can: rcar_canfd: Add suspend/resume support

On R-Car Gen3 using PSCI, s2ram powers down the SoC.  After resume, the
CAN-FD interface no longer works.  Trying to bring it up again fails:

    # ip link set can0 up
    RTNETLINK answers: Connection timed out

    # dmesg
    ...
    channel 0 communication state failed

Fix this by populating the (currently empty) suspend and resume
callbacks, to stop/start the individual CAN-FD channels, and
(de)initialize the CAN-FD controller.

Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Tested-by: Biju Das <biju.das.jz@bp.renesas.com>
Signed-off-by: Biju Das <biju.das.jz@bp.renesas.com>
Link: https://patch.msgid.link/20251124102837.106973-8-biju.das.jz@bp.renesas.com
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>

1 files changed, 53 insertions, 0 deletions

diff --git a/drivers/net/can/rcar/rcar_canfd.c b/drivers/net/can/rcar/rcar_canfd.c
index 1d6b2f7efa8c..ce75948e6af6 100644
--- a/drivers/net/can/rcar/rcar_canfd.c
+++ b/drivers/net/can/rcar/rcar_canfd.c
@@ -2257,11 +2257,64 @@ static void rcar_canfd_remove(struct platform_device *pdev)
 
 static int rcar_canfd_suspend(struct device *dev)
 {
+	struct rcar_canfd_global *gpriv = dev_get_drvdata(dev);
+	int err;
+	u32 ch;
+
+	for_each_set_bit(ch, &gpriv->channels_mask, gpriv->info->max_channels) {
+		struct rcar_canfd_channel *priv = gpriv->ch[ch];
+		struct net_device *ndev = priv->ndev;
+
+		if (!netif_running(ndev))
+			continue;
+
+		netif_device_detach(ndev);
+
+		err = rcar_canfd_close(ndev);
+		if (err) {
+			netdev_err(ndev, "rcar_canfd_close() failed %pe\n",
+				   ERR_PTR(err));
+			return err;
+		}
+
+		priv->can.state = CAN_STATE_SLEEPING;
+	}
+
+	/* TODO Skip if wake-up (which is not yet supported) is enabled */
+	rcar_canfd_global_deinit(gpriv, false);
+
 	return 0;
 }
 
 static int rcar_canfd_resume(struct device *dev)
 {
+	struct rcar_canfd_global *gpriv = dev_get_drvdata(dev);
+	int err;
+	u32 ch;
+
+	err = rcar_canfd_global_init(gpriv);
+	if (err) {
+		dev_err(dev, "rcar_canfd_global_init() failed %pe\n", ERR_PTR(err));
+		return err;
+	}
+
+	for_each_set_bit(ch, &gpriv->channels_mask, gpriv->info->max_channels) {
+		struct rcar_canfd_channel *priv = gpriv->ch[ch];
+		struct net_device *ndev = priv->ndev;
+
+		if (!netif_running(ndev))
+			continue;
+
+		err = rcar_canfd_open(ndev);
+		if (err) {
+			netdev_err(ndev, "rcar_canfd_open() failed %pe\n",
+				   ERR_PTR(err));
+			return err;
+		}
+
+		netif_device_attach(ndev);
+	}
+
 	return 0;
 }