Commit 96489c1c authored by Miquel Raynal's avatar Miquel Raynal
Browse files

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: default avatarMiquel Raynal <miquel.raynal@bootlin.com>
Link: https://lore.kernel.org/linux-mtd/20211216111654.238086-13-miquel.raynal@bootlin.com
parent 1d46963d

drivers/mtd/nand/core.c

+7 −3
Original line number Diff line number Diff line
@@ -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) {

		if (ret != -EPROBE_DEFER)

			pr_err("No ECC engine found\n");



		return ret;

	}

drivers/mtd/nand/ecc.c

+88 −0
Original line number Diff line number Diff line
@@ -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");

include/linux/mtd/nand.h

+28 −0
Original line number Diff line number Diff line
@@ -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);