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SubjectRe: [PATCH 8/9] mmc: mmci: sdmmc: add voltage switch functions
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hi Ulf

Le 1/24/20 à 2:16 PM, Ulf Hansson a écrit :
> On Fri, 10 Jan 2020 at 14:49, Ludovic Barre <ludovic.barre@st.com> wrote:
>>
>> To prepare the voltage switch procedure, the VSWITCHEN bit must be
>> set before sending the cmd11.
>> To confirm completion of voltage switch, the VSWEND flag must be
>> checked.
>>
>> Signed-off-by: Ludovic Barre <ludovic.barre@st.com>
>> ---
>> drivers/mmc/host/mmci.h | 4 +++
>> drivers/mmc/host/mmci_stm32_sdmmc.c | 40 ++++++++++++++++++++++++++++-
>> 2 files changed, 43 insertions(+), 1 deletion(-)
>>
>> diff --git a/drivers/mmc/host/mmci.h b/drivers/mmc/host/mmci.h
>> index c04a144259a2..3634f98ad2d8 100644
>> --- a/drivers/mmc/host/mmci.h
>> +++ b/drivers/mmc/host/mmci.h
>> @@ -165,6 +165,7 @@
>> /* Extended status bits for the STM32 variants */
>> #define MCI_STM32_BUSYD0 BIT(20)
>> #define MCI_STM32_BUSYD0END BIT(21)
>> +#define MCI_STM32_VSWEND BIT(25)
>>
>> #define MMCICLEAR 0x038
>> #define MCI_CMDCRCFAILCLR (1 << 0)
>> @@ -182,6 +183,9 @@
>> #define MCI_ST_SDIOITC (1 << 22)
>> #define MCI_ST_CEATAENDC (1 << 23)
>> #define MCI_ST_BUSYENDC (1 << 24)
>> +/* Extended clear bits for the STM32 variants */
>> +#define MCI_STM32_VSWENDC BIT(25)
>> +#define MCI_STM32_CKSTOPC BIT(26)
>>
>> #define MMCIMASK0 0x03c
>> #define MCI_CMDCRCFAILMASK (1 << 0)
>> diff --git a/drivers/mmc/host/mmci_stm32_sdmmc.c b/drivers/mmc/host/mmci_stm32_sdmmc.c
>> index 10059fa19f4a..9f43cf947c5f 100644
>> --- a/drivers/mmc/host/mmci_stm32_sdmmc.c
>> +++ b/drivers/mmc/host/mmci_stm32_sdmmc.c
>> @@ -263,7 +263,9 @@ static void mmci_sdmmc_set_pwrreg(struct mmci_host *host, unsigned int pwr)
>> struct mmc_ios ios = host->mmc->ios;
>> struct sdmmc_dlyb *dlyb = host->variant_priv;
>>
>> - pwr = host->pwr_reg_add;
>> + /* adds OF options and preserves voltage switch bits */
>> + pwr = host->pwr_reg_add |
>> + (host->pwr_reg & (MCI_STM32_VSWITCHEN | MCI_STM32_VSWITCH));
>>
>> sdmmc_dlyb_input_ck(dlyb);
>>
>> @@ -454,6 +456,40 @@ static int sdmmc_execute_tuning(struct mmc_host *mmc, u32 opcode)
>> return sdmmc_dlyb_phase_tuning(host, opcode);
>> }
>>
>> +static void sdmmc_prep_vswitch(struct mmci_host *host)
>> +{
>> + /* clear the voltage switch completion flag */
>> + writel_relaxed(MCI_STM32_VSWENDC, host->base + MMCICLEAR);
>> + /* enable Voltage switch procedure */
>> + mmci_write_pwrreg(host, host->pwr_reg | MCI_STM32_VSWITCHEN);
>> +}
>> +
>> +static int sdmmc_vswitch(struct mmci_host *host, struct mmc_ios *ios)
>> +{
>> + unsigned long flags;
>> + u32 status;
>> + int ret = 0;
>> +
>> + if (ios->signal_voltage == MMC_SIGNAL_VOLTAGE_180) {
>> + spin_lock_irqsave(&host->lock, flags);
>> + mmci_write_pwrreg(host, host->pwr_reg | MCI_STM32_VSWITCH);
>> + spin_unlock_irqrestore(&host->lock, flags);
>> +
>> + /* wait voltage switch completion while 10ms */
>> + ret = readl_relaxed_poll_timeout(host->base + MMCISTATUS,
>> + status,
>> + (status & MCI_STM32_VSWEND),
>> + 10, 10000);
>> +
>> + writel_relaxed(MCI_STM32_VSWENDC | MCI_STM32_CKSTOPC,
>> + host->base + MMCICLEAR);
>> + mmci_write_pwrreg(host, host->pwr_reg &
>> + ~(MCI_STM32_VSWITCHEN | MCI_STM32_VSWITCH));
>> + }
>
> Don't you need to manage things when resetting to
> MMC_SIGNAL_VOLTAGE_330, which for example happens during a card
> removal or at system suspend/resume?
>

The VSWITCH sequence is used only for 3.3V to 1.8V.
If there are: card remove | suspend/resume.
The power cycle of sdmmc must be reinitialised
and the reset is mandatory.

>> +
>> + return ret;
>> +}
>> +
>> static struct mmci_host_ops sdmmc_variant_ops = {
>> .validate_data = sdmmc_idma_validate_data,
>> .prep_data = sdmmc_idma_prep_data,
>> @@ -465,6 +501,8 @@ static struct mmci_host_ops sdmmc_variant_ops = {
>> .set_clkreg = mmci_sdmmc_set_clkreg,
>> .set_pwrreg = mmci_sdmmc_set_pwrreg,
>> .busy_complete = sdmmc_busy_complete,
>> + .prep_volt_switch = sdmmc_prep_vswitch,
>> + .volt_switch = sdmmc_vswitch,
>> };
>>
>> void sdmmc_variant_init(struct mmci_host *host)
>> --
>> 2.17.1
>>
>
> Kind regards
> Uffe
>

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