Thread (17 messages) 17 messages, 2 authors, 2023-01-03

[Patch net-next v6 05/13] net: dsa: microchip: ptp: enable interrupt for timestamping

From: Arun Ramadoss <arun.ramadoss@microchip.com>
Date: 2023-01-02 05:07:04
Also in: lkml
Subsystem: microchip ksz series ethernet switch driver, networking drivers, networking [dsa], the rest · Maintainers: Woojung Huh, Andrew Lunn, "David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Vladimir Oltean, Linus Torvalds

PTP Interrupt mask and status register differ from the global and port
interrupt mechanism by two methods. One is that for global/port
interrupt enabling we have to clear the bit but for ptp interrupt we
have to set the bit. And other is bit12:0 is reserved in ptp interrupt
registers. This forced to not use the generic implementation of
global/port interrupt method routine. This patch implement the ptp
interrupt mechanism to read the timestamp register for sync, pdelay_req
and pdelay_resp.

Signed-off-by: Arun Ramadoss <arun.ramadoss@microchip.com>
---
v4 -> v5
- Replaced the irq_domain_add_simple with  irq_domain_add_linear
- Updated the error path to free_irq

v3 -> v4
- Removed IRQF_TRIGGER_FALLING flag in the request_threaded_irq

RFC v2 -> Patch v1
- Moved the acking of interrupts before calling the handle_nested_irq to
  avoid race condition between deferred xmit and Irq threads
---
 drivers/net/dsa/microchip/ksz_common.c  |  15 +-
 drivers/net/dsa/microchip/ksz_common.h  |  11 ++
 drivers/net/dsa/microchip/ksz_ptp.c     | 207 ++++++++++++++++++++++++
 drivers/net/dsa/microchip/ksz_ptp.h     |   9 ++
 drivers/net/dsa/microchip/ksz_ptp_reg.h |  19 +++
 5 files changed, 259 insertions(+), 2 deletions(-)
diff --git a/drivers/net/dsa/microchip/ksz_common.c b/drivers/net/dsa/microchip/ksz_common.c
index 1819f75eb007..30f40619f9a3 100644
--- a/drivers/net/dsa/microchip/ksz_common.c
+++ b/drivers/net/dsa/microchip/ksz_common.c
@@ -2100,13 +2100,17 @@ static int ksz_setup(struct dsa_switch *ds)
 			ret = ksz_pirq_setup(dev, dp->index);
 			if (ret)
 				goto out_girq;
+
+			ret = ksz_ptp_irq_setup(ds, dp->index);
+			if (ret)
+				goto out_pirq;
 		}
 	}
 
 	ret = ksz_ptp_clock_register(ds);
 	if (ret) {
 		dev_err(dev->dev, "Failed to register PTP clock: %d\n", ret);
-		goto out_pirq;
+		goto out_ptpirq;
 	}
 
 	ret = ksz_mdio_register(dev);
@@ -2123,6 +2127,10 @@ static int ksz_setup(struct dsa_switch *ds)
 
 out_ptp_clock_unregister:
 	ksz_ptp_clock_unregister(ds);
+out_ptpirq:
+	if (dev->irq > 0)
+		dsa_switch_for_each_user_port(dp, dev->ds)
+			ksz_ptp_irq_free(ds, dp->index);
 out_pirq:
 	if (dev->irq > 0)
 		dsa_switch_for_each_user_port(dp, dev->ds)
@@ -2142,8 +2150,11 @@ static void ksz_teardown(struct dsa_switch *ds)
 	ksz_ptp_clock_unregister(ds);
 
 	if (dev->irq > 0) {
-		dsa_switch_for_each_user_port(dp, dev->ds)
+		dsa_switch_for_each_user_port(dp, dev->ds) {
+			ksz_ptp_irq_free(ds, dp->index);
+
 			ksz_irq_free(&dev->ports[dp->index].pirq);
+		}
 
 		ksz_irq_free(&dev->girq);
 	}
diff --git a/drivers/net/dsa/microchip/ksz_common.h b/drivers/net/dsa/microchip/ksz_common.h
index 641aca78ef05..ec1bceb4efcc 100644
--- a/drivers/net/dsa/microchip/ksz_common.h
+++ b/drivers/net/dsa/microchip/ksz_common.h
@@ -20,6 +20,7 @@
 #define KSZ_MAX_NUM_PORTS 8
 
 struct ksz_device;
+struct ksz_port;
 
 struct vlan_table {
 	u32 table[3];
@@ -83,6 +84,13 @@ struct ksz_irq {
 	struct ksz_device *dev;
 };
 
+struct ksz_ptp_irq {
+	struct ksz_port *port;
+	u16 ts_reg;
+	char name[16];
+	int num;
+};
+
 struct ksz_port {
 	bool remove_tag;		/* Remove Tag flag set, for ksz8795 only */
 	bool learning;
@@ -106,6 +114,8 @@ struct ksz_port {
 	struct hwtstamp_config tstamp_config;
 	bool hwts_tx_en;
 	bool hwts_rx_en;
+	struct ksz_irq ptpirq;
+	struct ksz_ptp_irq ptpmsg_irq[3];
 #endif
 };
 
@@ -612,6 +622,7 @@ static inline int is_lan937x(struct ksz_device *dev)
 #define REG_PORT_INT_MASK		0x001F
 
 #define PORT_SRC_PHY_INT		1
+#define PORT_SRC_PTP_INT		2
 
 #define KSZ8795_HUGE_PACKET_SIZE	2000
 #define KSZ8863_HUGE_PACKET_SIZE	1916
diff --git a/drivers/net/dsa/microchip/ksz_ptp.c b/drivers/net/dsa/microchip/ksz_ptp.c
index 16f172c1f5c2..03127b46abea 100644
--- a/drivers/net/dsa/microchip/ksz_ptp.c
+++ b/drivers/net/dsa/microchip/ksz_ptp.c
@@ -6,6 +6,8 @@
  */
 
 #include <linux/dsa/ksz_common.h>
+#include <linux/irq.h>
+#include <linux/irqdomain.h>
 #include <linux/kernel.h>
 #include <linux/ptp_classify.h>
 #include <linux/ptp_clock_kernel.h>
@@ -25,6 +27,8 @@
 #define KSZ_PTP_INC_NS 40ULL  /* HW clock is incremented every 40 ns (by 40) */
 #define KSZ_PTP_SUBNS_BITS 32
 
+#define KSZ_PTP_INT_START 13
+
 static int ksz_ptp_enable_mode(struct ksz_device *dev)
 {
 	struct ksz_tagger_data *tagger_data = ksz_tagger_data(dev->ds);
@@ -411,6 +415,209 @@ void ksz_ptp_clock_unregister(struct dsa_switch *ds)
 		ptp_clock_unregister(ptp_data->clock);
 }
 
+static irqreturn_t ksz_ptp_msg_thread_fn(int irq, void *dev_id)
+{
+	return IRQ_NONE;
+}
+
+static irqreturn_t ksz_ptp_irq_thread_fn(int irq, void *dev_id)
+{
+	struct ksz_irq *ptpirq = dev_id;
+	unsigned int nhandled = 0;
+	struct ksz_device *dev;
+	unsigned int sub_irq;
+	u16 data;
+	int ret;
+	u8 n;
+
+	dev = ptpirq->dev;
+
+	ret = ksz_read16(dev, ptpirq->reg_status, &data);
+	if (ret)
+		goto out;
+
+	/* Clear the interrupts W1C */
+	ret = ksz_write16(dev, ptpirq->reg_status, data);
+	if (ret)
+		return IRQ_NONE;
+
+	for (n = 0; n < ptpirq->nirqs; ++n) {
+		if (data & BIT(n + KSZ_PTP_INT_START)) {
+			sub_irq = irq_find_mapping(ptpirq->domain, n);
+			handle_nested_irq(sub_irq);
+			++nhandled;
+		}
+	}
+
+out:
+	return (nhandled > 0 ? IRQ_HANDLED : IRQ_NONE);
+}
+
+static void ksz_ptp_irq_mask(struct irq_data *d)
+{
+	struct ksz_irq *kirq = irq_data_get_irq_chip_data(d);
+
+	kirq->masked &= ~BIT(d->hwirq + KSZ_PTP_INT_START);
+}
+
+static void ksz_ptp_irq_unmask(struct irq_data *d)
+{
+	struct ksz_irq *kirq = irq_data_get_irq_chip_data(d);
+
+	kirq->masked |= BIT(d->hwirq + KSZ_PTP_INT_START);
+}
+
+static void ksz_ptp_irq_bus_lock(struct irq_data *d)
+{
+	struct ksz_irq *kirq  = irq_data_get_irq_chip_data(d);
+
+	mutex_lock(&kirq->dev->lock_irq);
+}
+
+static void ksz_ptp_irq_bus_sync_unlock(struct irq_data *d)
+{
+	struct ksz_irq *kirq  = irq_data_get_irq_chip_data(d);
+	struct ksz_device *dev = kirq->dev;
+	int ret;
+
+	ret = ksz_write16(dev, kirq->reg_mask, kirq->masked);
+	if (ret)
+		dev_err(dev->dev, "failed to change IRQ mask\n");
+
+	mutex_unlock(&dev->lock_irq);
+}
+
+static const struct irq_chip ksz_ptp_irq_chip = {
+	.name			= "ksz-irq",
+	.irq_mask		= ksz_ptp_irq_mask,
+	.irq_unmask		= ksz_ptp_irq_unmask,
+	.irq_bus_lock		= ksz_ptp_irq_bus_lock,
+	.irq_bus_sync_unlock	= ksz_ptp_irq_bus_sync_unlock,
+};
+
+static int ksz_ptp_irq_domain_map(struct irq_domain *d,
+				  unsigned int irq, irq_hw_number_t hwirq)
+{
+	irq_set_chip_data(irq, d->host_data);
+	irq_set_chip_and_handler(irq, &ksz_ptp_irq_chip, handle_level_irq);
+	irq_set_noprobe(irq);
+
+	return 0;
+}
+
+static const struct irq_domain_ops ksz_ptp_irq_domain_ops = {
+	.map	= ksz_ptp_irq_domain_map,
+	.xlate	= irq_domain_xlate_twocell,
+};
+
+static void ksz_ptp_msg_irq_free(struct ksz_port *port, u8 n)
+{
+	struct ksz_ptp_irq *ptpmsg_irq;
+
+	ptpmsg_irq = &port->ptpmsg_irq[n];
+
+	free_irq(ptpmsg_irq->num, ptpmsg_irq);
+	irq_dispose_mapping(ptpmsg_irq->num);
+}
+
+static int ksz_ptp_msg_irq_setup(struct ksz_port *port, u8 n)
+{
+	u16 ts_reg[] = {REG_PTP_PORT_PDRESP_TS, REG_PTP_PORT_XDELAY_TS,
+			REG_PTP_PORT_SYNC_TS};
+	static const char * const name[] = {"pdresp-msg", "xdreq-msg",
+					    "sync-msg"};
+	const struct ksz_dev_ops *ops = port->ksz_dev->dev_ops;
+	struct ksz_ptp_irq *ptpmsg_irq;
+
+	ptpmsg_irq = &port->ptpmsg_irq[n];
+
+	ptpmsg_irq->port = port;
+	ptpmsg_irq->ts_reg = ops->get_port_addr(port->num, ts_reg[n]);
+
+	snprintf(ptpmsg_irq->name, sizeof(ptpmsg_irq->name), name[n]);
+
+	ptpmsg_irq->num = irq_find_mapping(port->ptpirq.domain, n);
+	if (ptpmsg_irq->num < 0)
+		return ptpmsg_irq->num;
+
+	return request_threaded_irq(ptpmsg_irq->num, NULL,
+				    ksz_ptp_msg_thread_fn, IRQF_ONESHOT,
+				    ptpmsg_irq->name, ptpmsg_irq);
+}
+
+int ksz_ptp_irq_setup(struct dsa_switch *ds, u8 p)
+{
+	struct ksz_device *dev = ds->priv;
+	const struct ksz_dev_ops *ops = dev->dev_ops;
+	struct ksz_port *port = &dev->ports[p];
+	struct ksz_irq *ptpirq = &port->ptpirq;
+	int irq;
+	int ret;
+
+	ptpirq->dev = dev;
+	ptpirq->masked = 0;
+	ptpirq->nirqs = 3;
+	ptpirq->reg_mask = ops->get_port_addr(p, REG_PTP_PORT_TX_INT_ENABLE__2);
+	ptpirq->reg_status = ops->get_port_addr(p,
+						REG_PTP_PORT_TX_INT_STATUS__2);
+	snprintf(ptpirq->name, sizeof(ptpirq->name), "ptp-irq-%d", p);
+
+	ptpirq->domain = irq_domain_add_linear(dev->dev->of_node, ptpirq->nirqs,
+					       &ksz_ptp_irq_domain_ops, ptpirq);
+	if (!ptpirq->domain)
+		return -ENOMEM;
+
+	for (irq = 0; irq < ptpirq->nirqs; irq++)
+		irq_create_mapping(ptpirq->domain, irq);
+
+	ptpirq->irq_num = irq_find_mapping(port->pirq.domain, PORT_SRC_PTP_INT);
+	if (ptpirq->irq_num < 0) {
+		ret = ptpirq->irq_num;
+		goto out;
+	}
+
+	ret = request_threaded_irq(ptpirq->irq_num, NULL, ksz_ptp_irq_thread_fn,
+				   IRQF_ONESHOT, ptpirq->name, ptpirq);
+	if (ret)
+		goto out;
+
+	for (irq = 0; irq < ptpirq->nirqs; irq++) {
+		ret = ksz_ptp_msg_irq_setup(port, irq);
+		if (ret)
+			goto out_ptp_msg;
+	}
+
+	return 0;
+
+out_ptp_msg:
+	free_irq(ptpirq->irq_num, ptpirq);
+	while (irq--)
+		free_irq(port->ptpmsg_irq[irq].num, &port->ptpmsg_irq[irq]);
+out:
+	for (irq = 0; irq < ptpirq->nirqs; irq++)
+		irq_dispose_mapping(port->ptpmsg_irq[irq].num);
+
+	irq_domain_remove(ptpirq->domain);
+
+	return ret;
+}
+
+void ksz_ptp_irq_free(struct dsa_switch *ds, u8 p)
+{
+	struct ksz_device *dev = ds->priv;
+	struct ksz_port *port = &dev->ports[p];
+	struct ksz_irq *ptpirq = &port->ptpirq;
+	u8 n;
+
+	for (n = 0; n < ptpirq->nirqs; n++)
+		ksz_ptp_msg_irq_free(port, n);
+
+	free_irq(ptpirq->irq_num, ptpirq);
+	irq_dispose_mapping(ptpirq->irq_num);
+
+	irq_domain_remove(ptpirq->domain);
+}
+
 MODULE_AUTHOR("Christian Eggers <ceggers@arri.de>");
 MODULE_AUTHOR("Arun Ramadoss <arun.ramadoss@microchip.com>");
 MODULE_DESCRIPTION("PTP support for KSZ switch");
diff --git a/drivers/net/dsa/microchip/ksz_ptp.h b/drivers/net/dsa/microchip/ksz_ptp.h
index 2c29a0b604bb..7c5679372705 100644
--- a/drivers/net/dsa/microchip/ksz_ptp.h
+++ b/drivers/net/dsa/microchip/ksz_ptp.h
@@ -30,6 +30,8 @@ int ksz_get_ts_info(struct dsa_switch *ds, int port,
 		    struct ethtool_ts_info *ts);
 int ksz_hwtstamp_get(struct dsa_switch *ds, int port, struct ifreq *ifr);
 int ksz_hwtstamp_set(struct dsa_switch *ds, int port, struct ifreq *ifr);
+int ksz_ptp_irq_setup(struct dsa_switch *ds, u8 p);
+void ksz_ptp_irq_free(struct dsa_switch *ds, u8 p);
 
 #else
 
@@ -45,6 +47,13 @@ static inline int ksz_ptp_clock_register(struct dsa_switch *ds)
 
 static inline void ksz_ptp_clock_unregister(struct dsa_switch *ds) { }
 
+static inline int ksz_ptp_irq_setup(struct dsa_switch *ds, u8 p)
+{
+	return 0;
+}
+
+static inline void ksz_ptp_irq_free(struct dsa_switch *ds, u8 p) {}
+
 #define ksz_get_ts_info NULL
 
 #define ksz_hwtstamp_get NULL
diff --git a/drivers/net/dsa/microchip/ksz_ptp_reg.h b/drivers/net/dsa/microchip/ksz_ptp_reg.h
index 4ca4ad4bba7e..abe95bbefc12 100644
--- a/drivers/net/dsa/microchip/ksz_ptp_reg.h
+++ b/drivers/net/dsa/microchip/ksz_ptp_reg.h
@@ -49,4 +49,23 @@
 #define PTP_MASTER			BIT(1)
 #define PTP_1STEP			BIT(0)
 
+/* Port PTP Register */
+#define REG_PTP_PORT_RX_DELAY__2	0x0C00
+#define REG_PTP_PORT_TX_DELAY__2	0x0C02
+#define REG_PTP_PORT_ASYM_DELAY__2	0x0C04
+
+#define REG_PTP_PORT_XDELAY_TS		0x0C08
+#define REG_PTP_PORT_SYNC_TS		0x0C0C
+#define REG_PTP_PORT_PDRESP_TS		0x0C10
+
+#define REG_PTP_PORT_TX_INT_STATUS__2	0x0C14
+#define REG_PTP_PORT_TX_INT_ENABLE__2	0x0C16
+
+#define PTP_PORT_SYNC_INT		BIT(15)
+#define PTP_PORT_XDELAY_REQ_INT		BIT(14)
+#define PTP_PORT_PDELAY_RESP_INT	BIT(13)
+#define KSZ_SYNC_MSG			2
+#define KSZ_XDREQ_MSG			1
+#define KSZ_PDRES_MSG			0
+
 #endif
-- 
2.36.1
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