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Re: [Qemu-arm] [Qemu-devel] [PATCH v6 2/8] device_tree: introduce load_d
From: |
Eric Auger |
Subject: |
Re: [Qemu-arm] [Qemu-devel] [PATCH v6 2/8] device_tree: introduce load_device_tree_from_sysfs |
Date: |
Mon, 1 Feb 2016 17:31:13 +0100 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:38.0) Gecko/20100101 Thunderbird/38.5.1 |
On 02/01/2016 05:27 PM, Rob Herring wrote:
> On Mon, Feb 1, 2016 at 10:22 AM, Eric Auger <address@hidden> wrote:
>> Hi Rob,
>> On 02/01/2016 05:15 PM, Rob Herring wrote:
>>> On Mon, Feb 1, 2016 at 7:51 AM, Eric Auger <address@hidden> wrote:
>>>> This function returns the host device tree blob from sysfs
>>>> (/proc/device-tree). It uses a recursive function inspired
>>>> from dtc read_fstree.
>>>>
>>>> Signed-off-by: Eric Auger <address@hidden>
>>>>
>>>> ---
>>>> v5 -> v6:
>>>> - fix some spelling mistakes
>>>> - error_report + exit replaced by error_setg
>>>> - const char *parent_node;
>>>> - use g_strdup_printf instead of g_strjoin
>>>> - add a doc comment for load_device_tree_from_sysfs
>>>> v1 -> v2:
>>>> - do not implement/expose read_fstree and load_device_tree_from_sysfs
>>>> if CONFIG_LINUX is not defined (lstat is not implemeted in mingw)
>>>> - correct indentation in read_fstree
>>>> - use /proc/device-tree symlink instead of /sys/firmware/devicetree/base
>>>> path (kernel.org/doc/Documentation/ABI/testing/sysfs-firmware-ofw)
>>>> - use g_file_get_contents in read_fstree
>>>> - introduce SYSFS_DT_BASEDIR macro and use strlen
>>>> - exit on error in load_device_tree_from_sysfs
>>>> - user error_setg
>>>>
>>>> RFC -> v1:
>>>> - remove runtime dependency on dtc binary and introduce read_fstree
>>>> ---
>>>> device_tree.c | 99
>>>> ++++++++++++++++++++++++++++++++++++++++++++
>>>> include/sysemu/device_tree.h | 8 ++++
>>>> 2 files changed, 107 insertions(+)
>>>>
>>>> diff --git a/device_tree.c b/device_tree.c
>>>> index a9f5f8e..3797182 100644
>>>> --- a/device_tree.c
>>>> +++ b/device_tree.c
>>>> @@ -17,6 +17,9 @@
>>>> #include <fcntl.h>
>>>> #include <unistd.h>
>>>> #include <stdlib.h>
>>>> +#ifdef CONFIG_LINUX
>>>> +#include <dirent.h>
>>>> +#endif
>>>>
>>>> #include "qemu-common.h"
>>>> #include "qemu/error-report.h"
>>>> @@ -117,6 +120,102 @@ fail:
>>>> return NULL;
>>>> }
>>>>
>>>> +#ifdef CONFIG_LINUX
>>>> +
>>>> +#define SYSFS_DT_BASEDIR "/proc/device-tree"
>>>
>>> Use the sysfs path (/sys/firmware/device-tree/ IIRC) as this is just a
>>> symlink to sysfs and /proc is considered the legacy path.
>> I used the sysfs originally but I eventually found:
>> https://www.kernel.org/doc/Documentation/ABI/testing/sysfs-firmware-ofw
>> which states:
>>
>> "Userspace must not use the /sys/firmware/devicetree/base
>> path directly, but instead should follow /proc/device-tree
>> symlink. It is possible that the absolute path will change
>> in the future, but the symlink is the stable ABI.
>> "
>>
>> Do you confirm this statement is outdated.
>
> Ah, no. My memory is just wrong. NM.
OK no problem.
Thanks for taking care
Best Regards
Eric
>
> Rob
>
[Qemu-arm] [PATCH v6 1/8] hw/vfio/platform: amd-xgbe device, Eric Auger, 2016/02/01
[Qemu-arm] [PATCH v6 4/8] device_tree: qemu_fdt_getprop converted to use the error API, Eric Auger, 2016/02/01
[Qemu-arm] [PATCH v6 3/8] device_tree: introduce qemu_fdt_node_path, Eric Auger, 2016/02/01
[Qemu-arm] [PATCH v6 5/8] device_tree: qemu_fdt_getprop_cell converted to use the error API, Eric Auger, 2016/02/01
[Qemu-arm] [PATCH v6 6/8] hw/arm/sysbus-fdt: helpers for clock node generation, Eric Auger, 2016/02/01
[Qemu-arm] [PATCH v6 7/8] hw/arm/sysbus-fdt: enable amd-xgbe dynamic instantiation, Eric Auger, 2016/02/01
[Qemu-arm] [PATCH v6 8/8] hw/arm/sysbus-fdt: remove qemu_fdt_setprop returned value check, Eric Auger, 2016/02/01