From 73fa4597bdc035437fbcd84d6be32bd39f1f2149 Mon Sep 17 00:00:00 2001 From: Alexis Lothore Date: Wed, 23 Apr 2025 09:12:09 +0200 Subject: [PATCH 1/2] net: stmmac: fix dwmac1000 ptp timestamp status offset MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit When a PTP interrupt occurs, the driver accesses the wrong offset to learn about the number of available snapshots in the FIFO for dwmac1000: it should be accessing bits 29..25, while it is currently reading bits 19..16 (those are bits about the auxiliary triggers which have generated the timestamps). As a consequence, it does not compute correctly the number of available snapshots, and so possibly do not generate the corresponding clock events if the bogus value ends up being 0. Fix clock events generation by reading the correct bits in the timestamp register for dwmac1000. Fixes: 477c3e1f6363 ("net: stmmac: Introduce dwmac1000 timestamping operations") Signed-off-by: Alexis Lothoré Reviewed-by: Maxime Chevallier Link: https://patch.msgid.link/20250423-stmmac_ts-v2-1-e2cf2bbd61b1@bootlin.com Signed-off-by: Paolo Abeni --- drivers/net/ethernet/stmicro/stmmac/dwmac1000.h | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/drivers/net/ethernet/stmicro/stmmac/dwmac1000.h b/drivers/net/ethernet/stmicro/stmmac/dwmac1000.h index 967a16212faf..0c011a47d5a3 100644 --- a/drivers/net/ethernet/stmicro/stmmac/dwmac1000.h +++ b/drivers/net/ethernet/stmicro/stmmac/dwmac1000.h @@ -320,8 +320,8 @@ enum rtc_control { /* PTP and timestamping registers */ -#define GMAC3_X_ATSNS GENMASK(19, 16) -#define GMAC3_X_ATSNS_SHIFT 16 +#define GMAC3_X_ATSNS GENMASK(29, 25) +#define GMAC3_X_ATSNS_SHIFT 25 #define GMAC_PTP_TCR_ATSFC BIT(24) #define GMAC_PTP_TCR_ATSEN0 BIT(25) From 7b7491372f8ec2d8c08da18e5d629e55f41dda89 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Alexis=20Lothor=C3=A9?= Date: Wed, 23 Apr 2025 09:12:10 +0200 Subject: [PATCH 2/2] net: stmmac: fix multiplication overflow when reading timestamp MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit The current way of reading a timestamp snapshot in stmmac can lead to integer overflow, as the computation is done on 32 bits. The issue has been observed on a dwmac-socfpga platform returning chaotic timestamp values due to this overflow. The corresponding multiplication is done with a MUL instruction, which returns 32 bit values. Explicitly casting the value to 64 bits replaced the MUL with a UMLAL, which computes and returns the result on 64 bits, and so returns correctly the timestamps. Prevent this overflow by explicitly casting the intermediate value to u64 to make sure that the whole computation is made on u64. While at it, apply the same cast on the other dwmac variant (GMAC4) method for snapshot retrieval. Fixes: 477c3e1f6363 ("net: stmmac: Introduce dwmac1000 timestamping operations") Signed-off-by: Alexis Lothoré Reviewed-by: Maxime Chevallier Link: https://patch.msgid.link/20250423-stmmac_ts-v2-2-e2cf2bbd61b1@bootlin.com Signed-off-by: Paolo Abeni --- drivers/net/ethernet/stmicro/stmmac/dwmac1000_core.c | 2 +- drivers/net/ethernet/stmicro/stmmac/stmmac_hwtstamp.c | 2 +- 2 files changed, 2 insertions(+), 2 deletions(-) diff --git a/drivers/net/ethernet/stmicro/stmmac/dwmac1000_core.c b/drivers/net/ethernet/stmicro/stmmac/dwmac1000_core.c index a8b901cdf5cb..56b76aaa58f0 100644 --- a/drivers/net/ethernet/stmicro/stmmac/dwmac1000_core.c +++ b/drivers/net/ethernet/stmicro/stmmac/dwmac1000_core.c @@ -553,7 +553,7 @@ void dwmac1000_get_ptptime(void __iomem *ptpaddr, u64 *ptp_time) u64 ns; ns = readl(ptpaddr + GMAC_PTP_ATNR); - ns += readl(ptpaddr + GMAC_PTP_ATSR) * NSEC_PER_SEC; + ns += (u64)readl(ptpaddr + GMAC_PTP_ATSR) * NSEC_PER_SEC; *ptp_time = ns; } diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_hwtstamp.c b/drivers/net/ethernet/stmicro/stmmac/stmmac_hwtstamp.c index 0f59aa982604..e2840fa241f2 100644 --- a/drivers/net/ethernet/stmicro/stmmac/stmmac_hwtstamp.c +++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_hwtstamp.c @@ -222,7 +222,7 @@ static void get_ptptime(void __iomem *ptpaddr, u64 *ptp_time) u64 ns; ns = readl(ptpaddr + PTP_ATNR); - ns += readl(ptpaddr + PTP_ATSR) * NSEC_PER_SEC; + ns += (u64)readl(ptpaddr + PTP_ATSR) * NSEC_PER_SEC; *ptp_time = ns; }