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Message-ID: <CAA_GA1dc1ivxC8W1-2P=bMRQebFJE3w1V5SCmsuVE0dbtD=KUw@mail.gmail.com>
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
--
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