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Message-ID: <20240716-curious-scorpion-of-glory-8265aa-mkl@pengutronix.de>
Date: Tue, 16 Jul 2024 09:06:14 +0200
From: Marc Kleine-Budde <mkl@...gutronix.de>
To: Frank Li <Frank.Li@....com>
Cc: Vincent Mailhol <mailhol.vincent@...adoo.fr>,
"David S. Miller" <davem@...emloft.net>, Eric Dumazet <edumazet@...gle.com>,
Jakub Kicinski <kuba@...nel.org>, Paolo Abeni <pabeni@...hat.com>, Rob Herring <robh@...nel.org>,
Krzysztof Kozlowski <krzk+dt@...nel.org>, Conor Dooley <conor+dt@...nel.org>, linux-can@...r.kernel.org,
netdev@...r.kernel.org, devicetree@...r.kernel.org, linux-kernel@...r.kernel.org,
haibo.chen@....com, imx@...ts.linux.dev, han.xu@....com
Subject: Re: [PATCH v2 4/4] can: flexcan: add wakeup support for imx95
On 15.07.2024 17:27:23, Frank Li wrote:
> From: Haibo Chen <haibo.chen@....com>
>
> 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@....com>
> Signed-off-by: Haibo Chen <haibo.chen@....com>
> Reviewed-by: Vincent Mailhol <mailhol.vincent@...adoo.fr>
> Signed-off-by: Frank Li <Frank.Li@....com>
> ---
> 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?
> + 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 |
Embedded Linux | https://www.pengutronix.de |
Vertretung Nürnberg | Phone: +49-5121-206917-129 |
Amtsgericht Hildesheim, HRA 2686 | Fax: +49-5121-206917-9 |
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