[PATCH v2 1/2] ARM: kirkwood: retain MAC address for DT ethernet

[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 at gmail.com>
---
Changelog:
v1->v2:
- check for gated clock before accessing eth registers
  (Suggested by Andrew Lunn)

TBH, as there is no "official" clk_is_enabled but just the __clk_is_enabled
one, this is close to abuse of CCF API. Actually, there should either be an
clk_is_enabled or we enable the clock, copy a possible invalid MAC address
and disable the clock again. (Added Mike, who might have an opinion about
clk_is_enabled)

Cc: Jason Cooper <jason at lakedaemon.net>
Cc: Andrew Lunn <andrew at lunn.ch>
Cc: Russell King <linux at arm.linux.org.uk>
Cc: Grant Likely <grant.likely at linaro.org>
Cc: Benjamin Herrenschmidt <benh at kernel.crashing.org>
Cc: Jason Gunthorpe <jgunthorpe at obsidianresearch.com>
Cc: Ezequiel Garcia <ezequiel.garcia at free-electrons.com>
Cc: Mike Turquette <mturquette at linaro.org>
Cc: linux-arm-kernel at lists.infradead.org
Cc: linux-kernel at vger.kernel.org
---
 arch/arm/mach-kirkwood/board-dt.c |   77 +++++++++++++++++++++++++++++++++++--
 1 file changed, 74 insertions(+), 3 deletions(-)

diff --git a/arch/arm/mach-kirkwood/board-dt.c b/arch/arm/mach-kirkwood/board-dt.c
index 82d3ad8..f5f35bb 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 +68,76 @@ 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 clk *clk;
+		struct property *pmac;
+		void __iomem *io;
+		u8 *macaddr;
+		u32 reg;
+
+		if (!pnp || !of_device_is_available(pnp))
+			continue;
+
+		clk = of_clk_get(pnp, 0);
+		if (!__clk_is_enabled(clk) || of_get_mac_address(np)) {
+			clk_put(clk);
+			continue;
+		}
+		clk_put(clk);
+
+		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 +169,10 @@ 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