lists.openwall.net   lists  /  announce  owl-users  owl-dev  john-users  john-dev  passwdqc-users  yescrypt  popa3d-users  /  oss-security  kernel-hardening  musl  sabotage  tlsify  passwords  /  crypt-dev  xvendor  /  Bugtraq  Full-Disclosure  linux-kernel  linux-netdev  linux-ext4  PHC 
Open Source and information security mailing list archives
 
Hash Suite: Windows password security audit tool. GUI, reports in PDF.
[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Date:	Thu, 1 Nov 2012 17:41:32 +0800
From:	Bob Liu <lliubbo@...il.com>
To:	Richard Cochran <richardcochran@...il.com>
Cc:	netdev@...r.kernel.org, device-drivers-devel@...ckfin.uclinux.org,
	uclinux-dist-devel@...ckfin.uclinux.org,
	David Miller <davem@...emloft.net>,
	Jacob Keller <jacob.e.keller@...el.com>,
	Jeff Kirsher <jeffrey.t.kirsher@...el.com>,
	John Ronciak <john.ronciak@...el.com>,
	John Stultz <john.stultz@...aro.org>,
	Mike Frysinger <vapier@...too.org>,
	Sonic Zhang <sonic.zhang@...log.com>
Subject: Re: [PATCH V2 net-next 2/4] bfin_mac: replace sys time stamps with
 raw ones instead.

On Thu, Nov 1, 2012 at 12:27 AM, Richard Cochran
<richardcochran@...il.com> wrote:
> This patch replaces the sys time stamps and timecompare code with simple
> raw hardware time stamps in nanosecond resolution. The only tricky bit is
> to find a PTP Hardware Clock period slower than the input clock period
> and a power of two.
>
> Compile tested only.
>
> Signed-off-by: Richard Cochran <richardcochran@...il.com>

Tested-by: Bob Liu <lliubbo@...il.com>

> ---
>  drivers/net/ethernet/adi/bfin_mac.c |   91 ++++++++++-------------------------
>  drivers/net/ethernet/adi/bfin_mac.h |    7 +--
>  2 files changed, 28 insertions(+), 70 deletions(-)
>
> diff --git a/drivers/net/ethernet/adi/bfin_mac.c b/drivers/net/ethernet/adi/bfin_mac.c
> index 2349abb..885fa80 100644
> --- a/drivers/net/ethernet/adi/bfin_mac.c
> +++ b/drivers/net/ethernet/adi/bfin_mac.c
> @@ -555,7 +555,7 @@ static int bfin_mac_ethtool_get_ts_info(struct net_device *dev,
>         info->so_timestamping =
>                 SOF_TIMESTAMPING_TX_HARDWARE |
>                 SOF_TIMESTAMPING_RX_HARDWARE |
> -               SOF_TIMESTAMPING_SYS_HARDWARE;
> +               SOF_TIMESTAMPING_RAW_HARDWARE;
>         info->phc_index = -1;
>         info->tx_types =
>                 (1 << HWTSTAMP_TX_OFF) |
> @@ -653,6 +653,20 @@ static int bfin_mac_set_mac_address(struct net_device *dev, void *p)
>  #ifdef CONFIG_BFIN_MAC_USE_HWSTAMP
>  #define bfin_mac_hwtstamp_is_none(cfg) ((cfg) == HWTSTAMP_FILTER_NONE)
>
> +static u32 bfin_select_phc_clock(u32 input_clk, unsigned int *shift_result)
> +{
> +       u32 ipn = 1000000000UL / input_clk;
> +       u32 ppn = 1;
> +       unsigned int shift = 0;
> +
> +       while (ppn <= ipn) {
> +               ppn <<= 1;
> +               shift++;
> +       }
> +       *shift_result = shift;
> +       return 1000000000UL / ppn;
> +}
> +
>  static int bfin_mac_hwtstamp_ioctl(struct net_device *netdev,
>                 struct ifreq *ifr, int cmd)
>  {
> @@ -802,19 +816,7 @@ static int bfin_mac_hwtstamp_ioctl(struct net_device *netdev,
>                 bfin_read_EMAC_PTP_TXSNAPLO();
>                 bfin_read_EMAC_PTP_TXSNAPHI();
>
> -               /*
> -                * Set registers so that rollover occurs soon to test this.
> -                */
> -               bfin_write_EMAC_PTP_TIMELO(0x00000000);
> -               bfin_write_EMAC_PTP_TIMEHI(0xFF800000);
> -
>                 SSYNC();
> -
> -               lp->compare.last_update = 0;
> -               timecounter_init(&lp->clock,
> -                               &lp->cycles,
> -                               ktime_to_ns(ktime_get_real()));
> -               timecompare_update(&lp->compare, 0);
>         }
>
>         lp->stamp_cfg = config;
> @@ -822,15 +824,6 @@ static int bfin_mac_hwtstamp_ioctl(struct net_device *netdev,
>                 -EFAULT : 0;
>  }
>
> -static void bfin_dump_hwtamp(char *s, ktime_t *hw, ktime_t *ts, struct timecompare *cmp)
> -{
> -       ktime_t sys = ktime_get_real();
> -
> -       pr_debug("%s %s hardware:%d,%d transform system:%d,%d system:%d,%d, cmp:%lld, %lld\n",
> -                       __func__, s, hw->tv.sec, hw->tv.nsec, ts->tv.sec, ts->tv.nsec, sys.tv.sec,
> -                       sys.tv.nsec, cmp->offset, cmp->skew);
> -}
> -
>  static void bfin_tx_hwtstamp(struct net_device *netdev, struct sk_buff *skb)
>  {
>         struct bfin_mac_local *lp = netdev_priv(netdev);
> @@ -861,15 +854,9 @@ static void bfin_tx_hwtstamp(struct net_device *netdev, struct sk_buff *skb)
>                         regval = bfin_read_EMAC_PTP_TXSNAPLO();
>                         regval |= (u64)bfin_read_EMAC_PTP_TXSNAPHI() << 32;
>                         memset(&shhwtstamps, 0, sizeof(shhwtstamps));
> -                       ns = timecounter_cyc2time(&lp->clock,
> -                                       regval);
> -                       timecompare_update(&lp->compare, ns);
> +                       ns = regval << lp->shift;
>                         shhwtstamps.hwtstamp = ns_to_ktime(ns);
> -                       shhwtstamps.syststamp =
> -                               timecompare_transform(&lp->compare, ns);
>                         skb_tstamp_tx(skb, &shhwtstamps);
> -
> -                       bfin_dump_hwtamp("TX", &shhwtstamps.hwtstamp, &shhwtstamps.syststamp, &lp->compare);
>                 }
>         }
>  }
> @@ -892,51 +879,25 @@ static void bfin_rx_hwtstamp(struct net_device *netdev, struct sk_buff *skb)
>
>         regval = bfin_read_EMAC_PTP_RXSNAPLO();
>         regval |= (u64)bfin_read_EMAC_PTP_RXSNAPHI() << 32;
> -       ns = timecounter_cyc2time(&lp->clock, regval);
> -       timecompare_update(&lp->compare, ns);
> +       ns = regval << lp->shift;
>         memset(shhwtstamps, 0, sizeof(*shhwtstamps));
>         shhwtstamps->hwtstamp = ns_to_ktime(ns);
> -       shhwtstamps->syststamp = timecompare_transform(&lp->compare, ns);
> -
> -       bfin_dump_hwtamp("RX", &shhwtstamps->hwtstamp, &shhwtstamps->syststamp, &lp->compare);
> -}
> -
> -/*
> - * bfin_read_clock - read raw cycle counter (to be used by time counter)
> - */
> -static cycle_t bfin_read_clock(const struct cyclecounter *tc)
> -{
> -       u64 stamp;
> -
> -       stamp =  bfin_read_EMAC_PTP_TIMELO();
> -       stamp |= (u64)bfin_read_EMAC_PTP_TIMEHI() << 32ULL;
> -
> -       return stamp;
>  }
>
> -#define PTP_CLK 25000000
> -
>  static void bfin_mac_hwtstamp_init(struct net_device *netdev)
>  {
>         struct bfin_mac_local *lp = netdev_priv(netdev);
> -       u64 append;
> +       u64 addend;
> +       u32 input_clk, phc_clk;
>
>         /* Initialize hardware timer */
> -       append = PTP_CLK * (1ULL << 32);
> -       do_div(append, get_sclk());
> -       bfin_write_EMAC_PTP_ADDEND((u32)append);
> -
> -       memset(&lp->cycles, 0, sizeof(lp->cycles));
> -       lp->cycles.read = bfin_read_clock;
> -       lp->cycles.mask = CLOCKSOURCE_MASK(64);
> -       lp->cycles.mult = 1000000000 / PTP_CLK;
> -       lp->cycles.shift = 0;
> -
> -       /* Synchronize our NIC clock against system wall clock */
> -       memset(&lp->compare, 0, sizeof(lp->compare));
> -       lp->compare.source = &lp->clock;
> -       lp->compare.target = ktime_get_real;
> -       lp->compare.num_samples = 10;
> +       input_clk = get_sclk();
> +       phc_clk = bfin_select_phc_clock(input_clk, &lp->shift);
> +       addend = phc_clk * (1ULL << 32);
> +       do_div(addend, input_clk);
> +       bfin_write_EMAC_PTP_ADDEND((u32)addend);
> +
> +       lp->addend = addend;
>
>         /* Initialize hwstamp config */
>         lp->stamp_cfg.rx_filter = HWTSTAMP_FILTER_NONE;
> diff --git a/drivers/net/ethernet/adi/bfin_mac.h b/drivers/net/ethernet/adi/bfin_mac.h
> index 960905c..57f042c 100644
> --- a/drivers/net/ethernet/adi/bfin_mac.h
> +++ b/drivers/net/ethernet/adi/bfin_mac.h
> @@ -11,8 +11,6 @@
>  #define _BFIN_MAC_H_
>
>  #include <linux/net_tstamp.h>
> -#include <linux/clocksource.h>
> -#include <linux/timecompare.h>
>  #include <linux/timer.h>
>  #include <linux/etherdevice.h>
>  #include <linux/bfin_mac.h>
> @@ -94,9 +92,8 @@ struct bfin_mac_local {
>         struct mii_bus *mii_bus;
>
>  #if defined(CONFIG_BFIN_MAC_USE_HWSTAMP)
> -       struct cyclecounter cycles;
> -       struct timecounter clock;
> -       struct timecompare compare;
> +       u32 addend;
> +       unsigned int shift;
>         struct hwtstamp_config stamp_cfg;
>  #endif
>  };
> --
> 1.7.2.5
>



-- 
Regards,
--Bob
--
To unsubscribe from this list: send the line "unsubscribe netdev" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html

Powered by blists - more mailing lists