.start_signal_voltage_switch =
>>> sdhci_uhs2_start_signal_voltage_switch;
>>> + host->mmc_host_ops.set_ios = sdhci_uhs2_set_ios;
>>>
>>> return 0;
>>> }
>>> diff --git a/drivers/mmc/host/sdhci-uhs2.h b/drivers/mmc/host/sdhci-uhs2.h
>>> index efe70577bc74..c1ff4ac1ab7a 100644
>>> --- a/drivers/mmc/host/sdhci-uhs2.h
>>> +++ b/drivers/mmc/host/sdhci-uhs2.h
>>> @@ -214,5 +214,6 @@ void sdhci_uhs2_reset(struct sdhci_host *host, u16 mask);
>>> void sdhci_uhs2_set_power(struct sdhci_host *host, unsigned char mode,
>>> unsigned short vdd);
>>> void sdhci_uhs2_set_timeout(struct sdhci_host *host, struct mmc_command *cmd);
>>> +void sdhci_uhs2_clear_set_irqs(struct sdhci_host *host, u32 clear, u32 set);
>>>
>>> #endif /* __SDHCI_UHS2_H */
>>> diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c
>>> index 0b741eb546cb..becb228330af 100644
>>> --- a/drivers/mmc/host/sdhci.c
>>> +++ b/drivers/mmc/host/sdhci.c
>>> @@ -48,8 +48,6 @@
>>> static unsigned int debug_quirks = 0;
>>> static unsigned int debug_quirks2;
>>>
>>> -static void sdhci_enable_preset_value(struct sdhci_host *host, bool enable);
>>> -
>>> static bool sdhci_send_command(struct sdhci_host *host, struct mmc_command *cmd);
>>>
>>> void sdhci_dumpregs(struct sdhci_host *host)
>>> @@ -1836,6 +1834,9 @@ static u16 sdhci_get_preset_value(struct sdhci_host *host)
>>> case MMC_TIMING_MMC_HS400:
>>> preset = sdhci_readw(host, SDHCI_PRESET_FOR_HS400);
>>> break;
>>> + case MMC_TIMING_UHS2:
>>> + preset = sdhci_readw(host, SDHCI_PRESET_FOR_UHS2);
>>> + break;
>>> default:
>>> pr_warn("%s: Invalid UHS-I mode selected\n",
>>> mmc_hostname(host->mmc));
>>> @@ -2249,20 +2250,9 @@ void sdhci_set_uhs_signaling(struct sdhci_host *host, unsigned timing)
>>> }
>>> EXPORT_SYMBOL_GPL(sdhci_set_uhs_signaling);
>>>
>>> -void sdhci_set_ios(struct mmc_host *mmc, struct mmc_ios *ios)
>>> +void sdhci_set_ios_common(struct mmc_host *mmc, struct mmc_ios *ios)
>>> {
>>> struct sdhci_host *host = mmc_priv(mmc);
>>> - u8 ctrl;
>>> -
>>> - if (ios->power_mode == MMC_POWER_UNDEFINED)
>>> - return;
>>> -
>>> - if (host->flags & SDHCI_DEVICE_DEAD) {
>>> - if (!IS_ERR(mmc->supply.vmmc) &&
>>> - ios->power_mode == MMC_POWER_OFF)
>>> - mmc_regulator_set_ocr(mmc, mmc->supply.vmmc, 0);
>>> - return;
>>> - }
>>>
>>> /*
>>> * Reset the chip on each power off.
>>> @@ -2299,6 +2289,25 @@ void sdhci_set_ios(struct mmc_host *mmc, struct mmc_ios *ios)
>>> host->ops->set_power(host, ios->power_mode, ios->vdd);
>>> else
>>> sdhci_set_power(host, ios->power_mode, ios->vdd);
>>> +}
>>> +EXPORT_SYMBOL_GPL(sdhci_set_ios_common);
>>> +
>>> +void sdhci_set_ios(struct mmc_host *mmc, struct mmc_ios *ios)
>>> +{
>>> + struct sdhci_host *host = mmc_priv(mmc);
>>> + u8 ctrl;
>>> +
>>> + if (ios->power_mode == MMC_POWER_UNDEFINED)
>>> + return;
>>> +
>>> + if (host->flags & SDHCI_DEVICE_DEAD) {
>>> + if (!IS_ERR(mmc->supply.vmmc) &&
>>> + ios->power_mode == MMC_POWER_OFF)
>>> + mmc_regulator_set_ocr(mmc, mmc->supply.vmmc, 0);
>>> + return;
>>> + }
>>> +
>>> + sdhci_set_ios_common(mmc, ios);
>>>
>>> if (host->ops->platform_send_init_74_clocks)
>>> host->ops->platform_send_init_74_clocks(host, ios->power_mode);
>>> @@ -2869,7 +2878,7 @@ int sdhci_execute_tuning(struct mmc_host *mmc, u32 opcode)
>>> }
>>> EXPORT_SYMBOL_GPL(sdhci_execute_tuning);
>>>
>>> -static void sdhci_enable_preset_value(struct sdhci_host *host, bool enable)
>>> +void sdhci_enable_preset_value(struct sdhci_host *host, bool enable)
>>> {
>>> /* Host Controller v3.00 defines preset value registers */
>>> if (host->version < SDHCI_SPEC_300)
>>> @@ -2897,6 +2906,7 @@ static void sdhci_enable_preset_value(struct sdhci_host *host, bool enable)
>>> host->preset_enabled = enable;
>>> }
>>> }
>>> +EXPORT_SYMBOL_GPL(sdhci_enable_preset_value);
>>>
>>> static void sdhci_post_req(struct mmc_host *mmc, struct mmc_request *mrq,
>>> int err)
>>> diff --git a/drivers/mmc/host/sdhci.h b/drivers/mmc/host/sdhci.h
>>> index 2b5b8295cf92..e84ebddb20d8 100644
>>> --- a/drivers/mmc/host/sdhci.h
>>> +++ b/drivers/mmc/host/sdhci.h
>>> @@ -851,6 +851,8 @@ void sdhci_set_bus_width(struct sdhci_host *host, int width);
>>> void sdhci_reset(struct sdhci_host *host, u8 mask);
>>> void sdhci_set_uhs_signaling(struct sdhci_host *host, unsigned timing);
>>> int sdhci_execute_tuning(struct mmc_host *mmc, u32 opcode);
>>> +void sdhci_enable_preset_value(struct sdhci_host *host, bool enable);
>>> +void sdhci_set_ios_common(struct mmc_host *mmc, struct mmc_ios *ios);
>>> void sdhci_set_ios(struct mmc_host *mmc, struct mmc_ios *ios);
>>> int sdhci_start_signal_voltage_switch(struct mmc_host *mmc,
>>> struct mmc_ios *ios);
>>>
>>