bnxt_en: add unlocked version of bnxt_refclk_read

Serialization of PHC read with FW reset mechanism uses ptp_lock which
also protects timecounter updates. This means we cannot grab it when
called from bnxt_cc_read(). Let's move locking into different function.

Fixes: 6c0828d00f07 ("bnxt_en: replace PTP spinlock with seqlock")
Signed-off-by: Vadim Fedorenko <vadfed@meta.com>
Reviewed-by: Pavan Chebbi <pavan.chebbi@broadcom.com>
Link: https://patch.msgid.link/20241107214917.2980976-1-vadfed@meta.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

diff --git a/drivers/net/ethernet/broadcom/bnxt/bnxt_ptp.c b/drivers/net/ethernet/broadcom/bnxt/bnxt_ptp.c
index f74afda..91e7e08 100644 (file)
--- a/drivers/net/ethernet/broadcom/bnxt/bnxt_ptp.c
+++ b/drivers/net/ethernet/broadcom/bnxt/bnxt_ptp.c
@@ -73,19 +73,15 @@ static int bnxt_ptp_settime(struct ptp_clock_info *ptp_info,
        return 0;
 }
 
-static int bnxt_refclk_read(struct bnxt *bp, struct ptp_system_timestamp *sts,
-                           u64 *ns)
+/* Caller holds ptp_lock */
+static int __bnxt_refclk_read(struct bnxt *bp, struct ptp_system_timestamp *sts,
+                             u64 *ns)
 {
        struct bnxt_ptp_cfg *ptp = bp->ptp_cfg;
        u32 high_before, high_now, low;
-       unsigned long flags;
 
-       /* We have to serialize reg access and FW reset */
-       read_seqlock_excl_irqsave(&ptp->ptp_lock, flags);
-       if (test_bit(BNXT_STATE_IN_FW_RESET, &bp->state)) {
-               read_sequnlock_excl_irqrestore(&ptp->ptp_lock, flags);
+       if (test_bit(BNXT_STATE_IN_FW_RESET, &bp->state))
                return -EIO;
-       }
 
        high_before = readl(bp->bar0 + ptp->refclk_mapped_regs[1]);
        ptp_read_system_prets(sts);
@@ -97,12 +93,25 @@ static int bnxt_refclk_read(struct bnxt *bp, struct ptp_system_timestamp *sts,
                low = readl(bp->bar0 + ptp->refclk_mapped_regs[0]);
                ptp_read_system_postts(sts);
        }
-       read_sequnlock_excl_irqrestore(&ptp->ptp_lock, flags);
        *ns = ((u64)high_now << 32) | low;
 
        return 0;
 }
 
+static int bnxt_refclk_read(struct bnxt *bp, struct ptp_system_timestamp *sts,
+                           u64 *ns)
+{
+       struct bnxt_ptp_cfg *ptp = bp->ptp_cfg;
+       unsigned long flags;
+       int rc;
+
+       /* We have to serialize reg access and FW reset */
+       read_seqlock_excl_irqsave(&ptp->ptp_lock, flags);
+       rc = __bnxt_refclk_read(bp, sts, ns);
+       read_sequnlock_excl_irqrestore(&ptp->ptp_lock, flags);
+       return rc;
+}
+
 static void bnxt_ptp_get_current_time(struct bnxt *bp)
 {
        struct bnxt_ptp_cfg *ptp = bp->ptp_cfg;
@@ -674,7 +683,7 @@ static u64 bnxt_cc_read(const struct cyclecounter *cc)
        struct bnxt_ptp_cfg *ptp = container_of(cc, struct bnxt_ptp_cfg, cc);
        u64 ns = 0;
 
-       bnxt_refclk_read(ptp->bp, NULL, &ns);
+       __bnxt_refclk_read(ptp->bp, NULL, &ns);
        return ns;
 }
 
@@ -936,6 +945,7 @@ static bool bnxt_pps_config_ok(struct bnxt *bp)
 static void bnxt_ptp_timecounter_init(struct bnxt *bp, bool init_tc)
 {
        struct bnxt_ptp_cfg *ptp = bp->ptp_cfg;
+       unsigned long flags;
 
        if (!ptp->ptp_clock) {
                memset(&ptp->cc, 0, sizeof(ptp->cc));
@@ -952,8 +962,11 @@ static void bnxt_ptp_timecounter_init(struct bnxt *bp, bool init_tc)
                }
                ptp->next_overflow_check = jiffies + BNXT_PHC_OVERFLOW_PERIOD;
        }
-       if (init_tc)
+       if (init_tc) {
+               write_seqlock_irqsave(&ptp->ptp_lock, flags);
                timecounter_init(&ptp->tc, &ptp->cc, ktime_to_ns(ktime_get_real()));
+               write_sequnlock_irqrestore(&ptp->ptp_lock, flags);
+       }
 }
 
 /* Caller holds ptp_lock */