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From: Sascha Hauer <s.hauer@pengutronix.de>
To: Barebox List <barebox@lists.infradead.org>
Subject: [PATCH 02/23] net: davinci-emac: Add timeout to polling loop
Date: Fri, 14 Dec 2018 15:17:09 +0100	[thread overview]
Message-ID: <20181214141730.26181-3-s.hauer@pengutronix.de> (raw)
In-Reply-To: <20181214141730.26181-1-s.hauer@pengutronix.de>

Do not poll forever when the hardware does not behave like we want to.

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
---
 drivers/net/davinci_emac.c | 47 ++++++++++++++++++++++++++++++--------
 1 file changed, 38 insertions(+), 9 deletions(-)

diff --git a/drivers/net/davinci_emac.c b/drivers/net/davinci_emac.c
index 2f6091d155..bda62214ef 100644
--- a/drivers/net/davinci_emac.c
+++ b/drivers/net/davinci_emac.c
@@ -105,13 +105,40 @@ static void davinci_eth_mdio_enable(struct davinci_emac_priv *priv)
 	while (readl(priv->adap_mdio + EMAC_MDIO_CONTROL) & MDIO_CONTROL_IDLE);
 }
 
+/* wait until hardware is ready for another user access */
+static int wait_for_user_access(struct davinci_emac_priv *priv, uint32_t *val)
+{
+	u32 tmp;
+	uint64_t start = get_time_ns();
+
+	do {
+		tmp = readl(priv->adap_mdio + EMAC_MDIO_USERACCESS0);
+
+		if (!(tmp & MDIO_USERACCESS0_GO))
+			break;
+
+		if (is_timeout(start, 100 * MSECOND)) {
+			dev_err(priv->dev, "timeout waiting for user access\n");
+			return -ETIMEDOUT;
+		}
+	} while (1);
+
+	if (val)
+		*val = tmp;
+
+	return 0;
+}
+
+
 static int davinci_miibus_read(struct mii_bus *bus, int addr, int reg)
 {
 	struct davinci_emac_priv *priv = bus->priv;
 	uint16_t value;
-	int tmp;
+	int tmp, ret;
 
-	while (readl(priv->adap_mdio + EMAC_MDIO_USERACCESS0) & MDIO_USERACCESS0_GO);
+	ret = wait_for_user_access(priv, NULL);
+	if (ret)
+		return ret;
 
 	writel(MDIO_USERACCESS0_GO |
 		MDIO_USERACCESS0_WRITE_READ |
@@ -119,8 +146,9 @@ static int davinci_miibus_read(struct mii_bus *bus, int addr, int reg)
 		((addr & 0x1f) << 16),
 		priv->adap_mdio + EMAC_MDIO_USERACCESS0);
 
-	/* Wait for command to complete */
-	while ((tmp = readl(priv->adap_mdio + EMAC_MDIO_USERACCESS0)) & MDIO_USERACCESS0_GO);
+	ret = wait_for_user_access(priv, &tmp);
+	if (ret)
+		return ret;
 
 	if (tmp & MDIO_USERACCESS0_ACK) {
 		value = tmp & 0xffff;
@@ -135,7 +163,11 @@ static int davinci_miibus_read(struct mii_bus *bus, int addr, int reg)
 static int davinci_miibus_write(struct mii_bus *bus, int addr, int reg, u16 value)
 {
 	struct davinci_emac_priv *priv = bus->priv;
-	while (readl(priv->adap_mdio + EMAC_MDIO_USERACCESS0) & MDIO_USERACCESS0_GO);
+	int ret;
+
+	ret = wait_for_user_access(priv, NULL);
+	if (ret)
+		return ret;
 
 	dev_dbg(priv->dev, "davinci_miibus_write: addr=0x%02x reg=0x%02x value=0x%04x\n",
 		   addr, reg, value);
@@ -146,10 +178,7 @@ static int davinci_miibus_write(struct mii_bus *bus, int addr, int reg, u16 valu
 				(value & 0xffff),
 		priv->adap_mdio + EMAC_MDIO_USERACCESS0);
 
-	/* Wait for command to complete */
-	while (readl(priv->adap_mdio + EMAC_MDIO_USERACCESS0) & MDIO_USERACCESS0_GO);
-
-	return 0;
+	return wait_for_user_access(priv, NULL);
 }
 
 static int davinci_emac_get_ethaddr(struct eth_device *edev, unsigned char *adr)
-- 
2.19.1


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  parent reply	other threads:[~2018-12-14 14:17 UTC|newest]

Thread overview: 30+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-12-14 14:17 [PATCH 00/23] AM3517 support Sascha Hauer
2018-12-14 14:17 ` [PATCH 01/23] net: davinci-emac: fix buggy channel tear down Sascha Hauer
2018-12-14 14:17 ` Sascha Hauer [this message]
2018-12-14 14:17 ` [PATCH 03/23] net: davinci-emac: switch to device tree support Sascha Hauer
2018-12-14 14:17 ` [PATCH 04/23] mci: omap: Improve error handling Sascha Hauer
2018-12-14 14:17 ` [PATCH 05/23] mci: omap: use IS_ENABLED() rather than #ifdef Sascha Hauer
2018-12-14 14:17 ` [PATCH 06/23] mtd: nand: omap: Use dev_dbg when a struct device * is available Sascha Hauer
2018-12-14 14:17 ` [PATCH 07/23] mtd: nand: omap: Fix hamming correct return values Sascha Hauer
2018-12-14 14:17 ` [PATCH 08/23] mtd: nand: omap: Disable subpage reads in hardware ecc mode Sascha Hauer
2018-12-14 14:17 ` [PATCH 09/23] mtd: nand: omap: remove unused function argument Sascha Hauer
2018-12-14 14:17 ` [PATCH 10/23] mtd: nand: omap: fix bch8_hw_romcode ecc layout Sascha Hauer
2018-12-14 14:17 ` [PATCH 11/23] mtd: nand: omap: set eccbytes correctly Sascha Hauer
2018-12-14 14:17 ` [PATCH 12/23] mtd: nand: omap: unbreak BCH8 support Sascha Hauer
2018-12-14 14:17 ` [PATCH 13/23] ARM: omap: Add missing include Sascha Hauer
2018-12-14 14:17 ` [PATCH 14/23] ARM: omap: dmtimer: Turn into a driver Sascha Hauer
2018-12-17 13:37   ` Teresa Remmet
2018-12-18  7:46     ` Sascha Hauer
2018-12-14 14:17 ` [PATCH 15/23] ARM: omap: 32ktimer: " Sascha Hauer
2018-12-14 14:17 ` [PATCH 16/23] ARM: omap: Add AM35XX support Sascha Hauer
2018-12-14 14:17 ` [PATCH 17/23] ARM: omap: enable am33xx_uart_soft_reset for AM35xx Sascha Hauer
2018-12-14 14:17 ` [PATCH 18/23] ARM: omap3: Add support for reset reason detection Sascha Hauer
2018-12-14 14:17 ` [PATCH 19/23] ARM: omap: Add AM3517 specific mux configuration Sascha Hauer
2018-12-14 14:17 ` [PATCH 20/23] ARM: omap: Add emif4 support for AM3517 Sascha Hauer
2018-12-14 14:17 ` [PATCH 21/23] ARM: omap: AM3517: Change default clock rate " Sascha Hauer
2018-12-14 14:17 ` [PATCH 22/23] ARM: omap: Add board support for WAGO pfc200 platform Sascha Hauer
2019-01-07 11:40   ` Heinrich.Toews
2019-01-07 11:46     ` Sascha Hauer
2018-12-14 14:17 ` [PATCH 23/23] ARM: omap: am33xx_defconfig: Enable more boards and rename Sascha Hauer
2018-12-14 16:22 ` [PATCH 00/23] AM3517 support Ladislav Michl
2018-12-14 19:32   ` Sascha Hauer

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