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[RFC,net-next,3/6] net: dsa: microchip: Manipulating absolute time using ptp hw clock

Message ID 20221014152857.32645-4-arun.ramadoss@microchip.com (mailing list archive)
State RFC
Delegated to: Netdev Maintainers
Headers show
Series net: dsa: microchip: add gPTP support for LAN937x switch | expand

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netdev/patch_count success Link
netdev/header_inline success No static functions without inline keyword in header files
netdev/build_32bit fail Errors and warnings before: 8 this patch: 8
netdev/cc_maintainers success CCed 11 of 11 maintainers
netdev/build_clang fail Errors and warnings before: 8 this patch: 8
netdev/module_param success Was 0 now: 0
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netdev/verify_fixes success No Fixes tag
netdev/build_allmodconfig_warn fail Errors and warnings before: 8 this patch: 8
netdev/checkpatch success total: 0 errors, 0 warnings, 0 checks, 119 lines checked
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Commit Message

Arun Ramadoss Oct. 14, 2022, 3:28 p.m. UTC
This patch is used for reconstructing the absolute time from the 32bit
hardware time stamping value. The do_aux ioctl is used for reading the
ptp hardware clock and store it to global variable.
The timestamped value in tail tag during rx and register during tx are
32 bit value (2 bit seconds and 30 bit nanoseconds). The time taken to
read entire ptp clock will be time consuming. In order to speed up, the
software clock is maintained. This clock time will be added to 32 bit
timestamp to get the absolute time stamp.

Signed-off-by: Arun Ramadoss <arun.ramadoss@microchip.com>
---
 drivers/net/dsa/microchip/ksz_common.h |  1 +
 drivers/net/dsa/microchip/ksz_ptp.c    | 55 +++++++++++++++++++++++++-
 drivers/net/dsa/microchip/ksz_ptp.h    |  3 ++
 3 files changed, 57 insertions(+), 2 deletions(-)
diff mbox series

Patch

diff --git a/drivers/net/dsa/microchip/ksz_common.h b/drivers/net/dsa/microchip/ksz_common.h
index 0e5f02d3992e..b15bcb6251e9 100644
--- a/drivers/net/dsa/microchip/ksz_common.h
+++ b/drivers/net/dsa/microchip/ksz_common.h
@@ -7,6 +7,7 @@ 
 #ifndef __KSZ_COMMON_H
 #define __KSZ_COMMON_H
 
+#include <linux/dsa/ksz_common.h>
 #include <linux/etherdevice.h>
 #include <linux/kernel.h>
 #include <linux/mutex.h>
diff --git a/drivers/net/dsa/microchip/ksz_ptp.c b/drivers/net/dsa/microchip/ksz_ptp.c
index 5199840377aa..c4cef3884a4d 100644
--- a/drivers/net/dsa/microchip/ksz_ptp.c
+++ b/drivers/net/dsa/microchip/ksz_ptp.c
@@ -24,12 +24,22 @@ 
 
 static int ksz_ptp_enable_mode(struct ksz_device *dev, bool enable)
 {
+	struct ksz_ptp_data *ptp_data = &dev->ptp_data;
 	u16 data = 0;
+	int ret;
 
 	/* Enable PTP mode */
-	if (enable)
+	if (enable) {
 		data = PTP_ENABLE;
 
+		/* Schedule cyclic call of ksz_ptp_do_aux_work() */
+		ret = ptp_schedule_worker(ptp_data->clock, 0);
+		if (ret)
+			return ret;
+	} else {
+		ptp_cancel_worker_sync(ptp_data->clock);
+	}
+
 	return ksz_rmw16(dev, REG_PTP_MSG_CONF1, PTP_ENABLE, data);
 }
 
@@ -223,6 +233,10 @@  static int ksz_ptp_settime(struct ptp_clock_info *ptp,
 	/* Load PTP clock from shadow registers */
 	ret = ksz_rmw16(dev, REG_PTP_CLK_CTRL, PTP_LOAD_TIME, PTP_LOAD_TIME);
 
+	spin_lock_bh(&ptp_data->clock_lock);
+	ptp_data->clock_time = *ts;
+	spin_unlock_bh(&ptp_data->clock_lock);
+
 error_return:
 	mutex_unlock(&ptp_data->lock);
 
@@ -276,6 +290,7 @@  static int ksz_ptp_adjtime(struct ptp_clock_info *ptp, s64 delta)
 {
 	struct ksz_ptp_data *ptp_data = ptp_caps_to_data(ptp);
 	struct ksz_device *dev = ptp_data_to_ksz_dev(ptp_data);
+	struct timespec64 delta64 = ns_to_timespec64(delta);
 	s32 sec, nsec;
 	u16 data16;
 	int ret;
@@ -309,14 +324,48 @@  static int ksz_ptp_adjtime(struct ptp_clock_info *ptp, s64 delta)
 
 	ret = ksz_write16(dev, REG_PTP_CLK_CTRL, data16);
 
+	spin_lock_bh(&ptp_data->clock_lock);
+	ptp_data->clock_time = timespec64_add(ptp_data->clock_time, delta64);
+	spin_unlock_bh(&ptp_data->clock_lock);
+
 error_return:
 	mutex_unlock(&ptp_data->lock);
 	return ret;
 }
 
+/*  Function is pointer to the do_aux_work in the ptp_clock capability */
+static long ksz_ptp_do_aux_work(struct ptp_clock_info *ptp)
+{
+	struct ksz_ptp_data *ptp_data = ptp_caps_to_data(ptp);
+	struct ksz_device *dev = ptp_data_to_ksz_dev(ptp_data);
+	struct timespec64 ts;
+
+	mutex_lock(&ptp_data->lock);
+	_ksz_ptp_gettime(dev, &ts);
+	mutex_unlock(&ptp_data->lock);
+
+	spin_lock_bh(&ptp_data->clock_lock);
+	ptp_data->clock_time = ts;
+	spin_unlock_bh(&ptp_data->clock_lock);
+
+	return HZ;  /* reschedule in 1 second */
+}
+
 static int ksz_ptp_start_clock(struct ksz_device *dev)
 {
-	return ksz_rmw16(dev, REG_PTP_CLK_CTRL, PTP_CLK_ENABLE, PTP_CLK_ENABLE);
+	struct ksz_ptp_data *ptp_data = &dev->ptp_data;
+	int ret;
+
+	ret = ksz_rmw16(dev, REG_PTP_CLK_CTRL, PTP_CLK_ENABLE, PTP_CLK_ENABLE);
+	if (ret)
+		return ret;
+
+	spin_lock_bh(&ptp_data->clock_lock);
+	ptp_data->clock_time.tv_sec = 0;
+	ptp_data->clock_time.tv_nsec = 0;
+	spin_unlock_bh(&ptp_data->clock_lock);
+
+	return 0;
 }
 
 static const struct ptp_clock_info ksz_ptp_caps = {
@@ -327,6 +376,7 @@  static const struct ptp_clock_info ksz_ptp_caps = {
 	.settime64	= ksz_ptp_settime,
 	.adjfine	= ksz_ptp_adjfine,
 	.adjtime	= ksz_ptp_adjtime,
+	.do_aux_work	= ksz_ptp_do_aux_work,
 };
 
 int ksz_ptp_clock_register(struct dsa_switch *ds)
@@ -336,6 +386,7 @@  int ksz_ptp_clock_register(struct dsa_switch *ds)
 	int ret;
 
 	mutex_init(&ptp_data->lock);
+	spin_lock_init(&ptp_data->clock_lock);
 
 	ptp_data->caps = ksz_ptp_caps;
 
diff --git a/drivers/net/dsa/microchip/ksz_ptp.h b/drivers/net/dsa/microchip/ksz_ptp.h
index 4c024cc9d935..09c0e58c365e 100644
--- a/drivers/net/dsa/microchip/ksz_ptp.h
+++ b/drivers/net/dsa/microchip/ksz_ptp.h
@@ -13,6 +13,9 @@  struct ksz_ptp_data {
 	struct ptp_clock *clock;
 	/* Serializes all operations on the PTP hardware clock */
 	struct mutex lock;
+	/* lock for accessing the clock_time */
+	spinlock_t clock_lock;
+	struct timespec64 clock_time;
 };
 
 int ksz_ptp_clock_register(struct dsa_switch *ds);