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mtd: nand: ecc: Add infrastructure to support hardware engines 

Add the necessary helpers to register/unregister hardware ECC engines
that will be called from ECC engine drivers.

Also add helpers to get the right engine from the user
perspective. Keep a reference of the in use ECC engine in order to
prevent modules to be unloaded. Put the reference when the engine gets
retired.

A static list of hardware (only) ECC engines is setup to keep track of
the registered engines.

Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Link: https://lore.kernel.org/linux-mtd/20211216111654.238086-13-miquel.raynal@bootlin.com
This commit is contained in:
Miquel Raynal 2021-12-16 12:16:38 +01:00
parent 1d46963d45
commit 96489c1c0b
3 changed files with 123 additions and 3 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

10
drivers/mtd/nand/core.c
View File

@ -235,7 +235,9 @@ static int nanddev_get_ecc_engine(struct nand_device *nand)
nand->ecc.engine = nand_ecc_get_on_die_hw_engine(nand);
break;
case NAND_ECC_ENGINE_TYPE_ON_HOST:
pr_err("On-host hardware ECC engines not supported yet\n");
nand->ecc.engine = nand_ecc_get_on_host_hw_engine(nand);
if (PTR_ERR(nand->ecc.engine) == -EPROBE_DEFER)
return -EPROBE_DEFER;
break;
default:
pr_err("Missing ECC engine type\n");
@ -255,7 +257,7 @@ static int nanddev_put_ecc_engine(struct nand_device *nand)
{
switch (nand->ecc.ctx.conf.engine_type) {
case NAND_ECC_ENGINE_TYPE_ON_HOST:
pr_err("On-host hardware ECC engines not supported yet\n");
nand_ecc_put_on_host_hw_engine(nand);
break;
case NAND_ECC_ENGINE_TYPE_NONE:
case NAND_ECC_ENGINE_TYPE_SOFT:
@ -300,7 +302,9 @@ int nanddev_ecc_engine_init(struct nand_device *nand)
/* Look for the ECC engine to use */
ret = nanddev_get_ecc_engine(nand);
if (ret) {
pr_err("No ECC engine found\n");
if (ret != -EPROBE_DEFER)
pr_err("No ECC engine found\n");
return ret;
}

88
drivers/mtd/nand/ecc.c
View File

@ -96,6 +96,12 @@
#include <linux/module.h>
#include <linux/mtd/nand.h>
#include <linux/slab.h>
#include <linux/of.h>
#include <linux/of_device.h>
#include <linux/of_platform.h>
static LIST_HEAD(on_host_hw_engines);
static DEFINE_MUTEX(on_host_hw_engines_mutex);
/**
* nand_ecc_init_ctx - Init the ECC engine context
@ -611,6 +617,88 @@ struct nand_ecc_engine *nand_ecc_get_on_die_hw_engine(struct nand_device *nand)
}
EXPORT_SYMBOL(nand_ecc_get_on_die_hw_engine);
int nand_ecc_register_on_host_hw_engine(struct nand_ecc_engine *engine)
{
struct nand_ecc_engine *item;
if (!engine)
return -EINVAL;
/* Prevent multiple registrations of one engine */
list_for_each_entry(item, &on_host_hw_engines, node)
if (item == engine)
return 0;
mutex_lock(&on_host_hw_engines_mutex);
list_add_tail(&engine->node, &on_host_hw_engines);
mutex_unlock(&on_host_hw_engines_mutex);
return 0;
}
EXPORT_SYMBOL(nand_ecc_register_on_host_hw_engine);
int nand_ecc_unregister_on_host_hw_engine(struct nand_ecc_engine *engine)
{
if (!engine)
return -EINVAL;
mutex_lock(&on_host_hw_engines_mutex);
list_del(&engine->node);
mutex_unlock(&on_host_hw_engines_mutex);
return 0;
}
EXPORT_SYMBOL(nand_ecc_unregister_on_host_hw_engine);
static struct nand_ecc_engine *nand_ecc_match_on_host_hw_engine(struct device *dev)
{
struct nand_ecc_engine *item;
list_for_each_entry(item, &on_host_hw_engines, node)
if (item->dev == dev)
return item;
return NULL;
}
struct nand_ecc_engine *nand_ecc_get_on_host_hw_engine(struct nand_device *nand)
{
struct nand_ecc_engine *engine = NULL;
struct device *dev = &nand->mtd.dev;
struct platform_device *pdev;
struct device_node *np;
if (list_empty(&on_host_hw_engines))
return NULL;
/* Check for an explicit nand-ecc-engine property */
np = of_parse_phandle(dev->of_node, "nand-ecc-engine", 0);
if (np) {
pdev = of_find_device_by_node(np);
if (!pdev)
return ERR_PTR(-EPROBE_DEFER);
engine = nand_ecc_match_on_host_hw_engine(&pdev->dev);
platform_device_put(pdev);
of_node_put(np);
if (!engine)
return ERR_PTR(-EPROBE_DEFER);
}
if (engine)
get_device(engine->dev);
return engine;
}
EXPORT_SYMBOL(nand_ecc_get_on_host_hw_engine);
void nand_ecc_put_on_host_hw_engine(struct nand_device *nand)
{
put_device(nand->ecc.engine->dev);
}
EXPORT_SYMBOL(nand_ecc_put_on_host_hw_engine);
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Miquel Raynal <miquel.raynal@bootlin.com>");
MODULE_DESCRIPTION("Generic ECC engine");

28
include/linux/mtd/nand.h
View File

@ -263,12 +263,36 @@ struct nand_ecc_engine_ops {
struct nand_page_io_req *req);
};
/**
* enum nand_ecc_engine_integration - How the NAND ECC engine is integrated
* @NAND_ECC_ENGINE_INTEGRATION_INVALID: Invalid value
* @NAND_ECC_ENGINE_INTEGRATION_PIPELINED: Pipelined engine, performs on-the-fly
* correction, does not need to copy
* data around
* @NAND_ECC_ENGINE_INTEGRATION_EXTERNAL: External engine, needs to bring the
* data into its own area before use
*/
enum nand_ecc_engine_integration {
NAND_ECC_ENGINE_INTEGRATION_INVALID,
NAND_ECC_ENGINE_INTEGRATION_PIPELINED,
NAND_ECC_ENGINE_INTEGRATION_EXTERNAL,
};
/**
* struct nand_ecc_engine - ECC engine abstraction for NAND devices
* @dev: Host device
* @node: Private field for registration time
* @ops: ECC engine operations
* @integration: How the engine is integrated with the host
* (only relevant on %NAND_ECC_ENGINE_TYPE_ON_HOST engines)
* @priv: Private data
*/
struct nand_ecc_engine {
struct device *dev;
struct list_head node;
struct nand_ecc_engine_ops *ops;
enum nand_ecc_engine_integration integration;
void *priv;
};
void of_get_nand_ecc_user_config(struct nand_device *nand);
@ -279,8 +303,12 @@ int nand_ecc_prepare_io_req(struct nand_device *nand,
int nand_ecc_finish_io_req(struct nand_device *nand,
struct nand_page_io_req *req);
bool nand_ecc_is_strong_enough(struct nand_device *nand);
int nand_ecc_register_on_host_hw_engine(struct nand_ecc_engine *engine);
int nand_ecc_unregister_on_host_hw_engine(struct nand_ecc_engine *engine);
struct nand_ecc_engine *nand_ecc_get_sw_engine(struct nand_device *nand);
struct nand_ecc_engine *nand_ecc_get_on_die_hw_engine(struct nand_device *nand);
struct nand_ecc_engine *nand_ecc_get_on_host_hw_engine(struct nand_device *nand);
void nand_ecc_put_on_host_hw_engine(struct nand_device *nand);
#if IS_ENABLED(CONFIG_MTD_NAND_ECC_SW_HAMMING)
struct nand_ecc_engine *nand_ecc_sw_hamming_get_engine(void);