Kirkwood ethernet controllers suffer from loosing MAC register content
on gated clocks. In the past this was prevented by not gating the ethernet
controller clocks. With DT support for mv643xx_eth and corresponding
nodes available, a different approach is more reasonable.

This patch replaces the former clock gating workaround by parsing the
ethernet controller nodes for *invalid* MAC addresses and overwrites
the local-mac-address property with MAC register contents early. The
clock can now properly gated in modular mv643xx_eth and DT agnostic
boot loader scenarios because mv643xx_eth will find the stored MAC
in the corresponding MAC address property.

Signed-off-by: Sebastian Hesselbarth <sebastian.hesselba...@gmail.com>
---
Cc: David Miller <da...@davemloft.net>
Cc: Lennert Buytenhek <buyt...@wantstofly.org>
Cc: Jason Cooper <ja...@lakedaemon.net>
Cc: Andrew Lunn <and...@lunn.ch>
Cc: Benjamin Herrenschmidt <b...@kernel.crashing.org>
Cc: net...@vger.kernel.org
Cc: linux-arm-ker...@lists.infradead.org
Cc: linuxppc-dev@lists.ozlabs.org
Cc: linux-ker...@vger.kernel.org
---
 arch/arm/mach-kirkwood/board-dt.c |   67 +++++++++++++++++++++++++++++--------
 1 file changed, 53 insertions(+), 14 deletions(-)

diff --git a/arch/arm/mach-kirkwood/board-dt.c 
b/arch/arm/mach-kirkwood/board-dt.c
index a86b41c..0aad9f7 100644
--- a/arch/arm/mach-kirkwood/board-dt.c
+++ b/arch/arm/mach-kirkwood/board-dt.c
@@ -13,6 +13,8 @@
 #include <linux/kernel.h>
 #include <linux/init.h>
 #include <linux/of.h>
+#include <linux/of_address.h>
+#include <linux/of_net.h>
 #include <linux/of_platform.h>
 #include <linux/clk-provider.h>
 #include <linux/clk/mvebu.h>
@@ -31,6 +33,56 @@ static struct of_device_id kirkwood_dt_match_table[] 
__initdata = {
 };
 
 /*
+ * Kirkwood ethernet controllers suffer from loosing the MAC address
+ * register content on gated clocks. Rather than always ungate the
+ * clocks, we get the MAC address early and put it into DT for those
+ * boot loaders that don't provide a valid MAC address property.
+ */
+#define ETH_MAC_ADDR_L(n)      (0x400 + ((n) * 0x400) + 0x14)
+#define ETH_MAC_ADDR_H(n)      (0x400 + ((n) * 0x400) + 0x18)
+
+static void __init kirkwood_dt_eth_quirk(void)
+{
+       struct device_node *np;
+
+       for_each_compatible_node(np, NULL, "marvell,orion-eth") {
+               struct device_node *pnp;
+               void __iomem *base;
+
+               if (!of_device_is_available(np))
+                       continue;
+
+               base = of_iomap(np, 0);
+               if (!base)
+                       continue;
+
+               for_each_available_child_of_node(np, pnp) {
+                       const void *mac_addr;
+                       struct property *p;
+                       u32 n, reg[2];
+
+                       mac_addr = of_get_mac_address(pnp);
+                       if (mac_addr)
+                               continue;
+
+                       p = of_find_property(pnp, "local-mac-address", NULL);
+                       if (!p || p->length != 6)
+                               continue;
+
+                       if (of_property_read_u32(pnp, "reg", &n))
+                               continue;
+
+                       reg[0] = cpu_to_be32(readl(base + ETH_MAC_ADDR_H(n)));
+                       reg[1] = cpu_to_be32(readl(base +
+                                                  ETH_MAC_ADDR_L(n)) << 16);
+                       memcpy((void *)p->value, reg, 6);
+               }
+
+               iounmap(base);
+       }
+}
+
+/*
  * There are still devices that doesn't know about DT yet.  Get clock
  * gates here and add a clock lookup alias, so that old platform
  * devices still work.
@@ -42,7 +94,6 @@ static void __init kirkwood_legacy_clk_init(void)
        struct device_node *np = of_find_compatible_node(
                NULL, NULL, "marvell,kirkwood-gating-clock");
        struct of_phandle_args clkspec;
-       struct clk *clk;
 
        clkspec.np = np;
        clkspec.args_count = 1;
@@ -58,19 +109,6 @@ static void __init kirkwood_legacy_clk_init(void)
        clkspec.args[0] = CGC_BIT_SDIO;
        orion_clkdev_add(NULL, "mvsdio",
                         of_clk_get_from_provider(&clkspec));
-
-       /*
-        * The ethernet interfaces forget the MAC address assigned by
-        * u-boot if the clocks are turned off. Until proper DT support
-        * is available we always enable them for now.
-        */
-       clkspec.args[0] = CGC_BIT_GE0;
-       clk = of_clk_get_from_provider(&clkspec);
-       clk_prepare_enable(clk);
-
-       clkspec.args[0] = CGC_BIT_GE1;
-       clk = of_clk_get_from_provider(&clkspec);
-       clk_prepare_enable(clk);
 }
 
 static void __init kirkwood_of_clk_init(void)
@@ -97,6 +135,7 @@ static void __init kirkwood_dt_init(void)
 
        /* Setup root of clk tree */
        kirkwood_of_clk_init();
+       kirkwood_dt_eth_quirk();
 
        kirkwood_cpuidle_init();
 
-- 
1.7.10.4

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