[PATCH net-next v2 07/11] net: dsa: microchip: ksz9477: add Posix clock support for chip PTP clock

Christian Eggers
2020-11-12T15:47:39Z

Implement routines (adjfine, adjtime, gettime and settime) for
manipulating the chip's PTP clock.

Signed-off-by: Christian Eggers <ceggers@arri.de>
---
drivers/net/dsa/microchip/Kconfig | 9 +
drivers/net/dsa/microchip/Makefile | 1 +
drivers/net/dsa/microchip/ksz9477_i2c.c | 2 +-
drivers/net/dsa/microchip/ksz9477_main.c | 17 ++
drivers/net/dsa/microchip/ksz9477_ptp.c | 301 +++++++++++++++++++++++
drivers/net/dsa/microchip/ksz9477_ptp.h | 27 ++
drivers/net/dsa/microchip/ksz9477_spi.c | 2 +-
drivers/net/dsa/microchip/ksz_common.h | 1 +
include/linux/dsa/ksz_common.h | 7 +
9 files changed, 365 insertions(+), 2 deletions(-)
create mode 100644 drivers/net/dsa/microchip/ksz9477_ptp.c
create mode 100644 drivers/net/dsa/microchip/ksz9477_ptp.h

diff --git a/drivers/net/dsa/microchip/Kconfig b/drivers/net/dsa/microchip/Kconfig
index 4ec6a47b7f72..71cc910e5941 100644
--- a/drivers/net/dsa/microchip/Kconfig
+++ b/drivers/net/dsa/microchip/Kconfig
@@ -24,6 +24,15 @@ config NET_DSA_MICROCHIP_KSZ9477_SPI
help
Select to enable support for registering switches configured through SPI.

+config NET_DSA_MICROCHIP_KSZ9477_PTP
+ bool "PTP support for Microchip KSZ9477 series"
+ default n
+ depends on NET_DSA_MICROCHIP_KSZ9477
+ depends on PTP_1588_CLOCK
+ help
+ Say Y to enable PTP hardware timestamping on Microchip KSZ switch
+ chips that support it.
+
menuconfig NET_DSA_MICROCHIP_KSZ8795
tristate "Microchip KSZ8795 series switch support"
depends on NET_DSA
diff --git a/drivers/net/dsa/microchip/Makefile b/drivers/net/dsa/microchip/Makefile
index c5cc1d5dea06..35c4356bad65 100644
--- a/drivers/net/dsa/microchip/Makefile
+++ b/drivers/net/dsa/microchip/Makefile
@@ -2,6 +2,7 @@
obj-$(CONFIG_NET_DSA_MICROCHIP_KSZ_COMMON) += ksz_common.o
obj-$(CONFIG_NET_DSA_MICROCHIP_KSZ9477) += ksz9477.o
ksz9477-objs := ksz9477_main.o
+ksz9477-$(CONFIG_NET_DSA_MICROCHIP_KSZ9477_PTP) += ksz9477_ptp.o
obj-$(CONFIG_NET_DSA_MICROCHIP_KSZ9477_I2C) += ksz9477_i2c.o
obj-$(CONFIG_NET_DSA_MICROCHIP_KSZ9477_SPI) += ksz9477_spi.o
obj-$(CONFIG_NET_DSA_MICROCHIP_KSZ8795) += ksz8795.o
diff --git a/drivers/net/dsa/microchip/ksz9477_i2c.c b/drivers/net/dsa/microchip/ksz9477_i2c.c
index 4ed1f503044a..315eb24c444d 100644
--- a/drivers/net/dsa/microchip/ksz9477_i2c.c
+++ b/drivers/net/dsa/microchip/ksz9477_i2c.c
@@ -58,7 +58,7 @@ static int ksz9477_i2c_remove(struct i2c_client *i2c)
{
struct ksz_device *dev = i2c_get_clientdata(i2c);

- ksz_switch_remove(dev);
+ ksz9477_switch_remove(dev);

return 0;
}
diff --git a/drivers/net/dsa/microchip/ksz9477_main.c b/drivers/net/dsa/microchip/ksz9477_main.c
index 6b5a981fb21f..7d623400139f 100644
--- a/drivers/net/dsa/microchip/ksz9477_main.c
+++ b/drivers/net/dsa/microchip/ksz9477_main.c
@@ -18,6 +18,7 @@

#include "ksz9477_reg.h"
#include "ksz_common.h"
+#include "ksz9477_ptp.h"

/* Used with variable features to indicate capabilities. */
#define GBIT_SUPPORT BIT(0)
@@ -1719,10 +1720,26 @@ int ksz9477_switch_register(struct ksz_device *dev)
phy_remove_link_mode(phydev,
ETHTOOL_LINK_MODE_1000baseT_Full_BIT);
}
+
+ ret = ksz9477_ptp_init(dev);
+ if (ret)
+ goto error_switch_unregister;
+
+ return 0;
+
+error_switch_unregister:
+ ksz_switch_remove(dev);
return ret;
}
EXPORT_SYMBOL(ksz9477_switch_register);

+void ksz9477_switch_remove(struct ksz_device *dev)
+{
+ ksz9477_ptp_deinit(dev);
+ ksz_switch_remove(dev);
+}
+EXPORT_SYMBOL(ksz9477_switch_remove);
+
MODULE_AUTHOR("Woojung Huh <Woojung.Huh@microchip.com>");
MODULE_DESCRIPTION("Microchip KSZ9477 Series Switch DSA Driver");
MODULE_LICENSE("GPL");
diff --git a/drivers/net/dsa/microchip/ksz9477_ptp.c b/drivers/net/dsa/microchip/ksz9477_ptp.c
new file mode 100644
index 000000000000..44d7bbdea518
--- /dev/null
+++ b/drivers/net/dsa/microchip/ksz9477_ptp.c
@@ -0,0 +1,301 @@
+// SPDX-License-Identifier: GPL-2.0
+/* Microchip KSZ9477 switch driver PTP routines
+ *
+ * Author: Christian Eggers <ceggers@arri.de>
+ *
+ * Copyright (c) 2020 ARRI Lighting
+ */
+
+#include <linux/ptp_clock_kernel.h>
+
+#include "ksz_common.h"
+#include "ksz9477_reg.h"
+
+#include "ksz9477_ptp.h"
+
+#define KSZ_PTP_INC_NS 40 /* HW clock is incremented every 40 ns (by 40) */
+#define KSZ_PTP_SUBNS_BITS 32 /* Number of bits in sub-nanoseconds counter */
+
+/* Posix clock support */
+
+static int ksz9477_ptp_adjfine(struct ptp_clock_info *ptp, long scaled_ppm)
+{
+ struct ksz_device *dev = container_of(ptp, struct ksz_device, ptp_caps);
+ u16 data16;
+ int ret;
+
+ if (scaled_ppm) {
+ /* basic calculation:
+ * s32 ppb = scaled_ppm_to_ppb(scaled_ppm);
+ * s64 adj = div_s64(((s64)ppb * KSZ_PTP_INC_NS) << KSZ_PTP_SUBNS_BITS,
+ * NSEC_PER_SEC);
+ */
+
+ /* more precise calculation (avoids shifting out precision) */
+ s64 ppb, adj;
+ u32 data32;
+
+ /* see scaled_ppm_to_ppb() in ptp_clock.c for details */
+ ppb = 1 + scaled_ppm;
+ ppb *= 125;
+ ppb *= KSZ_PTP_INC_NS;
+ ppb <<= KSZ_PTP_SUBNS_BITS - 13;
+ adj = div_s64(ppb, NSEC_PER_SEC);
+
+ data32 = abs(adj);
+ data32 &= BIT_MASK(30) - 1;
+ if (adj >= 0)
+ data32 |= PTP_RATE_DIR;
+
+ ret = ksz_write32(dev, REG_PTP_SUBNANOSEC_RATE, data32);
+ if (ret)
+ return ret;
+ }
+
+ ret = ksz_read16(dev, REG_PTP_CLK_CTRL, &data16);
+ if (ret)
+ return ret;
+
+ if (scaled_ppm)
+ data16 |= PTP_CLK_ADJ_ENABLE;
+ else
+ data16 &= ~PTP_CLK_ADJ_ENABLE;
+
+ ret = ksz_write16(dev, REG_PTP_CLK_CTRL, data16);
+ if (ret)
+ return ret;
+
+ return 0;
+}
+
+static int ksz9477_ptp_adjtime(struct ptp_clock_info *ptp, s64 delta)
+{
+ struct ksz_device *dev = container_of(ptp, struct ksz_device, ptp_caps);
+ s32 sec, nsec;
+ u16 data16;
+ int ret;
+
+ mutex_lock(&dev->ptp_mutex);
+
+ /* do not use ns_to_timespec64(), both sec and nsec are subtracted by hw */
+ sec = div_s64_rem(delta, NSEC_PER_SEC, &nsec);
+
+ ret = ksz_write32(dev, REG_PTP_RTC_NANOSEC, abs(nsec));
+ if (ret)
+ goto error_return;
+
+ /* contradictory to the data sheet, seconds are also considered */
+ ret = ksz_write32(dev, REG_PTP_RTC_SEC, abs(sec));
+ if (ret)
+ goto error_return;
+
+ ret = ksz_read16(dev, REG_PTP_CLK_CTRL, &data16);
+ if (ret)
+ goto error_return;
+
+ data16 |= PTP_STEP_ADJ;
+ if (delta < 0)
+ data16 &= ~PTP_STEP_DIR; /* 0: subtract */
+ else
+ data16 |= PTP_STEP_DIR; /* 1: add */
+
+ ret = ksz_write16(dev, REG_PTP_CLK_CTRL, data16);
+ if (ret)
+ goto error_return;
+
+error_return:
+ mutex_unlock(&dev->ptp_mutex);
+ return ret;
+}
+
+static int _ksz9477_ptp_gettime(struct ksz_device *dev, struct timespec64 *ts)
+{
+ u32 nanoseconds;
+ u32 seconds;
+ u16 data16;
+ u8 phase;
+ int ret;
+
+ /* Copy current PTP clock into shadow registers */
+ ret = ksz_read16(dev, REG_PTP_CLK_CTRL, &data16);
+ if (ret)
+ return ret;
+
+ data16 |= PTP_READ_TIME;
+
+ ret = ksz_write16(dev, REG_PTP_CLK_CTRL, data16);
+ if (ret)
+ return ret;
+
+ /* Read from shadow registers */
+ ret = ksz_read8(dev, REG_PTP_RTC_SUB_NANOSEC__2, &phase);
+ if (ret)
+ return ret;
+ ret = ksz_read32(dev, REG_PTP_RTC_NANOSEC, &nanoseconds);
+ if (ret)
+ return ret;
+ ret = ksz_read32(dev, REG_PTP_RTC_SEC, &seconds);
+ if (ret)
+ return ret;
+
+ ts->tv_sec = seconds;
+ ts->tv_nsec = nanoseconds + phase * 8;
+
+ return 0;
+}
+
+static int ksz9477_ptp_gettime(struct ptp_clock_info *ptp, struct timespec64 *ts)
+{
+ struct ksz_device *dev = container_of(ptp, struct ksz_device, ptp_caps);
+ int ret;
+
+ mutex_lock(&dev->ptp_mutex);
+ ret = _ksz9477_ptp_gettime(dev, ts);
+ mutex_unlock(&dev->ptp_mutex);
+
+ return ret;
+}
+
+static int ksz9477_ptp_settime(struct ptp_clock_info *ptp, struct timespec64 const *ts)
+{
+ struct ksz_device *dev = container_of(ptp, struct ksz_device, ptp_caps);
+ u16 data16;
+ int ret;
+
+ mutex_lock(&dev->ptp_mutex);
+
+ /* Write to shadow registers */
+
+ /* clock phase */
+ ret = ksz_read16(dev, REG_PTP_RTC_SUB_NANOSEC__2, &data16);
+ if (ret)
+ goto error_return;
+
+ data16 &= ~PTP_RTC_SUB_NANOSEC_M;
+
+ ret = ksz_write16(dev, REG_PTP_RTC_SUB_NANOSEC__2, data16);
+ if (ret)
+ goto error_return;
+
+ /* nanoseconds */
+ ret = ksz_write32(dev, REG_PTP_RTC_NANOSEC, ts->tv_nsec);
+ if (ret)
+ goto error_return;
+
+ /* seconds */
+ ret = ksz_write32(dev, REG_PTP_RTC_SEC, ts->tv_sec);
+ if (ret)
+ goto error_return;
+
+ /* Load PTP clock from shadow registers */
+ ret = ksz_read16(dev, REG_PTP_CLK_CTRL, &data16);
+ if (ret)
+ goto error_return;
+
+ data16 |= PTP_LOAD_TIME;
+
+ ret = ksz_write16(dev, REG_PTP_CLK_CTRL, data16);
+ if (ret)
+ goto error_return;
+
+error_return:
+ mutex_unlock(&dev->ptp_mutex);
+ return ret;
+}
+
+static int ksz9477_ptp_enable(struct ptp_clock_info *ptp, struct ptp_clock_request *req, int on)
+{
+ return -ENOTTY;
+}
+
+static int ksz9477_ptp_start_clock(struct ksz_device *dev)
+{
+ u16 data;
+ int ret;
+
+ ret = ksz_read16(dev, REG_PTP_CLK_CTRL, &data);
+ if (ret)
+ return ret;
+
+ /* Perform PTP clock reset */
+ data |= PTP_CLK_RESET;
+ ret = ksz_write16(dev, REG_PTP_CLK_CTRL, data);
+ if (ret)
+ return ret;
+ data &= ~PTP_CLK_RESET;
+
+ /* Enable PTP clock */
+ data |= PTP_CLK_ENABLE;
+ ret = ksz_write16(dev, REG_PTP_CLK_CTRL, data);
+ if (ret)
+ return ret;
+
+ return 0;
+}
+
+static int ksz9477_ptp_stop_clock(struct ksz_device *dev)
+{
+ u16 data;
+ int ret;
+
+ ret = ksz_read16(dev, REG_PTP_CLK_CTRL, &data);
+ if (ret)
+ return ret;
+
+ /* Disable PTP clock */
+ data &= ~PTP_CLK_ENABLE;
+ ret = ksz_write16(dev, REG_PTP_CLK_CTRL, data);
+ if (ret)
+ return ret;
+
+ return 0;
+}
+
+int ksz9477_ptp_init(struct ksz_device *dev)
+{
+ int ret;
+
+ mutex_init(&dev->ptp_mutex);
+
+ /* PTP clock properties */
+
+ dev->ptp_caps.owner = THIS_MODULE;
+ snprintf(dev->ptp_caps.name, sizeof(dev->ptp_caps.name), dev_name(dev->dev));
+
+ /* Sub-nanoseconds-adj,max * sub-nanoseconds / 40ns * 1ns
+ * = (2^30-1) * (2 ^ 32) / 40 ns * 1 ns = 6249999
+ */
+ dev->ptp_caps.max_adj = 6249999;
+ dev->ptp_caps.n_alarm = 0;
+ dev->ptp_caps.n_ext_ts = 0; /* currently not implemented */
+ dev->ptp_caps.n_per_out = 0;
+ dev->ptp_caps.pps = 0;
+ dev->ptp_caps.adjfine = ksz9477_ptp_adjfine;
+ dev->ptp_caps.adjtime = ksz9477_ptp_adjtime;
+ dev->ptp_caps.gettime64 = ksz9477_ptp_gettime;
+ dev->ptp_caps.settime64 = ksz9477_ptp_settime;
+ dev->ptp_caps.enable = ksz9477_ptp_enable;
+
+ /* Start hardware counter (will overflow after 136 years) */
+ ret = ksz9477_ptp_start_clock(dev);
+ if (ret)
+ return ret;
+
+ dev->ptp_clock = ptp_clock_register(&dev->ptp_caps, dev->dev);
+ if (IS_ERR(dev->ptp_clock)) {
+ ret = PTR_ERR(dev->ptp_clock);
+ goto error_stop_clock;
+ }
+
+ return 0;
+
+error_stop_clock:
+ ksz9477_ptp_stop_clock(dev);
+ return ret;
+}
+
+void ksz9477_ptp_deinit(struct ksz_device *dev)
+{
+ ptp_clock_unregister(dev->ptp_clock);
+ ksz9477_ptp_stop_clock(dev);
+}
diff --git a/drivers/net/dsa/microchip/ksz9477_ptp.h b/drivers/net/dsa/microchip/ksz9477_ptp.h
new file mode 100644
index 000000000000..0076538419fa
--- /dev/null
+++ b/drivers/net/dsa/microchip/ksz9477_ptp.h
@@ -0,0 +1,27 @@
+/* SPDX-License-Identifier: GPL-2.0
+ *
+ * Microchip KSZ9477 switch driver PTP routines
+ *
+ * Author: Christian Eggers <ceggers@arri.de>
+ *
+ * Copyright (c) 2020 ARRI Lighting
+ */
+
+#ifndef DRIVERS_NET_DSA_MICROCHIP_KSZ9477_PTP_H_
+#define DRIVERS_NET_DSA_MICROCHIP_KSZ9477_PTP_H_
+
+#include "ksz_common.h"
+
+#if IS_ENABLED(CONFIG_NET_DSA_MICROCHIP_KSZ9477_PTP)
+
+int ksz9477_ptp_init(struct ksz_device *dev);
+void ksz9477_ptp_deinit(struct ksz_device *dev);
+
+#else
+
+static inline int ksz9477_ptp_init(struct ksz_device *dev) { return 0; }
+static inline void ksz9477_ptp_deinit(struct ksz_device *dev) {}
+
+#endif
+
+#endif /* DRIVERS_NET_DSA_MICROCHIP_KSZ9477_PTP_H_ */
diff --git a/drivers/net/dsa/microchip/ksz9477_spi.c b/drivers/net/dsa/microchip/ksz9477_spi.c
index d2eea9596e53..e49d581547ac 100644
--- a/drivers/net/dsa/microchip/ksz9477_spi.c
+++ b/drivers/net/dsa/microchip/ksz9477_spi.c
@@ -66,7 +66,7 @@ static int ksz9477_spi_remove(struct spi_device *spi)
struct ksz_device *dev = spi_get_drvdata(spi);

if (dev)
- ksz_switch_remove(dev);
+ ksz9477_switch_remove(dev);

return 0;
}
diff --git a/drivers/net/dsa/microchip/ksz_common.h b/drivers/net/dsa/microchip/ksz_common.h
index 5735374b5bc3..96808d2585d9 100644
--- a/drivers/net/dsa/microchip/ksz_common.h
+++ b/drivers/net/dsa/microchip/ksz_common.h
@@ -67,6 +67,7 @@ void ksz_switch_remove(struct ksz_device *dev);

int ksz8795_switch_register(struct ksz_device *dev);
int ksz9477_switch_register(struct ksz_device *dev);
+void ksz9477_switch_remove(struct ksz_device *dev);

void ksz_update_port_member(struct ksz_device *dev, int port);
void ksz_init_mib_timer(struct ksz_device *dev);
diff --git a/include/linux/dsa/ksz_common.h b/include/linux/dsa/ksz_common.h
index bf57ba4b2132..4d5b6cc9429a 100644
--- a/include/linux/dsa/ksz_common.h
+++ b/include/linux/dsa/ksz_common.h
@@ -9,6 +9,7 @@
#include <linux/kernel.h>
#include <linux/mutex.h>
#include <linux/phy.h>
+#include <linux/ptp_clock_kernel.h>
#include <linux/regmap.h>
#include <linux/timer.h>
#include <linux/workqueue.h>
@@ -92,6 +93,12 @@ struct ksz_device {
u32 overrides; /* chip functions set by user */
u16 host_mask;
u16 port_mask;
+
+#if IS_ENABLED(CONFIG_NET_DSA_MICROCHIP_KSZ9477_PTP)
+ struct ptp_clock *ptp_clock;
+ struct ptp_clock_info ptp_caps;
+ struct mutex ptp_mutex;
+#endif
};

#endif /* _NET_DSA_KSZ_COMMON_H_ */
--
Christian Eggers
Embedded software developer

Arnold & Richter Cine Technik GmbH & Co. Betriebs KG
Sitz: Muenchen - Registergericht: Amtsgericht Muenchen - Handelsregisternummer: HRA 57918
Persoenlich haftender Gesellschafter: Arnold & Richter Cine Technik GmbH
Sitz: Muenchen - Registergericht: Amtsgericht Muenchen - Handelsregisternummer: HRB 54477
Geschaeftsfuehrer: Dr. Michael Neuhaeuser; Stephan Schenk; Walter Trauninger; Markus Zeiler