From: Eric Auger <eric.auger@linaro.org>
To: Peter Crosthwaite <crosthwaitepeter@gmail.com>,
Markus Armbruster <armbru@redhat.com>
Cc: Peter Maydell <peter.maydell@linaro.org>,
eric.auger@st.com, thomas.lendacky@amd.com,
Patch Tracking <patches@linaro.org>,
"qemu-devel@nongnu.org Developers" <qemu-devel@nongnu.org>,
Alex Williamson <alex.williamson@redhat.com>,
qemu-arm@nongnu.org, suravee.suthikulpanit@amd.com,
Paolo Bonzini <pbonzini@redhat.com>,
b.reynal@virtualopensystems.com, christoffer.dall@linaro.org
Subject: Re: [Qemu-devel] [RESEND RFC 4/6] device_tree: introduce qemu_fdt_getprop_optional
Date: Thu, 3 Dec 2015 16:48:39 +0100 [thread overview]
Message-ID: <56606457.1000906@linaro.org> (raw)
In-Reply-To: <CAPokK=phO1o4cu17QU2Kt2j_mRKk6qWsCgOB0dP=7s8S_3wx7g@mail.gmail.com>
Hi Peter,
On 11/27/2015 08:38 PM, Peter Crosthwaite wrote:
> On Thu, Nov 19, 2015 at 7:22 AM, Eric Auger <eric.auger@linaro.org> wrote:
>> Current qemu_fdt_getprop exits if the property is not found. It is
>> sometimes needed to read an optional property, in which case we do
>> not wish to exit but simply returns a null value.
>>
>> This is what this new qemu_fdt_getprop_optional function does.
>>
>> Signed-off-by: Eric Auger <eric.auger@linaro.org>
>> ---
>> device_tree.c | 17 +++++++++++++++++
>> include/sysemu/device_tree.h | 2 ++
>> 2 files changed, 19 insertions(+)
>>
>> diff --git a/device_tree.c b/device_tree.c
>> index f184e3c..a318683 100644
>> --- a/device_tree.c
>> +++ b/device_tree.c
>> @@ -280,6 +280,23 @@ const void *qemu_fdt_getprop(void *fdt, const char *node_path,
>> return r;
>> }
>>
>> +const void *qemu_fdt_getprop_optional(void *fdt, const char *node_path,
>> + const char *property, bool optional, int *lenp)
>> +{
>> + int len;
>> + const void *r;
>> + if (!lenp) {
>> + lenp = &len;
>> + }
>> + r = fdt_getprop(fdt, findnode_nofail(fdt, node_path), property, lenp);
>> + if (!r && !optional) {
>> + error_report("%s: Couldn't get %s/%s: %s", __func__,
>> + node_path, property, fdt_strerror(*lenp));
>> + exit(1);
>> + }
>> + return r;
>> +}
>> +
>
> The real problem here is that the device-tree API is self-asserting.
> This looks the old _nofail system that we removed but just named in
> reverse. The correct solution here is to use the Error API properly.
> Convert qemu_fdt_getprop to accept an Error **, and all existing users
> are converted to pass &error_fatal. This will preserve existing
> behaviour. Then to use the API with your optional semantic your pass
> NULL for the Error **.
OK I will implement your proposal. Thanks for your time.
Best Regards
Eric
>
> Regards,
> Peter
>
>> uint32_t qemu_fdt_getprop_cell(void *fdt, const char *node_path,
>> const char *property)
>> {
>> diff --git a/include/sysemu/device_tree.h b/include/sysemu/device_tree.h
>> index f9e6e6e..10cbe8e 100644
>> --- a/include/sysemu/device_tree.h
>> +++ b/include/sysemu/device_tree.h
>> @@ -34,6 +34,8 @@ int qemu_fdt_setprop_phandle(void *fdt, const char *node_path,
>> const char *target_node_path);
>> const void *qemu_fdt_getprop(void *fdt, const char *node_path,
>> const char *property, int *lenp);
>> +const void *qemu_fdt_getprop_optional(void *fdt, const char *node_path,
>> + const char *property, bool optional, int *lenp);
>> uint32_t qemu_fdt_getprop_cell(void *fdt, const char *node_path,
>> const char *property);
>> uint32_t qemu_fdt_get_phandle(void *fdt, const char *path);
>> --
>> 1.8.3.2
>>
>>
next prev parent reply other threads:[~2015-12-03 15:49 UTC|newest]
Thread overview: 28+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-11-19 15:22 [Qemu-devel] [RESEND RFC 0/6] AMD XGBE KVM platform passthrough Eric Auger
2015-11-19 15:22 ` [Qemu-devel] [RESEND RFC 1/6] hw/vfio/platform: amd-xgbe device Eric Auger
2015-11-25 14:35 ` Alex Bennée
2015-11-19 15:22 ` [Qemu-devel] [RESEND RFC 2/6] device_tree: introduce load_device_tree_from_sysfs Eric Auger
2015-11-25 15:38 ` Alex Bennée
2015-11-26 10:57 ` Thomas Huth
2015-12-03 15:19 ` Eric Auger
2015-11-19 15:22 ` [Qemu-devel] [RESEND RFC 3/6] device_tree: introduce qemu_fdt_node_path Eric Auger
2015-11-26 12:06 ` Alex Bennée
2015-12-03 15:44 ` Eric Auger
2015-11-19 15:22 ` [Qemu-devel] [RESEND RFC 4/6] device_tree: introduce qemu_fdt_getprop_optional Eric Auger
2015-11-26 13:13 ` Alex Bennée
2015-11-27 19:38 ` Peter Crosthwaite
2015-12-03 15:48 ` Eric Auger [this message]
2015-11-19 15:22 ` [Qemu-devel] [RESEND RFC 5/6] hw/arm/sysbus-fdt: helpers for clock node generation Eric Auger
2015-11-26 16:06 ` Alex Bennée
2015-12-17 9:26 ` Eric Auger
2015-12-17 13:28 ` Alex Bennée
2015-12-17 13:44 ` Peter Maydell
2015-12-17 15:13 ` Alex Bennée
2015-12-17 15:25 ` Eric Auger
2015-12-17 15:56 ` Alex Bennée
2015-11-19 15:22 ` [Qemu-devel] [RESEND RFC 6/6] hw/arm/sysbus-fdt: enable amd-xgbe dynamic instantiation Eric Auger
2015-11-26 17:14 ` Alex Bennée
2015-12-03 16:17 ` Eric Auger
2015-11-19 23:44 ` [Qemu-devel] [RESEND RFC 0/6] AMD XGBE KVM platform passthrough Alex Williamson
2015-11-20 15:10 ` Eric Auger
2015-11-25 10:29 ` Christoffer Dall
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