Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1759007Ab3GZRgD (ORCPT ); Fri, 26 Jul 2013 13:36:03 -0400 Received: from mail-ob0-f181.google.com ([209.85.214.181]:38750 "EHLO mail-ob0-f181.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751080Ab3GZRgA (ORCPT ); Fri, 26 Jul 2013 13:36:00 -0400 MIME-Version: 1.0 In-Reply-To: <003e01ce89f3$4cdb45e0$e691d1a0$@samsung.com> References: <003e01ce89f3$4cdb45e0$e691d1a0$@samsung.com> Date: Fri, 26 Jul 2013 10:35:59 -0700 X-Google-Sender-Auth: wMG2u-MUdD87QxOCjTTZHYiaMZE Message-ID: Subject: Re: [PATCH v8 08/12] iommu/exynos: remove prefetch buffer setting when enabling System MMU From: Grant Grundler To: Cho KyongHo Cc: Linux ARM Kernel , Linux IOMMU , Linux Kernel , Linux Samsung SOC , Hyunwoong Kim , Joerg Roedel , Kukjin Kim , Prathyush , Rahul Sharma , Subash Patel , Keyyoung Park , Grant Grundler , Antonios Motakis , kvmarm@lists.cs.columbia.edu, Sachin Kamat Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3532 Lines: 99 On Fri, Jul 26, 2013 at 4:28 AM, Cho KyongHo wrote: > Prefetch buffer must be handled accurately, exact range of a buffer, > frame by frame manually. Otherwise, it may causes page fault or > deadlock in System MMU. > Thus this patch removes prefetch buffer setting when System MMU is > initialized(enabled). > > Signed-off-by: Cho KyongHo Reviewed-by: Grant Grundler BTW, cscope doesn't find any callers of exynos_sysmmu_enable(). Want to submit another patch to remove it? (Note I'm talking about exynos_sysmmu_enable() without "__" prefix). cheers, grant > --- > drivers/iommu/exynos-iommu.c | 32 +++++++++++++++++++++++++++----- > 1 files changed, 27 insertions(+), 5 deletions(-) > > diff --git a/drivers/iommu/exynos-iommu.c b/drivers/iommu/exynos-iommu.c > index cfc02ed..87f6bb7 100644 > --- a/drivers/iommu/exynos-iommu.c > +++ b/drivers/iommu/exynos-iommu.c > @@ -80,6 +80,8 @@ > #define CTRL_BLOCK 0x7 > #define CTRL_DISABLE 0x0 > > +#define CFG_FLPDCACHE (1 << 20) /* System MMU 3.2+ only */ > + > #define REG_MMU_CTRL 0x000 > #define REG_MMU_CFG 0x004 > #define REG_MMU_STATUS 0x008 > @@ -96,6 +98,9 @@ > > #define REG_MMU_VERSION 0x034 > > +#define MMU_MAJ_VER(reg) (reg >> 28) > +#define MMU_MIN_VER(reg) ((reg >> 21) & 0x7F) > + > #define REG_PB0_SADDR 0x04C > #define REG_PB0_EADDR 0x050 > #define REG_PB1_SADDR 0x054 > @@ -200,6 +205,22 @@ static bool is_sysmmu_active(struct sysmmu_drvdata *data) > return data->activations > 0; > } > > +static unsigned int __sysmmu_version(struct sysmmu_drvdata *data, > + int idx, unsigned int *minor) > +{ > + unsigned long major; > + > + major = readl(data->sfrbases[idx] + REG_MMU_VERSION); > + > + if (minor) > + *minor = MMU_MIN_VER(major); > + > + if (MMU_MAJ_VER(major) > 3) > + return 1; > + > + return MMU_MAJ_VER(major); > +} > + > static void sysmmu_unblock(void __iomem *sfrbase) > { > __raw_writel(CTRL_ENABLE, sfrbase + REG_MMU_CTRL); > @@ -460,14 +481,15 @@ static int __exynos_sysmmu_enable(struct sysmmu_drvdata *data, > data->pgtable = pgtable; > > for (i = 0; i < data->nsfrs; i++) { > + unsigned int min; > + > __sysmmu_set_ptbase(data->sfrbases[i], pgtable); > > - if ((readl(data->sfrbases[i] + REG_MMU_VERSION) >> 28) == 3) { > - /* System MMU version is 3.x */ > - __raw_writel((1 << 12) | (2 << 28), > + if ((__sysmmu_version(data, i, &min) == 3) && (min > 1)) { > + unsigned long cfg; > + cfg = __raw_readl(data->sfrbases[i] + REG_MMU_CFG); > + __raw_writel(cfg | CFG_FLPDCACHE, > data->sfrbases[i] + REG_MMU_CFG); > - __sysmmu_set_prefbuf(data->sfrbases[i], 0, -1, 0); > - __sysmmu_set_prefbuf(data->sfrbases[i], 0, -1, 1); > } > > __raw_writel(CTRL_ENABLE, data->sfrbases[i] + REG_MMU_CTRL); > -- > 1.7.2.5 > > -- 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/