diff mbox series

[net,v4] net: ti: icssg-prueth: Fix 1 PPS sync

Message ID 20241106072314.3361048-1-m-malladi@ti.com (mailing list archive)
State New
Delegated to: Netdev Maintainers
Headers show
Series [net,v4] net: ti: icssg-prueth: Fix 1 PPS sync | expand

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Context Check Description
netdev/series_format success Single patches do not need cover letters
netdev/tree_selection success Clearly marked for net
netdev/ynl success Generated files up to date; no warnings/errors; no diff in generated;
netdev/fixes_present success Fixes tag present in non-next series
netdev/header_inline success No static functions without inline keyword in header files
netdev/build_32bit success Errors and warnings before: 3 this patch: 3
netdev/build_tools success No tools touched, skip
netdev/cc_maintainers success CCed 10 of 10 maintainers
netdev/build_clang success Errors and warnings before: 3 this patch: 3
netdev/verify_signedoff success Signed-off-by tag matches author and committer
netdev/deprecated_api success None detected
netdev/check_selftest success No net selftest shell script
netdev/verify_fixes success Fixes tag looks correct
netdev/build_allmodconfig_warn success Errors and warnings before: 3 this patch: 3
netdev/checkpatch success total: 0 errors, 0 warnings, 0 checks, 49 lines checked
netdev/build_clang_rust success No Rust files in patch. Skipping build
netdev/kdoc success Errors and warnings before: 0 this patch: 0
netdev/source_inline success Was 0 now: 0
netdev/contest pending net-next-2024-11-06--09-00 (tests: 0)

Commit Message

Meghana Malladi Nov. 6, 2024, 7:23 a.m. UTC
The first PPS latch time needs to be calculated by the driver
(in rounded off seconds) and configured as the start time
offset for the cycle. After synchronizing two PTP clocks
running as master/slave, missing this would cause master
and slave to start immediately with some milliseconds
drift which causes the PPS signal to never synchronize with
the PTP master.

Fixes: 186734c15886 ("net: ti: icssg-prueth: add packet timestamping and ptp support")
Signed-off-by: Meghana Malladi <m-malladi@ti.com>
---

This patch is based on net-next tagged next-2024102.
v3:https://lore.kernel.org/all/20241028111051.1546143-1-m-malladi@ti.com
* Changes since v3 (v4-v3):
- Update read function to handle hi/lo race between reads as 
suggested by Jakub Kicinski <kuba@kernel.org>

* Changes since v2 (v3-v2):
- Use hi_lo_writeq() and hi_lo_readq() instead of own helpers
(icssg_readq() & iccsg_writeq()) as asked by Andrew Lunn <andrew@lunn.ch>
- Collected Reviewed-by tags from Vadim and Danish

* Changes since v1 (v2-v1):
- Use roundup() instead of open coding as suggested by Vadim Fedorenko

 drivers/net/ethernet/ti/icssg/icssg_prueth.c | 13 +++++++++++--
 drivers/net/ethernet/ti/icssg/icssg_prueth.h | 12 ++++++++++++
 2 files changed, 23 insertions(+), 2 deletions(-)


base-commit: 73840ca5ef361f143b89edd5368a1aa8c2979241
diff mbox series

Patch

diff --git a/drivers/net/ethernet/ti/icssg/icssg_prueth.c b/drivers/net/ethernet/ti/icssg/icssg_prueth.c
index 0556910938fa..cae8a4f450bb 100644
--- a/drivers/net/ethernet/ti/icssg/icssg_prueth.c
+++ b/drivers/net/ethernet/ti/icssg/icssg_prueth.c
@@ -16,6 +16,7 @@ 
 #include <linux/if_hsr.h>
 #include <linux/if_vlan.h>
 #include <linux/interrupt.h>
+#include <linux/io-64-nonatomic-hi-lo.h>
 #include <linux/kernel.h>
 #include <linux/mfd/syscon.h>
 #include <linux/module.h>
@@ -411,6 +412,8 @@  static int prueth_perout_enable(void *clockops_data,
 	struct prueth_emac *emac = clockops_data;
 	u32 reduction_factor = 0, offset = 0;
 	struct timespec64 ts;
+	u64 current_cycle;
+	u64 start_offset;
 	u64 ns_period;
 
 	if (!on)
@@ -449,8 +452,14 @@  static int prueth_perout_enable(void *clockops_data,
 	writel(reduction_factor, emac->prueth->shram.va +
 		TIMESYNC_FW_WC_SYNCOUT_REDUCTION_FACTOR_OFFSET);
 
-	writel(0, emac->prueth->shram.va +
-		TIMESYNC_FW_WC_SYNCOUT_START_TIME_CYCLECOUNT_OFFSET);
+	current_cycle = icssg_readq(emac->prueth->shram.va +
+				    TIMESYNC_FW_WC_CYCLECOUNT_OFFSET);
+
+	/* Rounding of current_cycle count to next second */
+	start_offset = roundup(current_cycle, MSEC_PER_SEC);
+
+	hi_lo_writeq(start_offset, emac->prueth->shram.va +
+		     TIMESYNC_FW_WC_SYNCOUT_START_TIME_CYCLECOUNT_OFFSET);
 
 	return 0;
 }
diff --git a/drivers/net/ethernet/ti/icssg/icssg_prueth.h b/drivers/net/ethernet/ti/icssg/icssg_prueth.h
index 8722bb4a268a..5c194c6991bf 100644
--- a/drivers/net/ethernet/ti/icssg/icssg_prueth.h
+++ b/drivers/net/ethernet/ti/icssg/icssg_prueth.h
@@ -330,6 +330,18 @@  static inline int prueth_emac_slice(struct prueth_emac *emac)
 extern const struct ethtool_ops icssg_ethtool_ops;
 extern const struct dev_pm_ops prueth_dev_pm_ops;
 
+static inline __u64 icssg_readq(const void __iomem *addr)
+{
+	u32 low, high;
+
+	do {
+		high = readl(addr + 4);
+		low = readl(addr);
+	} while (high != readl(addr + 4));
+
+	return low + ((u64)high << 32);
+}
+
 /* Classifier helpers */
 void icssg_class_set_mac_addr(struct regmap *miig_rt, int slice, u8 *mac);
 void icssg_class_set_host_mac_addr(struct regmap *miig_rt, const u8 *mac);