[U-Boot] [PATCH fix for v2014.10] sunxi: Fix gmac not working reliable on the Bananapi

[Hans de Goede]

In order for the gmac nic to work reliable on the Bananapi, we need to set
bits 10-12 GTXDC "GMAC Transmit Clock Delay Chain" of the GMAC clk register
(0x01c20164) to 3.

Without this about 9 out of 10 ethernet packets get lost, with this setting
there is no packet loss.

So far setting these bits is only necessary on the Bananapi, so this commit
solves this with a bit of #ifdef CONFIG_BANANAPI code. If in the future we
need to do something similar for other boards, we can create a specific
CONFIG_FOO option for this then.

Reported-by: Karsten Merker <merker at debian.org>
Signed-off-by: Hans de Goede <hdegoede at redhat.com>
Tested-by: Karsten Merker <merker at debian.org>
Tested-by: Zoltan HERPAI <wigyori at openwrt.org>
Tested-by: Tony Zhang <tony.zhang at lemaker.org>
Acked-by: Ian Campbell <ijc at hellion.org.uk>
---
 board/sunxi/gmac.c | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/board/sunxi/gmac.c b/board/sunxi/gmac.c
index e7ff952..6348d27 100644
--- a/board/sunxi/gmac.c
+++ b/board/sunxi/gmac.c
@@ -24,6 +24,15 @@ int sunxi_gmac_initialize(bd_t *bis)
 		CCM_GMAC_CTRL_GPIT_MII);
 #endif
 
+	/*
+	 * In order for the gmac nic to work reliable on the Bananapi, we
+	 * need to set bits 10-12 GTXDC "GMAC Transmit Clock Delay Chain"
+	 * of the GMAC clk register to 3.
+	 */
+#ifdef CONFIG_BANANAPI
+	setbits_le32(&ccm->gmac_clk_cfg, 0x3 << 10);
+#endif
+
 	/* Configure pin mux settings for GMAC */
 	for (pin = SUNXI_GPA(0); pin <= SUNXI_GPA(16); pin++) {
 #ifdef CONFIG_RGMII
-- 
2.1.0