[PATCH net-next v2 10/10] net: ethernet: ravb: Add gPTP support for Gen4

["Niklas Söderlund" <niklas.soderlund+renesas@ragnatech.se>]

While driver advertises 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 ptp-timer property is optional.If 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@ragnatech.se>
Reviewed-by: Sergey Shtylyov <sergei.shtylyov@gmail.com>
---
* Changes since v1
- Use the standard generic ptp-timer property from
  ethernet-controller.yaml instead of a vendor specific one.
- Improve spelling in commit message.
---
 drivers/net/ethernet/renesas/ravb.h      |  3 ++
 drivers/net/ethernet/renesas/ravb_main.c | 56 +++++++++++++++++++++++-
 2 files changed, 58 insertions(+), 1 deletion(-)

diff --git a/drivers/net/ethernet/renesas/ravb.h b/drivers/net/ethernet/renesas/ravb.h
index b4df5cab0e5c..4c8dc02022e2 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 12877a8488ed..30170e92d3d7 100644
--- a/drivers/net/ethernet/renesas/ravb_main.c
+++ b/drivers/net/ethernet/renesas/ravb_main.c
@@ -2752,6 +2752,59 @@ 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, "ptp-timer", 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,
@@ -2774,7 +2827,7 @@ 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,
 };
@@ -3186,6 +3239,7 @@ 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);
-- 
2.55.0