csr1212.c

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/*
 * csr1212.c -- IEEE 1212 Control and Status Register support for Linux
 *
 * Copyright (C) 2003 Francois Retief <[e-mail]>
 *                    Steve Kinneberg <[e-mail]>
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
 *    1. Redistributions of source code must retain the above copyright notice,
 *       this list of conditions and the following disclaimer.
 *    2. Redistributions in binary form must reproduce the above copyright
 *       notice, this list of conditions and the following disclaimer in the
 *       documentation and/or other materials provided with the distribution.
 *    3. The name of the author may not be used to endorse or promote products
 *       derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO
 * EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
 * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
 * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
 * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
 * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */


/* TODO List:
 * - Verify interface consistency: i.e., public functions that take a size
 *   parameter expect size to be in bytes.
 */

#include <linux/errno.h>
#include <linux/kernel.h>
#include <linux/string.h>
#include <asm/bug.h>
#include <asm/byteorder.h>

#include "csr1212.h"


/* Permitted key type for each key id */
#define __I (1 << CSR1212_KV_TYPE_IMMEDIATE)
#define __C (1 << CSR1212_KV_TYPE_CSR_OFFSET)
#define __D (1 << CSR1212_KV_TYPE_DIRECTORY)
#define __L (1 << CSR1212_KV_TYPE_LEAF)
static const u8 csr1212_key_id_type_map[0x30] = {
	__C,			/* used by Apple iSight */
	__D | __L,		/* Descriptor */
	__I | __D | __L,	/* Bus_Dependent_Info */
	__I | __D | __L,	/* Vendor */
	__I,			/* Hardware_Version */
	0, 0,			/* Reserved */
	__D | __L | __I,	/* Module */
	__I, 0, 0, 0,		/* used by Apple iSight, Reserved */
	__I,			/* Node_Capabilities */
	__L,			/* EUI_64 */
	0, 0, 0,		/* Reserved */
	__D,			/* Unit */
	__I,			/* Specifier_ID */
	__I,			/* Version */
	__I | __C | __D | __L,	/* Dependent_Info */
	__L,			/* Unit_Location */
	0,			/* Reserved */
	__I,			/* Model */
	__D,			/* Instance */
	__L,			/* Keyword */
	__D,			/* Feature */
	__L,			/* Extended_ROM */
	__I,			/* Extended_Key_Specifier_ID */
	__I,			/* Extended_Key */
	__I | __C | __D | __L,	/* Extended_Data */
	__L,			/* Modifiable_Descriptor */
	__I,			/* Directory_ID */
	__I,			/* Revision */
};
#undef __I
#undef __C
#undef __D
#undef __L


#define quads_to_bytes(_q) ((_q) * sizeof(u32))
#define bytes_to_quads(_b) (((_b) + sizeof(u32) - 1) / sizeof(u32))

static void free_keyval(struct csr1212_keyval *kv)
{
	if ((kv->key.type == CSR1212_KV_TYPE_LEAF) &&
	    (kv->key.id != CSR1212_KV_ID_EXTENDED_ROM))
		CSR1212_FREE(kv->value.leaf.data);

	CSR1212_FREE(kv);
}

static u16 csr1212_crc16(const u32 *buffer, size_t length)
{
	int shift;
	u32 data;
	u16 sum, crc = 0;

	for (; length; length--) {
		data = be32_to_cpu(*buffer);
		buffer++;
		for (shift = 28; shift >= 0; shift -= 4 ) {
			sum = ((crc >> 12) ^ (data >> shift)) & 0xf;
			crc = (crc << 4) ^ (sum << 12) ^ (sum << 5) ^ (sum);
		}
		crc &= 0xffff;
	}

	return cpu_to_be16(crc);
}

/* Microsoft computes the CRC with the bytes in reverse order. */
static u16 csr1212_msft_crc16(const u32 *buffer, size_t length)
{
	int shift;
	u32 data;
	u16 sum, crc = 0;

	for (; length; length--) {
		data = le32_to_cpu(*buffer);
		buffer++;
		for (shift = 28; shift >= 0; shift -= 4 ) {
			sum = ((crc >> 12) ^ (data >> shift)) & 0xf;
			crc = (crc << 4) ^ (sum << 12) ^ (sum << 5) ^ (sum);
		}
		crc &= 0xffff;
	}

	return cpu_to_be16(crc);
}

static struct csr1212_dentry *
csr1212_find_keyval(struct csr1212_keyval *dir, struct csr1212_keyval *kv)
{
	struct csr1212_dentry *pos;

	for (pos = dir->value.directory.dentries_head;
	     pos != NULL; pos = pos->next)
		if (pos->kv == kv)
			return pos;
	return NULL;
}

static struct csr1212_keyval *
csr1212_find_keyval_offset(struct csr1212_keyval *kv_list, u32 offset)
{
	struct csr1212_keyval *kv;

	for (kv = kv_list->next; kv && (kv != kv_list); kv = kv->next)
		if (kv->offset == offset)
			return kv;
	return NULL;
}


/* Creation Routines */

struct csr1212_csr *csr1212_create_csr(struct csr1212_bus_ops *ops,
				       size_t bus_info_size, void *private)
{
	struct csr1212_csr *csr;

	csr = CSR1212_MALLOC(sizeof(*csr));
	if (!csr)
		return NULL;

	csr->cache_head =
		csr1212_rom_cache_malloc(CSR1212_CONFIG_ROM_SPACE_OFFSET,
					 CSR1212_CONFIG_ROM_SPACE_SIZE);
	if (!csr->cache_head) {
		CSR1212_FREE(csr);
		return NULL;
	}

	/* The keyval key id is not used for the root node, but a valid key id
	 * that can be used for a directory needs to be passed to
	 * csr1212_new_directory(). */
	csr->root_kv = csr1212_new_directory(CSR1212_KV_ID_VENDOR);
	if (!csr->root_kv) {
		CSR1212_FREE(csr->cache_head);
		CSR1212_FREE(csr);
		return NULL;
	}

	csr->bus_info_data = csr->cache_head->data;
	csr->bus_info_len = bus_info_size;
	csr->crc_len = bus_info_size;
	csr->ops = ops;
	csr->private = private;
	csr->cache_tail = csr->cache_head;

	return csr;
}

void csr1212_init_local_csr(struct csr1212_csr *csr,
			    const u32 *bus_info_data, int max_rom)
{
	static const int mr_map[] = { 4, 64, 1024, 0 };

	BUG_ON(max_rom & ~0x3);
	csr->max_rom = mr_map[max_rom];
	memcpy(csr->bus_info_data, bus_info_data, csr->bus_info_len);
}

static struct csr1212_keyval *csr1212_new_keyval(u8 type, u8 key)
{
	struct csr1212_keyval *kv;

	if (key < 0x30 && ((csr1212_key_id_type_map[key] & (1 << type)) == 0))
		return NULL;

	kv = CSR1212_MALLOC(sizeof(*kv));
	if (!kv)
		return NULL;

	atomic_set(&kv->refcnt, 1);
	kv->key.type = type;
	kv->key.id = key;
	kv->associate = NULL;
	kv->next = NULL;
	kv->prev = NULL;
	kv->offset = 0;
	kv->valid = 0;
	return kv;
}

struct csr1212_keyval *csr1212_new_immediate(u8 key, u32 value)
{
	struct csr1212_keyval *kv;

	kv = csr1212_new_keyval(CSR1212_KV_TYPE_IMMEDIATE, key);
	if (!kv)
		return NULL;

	kv->value.immediate = value;
	kv->valid = 1;
	return kv;
}

static struct csr1212_keyval *
csr1212_new_leaf(u8 key, const void *data, size_t data_len)
{
	struct csr1212_keyval *kv;

	kv = csr1212_new_keyval(CSR1212_KV_TYPE_LEAF, key);
	if (!kv)
		return NULL;

	if (data_len > 0) {
		kv->value.leaf.data = CSR1212_MALLOC(data_len);
		if (!kv->value.leaf.data) {
			CSR1212_FREE(kv);
			return NULL;
		}

		if (data)
			memcpy(kv->value.leaf.data, data, data_len);
	} else {
		kv->value.leaf.data = NULL;
	}

	kv->value.leaf.len = bytes_to_quads(data_len);
	kv->offset = 0;
	kv->valid = 1;

	return kv;
}

static struct csr1212_keyval *
csr1212_new_csr_offset(u8 key, u32 csr_offset)
{
	struct csr1212_keyval *kv;

	kv = csr1212_new_keyval(CSR1212_KV_TYPE_CSR_OFFSET, key);
	if (!kv)
		return NULL;

	kv->value.csr_offset = csr_offset;

	kv->offset = 0;
	kv->valid = 1;
	return kv;
}

struct csr1212_keyval *csr1212_new_directory(u8 key)
{
	struct csr1212_keyval *kv;

	kv = csr1212_new_keyval(CSR1212_KV_TYPE_DIRECTORY, key);
	if (!kv)
		return NULL;

	kv->value.directory.len = 0;
	kv->offset = 0;
	kv->value.directory.dentries_head = NULL;
	kv->value.directory.dentries_tail = NULL;
	kv->valid = 1;
	return kv;
}

void csr1212_associate_keyval(struct csr1212_keyval *kv,
			      struct csr1212_keyval *associate)
{
	BUG_ON(!kv || !associate || kv->key.id == CSR1212_KV_ID_DESCRIPTOR ||
	       (associate->key.id != CSR1212_KV_ID_DESCRIPTOR &&
		associate->key.id != CSR1212_KV_ID_DEPENDENT_INFO &&
		associate->key.id != CSR1212_KV_ID_EXTENDED_KEY &&
		associate->key.id != CSR1212_KV_ID_EXTENDED_DATA &&
		associate->key.id < 0x30) ||
	       (kv->key.id == CSR1212_KV_ID_EXTENDED_KEY_SPECIFIER_ID &&
		associate->key.id != CSR1212_KV_ID_EXTENDED_KEY) ||
	       (kv->key.id == CSR1212_KV_ID_EXTENDED_KEY &&
		associate->key.id != CSR1212_KV_ID_EXTENDED_DATA) ||
	       (associate->key.id == CSR1212_KV_ID_EXTENDED_KEY &&
		kv->key.id != CSR1212_KV_ID_EXTENDED_KEY_SPECIFIER_ID) ||
	       (associate->key.id == CSR1212_KV_ID_EXTENDED_DATA &&
		kv->key.id != CSR1212_KV_ID_EXTENDED_KEY));

	if (kv->associate)
		csr1212_release_keyval(kv->associate);

	csr1212_keep_keyval(associate);
	kv->associate = associate;
}

static int __csr1212_attach_keyval_to_directory(struct csr1212_keyval *dir,
						struct csr1212_keyval *kv,
						bool keep_keyval)
{
	struct csr1212_dentry *dentry;

	BUG_ON(!kv || !dir || dir->key.type != CSR1212_KV_TYPE_DIRECTORY);

	dentry = CSR1212_MALLOC(sizeof(*dentry));
	if (!dentry)
		return -ENOMEM;

	if (keep_keyval)
		csr1212_keep_keyval(kv);
	dentry->kv = kv;

	dentry->next = NULL;
	dentry->prev = dir->value.directory.dentries_tail;

	if (!dir->value.directory.dentries_head)
		dir->value.directory.dentries_head = dentry;

	if (dir->value.directory.dentries_tail)
		dir->value.directory.dentries_tail->next = dentry;
	dir->value.directory.dentries_tail = dentry;

	return CSR1212_SUCCESS;
}

int csr1212_attach_keyval_to_directory(struct csr1212_keyval *dir,
				       struct csr1212_keyval *kv)
{
	return __csr1212_attach_keyval_to_directory(dir, kv, true);
}

#define CSR1212_DESCRIPTOR_LEAF_DATA(kv) \
	(&((kv)->value.leaf.data[1]))

#define CSR1212_DESCRIPTOR_LEAF_SET_TYPE(kv, type) \
	((kv)->value.leaf.data[0] = \
	 cpu_to_be32(CSR1212_DESCRIPTOR_LEAF_SPECIFIER_ID(kv) | \
		     ((type) << CSR1212_DESCRIPTOR_LEAF_TYPE_SHIFT)))
#define CSR1212_DESCRIPTOR_LEAF_SET_SPECIFIER_ID(kv, spec_id) \
	((kv)->value.leaf.data[0] = \
	 cpu_to_be32((CSR1212_DESCRIPTOR_LEAF_TYPE(kv) << \
		      CSR1212_DESCRIPTOR_LEAF_TYPE_SHIFT) | \
		     ((spec_id) & CSR1212_DESCRIPTOR_LEAF_SPECIFIER_ID_MASK)))

static struct csr1212_keyval *
csr1212_new_descriptor_leaf(u8 dtype, u32 specifier_id,
			    const void *data, size_t data_len)
{
	struct csr1212_keyval *kv;

	kv = csr1212_new_leaf(CSR1212_KV_ID_DESCRIPTOR, NULL,
			      data_len + CSR1212_DESCRIPTOR_LEAF_OVERHEAD);
	if (!kv)
		return NULL;

	CSR1212_DESCRIPTOR_LEAF_SET_TYPE(kv, dtype);
	CSR1212_DESCRIPTOR_LEAF_SET_SPECIFIER_ID(kv, specifier_id);

	if (data)
		memcpy(CSR1212_DESCRIPTOR_LEAF_DATA(kv), data, data_len);

	return kv;
}

/* Check if string conforms to minimal ASCII as per IEEE 1212 clause 7.4 */
static int csr1212_check_minimal_ascii(const char *s)
{
	static const char minimal_ascii_table[] = {
					/*  1   2   4   8  16  32  64  128 */
		128,			/* --, --, --, --, --, --, --, 07, */
		4 + 16 + 32,		/* --, --, 0a, --, 0C, 0D, --, --, */
		0,			/* --, --, --, --, --, --, --, --, */
		0,			/* --, --, --, --, --, --, --, --, */
		255 - 8 - 16,		/* 20, 21, 22, --, --, 25, 26, 27, */
		255,			/* 28, 29, 2a, 2b, 2c, 2d, 2e, 2f, */
		255,			/* 30, 31, 32, 33, 34, 35, 36, 37, */
		255,			/* 38, 39, 3a, 3b, 3c, 3d, 3e, 3f, */
		255,			/* 40, 41, 42, 43, 44, 45, 46, 47, */
		255,			/* 48, 49, 4a, 4b, 4c, 4d, 4e, 4f, */
		255,			/* 50, 51, 52, 53, 54, 55, 56, 57, */
		1 + 2 + 4 + 128,	/* 58, 59, 5a, --, --, --, --, 5f, */
		255 - 1,		/* --, 61, 62, 63, 64, 65, 66, 67, */
		255,			/* 68, 69, 6a, 6b, 6c, 6d, 6e, 6f, */
		255,			/* 70, 71, 72, 73, 74, 75, 76, 77, */
		1 + 2 + 4,		/* 78, 79, 7a, --, --, --, --, --, */
	};
	int i, j;

	for (; *s; s++) {
		i = *s >> 3;		/*  i = *s / 8;		*/
		j = 1 << (*s & 3);	/*  j = 1 << (*s % 8);	*/

		if (i >= ARRAY_SIZE(minimal_ascii_table) ||
		    !(minimal_ascii_table[i] & j))
			return -EINVAL;
	}
	return 0;
}

/* IEEE 1212 clause 7.5.4.1 textual descriptors (English, minimal ASCII) */
struct csr1212_keyval *csr1212_new_string_descriptor_leaf(const char *s)
{
	struct csr1212_keyval *kv;
	u32 *text;
	size_t str_len, quads;

	if (!s || !*s || csr1212_check_minimal_ascii(s))
		return NULL;

	str_len = strlen(s);
	quads = bytes_to_quads(str_len);
	kv = csr1212_new_descriptor_leaf(0, 0, NULL, quads_to_bytes(quads) +
				      CSR1212_TEXTUAL_DESCRIPTOR_LEAF_OVERHEAD);
	if (!kv)
		return NULL;

	kv->value.leaf.data[1] = 0;	/* width, character_set, language */
	text = CSR1212_TEXTUAL_DESCRIPTOR_LEAF_DATA(kv);
	text[quads - 1] = 0;		/* padding */
	memcpy(text, s, str_len);

	return kv;
}


/* Destruction Routines */

void csr1212_detach_keyval_from_directory(struct csr1212_keyval *dir,
					  struct csr1212_keyval *kv)
{
	struct csr1212_dentry *dentry;

	if (!kv || !dir || dir->key.type != CSR1212_KV_TYPE_DIRECTORY)
		return;

	dentry = csr1212_find_keyval(dir, kv);

	if (!dentry)
		return;

	if (dentry->prev)
		dentry->prev->next = dentry->next;
	if (dentry->next)
		dentry->next->prev = dentry->prev;
	if (dir->value.directory.dentries_head == dentry)
		dir->value.directory.dentries_head = dentry->next;
	if (dir->value.directory.dentries_tail == dentry)
		dir->value.directory.dentries_tail = dentry->prev;

	CSR1212_FREE(dentry);

	csr1212_release_keyval(kv);
}

/* This function is used to free the memory taken by a keyval.  If the given
 * keyval is a directory type, then any keyvals contained in that directory
 * will be destroyed as well if noone holds a reference on them.  By means of