From 03260b5a80fb5ca10fb7bd9b0943e10aa71949a3 Mon Sep 17 00:00:00 2001 From: Russell King Date: Thu, 23 Jul 2020 15:45:06 +0100 Subject: net: mvpp2: ptp: add TAI support Add support for the TAI block in the mvpp2.2 hardware. Acked-by: Richard Cochran Signed-off-by: Russell King --- drivers/net/ethernet/marvell/mvpp2/mvpp2_tai.c | 400 +++++++++++++++++++++++++ 1 file changed, 400 insertions(+) create mode 100644 drivers/net/ethernet/marvell/mvpp2/mvpp2_tai.c (limited to 'drivers/net/ethernet/marvell/mvpp2/mvpp2_tai.c') diff --git a/drivers/net/ethernet/marvell/mvpp2/mvpp2_tai.c b/drivers/net/ethernet/marvell/mvpp2/mvpp2_tai.c new file mode 100644 index 000000000000..86c94ca97e43 --- /dev/null +++ b/drivers/net/ethernet/marvell/mvpp2/mvpp2_tai.c @@ -0,0 +1,400 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Marvell PP2.2 TAI support + * + * Note: + * Do NOT use the event capture support. + * Do Not even set the MPP muxes to allow PTP_EVENT_REQ to be used. + * It will disrupt the operation of this driver, and there is nothing + * that this driver can do to prevent that. Even using PTP_EVENT_REQ + * as an output will be seen as a trigger input, which can't be masked. + * When ever a trigger input is seen, the action in the TCFCR0_TCF + * field will be performed - whether it is a set, increment, decrement + * read, or frequency update. + * + * Other notes (useful, not specified in the documentation): + * - PTP_PULSE_OUT (PTP_EVENT_REQ MPP) + * It looks like the hardware can't generate a pulse at nsec=0. (The + * output doesn't trigger if the nsec field is zero.) + * Note: when configured as an output via the register at 0xfX441120, + * the input is still very much alive, and will trigger the current TCF + * function. + * - PTP_CLK_OUT (PTP_TRIG_GEN MPP) + * This generates a "PPS" signal determined by the CCC registers. It + * seems this is not aligned to the TOD counter in any way (it may be + * initially, but if you specify a non-round second interval, it won't, + * and you can't easily get it back.) + * - PTP_PCLK_OUT + * This generates a 50% duty cycle clock based on the TOD counter, and + * seems it can be set to any period of 1ns resolution. It is probably + * limited by the TOD step size. Its period is defined by the PCLK_CCC + * registers. Again, its alignment to the second is questionable. + * + * Consequently, we support none of these. + */ +#include +#include +#include + +#include "mvpp2.h" + +#define CR0_SW_NRESET BIT(0) + +#define TCFCR0_PHASE_UPDATE_ENABLE BIT(8) +#define TCFCR0_TCF_MASK (7 << 2) +#define TCFCR0_TCF_UPDATE (0 << 2) +#define TCFCR0_TCF_FREQUPDATE (1 << 2) +#define TCFCR0_TCF_INCREMENT (2 << 2) +#define TCFCR0_TCF_DECREMENT (3 << 2) +#define TCFCR0_TCF_CAPTURE (4 << 2) +#define TCFCR0_TCF_NOP (7 << 2) +#define TCFCR0_TCF_TRIGGER BIT(0) + +#define TCSR_CAPTURE_1_VALID BIT(1) +#define TCSR_CAPTURE_0_VALID BIT(0) + +struct mvpp2_tai { + struct ptp_clock_info caps; + struct ptp_clock *ptp_clock; + void __iomem *base; + spinlock_t lock; + u64 period; // nanosecond period in 32.32 fixed point +}; + +static void mvpp2_tai_modify(void __iomem *reg, u32 mask, u32 set) +{ + u32 val; + + val = readl_relaxed(reg) & ~mask; + val |= set & mask; + writel(val, reg); +} + +static void mvpp2_tai_write(u32 val, void __iomem *reg) +{ + writel_relaxed(val & 0xffff, reg); +} + +static u32 mvpp2_tai_read(void __iomem *reg) +{ + return readl_relaxed(reg) & 0xffff; +} + +static struct mvpp2_tai *ptp_to_tai(struct ptp_clock_info *ptp) +{ + return container_of(ptp, struct mvpp2_tai, caps); +} + +static void mvpp22_tai_read_ts(struct timespec64 *ts, void __iomem *base) +{ + ts->tv_sec = (u64)mvpp2_tai_read(base + 0) << 32 | + mvpp2_tai_read(base + 4) << 16 | + mvpp2_tai_read(base + 8); + + ts->tv_nsec = mvpp2_tai_read(base + 12) << 16 | + mvpp2_tai_read(base + 16); + + /* Read and discard fractional part */ + readl_relaxed(base + 20); + readl_relaxed(base + 24); +} + +static void mvpp2_tai_write_tlv(const struct timespec64 *ts, u32 frac, + void __iomem *base) +{ + mvpp2_tai_write(ts->tv_sec >> 32, base + MVPP22_TAI_TLV_SEC_HIGH); + mvpp2_tai_write(ts->tv_sec >> 16, base + MVPP22_TAI_TLV_SEC_MED); + mvpp2_tai_write(ts->tv_sec, base + MVPP22_TAI_TLV_SEC_LOW); + mvpp2_tai_write(ts->tv_nsec >> 16, base + MVPP22_TAI_TLV_NANO_HIGH); + mvpp2_tai_write(ts->tv_nsec, base + MVPP22_TAI_TLV_NANO_LOW); + mvpp2_tai_write(frac >> 16, base + MVPP22_TAI_TLV_FRAC_HIGH); + mvpp2_tai_write(frac, base + MVPP22_TAI_TLV_FRAC_LOW); +} + +static void mvpp2_tai_op(u32 op, void __iomem *base) +{ + /* Trigger the operation. Note that an external unmaskable + * event on PTP_EVENT_REQ will also trigger this action. + */ + mvpp2_tai_modify(base + MVPP22_TAI_TCFCR0, + TCFCR0_TCF_MASK | TCFCR0_TCF_TRIGGER, + op | TCFCR0_TCF_TRIGGER); + mvpp2_tai_modify(base + MVPP22_TAI_TCFCR0, TCFCR0_TCF_MASK, + TCFCR0_TCF_NOP); +} + +/* The adjustment has a range of +0.5ns to -0.5ns in 2^32 steps, so has units + * of 2^-32 ns. + * + * units(s) = 1 / (2^32 * 10^9) + * fractional = abs_scaled_ppm / (2^16 * 10^6) + * + * What we want to achieve: + * freq_adjusted = freq_nominal * (1 + fractional) + * freq_delta = freq_adjusted - freq_nominal => positive = faster + * freq_delta = freq_nominal * (1 + fractional) - freq_nominal + * So: freq_delta = freq_nominal * fractional + * + * However, we are dealing with periods, so: + * period_adjusted = period_nominal / (1 + fractional) + * period_delta = period_nominal - period_adjusted => positive = faster + * period_delta = period_nominal * fractional / (1 + fractional) + * + * Hence: + * period_delta = period_nominal * abs_scaled_ppm / + * (2^16 * 10^6 + abs_scaled_ppm) + * + * To avoid overflow, we reduce both sides of the divide operation by a factor + * of 16. + */ +static u64 mvpp22_calc_frac_ppm(struct mvpp2_tai *tai, long abs_scaled_ppm) +{ + u64 val = tai->period * abs_scaled_ppm >> 4; + + return div_u64(val, (1000000 << 12) + (abs_scaled_ppm >> 4)); +} + +static s32 mvpp22_calc_max_adj(struct mvpp2_tai *tai) +{ + return 1000000; +} + +static int mvpp22_tai_adjfine(struct ptp_clock_info *ptp, long scaled_ppm) +{ + struct mvpp2_tai *tai = ptp_to_tai(ptp); + unsigned long flags; + void __iomem *base; + bool neg_adj; + s32 frac; + u64 val; + + neg_adj = scaled_ppm < 0; + if (neg_adj) + scaled_ppm = -scaled_ppm; + + val = mvpp22_calc_frac_ppm(tai, scaled_ppm); + + /* Convert to a signed 32-bit adjustment */ + if (neg_adj) { + /* -S32_MIN warns, -val < S32_MIN fails, so go for the easy + * solution. + */ + if (val > 0x80000000) + return -ERANGE; + + frac = -val; + } else { + if (val > S32_MAX) + return -ERANGE; + + frac = val; + } + + base = tai->base; + spin_lock_irqsave(&tai->lock, flags); + mvpp2_tai_write(frac >> 16, base + MVPP22_TAI_TLV_FRAC_HIGH); + mvpp2_tai_write(frac, base + MVPP22_TAI_TLV_FRAC_LOW); + mvpp2_tai_op(TCFCR0_TCF_FREQUPDATE, base); + spin_unlock_irqrestore(&tai->lock, flags); + + return 0; +} + +static int mvpp22_tai_adjtime(struct ptp_clock_info *ptp, s64 delta) +{ + struct mvpp2_tai *tai = ptp_to_tai(ptp); + struct timespec64 ts; + unsigned long flags; + void __iomem *base; + u32 tcf; + + /* We can't deal with S64_MIN */ + if (delta == S64_MIN) + return -ERANGE; + + if (delta < 0) { + delta = -delta; + tcf = TCFCR0_TCF_DECREMENT; + } else { + tcf = TCFCR0_TCF_INCREMENT; + } + + ts = ns_to_timespec64(delta); + + base = tai->base; + spin_lock_irqsave(&tai->lock, flags); + mvpp2_tai_write_tlv(&ts, 0, base); + mvpp2_tai_op(tcf, base); + spin_unlock_irqrestore(&tai->lock, flags); + + return 0; +} + +static int mvpp22_tai_gettimex64(struct ptp_clock_info *ptp, + struct timespec64 *ts, + struct ptp_system_timestamp *sts) +{ + struct mvpp2_tai *tai = ptp_to_tai(ptp); + unsigned long flags; + void __iomem *base; + u32 tcsr; + int ret; + + base = tai->base; + spin_lock_irqsave(&tai->lock, flags); + /* XXX: the only way to read the PTP time is for the CPU to trigger + * an event. However, there is no way to distinguish between the CPU + * triggered event, and an external event on PTP_EVENT_REQ. So this + * is incompatible with external use of PTP_EVENT_REQ. + */ + ptp_read_system_prets(sts); + mvpp2_tai_modify(base + MVPP22_TAI_TCFCR0, + TCFCR0_TCF_MASK | TCFCR0_TCF_TRIGGER, + TCFCR0_TCF_CAPTURE | TCFCR0_TCF_TRIGGER); + ptp_read_system_postts(sts); + mvpp2_tai_modify(base + MVPP22_TAI_TCFCR0, TCFCR0_TCF_MASK, + TCFCR0_TCF_NOP); + + tcsr = readl(base + MVPP22_TAI_TCSR); + if (tcsr & TCSR_CAPTURE_1_VALID) { + mvpp22_tai_read_ts(ts, base + MVPP22_TAI_TCV1_SEC_HIGH); + ret = 0; + } else if (tcsr & TCSR_CAPTURE_0_VALID) { + mvpp22_tai_read_ts(ts, base + MVPP22_TAI_TCV0_SEC_HIGH); + ret = 0; + } else { + /* We don't seem to have a reading... */ + ret = -EBUSY; + } + spin_unlock_irqrestore(&tai->lock, flags); + + return ret; +} + +static int mvpp22_tai_settime64(struct ptp_clock_info *ptp, + const struct timespec64 *ts) +{ + struct mvpp2_tai *tai = ptp_to_tai(ptp); + unsigned long flags; + void __iomem *base; + + base = tai->base; + spin_lock_irqsave(&tai->lock, flags); + mvpp2_tai_write_tlv(ts, 0, base); + + /* Trigger an update to load the value from the TLV registers + * into the TOD counter. Note that an external unmaskable event on + * PTP_EVENT_REQ will also trigger this action. + */ + mvpp2_tai_modify(base + MVPP22_TAI_TCFCR0, + TCFCR0_PHASE_UPDATE_ENABLE | + TCFCR0_TCF_MASK | TCFCR0_TCF_TRIGGER, + TCFCR0_TCF_UPDATE | TCFCR0_TCF_TRIGGER); + mvpp2_tai_modify(base + MVPP22_TAI_TCFCR0, TCFCR0_TCF_MASK, + TCFCR0_TCF_NOP); + spin_unlock_irqrestore(&tai->lock, flags); + + return 0; +} + +static void mvpp22_tai_set_step(struct mvpp2_tai *tai) +{ + void __iomem *base = tai->base; + u32 nano, frac; + + nano = upper_32_bits(tai->period); + frac = lower_32_bits(tai->period); + + /* As the fractional nanosecond is a signed offset, if the MSB (sign) + * bit is set, we have to increment the whole nanoseconds. + */ + if (frac >= 0x80000000) + nano += 1; + + mvpp2_tai_write(nano, base + MVPP22_TAI_TOD_STEP_NANO_CR); + mvpp2_tai_write(frac >> 16, base + MVPP22_TAI_TOD_STEP_FRAC_HIGH); + mvpp2_tai_write(frac, base + MVPP22_TAI_TOD_STEP_FRAC_LOW); +} + +static void mvpp22_tai_init(struct mvpp2_tai *tai) +{ + void __iomem *base = tai->base; + + mvpp22_tai_set_step(tai); + + /* Release the TAI reset */ + mvpp2_tai_modify(base + MVPP22_TAI_CR0, CR0_SW_NRESET, CR0_SW_NRESET); +} + +static void mvpp22_tai_remove(void *priv) +{ + struct mvpp2_tai *tai = priv; + + if (!IS_ERR(tai->ptp_clock)) + ptp_clock_unregister(tai->ptp_clock); +} + +int mvpp22_tai_probe(struct device *dev, struct mvpp2 *priv) +{ + struct mvpp2_tai *tai; + int ret; + + tai = devm_kzalloc(dev, sizeof(*tai), GFP_KERNEL); + if (!tai) + return -ENOMEM; + + spin_lock_init(&tai->lock); + + tai->base = priv->iface_base; + + /* The step size consists of three registers - a 16-bit nanosecond step + * size, and a 32-bit fractional nanosecond step size split over two + * registers. The fractional nanosecond step size has units of 2^-32ns. + * + * To calculate this, we calculate: + * (10^9 + freq / 2) / (freq * 2^-32) + * which gives us the nanosecond step to the nearest integer in 16.32 + * fixed point format, and the fractional part of the step size with + * the MSB inverted. With rounding of the fractional nanosecond, and + * simplification, this becomes: + * (10^9 << 32 + freq << 31 + (freq + 1) >> 1) / freq + * + * So: + * div = (10^9 << 32 + freq << 31 + (freq + 1) >> 1) / freq + * nano = upper_32_bits(div); + * frac = lower_32_bits(div) ^ 0x80000000; + * Will give the values for the registers. + * + * This is all seems perfect, but alas it is not when considering the + * whole story. The system is clocked from 25MHz, which is multiplied + * by a PLL to 1GHz, and then divided by three, giving 333333333Hz + * (recurring). This gives exactly 3ns, but using 333333333Hz with + * the above gives an error of 13*2^-32ns. + * + * Consequently, we use the period rather than calculating from the + * frequency. + */ + tai->period = 3ULL << 32; + + mvpp22_tai_init(tai); + + tai->caps.owner = THIS_MODULE; + strscpy(tai->caps.name, "Marvell PP2.2", sizeof(tai->caps.name)); + tai->caps.max_adj = mvpp22_calc_max_adj(tai); + tai->caps.adjfine = mvpp22_tai_adjfine; + tai->caps.adjtime = mvpp22_tai_adjtime; + tai->caps.gettimex64 = mvpp22_tai_gettimex64; + tai->caps.settime64 = mvpp22_tai_settime64; + + ret = devm_add_action(dev, mvpp22_tai_remove, tai); + if (ret) + return ret; + + tai->ptp_clock = ptp_clock_register(&tai->caps, dev); + if (IS_ERR(tai->ptp_clock)) + return PTR_ERR(tai->ptp_clock); + + priv->tai = tai; + + return 0; +} -- cgit