From: "wangyanan (Y)" <wangyanan55@huawei.com>
To: David Gibson <david@gibson.dropbear.id.au>
Cc: Peter Maydell <peter.maydell@linaro.org>,
Andrew Jones <drjones@redhat.com>,
"Michael S . Tsirkin" <mst@redhat.com>,
wanghaibin.wang@huawei.com, qemu-devel@nongnu.org,
Shannon Zhao <shannon.zhaosl@gmail.com>,
qemu-arm@nongnu.org, Alistair Francis <alistair.francis@wdc.com>,
prime.zeng@hisilicon.com, yangyicong@huawei.com,
yuzenghui@huawei.com, Igor Mammedov <imammedo@redhat.com>,
zhukeqian1@huawei.com, Jiajie Li <lijiajie11@huawei.com>
Subject: Re: [RFC PATCH v2 1/6] device_tree: Add qemu_fdt_add_path
Date: Sat, 17 Apr 2021 10:36:20 +0800 [thread overview]
Message-ID: <cd3408c2-6025-7a44-bbf6-d675467c5749@huawei.com> (raw)
In-Reply-To: <YHkYD+cCl9/GCxwJ@yekko.fritz.box>
Hi David,
On 2021/4/16 12:52, David Gibson wrote:
> On Tue, Apr 13, 2021 at 04:07:40PM +0800, Yanan Wang wrote:
>> From: Andrew Jones <drjones@redhat.com>
>>
>> qemu_fdt_add_path() works like qemu_fdt_add_subnode(), except
>> it also adds any missing subnodes in the path. We also tweak
>> an error message of qemu_fdt_add_subnode().
>>
>> We'll make use of this new function in a coming patch.
>>
>> Signed-off-by: Andrew Jones <drjones@redhat.com>
>> Signed-off-by: Yanan Wang <wangyanan55@huawei.com>
>> ---
>> include/sysemu/device_tree.h | 1 +
>> softmmu/device_tree.c | 45 ++++++++++++++++++++++++++++++++++--
>> 2 files changed, 44 insertions(+), 2 deletions(-)
>>
>> diff --git a/include/sysemu/device_tree.h b/include/sysemu/device_tree.h
>> index 8a2fe55622..ef060a9759 100644
>> --- a/include/sysemu/device_tree.h
>> +++ b/include/sysemu/device_tree.h
>> @@ -121,6 +121,7 @@ uint32_t qemu_fdt_get_phandle(void *fdt, const char *path);
>> uint32_t qemu_fdt_alloc_phandle(void *fdt);
>> int qemu_fdt_nop_node(void *fdt, const char *node_path);
>> int qemu_fdt_add_subnode(void *fdt, const char *name);
>> +int qemu_fdt_add_path(void *fdt, const char *path);
>>
>> #define qemu_fdt_setprop_cells(fdt, node_path, property, ...) \
>> do { \
>> diff --git a/softmmu/device_tree.c b/softmmu/device_tree.c
>> index 2691c58cf6..8592c7aa1b 100644
>> --- a/softmmu/device_tree.c
>> +++ b/softmmu/device_tree.c
>> @@ -541,8 +541,8 @@ int qemu_fdt_add_subnode(void *fdt, const char *name)
>>
>> retval = fdt_add_subnode(fdt, parent, basename);
>> if (retval < 0) {
>> - error_report("FDT: Failed to create subnode %s: %s", name,
>> - fdt_strerror(retval));
>> + error_report("%s: Failed to create subnode %s: %s",
>> + __func__, name, fdt_strerror(retval));
>> exit(1);
>> }
>>
>> @@ -550,6 +550,47 @@ int qemu_fdt_add_subnode(void *fdt, const char *name)
>> return retval;
>> }
>>
>> +/*
>> + * Like qemu_fdt_add_subnode(), but will add all missing
>> + * subnodes in the path.
>> + */
>> +int qemu_fdt_add_path(void *fdt, const char *path)
>> +{
>> + char *dupname, *basename, *p;
>> + int parent, retval = -1;
>> +
>> + if (path[0] != '/') {
>> + return retval;
>> + }
>> +
>> + parent = fdt_path_offset(fdt, "/");
> Getting the offset for "/" is never needed - it's always 0.
Thanks, will fix it.
>> + p = dupname = g_strdup(path);
> You shouldn't need the strdup(), see below.
>
>> +
>> + while (p) {
>> + *p = '/';
>> + basename = p + 1;
>> + p = strchr(p + 1, '/');
>> + if (p) {
>> + *p = '\0';
>> + }
>> + retval = fdt_path_offset(fdt, dupname);
> The fdt_path_offset_namelen() function exists *exactly* so that you
> can look up partial parths without having to mangle your input
> string. Just set the namelen right, and it will ignore anything to
> the right of that.
Function fdt_path_offset_namelen() seems more reasonable.
After we call qemu_fdt_add_path() to add "/cpus/cpu-map/socket0/core0"
successfully,
if we want to add another path like "/cpus/cpu-map/socket0/core1" we
will get the error
-FDT_ERR_NOTFOUND for each partial path. But actually
"/cpus/cpu-map/socket0"
already exists, so by using fdt_path_offset_namelen() with right namelen
we can avoid
the error retval for this part.
>> + if (retval < 0 && retval != -FDT_ERR_NOTFOUND) {
>> + error_report("%s: Invalid path %s: %s",
>> + __func__, path, fdt_strerror(retval));
> If you're getting an error other than FDT_ERR_NOTFOUND here, chances
> are it's not an invalid path, but a corrupted fdt blob or something
> else.
Right, there can be variable reasons for the fail in addition to the
invalid path.
>> + exit(1);
>> + } else if (retval == -FDT_ERR_NOTFOUND) {
>> + retval = fdt_add_subnode(fdt, parent, basename);
>> + if (retval < 0) {
>> + break;
>> + }
I found another question here. If path "/cpus/cpu-map/socket0/core0" has
already
been added, when we want to add another path "/cpus/cpu-map/socket0/core1"
and go here with retval = fdt_add_subnode(fdt, parent, "cpus"), then
retval will
be -FDT_ERR_EXISTS, but we can't just break the loop in this case.
Am I right of the explanation ?
Thanks,
Yanan
>> + }
>> + parent = retval;
>> + }
>> +
>> + g_free(dupname);
>> + return retval;
>> +}
>> +
>> void qemu_fdt_dumpdtb(void *fdt, int size)
>> {
>> const char *dumpdtb = current_machine->dumpdtb;
next prev parent reply other threads:[~2021-04-17 2:37 UTC|newest]
Thread overview: 48+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-04-13 8:07 [RFC PATCH v2 0/6] hw/arm/virt: Introduce cpu topology support Yanan Wang
2021-04-13 8:07 ` [RFC PATCH v2 1/6] device_tree: Add qemu_fdt_add_path Yanan Wang
2021-04-16 4:52 ` David Gibson
2021-04-17 2:36 ` wangyanan (Y) [this message]
2021-04-19 1:13 ` David Gibson
2021-04-19 7:02 ` wangyanan (Y)
2021-04-13 8:07 ` [RFC PATCH v2 2/6] hw/arm/virt: DT: Add cpu-map Yanan Wang
2021-04-27 9:47 ` Philippe Mathieu-Daudé
2021-04-27 10:04 ` Andrew Jones
2021-04-27 12:36 ` Philippe Mathieu-Daudé
2021-04-28 6:36 ` wangyanan (Y)
2021-05-13 6:58 ` Andrew Jones
2021-05-13 7:15 ` wangyanan (Y)
2021-04-13 8:07 ` [RFC PATCH v2 3/6] hw/arm/virt-acpi-build: Distinguish possible and present cpus Yanan Wang
2021-04-27 13:18 ` Andrew Jones
2021-04-28 6:42 ` wangyanan (Y)
2021-04-27 14:50 ` Andrew Jones
2021-04-28 6:47 ` wangyanan (Y)
2021-04-13 8:07 ` [RFC PATCH v2 4/6] hw/acpi/aml-build: Add processor hierarchy node structure Yanan Wang
2021-04-27 13:37 ` Andrew Jones
2021-04-28 6:59 ` wangyanan (Y)
2021-04-13 8:07 ` [RFC PATCH v2 5/6] hw/arm/virt-acpi-build: Add PPTT table Yanan Wang
2021-04-27 14:16 ` Andrew Jones
2021-04-28 7:30 ` wangyanan (Y)
2021-05-13 5:10 ` wangyanan (Y)
2021-05-13 6:55 ` Andrew Jones
2021-05-18 7:17 ` Salil Mehta
2021-05-18 7:42 ` Andrew Jones
2021-05-18 18:34 ` Salil Mehta
2021-05-18 19:05 ` Andrew Jones
2021-05-18 19:22 ` Salil Mehta
2021-05-19 3:18 ` wangyanan (Y)
2021-05-19 7:54 ` Salil Mehta
2021-05-19 8:15 ` Andrew Jones
2021-05-19 8:42 ` wangyanan (Y)
2021-05-19 10:00 ` Salil Mehta
2021-05-19 8:27 ` Andrew Jones
2021-05-19 13:26 ` wangyanan (Y)
2021-05-19 13:40 ` wangyanan (Y)
2021-05-18 9:16 ` wangyanan (Y)
2021-04-13 8:07 ` [RFC PATCH v2 6/6] hw/arm/virt: Replace smp_parse with one that prefers cores Yanan Wang
2021-04-27 14:58 ` Andrew Jones
2021-04-28 8:04 ` wangyanan (Y)
2021-04-28 9:36 ` wangyanan (Y)
2021-04-28 10:13 ` Andrew Jones
2021-04-29 2:21 ` wangyanan (Y)
2021-04-21 7:40 ` [RFC PATCH v2 0/6] hw/arm/virt: Introduce cpu topology support wangyanan (Y)
2021-04-21 9:31 ` wangyanan (Y)
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