firewire: add fw_csr_string() helper function
The core (sysfs attributes), the firedtv driver, and possible future drivers all read strings from some configuration ROM directory. Factor out the generic code from show_text_leaf() into a new helper function, modified slightly to handle arbitrary buffer sizes. Signed-off-by: Clemens Ladisch <clemens@ladisch.de> Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
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@ -59,6 +59,67 @@ int fw_csr_iterator_next(struct fw_csr_iterator *ci, int *key, int *value)
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}
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EXPORT_SYMBOL(fw_csr_iterator_next);
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static u32 *search_leaf(u32 *directory, int search_key)
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{
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struct fw_csr_iterator ci;
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int last_key = 0, key, value;
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fw_csr_iterator_init(&ci, directory);
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while (fw_csr_iterator_next(&ci, &key, &value)) {
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if (last_key == search_key &&
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key == (CSR_DESCRIPTOR | CSR_LEAF))
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return ci.p - 1 + value;
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last_key = key;
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}
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return NULL;
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}
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static int textual_leaf_to_string(u32 *block, char *buf, size_t size)
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{
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unsigned int quadlets, length;
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if (!size || !buf)
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return -EINVAL;
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quadlets = min(block[0] >> 16, 256u);
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if (quadlets < 2)
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return -ENODATA;
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if (block[1] != 0 || block[2] != 0)
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/* unknown language/character set */
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return -ENODATA;
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block += 3;
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quadlets -= 2;
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for (length = 0; length < quadlets * 4 && length + 1 < size; length++) {
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char c = block[length / 4] >> (24 - 8 * (length % 4));
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if (c == '\0')
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break;
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buf[length] = c;
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}
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buf[length] = '\0';
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return length;
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}
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/**
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* fw_csr_string - reads a string from the configuration ROM
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* @directory: device or unit directory;
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* fw_device->config_rom+5 or fw_unit->directory
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* @key: the key of the preceding directory entry
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* @buf: where to put the string
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* @size: size of @buf, in bytes
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*
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* Returns string length (>= 0) or error code (< 0).
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*/
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int fw_csr_string(u32 *directory, int key, char *buf, size_t size)
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{
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u32 *leaf = search_leaf(directory, key);
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if (!leaf)
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return -ENOENT;
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return textual_leaf_to_string(leaf, buf, size);
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}
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EXPORT_SYMBOL(fw_csr_string);
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static bool is_fw_unit(struct device *dev);
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static int match_unit_directory(u32 *directory, u32 match_flags,
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@ -226,10 +287,10 @@ static ssize_t show_text_leaf(struct device *dev,
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{
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struct config_rom_attribute *attr =
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container_of(dattr, struct config_rom_attribute, attr);
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struct fw_csr_iterator ci;
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u32 *dir, *block = NULL, *p, *end;
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int length, key, value, last_key = 0, ret = -ENOENT;
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char *b;
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u32 *dir;
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size_t bufsize;
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char dummy_buf[2];
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int ret;
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down_read(&fw_device_rwsem);
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@ -238,40 +299,23 @@ static ssize_t show_text_leaf(struct device *dev,
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else
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dir = fw_device(dev)->config_rom + 5;
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fw_csr_iterator_init(&ci, dir);
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while (fw_csr_iterator_next(&ci, &key, &value)) {
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if (attr->key == last_key &&
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key == (CSR_DESCRIPTOR | CSR_LEAF))
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block = ci.p - 1 + value;
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last_key = key;
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if (buf) {
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bufsize = PAGE_SIZE - 1;
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} else {
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buf = dummy_buf;
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bufsize = 1;
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}
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if (block == NULL)
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goto out;
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length = min(block[0] >> 16, 256U);
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if (length < 3)
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goto out;
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if (block[1] != 0 || block[2] != 0)
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/* Unknown encoding. */
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goto out;
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if (buf == NULL) {
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ret = length * 4;
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goto out;
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}
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b = buf;
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end = &block[length + 1];
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for (p = &block[3]; p < end; p++, b += 4)
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* (u32 *) b = (__force u32) __cpu_to_be32(*p);
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ret = fw_csr_string(dir, attr->key, buf, bufsize);
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if (ret >= 0) {
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/* Strip trailing whitespace and add newline. */
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while (b--, (isspace(*b) || *b == '\0') && b > buf);
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strcpy(b + 1, "\n");
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ret = b + 2 - buf;
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out:
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while (ret > 0 && isspace(buf[ret - 1]))
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ret--;
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strcpy(buf + ret, "\n");
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ret++;
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}
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up_read(&fw_device_rwsem);
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return ret;
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@ -239,47 +239,18 @@ static const struct fw_address_region fcp_region = {
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};
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/* Adjust the template string if models with longer names appear. */
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#define MAX_MODEL_NAME_LEN ((int)DIV_ROUND_UP(sizeof("FireDTV ????"), 4))
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static size_t model_name(u32 *directory, __be32 *buffer)
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{
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struct fw_csr_iterator ci;
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int i, length, key, value, last_key = 0;
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u32 *block = NULL;
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fw_csr_iterator_init(&ci, directory);
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while (fw_csr_iterator_next(&ci, &key, &value)) {
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if (last_key == CSR_MODEL &&
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key == (CSR_DESCRIPTOR | CSR_LEAF))
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block = ci.p - 1 + value;
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last_key = key;
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}
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if (block == NULL)
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return 0;
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length = min((int)(block[0] >> 16) - 2, MAX_MODEL_NAME_LEN);
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if (length <= 0)
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return 0;
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/* fast-forward to text string */
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block += 3;
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for (i = 0; i < length; i++)
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buffer[i] = cpu_to_be32(block[i]);
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return length * 4;
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}
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#define MAX_MODEL_NAME_LEN sizeof("FireDTV ????")
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static int node_probe(struct device *dev)
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{
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struct firedtv *fdtv;
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__be32 name[MAX_MODEL_NAME_LEN];
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char name[MAX_MODEL_NAME_LEN];
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int name_len, err;
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name_len = model_name(fw_unit(dev)->directory, name);
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name_len = fw_csr_string(fw_unit(dev)->directory, CSR_MODEL,
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name, sizeof(name));
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fdtv = fdtv_alloc(dev, &backend, (char *)name, name_len);
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fdtv = fdtv_alloc(dev, &backend, name, name_len >= 0 ? name_len : 0);
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if (!fdtv)
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return -ENOMEM;
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@ -72,6 +72,8 @@ struct fw_csr_iterator {
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void fw_csr_iterator_init(struct fw_csr_iterator *ci, u32 *p);
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int fw_csr_iterator_next(struct fw_csr_iterator *ci, int *key, int *value);
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int fw_csr_string(u32 *directory, int key, char *buf, size_t size);
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extern struct bus_type fw_bus_type;
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struct fw_card_driver;
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