Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754545Ab3JCNvj (ORCPT ); Thu, 3 Oct 2013 09:51:39 -0400 Received: from vps0.lunn.ch ([178.209.37.122]:39612 "EHLO vps0.lunn.ch" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753958Ab3JCNvi (ORCPT ); Thu, 3 Oct 2013 09:51:38 -0400 Date: Thu, 3 Oct 2013 15:47:24 +0200 From: Andrew Lunn To: Sebastian Hesselbarth Cc: Jason Cooper , Andrew Lunn , Russell King , Grant Likely , Benjamin Herrenschmidt , Jason Gunthorpe , Ezequiel Garcia , linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH 1/2] ARM: kirkwood: retain MAC address for DT ethernet Message-ID: <20131003134724.GD20056@lunn.ch> References: <1380804294-13726-1-git-send-email-sebastian.hesselbarth@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1380804294-13726-1-git-send-email-sebastian.hesselbarth@gmail.com> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 4503 Lines: 124 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 > --- > - 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 > Cc: Andrew Lunn > Cc: Russell King > Cc: Grant Likely > Cc: Benjamin Herrenschmidt > Cc: Jason Gunthorpe > Cc: Ezequiel Garcia > Cc: linux-arm-kernel@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 > #include > #include > +#include > +#include > #include > #include > #include > @@ -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 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/