[net-next 9/9] net: ethernet: ravb: Add gPTP support for Gen4

[Niklas Söderlund]

While driver advertise gPTP support on Gen4 platforms it is in fact
completely broken. On R-Car Gen4 devices the RAVB module have no
internal gPTP clock as generations before it. Instead it utilizes a
system wide gPTP clock.

This change utilizes the refactoring of the RAVB gPTP code to add
support for a system wide clock and stops the Gen4 devices trying to use
the non-existing internal gPTP clock.

To remain backward compatible the device tree property needed
(renesas,gptp) to get hold of the system gPTP clock is optional. If the
property is not present, or not enabled, the RAVB driver will no longer
advertise gPTP support to user-space.

Signed-off-by: Niklas Söderlund <niklas.soderlund+renesas@xxxxxxxxxxxx>
---
 drivers/net/ethernet/renesas/ravb.h      |  3 ++
 drivers/net/ethernet/renesas/ravb_main.c | 55 +++++++++++++++++++++++-
 2 files changed, 57 insertions(+), 1 deletion(-)

diff --git a/drivers/net/ethernet/renesas/ravb.h b/drivers/net/ethernet/renesas/ravb.h
index caad95a9c3c5..acdfb56bb135 100644
--- a/drivers/net/ethernet/renesas/ravb.h
+++ b/drivers/net/ethernet/renesas/ravb.h
@@ -249,6 +249,8 @@ enum APSR_BIT {
 	APSR_RDM	= 0x00002000,
 	APSR_TDM	= 0x00004000,
 	APSR_MIISELECT	= 0x01000000,	/* R-Car V4M only */
+	APSR_GPTPTIMER_SOURCE = BIT(25), /* Gen4 */
+	APSR_GPTPCLOCK	= BIT(29),	/* Gen4 */
 };
 
 /* RCR */
@@ -1132,6 +1134,7 @@ struct ravb_private {
 	struct list_head ts_skb_list;
 	u32 ts_skb_tag;
 	struct ravb_ptp ptp;
+	struct device_node *of_gptp;	/* Reference to external gPTP clock, if any. */
 	spinlock_t lock;		/* Register access lock */
 	u32 cur_rx[NUM_RX_QUEUE];	/* Consumer ring indices */
 	u32 dirty_rx[NUM_RX_QUEUE];	/* Producer ring indices */
diff --git a/drivers/net/ethernet/renesas/ravb_main.c b/drivers/net/ethernet/renesas/ravb_main.c
index 4b0d06fb5f4c..985b2cb93617 100644
--- a/drivers/net/ethernet/renesas/ravb_main.c
+++ b/drivers/net/ethernet/renesas/ravb_main.c
@@ -2749,6 +2749,58 @@ static const struct ravb_hw_info ravb_gen3_hw_info = {
 	.magic_pkt = 1,
 };
 
+static int ravb_gen4_ptp_probe(struct net_device *ndev)
+{
+	struct ravb_private *priv = netdev_priv(ndev);
+
+	priv->of_gptp = of_parse_phandle(priv->pdev->dev.of_node, "renesas,gptp", 0);
+	if (!priv->of_gptp)
+		return 0;
+
+	if (!of_device_is_available(priv->of_gptp)) {
+		of_node_put(priv->of_gptp);
+		priv->of_gptp = NULL;
+		return 0;
+	}
+
+	return 0;
+}
+
+static int ravb_gen4_ptp_clock_index(struct net_device *ndev)
+{
+	struct ravb_private *priv = netdev_priv(ndev);
+
+	/* If no clock, mimic ptp_clock_index_by_of_node() fail and return -1 */
+	if (!priv->of_gptp)
+		return -1;
+
+	return ptp_clock_index_by_of_node(priv->of_gptp);
+}
+
+static int ravb_gen4_ptp_set_config_mode(struct net_device *ndev)
+{
+	struct ravb_private *priv = netdev_priv(ndev);
+	int ret;
+
+	/* Enable gPTP Clock and Select High-speed peripheral bus clock. */
+	ret = ravb_set_opmode(ndev, CCC_OPC_CONFIG | CCC_GAC | CCC_CSEL_HPB);
+	if (ret)
+		return ret;
+
+	/* Set PTP source to GPTP module, only option on Gen4. */
+	if (priv->of_gptp)
+		ravb_modify(ndev, APSR, APSR_GPTPTIMER_SOURCE | APSR_GPTPCLOCK,
+			    APSR_GPTPTIMER_SOURCE | APSR_GPTPCLOCK);
+
+	return 0;
+}
+
+static const struct ravb_gptp_info ravb_gen4_ptp_info = {
+	.probe = ravb_gen4_ptp_probe,
+	.clock_index = ravb_gen4_ptp_clock_index,
+	.set_config_mode = ravb_gen4_ptp_set_config_mode,
+};
+
 static const struct ravb_hw_info ravb_gen4_hw_info = {
 	.receive = ravb_rx_rcar,
 	.set_rate = ravb_set_rate_rcar,
@@ -2771,7 +2823,7 @@ static const struct ravb_hw_info ravb_gen4_hw_info = {
 	.tx_counters = 1,
 	.multi_irqs = 1,
 	.irq_en_dis = 1,
-	.ptp = &ravb_gen3_ptp_info,
+	.ptp = &ravb_gen4_ptp_info,
 	.nc_queues = 1,
 	.magic_pkt = 1,
 };
@@ -3183,6 +3235,7 @@ static void ravb_remove(struct platform_device *pdev)
 	pm_runtime_disable(&pdev->dev);
 	pm_runtime_dont_use_autosuspend(dev);
 	clk_unprepare(priv->refclk);
+	of_node_put(priv->of_gptp);
 	reset_control_assert(priv->rstc);
 	free_netdev(ndev);
 	platform_set_drvdata(pdev, NULL);
-- 
2.54.0