Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754969Ab3JCPPh (ORCPT ); Thu, 3 Oct 2013 11:15:37 -0400 Received: from mail-bk0-f52.google.com ([209.85.214.52]:57306 "EHLO mail-bk0-f52.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753775Ab3JCPPe (ORCPT ); Thu, 3 Oct 2013 11:15:34 -0400 From: Sebastian Hesselbarth To: Andrew Lunn CC: Jason Cooper , Russell King , Grant Likely , Benjamin Herrenschmidt , Jason Gunthorpe , Ezequiel Garcia , , Date: Thu, 03 Oct 2013 17:15:05 +0200 Message-ID: <1417ee2ae58.2784.107cef0f820c2f5d7b7f41463071c310@gmail.com> In-Reply-To: <20131003134724.GD20056@lunn.ch> References: <1380804294-13726-1-git-send-email-sebastian.hesselbarth@gmail.com> <20131003134724.GD20056@lunn.ch> User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:9.0) Gecko/20111222 Thunderbird/9.0.1 AquaMail/1.2.5.5 (build: 2100355) Subject: Re: [PATCH 1/2] ARM: kirkwood: retain MAC address for DT ethernet Content-Type: text/plain; charset="us-ascii"; format=flowed Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 5106 Lines: 132 On October 3, 2013 3:47:24 PM Andrew Lunn wrote: > 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? Ccframework is up when calling this. I suggest to call clk_is_enabled and also skip the fixup if it isn't. Clk_prepare_enable ist quite useless, as register contents will suffer what this workaround is about. I send an updated v2 later but someone will have to test as I don't have kirkwood around till next week. > 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/