@@ -532,6 +532,7 @@ struct stmmac_hwtimestamp {
void (*get_systime) (void __iomem *ioaddr, u64 *systime);
void (*get_ptptime)(void __iomem *ioaddr, u64 *ptp_time);
void (*timestamp_interrupt)(struct stmmac_priv *priv);
+ void (*hwtstamp_correct_latency)(struct stmmac_priv *priv);
};
#define stmmac_config_hw_tstamping(__priv, __args...) \
@@ -550,6 +551,8 @@ struct stmmac_hwtimestamp {
stmmac_do_void_callback(__priv, ptp, get_ptptime, __args)
#define stmmac_timestamp_interrupt(__priv, __args...) \
stmmac_do_void_callback(__priv, ptp, timestamp_interrupt, __args)
+#define stmmac_hwtstamp_correct_latency(__priv, __args...) \
+ stmmac_do_void_callback(__priv, ptp, hwtstamp_correct_latency, __args)
struct stmmac_tx_queue;
struct stmmac_rx_queue;
@@ -60,6 +60,48 @@ static void config_sub_second_increment(void __iomem *ioaddr,
*ssinc = data;
}
+static void hwtstamp_correct_latency(struct stmmac_priv *priv)
+{
+ void __iomem *ioaddr = priv->ptpaddr;
+ u32 reg_tsic, reg_tsicsns;
+ u32 reg_tsec, reg_tsecsns;
+ u64 scaled_ns;
+ u32 val;
+
+ /* MAC-internal ingress latency */
+ scaled_ns = readl(ioaddr + PTP_TS_INGR_LAT);
+
+ /* See section 11.7.2.5.3.1 "Ingress Correction" on page 4001 of
+ * i.MX8MP Applications Processor Reference Manual Rev. 1, 06/2021
+ */
+ val = readl(ioaddr + PTP_TCR);
+ if (val & PTP_TCR_TSCTRLSSR)
+ /* nanoseconds field is in decimal format with granularity of 1ns/bit */
+ scaled_ns = ((u64)NSEC_PER_SEC << 16) - scaled_ns;
+ else
+ /* nanoseconds field is in binary format with granularity of ~0.466ns/bit */
+ scaled_ns = ((1ULL << 31) << 16) -
+ DIV_U64_ROUND_CLOSEST(scaled_ns * PSEC_PER_NSEC, 466U);
+
+ reg_tsic = scaled_ns >> 16;
+ reg_tsicsns = scaled_ns & 0xff00;
+
+ /* set bit 31 for 2's compliment */
+ reg_tsic |= BIT(31);
+
+ writel(reg_tsic, ioaddr + PTP_TS_INGR_CORR_NS);
+ writel(reg_tsicsns, ioaddr + PTP_TS_INGR_CORR_SNS);
+
+ /* MAC-internal egress latency */
+ scaled_ns = readl(ioaddr + PTP_TS_EGR_LAT);
+
+ reg_tsec = scaled_ns >> 16;
+ reg_tsecsns = scaled_ns & 0xff00;
+
+ writel(reg_tsec, ioaddr + PTP_TS_EGR_CORR_NS);
+ writel(reg_tsecsns, ioaddr + PTP_TS_EGR_CORR_SNS);
+}
+
static int init_systime(void __iomem *ioaddr, u32 sec, u32 nsec)
{
u32 value;
@@ -221,4 +263,5 @@ const struct stmmac_hwtimestamp stmmac_ptp = {
.get_systime = get_systime,
.get_ptptime = get_ptptime,
.timestamp_interrupt = timestamp_interrupt,
+ .hwtstamp_correct_latency = hwtstamp_correct_latency,
};
@@ -909,6 +909,9 @@ static int stmmac_init_ptp(struct stmmac_priv *priv)
priv->hwts_tx_en = 0;
priv->hwts_rx_en = 0;
+ if (priv->plat->flags & STMMAC_FLAG_HWTSTAMP_CORRECT_LATENCY)
+ stmmac_hwtstamp_correct_latency(priv, priv);
+
return 0;
}
@@ -1094,6 +1097,9 @@ static void stmmac_mac_link_up(struct phylink_config *config,
if (priv->dma_cap.fpesel)
stmmac_fpe_link_state_handle(priv, true);
+
+ if (priv->plat->flags & STMMAC_FLAG_HWTSTAMP_CORRECT_LATENCY)
+ stmmac_hwtstamp_correct_latency(priv, priv);
}
static const struct phylink_mac_ops stmmac_phylink_mac_ops = {
@@ -26,6 +26,12 @@
#define PTP_ACR 0x40 /* Auxiliary Control Reg */
#define PTP_ATNR 0x48 /* Auxiliary Timestamp - Nanoseconds Reg */
#define PTP_ATSR 0x4c /* Auxiliary Timestamp - Seconds Reg */
+#define PTP_TS_INGR_CORR_NS 0x58 /* Ingress timestamp correction nanoseconds */
+#define PTP_TS_EGR_CORR_NS 0x5C /* Egress timestamp correction nanoseconds*/
+#define PTP_TS_INGR_CORR_SNS 0x60 /* Ingress timestamp correction subnanoseconds */
+#define PTP_TS_EGR_CORR_SNS 0x64 /* Egress timestamp correction subnanoseconds */
+#define PTP_TS_INGR_LAT 0x68 /* MAC internal Ingress Latency */
+#define PTP_TS_EGR_LAT 0x6c /* MAC internal Egress Latency */
#define PTP_STNSUR_ADDSUB_SHIFT 31
#define PTP_DIGITAL_ROLLOVER_MODE 0x3B9ACA00 /* 10e9-1 ns */
@@ -218,6 +218,7 @@ struct dwmac4_addrs {
#define STMMAC_FLAG_INT_SNAPSHOT_EN BIT(9)
#define STMMAC_FLAG_RX_CLK_RUNS_IN_LPI BIT(10)
#define STMMAC_FLAG_EN_TX_LPI_CLOCKGATING BIT(11)
+#define STMMAC_FLAG_HWTSTAMP_CORRECT_LATENCY BIT(12)
struct plat_stmmacenet_data {
int bus_id;
The IEEE1588 Standard specifies that the timestamps of Packets must be captured when the PTP message timestamp point (leading edge of first octet after the start of frame delimiter) crosses the boundary between the node and the network. As the MAC latches the timestamp at an internal point, the captured timestamp must be corrected for the additional data transmission latency, as described in the publicly available datasheet [1]. This patch only corrects for the MAC-Internal delay, which can be read out from the MAC_Ingress_Timestamp_Latency register on DWMAC version 5, since the Phy framework currently does not support querying the Phy ingress and egress latency. The Closs Domain Crossing Circuits errors as indicated in [1] are already being accounted in the stmmac_get_tx_hwtstamp() function and are not corrected here. As the Latency varies for different link speeds and MII modes of operation, the correction value needs to be updated on each link state change. As the delay also causes a phase shift in the timestamp counter compared to the rest of the network, this correction will also reduce phase error when generating PPS outputs from the timestamp counter. Since the correction registers may be unavailable on some hardware and no feature bits are documented for dynamically detection of the MAC propagation delay readout, introduce a feature bit to explicitely enable MAC delay Correction in the gluecode driver. [1] i.MX8MP Reference Manual, rev.1 Section 11.7.2.5.3 "Timestamp correction" Signed-off-by: Johannes Zink <j.zink@pengutronix.de> Link: https://lore.kernel.org/r/20230719-stmmac_correct_mac_delay-v2-1-3366f38ee9a6@pengutronix.de --- Changes in v3: - worked in Richard's review findings. Thank your for your review: - don't do the correction unconditionally, since the correction registers are not guaranteed to be available on any hardware - refactored function names to better reflect the functionality - clarified commit message Changes in v2: - fix builds for 32bit, this was found by the kernel build bot Reported-by: kernel test robot <lkp@intel.com> Closes: https://lore.kernel.org/oe-kbuild-all/202307200225.B8rmKQPN-lkp@intel.com/ - while at it also fix an overflow by shifting a u32 constant from macro by 10bits by casting the constant to u64 --- drivers/net/ethernet/stmicro/stmmac/hwif.h | 3 ++ .../net/ethernet/stmicro/stmmac/stmmac_hwtstamp.c | 43 ++++++++++++++++++++++ drivers/net/ethernet/stmicro/stmmac/stmmac_main.c | 6 +++ drivers/net/ethernet/stmicro/stmmac/stmmac_ptp.h | 6 +++ include/linux/stmmac.h | 1 + 5 files changed, 59 insertions(+)