Commit 6161b39a authored by Geert Uytterhoeven's avatar Geert Uytterhoeven
Browse files

pinctrl: sh-pfc: Validate pinmux tables at runtime when debugging 



Perform some basic sanity checks on all built-in pinmux tables when
DEBUG is defined, to help catching bugs early.

For now the following checks are included:
  - Check register and field widths in descriptors for config registers
    with variable-width fields,
  - Check relations between pin groups and functions:
      - All pin functions must refer to existing pin groups,
      - All pin groups must be referred to by a pin function,
      - Warn if a pin group is referred to by multiple pin functions
	(which is OK for backwards-compatibility aliases),
  - Provide suggestions for reducing table sizes: reserved fields of
    more than 3 bits can better be split in smaller subfields, as the
    storage need is proportional to the square of the width of the
    (sub)field,

Note that a dummy non-matching entry is added to the DT match table for
checking r8a7795es1_pinmux_info, as R-Car H3 ES1.0 is matched using
soc_device_match() in r8a7795_pinmux_init(), instead of by the DT match
table.

Signed-off-by: default avatarGeert Uytterhoeven <geert+renesas@glider.be>
Reviewed-by: default avatarSimon Horman <horms+renesas@verge.net.au>
parent d92ee9cf

drivers/pinctrl/sh-pfc/core.c

+124 −0
Original line number Diff line number Diff line
@@ -571,6 +571,13 @@ static const struct of_device_id sh_pfc_of_table[] = { 
		.compatible = "renesas,pfc-r8a7795",

		.data = &r8a7795_pinmux_info,

	},

#ifdef DEBUG

	{

		/* For sanity checks only (nothing matches against this) */

		.compatible = "renesas,pfc-r8a77950",	/* R-Car H3 ES1.0 */

		.data = &r8a7795es1_pinmux_info,

	},

#endif /* DEBUG */

#endif

#ifdef CONFIG_PINCTRL_PFC_R8A7796

	{
@@ -709,6 +716,122 @@ static int sh_pfc_suspend_init(struct sh_pfc *pfc) { return 0; } 
#define DEV_PM_OPS	NULL

#endif /* CONFIG_PM_SLEEP && CONFIG_ARM_PSCI_FW */



#ifdef DEBUG

static bool is0s(const u16 *enum_ids, unsigned int n)

{

	unsigned int i;



	for (i = 0; i < n; i++)

		if (enum_ids[i])

			return false;



	return true;

}



static unsigned int sh_pfc_errors;

static unsigned int sh_pfc_warnings;



static void sh_pfc_check_cfg_reg(const char *drvname,

				 const struct pinmux_cfg_reg *cfg_reg)

{

	unsigned int i, n, rw, fw;



	if (cfg_reg->field_width) {

		/* Checked at build time */

		return;

	}



	for (i = 0, n = 0, rw = 0; (fw = cfg_reg->var_field_width[i]); i++) {

		if (fw > 3 && is0s(&cfg_reg->enum_ids[n], 1 << fw)) {

			pr_warn("%s: reg 0x%x: reserved field [%u:%u] can be split to reduce table size\n",

				drvname, cfg_reg->reg, rw, rw + fw - 1);

			sh_pfc_warnings++;

		}

		n += 1 << fw;

		rw += fw;

	}



	if (rw != cfg_reg->reg_width) {

		pr_err("%s: reg 0x%x: var_field_width declares %u instead of %u bits\n",

		       drvname, cfg_reg->reg, rw, cfg_reg->reg_width);

		sh_pfc_errors++;

	}

}



static void sh_pfc_check_info(const struct sh_pfc_soc_info *info)

{

	const struct sh_pfc_function *func;

	const char *drvname = info->name;

	unsigned int *refcnts;

	unsigned int i, j, k;



	pr_info("Checking %s\n", drvname);



	/* Check groups and functions */

	refcnts = kcalloc(info->nr_groups, sizeof(*refcnts), GFP_KERNEL);

	if (!refcnts)

		return;



	for (i = 0; i < info->nr_functions; i++) {

		func = &info->functions[i];

		for (j = 0; j < func->nr_groups; j++) {

			for (k = 0; k < info->nr_groups; k++) {

				if (!strcmp(func->groups[j],

					    info->groups[k].name)) {

					refcnts[k]++;

					break;

				}

			}



			if (k == info->nr_groups) {

				pr_err("%s: function %s: group %s not found\n",

				       drvname, func->name, func->groups[j]);

				sh_pfc_errors++;

			}

		}

	}



	for (i = 0; i < info->nr_groups; i++) {

		if (!refcnts[i]) {

			pr_err("%s: orphan group %s\n", drvname,

			       info->groups[i].name);

			sh_pfc_errors++;

		} else if (refcnts[i] > 1) {

			pr_err("%s: group %s referred by %u functions\n",

			       drvname, info->groups[i].name, refcnts[i]);

			sh_pfc_warnings++;

		}

	}



	kfree(refcnts);



	/* Check config register descriptions */

	for (i = 0; info->cfg_regs && info->cfg_regs[i].reg; i++)

		sh_pfc_check_cfg_reg(drvname, &info->cfg_regs[i]);

}



static void sh_pfc_check_driver(const struct platform_driver *pdrv)

{

	unsigned int i;



	pr_warn("Checking builtin pinmux tables\n");



	for (i = 0; pdrv->id_table[i].name[0]; i++)

		sh_pfc_check_info((void *)pdrv->id_table[i].driver_data);



#ifdef CONFIG_OF

	for (i = 0; pdrv->driver.of_match_table[i].compatible[0]; i++)

		sh_pfc_check_info(pdrv->driver.of_match_table[i].data);

#endif



	pr_warn("Detected %u errors and %u warnings\n", sh_pfc_errors,

		sh_pfc_warnings);

}



#else /* !DEBUG */

static inline void sh_pfc_check_driver(struct platform_driver *pdrv) {}

#endif /* !DEBUG */



static int sh_pfc_probe(struct platform_device *pdev)

{

#ifdef CONFIG_OF
@@ -840,6 +963,7 @@ static struct platform_driver sh_pfc_driver = { 


static int __init sh_pfc_init(void)

{

	sh_pfc_check_driver(&sh_pfc_driver);

	return platform_driver_register(&sh_pfc_driver);

}

postcore_initcall(sh_pfc_init);

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