drm: tweak drm_print_bits()

There is little reason for the from/to logic, printing a subset of
the bits can be done by simply shifting/masking value if needed.

Also use for_each_set_bit().

Suggested-by: Jani Nikula <jani.nikula@linux.intel.com>
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
Reviewed-by: Jani Nikula <jani.nikula@intel.com>
Acked-by: Sean Paul <sean@poorly.run>
Link: http://patchwork.freedesktop.org/patch/msgid/20190923065814.4797-1-kraxel@redhat.com

diff --git a/drivers/gpu/drm/drm_gem_ttm_helper.c b/drivers/gpu/drm/drm_gem_ttm_helper.c
index 9a4bafc..a534104 100644 (file)
--- a/drivers/gpu/drm/drm_gem_ttm_helper.c
+++ b/drivers/gpu/drm/drm_gem_ttm_helper.c
@@ -23,7 +23,7 @@
 void drm_gem_ttm_print_info(struct drm_printer *p, unsigned int indent,
                            const struct drm_gem_object *gem)
 {
-       static const char const *plname[] = {
+       static const char * const plname[] = {
                [ TTM_PL_SYSTEM ] = "system",
                [ TTM_PL_TT     ] = "tt",
                [ TTM_PL_VRAM   ] = "vram",
@@ -40,7 +40,7 @@ void drm_gem_ttm_print_info(struct drm_printer *p, unsigned int indent,
        const struct ttm_buffer_object *bo = drm_gem_ttm_of_gem(gem);
 
        drm_printf_indent(p, indent, "placement=");
-       drm_print_bits(p, bo->mem.placement, plname, 0, ARRAY_SIZE(plname));
+       drm_print_bits(p, bo->mem.placement, plname, ARRAY_SIZE(plname));
        drm_printf(p, "\n");
 
        if (bo->mem.bus.is_iomem) {

diff --git a/drivers/gpu/drm/drm_print.c b/drivers/gpu/drm/drm_print.c
index dfa2736..52cc7b3 100644 (file)
--- a/drivers/gpu/drm/drm_print.c
+++ b/drivers/gpu/drm/drm_print.c
@@ -189,28 +189,26 @@ 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).
+ * @nbits: Size of bit names array.
  */
-void drm_print_bits(struct drm_printer *p,
-                   unsigned long value, const char *bits[],
-                   unsigned int from, unsigned int to)
+void drm_print_bits(struct drm_printer *p, unsigned long value,
+                   const char * const bits[], unsigned int nbits)
 {
        bool first = true;
        unsigned int i;
 
-       for (i = from; i < to; i++) {
-               if (!(value & (1 << i)))
-                       continue;
-               if (WARN_ON_ONCE(!bits[i-from]))
+       if (WARN_ON_ONCE(nbits > BITS_PER_TYPE(value)))
+               nbits = BITS_PER_TYPE(value);
+
+       for_each_set_bit(i, &value, nbits) {
+               if (WARN_ON_ONCE(!bits[i]))
                        continue;
                drm_printf(p, "%s%s", first ? "" : ",",
-                          bits[i-from]);
+                          bits[i]);
                first = false;
        }
        if (first)

diff --git a/include/drm/drm_print.h b/include/drm/drm_print.h
index 12d4916..89d38d0 100644 (file)
--- a/include/drm/drm_print.h
+++ b/include/drm/drm_print.h
@@ -89,9 +89,8 @@ __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);
+void drm_print_bits(struct drm_printer *p, unsigned long value,
+                   const char * const bits[], unsigned int nbits);
 
 __printf(2, 0)
 /**