[PATCH v3 1/2] fdt: Add fdtdec_find_aliases() to deal with alias nodes

[PATCH v3 1/2] fdt: Add fdtdec_find_aliases() to deal with alias nodes

[Simon Glass]

Stephen Warren pointed out that we should use nodes whether or not they
have an alias in the /aliases section. The aliases section specifies the
order so far as it can, but is not essential. Operating without alisses
is useful when the enumerated order of nodes does not matter (admittedly
rare in U-Boot).

This is considerably more complex, and it is important to keep this
complexity out of driver code. This patch creates a function
fdtdec_find_aliases() which returns an ordered list of node offsets
for a particular compatible ID, taking account of alias nodes.

Signed-off-by: Simon Glass <sjg@chromium.org>
---
Changes in v2:
- Allow gaps in the list returned to the caller
- Improve alias checking algorithm to reduce run time
- Rename function to fdtdec_find_aliases_for_id()
- Skip nodes marked as disabled

Changes in v3:
- Change 'continue' to 'break' in last loop, since we are done anyway
- Fix typos and add two assert() checks

 include/fdtdec.h |   47 ++++++++++++++++++++++
 lib/fdtdec.c     |  116 ++++++++++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 163 insertions(+), 0 deletions(-)

diff --git a/include/fdtdec.h b/include/fdtdec.h
index d871cdd..492431c 100644
--- a/include/fdtdec.h
+++ b/include/fdtdec.h
@@ -126,3 +126,50 @@ int fdtdec_get_is_enabled(const void *blob, int node, int default_val);
  * if not.
  */
 int fdtdec_check_fdt(void);
+
+/**
+ * Find the nodes for a peripheral and return a list of them in the correct
+ * order. This is used to enumerate all the peripherals of a certain type.
+ *
+ * To use this, optionally set up a /aliases node with alias properties for
+ * a peripheral. For example, for usb you could have:
+ *
+ * aliases {
+ *		usb0 = "/ehci@c5008000";
+ *		usb1 = "/ehci@c5000000";
+ * };
+ *
+ * Pass "usb" as the name to this function and will return a list of two
+ * nodes offsets: /ehci@c5008000 and ehci@c5000000.
+ *
+ * All nodes returned will match the compatible ID, as it is assumed that
+ * all peripherals use the same driver.
+ *
+ * If no alias node is found, then the node list will be returned in the
+ * order found in the fdt. If the aliases mention a node which doesn't
+ * exist, then this will be ignored. If nodes are found with no aliases,
+ * they will be added in any order.
+ *
+ * If there is a gap in the aliases, then this function return a 0 node at
+ * that position. The return value will also count these gaps.
+ *
+ * This function checks node properties and will not return nodes which are
+ * marked disabled (status = "disabled").
+ *
+ * @param blob		FDT blob to use
+ * @param name		Root name of alias to search for
+ * @param id		Compatible ID to look for
+ * @param node_list	Place to put list of found nodes
+ * @param maxcount	Maximum number of nodes to find
+ * @return number of nodes found on success, FTD_ERR_... on error
+ */
+int fdtdec_find_aliases_for_id(const void *blob, const char *name,
+			enum fdt_compat_id id, int *node_list, int maxcount);
+
+/*
+ * Get the name for a compatible ID
+ *
+ * @param id		Compatible ID to look for
+ * @return compatible string for that id
+ */
+const char *fdtdec_get_compatible(enum fdt_compat_id id);
diff --git a/lib/fdtdec.c b/lib/fdtdec.c
index 0f87163..55d5bdf 100644
--- a/lib/fdtdec.c
+++ b/lib/fdtdec.c
@@ -35,6 +35,13 @@ DECLARE_GLOBAL_DATA_PTR;
 static const char * const compat_names[COMPAT_COUNT] = {
 };
 
+const char *fdtdec_get_compatible(enum fdt_compat_id id)
+{
+	/* We allow reading of the 'unknown' ID for testing purposes */
+	assert(id >= 0 && id < COMPAT_COUNT);
+	return compat_names[id];
+}
+
 /**
  * Look in the FDT for an alias with the given name and return its node.
  *
@@ -132,6 +139,115 @@ int fdtdec_next_alias(const void *blob, const char *name,
 	return err ? -FDT_ERR_NOTFOUND : node;
 }
 
+/* TODO: Can we tighten this code up a little? */
+int fdtdec_find_aliases_for_id(const void *blob, const char *name,
+			enum fdt_compat_id id, int *node_list, int maxcount)
+{
+	int name_len = strlen(name);
+	int nodes[maxcount];
+	int num_found = 0;
+	int offset, node;
+	int alias_node;
+	int count;
+	int i, j;
+
+	/* find the alias node if present */
+	alias_node = fdt_path_offset(blob, "/aliases");
+
+	/*
+	 * start with nothing, and we can assume that the root node can't
+	 * match
+	 */
+	memset(nodes, '\0', sizeof(nodes));
+
+	/* First find all the compatible nodes */
+	for (node = count = 0; node >= 0 && count < maxcount;) {
+		node = fdtdec_next_compatible(blob, node, id);
+		if (node >= 0)
+			nodes[count++] = node;
+	}
+	if (node >= 0)
+		debug("%s: warning: maxcount exceeded with alias '%s'\n",
+		       __func__, name);
+
+	/* Now find all the aliases */
+	memset(node_list, '\0', sizeof(*node_list) * maxcount);
+
+	for (offset = fdt_first_property_offset(blob, alias_node);
+			offset > 0;
+			offset = fdt_next_property_offset(blob, offset)) {
+		const struct fdt_property *prop;
+		const char *path;
+		int number;
+		int found;
+
+		node = 0;
+		prop = fdt_get_property_by_offset(blob, offset, NULL);
+		path = fdt_string(blob, fdt32_to_cpu(prop->nameoff));
+		if (prop->len && 0 == strncmp(path, name, name_len))
+			node = fdt_path_offset(blob, prop->data);
+		if (node <= 0)
+			continue;
+
+		/* Get the alias number */
+		number = simple_strtoul(path + name_len, NULL, 10);
+		if (number < 0 || number >= maxcount) {
+			debug("%s: warning: alias '%s' is out of range\n",
+			       __func__, path);
+			continue;
+		}
+
+		/* Make sure the node we found is actually in our list! */
+		found = -1;
+		for (j = 0; j < count; j++)
+			if (nodes[j] == node) {
+				found = j;
+				break;
+			}
+
+		if (found == -1) {
+			debug("%s: warning: alias '%s' points to a node "
+				"'%s' that is missing or is not compatible "
+				" with '%s'\n", __func__, path,
+				fdt_get_name(blob, node, NULL),
+			       compat_names[id]);
+			continue;
+		}
+
+		/*
+		 * Add this node to our list in the right place, and mark
+		 * it as done.
+		 */
+		if (fdtdec_get_is_enabled(blob, node)) {
+			node_list[number] = node;
+			if (number >= num_found)
+				num_found = number + 1;
+		}
+		nodes[j] = 0;
+	}
+
+	/* Add any nodes not mentioned by an alias */
+	for (i = j = 0; i < maxcount; i++) {
+		if (!node_list[i]) {
+			for (; j < maxcount; j++)
+				if (nodes[j] &&
+					fdtdec_get_is_enabled(blob, nodes[j]))
+					break;
+
+			/* Have we run out of nodes to add? */
+			if (j == maxcount)
+				break;
+
+			assert(!node_list[i]);
+			node_list[i] = nodes[j++];
+			if (i >= num_found)
+				num_found = i + 1;
+		}
+	}
+
+	return num_found;
+}
+
 /*
  * This function is a little odd in that it accesses global data. At some
  * point if the architecture board.c files merge this will make more sense.
-- 
1.7.7.3

Re: [U-Boot] [PATCH v3 1/2] fdt: Add fdtdec_find_aliases() to deal with alias nodes

[Jerry Van Baren]

On 01/17/2012 01:20 PM, Simon Glass wrote:
> Stephen Warren pointed out that we should use nodes whether or not they
> have an alias in the /aliases section. The aliases section specifies the
> order so far as it can, but is not essential. Operating without alisses

Nitpick: aliases

> is useful when the enumerated order of nodes does not matter (admittedly
> rare in U-Boot).
> 
> This is considerably more complex, and it is important to keep this
> complexity out of driver code. This patch creates a function
> fdtdec_find_aliases() which returns an ordered list of node offsets
> for a particular compatible ID, taking account of alias nodes.
> 
> Signed-off-by: Simon Glass<sjg-F7+t8E8rja9g9hUCZPvPmw@public.gmane.org>

Acked-by: Gerald Van Baren <vanbaren-He//nVnquyzQT0dZR+AlfA@public.gmane.org>

Thanks,
gvb

Re: [PATCH v3 1/2] fdt: Add fdtdec_find_aliases() to deal with alias nodes

[Simon Glass]

Hi Jerry,

On Sun, Jan 22, 2012 at 6:04 PM, Jerry Van Baren <gvb.uboot@gmail.com> wrote:
> On 01/17/2012 01:20 PM, Simon Glass wrote:
>> Stephen Warren pointed out that we should use nodes whether or not they
>> have an alias in the /aliases section. The aliases section specifies the
>> order so far as it can, but is not essential. Operating without alisses
>
> Nitpick: aliases

Thanks for the review - will resend this patch to tidy that up.

>
>> is useful when the enumerated order of nodes does not matter (admittedly
>> rare in U-Boot).
>>
>> This is considerably more complex, and it is important to keep this
>> complexity out of driver code. This patch creates a function
>> fdtdec_find_aliases() which returns an ordered list of node offsets
>> for a particular compatible ID, taking account of alias nodes.
>>
>> Signed-off-by: Simon Glass<sjg@chromium.org>
>
> Acked-by: Gerald Van Baren <vanbaren@cideas.com>
>
> Thanks,
> gvb

Regards,
Simon

[PATCH v3 2/2] fdt: Add tests for fdtdec

[Simon Glass]

The fdtdec_find_aliases_for_id() function is complicated enough that
it really should have some tests. This does not necessarily need to be
committed to U-Boot, but it might be useful.

(note there are a few minor inconsistencies with this patch which will be
cleaned up when the USB series is applied)

Signed-off-by: Simon Glass <sjg-F7+t8E8rja9g9hUCZPvPmw@public.gmane.org>
---
Changes in v2:
- Add test_fdtdec command to test fdtdec_find_aliases_for_id()

Changes in v3:
- Change fdtdec-test.c to fdtdec_test.c to fit better with U-Boot conventions
- Remove varargs declaration (hang-over from previous implementation)
- Use COMPAT_UNKNOWN instead of COMPAT_NVIDIA_TEGRA20_I2C for test

 lib/Makefile      |    1 +
 lib/fdtdec_test.c |  226 +++++++++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 227 insertions(+), 0 deletions(-)
 create mode 100644 lib/fdtdec_test.c

diff --git a/lib/Makefile b/lib/Makefile
index 35ba7ff..b938549 100644
--- a/lib/Makefile
+++ b/lib/Makefile
@@ -39,6 +39,7 @@ COBJS-y += crc32.o
 COBJS-y += display_options.o
 COBJS-y += errno.o
 COBJS-$(CONFIG_OF_CONTROL) += fdtdec.o
+COBJS-$(CONFIG_TEST_FDTDEC) += fdtdec_test.o
 COBJS-$(CONFIG_GZIP) += gunzip.o
 COBJS-y += hashtable.o
 COBJS-$(CONFIG_LMB) += lmb.o
diff --git a/lib/fdtdec_test.c b/lib/fdtdec_test.c
new file mode 100644
index 0000000..497be8e
--- /dev/null
+++ b/lib/fdtdec_test.c
@@ -0,0 +1,226 @@
+/*
+ * Some very basic tests for fdtdec, accessed through test_fdtdec command.
+ * They are easiest to use with sandbox.
+ *
+ * Copyright (c) 2011 The Chromium OS Authors.
+ * See file CREDITS for list of people who contributed to this
+ * project.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation; either version 2 of
+ * the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
+ * MA 02111-1307 USA
+ */
+
+#include <common.h>
+#include <fdtdec.h>
+#include <libfdt.h>
+#include <malloc.h>
+#include <os.h>
+
+/* The size of our test fdt blob */
+#define FDT_SIZE	(16 * 1024)
+
+/**
+ * Check if an operation failed, and if so, print an error
+ *
+ * @param oper_name	Name of operation
+ * @param err		Error code to check
+ *
+ * @return 0 if ok, -1 if there was an error
+ */
+static int fdt_checkerr(const char *oper_name, int err)
+{
+	if (err) {
+		printf("%s: %s: %s\n", __func__, oper_name, fdt_strerror(err));
+		return -1;
+	}
+
+	return 0;
+}
+
+/**
+ * Check the result of an operation and if incorrect, print an error
+ *
+ * @param oper_name	Name of operation
+ * @param expected	Expected value
+ * @param value		Actual value
+ *
+ * @return 0 if ok, -1 if there was an error
+ */
+static int checkval(const char *oper_name, int expected, int value)
+{
+	if (expected != value) {
+		printf("%s: %s: expected %d, but returned %d\n", __func__,
+		       oper_name, expected, value);
+		return -1;
+	}
+
+	return 0;
+}
+
+#define CHECK(op)	if (fdt_checkerr(#op, op)) return -1
+#define CHECKVAL(op, expected)	\
+	if (checkval(#op, expected, op)) \
+		return -1
+#define CHECKOK(op)	CHECKVAL(op, 0)
+
+/* maximum number of nodes / aliases to generate */
+#define MAX_NODES	20
+
+/*
+ * Make a test fdt
+ *
+ * @param fdt		Device tree pointer
+ * @param size		Size of device tree blob
+ * @param aliases	Specifies alias assignments. Format is a list of items
+ *			separated by space. Items are #a where
+ *				# is the alias number
+ *				a is the node to point to
+ * @param nodes		Specifies nodes to generate (a=0, b=1), upper case
+ *			means to create a disabled node
+ */
+static int make_fdt(void *fdt, int size, const char *aliases,
+		    const char *nodes)
+{
+	char name[20], value[20];
+	const char *s;
+	int fd;
+
+	CHECK(fdt_create(fdt, size));
+	CHECK(fdt_finish_reservemap(fdt));
+	CHECK(fdt_begin_node(fdt, ""));
+
+	CHECK(fdt_begin_node(fdt, "aliases"));
+	for (s = aliases; *s;) {
+		sprintf(name, "i2c%c", *s);
+		sprintf(value, "/i2c%d@0", s[1] - 'a');
+		CHECK(fdt_property_string(fdt, name, value));
+		s += 2 + (s[2] != '\0');
+	}
+	CHECK(fdt_end_node(fdt));
+
+	for (s = nodes; *s; s++) {
+		sprintf(value, "i2c%d@0", (*s & 0xdf) - 'A');
+		CHECK(fdt_begin_node(fdt, value));
+		CHECK(fdt_property_string(fdt, "compatible",
+			fdtdec_get_compatible(COMPAT_UNKNOWN)));
+		if (*s <= 'Z')
+			CHECK(fdt_property_string(fdt, "status", "disabled"));
+		CHECK(fdt_end_node(fdt));
+	}
+
+	CHECK(fdt_end_node(fdt));
+	CHECK(fdt_finish(fdt));
+	CHECK(fdt_pack(fdt));
+#if defined(DEBUG) && defined(CONFIG_SANDBOX)
+	fd = os_open("/tmp/fdtdec-text.dtb", OS_O_CREAT | OS_O_WRONLY);
+	if (fd == -1) {
+		printf("Could not open .dtb file to write\n");
+		return -1;
+	}
+	os_write(fd, fdt, size);
+	os_close(fd);
+#endif
+	return 0;
+}
+
+static int run_test(const char *aliases, const char *nodes, const char *expect)
+{
+	int list[MAX_NODES];
+	const char *s;
+	void *blob;
+	int i;
+
+	blob = malloc(FDT_SIZE);
+	if (!blob) {
+		printf("%s: out of memory\n", __func__);
+		return 1;
+	}
+
+	printf("aliases=%s, nodes=%s, expect=%s: ", aliases, nodes, expect);
+	CHECKVAL(make_fdt(blob, FDT_SIZE, aliases, nodes), 0);
+	CHECKVAL(fdtdec_find_aliases_for_id(blob, "i2c",
+			COMPAT_UNKNOWN,
+			list, ARRAY_SIZE(list)), strlen(expect));
+
+	/* Check we got the right ones */
+	for (i = 0, s = expect; *s; s++, i++) {
+		int want = *s;
+		const char *name;
+		int got = ' ';
+
+		name = list[i] ? fdt_get_name(blob, list[i], NULL) : NULL;
+		if (name)
+			got = name[3] + 'a' - '0';
+
+		if (got != want) {
+			printf("Position %d: Expected '%c', got '%c' ('%s')\n",
+			       i, want, got, name);
+			return 1;
+		}
+	}
+
+	printf("pass\n");
+	return 0;
+}
+
+static int do_test_fdtdec(cmd_tbl_t *cmdtp, int flag, int argc,
+			  char * const argv[])
+{
+	/* basic tests */
+	CHECKOK(run_test("", "", ""));
+	CHECKOK(run_test("1e 3d", "", ""));
+
+	/*
+	 * 'a' represents 0, 'b' represents 1, etc.
+	 * The first character is the alias number, the second is the node
+	 * number. So the params mean:
+	 * 0a 1b	: point alias 0 to node 0 (a), alias 1 to node 1(b)
+	 * ab		: to create nodes 0 and 1 (a and b)
+	 * ab		: we expect the function to return two nodes, in
+	 *		  the order 0, 1
+	 */
+	CHECKOK(run_test("0a 1b", "ab", "ab"));
+
+	CHECKOK(run_test("0a 1c", "ab", "ab"));
+	CHECKOK(run_test("1c", "ab", "ab"));
+	CHECKOK(run_test("1b", "ab", "ab"));
+	CHECKOK(run_test("0b", "ab", "ba"));
+	CHECKOK(run_test("0b 2d", "dbc", "bcd"));
+	CHECKOK(run_test("0d 3a 1c 2b", "dbac", "dcba"));
+
+	/* things with holes */
+	CHECKOK(run_test("1b 3d", "dbc", "cb d"));
+	CHECKOK(run_test("1e 3d", "dbc", "bc d"));
+
+	/* no aliases */
+	CHECKOK(run_test("", "dbac", "dbac"));
+
+	/* disabled nodes */
+	CHECKOK(run_test("0d 3a 1c 2b", "dBac", "dc a"));
+	CHECKOK(run_test("0b 2d", "DBc", "c"));
+	CHECKOK(run_test("0b 4d 2c", "DBc", "  c"));
+
+	/* conflicting aliases - first one gets it */
+	CHECKOK(run_test("2a 1a 0a", "a", "  a"));
+	CHECKOK(run_test("0a 1a 2a", "a", "a"));
+
+	printf("Test passed\n");
+	return 0;
+}
+
+U_BOOT_CMD(
+	test_fdtdec, 3, 1, do_test_fdtdec,
+	"test_fdtdec",
+	"Run tests for fdtdec library");
-- 
1.7.7.3

Re: [U-Boot] [PATCH v3 2/2] fdt: Add tests for fdtdec

[Jerry Van Baren]

On 01/17/2012 01:20 PM, Simon Glass wrote:
> The fdtdec_find_aliases_for_id() function is complicated enough that
> it really should have some tests. This does not necessarily need to be
> committed to U-Boot, but it might be useful.
> 
> (note there are a few minor inconsistencies with this patch which will be
> cleaned up when the USB series is applied)
> 
> Signed-off-by: Simon Glass<sjg-F7+t8E8rja9g9hUCZPvPmw@public.gmane.org>

Acked-by: Gerald Van Baren <vanbaren-He//nVnquyzQT0dZR+AlfA@public.gmane.org>

Thanks,
gvb