New helper to print named bits of some value (think flags fields).
Signed-off-by: Gerd Hoffmann kraxel@redhat.com --- include/drm/drm_print.h | 3 +++ drivers/gpu/drm/drm_print.c | 33 +++++++++++++++++++++++++++++++++ 2 files changed, 36 insertions(+)
diff --git a/include/drm/drm_print.h b/include/drm/drm_print.h index 112165d3195d..12d4916254b4 100644 --- a/include/drm/drm_print.h +++ b/include/drm/drm_print.h @@ -89,6 +89,9 @@ __printf(2, 3) void drm_printf(struct drm_printer *p, const char *f, ...); void drm_puts(struct drm_printer *p, const char *str); void drm_print_regset32(struct drm_printer *p, struct debugfs_regset32 *regset); +void drm_print_bits(struct drm_printer *p, + unsigned long value, const char *bits[], + unsigned int from, unsigned int to);
__printf(2, 0) /** diff --git a/drivers/gpu/drm/drm_print.c b/drivers/gpu/drm/drm_print.c index ad302d71eeee..dfa27367ebb8 100644 --- a/drivers/gpu/drm/drm_print.c +++ b/drivers/gpu/drm/drm_print.c @@ -185,6 +185,39 @@ void drm_printf(struct drm_printer *p, const char *f, ...) } EXPORT_SYMBOL(drm_printf);
+/** + * drm_print_bits - print bits to a &drm_printer stream + * + * Print bits (in flag fields for example) in human readable form. + * The first name in the @bits array is for the bit indexed by @from. + * + * @p: the &drm_printer + * @value: field value. + * @bits: Array with bit names. + * @from: start of bit range to print (inclusive). + * @to: end of bit range to print (exclusive). + */ +void drm_print_bits(struct drm_printer *p, + unsigned long value, const char *bits[], + unsigned int from, unsigned int to) +{ + bool first = true; + unsigned int i; + + for (i = from; i < to; i++) { + if (!(value & (1 << i))) + continue; + if (WARN_ON_ONCE(!bits[i-from])) + continue; + drm_printf(p, "%s%s", first ? "" : ",", + bits[i-from]); + first = false; + } + if (first) + drm_printf(p, "(none)"); +} +EXPORT_SYMBOL(drm_print_bits); + void drm_dev_printk(const struct device *dev, const char *level, const char *format, ...) {