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

Vincent MAILHOL
2024-07-12T02:36:58Z

Hi,

Thank you for the patch. I am not familiar with the iMX95 quirks, but
to the extent of my knowledge, the patch looks good.

Here are a few nits. Next time, maybe you should run a syntax checker
to catch the easy mistakes in the English grammar.

You can directly add my review tag to the v2:

Reviewed-by: Vincent Mailhol <mailhol.vincent@wanadoo.fr>

Le ven. 12 juil. 2024 à 03:24, Frank Li <Frank.Li@nxp.com> a écrit :
>
> From: Haibo Chen <haibo.chen@nxp.com>
>
> iMX95 define a bit in GPR that assert/desert IPG_STOP signal to Flex CAN
^^^^^^
define -> defines
assert/desert -> desert means to "run away" or "leave behind". Not
sure this is the correct word here. Maybe something like set/unset is
better here? This sentence is worth rephrasing.

> module. It control flexcan enter STOP mode. Wakeup should work even FlexCAN
^^^^^^^ ^^^^
control -> controls
even -> even if

> is in STOP mode.
>
> Due to iMX95 architecture design, A-Core can't access GPR. Only the system
> manager (SM) can config GPR. To support the wakeup feature, follow below
^^^^^^
config -> configure
>
> For suspend:
>
> 1) linux suspend, when CAN suspend, do nothing for GPR, and keep CAN
> related clock on.
> 2) In ATF, check whether the CAN need to support wakeup, if yes, send a
^^^^
need -> needs

> request to SM through SCMI protocol.
> 3) In SM, config the GPR and assert IPG_STOP.
> 4) A-Core suspend.
>
> For wakeup and resume:
>
> 1) A-core wakeup event arrive.
> 2) In SM, deassert IPG_STOP.
> 3) Linux resume.

Indent your lists:

- For suspend:

1) linux suspend, when CAN suspend, do nothing for GPR, and keep CAN
related clock on.
2) In ATF, check whether the CAN need to support wakeup, if yes, send a
request to SM through SCMI protocol.
3) In SM, config the GPR and assert IPG_STOP.
4) A-Core suspend.

- For wakeup and resume:

1) A-core wakeup event arrive.
2) In SM, deassert IPG_STOP.
3) Linux resume.

> Add a new fsl_imx95_devtype_data and FLEXCAN_QUIRK_SETUP_STOP_MODE_SCMI to
> reflect this.
>
> Reviewed-by: Han Xu <han.xu@nxp.com>
> Signed-off-by: Haibo Chen <haibo.chen@nxp.com>
> Signed-off-by: Frank Li <Frank.Li@nxp.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..ad3240e7e6ab4 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 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,
> +};

Can you declare this as constant?

static const struct flexcan_devtype_data fsl_imx95_devtype_data = {

> 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
> + * 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
> + * switch to STOP mode, whether still keep the CAN
> + * 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) &&
> + 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
>
>