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Diffstat (limited to 'package/kernel/mac80211/patches/006-add-basic-register-field-manipulation-macros.patch')
| -rw-r--r-- | package/kernel/mac80211/patches/006-add-basic-register-field-manipulation-macros.patch | 145 |
1 files changed, 0 insertions, 145 deletions
diff --git a/package/kernel/mac80211/patches/006-add-basic-register-field-manipulation-macros.patch b/package/kernel/mac80211/patches/006-add-basic-register-field-manipulation-macros.patch deleted file mode 100644 index a51edf8182..0000000000 --- a/package/kernel/mac80211/patches/006-add-basic-register-field-manipulation-macros.patch +++ /dev/null @@ -1,145 +0,0 @@ -From: Jakub Kicinski <jakub.kicinski@netronome.com> -Date: Wed, 31 Aug 2016 12:46:44 +0100 -Subject: [PATCH] add basic register-field manipulation macros - -Common approach to accessing register fields is to define -structures or sets of macros containing mask and shift pair. -Operations on the register are then performed as follows: - - field = (reg >> shift) & mask; - - reg &= ~(mask << shift); - reg |= (field & mask) << shift; - -Defining shift and mask separately is tedious. Ivo van Doorn -came up with an idea of computing them at compilation time -based on a single shifted mask (later refined by Felix) which -can be used like this: - - #define REG_FIELD 0x000ff000 - - field = FIELD_GET(REG_FIELD, reg); - - reg &= ~REG_FIELD; - reg |= FIELD_PREP(REG_FIELD, field); - -FIELD_{GET,PREP} macros take care of finding out what the -appropriate shift is based on compilation time ffs operation. - -GENMASK can be used to define registers (which is usually -less error-prone and easier to match with datasheets). - -This approach is the most convenient I've seen so to limit code -multiplication let's move the macros to a global header file. -Attempts to use static inlines instead of macros failed due -to false positive triggering of BUILD_BUG_ON()s, especially with -GCC < 6.0. - -Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com> -Reviewed-by: Dinan Gunawardena <dinan.gunawardena@netronome.com> ---- - create mode 100644 include/linux/bitfield.h - ---- /dev/null -+++ b/include/linux/bitfield.h -@@ -0,0 +1,100 @@ -+/* -+ * Copyright (C) 2014 Felix Fietkau <nbd@nbd.name> -+ * Copyright (C) 2004 - 2009 Ivo van Doorn <IvDoorn@gmail.com> -+ * -+ * This program is free software; you can redistribute it and/or modify -+ * it under the terms of the GNU General Public License version 2 -+ * as published by the Free Software Foundation -+ * -+ * This program is distributed in the hope that it will be useful, -+ * but WITHOUT ANY WARRANTY; without even the implied warranty of -+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the -+ * GNU General Public License for more details. -+ */ -+ -+#ifndef _LINUX_BITFIELD_H -+#define _LINUX_BITFIELD_H -+ -+#include <linux/bug.h> -+ -+#ifdef __CHECKER__ -+#define __BUILD_BUG_ON_NOT_POWER_OF_2(n) (0) -+#else -+#define __BUILD_BUG_ON_NOT_POWER_OF_2(n) \ -+ BUILD_BUG_ON(((n) & ((n) - 1)) != 0) -+#endif -+ -+/* -+ * Bitfield access macros -+ * -+ * FIELD_{GET,PREP} macros take as first parameter shifted mask -+ * from which they extract the base mask and shift amount. -+ * Mask must be a compilation time constant. -+ * -+ * Example: -+ * -+ * #define REG_FIELD_A GENMASK(6, 0) -+ * #define REG_FIELD_B BIT(7) -+ * #define REG_FIELD_C GENMASK(15, 8) -+ * #define REG_FIELD_D GENMASK(31, 16) -+ * -+ * Get: -+ * a = FIELD_GET(REG_FIELD_A, reg); -+ * b = FIELD_GET(REG_FIELD_B, reg); -+ * -+ * Set: -+ * reg = FIELD_PREP(REG_FIELD_A, 1) | -+ * FIELD_PREP(REG_FIELD_B, 0) | -+ * FIELD_PREP(REG_FIELD_C, c) | -+ * FIELD_PREP(REG_FIELD_D, 0x40); -+ * -+ * Modify: -+ * reg &= ~REG_FIELD_C; -+ * reg |= FIELD_PREP(REG_FIELD_C, c); -+ */ -+ -+#define __bf_shf(x) (__builtin_ffsll(x) - 1) -+ -+#define __BF_FIELD_CHECK(_mask, _reg, _val, _pfx) \ -+ ({ \ -+ BUILD_BUG_ON_MSG(!__builtin_constant_p(_mask), \ -+ _pfx "mask is not constant"); \ -+ BUILD_BUG_ON_MSG(!(_mask), _pfx "mask is zero"); \ -+ BUILD_BUG_ON_MSG(__builtin_constant_p(_val) ? \ -+ ~((_mask) >> __bf_shf(_mask)) & (_val) : 0, \ -+ _pfx "value too large for the field"); \ -+ BUILD_BUG_ON_MSG((_mask) > (typeof(_reg))~0ull, \ -+ _pfx "type of reg too small for mask"); \ -+ __BUILD_BUG_ON_NOT_POWER_OF_2((_mask) + \ -+ (1ULL << __bf_shf(_mask))); \ -+ }) -+ -+/** -+ * FIELD_PREP() - prepare a bitfield element -+ * @_mask: shifted mask defining the field's length and position -+ * @_val: value to put in the field -+ * -+ * FIELD_PREP() masks and shifts up the value. The result should -+ * be combined with other fields of the bitfield using logical OR. -+ */ -+#define FIELD_PREP(_mask, _val) \ -+ ({ \ -+ __BF_FIELD_CHECK(_mask, 0ULL, _val, "FIELD_PREP: "); \ -+ ((typeof(_mask))(_val) << __bf_shf(_mask)) & (_mask); \ -+ }) -+ -+/** -+ * FIELD_GET() - extract a bitfield element -+ * @_mask: shifted mask defining the field's length and position -+ * @_reg: 32bit value of entire bitfield -+ * -+ * FIELD_GET() extracts the field specified by @_mask from the -+ * bitfield passed in as @_reg by masking and shifting it down. -+ */ -+#define FIELD_GET(_mask, _reg) \ -+ ({ \ -+ __BF_FIELD_CHECK(_mask, _reg, 0U, "FIELD_GET: "); \ -+ (typeof(_mask))(((_reg) & (_mask)) >> __bf_shf(_mask)); \ -+ }) -+ -+#endif |