Re: [PATCH v2 4/4] can: flexcan: add wakeup support for imx95

From: Frank Li
Date: Tue Jul 16 2024 - 10:46:22 EST

On Tue, Jul 16, 2024 at 09:06:14AM +0200, Marc Kleine-Budde wrote:
> On 15.07.2024 17:27:23, Frank Li wrote:
> > From: Haibo Chen <haibo.chen@xxxxxxx>
> >
> > iMX95 defines a bit in GPR that sets/unsets the IPG_STOP signal to the
> > FlexCAN module, controlling its entry into STOP mode. Wakeup should work
> > even if FlexCAN is in STOP mode.
> >
> > Due to iMX95 architecture design, the A-Core cannot access GPR; only the
> > system manager (SM) can configure GPR. To support the wakeup feature,
> > follow these steps:
> >
> > - For suspend:
> > 1) During Linux suspend, when CAN suspends, do nothing for GPR and keep
> > CAN-related clocks on.
> > 2) In ATF, check whether CAN needs to support wakeup; if yes, send a
> > request to SM through the SCMI protocol.
> > 3) In SM, configure the GPR and unset IPG_STOP.
> > 4) A-Core suspends.
> >
> > - For wakeup and resume:
> > 1) A-Core wakeup event arrives.
> > 2) In SM, deassert IPG_STOP.
> > 3) Linux resumes.
> >
> > Add a new fsl_imx95_devtype_data and FLEXCAN_QUIRK_SETUP_STOP_MODE_SCMI to
> > reflect this.
> >
> > Reviewed-by: Han Xu <han.xu@xxxxxxx>
> > Signed-off-by: Haibo Chen <haibo.chen@xxxxxxx>
> > Reviewed-by: Vincent Mailhol <mailhol.vincent@xxxxxxxxxx>
> > Signed-off-by: Frank Li <Frank.Li@xxxxxxx>
> > ---
> > drivers/net/can/flexcan/flexcan-core.c | 49 ++++++++++++++++++++++++++++++----
> > drivers/net/can/flexcan/flexcan.h | 2 ++
> > 2 files changed, 46 insertions(+), 5 deletions(-)
> >
> > diff --git a/drivers/net/can/flexcan/flexcan-core.c b/drivers/net/can/flexcan/flexcan-core.c
> > index f6e609c388d55..fe972d5b8fbe0 100644
> > --- a/drivers/net/can/flexcan/flexcan-core.c
> > +++ b/drivers/net/can/flexcan/flexcan-core.c
> > @@ -354,6 +354,14 @@ static struct flexcan_devtype_data fsl_imx93_devtype_data = {
> > FLEXCAN_QUIRK_SUPPORT_RX_MAILBOX_RTR,
> > };
> >
> > +static const struct flexcan_devtype_data fsl_imx95_devtype_data = {
> > + .quirks = FLEXCAN_QUIRK_DISABLE_RXFG | FLEXCAN_QUIRK_ENABLE_EACEN_RRS |
> > + FLEXCAN_QUIRK_DISABLE_MECR | FLEXCAN_QUIRK_USE_RX_MAILBOX |
> > + FLEXCAN_QUIRK_BROKEN_PERR_STATE | FLEXCAN_QUIRK_SETUP_STOP_MODE_SCMI |
> > + FLEXCAN_QUIRK_SUPPORT_FD | FLEXCAN_QUIRK_SUPPORT_ECC |
> > + FLEXCAN_QUIRK_SUPPORT_RX_MAILBOX |
> > + FLEXCAN_QUIRK_SUPPORT_RX_MAILBOX_RTR,
>
> Please keep the flags sorted by their value.
>
> > +};
>
> Please add a newline here.
>
> > static const struct flexcan_devtype_data fsl_vf610_devtype_data = {
> > .quirks = FLEXCAN_QUIRK_DISABLE_RXFG | FLEXCAN_QUIRK_ENABLE_EACEN_RRS |
> > FLEXCAN_QUIRK_DISABLE_MECR | FLEXCAN_QUIRK_USE_RX_MAILBOX |
> > @@ -548,6 +556,13 @@ static inline int flexcan_enter_stop_mode(struct flexcan_priv *priv)
> > } else if (priv->devtype_data.quirks & FLEXCAN_QUIRK_SETUP_STOP_MODE_GPR) {
> > regmap_update_bits(priv->stm.gpr, priv->stm.req_gpr,
> > 1 << priv->stm.req_bit, 1 << priv->stm.req_bit);
> > + } else if (priv->devtype_data.quirks & FLEXCAN_QUIRK_SETUP_STOP_MODE_SCMI) {
> > + /* For the SCMI mode, driver do nothing, ATF will send request to
> > + * SM(system manager, M33 core) through SCMI protocol after linux
> > + * suspend. Once SM get this request, it will send IPG_STOP signal
> > + * to Flex_CAN, let CAN in STOP mode.
> > + */
> > + return 0;
> > }
> >
> > return flexcan_low_power_enter_ack(priv);
> > @@ -559,7 +574,11 @@ static inline int flexcan_exit_stop_mode(struct flexcan_priv *priv)
> > u32 reg_mcr;
> > int ret;
> >
> > - /* remove stop request */
> > + /* Remove stop request, for FLEXCAN_QUIRK_SETUP_STOP_MODE_SCMI,
> > + * do nothing here, because ATF already send request to SM before
> > + * linux resume. Once SM get this request, it will deassert the
> > + * IPG_STOP signal to Flex_CAN.
> > + */
> > if (priv->devtype_data.quirks & FLEXCAN_QUIRK_SETUP_STOP_MODE_SCFW) {
> > ret = flexcan_stop_mode_enable_scfw(priv, false);
> > if (ret < 0)
> > @@ -1987,6 +2006,9 @@ static int flexcan_setup_stop_mode(struct platform_device *pdev)
> > ret = flexcan_setup_stop_mode_scfw(pdev);
> > else if (priv->devtype_data.quirks & FLEXCAN_QUIRK_SETUP_STOP_MODE_GPR)
> > ret = flexcan_setup_stop_mode_gpr(pdev);
> > + else if (priv->devtype_data.quirks & FLEXCAN_QUIRK_SETUP_STOP_MODE_SCMI)
> > + /* ATF will handle all STOP_IPG related work */
> > + ret = 0;
> > else
> > /* return 0 directly if doesn't support stop mode feature */
> > return 0;
> > @@ -2013,6 +2035,7 @@ static const struct of_device_id flexcan_of_match[] = {
> > { .compatible = "fsl,imx8qm-flexcan", .data = &fsl_imx8qm_devtype_data, },
> > { .compatible = "fsl,imx8mp-flexcan", .data = &fsl_imx8mp_devtype_data, },
> > { .compatible = "fsl,imx93-flexcan", .data = &fsl_imx93_devtype_data, },
> > + { .compatible = "fsl,imx95-flexcan", .data = &fsl_imx95_devtype_data, },
> > { .compatible = "fsl,imx6q-flexcan", .data = &fsl_imx6q_devtype_data, },
> > { .compatible = "fsl,imx28-flexcan", .data = &fsl_imx28_devtype_data, },
> > { .compatible = "fsl,imx53-flexcan", .data = &fsl_imx25_devtype_data, },
> > @@ -2311,9 +2334,22 @@ static int __maybe_unused flexcan_noirq_suspend(struct device *device)
> > if (netif_running(dev)) {
> > int err;
> >
> > - if (device_may_wakeup(device))
> > + if (device_may_wakeup(device)) {
> > flexcan_enable_wakeup_irq(priv, true);
> >
> > + /* For FLEXCAN_QUIRK_SETUP_STOP_MODE_SCMI, it need
> needs
> > + * ATF to send request to SM through SCMI protocol,
> > + * SM will assert the IPG_STOP signal. But all this
> > + * works need the CAN clocks keep on.
> > + * After the CAN module get the IPG_STOP mode, and
> gets
> > + * switch to STOP mode, whether still keep the CAN
> switches
> > + * clocks on or gate them off depend on the Hardware
> > + * design.
> > + */
> > + if (priv->devtype_data.quirks & FLEXCAN_QUIRK_SETUP_STOP_MODE_SCMI)
> > + return 0;
> > + }
> > +
> > err = pm_runtime_force_suspend(device);
> > if (err)
> > return err;
> > @@ -2330,9 +2366,12 @@ static int __maybe_unused flexcan_noirq_resume(struct device *device)
> > if (netif_running(dev)) {
> > int err;
> >
> > - err = pm_runtime_force_resume(device);
> > - if (err)
> > - return err;
> > + if (!(device_may_wakeup(device) &&
> ^^^^^^^^^^^^^^^^^^^^^^^^
>
> Where does this come from?

include/linux/pm_wakeup.h

static inline bool device_may_wakeup(struct device *dev)
{
return dev->power.can_wakeup && !!dev->power.wakeup;
}

Frank

>
> > + priv->devtype_data.quirks & FLEXCAN_QUIRK_SETUP_STOP_MODE_SCMI)) {
> > + err = pm_runtime_force_resume(device);
> > + if (err)
> > + return err;
> > + }
> >
> > if (device_may_wakeup(device))
> > flexcan_enable_wakeup_irq(priv, false);
> > diff --git a/drivers/net/can/flexcan/flexcan.h b/drivers/net/can/flexcan/flexcan.h
> > index 025c3417031f4..4933d8c7439e6 100644
> > --- a/drivers/net/can/flexcan/flexcan.h
> > +++ b/drivers/net/can/flexcan/flexcan.h
> > @@ -68,6 +68,8 @@
> > #define FLEXCAN_QUIRK_SUPPORT_RX_MAILBOX_RTR BIT(15)
> > /* Device supports RX via FIFO */
> > #define FLEXCAN_QUIRK_SUPPORT_RX_FIFO BIT(16)
> > +/* Setup stop mode with ATF SCMI protocol to support wakeup */
> > +#define FLEXCAN_QUIRK_SETUP_STOP_MODE_SCMI BIT(17)
> >
> > struct flexcan_devtype_data {
> > u32 quirks; /* quirks needed for different IP cores */
> >
> > --
> > 2.34.1
> >
> >
>
> regards,
> Marc
>
> --
> Pengutronix e.K. | Marc Kleine-Budde |
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