Commit 5b512f42 authored by Haibo Chen's avatar Haibo Chen Committed by Marc Kleine-Budde
Browse files

can: flexcan: add wakeup support for imx95 



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: default avatarHan Xu <han.xu@nxp.com>
Signed-off-by: default avatarHaibo Chen <haibo.chen@nxp.com>
Reviewed-by: default avatarVincent Mailhol <mailhol.vincent@wanadoo.fr>
Signed-off-by: default avatarFrank Li <Frank.Li@nxp.com>
Link: https://lore.kernel.org/all/20240731-flexcan-v4-2-82ece66e5a76@nxp.com


Signed-off-by: default avatarMarc Kleine-Budde <mkl@pengutronix.de>
parent 3eea16ba

drivers/net/can/flexcan/flexcan-core.c

+43 −7
Original line number Diff line number Diff line
@@ -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_SUPPORT_FD |

		FLEXCAN_QUIRK_SUPPORT_ECC | FLEXCAN_QUIRK_SUPPORT_RX_MAILBOX |

		FLEXCAN_QUIRK_SUPPORT_RX_MAILBOX_RTR | FLEXCAN_QUIRK_SETUP_STOP_MODE_SCMI,

};



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 |
@@ -544,6 +552,13 @@ 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);
@@ -555,7 +570,11 @@ 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)
@@ -1983,6 +2002,9 @@ 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;
@@ -2009,6 +2031,7 @@ 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, },
@@ -2309,10 +2332,20 @@ static int __maybe_unused flexcan_noirq_suspend(struct device *device) 
		if (device_may_wakeup(device))

			flexcan_enable_wakeup_irq(priv, true);



		/* For FLEXCAN_QUIRK_SETUP_STOP_MODE_SCMI, it need ATF to send

		 * 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 (!(device_may_wakeup(device) &&

		      priv->devtype_data.quirks & FLEXCAN_QUIRK_SETUP_STOP_MODE_SCMI)) {

			err = pm_runtime_force_suspend(device);

			if (err)

				return err;

		}

	}



	return 0;

}
@@ -2325,9 +2358,12 @@ static int __maybe_unused flexcan_noirq_resume(struct device *device) 
	if (netif_running(dev)) {

		int 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);

drivers/net/can/flexcan/flexcan.h

+2 −0
Original line number Diff line number Diff line
@@ -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 */