Merge branch 'Sub-ns-increment-fixes-in-Macb-PTP'

Harini Katakam says:

====================
Sub ns increment fixes in Macb PTP

The subns increment register fields are not captured correctly in the
driver. Fix the same and also increase the subns incr resolution.

Sub ns resolution was increased to 24 bits in r1p06f2 version. To my
knowledge, this PTP driver, with its current BD time stamp
implementation, is only useful to that version or above. So, I have
increased the resolution unconditionally. Please let me know if there
is any IP versions incompatible with this - there is no register to
obtain this information from.

Changes from RFC:
None
====================

Signed-off-by: David S. Miller <davem@davemloft.net>

2 files changed, 13 insertions, 3 deletions

diff --git a/drivers/net/ethernet/cadence/macb.h b/drivers/net/ethernet/cadence/macb.h
index 6ff123da6a14..98735584570d 100644
--- a/drivers/net/ethernet/cadence/macb.h
+++ b/drivers/net/ethernet/cadence/macb.h
@@ -496,7 +496,11 @@
 
 /* Bitfields in TISUBN */
 #define GEM_SUBNSINCR_OFFSET                    0
-#define GEM_SUBNSINCR_SIZE                      16
+#define GEM_SUBNSINCRL_OFFSET                   24
+#define GEM_SUBNSINCRL_SIZE                     8
+#define GEM_SUBNSINCRH_OFFSET                   0
+#define GEM_SUBNSINCRH_SIZE                     16
+#define GEM_SUBNSINCR_SIZE                      24
 
 /* Bitfields in TI */
 #define GEM_NSINCR_OFFSET                       0
@@ -834,6 +838,9 @@ struct gem_tx_ts {
 /* limit RX checksum offload to TCP and UDP packets */
 #define GEM_RX_CSUM_CHECKED_MASK                2
 
+/* Scaled PPM fraction */
+#define PPM_FRACTION    16
+
 /* struct macb_tx_skb - data about an skb which is being transmitted
  * @skb: skb currently being transmitted, only set for the last buffer
  *       of the frame
diff --git a/drivers/net/ethernet/cadence/macb_ptp.c b/drivers/net/ethernet/cadence/macb_ptp.c
index 0a8aca8d3634..43a3f0dbf857 100644
--- a/drivers/net/ethernet/cadence/macb_ptp.c
+++ b/drivers/net/ethernet/cadence/macb_ptp.c
@@ -104,7 +104,10 @@ static int gem_tsu_incr_set(struct macb *bp, struct tsu_incr *incr_spec)
          * to take effect.
          */
         spin_lock_irqsave(&bp->tsu_clk_lock, flags);
-        gem_writel(bp, TISUBN, GEM_BF(SUBNSINCR, incr_spec->sub_ns));
+        /* RegBit[15:0] = Subns[23:8]; RegBit[31:24] = Subns[7:0] */
+        gem_writel(bp, TISUBN, GEM_BF(SUBNSINCRL, incr_spec->sub_ns) |
+                   GEM_BF(SUBNSINCRH, (incr_spec->sub_ns >>
+                          GEM_SUBNSINCRL_SIZE)));
         gem_writel(bp, TI, GEM_BF(NSINCR, incr_spec->ns));
         spin_unlock_irqrestore(&bp->tsu_clk_lock, flags);
 
@@ -135,7 +138,7 @@ static int gem_ptp_adjfine(struct ptp_clock_info *ptp, long scaled_ppm)
          * (temp / USEC_PER_SEC) + 0.5
          */
         adj += (USEC_PER_SEC >> 1);
-        adj >>= GEM_SUBNSINCR_SIZE; /* remove fractions */
+        adj >>= PPM_FRACTION; /* remove fractions */
         adj = div_u64(adj, USEC_PER_SEC);
         adj = neg_adj ? (word - adj) : (word + adj);