[U-Boot] [PATCH v2 1/2] mx6cuboxi: Fix Ethernet PHY detection problem

[Fabio Estevam]

mx6cuboxi sometimes fails to recognize the Ethernet PHY:

Net:   Phy 0 not found

The explanation for this behavior comes from from Rabeeh Khoury:

"The LED_ACT pin on the carrier-one boards had a pull down that
forces the phy address to 0x0; where on CuBox-i and the production
HummingBoard that pin is connected directly to LED that depending
on the pull down strength of the LED it might be sampled as '0' or '1' thus
the phy address might appear as either address 0x0 or 0x4."

"This is AR8035 implementation; in reset stage the LED pin is configured as
input, and pull up/down does matter. In this case it configures the PHY
address.

After reset is deasserted the same LED pin becomes output and then
according to the previous pull/up it should be active high/low"

One way to properly fix this behavior is to place external pull-up/down
resistors in the LED line, but from a software standpoint we can fix it 
by telling phy_find_by_mask() to scan the PHY at addresses
0x0 and 0x4.

Reported-by: Vagrant Cascadian <vagrant at aikidev.net>
Signed-off-by: Rabeeh Khoury <rabeeh at solid-run.com>
Signed-off-by: Fabio Estevam <fabio.estevam at freescale.com>
---
Changes since v1:
- Explain what the proper hardware fix would be as suggested by Nikolay
- Remove error message from fec_probe as this function already prints on error.

 board/solidrun/mx6cuboxi/mx6cuboxi.c | 29 ++++++++++++++++++++++++++++-
 1 file changed, 28 insertions(+), 1 deletion(-)

diff --git a/board/solidrun/mx6cuboxi/mx6cuboxi.c b/board/solidrun/mx6cuboxi/mx6cuboxi.c
index 9aa0259..e83d2fe 100644
--- a/board/solidrun/mx6cuboxi/mx6cuboxi.c
+++ b/board/solidrun/mx6cuboxi/mx6cuboxi.c
@@ -25,6 +25,7 @@
 #include <asm/imx-common/video.h>
 #include <mmc.h>
 #include <fsl_esdhc.h>
+#include <malloc.h>
 #include <miiphy.h>
 #include <netdev.h>
 #include <asm/arch/crm_regs.h>
@@ -152,9 +153,14 @@ int board_phy_config(struct phy_device *phydev)
 	return 0;
 }
 
+/* On Cuboxi Ethernet PHY can be located at addresses 0x0 or 0x4 */
+#define ETH_PHY_MASK	((1 << 0x0) | (1 << 0x4))
+
 int board_eth_init(bd_t *bis)
 {
 	struct iomuxc *const iomuxc_regs = (struct iomuxc *)IOMUXC_BASE_ADDR;
+	struct mii_dev *bus;
+	struct phy_device *phydev;
 
 	int ret = enable_fec_anatop_clock(ENET_25MHZ);
 	if (ret)
@@ -165,7 +171,28 @@ int board_eth_init(bd_t *bis)
 
 	setup_iomux_enet();
 
-	return cpu_eth_init(bis);
+	bus = fec_get_miibus(IMX_FEC_BASE, -1);
+	if (!bus)
+		return -EINVAL;
+
+	phydev = phy_find_by_mask(bus, ETH_PHY_MASK, PHY_INTERFACE_MODE_RGMII);
+	if (!phydev) {
+		ret = -EINVAL;
+		goto free_bus;
+	}
+
+	debug("using phy at address %d\n", phydev->addr);
+	ret = fec_probe(bis, -1, IMX_FEC_BASE, bus, phydev);
+	if (ret)
+		goto free_phydev;
+
+	return 0;
+
+free_phydev:
+	free(phydev);
+free_bus:
+	free(bus);
+	return ret;
 }
 
 #ifdef CONFIG_VIDEO_IPUV3
-- 
1.9.1