Revision 00d8689b85a7bb37cc57ba4c40bd46325f51ced4 authored by Thomas Petazzoni on 11 December 2014, 16:33:46 UTC, committed by Wolfram Sang on 17 December 2014, 18:26:03 UTC
Originally, the I2C controller supported by the i2c-mv64xxx driver requires a lot of software support: an interrupt is generated at each step of an I2C transaction (after the start bit, after sending the address, etc.) and the driver is in charge of re-programming the I2C controller to do the next step of the I2C transaction. This explains the fairly complex state machine that the driver has. On Marvell Armada XP and later processors (Armada 375, 38x, etc.), the I2C controller was extended with a part called the "I2C Bridge", which allows to offload the I2C transaction completely to the hardware. Initial support for this mechanism was added in commit 930ab3d403a ("i2c: mv64xxx: Add I2C Transaction Generator support"). However, the implementation done in this commit has two related issues, which this commit fixes by completely changing how the offload implementation is done: * SMBus read transfers, where there is one write to select the register immediately followed in the same transaction by one read, were making the processor hang. This was easier visible on the Marvell Armada XP WRT1900AC platform using a driver for an I2C LED controller, or on other Armada XP platforms by using a simple 'i2cget' command to read an I2C EEPROM. * The implementation was based on the fact that the offload engine was re-programmed to transfer each message of an I2C xfer: this meant that each message sent with the offload engine was starting with a normal I2C start sequence. However, the I2C subsystem assumes that all messages belonging to the same xfer will use the so-called "repeated start" so that the entire I2C xfer is seen as one transfer by the I2C devices and cannot be interrupt by other I2C masters on the same bus. In fact, the "I2C Bridge" allows to offload three types of xfer: - xfer of one write message - xfer of one read message - xfer of one write message followed by one read message For all other situations, we have to fallback to not using the "I2C Bridge" in order to get proper I2C semantics. Therefore, this commit reworks the offload implementation to put it not at the message level, but at the xfer level: in the mv64xxx_i2c_xfer() function, we decide if the transaction can be offloaded (in which case it is handled by the mv64xxx_i2c_offload_xfer() function), or otherwise it is handled by the slow path (implemented in the existing mv64xxx_i2c_execute_msg()). This allows to simplify the state machine, which no longer needs to have any state related to the offload implementation: the offload implementation is now completely separated from the slow path (with the exception of the interrupt handler, of course). In summary: - mv64xxx_i2c_can_offload() will analyze an I2C xfer and decided of the "I2C Bridge" can be used to offload it or not. - mv64xxx_i2c_offload_xfer() will actually program the "I2C Bridge" to offload one xfer (of either one or two messages), and block using mv64xxx_i2c_wait_for_completion() until the xfer completes. - The interrupt handler mv64xxx_i2c_intr() is modified to push the offload related code to a separate function, mv64xxx_i2c_intr_offload(). It will take care of reading the received data if needed. This commit was tested on: - Armada XP OpenBlocks AX3-4 (EEPROM on I2C and RTC on I2C) - Armada XP WRT1900AC (LED controller on I2C) - Armada XP GP (EEPROM on I2C) Fixes: 930ab3d403ae ("i2c: mv64xxx: Add I2C Transaction Generator support") Cc: <stable@vger.kernel.org> # v3.12+ Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com> [wsa: fixed checkpatch warnings] Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
1 parent 1259869
api.c
/*
* Scatterlist Cryptographic API.
*
* Copyright (c) 2002 James Morris <jmorris@intercode.com.au>
* Copyright (c) 2002 David S. Miller (davem@redhat.com)
* Copyright (c) 2005 Herbert Xu <herbert@gondor.apana.org.au>
*
* Portions derived from Cryptoapi, by Alexander Kjeldaas <astor@fast.no>
* and Nettle, by Niels Möller.
*
* This program is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License as published by the Free
* Software Foundation; either version 2 of the License, or (at your option)
* any later version.
*
*/
#include <linux/err.h>
#include <linux/errno.h>
#include <linux/kernel.h>
#include <linux/kmod.h>
#include <linux/module.h>
#include <linux/param.h>
#include <linux/sched.h>
#include <linux/slab.h>
#include <linux/string.h>
#include "internal.h"
LIST_HEAD(crypto_alg_list);
EXPORT_SYMBOL_GPL(crypto_alg_list);
DECLARE_RWSEM(crypto_alg_sem);
EXPORT_SYMBOL_GPL(crypto_alg_sem);
BLOCKING_NOTIFIER_HEAD(crypto_chain);
EXPORT_SYMBOL_GPL(crypto_chain);
static struct crypto_alg *crypto_larval_wait(struct crypto_alg *alg);
struct crypto_alg *crypto_mod_get(struct crypto_alg *alg)
{
return try_module_get(alg->cra_module) ? crypto_alg_get(alg) : NULL;
}
EXPORT_SYMBOL_GPL(crypto_mod_get);
void crypto_mod_put(struct crypto_alg *alg)
{
struct module *module = alg->cra_module;
crypto_alg_put(alg);
module_put(module);
}
EXPORT_SYMBOL_GPL(crypto_mod_put);
static inline int crypto_is_test_larval(struct crypto_larval *larval)
{
return larval->alg.cra_driver_name[0];
}
static struct crypto_alg *__crypto_alg_lookup(const char *name, u32 type,
u32 mask)
{
struct crypto_alg *q, *alg = NULL;
int best = -2;
list_for_each_entry(q, &crypto_alg_list, cra_list) {
int exact, fuzzy;
if (crypto_is_moribund(q))
continue;
if ((q->cra_flags ^ type) & mask)
continue;
if (crypto_is_larval(q) &&
!crypto_is_test_larval((struct crypto_larval *)q) &&
((struct crypto_larval *)q)->mask != mask)
continue;
exact = !strcmp(q->cra_driver_name, name);
fuzzy = !strcmp(q->cra_name, name);
if (!exact && !(fuzzy && q->cra_priority > best))
continue;
if (unlikely(!crypto_mod_get(q)))
continue;
best = q->cra_priority;
if (alg)
crypto_mod_put(alg);
alg = q;
if (exact)
break;
}
return alg;
}
static void crypto_larval_destroy(struct crypto_alg *alg)
{
struct crypto_larval *larval = (void *)alg;
BUG_ON(!crypto_is_larval(alg));
if (larval->adult)
crypto_mod_put(larval->adult);
kfree(larval);
}
struct crypto_larval *crypto_larval_alloc(const char *name, u32 type, u32 mask)
{
struct crypto_larval *larval;
larval = kzalloc(sizeof(*larval), GFP_KERNEL);
if (!larval)
return ERR_PTR(-ENOMEM);
larval->mask = mask;
larval->alg.cra_flags = CRYPTO_ALG_LARVAL | type;
larval->alg.cra_priority = -1;
larval->alg.cra_destroy = crypto_larval_destroy;
strlcpy(larval->alg.cra_name, name, CRYPTO_MAX_ALG_NAME);
init_completion(&larval->completion);
return larval;
}
EXPORT_SYMBOL_GPL(crypto_larval_alloc);
static struct crypto_alg *crypto_larval_add(const char *name, u32 type,
u32 mask)
{
struct crypto_alg *alg;
struct crypto_larval *larval;
larval = crypto_larval_alloc(name, type, mask);
if (IS_ERR(larval))
return ERR_CAST(larval);
atomic_set(&larval->alg.cra_refcnt, 2);
down_write(&crypto_alg_sem);
alg = __crypto_alg_lookup(name, type, mask);
if (!alg) {
alg = &larval->alg;
list_add(&alg->cra_list, &crypto_alg_list);
}
up_write(&crypto_alg_sem);
if (alg != &larval->alg) {
kfree(larval);
if (crypto_is_larval(alg))
alg = crypto_larval_wait(alg);
}
return alg;
}
void crypto_larval_kill(struct crypto_alg *alg)
{
struct crypto_larval *larval = (void *)alg;
down_write(&crypto_alg_sem);
list_del(&alg->cra_list);
up_write(&crypto_alg_sem);
complete_all(&larval->completion);
crypto_alg_put(alg);
}
EXPORT_SYMBOL_GPL(crypto_larval_kill);
static struct crypto_alg *crypto_larval_wait(struct crypto_alg *alg)
{
struct crypto_larval *larval = (void *)alg;
long timeout;
timeout = wait_for_completion_interruptible_timeout(
&larval->completion, 60 * HZ);
alg = larval->adult;
if (timeout < 0)
alg = ERR_PTR(-EINTR);
else if (!timeout)
alg = ERR_PTR(-ETIMEDOUT);
else if (!alg)
alg = ERR_PTR(-ENOENT);
else if (crypto_is_test_larval(larval) &&
!(alg->cra_flags & CRYPTO_ALG_TESTED))
alg = ERR_PTR(-EAGAIN);
else if (!crypto_mod_get(alg))
alg = ERR_PTR(-EAGAIN);
crypto_mod_put(&larval->alg);
return alg;
}
struct crypto_alg *crypto_alg_lookup(const char *name, u32 type, u32 mask)
{
struct crypto_alg *alg;
down_read(&crypto_alg_sem);
alg = __crypto_alg_lookup(name, type, mask);
up_read(&crypto_alg_sem);
return alg;
}
EXPORT_SYMBOL_GPL(crypto_alg_lookup);
struct crypto_alg *crypto_larval_lookup(const char *name, u32 type, u32 mask)
{
struct crypto_alg *alg;
if (!name)
return ERR_PTR(-ENOENT);
mask &= ~(CRYPTO_ALG_LARVAL | CRYPTO_ALG_DEAD);
type &= mask;
alg = crypto_alg_lookup(name, type, mask);
if (!alg) {
request_module("crypto-%s", name);
if (!((type ^ CRYPTO_ALG_NEED_FALLBACK) & mask &
CRYPTO_ALG_NEED_FALLBACK))
request_module("crypto-%s-all", name);
alg = crypto_alg_lookup(name, type, mask);
}
if (alg)
return crypto_is_larval(alg) ? crypto_larval_wait(alg) : alg;
return crypto_larval_add(name, type, mask);
}
EXPORT_SYMBOL_GPL(crypto_larval_lookup);
int crypto_probing_notify(unsigned long val, void *v)
{
int ok;
ok = blocking_notifier_call_chain(&crypto_chain, val, v);
if (ok == NOTIFY_DONE) {
request_module("cryptomgr");
ok = blocking_notifier_call_chain(&crypto_chain, val, v);
}
return ok;
}
EXPORT_SYMBOL_GPL(crypto_probing_notify);
struct crypto_alg *crypto_alg_mod_lookup(const char *name, u32 type, u32 mask)
{
struct crypto_alg *alg;
struct crypto_alg *larval;
int ok;
if (!((type | mask) & CRYPTO_ALG_TESTED)) {
type |= CRYPTO_ALG_TESTED;
mask |= CRYPTO_ALG_TESTED;
}
larval = crypto_larval_lookup(name, type, mask);
if (IS_ERR(larval) || !crypto_is_larval(larval))
return larval;
ok = crypto_probing_notify(CRYPTO_MSG_ALG_REQUEST, larval);
if (ok == NOTIFY_STOP)
alg = crypto_larval_wait(larval);
else {
crypto_mod_put(larval);
alg = ERR_PTR(-ENOENT);
}
crypto_larval_kill(larval);
return alg;
}
EXPORT_SYMBOL_GPL(crypto_alg_mod_lookup);
static int crypto_init_ops(struct crypto_tfm *tfm, u32 type, u32 mask)
{
const struct crypto_type *type_obj = tfm->__crt_alg->cra_type;
if (type_obj)
return type_obj->init(tfm, type, mask);
switch (crypto_tfm_alg_type(tfm)) {
case CRYPTO_ALG_TYPE_CIPHER:
return crypto_init_cipher_ops(tfm);
case CRYPTO_ALG_TYPE_COMPRESS:
return crypto_init_compress_ops(tfm);
default:
break;
}
BUG();
return -EINVAL;
}
static void crypto_exit_ops(struct crypto_tfm *tfm)
{
const struct crypto_type *type = tfm->__crt_alg->cra_type;
if (type) {
if (tfm->exit)
tfm->exit(tfm);
return;
}
switch (crypto_tfm_alg_type(tfm)) {
case CRYPTO_ALG_TYPE_CIPHER:
crypto_exit_cipher_ops(tfm);
break;
case CRYPTO_ALG_TYPE_COMPRESS:
crypto_exit_compress_ops(tfm);
break;
default:
BUG();
}
}
static unsigned int crypto_ctxsize(struct crypto_alg *alg, u32 type, u32 mask)
{
const struct crypto_type *type_obj = alg->cra_type;
unsigned int len;
len = alg->cra_alignmask & ~(crypto_tfm_ctx_alignment() - 1);
if (type_obj)
return len + type_obj->ctxsize(alg, type, mask);
switch (alg->cra_flags & CRYPTO_ALG_TYPE_MASK) {
default:
BUG();
case CRYPTO_ALG_TYPE_CIPHER:
len += crypto_cipher_ctxsize(alg);
break;
case CRYPTO_ALG_TYPE_COMPRESS:
len += crypto_compress_ctxsize(alg);
break;
}
return len;
}
void crypto_shoot_alg(struct crypto_alg *alg)
{
down_write(&crypto_alg_sem);
alg->cra_flags |= CRYPTO_ALG_DYING;
up_write(&crypto_alg_sem);
}
EXPORT_SYMBOL_GPL(crypto_shoot_alg);
struct crypto_tfm *__crypto_alloc_tfm(struct crypto_alg *alg, u32 type,
u32 mask)
{
struct crypto_tfm *tfm = NULL;
unsigned int tfm_size;
int err = -ENOMEM;
tfm_size = sizeof(*tfm) + crypto_ctxsize(alg, type, mask);
tfm = kzalloc(tfm_size, GFP_KERNEL);
if (tfm == NULL)
goto out_err;
tfm->__crt_alg = alg;
err = crypto_init_ops(tfm, type, mask);
if (err)
goto out_free_tfm;
if (!tfm->exit && alg->cra_init && (err = alg->cra_init(tfm)))
goto cra_init_failed;
goto out;
cra_init_failed:
crypto_exit_ops(tfm);
out_free_tfm:
if (err == -EAGAIN)
crypto_shoot_alg(alg);
kfree(tfm);
out_err:
tfm = ERR_PTR(err);
out:
return tfm;
}
EXPORT_SYMBOL_GPL(__crypto_alloc_tfm);
/*
* crypto_alloc_base - Locate algorithm and allocate transform
* @alg_name: Name of algorithm
* @type: Type of algorithm
* @mask: Mask for type comparison
*
* This function should not be used by new algorithm types.
* Please use crypto_alloc_tfm instead.
*
* crypto_alloc_base() will first attempt to locate an already loaded
* algorithm. If that fails and the kernel supports dynamically loadable
* modules, it will then attempt to load a module of the same name or
* alias. If that fails it will send a query to any loaded crypto manager
* to construct an algorithm on the fly. A refcount is grabbed on the
* algorithm which is then associated with the new transform.
*
* The returned transform is of a non-determinate type. Most people
* should use one of the more specific allocation functions such as
* crypto_alloc_blkcipher.
*
* In case of error the return value is an error pointer.
*/
struct crypto_tfm *crypto_alloc_base(const char *alg_name, u32 type, u32 mask)
{
struct crypto_tfm *tfm;
int err;
for (;;) {
struct crypto_alg *alg;
alg = crypto_alg_mod_lookup(alg_name, type, mask);
if (IS_ERR(alg)) {
err = PTR_ERR(alg);
goto err;
}
tfm = __crypto_alloc_tfm(alg, type, mask);
if (!IS_ERR(tfm))
return tfm;
crypto_mod_put(alg);
err = PTR_ERR(tfm);
err:
if (err != -EAGAIN)
break;
if (signal_pending(current)) {
err = -EINTR;
break;
}
}
return ERR_PTR(err);
}
EXPORT_SYMBOL_GPL(crypto_alloc_base);
void *crypto_create_tfm(struct crypto_alg *alg,
const struct crypto_type *frontend)
{
char *mem;
struct crypto_tfm *tfm = NULL;
unsigned int tfmsize;
unsigned int total;
int err = -ENOMEM;
tfmsize = frontend->tfmsize;
total = tfmsize + sizeof(*tfm) + frontend->extsize(alg);
mem = kzalloc(total, GFP_KERNEL);
if (mem == NULL)
goto out_err;
tfm = (struct crypto_tfm *)(mem + tfmsize);
tfm->__crt_alg = alg;
err = frontend->init_tfm(tfm);
if (err)
goto out_free_tfm;
if (!tfm->exit && alg->cra_init && (err = alg->cra_init(tfm)))
goto cra_init_failed;
goto out;
cra_init_failed:
crypto_exit_ops(tfm);
out_free_tfm:
if (err == -EAGAIN)
crypto_shoot_alg(alg);
kfree(mem);
out_err:
mem = ERR_PTR(err);
out:
return mem;
}
EXPORT_SYMBOL_GPL(crypto_create_tfm);
struct crypto_alg *crypto_find_alg(const char *alg_name,
const struct crypto_type *frontend,
u32 type, u32 mask)
{
struct crypto_alg *(*lookup)(const char *name, u32 type, u32 mask) =
crypto_alg_mod_lookup;
if (frontend) {
type &= frontend->maskclear;
mask &= frontend->maskclear;
type |= frontend->type;
mask |= frontend->maskset;
if (frontend->lookup)
lookup = frontend->lookup;
}
return lookup(alg_name, type, mask);
}
EXPORT_SYMBOL_GPL(crypto_find_alg);
/*
* crypto_alloc_tfm - Locate algorithm and allocate transform
* @alg_name: Name of algorithm
* @frontend: Frontend algorithm type
* @type: Type of algorithm
* @mask: Mask for type comparison
*
* crypto_alloc_tfm() will first attempt to locate an already loaded
* algorithm. If that fails and the kernel supports dynamically loadable
* modules, it will then attempt to load a module of the same name or
* alias. If that fails it will send a query to any loaded crypto manager
* to construct an algorithm on the fly. A refcount is grabbed on the
* algorithm which is then associated with the new transform.
*
* The returned transform is of a non-determinate type. Most people
* should use one of the more specific allocation functions such as
* crypto_alloc_blkcipher.
*
* In case of error the return value is an error pointer.
*/
void *crypto_alloc_tfm(const char *alg_name,
const struct crypto_type *frontend, u32 type, u32 mask)
{
void *tfm;
int err;
for (;;) {
struct crypto_alg *alg;
alg = crypto_find_alg(alg_name, frontend, type, mask);
if (IS_ERR(alg)) {
err = PTR_ERR(alg);
goto err;
}
tfm = crypto_create_tfm(alg, frontend);
if (!IS_ERR(tfm))
return tfm;
crypto_mod_put(alg);
err = PTR_ERR(tfm);
err:
if (err != -EAGAIN)
break;
if (signal_pending(current)) {
err = -EINTR;
break;
}
}
return ERR_PTR(err);
}
EXPORT_SYMBOL_GPL(crypto_alloc_tfm);
/*
* crypto_destroy_tfm - Free crypto transform
* @mem: Start of tfm slab
* @tfm: Transform to free
*
* This function frees up the transform and any associated resources,
* then drops the refcount on the associated algorithm.
*/
void crypto_destroy_tfm(void *mem, struct crypto_tfm *tfm)
{
struct crypto_alg *alg;
if (unlikely(!mem))
return;
alg = tfm->__crt_alg;
if (!tfm->exit && alg->cra_exit)
alg->cra_exit(tfm);
crypto_exit_ops(tfm);
crypto_mod_put(alg);
kzfree(mem);
}
EXPORT_SYMBOL_GPL(crypto_destroy_tfm);
int crypto_has_alg(const char *name, u32 type, u32 mask)
{
int ret = 0;
struct crypto_alg *alg = crypto_alg_mod_lookup(name, type, mask);
if (!IS_ERR(alg)) {
crypto_mod_put(alg);
ret = 1;
}
return ret;
}
EXPORT_SYMBOL_GPL(crypto_has_alg);
MODULE_DESCRIPTION("Cryptographic core API");
MODULE_LICENSE("GPL");
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