[PATCH] pinctrl: pinconf-generic: widen the packed config argument to unsigned long

[Peng Fan]

From: Peng Fan <peng.fan@xxxxxxx>

The packed pin configuration stores the parameter in the lower 8 bits and
the argument in the remaining bits of an unsigned long. However, the
argument was limited to 24 bits: pinconf_to_config_argument() masked it
with 0xffffff, and pinconf_to_config_packed() took a u32 argument, so even
on 64-bit systems the left shift in PIN_CONF_PACKED() discarded the upper
bits. For example, the pad configuration value 0x1080000 used by a new
i.MX SoC was packed as 0x08000000 and read back as 0x80000.

Allow the argument to use the full width of unsigned long so that such
values survive the pack/unpack round trip. Cast the argument in
PIN_CONF_PACKED() to unsigned long to keep direct users of the macro
consistent with pinconf_to_config_packed(), and print the full argument
in the debugfs dumps.

The packed argument only has BITS_PER_LONG - 8 bits available, so on
32-bit systems values above 0xffffff still cannot be represented. Reject
such firmware properties instead of silently truncating them.

Signed-off-by: Peng Fan <peng.fan@xxxxxxx>
---
 drivers/pinctrl/pinconf-generic.c       | 16 +++++++++++-----
 include/linux/pinctrl/pinconf-generic.h | 13 ++++++++-----
 2 files changed, 19 insertions(+), 10 deletions(-)

diff --git a/drivers/pinctrl/pinconf-generic.c b/drivers/pinctrl/pinconf-generic.c
index 36845517984e..0876015a6575 100644
--- a/drivers/pinctrl/pinconf-generic.c
+++ b/drivers/pinctrl/pinconf-generic.c
@@ -95,12 +95,12 @@ static void pinconf_generic_dump_one(struct pinctrl_dev *pctldev,
 		seq_puts(s, item->display);
 		/* Print unit if available */
 		if (item->has_arg) {
-			u32 val = pinconf_to_config_argument(config);
+			unsigned long val = pinconf_to_config_argument(config);
 
 			if (item->format)
-				seq_printf(s, " (%u %s)", val, item->format);
+				seq_printf(s, " (%lu %s)", val, item->format);
 			else
-				seq_printf(s, " (0x%x)", val);
+				seq_printf(s, " (0x%lx)", val);
 
 			if (item->values && item->num_values) {
 				if (val < item->num_values)
@@ -152,7 +152,7 @@ void pinconf_generic_dump_config(struct pinctrl_dev *pctldev,
 	for (i = 0; i < ARRAY_SIZE(conf_items); i++) {
 		if (pinconf_to_config_param(config) != conf_items[i].param)
 			continue;
-		seq_printf(s, "%s: 0x%x", conf_items[i].display,
+		seq_printf(s, "%s: 0x%lx", conf_items[i].display,
 			   pinconf_to_config_argument(config));
 	}
 
@@ -164,7 +164,7 @@ void pinconf_generic_dump_config(struct pinctrl_dev *pctldev,
 		if (pinconf_to_config_param(config) !=
 		    pctldev->desc->custom_conf_items[i].param)
 			continue;
-		seq_printf(s, "%s: 0x%x",
+		seq_printf(s, "%s: 0x%lx",
 				pctldev->desc->custom_conf_items[i].display,
 				pinconf_to_config_argument(config));
 	}
@@ -268,6 +268,12 @@ static int parse_fw_cfg(struct fwnode_handle *fwnode,
 			}
 		}
 
+		if (val & ~PIN_CONF_ARG_MASK) {
+			pr_err("%pfw: value %#x for %s does not fit in the pinconf argument\n",
+			       fwnode, val, par->property);
+			return -EINVAL;
+		}
+
 		pr_debug("found %s with value %u\n", par->property, val);
 		cfg[*ncfg] = pinconf_to_config_packed(par->param, val);
 		(*ncfg)++;
diff --git a/include/linux/pinctrl/pinconf-generic.h b/include/linux/pinctrl/pinconf-generic.h
index 1df63c732b99..9d28d4de1415 100644
--- a/include/linux/pinctrl/pinconf-generic.h
+++ b/include/linux/pinctrl/pinconf-generic.h
@@ -172,27 +172,30 @@ enum pin_config_param {
 /*
  * Helpful configuration macro to be used in tables etc.
  */
-#define PIN_CONF_PACKED(p, a) ((a << 8) | ((unsigned long) p & 0xffUL))
+#define PIN_CONF_PACKED(p, a) \
+	(((unsigned long) a << 8) | ((unsigned long) p & 0xffUL))
 
 /*
  * The following inlines stuffs a configuration parameter and data value
  * into and out of an unsigned long argument, as used by the generic pin config
  * system. We put the parameter in the lower 8 bits and the argument in the
- * upper 24 bits.
+ * upper BITS_PER_LONG - 8 bits.
  */
 
+#define PIN_CONF_ARG_MASK	(~0UL >> 8)
+
 static inline enum pin_config_param pinconf_to_config_param(unsigned long config)
 {
 	return (enum pin_config_param) (config & 0xffUL);
 }
 
-static inline u32 pinconf_to_config_argument(unsigned long config)
+static inline unsigned long pinconf_to_config_argument(unsigned long config)
 {
-	return (u32) ((config >> 8) & 0xffffffUL);
+	return (config >> 8) & PIN_CONF_ARG_MASK;
 }
 
 static inline unsigned long pinconf_to_config_packed(enum pin_config_param param,
-						     u32 argument)
+						     unsigned long argument)
 {
 	return PIN_CONF_PACKED(param, argument);
 }

---
base-commit: ddfe51b0a0f5dc9e415cc2c8ad8db17532dd426b
change-id: 20261109-pinconf-widen-07813693c2af

Best regards,
-- 
Peng Fan <peng.fan@xxxxxxx>