Date: Thu, 24 Dec 2009 11:59:57 +0100 From: Clemens Ladisch Subject: 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 Signed-off-by: Stefan Richter --- drivers/firewire/core-device.c | 110 +++++++++++++++++------- drivers/media/dvb/firewire/firedtv-fw.c | 39 +-------- include/linux/firewire.h | 2 + 3 files changed, 84 insertions(+), 67 deletions(-) Index: linux-2.6.33-rc2/include/linux/firewire.h =================================================================== --- linux-2.6.33-rc2.orig/include/linux/firewire.h +++ linux-2.6.33-rc2/include/linux/firewire.h @@ -72,6 +72,8 @@ struct fw_csr_iterator { void fw_csr_iterator_init(struct fw_csr_iterator *ci, u32 *p); int fw_csr_iterator_next(struct fw_csr_iterator *ci, int *key, int *value); +int fw_csr_string(u32 *directory, int key, char *buf, size_t size); + extern struct bus_type fw_bus_type; struct fw_card_driver; Index: linux-2.6.33-rc2/drivers/firewire/core-device.c =================================================================== --- linux-2.6.33-rc2.orig/drivers/firewire/core-device.c +++ linux-2.6.33-rc2/drivers/firewire/core-device.c @@ -59,6 +59,67 @@ int fw_csr_iterator_next(struct fw_csr_i } EXPORT_SYMBOL(fw_csr_iterator_next); +static u32 *search_leaf(u32 *directory, int search_key) +{ + struct fw_csr_iterator ci; + int last_key = 0, key, value; + + fw_csr_iterator_init(&ci, directory); + while (fw_csr_iterator_next(&ci, &key, &value)) { + if (last_key == search_key && + key == (CSR_DESCRIPTOR | CSR_LEAF)) + return ci.p - 1 + value; + last_key = key; + } + return NULL; +} + +static int textual_leaf_to_string(u32 *block, char *buf, size_t size) +{ + unsigned int quadlets, length; + + if (!size || !buf) + return -EINVAL; + + quadlets = min(block[0] >> 16, 256u); + if (quadlets < 2) + return -ENODATA; + + if (block[1] != 0 || block[2] != 0) + /* unknown language/character set */ + return -ENODATA; + + block += 3; + quadlets -= 2; + for (length = 0; length < quadlets * 4 && length + 1 < size; length++) { + char c = block[length / 4] >> (24 - 8 * (length % 4)); + if (c == '\0') + break; + buf[length] = c; + } + buf[length] = '\0'; + return length; +} + +/** + * fw_csr_string - reads a string from the configuration ROM + * @directory: device or unit directory; + * fw_device->config_rom+5 or fw_unit->directory + * @key: the key of the preceding directory entry + * @buf: where to put the string + * @size: size of @buf, in bytes + * + * Returns string length (>= 0) or error code (< 0). + */ +int fw_csr_string(u32 *directory, int key, char *buf, size_t size) +{ + u32 *leaf = search_leaf(directory, key); + if (!leaf) + return -ENOENT; + return textual_leaf_to_string(leaf, buf, size); +} +EXPORT_SYMBOL(fw_csr_string); + static bool is_fw_unit(struct device *dev); static int match_unit_directory(u32 *directory, u32 match_flags, @@ -226,10 +287,10 @@ static ssize_t show_text_leaf(struct dev { struct config_rom_attribute *attr = container_of(dattr, struct config_rom_attribute, attr); - struct fw_csr_iterator ci; - u32 *dir, *block = NULL, *p, *end; - int length, key, value, last_key = 0, ret = -ENOENT; - char *b; + u32 *dir; + size_t bufsize; + char dummy_buf[2]; + int ret; down_read(&fw_device_rwsem); @@ -238,40 +299,23 @@ static ssize_t show_text_leaf(struct dev else dir = fw_device(dev)->config_rom + 5; - fw_csr_iterator_init(&ci, dir); - while (fw_csr_iterator_next(&ci, &key, &value)) { - if (attr->key == last_key && - key == (CSR_DESCRIPTOR | CSR_LEAF)) - block = ci.p - 1 + value; - last_key = key; + if (buf) { + bufsize = PAGE_SIZE - 1; + } else { + buf = dummy_buf; + bufsize = 1; } - if (block == NULL) - goto out; - - length = min(block[0] >> 16, 256U); - if (length < 3) - goto out; - - if (block[1] != 0 || block[2] != 0) - /* Unknown encoding. */ - goto out; + ret = fw_csr_string(dir, attr->key, buf, bufsize); - if (buf == NULL) { - ret = length * 4; - goto out; + if (ret >= 0) { + /* Strip trailing whitespace and add newline. */ + while (ret > 0 && isspace(buf[ret - 1])) + ret--; + strcpy(buf + ret, "\n"); + ret++; } - b = buf; - end = &block[length + 1]; - for (p = &block[3]; p < end; p++, b += 4) - * (u32 *) b = (__force u32) __cpu_to_be32(*p); - - /* Strip trailing whitespace and add newline. */ - while (b--, (isspace(*b) || *b == '\0') && b > buf); - strcpy(b + 1, "\n"); - ret = b + 2 - buf; - out: up_read(&fw_device_rwsem); return ret; Index: linux-2.6.33-rc2/drivers/media/dvb/firewire/firedtv-fw.c =================================================================== --- linux-2.6.33-rc2.orig/drivers/media/dvb/firewire/firedtv-fw.c +++ linux-2.6.33-rc2/drivers/media/dvb/firewire/firedtv-fw.c @@ -239,47 +239,18 @@ static const struct fw_address_region fc }; /* Adjust the template string if models with longer names appear. */ -#define MAX_MODEL_NAME_LEN ((int)DIV_ROUND_UP(sizeof("FireDTV ????"), 4)) - -static size_t model_name(u32 *directory, __be32 *buffer) -{ - struct fw_csr_iterator ci; - int i, length, key, value, last_key = 0; - u32 *block = NULL; - - fw_csr_iterator_init(&ci, directory); - while (fw_csr_iterator_next(&ci, &key, &value)) { - if (last_key == CSR_MODEL && - key == (CSR_DESCRIPTOR | CSR_LEAF)) - block = ci.p - 1 + value; - last_key = key; - } - - if (block == NULL) - return 0; - - length = min((int)(block[0] >> 16) - 2, MAX_MODEL_NAME_LEN); - if (length <= 0) - return 0; - - /* fast-forward to text string */ - block += 3; - - for (i = 0; i < length; i++) - buffer[i] = cpu_to_be32(block[i]); - - return length * 4; -} +#define MAX_MODEL_NAME_LEN sizeof("FireDTV ????") static int node_probe(struct device *dev) { struct firedtv *fdtv; - __be32 name[MAX_MODEL_NAME_LEN]; + char name[MAX_MODEL_NAME_LEN]; int name_len, err; - name_len = model_name(fw_unit(dev)->directory, name); + name_len = fw_csr_string(fw_unit(dev)->directory, CSR_MODEL, + name, sizeof(name)); - fdtv = fdtv_alloc(dev, &backend, (char *)name, name_len); + fdtv = fdtv_alloc(dev, &backend, name, name_len >= 0 ? name_len : 0); if (!fdtv) return -ENOMEM;