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

From: Ilya Lipnitskiy
Date: Thu Apr 22 2021 - 00:11:08 EST


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@xxxxxxxxx>
---
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