diff options
| author | Vadim Fedorenko <vadfed@meta.com> | 2024-11-03 13:51:07 -0800 |
|---|---|---|
| committer | Jakub Kicinski <kuba@kernel.org> | 2024-11-05 17:33:26 -0800 |
| commit | bb2ef9b92bdf7e2e3b5df9747e6f7dcf51587450 (patch) | |
| tree | 26e0ac48e371ca1e434308d98a959912a6235332 | |
| parent | f72aa1b276281b4e4f75261af8425bc99d903f3e (diff) | |
bnxt_en: cache only 24 bits of hw counter
This hardware can provide only 48 bits of cycle counter. We can leave
only 24 bits in the cache to extend RX timestamps from 32 bits to 48
bits. Lower 8 bits of the cached value will be used to check for
roll-over while extending to full 48 bits.
This change makes cache writes atomic even on 32 bit platforms and we
can simply use READ_ONCE()/WRITE_ONCE() pair and remove spinlock. The
configuration structure will be also reduced by 4 bytes.
Reviewed-by: Michael Chan <michael.chan@broadcom.com>
Signed-off-by: Vadim Fedorenko <vadfed@meta.com>
Link: https://patch.msgid.link/20241103215108.557531-1-vadfed@meta.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
| -rw-r--r-- | drivers/net/ethernet/broadcom/bnxt/bnxt_ptp.c | 8 | ||||
| -rw-r--r-- | drivers/net/ethernet/broadcom/bnxt/bnxt_ptp.h | 18 |
2 files changed, 7 insertions, 19 deletions
diff --git a/drivers/net/ethernet/broadcom/bnxt/bnxt_ptp.c b/drivers/net/ethernet/broadcom/bnxt/bnxt_ptp.c index fa514be87650..ccf0ab304ed9 100644 --- a/drivers/net/ethernet/broadcom/bnxt/bnxt_ptp.c +++ b/drivers/net/ethernet/broadcom/bnxt/bnxt_ptp.c @@ -106,7 +106,7 @@ static void bnxt_ptp_get_current_time(struct bnxt *bp) if (!ptp) return; spin_lock_irqsave(&ptp->ptp_lock, flags); - WRITE_ONCE(ptp->old_time, ptp->current_time); + WRITE_ONCE(ptp->old_time, ptp->current_time >> BNXT_HI_TIMER_SHIFT); bnxt_refclk_read(bp, NULL, &ptp->current_time); spin_unlock_irqrestore(&ptp->ptp_lock, flags); } @@ -174,7 +174,7 @@ void bnxt_ptp_update_current_time(struct bnxt *bp) struct bnxt_ptp_cfg *ptp = bp->ptp_cfg; bnxt_refclk_read(ptp->bp, NULL, &ptp->current_time); - WRITE_ONCE(ptp->old_time, ptp->current_time); + WRITE_ONCE(ptp->old_time, ptp->current_time >> BNXT_HI_TIMER_SHIFT); } static int bnxt_ptp_adjphc(struct bnxt_ptp_cfg *ptp, s64 delta) @@ -813,7 +813,7 @@ int bnxt_get_rx_ts_p5(struct bnxt *bp, u64 *ts, u32 pkt_ts) if (!ptp) return -ENODEV; - BNXT_READ_TIME64(ptp, time, ptp->old_time); + time = (u64)READ_ONCE(ptp->old_time) << BNXT_HI_TIMER_SHIFT; *ts = (time & BNXT_HI_TIMER_MASK) | pkt_ts; if (pkt_ts < (time & BNXT_LO_TIMER_MASK)) *ts += BNXT_LO_TIMER_MASK + 1; @@ -1079,7 +1079,7 @@ int bnxt_ptp_init(struct bnxt *bp, bool phc_cfg) spin_lock_irqsave(&ptp->ptp_lock, flags); bnxt_refclk_read(bp, NULL, &ptp->current_time); - WRITE_ONCE(ptp->old_time, ptp->current_time); + WRITE_ONCE(ptp->old_time, ptp->current_time >> BNXT_HI_TIMER_SHIFT); spin_unlock_irqrestore(&ptp->ptp_lock, flags); ptp_schedule_worker(ptp->ptp_clock, 0); } diff --git a/drivers/net/ethernet/broadcom/bnxt/bnxt_ptp.h b/drivers/net/ethernet/broadcom/bnxt/bnxt_ptp.h index f322466ecad3..3ac5cbc1c5c4 100644 --- a/drivers/net/ethernet/broadcom/bnxt/bnxt_ptp.h +++ b/drivers/net/ethernet/broadcom/bnxt/bnxt_ptp.h @@ -21,6 +21,7 @@ #define BNXT_DEVCLK_FREQ 1000000 #define BNXT_LO_TIMER_MASK 0x0000ffffffffUL #define BNXT_HI_TIMER_MASK 0xffff00000000UL +#define BNXT_HI_TIMER_SHIFT 24 #define BNXT_PTP_DFLT_TX_TMO 1000 /* ms */ #define BNXT_PTP_QTS_TIMEOUT 1000 @@ -106,10 +107,11 @@ struct bnxt_ptp_cfg { /* serialize ts tx request queuing */ spinlock_t ptp_tx_lock; u64 current_time; - u64 old_time; unsigned long next_period; unsigned long next_overflow_check; u32 cmult; + /* cache of upper 24 bits of cyclecoutner. 8 bits are used to check for roll-over */ + u32 old_time; /* a 23b shift cyclecounter will overflow in ~36 mins. Check overflow every 18 mins. */ #define BNXT_PHC_OVERFLOW_PERIOD (18 * 60 * HZ) @@ -145,20 +147,6 @@ struct bnxt_ptp_cfg { struct bnxt_ptp_stats stats; }; -#if BITS_PER_LONG == 32 -#define BNXT_READ_TIME64(ptp, dst, src) \ -do { \ - unsigned long flags; \ - \ - spin_lock_irqsave(&(ptp)->ptp_lock, flags); \ - (dst) = (src); \ - spin_unlock_irqrestore(&(ptp)->ptp_lock, flags); \ -} while (0) -#else -#define BNXT_READ_TIME64(ptp, dst, src) \ - ((dst) = READ_ONCE(src)) -#endif - #define BNXT_PTP_INC_TX_AVAIL(ptp) \ do { \ spin_lock_bh(&(ptp)->ptp_tx_lock); \ |