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SubjectRe: [PATCH RESEND] mmc: mmci: manage MMC_PM_KEEP_POWER per variant config
On Mon, 14 Mar 2022 at 10:53, Yann Gautier <yann.gautier@foss.st.com> wrote:
>
> Add a disable_keep_power field in variant_data struct. The
> MMC_PM_KEEP_POWER flag will be enabled if disable_keep_power is not set.
> It is only set to true for stm32_sdmmc variants.
>
> The issue was seen on STM32MP157C-DK2 board, which embeds a wifi chip.
> It doesn't correctly support low power, and we need to unbind the wifi
> driver before a suspend sequence. But the wifi chip firmware is then
> lost, and the communication with SDIO fails if MMC_PM_KEEP_POWER is
> enabled.

So the platform supports to maintain the power for the embedded wifi
chip during system suspend, but the SDIO func driver (for the WiFi
chip) doesn't implement its part correctly. Did I get that right?

In that case, it sounds to me like we should try to fix the support
for power management in the SDIO func driver instead, no?
I am happy to help with guidance/review if that is needed. What SDIO
func driver is this about?

Kind regards
Uffe

> The flag can still be enabled through DT property: keep-power-in-suspend.
>
> Signed-off-by: Yann Gautier <yann.gautier@foss.st.com>
> ---
> Resend the patch alone. It was previoulsy in a series [1] for which the
> other patches will be reworked.
>
> [1] https://lore.kernel.org/lkml/20220304135134.47827-1-yann.gautier@foss.st.com/
>
> drivers/mmc/host/mmci.c | 5 ++++-
> drivers/mmc/host/mmci.h | 1 +
> 2 files changed, 5 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/mmc/host/mmci.c b/drivers/mmc/host/mmci.c
> index 45b8608c935c..0e2f2f5d6a52 100644
> --- a/drivers/mmc/host/mmci.c
> +++ b/drivers/mmc/host/mmci.c
> @@ -274,6 +274,7 @@ static struct variant_data variant_stm32_sdmmc = {
> .busy_detect = true,
> .busy_detect_flag = MCI_STM32_BUSYD0,
> .busy_detect_mask = MCI_STM32_BUSYD0ENDMASK,
> + .disable_keep_power = true,
> .init = sdmmc_variant_init,
> };
>
> @@ -301,6 +302,7 @@ static struct variant_data variant_stm32_sdmmcv2 = {
> .busy_detect = true,
> .busy_detect_flag = MCI_STM32_BUSYD0,
> .busy_detect_mask = MCI_STM32_BUSYD0ENDMASK,
> + .disable_keep_power = true,
> .init = sdmmc_variant_init,
> };
>
> @@ -2172,7 +2174,8 @@ static int mmci_probe(struct amba_device *dev,
> host->stop_abort.flags = MMC_RSP_R1B | MMC_CMD_AC;
>
> /* We support these PM capabilities. */
> - mmc->pm_caps |= MMC_PM_KEEP_POWER;
> + if (!variant->disable_keep_power)
> + mmc->pm_caps |= MMC_PM_KEEP_POWER;
>
> /*
> * We can do SGIO
> diff --git a/drivers/mmc/host/mmci.h b/drivers/mmc/host/mmci.h
> index e1a9b96a3396..2cad1ef9766a 100644
> --- a/drivers/mmc/host/mmci.h
> +++ b/drivers/mmc/host/mmci.h
> @@ -361,6 +361,7 @@ struct variant_data {
> u32 opendrain;
> u8 dma_lli:1;
> u32 stm32_idmabsize_mask;
> + u8 disable_keep_power:1;
> void (*init)(struct mmci_host *host);
> };
>
> --
> 2.25.1
>

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