[PATCH/RFC 4.19.y-cip 02/41] pinctrl: sh-pfc: Validate pinmux tables at runtime when debugging


Fabrizio Castro <fabrizio.castro@...>
 

From: Geert Uytterhoeven <geert+renesas@...>

commit 6161b39a14380815f22851c753c00acf81cfa62a upstream.

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: Geert Uytterhoeven <geert+renesas@...>
Reviewed-by: Simon Horman <horms+renesas@...>
Signed-off-by: Fabrizio Castro <fabrizio.castro@...>
---
drivers/pinctrl/sh-pfc/core.c | 124 ++++++++++++++++++++++++++++++++++++++++++
1 file changed, 124 insertions(+)

diff --git a/drivers/pinctrl/sh-pfc/core.c b/drivers/pinctrl/sh-pfc/core.c
index 310b0dd..2c8c7b2 100644
--- a/drivers/pinctrl/sh-pfc/core.c
+++ b/drivers/pinctrl/sh-pfc/core.c
@@ -568,6 +568,13 @@ 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
{
@@ -706,6 +713,122 @@ 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
@@ -837,6 +960,7 @@ 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);
--
2.7.4

Join cip-dev@lists.cip-project.org to automatically receive all group messages.