From 96489c1c0b53131b0e1ec33e2060538379ad6152 Mon Sep 17 00:00:00 2001 From: Miquel Raynal Date: Thu, 16 Dec 2021 12:16:38 +0100 Subject: [PATCH] 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 Link: https://lore.kernel.org/linux-mtd/20211216111654.238086-13-miquel.raynal@bootlin.com --- drivers/mtd/nand/core.c | 10 ++++-- drivers/mtd/nand/ecc.c | 88 ++++++++++++++++++++++++++++++++++++++++++++++++ include/linux/mtd/nand.h | 28 +++++++++++++++ 3 files changed, 123 insertions(+), 3 deletions(-) diff --git a/drivers/mtd/nand/core.c b/drivers/mtd/nand/core.c index 416947f..ff34e3f 100644 --- a/drivers/mtd/nand/core.c +++ b/drivers/mtd/nand/core.c @@ -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; } diff --git a/drivers/mtd/nand/ecc.c b/drivers/mtd/nand/ecc.c index 6c43dfd..078f5ec 100644 --- a/drivers/mtd/nand/ecc.c +++ b/drivers/mtd/nand/ecc.c @@ -96,6 +96,12 @@ #include #include #include +#include +#include +#include + +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 "); MODULE_DESCRIPTION("Generic ECC engine"); diff --git a/include/linux/mtd/nand.h b/include/linux/mtd/nand.h index 32fc7ed..4ddd20f 100644 --- a/include/linux/mtd/nand.h +++ b/include/linux/mtd/nand.h @@ -264,11 +264,35 @@ struct nand_ecc_engine_ops { }; /** + * 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); -- 2.7.4