| Message ID | 1454334712-12360-3-git-send-email-eric.auger@linaro.org |
|---|---|
| State | New |
| Headers | show |
On Mon, Feb 1, 2016 at 7:51 AM, Eric Auger <eric.auger@linaro.org> 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 <eric.auger@linaro.org> > > --- > 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. Rob
Hi Rob, On 02/01/2016 05:15 PM, Rob Herring wrote: > On Mon, Feb 1, 2016 at 7:51 AM, Eric Auger <eric.auger@linaro.org> 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 <eric.auger@linaro.org> >> >> --- >> 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. Thank you in advance Best Regards Eric > > Rob >
On Mon, Feb 1, 2016 at 10:22 AM, Eric Auger <eric.auger@linaro.org> wrote: > Hi Rob, > On 02/01/2016 05:15 PM, Rob Herring wrote: >> On Mon, Feb 1, 2016 at 7:51 AM, Eric Auger <eric.auger@linaro.org> 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 <eric.auger@linaro.org> >>> >>> --- >>> 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. Rob
On 02/01/2016 05:27 PM, Rob Herring wrote: > On Mon, Feb 1, 2016 at 10:22 AM, Eric Auger <eric.auger@linaro.org> wrote: >> Hi Rob, >> On 02/01/2016 05:15 PM, Rob Herring wrote: >>> On Mon, Feb 1, 2016 at 7:51 AM, Eric Auger <eric.auger@linaro.org> 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 <eric.auger@linaro.org> >>>> >>>> --- >>>> 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 >
On 1 February 2016 at 13:51, Eric Auger <eric.auger@linaro.org> 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 <eric.auger@linaro.org> Reviewed-by: Peter Maydell <peter.maydell@linaro.org> thanks -- PMM
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" + +/** + * read_fstree: this function is inspired from dtc read_fstree + * @fdt: preallocated fdt blob buffer, to be populated + * @dirname: directory to scan under SYSFS_DT_BASEDIR + * the search is recursive and the tree is searched down to the + * leaves (property files). + * + * the function asserts in case of error + */ +static void read_fstree(void *fdt, const char *dirname) +{ + DIR *d; + struct dirent *de; + struct stat st; + const char *root_dir = SYSFS_DT_BASEDIR; + const char *parent_node; + + if (strstr(dirname, root_dir) != dirname) { + error_setg(&error_fatal, "%s: %s must be searched within %s", + __func__, dirname, root_dir); + } + parent_node = &dirname[strlen(SYSFS_DT_BASEDIR)]; + + d = opendir(dirname); + if (!d) { + error_setg(&error_fatal, "%s cannot open %s", __func__, dirname); + } + + while ((de = readdir(d)) != NULL) { + char *tmpnam; + + if (!g_strcmp0(de->d_name, ".") + || !g_strcmp0(de->d_name, "..")) { + continue; + } + + tmpnam = g_strdup_printf("%s/%s", dirname, de->d_name); + + if (lstat(tmpnam, &st) < 0) { + error_setg(&error_fatal, "%s cannot lstat %s", __func__, tmpnam); + } + + if (S_ISREG(st.st_mode)) { + gchar *val; + gsize len; + + if (!g_file_get_contents(tmpnam, &val, &len, NULL)) { + error_setg(&error_fatal, "%s not able to extract info from %s", + __func__, tmpnam); + } + + if (strlen(parent_node) > 0) { + qemu_fdt_setprop(fdt, parent_node, + de->d_name, val, len); + } else { + qemu_fdt_setprop(fdt, "/", de->d_name, val, len); + } + g_free(val); + } else if (S_ISDIR(st.st_mode)) { + char *node_name; + + node_name = g_strdup_printf("%s/%s", + parent_node, de->d_name); + qemu_fdt_add_subnode(fdt, node_name); + g_free(node_name); + read_fstree(fdt, tmpnam); + } + + g_free(tmpnam); + } + + closedir(d); +} + +/* load_device_tree_from_sysfs: extract the dt blob from host sysfs */ +void *load_device_tree_from_sysfs(void) +{ + void *host_fdt; + int host_fdt_size; + + host_fdt = create_device_tree(&host_fdt_size); + read_fstree(host_fdt, SYSFS_DT_BASEDIR); + if (fdt_check_header(host_fdt)) { + error_setg(&error_fatal, + "%s host device tree extracted into memory is invalid", + __func__); + } + return host_fdt; +} + +#endif /* CONFIG_LINUX */ + static int findnode_nofail(void *fdt, const char *node_path) { int offset; diff --git a/include/sysemu/device_tree.h b/include/sysemu/device_tree.h index 359e143..62093ba 100644 --- a/include/sysemu/device_tree.h +++ b/include/sysemu/device_tree.h @@ -16,6 +16,14 @@ void *create_device_tree(int *sizep); void *load_device_tree(const char *filename_path, int *sizep); +#ifdef CONFIG_LINUX +/** + * load_device_tree_from_sysfs: reads the device tree information in the + * /proc/device-tree directory and return the corresponding binary blob + * buffer pointer. Asserts in case of error. + */ +void *load_device_tree_from_sysfs(void); +#endif int qemu_fdt_setprop(void *fdt, const char *node_path, const char *property, const void *val, int size);
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 <eric.auger@linaro.org> --- 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(+)