[PATCH AUTOSEL 4.14 14/27] cxgb4: fix large delays in PTP synchronization

From: Sasha Levin
Date: Thu Apr 30 2020 - 10:00:19 EST


From: Rahul Lakkireddy <rahul.lakkireddy@xxxxxxxxxxx>

[ Upstream commit bd019427bf3623ee3c7d2845cf921bbf4c14846c ]

Fetching PTP sync information from mailbox is slow and can take
up to 10 milliseconds. Reduce this unnecessary delay by directly
reading the information from the corresponding registers.

Fixes: 9c33e4208bce ("cxgb4: Add PTP Hardware Clock (PHC) support")
Signed-off-by: Manoj Malviya <manojmalviya@xxxxxxxxxxx>
Signed-off-by: Rahul Lakkireddy <rahul.lakkireddy@xxxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
.../net/ethernet/chelsio/cxgb4/cxgb4_ptp.c | 27 +++++--------------
drivers/net/ethernet/chelsio/cxgb4/t4_regs.h | 3 +++
2 files changed, 9 insertions(+), 21 deletions(-)

diff --git a/drivers/net/ethernet/chelsio/cxgb4/cxgb4_ptp.c b/drivers/net/ethernet/chelsio/cxgb4/cxgb4_ptp.c
index 758f2b8363282..ff7e58a8c90fb 100644
--- a/drivers/net/ethernet/chelsio/cxgb4/cxgb4_ptp.c
+++ b/drivers/net/ethernet/chelsio/cxgb4/cxgb4_ptp.c
@@ -311,32 +311,17 @@ static int cxgb4_ptp_adjtime(struct ptp_clock_info *ptp, s64 delta)
*/
static int cxgb4_ptp_gettime(struct ptp_clock_info *ptp, struct timespec64 *ts)
{
- struct adapter *adapter = (struct adapter *)container_of(ptp,
- struct adapter, ptp_clock_info);
- struct fw_ptp_cmd c;
+ struct adapter *adapter = container_of(ptp, struct adapter,
+ ptp_clock_info);
u64 ns;
- int err;
-
- memset(&c, 0, sizeof(c));
- c.op_to_portid = cpu_to_be32(FW_CMD_OP_V(FW_PTP_CMD) |
- FW_CMD_REQUEST_F |
- FW_CMD_READ_F |
- FW_PTP_CMD_PORTID_V(0));
- c.retval_len16 = cpu_to_be32(FW_CMD_LEN16_V(sizeof(c) / 16));
- c.u.ts.sc = FW_PTP_SC_GET_TIME;

- err = t4_wr_mbox(adapter, adapter->mbox, &c, sizeof(c), &c);
- if (err < 0) {
- dev_err(adapter->pdev_dev,
- "PTP: %s error %d\n", __func__, -err);
- return err;
- }
+ ns = t4_read_reg(adapter, T5_PORT_REG(0, MAC_PORT_PTP_SUM_LO_A));
+ ns |= (u64)t4_read_reg(adapter,
+ T5_PORT_REG(0, MAC_PORT_PTP_SUM_HI_A)) << 32;

/* convert to timespec*/
- ns = be64_to_cpu(c.u.ts.tm);
*ts = ns_to_timespec64(ns);
-
- return err;
+ return 0;
}

/**
diff --git a/drivers/net/ethernet/chelsio/cxgb4/t4_regs.h b/drivers/net/ethernet/chelsio/cxgb4/t4_regs.h
index dac90837842bf..d3df6962cf433 100644
--- a/drivers/net/ethernet/chelsio/cxgb4/t4_regs.h
+++ b/drivers/net/ethernet/chelsio/cxgb4/t4_regs.h
@@ -1810,6 +1810,9 @@

#define MAC_PORT_CFG2_A 0x818

+#define MAC_PORT_PTP_SUM_LO_A 0x990
+#define MAC_PORT_PTP_SUM_HI_A 0x994
+
#define MPS_CMN_CTL_A 0x9000

#define COUNTPAUSEMCRX_S 5
--
2.20.1