[RFC PATCH net-next 8/9] net: dsa: microchip: ksz9477: add Pulse Per Second (PPS) support

Christian Eggers
2020-10-19T17:36:39Z

The KSZ9563 has a Trigger Output Unit (TOU) which can be used to
generate periodic signals.

After adjusting the PTP clock time, the PPS signal has to be restarted.

Tested on a Microchip KSZ9563 switch.

Signed-off-by: Christian Eggers <ceggers@arri.de>
---
drivers/net/dsa/microchip/ksz9477_ptp.c | 251 +++++++++++++++++++++++-
drivers/net/dsa/microchip/ksz9477_ptp.h | 2 +
include/linux/dsa/ksz_common.h | 6 +
3 files changed, 257 insertions(+), 2 deletions(-)

diff --git a/drivers/net/dsa/microchip/ksz9477_ptp.c b/drivers/net/dsa/microchip/ksz9477_ptp.c
index d4bcfff0577e..6f7df077bc72 100644
--- a/drivers/net/dsa/microchip/ksz9477_ptp.c
+++ b/drivers/net/dsa/microchip/ksz9477_ptp.c
@@ -19,6 +19,126 @@
#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 */

+/* Shared register access routines (Trigger Output Unit) */
+
+static int ksz9477_ptp_tou_reset(struct ksz_device *dev, unsigned int unit)
+{
+ u32 ctrl_stat, data;
+ int ret;
+
+ /* Reset trigger unit (clears TRIGGER_EN, but not GPIOSTATx) */
+ ret = ksz_read32(dev, REG_PTP_CTRL_STAT__4, &ctrl_stat);
+ if (ret)
+ return ret;
+
+ ctrl_stat |= TRIG_RESET;
+
+ ret = ksz_write32(dev, REG_PTP_CTRL_STAT__4, ctrl_stat);
+ if (ret)
+ return ret;
+
+ /* Clear DONE */
+ data = 1 << (unit + TRIG_DONE_S);
+ ret = ksz_write32(dev, REG_PTP_TRIG_STATUS__4, data);
+ if (ret)
+ return ret;
+
+ /* Clear IRQ */
+ data = 1 << (unit + TRIG_INT_S);
+ ret = ksz_write32(dev, REG_PTP_INT_STATUS__4, data);
+ if (ret)
+ return ret;
+
+ /* Clear reset and set GPIO direction */
+ ctrl_stat &= ~TRIG_ENABLE; /* clear cached bit :-) */
+ ctrl_stat &= ~TRIG_RESET;
+
+ ret = ksz_write32(dev, REG_PTP_CTRL_STAT__4, ctrl_stat);
+ if (ret)
+ return ret;
+
+ return 0;
+}
+
+static int ksz9477_ptp_tou_cycle_width_set(struct ksz_device *dev, u32 width_ns)
+{
+ int ret;
+
+ ret = ksz_write32(dev, REG_TRIG_CYCLE_WIDTH, width_ns);
+ if (ret)
+ return ret;
+
+ return 0;
+}
+
+static int ksz9477_ptp_tou_cycle_count_set(struct ksz_device *dev, u16 count)
+{
+ u32 data;
+ int ret;
+
+ ret = ksz_read32(dev, REG_TRIG_CYCLE_CNT, &data);
+ if (ret)
+ return ret;
+
+ data &= ~(TRIG_CYCLE_CNT_M << TRIG_CYCLE_CNT_S);
+ data |= (count & TRIG_CYCLE_CNT_M) << TRIG_CYCLE_CNT_S;
+
+ ret = ksz_write32(dev, REG_TRIG_CYCLE_CNT, data);
+ if (ret)
+ return ret;
+
+ return 0;
+}
+
+static int ksz9477_ptp_tou_pulse_set(struct ksz_device *dev, u32 pulse_ns)
+{
+ u32 data;
+
+ data = (pulse_ns / 8);
+
+ return ksz_write32(dev, REG_TRIG_PULSE_WIDTH__4, data);
+}
+
+static int ksz9477_ptp_tou_target_time_set(struct ksz_device *dev, struct timespec64 const *ts)
+{
+ int ret;
+
+ /* Hardware has only 32 bit */
+ if ((ts->tv_sec & 0xffffffff) != ts->tv_sec)
+ return -EINVAL;
+
+ ret = ksz_write32(dev, REG_TRIG_TARGET_NANOSEC, ts->tv_nsec);
+ if (ret)
+ return ret;
+
+ ret = ksz_write32(dev, REG_TRIG_TARGET_SEC, ts->tv_sec);
+ if (ret)
+ return ret;
+
+ return 0;
+}
+
+static int ksz9477_ptp_tou_start(struct ksz_device *dev, u32 *ctrl_stat_)
+{
+ u32 ctrl_stat;
+ int ret;
+
+ ret = ksz_read32(dev, REG_PTP_CTRL_STAT__4, &ctrl_stat);
+ if (ret)
+ return ret;
+
+ ctrl_stat |= TRIG_ENABLE;
+
+ ret = ksz_write32(dev, REG_PTP_CTRL_STAT__4, ctrl_stat);
+ if (ret)
+ return ret;
+
+ if (ctrl_stat_)
+ *ctrl_stat_ = ctrl_stat;
+
+ return 0;
+}
+
/* Posix clock support */

static int ksz9477_ptp_adjfine(struct ptp_clock_info *ptp, long scaled_ppm)
@@ -71,6 +191,8 @@ static int ksz9477_ptp_adjfine(struct ptp_clock_info *ptp, long scaled_ppm)
return 0;
}

+static int ksz9477_ptp_enable_pps(struct ksz_device *dev, int on);
+
static int ksz9477_ptp_adjtime(struct ptp_clock_info *ptp, s64 delta)
{
struct ksz_device *dev = container_of(ptp, struct ksz_device, ptp_caps);
@@ -108,6 +230,20 @@ static int ksz9477_ptp_adjtime(struct ptp_clock_info *ptp, s64 delta)
if (ret)
goto error_return;

+ switch (dev->ptp_tou_mode) {
+ case KSZ_PTP_TOU_IDLE:
+ break;
+
+ case KSZ_PTP_TOU_PPS:
+ dev_info(dev->dev, "Restarting PPS\n");
+
+ ret = ksz9477_ptp_enable_pps(dev, 1);
+ if (ret)
+ goto error_return;
+
+ break;
+ }
+
spin_lock_irqsave(&dev->ptp_clock_lock, flags);
dev->ptp_clock_time = timespec64_add(dev->ptp_clock_time, delta64);
spin_unlock_irqrestore(&dev->ptp_clock_lock, flags);
@@ -208,6 +344,20 @@ static int ksz9477_ptp_settime(struct ptp_clock_info *ptp, struct timespec64 con
if (ret)
goto error_return;

+ switch (dev->ptp_tou_mode) {
+ case KSZ_PTP_TOU_IDLE:
+ break;
+
+ case KSZ_PTP_TOU_PPS:
+ dev_info(dev->dev, "Restarting PPS\n");
+
+ ret = ksz9477_ptp_enable_pps(dev, 1);
+ if (ret)
+ goto error_return;
+
+ break;
+ }
+
spin_lock_irqsave(&dev->ptp_clock_lock, flags);
dev->ptp_clock_time = *ts;
spin_unlock_irqrestore(&dev->ptp_clock_lock, flags);
@@ -217,9 +367,106 @@ static int ksz9477_ptp_settime(struct ptp_clock_info *ptp, struct timespec64 con
return ret;
}

+#define KSZ9477_PPS_TOU 0 /* currently fixed to trigger output unit 0 */
+
+static int ksz9477_ptp_enable_pps(struct ksz_device *dev, int on)
+{
+ struct timespec64 now, pps_start, diff;
+ u32 gpio_stat0, trig_ctrl;
+ int ret;
+
+ if (dev->ptp_tou_mode != KSZ_PTP_TOU_PPS && dev->ptp_tou_mode != KSZ_PTP_TOU_IDLE)
+ return -EBUSY;
+
+ /* Reset trigger unit 0 */
+ ret = ksz9477_ptp_tou_reset(dev, KSZ9477_PPS_TOU);
+ if (ret)
+ return ret;
+
+ if (!on) {
+ dev->ptp_tou_mode = KSZ_PTP_TOU_IDLE;
+ return 0; /* success */
+ }
+
+ /* Enable notify, set rising edge, set periodic pulse pattern */
+ trig_ctrl = TRIG_NOTIFY | (TRIG_POS_PERIOD << TRIG_PATTERN_S);
+
+ ret = ksz_write32(dev, REG_TRIG_CTRL__4, trig_ctrl);
+ if (ret)
+ return ret;
+
+ /* Set cycle width (1 s) */
+ ret = ksz9477_ptp_tou_cycle_width_set(dev, NSEC_PER_SEC);
+ if (ret)
+ return ret;
+
+ /* Set cycle count (infinite) */
+ ksz9477_ptp_tou_cycle_count_set(dev, 0);
+ if (ret)
+ return ret;
+
+ /* Set pulse with (125 ms / 8 ns) */
+ ret = ksz9477_ptp_tou_pulse_set(dev, 125000000);
+ if (ret)
+ return ret;
+
+ /* Read current time */
+ ret = _ksz9477_ptp_gettime(dev, &now);
+ if (ret)
+ return ret;
+
+ /* Determine and write start time of PPS */
+ pps_start.tv_sec = now.tv_sec + 1;
+ pps_start.tv_nsec = 0;
+ diff = timespec64_sub(pps_start, now);
+
+ /* Reserve at least 100 ms for programming and activating */
+ if (diff.tv_nsec < 100000000)
+ pps_start.tv_sec++;
+
+ ret = ksz9477_ptp_tou_target_time_set(dev, &pps_start);
+ if (ret)
+ return ret;
+
+ /* Activate trigger unit */
+ ret = ksz9477_ptp_tou_start(dev, NULL);
+ if (ret)
+ return ret;
+
+ /* Check error flag:
+ * - the ACTIVE flag is NOT cleared an error!
+ */
+ ret = ksz_read32(dev, REG_PTP_TRIG_STATUS__4, &gpio_stat0);
+ if (ret)
+ return ret;
+
+ if (gpio_stat0 & (1 << (KSZ9477_PPS_TOU + TRIG_ERROR_S))) {
+ dev_err(dev->dev, "%s: Trigger unit error!\n", __func__);
+ ret = -EIO;
+ /* Unit will be reset on next access */
+ return ret;
+ }
+
+ dev->ptp_tou_mode = KSZ_PTP_TOU_PPS;
+ return 0;
+}
+
static int ksz9477_ptp_enable(struct ptp_clock_info *ptp, struct ptp_clock_request *req, int on)
{
- return -ENOTTY;
+ struct ksz_device *dev = container_of(ptp, struct ksz_device, ptp_caps);
+ int ret;
+
+ switch (req->type) {
+ case PTP_CLK_REQ_PPS:
+ mutex_lock(&dev->ptp_mutex);
+ ret = ksz9477_ptp_enable_pps(dev, on);
+ mutex_unlock(&dev->ptp_mutex);
+ return ret;
+ default:
+ return -EINVAL;
+ }
+
+ return 0;
}

static long ksz9477_ptp_do_aux_work(struct ptp_clock_info *ptp)
@@ -644,7 +891,7 @@ int ksz9477_ptp_init(struct ksz_device *dev)
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.pps = 1;
dev->ptp_caps.adjfine = ksz9477_ptp_adjfine;
dev->ptp_caps.adjtime = ksz9477_ptp_adjtime;
dev->ptp_caps.gettime64 = ksz9477_ptp_gettime;
diff --git a/drivers/net/dsa/microchip/ksz9477_ptp.h b/drivers/net/dsa/microchip/ksz9477_ptp.h
index e8d50a086311..03058e795678 100644
--- a/drivers/net/dsa/microchip/ksz9477_ptp.h
+++ b/drivers/net/dsa/microchip/ksz9477_ptp.h
@@ -20,6 +20,7 @@
int ksz9477_ptp_init(struct ksz_device *dev);
void ksz9477_ptp_deinit(struct ksz_device *dev);

+irqreturn_t ksz9477_ptp_interrupt(struct ksz_device *dev);
irqreturn_t ksz9477_ptp_port_interrupt(struct ksz_device *dev, int port);

int ksz9477_ptp_get_ts_info(struct dsa_switch *ds, int port, struct ethtool_ts_info *ts);
@@ -33,6 +34,7 @@ bool ksz9477_ptp_port_txtstamp(struct dsa_switch *ds, int port, struct sk_buff *
static inline int ksz9477_ptp_init(struct ksz_device *dev) { return 0; }
static inline void ksz9477_ptp_deinit(struct ksz_device *dev) {}

+static inline irqreturn_t ksz9477_ptp_interrupt(struct ksz_device *dev) { return IRQ_NONE; }
static inline irqreturn_t ksz9477_ptp_port_interrupt(struct ksz_device *dev, int port)
{ return IRQ_NONE; }

diff --git a/include/linux/dsa/ksz_common.h b/include/linux/dsa/ksz_common.h
index 10b42154ba5a..f1014b40d643 100644
--- a/include/linux/dsa/ksz_common.h
+++ b/include/linux/dsa/ksz_common.h
@@ -58,6 +58,11 @@ struct ksz_port {
#endif
};

+enum ksz_ptp_tou_mode {
+ KSZ_PTP_TOU_IDLE,
+ KSZ_PTP_TOU_PPS,
+};
+
struct ksz_device {
struct dsa_switch *ds;
struct ksz_platform_data *pdata;
@@ -116,6 +121,7 @@ struct ksz_device {
spinlock_t ptp_clock_lock; /* for ptp_clock_time */
/* approximated current time, read once per second from hardware */
struct timespec64 ptp_clock_time;
+ enum ksz_ptp_tou_mode ptp_tou_mode;
#endif
};

--
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