Re: [PATCH v2] mtd: rawnand: gpmi: add debugfs entry for BCH geometry

On Wed, Jul 29, 2026 at 02:22:20PM -0500, [email protected] wrote:
> From: Han Xu <[email protected]>
>
> Export the BCH geometry parameters via debugfs to aid debugging and
> provide the necessary information for legacy kobs-ng tool. The debugfs
> directory "gpmi-nand" is created under the root debugfs tree, exposing:
>
> bch_geometry  - blob containing the struct bch_geometry fields
> raw_mode      - flag indicating raw mode status
>
> The implementation is guarded with #ifdef CONFIG_DEBUG_FS to avoid
> build failures when debugfs is disabled.
>
> Signed-off-by: Han Xu <[email protected]>
> ---
> Changes in v2:
> - Move dbg_root and dbg_bch_geo into struct gpmi_nand_data to fix
>   use-after-free on device unbind.
> - Replace debugfs_create_file_full() with debugfs_create_bool() to
>   expose the raw_mode flag.
> - Register a devm cleanup action to call debugfs_remove_recursive() on
>   driver removal.
>
> To: Han Xu <[email protected]>
> To: Miquel Raynal <[email protected]>
> To: Richard Weinberger <[email protected]>
> To: Vignesh Raghavendra <[email protected]>
> Cc: [email protected]
> Cc: [email protected]
> Cc: [email protected]
> ---

Reviewed-by: Frank Li <[email protected]>

>  drivers/mtd/nand/raw/gpmi-nand/gpmi-nand.c | 29 +++++++++++++++++++++++++++++
>  drivers/mtd/nand/raw/gpmi-nand/gpmi-nand.h |  6 ++++++
>  2 files changed, 35 insertions(+)
>
> diff --git a/drivers/mtd/nand/raw/gpmi-nand/gpmi-nand.c b/drivers/mtd/nand/raw/gpmi-nand/gpmi-nand.c
> index c1f766cb225aa..527165ccc839d 100644
> --- a/drivers/mtd/nand/raw/gpmi-nand/gpmi-nand.c
> +++ b/drivers/mtd/nand/raw/gpmi-nand/gpmi-nand.c
> @@ -7,6 +7,7 @@
>   */
>  #include <linux/cleanup.h>
>  #include <linux/clk.h>
> +#include <linux/debugfs.h>
bch_remove_debugfs>  #include <linux/delay.h>
>  #include <linux/slab.h>
>  #include <linux/sched/task_stack.h>
> @@ -732,6 +733,31 @@ static int common_nfc_set_geometry(struct gpmi_nand_data *this)
>  	return err;
>  }
>
> +#ifdef CONFIG_DEBUG_FS
> +static void bch_remove_debugfs(void *data)
> +{
> +	struct gpmi_nand_data *this = data;
> +
> +	debugfs_remove_recursive(this->dbg_root);
> +	this->dbg_root = NULL;
> +}
> +
> +static void bch_create_debugfs(struct gpmi_nand_data *this)
> +{
> +	struct bch_geometry *bch_geo = &this->bch_geometry;
> +
> +	this->dbg_root = debugfs_create_dir("gpmi-nand", NULL);
> +	this->dbg_bch_geo.data = (void *)bch_geo;
> +	this->dbg_bch_geo.size = sizeof(struct bch_geometry);
> +	this->raw_mode = true;
> +	debugfs_create_blob("bch_geometry", 0444, this->dbg_root, &this->dbg_bch_geo);
> +	debugfs_create_bool("raw_mode", 0444, this->dbg_root, &this->raw_mode);
> +	devm_add_action_or_reset(this->dev, bch_remove_debugfs, this);
> +}
> +#else
> +static void bch_create_debugfs(struct gpmi_nand_data *this) {}
> +#endif /* CONFIG_DEBUG_FS */
> +
>  /* Configures the geometry for BCH.  */
>  static int bch_set_geometry(struct gpmi_nand_data *this)
>  {
> @@ -2282,6 +2308,9 @@ static int gpmi_init_last(struct gpmi_nand_data *this)
>  	if (ret)
>  		return ret;
>
> +	/* save BCH geometry to debugfs if CONFIG_DEBUG_FS is enabled */
> +	bch_create_debugfs(this);
> +
>  	/* Init the nand_ecc_ctrl{} */
>  	ecc->read_page	= gpmi_ecc_read_page;
>  	ecc->write_page	= gpmi_ecc_write_page;
> diff --git a/drivers/mtd/nand/raw/gpmi-nand/gpmi-nand.h b/drivers/mtd/nand/raw/gpmi-nand/gpmi-nand.h
> index 3e9bc985e44a3..80c32efbaef86 100644
> --- a/drivers/mtd/nand/raw/gpmi-nand/gpmi-nand.h
> +++ b/drivers/mtd/nand/raw/gpmi-nand/gpmi-nand.h
> @@ -161,6 +161,12 @@ struct gpmi_nand_data {
>  #define DMA_CHANS		8
>  	struct dma_chan		*dma_chans[DMA_CHANS];
>  	struct completion	dma_done;
> +
> +#ifdef CONFIG_DEBUG_FS
> +	struct			dentry *dbg_root;
> +	struct			debugfs_blob_wrapper dbg_bch_geo;
> +	bool			raw_mode;
> +#endif
>  };
>
>  /* BCH : Status Block Completion Codes */
>
> ---
> base-commit: f97bdc8ec1dc7b33781a702eeba55326c206be56
> change-id: 20260727-nand_debugfs-74d6d6ba52df
>
> Best regards,
> --
> Han Xu <[email protected]>
>
>

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