[PATCH v4] 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>
Reviewed-by: Jason Gunthorpe <jgunthorpe at obsidianresearch.com>
Reviewed-by: Ezequiel Garcia <ezequiel.garcia at free-electrons.com>
Tested-by: Andrew Lunn <andrew at lunn.ch>
---
Just to make sure they don't get lost this time:
Added Jason's and Ezequiel's Reviewed-by to honor their constant reviews,
and Andrew's last Tested-by because I know he will be testing again.

Changelog:
v3->v4:
- drop clk_is_enabled (and dependency) due to possible abuse of the
  new function; enable/disable clk instead, remove gated clock warning
  (Suggested by Andrew Lunn, Uwe Kleine-Koenig, Mike Turquette)
- reduce FW_BUG to FW_INFO (Suggested by Andrew Lunn)
- proper cleanup of iomap, clk, nodes
v2->v3:
- make use of new public clk_is_enabled (adds dependency)
- add warning about gated clock && missing MAC property
  (Suggested by Jason Gunthorpe)
v1->v2:
- check for gated clock before accessing eth registers
  (Suggested by Andrew Lunn)

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 |   86 +++++++++++++++++++++++++++++++++++--
 1 file changed, 83 insertions(+), 3 deletions(-)

diff --git a/arch/arm/mach-kirkwood/board-dt.c b/arch/arm/mach-kirkwood/board-dt.c
index 82d3ad8..3ddd194 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 +68,85 @@ 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)
+			continue;
+
+		/* skip disabled nodes or nodes with valid MAC address*/
+		if (!of_device_is_available(pnp) || of_get_mac_address(np))
+			goto eth_fixup_skip;
+
+		clk = of_clk_get(pnp, 0);
+		if (IS_ERR(clk))
+			goto eth_fixup_skip;
+
+		io = of_iomap(pnp, 0);
+		if (!io)
+			goto eth_fixup_no_map;
+
+		/* ensure port clock is not gated to not hang CPU */
+		clk_prepare_enable(clk);
+
+		/* store MAC address register contents in local-mac-address */
+		pr_err(FW_INFO "%s: local-mac-address is not set\n",
+		       np->full_name);
+
+		pmac = kzalloc(sizeof(*pmac) + 6, GFP_KERNEL);
+		if (!pmac)
+			goto eth_fixup_no_mem;
+
+		pmac->value = pmac + 1;
+		pmac->length = 6;
+		pmac->name = kstrdup("local-mac-address", GFP_KERNEL);
+		if (!pmac->name) {
+			kfree(pmac);
+			goto eth_fixup_no_mem;
+		}
+
+		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);
+
+eth_fixup_no_mem:
+		iounmap(io);
+		clk_disable_unprepare(clk);
+eth_fixup_no_map:
+		clk_put(clk);
+eth_fixup_skip:
+		of_node_put(pnp);
+	}
+}
+
 static void __init kirkwood_dt_time_init(void)
 {
 	of_clk_init(NULL);
@@ -97,11 +178,10 @@ 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