netdev - [PATCH net-next 14/14] net: ethernet: mtk_eth_soc: use iopoll.h macro for DMA init

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Date:   Wed, 21 Apr 2021 21:09:14 -0700
From:   Ilya Lipnitskiy <ilya.lipnitskiy@...il.com>
To:     Felix Fietkau <nbd@....name>, John Crispin <john@...ozen.org>,
        Sean Wang <sean.wang@...iatek.com>,
        Mark Lee <Mark-MC.Lee@...iatek.com>,
        "David S. Miller" <davem@...emloft.net>,
        Jakub Kicinski <kuba@...nel.org>,
        Matthias Brugger <matthias.bgg@...il.com>,
        netdev@...r.kernel.org, linux-kernel@...r.kernel.org,
        linux-arm-kernel@...ts.infradead.org,
        linux-mediatek@...ts.infradead.org
Cc:     Ilya Lipnitskiy <ilya.lipnitskiy@...il.com>
Subject: [PATCH net-next 14/14] net: ethernet: mtk_eth_soc: use iopoll.h macro for DMA init

Replace a tight busy-wait loop without a pause with a standard
readx_poll_timeout_atomic routine with a 5 us poll period.

Tested by booting a MT7621 device to ensure the driver initializes
properly.

Signed-off-by: Ilya Lipnitskiy <ilya.lipnitskiy@...il.com>
---
 drivers/net/ethernet/mediatek/mtk_eth_soc.c | 29 +++++++++------------
 drivers/net/ethernet/mediatek/mtk_eth_soc.h |  2 +-
 2 files changed, 14 insertions(+), 17 deletions(-)

diff --git a/drivers/net/ethernet/mediatek/mtk_eth_soc.c b/drivers/net/ethernet/mediatek/mtk_eth_soc.c
index 8c863322587e..720d73d0c007 100644
--- a/drivers/net/ethernet/mediatek/mtk_eth_soc.c
+++ b/drivers/net/ethernet/mediatek/mtk_eth_soc.c
@@ -2037,25 +2037,22 @@ static int mtk_set_features(struct net_device *dev, netdev_features_t features)
 /* wait for DMA to finish whatever it is doing before we start using it again */
 static int mtk_dma_busy_wait(struct mtk_eth *eth)
 {
-	unsigned long t_start = jiffies;
+	u32 val;
+	int ret;
+	unsigned int reg;
 
-	while (1) {
-		if (MTK_HAS_CAPS(eth->soc->caps, MTK_QDMA)) {
-			if (!(mtk_r32(eth, MTK_QDMA_GLO_CFG) &
-			      (MTK_RX_DMA_BUSY | MTK_TX_DMA_BUSY)))
-				return 0;
-		} else {
-			if (!(mtk_r32(eth, MTK_PDMA_GLO_CFG) &
-			      (MTK_RX_DMA_BUSY | MTK_TX_DMA_BUSY)))
-				return 0;
-		}
+	if (MTK_HAS_CAPS(eth->soc->caps, MTK_QDMA))
+		reg = MTK_QDMA_GLO_CFG;
+	else
+		reg = MTK_PDMA_GLO_CFG;
 
-		if (time_after(jiffies, t_start + MTK_DMA_BUSY_TIMEOUT))
-			break;
-	}
+	ret = readx_poll_timeout_atomic(__raw_readl, eth->base + reg, val,
+					!(val & (MTK_RX_DMA_BUSY | MTK_TX_DMA_BUSY)),
+					5, MTK_DMA_BUSY_TIMEOUT_US);
+	if (ret)
+		dev_err(eth->dev, "DMA init timeout\n");
 
-	dev_err(eth->dev, "DMA init timeout\n");
-	return -1;
+	return ret;
 }
 
 static int mtk_dma_init(struct mtk_eth *eth)
diff --git a/drivers/net/ethernet/mediatek/mtk_eth_soc.h b/drivers/net/ethernet/mediatek/mtk_eth_soc.h
index 214da569e869..2e4356ccf778 100644
--- a/drivers/net/ethernet/mediatek/mtk_eth_soc.h
+++ b/drivers/net/ethernet/mediatek/mtk_eth_soc.h
@@ -214,7 +214,7 @@
 #define MTK_TX_DMA_BUSY		BIT(1)
 #define MTK_RX_DMA_EN		BIT(2)
 #define MTK_TX_DMA_EN		BIT(0)
-#define MTK_DMA_BUSY_TIMEOUT	HZ
+#define MTK_DMA_BUSY_TIMEOUT_US	1000000
 
 /* QDMA Reset Index Register */
 #define MTK_QDMA_RST_IDX	0x1A08
-- 
2.31.1