Re: [PATCH v3 3/3] mtd: s3c2410: parse the device configuration from OF node

[Boris Brezillon <boris.brezillon@free-electrons.com>]

On Thu, 20 Oct 2016 19:42:46 -0200
Sergio Prado <sergio.prado@e-labworks.com> wrote:

> Allows configuring Samsung's s3c2410 memory controller using a
> devicetree.
> 
> Signed-off-by: Sergio Prado <sergio.prado@e-labworks.com>
> ---
>  drivers/mtd/nand/s3c2410.c                     | 158 ++++++++++++++++++++++---
>  include/linux/platform_data/mtd-nand-s3c2410.h |   1 +
>  2 files changed, 143 insertions(+), 16 deletions(-)
> 
> diff --git a/drivers/mtd/nand/s3c2410.c b/drivers/mtd/nand/s3c2410.c
> index 371db0d48135..ec170be881bc 100644
> --- a/drivers/mtd/nand/s3c2410.c
> +++ b/drivers/mtd/nand/s3c2410.c
> @@ -39,6 +39,8 @@
>  #include <linux/slab.h>
>  #include <linux/clk.h>
>  #include <linux/cpufreq.h>
> +#include <linux/of.h>
> +#include <linux/of_device.h>
>  
>  #include <linux/mtd/mtd.h>
>  #include <linux/mtd/nand.h>
> @@ -185,6 +187,22 @@ struct s3c2410_nand_info {
>  #endif
>  };
>  
> +struct s3c24XX_nand_devtype_data {
> +	enum s3c_cpu_type type;
> +};
> +
> +static const struct s3c24XX_nand_devtype_data s3c2410_nand_devtype_data = {
> +	.type = TYPE_S3C2410,
> +};
> +
> +static const struct s3c24XX_nand_devtype_data s3c2412_nand_devtype_data = {
> +	.type = TYPE_S3C2412,
> +};
> +
> +static const struct s3c24XX_nand_devtype_data s3c2440_nand_devtype_data = {
> +	.type = TYPE_S3C2440,
> +};
> +
>  /* conversion functions */
>  
>  static struct s3c2410_nand_mtd *s3c2410_nand_mtd_toours(struct mtd_info *mtd)
> @@ -794,6 +812,30 @@ static int s3c2410_nand_add_partition(struct s3c2410_nand_info *info,
>  	return -ENODEV;
>  }
>  
> +static int s3c2410_nand_setup_data_interface(struct mtd_info *mtd,
> +					     const struct nand_data_interface *conf,
> +					     bool check_only)
> +{
> +	struct s3c2410_nand_info *info = s3c2410_nand_mtd_toinfo(mtd);
> +	struct s3c2410_platform_nand *pdata = info->platform;
> +	const struct nand_sdr_timings *timings;
> +	int tacls;
> +
> +	timings = nand_get_sdr_timings(conf);
> +	if (IS_ERR(timings))
> +		return -ENOTSUPP;
> +
> +	tacls = timings->tCLS_min - timings->tWP_min;
> +	if (tacls < 0)
> +		tacls = 0;
> +
> +	pdata->tacls  = DIV_ROUND_UP(tacls, 1000);
> +	pdata->twrph0 = DIV_ROUND_UP(timings->tWP_min, 1000);
> +	pdata->twrph1 = DIV_ROUND_UP(timings->tCLH_min, 1000);

You seem to only apply the timings in s3c2410_nand_setrate(), which is
only called at probe time or on a cpufreq even, but the core can change
timings at runtime (this is what happens each time you reset the chip).

To support that you have 2 options:
 - apply the timings in ->select_chip()
 - apply the timings here

> +
> +	return 0;
> +}
> +
>  /**
>   * s3c2410_nand_init_chip - initialise a single instance of an chip
>   * @info: The base NAND controller the chip is on.
> @@ -808,9 +850,12 @@ static void s3c2410_nand_init_chip(struct s3c2410_nand_info *info,
>  				   struct s3c2410_nand_mtd *nmtd,
>  				   struct s3c2410_nand_set *set)
>  {
> +	struct device_node *np = info->device->of_node;
>  	struct nand_chip *chip = &nmtd->chip;
>  	void __iomem *regs = info->regs;
>  
> +	nand_set_flash_node(chip, set->of_node);
> +
>  	chip->write_buf    = s3c2410_nand_write_buf;
>  	chip->read_buf     = s3c2410_nand_read_buf;
>  	chip->select_chip  = s3c2410_nand_select_chip;
> @@ -819,6 +864,13 @@ static void s3c2410_nand_init_chip(struct s3c2410_nand_info *info,
>  	chip->options	   = set->options;
>  	chip->controller   = &info->controller;
>  
> +	/*
> +	 * let's keep behavior unchanged for legacy boards booting via pdata and
> +	 * auto-detect timings only when booting with a device tree.
> +	 */
> +	if (np)
> +		chip->setup_data_interface = s3c2410_nand_setup_data_interface;
> +
>  	switch (info->cpu_type) {
>  	case TYPE_S3C2410:
>  		chip->IO_ADDR_W = regs + S3C2410_NFDATA;
> @@ -859,12 +911,9 @@ static void s3c2410_nand_init_chip(struct s3c2410_nand_info *info,
>  	chip->ecc.mode = info->platform->ecc_mode;
>  
>  	/* If you use u-boot BBT creation code, specifying this flag will
> -	 * let the kernel fish out the BBT from the NAND, and also skip the
> -	 * full NAND scan that can take 1/2s or so. Little things... */
> -	if (set->flash_bbt) {
> +	 * let the kernel fish out the BBT from the NAND */
> +	if (set->flash_bbt)
>  		chip->bbt_options |= NAND_BBT_USE_FLASH;
> -		chip->options |= NAND_SKIP_BBTSCAN;
> -	}
>  }
>  
>  /**
> @@ -943,6 +992,77 @@ static int s3c2410_nand_update_chip(struct s3c2410_nand_info *info,
>  		return -EINVAL;
>  	}
>  
> +	if (chip->bbt_options & NAND_BBT_USE_FLASH)
> +		chip->options |= NAND_SKIP_BBTSCAN;
> +
> +	return 0;
> +}
> +
> +static const struct of_device_id s3c24xx_nand_dt_ids[] = {
> +	{
> +		.compatible = "samsung,s3c2410-nand",
> +		.data = &s3c2410_nand_devtype_data,
> +	}, {
> +		.compatible = "samsung,s3c2412-nand", /* also compatible with s3c6400 */
> +		.data = &s3c2412_nand_devtype_data,
> +	}, {
> +		.compatible = "samsung,s3c2440-nand",
> +		.data = &s3c2440_nand_devtype_data,
> +	},
> +	{ /* sentinel */ }
> +};
> +MODULE_DEVICE_TABLE(of, s3c24xx_nand_dt_ids);
> +
> +static int s3c24xx_nand_probe_dt(struct platform_device *pdev)
> +{
> +	const struct s3c24XX_nand_devtype_data *devtype_data;
> +	struct s3c2410_platform_nand *pdata;
> +	struct s3c2410_nand_info *info = platform_get_drvdata(pdev);
> +	struct device_node *np = pdev->dev.of_node, *child;
> +	struct s3c2410_nand_set *sets;
> +
> +	devtype_data = of_device_get_match_data(&pdev->dev);
> +	if (!devtype_data)
> +		return -ENODEV;
> +
> +	info->cpu_type = devtype_data->type;
> +
> +	pdata = devm_kzalloc(&pdev->dev, sizeof(*pdata), GFP_KERNEL);
> +	if (!pdata)
> +		return -ENOMEM;
> +
> +	pdev->dev.platform_data = pdata;
> +
> +	pdata->nr_sets = of_get_child_count(np);
> +	if (!pdata->nr_sets)
> +		return 0;
> +
> +	sets = devm_kzalloc(&pdev->dev, sizeof(*sets) * pdata->nr_sets, GFP_KERNEL);
> +	if (!sets)
> +		return -ENOMEM;
> +
> +	pdata->sets = sets;
> +
> +	for_each_available_child_of_node(np, child) {
> +
> +		sets->name = (char *)child->name;
> +		sets->of_node = child;
> +		sets->nr_chips = 1;
> +
> +		of_node_get(child);
> +
> +		sets++;
> +	}
> +
> +	return 0;
> +}
> +
> +static int s3c24xx_nand_probe_pdata(struct platform_device *pdev)
> +{
> +	struct s3c2410_nand_info *info = platform_get_drvdata(pdev);
> +
> +	info->cpu_type = platform_get_device_id(pdev)->driver_data;
> +
>  	return 0;
>  }
>  
> @@ -955,8 +1075,7 @@ static int s3c2410_nand_update_chip(struct s3c2410_nand_info *info,
>  */
>  static int s3c24xx_nand_probe(struct platform_device *pdev)
>  {
> -	struct s3c2410_platform_nand *plat = to_nand_plat(pdev);
> -	enum s3c_cpu_type cpu_type;
> +	struct s3c2410_platform_nand *plat;
>  	struct s3c2410_nand_info *info;
>  	struct s3c2410_nand_mtd *nmtd;
>  	struct s3c2410_nand_set *sets;
> @@ -966,8 +1085,6 @@ static int s3c24xx_nand_probe(struct platform_device *pdev)
>  	int nr_sets;
>  	int setno;
>  
> -	cpu_type = platform_get_device_id(pdev)->driver_data;
> -
>  	info = devm_kzalloc(&pdev->dev, sizeof(*info), GFP_KERNEL);
>  	if (info == NULL) {
>  		err = -ENOMEM;
> @@ -989,6 +1106,16 @@ static int s3c24xx_nand_probe(struct platform_device *pdev)
>  
>  	s3c2410_nand_clk_set_state(info, CLOCK_ENABLE);
>  
> +	if (pdev->dev.of_node)
> +		err = s3c24xx_nand_probe_dt(pdev);
> +	else
> +		err = s3c24xx_nand_probe_pdata(pdev);
> +
> +	if (err)
> +		goto exit_error;
> +
> +	plat = to_nand_plat(pdev);
> +
>  	/* allocate and map the resource */
>  
>  	/* currently we assume we have the one resource */
> @@ -997,7 +1124,6 @@ static int s3c24xx_nand_probe(struct platform_device *pdev)
>  
>  	info->device	= &pdev->dev;
>  	info->platform	= plat;
> -	info->cpu_type	= cpu_type;
>  
>  	info->regs = devm_ioremap_resource(&pdev->dev, res);
>  	if (IS_ERR(info->regs)) {
> @@ -1007,12 +1133,6 @@ static int s3c24xx_nand_probe(struct platform_device *pdev)
>  
>  	dev_dbg(&pdev->dev, "mapped registers at %p\n", info->regs);
>  
> -	/* initialise the hardware */
> -
> -	err = s3c2410_nand_inithw(info);
> -	if (err != 0)
> -		goto exit_error;
> -
>  	sets = (plat != NULL) ? plat->sets : NULL;
>  	nr_sets = (plat != NULL) ? plat->nr_sets : 1;
>  
> @@ -1056,6 +1176,11 @@ static int s3c24xx_nand_probe(struct platform_device *pdev)
>  			sets++;
>  	}
>  
> +	/* initialise the hardware */
> +	err = s3c2410_nand_inithw(info);
> +	if (err != 0)
> +		goto exit_error;
> +
>  	err = s3c2410_nand_cpufreq_register(info);
>  	if (err < 0) {
>  		dev_err(&pdev->dev, "failed to init cpufreq support\n");
> @@ -1156,6 +1281,7 @@ static int s3c24xx_nand_resume(struct platform_device *dev)
>  	.id_table	= s3c24xx_driver_ids,
>  	.driver		= {
>  		.name	= "s3c24xx-nand",
> +		.of_match_table = s3c24xx_nand_dt_ids,
>  	},
>  };
>  
> diff --git a/include/linux/platform_data/mtd-nand-s3c2410.h b/include/linux/platform_data/mtd-nand-s3c2410.h
> index 729af13d1773..f01659026b26 100644
> --- a/include/linux/platform_data/mtd-nand-s3c2410.h
> +++ b/include/linux/platform_data/mtd-nand-s3c2410.h
> @@ -40,6 +40,7 @@ struct s3c2410_nand_set {
>  	char			*name;
>  	int			*nr_map;
>  	struct mtd_partition	*partitions;
> +	struct device_node	*of_node;
>  };
>  
>  struct s3c2410_platform_nand {