On Thu, Oct 03, 2013 at 02:44:53PM +0200, Sebastian Hesselbarth wrote:
> 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.hesselba...@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 <ja...@lakedaemon.net>
> Cc: Andrew Lunn <and...@lunn.ch>
> Cc: Russell King <li...@arm.linux.org.uk>
> Cc: Grant Likely <grant.lik...@linaro.org>
> Cc: Benjamin Herrenschmidt <b...@kernel.crashing.org>
> Cc: Jason Gunthorpe <jguntho...@obsidianresearch.com>
> Cc: Ezequiel Garcia <ezequiel.gar...@free-electrons.com>
> Cc: linux-arm-ker...@lists.infradead.org
> Cc: linux-kernel@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;
Hi Sebastian
What happens if at this point, the ethernet clock is gated off? I
assume the CPU locks solid, requiring a power cycle.
It would be a bit of an odd situation, u-boot has disabled the clock,
yet we have a DT node for the device and no valid local-mac-address.
We do however know that Jason Gunthorpe u-boot does gate the second
ethernet for his board, so it is not completely impossible to hit this
situation, particularly when bringing up a new board.
Are we too early in the boot to actually use the clock information in
the node to find it, and clk_prepare_enable() it before making the
access?
Andrew
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