Re: [PATCH 3/3] mtd: partitions: Add OF support to RedBoot partitions

[Boris Brezillon <boris.brezillon@bootlin.com>]

On Fri, 19 Oct 2018 09:06:22 +0200
Linus Walleij <linus.walleij@linaro.org> wrote:

> This adds device tree support for RedBoot partitioning. We
> read out the FIS directory block information from the device
> tree and then parse the partition table from there.
> 
> Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
> ---
>  drivers/mtd/parsers/redboot.c | 35 ++++++++++++++++++++++++++++++++++-
>  1 file changed, 34 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/mtd/parsers/redboot.c b/drivers/mtd/parsers/redboot.c
> index 7623ac5fc586..fb816825aa19 100644
> --- a/drivers/mtd/parsers/redboot.c
> +++ b/drivers/mtd/parsers/redboot.c
> @@ -25,7 +25,7 @@
>  #include <linux/slab.h>
>  #include <linux/init.h>
>  #include <linux/vmalloc.h>
> -
> +#include <linux/of.h>
>  #include <linux/mtd/mtd.h>
>  #include <linux/mtd/partitions.h>
>  #include <linux/module.h>
> @@ -56,6 +56,31 @@ static inline int redboot_checksum(struct fis_image_desc *img)
>  	return 1;
>  }
>  
> +#ifdef CONFIG_OF
> +static void parse_redboot_of(struct mtd_info *master)
> +{
> +	struct device_node *np;
> +	u32 dirblock;
> +	int ret;
> +
> +	np = mtd_get_of_node(master);
> +	if (!np)
> +		return;
> +	ret = of_property_read_u32(np, "fis-index-block", &dirblock);
> +	if (ret)
> +		return;
> +	/*
> +	 * Assign the block found in the device tree to the local
> +	 * directory block pointer.
> +	 */
> +	directory = dirblock;
> +}
> +#else
> +static void parse_redboot_of(struct mtd_info *master)
> +{
> +}
> +#endif
> +
>  static int parse_redboot_partitions(struct mtd_info *master,
>  				    const struct mtd_partition **pparts,
>  				    struct mtd_part_parser_data *data)
> @@ -75,6 +100,7 @@ static int parse_redboot_partitions(struct mtd_info *master,
>  #ifdef CONFIG_MTD_REDBOOT_PARTS_UNALLOCATED
>  	static char nullstring[] = "unallocated";
>  #endif
> +	parse_redboot_of(master);
>  
>  	if ( directory < 0 ) {
>  		offset = master->size + directory * master->erasesize;
> @@ -289,9 +315,16 @@ static int parse_redboot_partitions(struct mtd_info *master,
>  	return ret;
>  }
>  
> +static const struct of_device_id mtd_parser_redboot_of_match_table[] = {
> +	{ .compatible = "redboot-fis" },
> +	{},
> +};
> +MODULE_DEVICE_TABLE(of, mtd_parser_trx_of_match_table);

You might want to have this match table definition enclosed in a #ifdef
CONFIG_OF section...

> +
>  static struct mtd_part_parser redboot_parser = {
>  	.parse_fn = parse_redboot_partitions,
>  	.name = "RedBoot",
> +	.of_match_table = mtd_parser_redboot_of_match_table,

... and use of_match_ptr(mtd_parser_redboot_of_match_table) here.

I'm proposing that to make it consistent with the
approach you've taken for the parse_redboot_of() function.

Alternatively, you could just drop the #ifdef CONFIG_OF section around
parse_redboot_of() (there's already a dummy of_property_read_u32()
func returning -ENOSYS when CONFIG_OF is not set, so it should work
just fine).

>  };
>  module_mtd_part_parser(redboot_parser);
>