Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751788AbdISOnW convert rfc822-to-8bit (ORCPT ); Tue, 19 Sep 2017 10:43:22 -0400 Received: from mail.free-electrons.com ([62.4.15.54]:40556 "EHLO mail.free-electrons.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751751AbdISOnT (ORCPT ); Tue, 19 Sep 2017 10:43:19 -0400 From: Gregory CLEMENT To: Jan Luebbe Cc: Andrew Lunn , Thomas Petazzoni , Jason Cooper , linux-pci@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, kernel@pengutronix.de Subject: Re: [PATCH 1/2] bus: mbus: fix window size calculation for 4GB windows References: <20170828152517.24506-1-jlu@pengutronix.de> <20170828152517.24506-2-jlu@pengutronix.de> Date: Tue, 19 Sep 2017 16:43:18 +0200 In-Reply-To: <20170828152517.24506-2-jlu@pengutronix.de> (Jan Luebbe's message of "Mon, 28 Aug 2017 17:25:16 +0200") Message-ID: <87wp4urbp5.fsf@free-electrons.com> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/25.2 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8BIT Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2276 Lines: 70 Hi Jan, On lun., août 28 2017, Jan Luebbe wrote: > At least the Armada XP SoC supports 4GB on a single DRAM window. Because > the size register values contain the actual size - 1, the MSB is set in > that case. For example, the SDRAM window's control register's value is > 0xffffffe1 for 4GB (bits 31 to 24 contain the size). > > The MBUS driver reads back each window's size from registers and > calculates the actual size as (control_reg | ~DDR_SIZE_MASK) + 1, which > overflows for 32 bit values, resulting in other miscalculations further > on (a bad RAM window for the CESA crypto engine calculated by > mvebu_mbus_setup_cpu_target_nooverlap() in my case). > > This patch changes the type in 'struct mbus_dram_window' from u32 to > u64, which allows us to keep using the same register calculation code in > most MBUS-using drivers (which calculate ->size - 1 again). > Your patch looks good, but as it is a fix we should also apply it on stable, could you provide the commit to fix? Thanks, Gregory > Signed-off-by: Jan Luebbe > --- > drivers/bus/mvebu-mbus.c | 2 +- > include/linux/mbus.h | 4 ++-- > 2 files changed, 3 insertions(+), 3 deletions(-) > > diff --git a/drivers/bus/mvebu-mbus.c b/drivers/bus/mvebu-mbus.c > index c7f396903184..70db4d5638a6 100644 > --- a/drivers/bus/mvebu-mbus.c > +++ b/drivers/bus/mvebu-mbus.c > @@ -720,7 +720,7 @@ mvebu_mbus_default_setup_cpu_target(struct mvebu_mbus_state *mbus) > if (mbus->hw_io_coherency) > w->mbus_attr |= ATTR_HW_COHERENCY; > w->base = base & DDR_BASE_CS_LOW_MASK; > - w->size = (size | ~DDR_SIZE_MASK) + 1; > + w->size = (u64)(size | ~DDR_SIZE_MASK) + 1; > } > } > mvebu_mbus_dram_info.num_cs = cs; > diff --git a/include/linux/mbus.h b/include/linux/mbus.h > index 0d3f14fd2621..4773145246ed 100644 > --- a/include/linux/mbus.h > +++ b/include/linux/mbus.h > @@ -31,8 +31,8 @@ struct mbus_dram_target_info > struct mbus_dram_window { > u8 cs_index; > u8 mbus_attr; > - u32 base; > - u32 size; > + u64 base; > + u64 size; > } cs[4]; > }; > > -- > 2.11.0 > -- Gregory Clement, Free Electrons Kernel, drivers, real-time and embedded Linux development, consulting, training and support. http://free-electrons.com