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Commit 1f8fef7b authored by Clemens Ladisch's avatar Clemens Ladisch Committed by Stefan Richter
Browse files

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: default avatarClemens Ladisch <clemens@ladisch.de>
Signed-off-by: default avatarStefan Richter <stefanr@s5r6.in-berlin.de>
parent 5d7db049

drivers/firewire/core-device.c

+77 −33
Original line number Diff line number Diff line
@@ -59,6 +59,67 @@ int fw_csr_iterator_next(struct fw_csr_iterator *ci, int *key, int *value) 
}

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 device *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 device *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;

drivers/media/dvb/firewire/firedtv-fw.c

+5 −34
Original line number Diff line number Diff line
@@ -239,47 +239,18 @@ static const struct fw_address_region fcp_region = { 
};



/* 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;

include/linux/firewire.h

+2 −0
Original line number Diff line number Diff line
@@ -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;