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ptp: ocp: Improve PCIe delay estimation

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The PCIe bus can be pretty busy during boot and probe function can
see excessive delays. Let's find the minimal value out of several
tests and use it as estimated value.

Signed-off-by: Vadim Fedorenko <vadim.fedorenko@linux.dev>
Link: https://patch.msgid.link/20240905140028.560454-1-vadim.fedorenko@linux.dev
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
This commit is contained in:
Vadim Fedorenko 2024-09-05 14:00:28 +00:00 committed by Jakub Kicinski
parent 9a95eedc81
commit aa05fe67bc
1 changed files with 11 additions and 9 deletions
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20
drivers/ptp/ptp_ocp.c
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@ -1558,22 +1558,24 @@ ptp_ocp_watchdog(struct timer_list *t)
static void
ptp_ocp_estimate_pci_timing(struct ptp_ocp *bp)
{
ktime_t start, end;
ktime_t delay;
ktime_t start, end, delay = U64_MAX;
u32 ctrl;
int i;
ctrl = ioread32(&bp->reg->ctrl);
ctrl = OCP_CTRL_READ_TIME_REQ | OCP_CTRL_ENABLE;
for (i = 0; i < 3; i++) {
ctrl = ioread32(&bp->reg->ctrl);
ctrl = OCP_CTRL_READ_TIME_REQ | OCP_CTRL_ENABLE;
iowrite32(ctrl, &bp->reg->ctrl);
iowrite32(ctrl, &bp->reg->ctrl);
start = ktime_get_ns();
start = ktime_get_raw_ns();
ctrl = ioread32(&bp->reg->ctrl);
ctrl = ioread32(&bp->reg->ctrl);
end = ktime_get_ns();
end = ktime_get_raw_ns();
delay = end - start;
delay = min(delay, end - start);
}
bp->ts_window_adjust = (delay >> 5) * 3;
}