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net: fec: ptp: Use hardware algorithm to adjust PTP counter. 

The FEC IP supports hardware adjustment for ptp timer. Refer to the description of
ENET_ATCOR and ENET_ATINC registers in the spec about the hardware adjustment. This
patch uses hardware support to adjust the ptp offset and frequency on the slave side.

Signed-off-by: Luwei Zhou <b45643@freescale.com>
Signed-off-by: Frank Li <Frank.Li@freescale.com>
Signed-off-by: Fugang Duan <b38611@freescale.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Luwei Zhou 2014-10-10 13:15:29 +08:00 committed by David S. Miller
parent f28460b229
commit 89bddcda7e
2 changed files with 56 additions and 12 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

3
drivers/net/ethernet/freescale/fec.h
View File

@ -484,6 +484,9 @@ struct fec_enet_private {
unsigned int itr_clk_rate;
u32 rx_copybreak;
/* ptp clock period in ns*/
unsigned int ptp_inc;
};
void fec_ptp_init(struct platform_device *pdev);

65
drivers/net/ethernet/freescale/fec_ptp.c
View File

@ -145,32 +145,59 @@ void fec_ptp_start_cyclecounter(struct net_device *ndev)
*/
static int fec_ptp_adjfreq(struct ptp_clock_info *ptp, s32 ppb)
{
u64 diff;
unsigned long flags;
int neg_adj = 0;
u32 mult = FEC_CC_MULT;
u32 i, tmp;
u32 corr_inc, corr_period;
u32 corr_ns;
u64 lhs, rhs;
struct fec_enet_private *fep =
container_of(ptp, struct fec_enet_private, ptp_caps);
if (ppb == 0)
return 0;
if (ppb < 0) {
ppb = -ppb;
neg_adj = 1;
}
diff = mult;
diff *= ppb;
diff = div_u64(diff, 1000000000ULL);
/* In theory, corr_inc/corr_period = ppb/NSEC_PER_SEC;
* Try to find the corr_inc between 1 to fep->ptp_inc to
* meet adjustment requirement.
*/
lhs = NSEC_PER_SEC;
rhs = (u64)ppb * (u64)fep->ptp_inc;
for (i = 1; i <= fep->ptp_inc; i++) {
if (lhs >= rhs) {
corr_inc = i;
corr_period = div_u64(lhs, rhs);
break;
}
lhs += NSEC_PER_SEC;
}
/* Not found? Set it to high value - double speed
* correct in every clock step.
*/
if (i > fep->ptp_inc) {
corr_inc = fep->ptp_inc;
corr_period = 1;
}
if (neg_adj)
corr_ns = fep->ptp_inc - corr_inc;
else
corr_ns = fep->ptp_inc + corr_inc;
spin_lock_irqsave(&fep->tmreg_lock, flags);
/*
* dummy read to set cycle_last in tc to now.
* So use adjusted mult to calculate when next call
* timercounter_read.
*/
timecounter_read(&fep->tc);
fep->cc.mult = neg_adj ? mult - diff : mult + diff;
tmp = readl(fep->hwp + FEC_ATIME_INC) & FEC_T_INC_MASK;
tmp |= corr_ns << FEC_T_INC_CORR_OFFSET;
writel(tmp, fep->hwp + FEC_ATIME_INC);
writel(corr_period, fep->hwp + FEC_ATIME_CORR);
/* dummy read to update the timer. */
timecounter_read(&fep->tc);
spin_unlock_irqrestore(&fep->tmreg_lock, flags);
@ -190,12 +217,19 @@ static int fec_ptp_adjtime(struct ptp_clock_info *ptp, s64 delta)
container_of(ptp, struct fec_enet_private, ptp_caps);
unsigned long flags;
u64 now;
u32 counter;
spin_lock_irqsave(&fep->tmreg_lock, flags);
now = timecounter_read(&fep->tc);
now += delta;
/* Get the timer value based on adjusted timestamp.
* Update the counter with the masked value.
*/
counter = now & fep->cc.mask;
writel(counter, fep->hwp + FEC_ATIME);
/* reset the timecounter */
timecounter_init(&fep->tc, &fep->cc, now);
@ -246,6 +280,7 @@ static int fec_ptp_settime(struct ptp_clock_info *ptp,
u64 ns;
unsigned long flags;
u32 counter;
mutex_lock(&fep->ptp_clk_mutex);
/* Check the ptp clock */
@ -256,8 +291,13 @@ static int fec_ptp_settime(struct ptp_clock_info *ptp,
ns = ts->tv_sec * 1000000000ULL;
ns += ts->tv_nsec;
/* Get the timer value based on timestamp.
* Update the counter with the masked value.
*/
counter = ns & fep->cc.mask;
spin_lock_irqsave(&fep->tmreg_lock, flags);
writel(counter, fep->hwp + FEC_ATIME);
timecounter_init(&fep->tc, &fep->cc, ns);
spin_unlock_irqrestore(&fep->tmreg_lock, flags);
mutex_unlock(&fep->ptp_clk_mutex);
@ -396,6 +436,7 @@ void fec_ptp_init(struct platform_device *pdev)
fep->ptp_caps.enable = fec_ptp_enable;
fep->cycle_speed = clk_get_rate(fep->clk_ptp);
fep->ptp_inc = NSEC_PER_SEC / fep->cycle_speed;
spin_lock_init(&fep->tmreg_lock);