[PATCH 1/2] ARM: kirkwood: retain MAC address for DT ethernet

[sebastian.hesselbarth@gmail.com (Sebastian Hesselbarth)]

Ethernet IP on Kirkwood SoCs loose their MAC address register content
if clock gated. To allow modular ethernet driver setups and gated clocks
also on non-DT capable bootloaders, we fixup port device nodes with no
valid MAC address property. This patch copies MAC address register
contents set up by bootloaders early, notably before ethernet clocks
are gated. While at it, also reorder call sequence in _dt_init.

Signed-off-by: Sebastian Hesselbarth <sebastian.hesselbarth@gmail.com>
---
- Added Benjamin and Grant who where part of the discussion last time
  and gave valuable input on DT fixups.
- Patches are based on v3.12-rc1 and depend on latest mv643xx_eth
  fixes applied yesterday by David Miller [1].

[1] https://git.kernel.org/cgit/linux/kernel/git/davem/net.git/commit/?id=569943d0639c85a451ea853087cbd5f738247dd9

Cc: Jason Cooper <jason@lakedaemon.net>
Cc: Andrew Lunn <andrew@lunn.ch>
Cc: Russell King <linux@arm.linux.org.uk>
Cc: Grant Likely <grant.likely@linaro.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Jason Gunthorpe <jgunthorpe@obsidianresearch.com>
Cc: Ezequiel Garcia <ezequiel.garcia@free-electrons.com>
Cc: linux-arm-kernel at lists.infradead.org
Cc: linux-kernel at vger.kernel.org
---
 arch/arm/mach-kirkwood/board-dt.c |   72 +++++++++++++++++++++++++++++++++++--
 1 file changed, 69 insertions(+), 3 deletions(-)

diff --git a/arch/arm/mach-kirkwood/board-dt.c b/arch/arm/mach-kirkwood/board-dt.c
index 82d3ad8..a2974ad 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/clocksource.h>
@@ -66,6 +68,71 @@ static void __init kirkwood_legacy_clk_init(void)
 	clk_prepare_enable(clk);
 }
 
+#define MV643XX_ETH_MAC_ADDR_LOW	0x0414
+#define MV643XX_ETH_MAC_ADDR_HIGH	0x0418
+
+static void __init kirkwood_dt_eth_fixup(void)
+{
+	struct device_node *np;
+
+	/*
+	 * The ethernet interfaces forget the MAC address assigned by u-boot
+	 * if the clocks are turned off. Usually, u-boot on kirkwood boards
+	 * has no DT support to properly set local-mac-address property.
+	 * As a workaround, we get the MAC address from mv643xx_eth registers
+	 * and update the port device node if no valid MAC address is set.
+	 */
+	for_each_compatible_node(np, NULL, "marvell,kirkwood-eth-port") {
+		struct device_node *pnp = of_get_parent(np);
+		struct property *pmac;
+		void __iomem *io;
+		u8 *macaddr;
+		u32 reg;
+
+		if (!pnp || !of_device_is_available(pnp))
+			continue;
+
+		if (of_get_mac_address(np))
+			continue;
+
+		pr_err(FW_BUG "%s: local-mac-address is not set\n",
+		       np->full_name);
+
+		io = of_iomap(pnp, 0);
+		if (!io)
+			continue;
+
+		pmac = kzalloc(sizeof(*pmac) + 6, GFP_KERNEL);
+		if (!pmac) {
+			iounmap(io);
+			continue;
+		}
+
+		pmac->value = pmac + 1;
+		pmac->length = 6;
+		pmac->name = kstrdup("local-mac-address", GFP_KERNEL);
+		if (!pmac->name) {
+			kfree(pmac);
+			iounmap(io);
+			continue;
+		}
+
+		macaddr = pmac->value;
+		reg = readl(io + MV643XX_ETH_MAC_ADDR_HIGH);
+		macaddr[0] = (reg >> 24) & 0xff;
+		macaddr[1] = (reg >> 16) & 0xff;
+		macaddr[2] = (reg >> 8) & 0xff;
+		macaddr[3] = reg & 0xff;
+
+		reg = readl(io + MV643XX_ETH_MAC_ADDR_LOW);
+		macaddr[4] = (reg >> 8) & 0xff;
+		macaddr[5] = reg & 0xff;
+
+		of_update_property(np, pmac);
+		iounmap(io);
+	}
+}
+
 static void __init kirkwood_dt_time_init(void)
 {
 	of_clk_init(NULL);
@@ -97,11 +164,10 @@ static void __init kirkwood_dt_init(void)
 	kirkwood_l2_init();
 
 	kirkwood_cpufreq_init();
-
+	kirkwood_cpuidle_init();
 	/* Setup clocks for legacy devices */
 	kirkwood_legacy_clk_init();
-
-	kirkwood_cpuidle_init();
+	kirkwood_dt_eth_fixup();
 
 #ifdef CONFIG_KEXEC
 	kexec_reinit = kirkwood_enable_pcie;
-- 
1.7.10.4