[PATCH v5 4/7] drm/i915: Convert REG_GENMASK*() to fixed-width GENMASK_U*()

Vincent Mailhol via B4 Relay
2025-03-06T11:31:07Z

From: Lucas De Marchi <lucas.demarchi@intel.com>

Now that include/linux/bits.h implements fixed-width GENMASK_U*(), use
them to implement the i915/xe specific macros. Converting each driver
to use the generic macros are left for later, when/if other
driver-specific macros are also generalized.

Signed-off-by: Lucas De Marchi <lucas.demarchi@intel.com>
Acked-by: Jani Nikula <jani.nikula@intel.com>
Signed-off-by: Vincent Mailhol <mailhol.vincent@wanadoo.fr>
---
Changelog:

v4 -> v5:

- Add braket to macro names in patch description,
e.g. 'REG_GENMASK*' -> 'REG_GENMASK*()'

v3 -> v4:

- Remove the prefixes in macro parameters,
e.g. 'REG_GENMASK(__high, __low)' -> 'REG_GENMASK(high, low)'
---
drivers/gpu/drm/i915/i915_reg_defs.h | 108 ++++-------------------------------
1 file changed, 11 insertions(+), 97 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_reg_defs.h b/drivers/gpu/drm/i915/i915_reg_defs.h
index e251bcc0c89f5710125bc70f07851b2cb978c89c..39e5ed9511174b8757b9201bff735fa362651b34 100644
--- a/drivers/gpu/drm/i915/i915_reg_defs.h
+++ b/drivers/gpu/drm/i915/i915_reg_defs.h
@@ -9,76 +9,19 @@
#include <linux/bitfield.h>
#include <linux/bits.h>

-/**
- * REG_BIT() - Prepare a u32 bit value
- * @__n: 0-based bit number
- *
- * Local wrapper for BIT() to force u32, with compile time checks.
- *
- * @return: Value with bit @__n set.
- */
-#define REG_BIT(__n) \
- ((u32)(BIT(__n) + \
- BUILD_BUG_ON_ZERO(__is_constexpr(__n) && \
- ((__n) < 0 || (__n) > 31))))
-
-/**
- * REG_BIT8() - Prepare a u8 bit value
- * @__n: 0-based bit number
- *
- * Local wrapper for BIT() to force u8, with compile time checks.
- *
- * @return: Value with bit @__n set.
- */
-#define REG_BIT8(__n) \
- ((u8)(BIT(__n) + \
- BUILD_BUG_ON_ZERO(__is_constexpr(__n) && \
- ((__n) < 0 || (__n) > 7))))
-
-/**
- * REG_GENMASK() - Prepare a continuous u32 bitmask
- * @__high: 0-based high bit
- * @__low: 0-based low bit
- *
- * Local wrapper for GENMASK() to force u32, with compile time checks.
- *
- * @return: Continuous bitmask from @__high to @__low, inclusive.
- */
-#define REG_GENMASK(__high, __low) \
- ((u32)(GENMASK(__high, __low) + \
- BUILD_BUG_ON_ZERO(__is_constexpr(__high) && \
- __is_constexpr(__low) && \
- ((__low) < 0 || (__high) > 31 || (__low) > (__high)))))
-
-/**
- * REG_GENMASK64() - Prepare a continuous u64 bitmask
- * @__high: 0-based high bit
- * @__low: 0-based low bit
- *
- * Local wrapper for GENMASK_ULL() to force u64, with compile time checks.
- *
- * @return: Continuous bitmask from @__high to @__low, inclusive.
+/*
+ * Wrappers over the generic BIT_* and GENMASK_* implementations,
+ * for compatibility reasons with previous implementation
*/
-#define REG_GENMASK64(__high, __low) \
- ((u64)(GENMASK_ULL(__high, __low) + \
- BUILD_BUG_ON_ZERO(__is_constexpr(__high) && \
- __is_constexpr(__low) && \
- ((__low) < 0 || (__high) > 63 || (__low) > (__high)))))
+#define REG_GENMASK(high, low) GENMASK_U32(high, low)
+#define REG_GENMASK64(high, low) GENMASK_U64(high, low)
+#define REG_GENMASK16(high, low) GENMASK_U16(high, low)
+#define REG_GENMASK8(high, low) GENMASK_U8(high, low)

-/**
- * REG_GENMASK8() - Prepare a continuous u8 bitmask
- * @__high: 0-based high bit
- * @__low: 0-based low bit
- *
- * Local wrapper for GENMASK() to force u8, with compile time checks.
- *
- * @return: Continuous bitmask from @__high to @__low, inclusive.
- */
-#define REG_GENMASK8(__high, __low) \
- ((u8)(GENMASK(__high, __low) + \
- BUILD_BUG_ON_ZERO(__is_constexpr(__high) && \
- __is_constexpr(__low) && \
- ((__low) < 0 || (__high) > 7 || (__low) > (__high)))))
+#define REG_BIT(n) BIT_U32(n)
+#define REG_BIT64(n) BIT_U64(n)
+#define REG_BIT16(n) BIT_U16(n)
+#define REG_BIT8(n) BIT_U8(n)

/*
* Local integer constant expression version of is_power_of_2().
@@ -143,35 +86,6 @@
*/
#define REG_FIELD_GET64(__mask, __val) ((u64)FIELD_GET(__mask, __val))

-/**
- * REG_BIT16() - Prepare a u16 bit value
- * @__n: 0-based bit number
- *
- * Local wrapper for BIT() to force u16, with compile time
- * checks.
- *
- * @return: Value with bit @__n set.
- */
-#define REG_BIT16(__n) \
- ((u16)(BIT(__n) + \
- BUILD_BUG_ON_ZERO(__is_constexpr(__n) && \
- ((__n) < 0 || (__n) > 15))))
-
-/**
- * REG_GENMASK16() - Prepare a continuous u8 bitmask
- * @__high: 0-based high bit
- * @__low: 0-based low bit
- *
- * Local wrapper for GENMASK() to force u16, with compile time
- * checks.
- *
- * @return: Continuous bitmask from @__high to @__low, inclusive.
- */
-#define REG_GENMASK16(__high, __low) \
- ((u16)(GENMASK(__high, __low) + \
- BUILD_BUG_ON_ZERO(__is_constexpr(__high) && \
- __is_constexpr(__low) && \
- ((__low) < 0 || (__high) > 15 || (__low) > (__high)))))

/**
* REG_FIELD_PREP16() - Prepare a u16 bitfield value

--
2.45.3