Re: [PATCH net-next v2 01/12] net: stmmac: Get correct timestamp values from XGMAC
From: Jakub Kicinski <hidden>
Date: 2019-08-13 20:57:37
Also in:
linux-arm-kernel, lkml
On Mon, 12 Aug 2019 11:44:00 +0200, Jose Abreu wrote:
TX Timestamp in XGMAC comes from MAC instead of descriptors. Implement this in a new callback. Also, RX Timestamp in XGMAC must be cheked against corruption and we need a barrier to make sure that descriptor fields are read correctly. Changes from v1: - Rework the get timestamp function (David) Signed-off-by: Jose Abreu <redacted>
The barrier sounds like it might be a bug fix, does it occur in he wild?
quoted hunk ↗ jump to hunk
@@ -113,13 +119,11 @@ static int dwxgmac2_get_rx_timestamp_status(void *desc, void *next_desc, unsigned int rdes3 = le32_to_cpu(p->des3); int ret = -EBUSY; - if (likely(rdes3 & XGMAC_RDES3_CDA)) { + if (likely(rdes3 & XGMAC_RDES3_CDA)) ret = dwxgmac2_rx_check_timestamp(next_desc); - if (ret) - return ret; - } - - return ret; + if (!ret) + return 1; + return 0;
nit: return !ret;
} static void dwxgmac2_init_rx_desc(struct dma_desc *p, int disable_rx_ic,