From:   Serge Semin <Sergey.Semin@baikalelectronics.ru>
To:     Giuseppe Cavallaro <peppe.cavallaro@st.com>,
        Alexandre Torgue <alexandre.torgue@foss.st.com>,
        Jose Abreu <joabreu@synopsys.com>,
        "David S. Miller" <davem@davemloft.net>,
        Eric Dumazet <edumazet@google.com>,
        Jakub Kicinski <kuba@kernel.org>,
        Paolo Abeni <pabeni@redhat.com>,
        Maxime Coquelin <mcoquelin.stm32@gmail.com>,
        Russell King <linux@armlinux.org.uk>,
        Andrew Lunn <andrew@lunn.ch>,
        Heiner Kallweit <hkallweit1@gmail.com>
CC:     Serge Semin <Sergey.Semin@baikalelectronics.ru>,
        Serge Semin <fancer.lancer@gmail.com>,
        Alexey Malahov <Alexey.Malahov@baikalelectronics.ru>,
        Pavel Parkhomenko <Pavel.Parkhomenko@baikalelectronics.ru>,
        Christian Marangi <ansuelsmth@gmail.com>,
        Biao Huang <biao.huang@mediatek.com>,
        Yang Yingliang <yangyingliang@huawei.com>,
        <netdev@vger.kernel.org>,
        <linux-stm32@st-md-mailman.stormreply.com>,
        <linux-arm-kernel@lists.infradead.org>,
        <linux-kernel@vger.kernel.org>
Subject: [PATCH net 05/13] net: stmmac: Enable ATDS for chain-mode
Date:   Tue, 14 Mar 2023 01:42:29 +0300
Message-ID: <20230313224237.28757-6-Sergey.Semin@baikalelectronics.ru>
In-Reply-To: <20230313224237.28757-1-Sergey.Semin@baikalelectronics.ru>
References: <20230313224237.28757-1-Sergey.Semin@baikalelectronics.ru>
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Precedence: bulk

It wasn't stated why the Alternate Descriptor Size shouldn't have been
changed for the chained DMA descriptors, while the original commit did
introduce some chain_mode.c modifications. So the ATDS-related change in
commit c24602ef8664 ("stmmac: support extend descriptors") seems
contradicting. Anyway from the DW MAC/GMAC hardware point of view there is
no such limitation - whether the chained descriptors can't be used
together with the extended alternate descriptors. Moreover not setting the
BUS_MODE.ATDS flag will cause the driver malfunction in the framework of
the IPC Full Checksum and Advanced Timestamp feature, since the later
features require the additional 4-7 dwords of the DMA descriptor to set
some flags and a timestamp. So to speak in order to have all these
features working correctly in the chained mode too let's make sure the
ATDS flag is set irrespectively from the DMA descriptors mode.

Fixes: c24602ef8664 ("stmmac: support extend descriptors")
Signed-off-by: Serge Semin <Sergey.Semin@baikalelectronics.ru>
---
 drivers/net/ethernet/stmicro/stmmac/stmmac_main.c | 7 ++-----
 1 file changed, 2 insertions(+), 5 deletions(-)

diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
index 2ed63acaee5b..ee4297a25521 100644
--- a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
+++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
@@ -2907,7 +2907,6 @@ static int stmmac_init_dma_engine(struct stmmac_priv *priv)
 	struct stmmac_rx_queue *rx_q;
 	struct stmmac_tx_queue *tx_q;
 	u32 chan = 0;
-	int atds = 0;
 	int ret = 0;
 
 	if (!priv->plat->dma_cfg || !priv->plat->dma_cfg->pbl) {
@@ -2915,9 +2914,6 @@ static int stmmac_init_dma_engine(struct stmmac_priv *priv)
 		return -EINVAL;
 	}
 
-	if (priv->extend_desc && (priv->mode == STMMAC_RING_MODE))
-		atds = 1;
-
 	ret = stmmac_reset(priv, priv->ioaddr);
 	if (ret) {
 		dev_err(priv->device, "Failed to reset the dma\n");
@@ -2925,7 +2921,8 @@ static int stmmac_init_dma_engine(struct stmmac_priv *priv)
 	}
 
 	/* DMA Configuration */
-	stmmac_dma_init(priv, priv->ioaddr, priv->plat->dma_cfg, atds);
+	stmmac_dma_init(priv, priv->ioaddr, priv->plat->dma_cfg,
+			priv->extend_desc);
 
 	if (priv->plat->axi)
 		stmmac_axi(priv, priv->ioaddr, priv->plat->axi);
-- 
2.39.2