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bnxt_en: optimize gettimex64

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Current implementation of gettimex64() makes at least 3 PCIe reads to
get current PHC time. It takes at least 2.2us to get this value back to
userspace. At the same time there is cached value of upper bits of PHC
available for packet timestamps already. This patch reuses cached value
to speed up reading of PHC time.

Signed-off-by: Vadim Fedorenko <vadfed@meta.com>
Reviewed-by: Michael Chan <michael.chan@broadcom.com>
Reviewed-by: Jacob Keller <jacob.e.keller@intel.com>
Link: https://patch.msgid.link/20241114114820.1411660-1-vadfed@meta.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
This commit is contained in:
Vadim Fedorenko 2024-11-14 03:48:20 -08:00 committed by Jakub Kicinski
parent ed7231f56c
commit c7a21af711
2 changed files with 37 additions and 6 deletions
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32
drivers/net/ethernet/broadcom/bnxt/bnxt_ptp.c
View File

@ -112,6 +112,28 @@ static int bnxt_refclk_read(struct bnxt *bp, struct ptp_system_timestamp *sts,
return rc;
}
static int bnxt_refclk_read_low(struct bnxt *bp, struct ptp_system_timestamp *sts,
u32 *low)
{
struct bnxt_ptp_cfg *ptp = bp->ptp_cfg;
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);
return -EIO;
}
ptp_read_system_prets(sts);
*low = readl(bp->bar0 + ptp->refclk_mapped_regs[0]);
ptp_read_system_postts(sts);
read_sequnlock_excl_irqrestore(&ptp->ptp_lock, flags);
return 0;
}
static void bnxt_ptp_get_current_time(struct bnxt *bp)
{
struct bnxt_ptp_cfg *ptp = bp->ptp_cfg;
@ -163,12 +185,14 @@ static int bnxt_ptp_gettimex(struct ptp_clock_info *ptp_info,
struct bnxt_ptp_cfg *ptp = container_of(ptp_info, struct bnxt_ptp_cfg,
ptp_info);
u64 ns, cycles;
u32 low;
int rc;
rc = bnxt_refclk_read(ptp->bp, sts, &cycles);
rc = bnxt_refclk_read_low(ptp->bp, sts, &low);
if (rc)
return rc;
cycles = bnxt_extend_cycles_32b_to_48b(ptp, low);
ns = bnxt_timecounter_cyc2time(ptp, cycles);
*ts = ns_to_timespec64(ns);
@ -801,15 +825,11 @@ void bnxt_get_tx_ts_p5(struct bnxt *bp, struct sk_buff *skb, u16 prod)
int bnxt_get_rx_ts_p5(struct bnxt *bp, u64 *ts, u32 pkt_ts)
{
struct bnxt_ptp_cfg *ptp = bp->ptp_cfg;
u64 time;
if (!ptp)
return -ENODEV;
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;
*ts = bnxt_extend_cycles_32b_to_48b(ptp, pkt_ts);
return 0;
}

11
drivers/net/ethernet/broadcom/bnxt/bnxt_ptp.h
View File

@ -182,4 +182,15 @@ static inline u64 bnxt_timecounter_cyc2time(struct bnxt_ptp_cfg *ptp, u64 ts)
return ns;
}
static inline u64 bnxt_extend_cycles_32b_to_48b(struct bnxt_ptp_cfg *ptp, u32 ts)
{
u64 time, cycles;
time = (u64)READ_ONCE(ptp->old_time) << BNXT_HI_TIMER_SHIFT;
cycles = (time & BNXT_HI_TIMER_MASK) | ts;
if (ts < (time & BNXT_LO_TIMER_MASK))
cycles += BNXT_LO_TIMER_MASK + 1;
return cycles;
}
#endif