[RFC] dtc: Optionally sort nodes and properties
Grant Likely
grant.likely at secretlab.ca
Thu Sep 9 06:25:30 EST 2010
On Wed, Sep 01, 2010 at 12:47:18PM +1000, David Gibson wrote:
> Hi folks,
>
> Here's a patch I made for dtc a little while ago, and I'm not sure if
> it's something that sensibly ought to be merged into mainline dtc.
>
> The patch adds a '-s' option to dtc, which causes it to "sort" the
> tree before output. That is, it sorts the reserve entries, it sorts
> the properties within each node by name, and it sorts nodes by name
> within their parent.
>
> The main use for this is when looking at the differences between two
> device trees which are similar, except for semantically null internal
> rearrangements. Directly diffing the dts files will give a lot of
> noise due to the order changes, but running both trees through dtc -s
> then diffing will usually give a pretty sensible summary of the
> changes (it can still be confused by node name changes, of course).
As discussed on IRC, I'm not thrilled with adding this as a
user-visible option because sorted trees aren't actually useful or
desirable (and in some cases undesireable) except for the use-case of
comparing trees. However, being able to compare unsorted trees is
still a use case that is very much needed, so I'm okay with this patch
until we come up with something better.
Although maybe the -s option should remain undocumented; or at least
warn people away from using it.
g.
>
> Index: dtc/dtc.c
> ===================================================================
> --- dtc.orig/dtc.c 2010-08-30 12:55:18.209765942 +1000
> +++ dtc/dtc.c 2010-08-30 14:03:46.457785218 +1000
> @@ -81,6 +81,8 @@ static void __attribute__ ((noreturn))
> fprintf(stderr, "\t\tSet the physical boot cpu\n");
> fprintf(stderr, "\t-f\n");
> fprintf(stderr, "\t\tForce - try to produce output even if the input tree has errors\n");
> + fprintf(stderr, "\t-s\n");
> + fprintf(stderr, "\t\tSort nodes and properties before outputting\n");
> fprintf(stderr, "\t-v\n");
> fprintf(stderr, "\t\tPrint DTC version and exit\n");
> fprintf(stderr, "\t-H <phandle format>\n");
> @@ -97,7 +99,7 @@ int main(int argc, char *argv[])
> const char *inform = "dts";
> const char *outform = "dts";
> const char *outname = "-";
> - int force = 0, check = 0;
> + int force = 0, check = 0, sort = 0;
> const char *arg;
> int opt;
> FILE *outf = NULL;
> @@ -109,7 +111,7 @@ int main(int argc, char *argv[])
> minsize = 0;
> padsize = 0;
>
> - while ((opt = getopt(argc, argv, "hI:O:o:V:R:S:p:fcqb:vH:")) != EOF) {
> + while ((opt = getopt(argc, argv, "hI:O:o:V:R:S:p:fcqb:vH:s")) != EOF) {
> switch (opt) {
> case 'I':
> inform = optarg;
> @@ -159,6 +161,10 @@ int main(int argc, char *argv[])
> optarg);
> break;
>
> + case 's':
> + sort = 1;
> + break;
> +
> case 'h':
> default:
> usage();
> @@ -197,6 +203,8 @@ int main(int argc, char *argv[])
> fill_fullpaths(bi->dt, "");
> process_checks(force, bi);
>
> + if (sort)
> + sort_tree(bi);
>
> if (streq(outname, "-")) {
> outf = stdout;
> Index: dtc/dtc.h
> ===================================================================
> --- dtc.orig/dtc.h 2010-08-30 13:55:02.577766011 +1000
> +++ dtc/dtc.h 2010-08-30 14:03:46.457785218 +1000
> @@ -223,6 +223,7 @@ struct boot_info {
>
> struct boot_info *build_boot_info(struct reserve_info *reservelist,
> struct node *tree, uint32_t boot_cpuid_phys);
> +void sort_tree(struct boot_info *bi);
>
> /* Checks */
>
> Index: dtc/livetree.c
> ===================================================================
> --- dtc.orig/livetree.c 2010-08-30 13:55:02.577766011 +1000
> +++ dtc/livetree.c 2010-08-30 14:03:46.461763776 +1000
> @@ -505,3 +505,140 @@ uint32_t guess_boot_cpuid(struct node *t
>
> return propval_cell(reg);
> }
> +
> +static int cmp_reserve_info(const void *ax, const void *bx)
> +{
> + const struct reserve_info *a, *b;
> +
> + a = *((const struct reserve_info * const *)ax);
> + b = *((const struct reserve_info * const *)bx);
> +
> + if (a->re.address < b->re.address)
> + return -1;
> + else if (a->re.address > b->re.address)
> + return 1;
> + else if (a->re.size < b->re.size)
> + return -1;
> + else if (a->re.size > b->re.size)
> + return 1;
> + else
> + return 0;
> +}
> +
> +static void sort_reserve_entries(struct boot_info *bi)
> +{
> + struct reserve_info *ri, **tbl;
> + int n = 0, i = 0;
> +
> + for (ri = bi->reservelist;
> + ri;
> + ri = ri->next)
> + n++;
> +
> + if (n == 0)
> + return;
> +
> + tbl = xmalloc(n * sizeof(*tbl));
> +
> + for (ri = bi->reservelist;
> + ri;
> + ri = ri->next)
> + tbl[i++] = ri;
> +
> + qsort(tbl, n, sizeof(*tbl), cmp_reserve_info);
> +
> + bi->reservelist = tbl[0];
> + for (i = 0; i < (n-1); i++)
> + tbl[i]->next = tbl[i+1];
> + tbl[n-1]->next = NULL;
> +
> + free(tbl);
> +}
> +
> +static int cmp_prop(const void *ax, const void *bx)
> +{
> + const struct property *a, *b;
> +
> + a = *((const struct property * const *)ax);
> + b = *((const struct property * const *)bx);
> +
> + return strcmp(a->name, b->name);
> +}
> +
> +static void sort_properties(struct node *node)
> +{
> + int n = 0, i = 0;
> + struct property *prop, **tbl;
> +
> + for_each_property(node, prop)
> + n++;
> +
> + if (n == 0)
> + return;
> +
> + tbl = xmalloc(n * sizeof(*tbl));
> +
> + for_each_property(node, prop)
> + tbl[i++] = prop;
> +
> + qsort(tbl, n, sizeof(*tbl), cmp_prop);
> +
> + node->proplist = tbl[0];
> + for (i = 0; i < (n-1); i++)
> + tbl[i]->next = tbl[i+1];
> + tbl[n-1]->next = NULL;
> +
> + free(tbl);
> +}
> +
> +static int cmp_subnode(const void *ax, const void *bx)
> +{
> + const struct node *a, *b;
> +
> + a = *((const struct node * const *)ax);
> + b = *((const struct node * const *)bx);
> +
> + return strcmp(a->name, b->name);
> +}
> +
> +static void sort_subnodes(struct node *node)
> +{
> + int n = 0, i = 0;
> + struct node *subnode, **tbl;
> +
> + for_each_child(node, subnode)
> + n++;
> +
> + if (n == 0)
> + return;
> +
> + tbl = xmalloc(n * sizeof(*tbl));
> +
> + for_each_child(node, subnode)
> + tbl[i++] = subnode;
> +
> + qsort(tbl, n, sizeof(*tbl), cmp_subnode);
> +
> + node->children = tbl[0];
> + for (i = 0; i < (n-1); i++)
> + tbl[i]->next_sibling = tbl[i+1];
> + tbl[n-1]->next_sibling = NULL;
> +
> + free(tbl);
> +}
> +
> +static void sort_node(struct node *node)
> +{
> + struct node *c;
> +
> + sort_properties(node);
> + sort_subnodes(node);
> + for_each_child(node, c)
> + sort_node(c);
> +}
> +
> +void sort_tree(struct boot_info *bi)
> +{
> + sort_reserve_entries(bi);
> + sort_node(bi->dt);
> +}
> Index: dtc/tests/run_tests.sh
> ===================================================================
> --- dtc.orig/tests/run_tests.sh 2010-08-30 14:03:42.218764527 +1000
> +++ dtc/tests/run_tests.sh 2010-08-30 14:03:46.461763776 +1000
> @@ -377,6 +377,13 @@ cmp_tests () {
> for tree in $wrongtrees; do
> run_test dtbs_equal_unordered -n $basetree $tree
> done
> +
> + # now dtc --sort
> + run_dtc_test -I dtb -O dtb -s -o $basetree.sorted.test.dtb $basetree
> + run_test dtbs_equal_unordered $basetree $basetree.sorted.test.dtb
> + run_dtc_test -I dtb -O dtb -s -o $basetree.reversed.sorted.test.dtb $basetree.reversed.test.dtb
> + run_test dtbs_equal_unordered $basetree.reversed.test.dtb $basetree.reversed.sorted.test.dtb
> + run_test dtbs_equal_ordered $basetree.sorted.test.dtb $basetree.reversed.sorted.test.dtb
> }
>
> dtbs_equal_tests () {
>
>
>
> --
> David Gibson | I'll have my music baroque, and my code
> david AT gibson.dropbear.id.au | minimalist, thank you. NOT _the_ _other_
> | _way_ _around_!
> http://www.ozlabs.org/~dgibson
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