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https://github.com/brain-hackers/u-boot-brain
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![Simon Glass](/assets/img/avatar_default.png)
This adds some support into fdtdec for reading GPIO definitions from the fdt. We permit up to FDT_GPIO_MAX GPIOs in the system. Each GPIO is of the form: gpio-function-name = <phandle gpio_num flags>; where: phandle is a pointer to the GPIO node gpio_num is the number of the GPIO (0 to 223) flags is a flag, as follows: bit meaning 0 0=polarity normal, 1=active low (inverted) An example is: enable-propounder-gpios = <&gpio 43 0>; which means that GPIO 43 is used to enable the propounder (setting the GPIO high), or that you can detect that the propounder is enabled by checking if the GPIO is high (the fdt does not indicate input/output). Two main functions are provided: fdtdec_decode_gpio() reads a GPIO property from an fdt node and decodes it into a structure. fdtdec_setup_gpio() sets up the GPIO by calling gpio_request for you. Both functions can cope with the property being missing, which is taken to mean that that GPIO function is not available or is not needed. [For reference, from Stephen Warren <swarren@nvidia.com>. It may be that we add this extra complexity later if needed: The correct way to parse such a GPIO property in general is: * Read the first cell. * Find the node referenced by the phandle (the controller). * Ensure property gpio-controller is present in the controller node. * Read property #gpio-cells from the controller node. * Extract #gpio-cells from the original property. * Keep processing more cells from the original property; there may be multiple GPIOs listed. According to the binding documentation in the Linux kernel, Samsung Exynos4 doesn't use this format, and while all other chips do have a flags cell, about 50% of the controllers indicate the cell is unused. ] Signed-off-by: Simon Glass <sjg@chromium.org> Signed-off-by: Tom Warren <twarren@nvidia.com>
420 lines
11 KiB
C
420 lines
11 KiB
C
/*
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* Copyright (c) 2011 The Chromium OS Authors.
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* See file CREDITS for list of people who contributed to this
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* project.
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License as
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* published by the Free Software Foundation; either version 2 of
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* the License, or (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place, Suite 330, Boston,
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* MA 02111-1307 USA
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*/
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#include <common.h>
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#include <serial.h>
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#include <libfdt.h>
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#include <fdtdec.h>
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/* we need the generic GPIO interface here */
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#include <asm-generic/gpio.h>
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DECLARE_GLOBAL_DATA_PTR;
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/*
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* Here are the type we know about. One day we might allow drivers to
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* register. For now we just put them here. The COMPAT macro allows us to
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* turn this into a sparse list later, and keeps the ID with the name.
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*/
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#define COMPAT(id, name) name
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static const char * const compat_names[COMPAT_COUNT] = {
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COMPAT(UNKNOWN, "<none>"),
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};
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const char *fdtdec_get_compatible(enum fdt_compat_id id)
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{
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/* We allow reading of the 'unknown' ID for testing purposes */
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assert(id >= 0 && id < COMPAT_COUNT);
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return compat_names[id];
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}
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/**
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* Look in the FDT for an alias with the given name and return its node.
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*
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* @param blob FDT blob
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* @param name alias name to look up
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* @return node offset if found, or an error code < 0 otherwise
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*/
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static int find_alias_node(const void *blob, const char *name)
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{
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const char *path;
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int alias_node;
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debug("find_alias_node: %s\n", name);
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alias_node = fdt_path_offset(blob, "/aliases");
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if (alias_node < 0)
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return alias_node;
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path = fdt_getprop(blob, alias_node, name, NULL);
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if (!path)
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return -FDT_ERR_NOTFOUND;
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return fdt_path_offset(blob, path);
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}
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fdt_addr_t fdtdec_get_addr(const void *blob, int node,
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const char *prop_name)
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{
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const fdt_addr_t *cell;
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int len;
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debug("get_addr: %s\n", prop_name);
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cell = fdt_getprop(blob, node, prop_name, &len);
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if (cell && (len == sizeof(fdt_addr_t) ||
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len == sizeof(fdt_addr_t) * 2))
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return fdt_addr_to_cpu(*cell);
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return FDT_ADDR_T_NONE;
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}
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s32 fdtdec_get_int(const void *blob, int node, const char *prop_name,
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s32 default_val)
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{
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const s32 *cell;
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int len;
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debug("get_size: %s\n", prop_name);
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cell = fdt_getprop(blob, node, prop_name, &len);
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if (cell && len >= sizeof(s32))
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return fdt32_to_cpu(cell[0]);
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return default_val;
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}
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int fdtdec_get_is_enabled(const void *blob, int node)
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{
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const char *cell;
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/*
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* It should say "okay", so only allow that. Some fdts use "ok" but
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* this is a bug. Please fix your device tree source file. See here
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* for discussion:
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*
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* http://www.mail-archive.com/u-boot@lists.denx.de/msg71598.html
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*/
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cell = fdt_getprop(blob, node, "status", NULL);
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if (cell)
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return 0 == strcmp(cell, "okay");
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return 1;
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}
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enum fdt_compat_id fd_dec_lookup(const void *blob, int node)
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{
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enum fdt_compat_id id;
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/* Search our drivers */
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for (id = COMPAT_UNKNOWN; id < COMPAT_COUNT; id++)
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if (0 == fdt_node_check_compatible(blob, node,
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compat_names[id]))
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return id;
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return COMPAT_UNKNOWN;
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}
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int fdtdec_next_compatible(const void *blob, int node,
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enum fdt_compat_id id)
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{
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return fdt_node_offset_by_compatible(blob, node, compat_names[id]);
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}
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int fdtdec_next_alias(const void *blob, const char *name,
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enum fdt_compat_id id, int *upto)
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{
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#define MAX_STR_LEN 20
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char str[MAX_STR_LEN + 20];
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int node, err;
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/* snprintf() is not available */
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assert(strlen(name) < MAX_STR_LEN);
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sprintf(str, "%.*s%d", MAX_STR_LEN, name, *upto);
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node = find_alias_node(blob, str);
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if (node < 0)
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return node;
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err = fdt_node_check_compatible(blob, node, compat_names[id]);
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if (err < 0)
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return err;
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if (err)
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return -FDT_ERR_NOTFOUND;
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(*upto)++;
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return node;
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}
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/* TODO: Can we tighten this code up a little? */
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int fdtdec_find_aliases_for_id(const void *blob, const char *name,
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enum fdt_compat_id id, int *node_list, int maxcount)
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{
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int name_len = strlen(name);
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int nodes[maxcount];
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int num_found = 0;
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int offset, node;
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int alias_node;
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int count;
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int i, j;
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/* find the alias node if present */
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alias_node = fdt_path_offset(blob, "/aliases");
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/*
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* start with nothing, and we can assume that the root node can't
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* match
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*/
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memset(nodes, '\0', sizeof(nodes));
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/* First find all the compatible nodes */
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for (node = count = 0; node >= 0 && count < maxcount;) {
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node = fdtdec_next_compatible(blob, node, id);
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if (node >= 0)
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nodes[count++] = node;
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}
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if (node >= 0)
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debug("%s: warning: maxcount exceeded with alias '%s'\n",
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__func__, name);
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/* Now find all the aliases */
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memset(node_list, '\0', sizeof(*node_list) * maxcount);
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for (offset = fdt_first_property_offset(blob, alias_node);
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offset > 0;
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offset = fdt_next_property_offset(blob, offset)) {
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const struct fdt_property *prop;
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const char *path;
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int number;
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int found;
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node = 0;
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prop = fdt_get_property_by_offset(blob, offset, NULL);
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path = fdt_string(blob, fdt32_to_cpu(prop->nameoff));
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if (prop->len && 0 == strncmp(path, name, name_len))
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node = fdt_path_offset(blob, prop->data);
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if (node <= 0)
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continue;
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/* Get the alias number */
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number = simple_strtoul(path + name_len, NULL, 10);
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if (number < 0 || number >= maxcount) {
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debug("%s: warning: alias '%s' is out of range\n",
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__func__, path);
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continue;
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}
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/* Make sure the node we found is actually in our list! */
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found = -1;
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for (j = 0; j < count; j++)
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if (nodes[j] == node) {
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found = j;
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break;
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}
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if (found == -1) {
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debug("%s: warning: alias '%s' points to a node "
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"'%s' that is missing or is not compatible "
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" with '%s'\n", __func__, path,
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fdt_get_name(blob, node, NULL),
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compat_names[id]);
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continue;
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}
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/*
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* Add this node to our list in the right place, and mark
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* it as done.
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*/
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if (fdtdec_get_is_enabled(blob, node)) {
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node_list[number] = node;
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if (number >= num_found)
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num_found = number + 1;
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}
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nodes[j] = 0;
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}
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/* Add any nodes not mentioned by an alias */
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for (i = j = 0; i < maxcount; i++) {
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if (!node_list[i]) {
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for (; j < maxcount; j++)
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if (nodes[j] &&
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fdtdec_get_is_enabled(blob, nodes[j]))
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break;
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/* Have we run out of nodes to add? */
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if (j == maxcount)
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break;
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assert(!node_list[i]);
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node_list[i] = nodes[j++];
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if (i >= num_found)
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num_found = i + 1;
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}
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}
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return num_found;
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}
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/*
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* This function is a little odd in that it accesses global data. At some
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* point if the architecture board.c files merge this will make more sense.
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* Even now, it is common code.
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*/
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int fdtdec_check_fdt(void)
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{
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/* We must have an fdt */
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if (((uintptr_t)gd->fdt_blob & 3) || fdt_check_header(gd->fdt_blob))
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panic("No valid fdt found - please append one to U-Boot\n"
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"binary or define CONFIG_OF_EMBED\n");
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return 0;
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}
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int fdtdec_lookup_phandle(const void *blob, int node, const char *prop_name)
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{
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const u32 *phandle;
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int lookup;
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phandle = fdt_getprop(blob, node, prop_name, NULL);
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if (!phandle)
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return -FDT_ERR_NOTFOUND;
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lookup = fdt_node_offset_by_phandle(blob, fdt32_to_cpu(*phandle));
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return lookup;
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}
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/**
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* Look up a property in a node and check that it has a minimum length.
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*
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* @param blob FDT blob
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* @param node node to examine
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* @param prop_name name of property to find
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* @param min_len minimum property length in bytes
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* @param err 0 if ok, or -FDT_ERR_NOTFOUND if the property is not
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found, or -FDT_ERR_BADLAYOUT if not enough data
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* @return pointer to cell, which is only valid if err == 0
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*/
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static const void *get_prop_check_min_len(const void *blob, int node,
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const char *prop_name, int min_len, int *err)
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{
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const void *cell;
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int len;
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debug("%s: %s\n", __func__, prop_name);
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cell = fdt_getprop(blob, node, prop_name, &len);
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if (!cell)
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*err = -FDT_ERR_NOTFOUND;
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else if (len < min_len)
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*err = -FDT_ERR_BADLAYOUT;
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else
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*err = 0;
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return cell;
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}
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int fdtdec_get_int_array(const void *blob, int node, const char *prop_name,
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u32 *array, int count)
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{
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const u32 *cell;
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int i, err = 0;
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debug("%s: %s\n", __func__, prop_name);
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cell = get_prop_check_min_len(blob, node, prop_name,
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sizeof(u32) * count, &err);
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if (!err) {
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for (i = 0; i < count; i++)
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array[i] = fdt32_to_cpu(cell[i]);
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}
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return err;
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}
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int fdtdec_get_bool(const void *blob, int node, const char *prop_name)
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{
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const s32 *cell;
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int len;
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debug("%s: %s\n", __func__, prop_name);
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cell = fdt_getprop(blob, node, prop_name, &len);
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return cell != NULL;
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}
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/**
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* Decode a list of GPIOs from an FDT. This creates a list of GPIOs with no
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* terminating item.
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*
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* @param blob FDT blob to use
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* @param node Node to look at
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* @param prop_name Node property name
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* @param gpio Array of gpio elements to fill from FDT. This will be
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* untouched if either 0 or an error is returned
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* @param max_count Maximum number of elements allowed
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* @return number of GPIOs read if ok, -FDT_ERR_BADLAYOUT if max_count would
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* be exceeded, or -FDT_ERR_NOTFOUND if the property is missing.
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*/
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static int fdtdec_decode_gpios(const void *blob, int node,
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const char *prop_name, struct fdt_gpio_state *gpio,
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int max_count)
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{
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const struct fdt_property *prop;
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const u32 *cell;
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const char *name;
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int len, i;
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debug("%s: %s\n", __func__, prop_name);
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assert(max_count > 0);
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prop = fdt_get_property(blob, node, prop_name, &len);
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if (!prop) {
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debug("FDT: %s: property '%s' missing\n", __func__, prop_name);
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return -FDT_ERR_NOTFOUND;
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}
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/* We will use the name to tag the GPIO */
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name = fdt_string(blob, fdt32_to_cpu(prop->nameoff));
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cell = (u32 *)prop->data;
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len /= sizeof(u32) * 3; /* 3 cells per GPIO record */
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if (len > max_count) {
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debug("FDT: %s: too many GPIOs / cells for "
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"property '%s'\n", __func__, prop_name);
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return -FDT_ERR_BADLAYOUT;
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}
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/* Read out the GPIO data from the cells */
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for (i = 0; i < len; i++, cell += 3) {
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gpio[i].gpio = fdt32_to_cpu(cell[1]);
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gpio[i].flags = fdt32_to_cpu(cell[2]);
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gpio[i].name = name;
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}
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return len;
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}
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int fdtdec_decode_gpio(const void *blob, int node, const char *prop_name,
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struct fdt_gpio_state *gpio)
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{
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int err;
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debug("%s: %s\n", __func__, prop_name);
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gpio->gpio = FDT_GPIO_NONE;
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gpio->name = NULL;
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err = fdtdec_decode_gpios(blob, node, prop_name, gpio, 1);
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return err == 1 ? 0 : err;
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}
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int fdtdec_setup_gpio(struct fdt_gpio_state *gpio)
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{
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/*
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* Return success if there is no GPIO defined. This is used for
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* optional GPIOs)
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*/
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if (!fdt_gpio_isvalid(gpio))
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return 0;
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if (gpio_request(gpio->gpio, gpio->name))
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return -1;
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return 0;
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}
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