realtek: pcs: rtl931x: add some debug prints to RX calibration

Add some debugging aid to the RX calibration, making it easier to spot
eventual issues caused by calibration. While the calibration has been
tested, this happened only on a small set of devices.

Adds rtpcs_931x_sds_rxeq_leq_get_coef() to read back where LEQ
auto-adapt actually settles in rxcal_leq_adapt(), mirroring what
rxcal_fiber_adapt() already does for VTH. Shares the existing
930x gray-to-binary helper since it's pure bit math, not
variant-specific. Promote it to a generic helper instead of
930x-specific.

Link: https://github.com/openwrt/openwrt/pull/24542
Signed-off-by: Jonas Jelonek <jelonek.jonas@gmail.com>

diff --git a/target/linux/realtek/files-6.18/drivers/net/pcs/pcs-rtl-otto.c b/target/linux/realtek/files-6.18/drivers/net/pcs/pcs-rtl-otto.c
index 1114edf967c6a683cbb9100c60e900234dd4d5f1..4f4ff7a2e9a9cdc278a3a413e71288ebfbb6fe1e 100644 (file)
--- a/target/linux/realtek/files-6.18/drivers/net/pcs/pcs-rtl-otto.c
+++ b/target/linux/realtek/files-6.18/drivers/net/pcs/pcs-rtl-otto.c
@@ -365,6 +365,17 @@ static unsigned int rtpcs_sign_mag_encode(int val, unsigned int sign_bit)
        return (val < 0 ? BIT(sign_bit) : 0) | (abs(val) & GENMASK(sign_bit - 1, 0));
 }
 
+static u32 rtpcs_gray_to_binary(u32 gray_code)
+{
+       u32 binary = gray_code;
+
+       gray_code &= 0x1f; /* only lower 5 bits */
+       while (gray_code >>= 1)
+               binary ^= gray_code;
+
+       return binary;
+}
+
 /*
  * Basic helpers
  *
@@ -2150,17 +2161,6 @@ static int rtpcs_930x_sds_rxcal_leq_set_coef(struct rtpcs_serdes *sds, unsigned
        return rtpcs_sds_write_bits(sds, PAGE_ANA_10G, 0x16, 14, 10, leq_gray);
 }
 
-static u32 rtpcs_930x_sds_rxcal_gray_to_binary(u32 gray_code)
-{
-       u32 binary = gray_code;
-
-       gray_code &= 0x1f; /* only lower 5 bits */
-       while (gray_code >>= 1)
-               binary ^= gray_code;
-
-       return binary;
-}
-
 static int rtpcs_930x_sds_rxcal_leq_get_coef(struct rtpcs_serdes *sds)
 {
        int bin, gray, manual, ret;
@@ -2175,7 +2175,7 @@ static int rtpcs_930x_sds_rxcal_leq_get_coef(struct rtpcs_serdes *sds)
        if (gray < 0)
                return gray;
 
-       bin = rtpcs_930x_sds_rxcal_gray_to_binary(gray);
+       bin = rtpcs_gray_to_binary(gray);
 
        manual = rtpcs_sds_read_bits(sds, PAGE_ANA_10G, 0x18, 15, 15);
        if (manual < 0)
@@ -3156,6 +3156,21 @@ static int rtpcs_931x_sds_rxeq_leq_set_coef(struct rtpcs_serdes *sds, unsigned i
        return rtpcs_sds_write_bits(sds, PAGE_ANA_10G, 0xd, 6, 2, gain);
 }
 
+static int rtpcs_931x_sds_rxeq_leq_get_coef(struct rtpcs_serdes *sds)
+{
+       int ret, gray;
+
+       ret = rtpcs_931x_sds_set_debug(sds, 0x1);
+       if (ret < 0)
+               return ret;
+
+       gray = rtpcs_sds_read_bits(sds, PAGE_WDIG, 0x14, 7, 3);
+       if (gray < 0)
+               return gray;
+
+       return rtpcs_gray_to_binary(gray);
+}
+
 static int rtpcs_931x_sds_rxeq_tap_set_value(struct rtpcs_serdes *sds, unsigned int tap_id,
                                             int tap_even, int tap_odd)
 {
@@ -3381,6 +3396,8 @@ static void rtpcs_931x_sds_rx_reset(struct rtpcs_serdes *sds)
  */
 static void rtpcs_931x_sds_rxcal_leq_adapt(struct rtpcs_serdes *sds)
 {
+       dev_dbg(sds->ctrl->dev, "SerDes %u PHY-attached RX calibration...\n", sds->id);
+
        rtpcs_931x_sds_rxeq_leq_set_coef(sds, 0);
        rtpcs_sds_write_bits(sds, PAGE_ANA_10G, 0xd, 1, 0, 0x0);   /* undocumented */
        rtpcs_sds_write_bits(sds, PAGE_ANA_10G, 0xd, 13, 13, 0x0); /* undocumented */
@@ -3392,6 +3409,9 @@ static void rtpcs_931x_sds_rxcal_leq_adapt(struct rtpcs_serdes *sds)
        msleep(10);
        rtpcs_931x_sds_rxeq_leq_set_adapt(sds, true);
        msleep(100);
+
+       dev_dbg(sds->ctrl->dev, "SerDes %u LEQ = %#x\n", sds->id,
+               rtpcs_931x_sds_rxeq_leq_get_coef(sds));
 }
 
 /*
@@ -3415,6 +3435,7 @@ static void rtpcs_931x_sds_rxcal_fiber_adapt(struct rtpcs_serdes *sds)
        unsigned int vth_p = 0, vth_n = 0;
        int i, symerr = -1;
 
+       dev_dbg(dev, "SerDes %u fiber RX calibration...\n", sds->id);
        /* per-port calibration offset in the SDK, kept 0 here */
        rtpcs_sds_write_bits(sds, PAGE_ANA_10G, 0xc, 14, 10, 0x0);
 
@@ -3429,6 +3450,8 @@ static void rtpcs_931x_sds_rxcal_fiber_adapt(struct rtpcs_serdes *sds)
        if (rtpcs_931x_sds_rxeq_vth_get(sds, &vth_p, &vth_n) < 0)
                dev_warn(dev, "SerDes %u failed to read auto-adapted VTH\n", sds->id);
 
+       dev_dbg(dev, "SerDes %u VTH = %#x/%#x\n", sds->id, vth_p, vth_n);
+
        rtpcs_931x_sds_rxeq_tap_set_value(sds, 0, 31, 0);
        rtpcs_931x_sds_rxeq_tap_set_adapt(sds, 0, false);
        rtpcs_931x_sds_rxeq_vth_set_value(sds, vth_p, vth_n);
@@ -3444,8 +3467,14 @@ static void rtpcs_931x_sds_rxcal_fiber_adapt(struct rtpcs_serdes *sds)
                rtpcs_931x_sds_clear_symerr(sds, RTPCS_SDS_MODE_10GBASER);
                msleep(300);
                symerr = rtpcs_931x_sds_fiber_get_symerr(sds, RTPCS_SDS_MODE_10GBASER);
-               if (symerr >= 0 && symerr <= 5)
+
+               dev_dbg(dev, "SerDes %u symErr check %d: 0x%x\n", sds->id, i + 1, symerr);
+
+               if (symerr >= 0 && symerr <= 5) {
+                       dev_dbg(dev, "SerDes %u fiber RX calibration OK (check %d)\n",
+                               sds->id, i + 1);
                        return;
+               }
        }
 
        dev_warn(dev, "SerDes %u fiber RX calibration failed after %d symErr checks\n",