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Message-ID: <CAPDyKFrT-45bz6_mbWXTKEe_JKfd+p4ava1RxZD=6CyCdTukOg@mail.gmail.com>
Date: Thu, 21 Jul 2022 12:58:36 +0200
From: Ulf Hansson <ulf.hansson@...aro.org>
To: Axe Yang <axe.yang@...iatek.com>,
Linus Walleij <linus.walleij@...aro.org>
Cc: Rob Herring <robh+dt@...nel.org>,
Chaotian Jing <chaotian.jing@...iatek.com>,
Matthias Brugger <matthias.bgg@...il.com>,
Adrian Hunter <adrian.hunter@...el.com>,
Yoshihiro Shimoda <yoshihiro.shimoda.uh@...esas.com>,
Satya Tangirala <satyat@...gle.com>,
Andy Shevchenko <andriy.shevchenko@...ux.intel.com>,
Wolfram Sang <wsa+renesas@...g-engineering.com>,
Lucas Stach <dev@...xeye.de>,
Eric Biggers <ebiggers@...gle.com>,
Andrew Jeffery <andrew@...id.au>,
Stephen Boyd <swboyd@...omium.org>,
Kiwoong Kim <kwmad.kim@...sung.com>,
Yue Hu <huyue2@...ong.com>, Tian Tao <tiantao6@...ilicon.com>,
angelogioacchino.delregno@...labora.com, linux-mmc@...r.kernel.org,
devicetree@...r.kernel.org, linux-kernel@...r.kernel.org,
linux-arm-kernel@...ts.infradead.org,
linux-mediatek@...ts.infradead.org,
Project_Global_Chrome_Upstream_Group@...iatek.com,
Yong Mao <yong.mao@...iatek.com>
Subject: Re: [PATCH v13 3/3] mmc: mediatek: add support for SDIO eint wakup IRQ
+ Linus Walleij
On Tue, 19 Jul 2022 at 12:35, Axe Yang <axe.yang@...iatek.com> wrote:
>
> On Mon, 2022-07-18 at 14:21 +0200, Ulf Hansson wrote:
> > On Thu, 23 Jun 2022 at 11:05, Axe Yang <axe.yang@...iatek.com> wrote:
> > >
> > > Add support for eint IRQ when MSDC is used as an SDIO host. This
> > > feature requires SDIO device support async IRQ function. With this
> > > feature, SDIO host can be awakened by SDIO card in suspend state,
> > > without additional pin.
> > >
> > > MSDC driver will time-share the SDIO DAT1 pin. During suspend, MSDC
> > > turn off clock and switch SDIO DAT1 pin to GPIO mode. And during
> > > resume, switch GPIO function back to DAT1 mode then turn on clock.
> > >
> > > Some device tree property should be added or modified in MSDC node
> > > to support SDIO eint IRQ. Pinctrls "state_eint" is mandatory. Since
> > > this feature depends on asynchronous interrupts, "wakeup-source",
> > > "keep-power-in-suspend" and "cap-sdio-irq" flags are necessary, and
> > > the interrupts list should be extended(the interrupt named with
> > > sdio_wakeup):
> > > &mmcX {
> > > ...
> > > interrupt-names = "msdc", "sdio_wakeup";
> > > interrupts-extended = <...>,
> > > <&pio xxx
> > > IRQ_TYPE_LEVEL_LOW>;
> > > ...
> > > pinctrl-names = "default", "state_uhs",
> > > "state_eint";
> > > ...
> > > pinctrl-2 = <&mmc2_pins_eint>;
> > > ...
> > > cap-sdio-irq;
> > > keep-power-in-suspend;
> > > wakeup-source;
> > > ...
> > > };
> > >
> > > Co-developed-by: Yong Mao <yong.mao@...iatek.com>
> > > Signed-off-by: Yong Mao <yong.mao@...iatek.com>
> > > Signed-off-by: Axe Yang <axe.yang@...iatek.com>
> >
> > My apologies for the delay in reviewing this.
>
> It is okay. Glad to receive your reply.
>
> >
> > > ---
> > > drivers/mmc/host/mtk-sd.c | 84
> > > ++++++++++++++++++++++++++++++++++++---
> > > 1 file changed, 78 insertions(+), 6 deletions(-)
> > >
> > > diff --git a/drivers/mmc/host/mtk-sd.c b/drivers/mmc/host/mtk-sd.c
> > > index 195dc897188b..f907b96cfd87 100644
> > > --- a/drivers/mmc/host/mtk-sd.c
> > > +++ b/drivers/mmc/host/mtk-sd.c
> > > @@ -1,6 +1,6 @@
> > > // SPDX-License-Identifier: GPL-2.0-only
> > > /*
> > > - * Copyright (c) 2014-2015 MediaTek Inc.
> > > + * Copyright (c) 2014-2015, 2022 MediaTek Inc.
> > > * Author: Chaotian.Jing <chaotian.jing@...iatek.com>
> > > */
> > >
> > > @@ -20,6 +20,7 @@
> > > #include <linux/platform_device.h>
> > > #include <linux/pm.h>
> > > #include <linux/pm_runtime.h>
> > > +#include <linux/pm_wakeirq.h>
> > > #include <linux/regulator/consumer.h>
> > > #include <linux/slab.h>
> > > #include <linux/spinlock.h>
> > > @@ -440,8 +441,10 @@ struct msdc_host {
> > > struct pinctrl *pinctrl;
> > > struct pinctrl_state *pins_default;
> > > struct pinctrl_state *pins_uhs;
> > > + struct pinctrl_state *pins_eint;
> > > struct delayed_work req_timeout;
> > > int irq; /* host interrupt */
> > > + int eint_irq; /* interrupt from sdio device for
> > > waking up system */
> > > struct reset_control *reset;
> > >
> > > struct clk *src_clk; /* msdc source clock */
> > > @@ -1520,17 +1523,46 @@ static void __msdc_enable_sdio_irq(struct
> > > msdc_host *host, int enb)
> > >
> > > static void msdc_enable_sdio_irq(struct mmc_host *mmc, int enb)
> > > {
> > > - unsigned long flags;
> > > struct msdc_host *host = mmc_priv(mmc);
> > > + unsigned long flags;
> > > + int ret;
> > >
> > > spin_lock_irqsave(&host->lock, flags);
> > > __msdc_enable_sdio_irq(host, enb);
> > > spin_unlock_irqrestore(&host->lock, flags);
> > >
> > > - if (enb)
> > > - pm_runtime_get_noresume(host->dev);
> > > - else
> > > - pm_runtime_put_noidle(host->dev);
> > > + if (mmc_card_enable_async_irq(mmc->card) && host-
> > > >pins_eint) {
> > > + if (enb) {
> > > + /*
> > > + * In
> > > dev_pm_set_dedicated_wake_irq_reverse(), eint pin will be set to
> > > + * GPIO mode. We need to restore it to SDIO
> > > DAT1 mode after that.
> > > + * Since the current pinstate is pins_uhs,
> > > to ensure pinctrl select take
> > > + * affect successfully, we change the
> > > pinstate to pins_eint firstly.
> > > + */
> > > + pinctrl_select_state(host->pinctrl, host-
> > > >pins_eint);
> >
> > I am sorry, but I don't understand what goes on here. Why do you need
> > to change the pinctrl setting to "pins_eint" here?
> >
> > The bellow call to dev_pm_set_dedicated_wake_irq_reverse() doesn't
> > change the pinctrl setting as the comment suggests above.
> >
>
> Actually, the pinctrl setting is changed:
> In dev_pm_set_dedicated_wake_irq_reverse() -> ... ->
> request_threaded_irq() -> __setup_irq() -> irq_request_resources() ->
> mtk_eint_irq_request_resources()-> mtk_xt_set_gpio_as_eint(), the SDIO
> DAT1 pin will be force reset to GPIO mode:
Aha. That looks a bit weird, but I get the problem now.
I have looped in Linus (the pintctrl maintainer) to get his opinion on this.
>
> https://elixir.bootlin.com/linux/latest/source/drivers/pinctrl/mediatek/pinctrl-mtk-common-v2.c#L339
>
> So, I have to call pinctrl_select_state() to restore SDIO DAT1 pin
> mode(pins_uhs). But pinctrl_select_state() return directly because MSDC
> driver still wrongly thinks current DAT1 state is SDIO DAT1 mode:
>
> https://elixir.bootlin.com/linux/latest/source/drivers/pinctrl/core.c#L1344
> , which means I have to call pinctrl_select_state() in pairs: Change
> pinctrl to another state(pins_eint), then change it back to pins_uhs
> mode.
I see. So a call to pinctrl_select_state("pins_uhs") would not take
effect, unless we call pinctrl_select_state("pins_eint") first. That
sounds like the internal state of the pinctrl isn't maintained
properly.
Let's see what Linus thinks about this.
Note that, I am happy to pick the patch as is around this, but I am
worried we might be doing something at the mmc driver level, which
should really be managed at the pinctrl layer.
>
>
> > dev_pm_set_dedicated_wake_irq_reverse() will register the wakeirq,
> > but
> > more importantly, it should also leave the wakeirq disabled, right?
>
> Yes. wakeirq will be registered, and disabled. But SDIO DAT1 pin mode
> will be changed too.
>
> >
> > > + ret =
> > > dev_pm_set_dedicated_wake_irq_reverse(host->dev, host->eint_irq);
> > > +
> > > + if (ret) {
> > > + dev_err(host->dev, "Failed to
> > > register SDIO wakeup irq!\n");
> > > + host->pins_eint = NULL;
> > > + pm_runtime_get_noresume(host->dev);
> > > + } else {
> > > + dev_dbg(host->dev, "SDIO eint irq:
> > > %d!\n", host->eint_irq);
> > > + }
> > > +
> > > + pinctrl_select_state(host->pinctrl, host-
> > > >pins_uhs);
> >
> > According to my comment above, I also don't understand why you need
> > this. Why can't you just leave the pinctrl in the "pins_uhs" state?
> >
> I have to call pinctrl_select_state() in pairs.
>
>
> > > + } else {
> > > + dev_pm_clear_wake_irq(host->dev);
> > > + }
> > > + } else {
> > > + if (enb) {
> > > + /* Ensure host->pins_eint is NULL */
> > > + host->pins_eint = NULL;
> > > + pm_runtime_get_noresume(host->dev);
> > > + } else {
> > > + pm_runtime_put_noidle(host->dev);
> > > + }
> > > + }
> > > }
[...]
Kind regards
Uffe
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