From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mx0a-001b2d01.pphosted.com (mx0a-001b2d01.pphosted.com [148.163.156.1]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 3vXrFq68QGzDqHq for ; Wed, 1 Mar 2017 07:46:07 +1100 (AEDT) Received: from pps.filterd (m0098399.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.16.0.20/8.16.0.20) with SMTP id v1SKjgEp019395 for ; Tue, 28 Feb 2017 15:46:05 -0500 Received: from e33.co.us.ibm.com (e33.co.us.ibm.com [32.97.110.151]) by mx0a-001b2d01.pphosted.com with ESMTP id 28wdxxqa6g-1 (version=TLSv1.2 cipher=AES256-SHA bits=256 verify=NOT) for ; Tue, 28 Feb 2017 15:46:05 -0500 Received: from localhost by e33.co.us.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Tue, 28 Feb 2017 13:46:04 -0700 From: Stewart Smith To: Matt Brown , linuxppc-dev@lists.ozlabs.org Subject: Re: [Patch v4] powerpc/powernv: add hdat attribute to sysfs In-Reply-To: <20170228075503.20387-1-matthew.brown.dev@gmail.com> References: <20170228075503.20387-1-matthew.brown.dev@gmail.com> Date: Wed, 01 Mar 2017 07:45:53 +1100 MIME-Version: 1.0 Content-Type: text/plain Message-Id: <87k28acada.fsf@linux.vnet.ibm.com> List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Matt Brown writes: > The HDAT data area is consumed by skiboot and turned into a device-tree. > In some cases we would like to look directly at the HDAT, so this patch > adds a sysfs node to allow it to be viewed. This is not possible through > /dev/mem as it is reserved memory which is stopped by the /dev/mem filter. > > Signed-off-by: Matt Brown > --- > Changes between v3 and v4: > - changed sysfs attribute permissions from 0444 to 0400 > - fixed makefile to be on same line > - fixed authorship/copyright info > - re-ordered includes > - changed hdat_info struct to a static struct > > --- > arch/powerpc/include/asm/opal.h | 1 + > arch/powerpc/platforms/powernv/Makefile | 2 +- > arch/powerpc/platforms/powernv/opal-hdat.c | 60 ++++++++++++++++++++++++++++++ > arch/powerpc/platforms/powernv/opal.c | 2 + > 4 files changed, 64 insertions(+), 1 deletion(-) > create mode 100644 arch/powerpc/platforms/powernv/opal-hdat.c > > diff --git a/arch/powerpc/include/asm/opal.h b/arch/powerpc/include/asm/opal.h > index 5c7db0f..b26944e 100644 > --- a/arch/powerpc/include/asm/opal.h > +++ b/arch/powerpc/include/asm/opal.h > @@ -277,6 +277,7 @@ extern int opal_async_comp_init(void); > extern int opal_sensor_init(void); > extern int opal_hmi_handler_init(void); > extern int opal_event_init(void); > +extern void opal_hdat_sysfs_init(void); > > extern int opal_machine_check(struct pt_regs *regs); > extern bool opal_mce_check_early_recovery(struct pt_regs *regs); > diff --git a/arch/powerpc/platforms/powernv/Makefile b/arch/powerpc/platforms/powernv/Makefile > index b5d98cb..3826b70 100644 > --- a/arch/powerpc/platforms/powernv/Makefile > +++ b/arch/powerpc/platforms/powernv/Makefile > @@ -2,7 +2,7 @@ obj-y += setup.o opal-wrappers.o opal.o opal-async.o idle.o > obj-y += opal-rtc.o opal-nvram.o opal-lpc.o opal-flash.o > obj-y += rng.o opal-elog.o opal-dump.o opal-sysparam.o opal-sensor.o > obj-y += opal-msglog.o opal-hmi.o opal-power.o opal-irqchip.o > -obj-y += opal-kmsg.o > +obj-y += opal-kmsg.o opal-hdat.o > > obj-$(CONFIG_SMP) += smp.o subcore.o subcore-asm.o > obj-$(CONFIG_PCI) += pci.o pci-ioda.o npu-dma.o > diff --git a/arch/powerpc/platforms/powernv/opal-hdat.c b/arch/powerpc/platforms/powernv/opal-hdat.c > new file mode 100644 > index 0000000..19647fd > --- /dev/null > +++ b/arch/powerpc/platforms/powernv/opal-hdat.c > @@ -0,0 +1,60 @@ > +/* > + * PowerNV OPAL HDAT interface > + * > + * Copyright 2017, Matt Brown, IBM Corp. > + * > + * This program is free software; you can redistribute it and/or > + * modify it under the terms of the GNU General Public License > + * as published by the Free Software Foundation; either version > + * 2 of the License, or (at your option) any later version. > + */ > + > +#include > +#include > +#include > +#include > + > +static struct { > + char *base; > + u64 size; > +} hdat_info; > + > +/* Read function for HDAT attribute in sysfs */ > +static ssize_t hdat_read(struct file *file, struct kobject *kobj, > + struct bin_attribute *bin_attr, char *to, > + loff_t pos, size_t count) > +{ > + if (!hdat_info.base) > + return -ENODEV; > + > + return memory_read_from_buffer(to, count, &pos, hdat_info.base, > + hdat_info.size); > +} > + > +/* HDAT attribute for sysfs */ > +static struct bin_attribute hdat_attr = { > + .attr = {.name = "hdat", .mode = 0400}, > + .read = hdat_read > +}; Why not BIN_ATTR_RO (like opal_export_symmap() does) ? (I have comments/thoughts on the OPAL side as well) -- Stewart Smith OPAL Architect, IBM.