| Message ID | cover.1552566113.git.vilhelm.gray@gmail.com (mailing list archive) |
|---|---|
| Headers | show |
| Series | Introduce the for_each_set_clump8 macro | expand |
On Thu, Mar 14, 2019 at 09:29:32PM +0900, William Breathitt Gray wrote: > Changes in v10: > - Fix off-by-one error in bitmap initialization in the > test_for_each_set_clump8 function > - Fix typos in clump_exp array definition in test_bitmap.c ("0x28" > should have been "0x38") > - Utilize for_each_set_clump8 macro in intel_soc_dts_iosf.c One more, can you look at gen_74x164_set_multiple() ? It seems a candidate as well, if I'm not mistaken.
On Fri, Mar 22, 2019 at 09:12:02PM +0200, Andy Shevchenko wrote: > On Thu, Mar 14, 2019 at 09:29:32PM +0900, William Breathitt Gray wrote: > > Changes in v10: > > - Fix off-by-one error in bitmap initialization in the > > test_for_each_set_clump8 function > > - Fix typos in clump_exp array definition in test_bitmap.c ("0x28" > > should have been "0x38") > > - Utilize for_each_set_clump8 macro in intel_soc_dts_iosf.c > > One more, can you look at gen_74x164_set_multiple() ? It seems a candidate as > well, if I'm not mistaken. We can utilize the for_each_set_clump8 macro in the gen_74x164_set_multiple function, but I skipped over it earlier since I noticed it used the BITS_PER_BYTE define rather than a hardcoded 8. If it always loops 8 bits at a time, then we can use the for_each_set_clump8 macro; otherwise we would need the more generic for_each_set_clump macro to handle the non-8-bit looping cases. Will BITS_PER_BYTE always be defined as 8 bits? William Breathitt Gray > > > -- > With Best Regards, > Andy Shevchenko > >
On Sun, Mar 24, 2019 at 5:07 AM William Breathitt Gray <vilhelm.gray@gmail.com> wrote: > On Fri, Mar 22, 2019 at 09:12:02PM +0200, Andy Shevchenko wrote: > > On Thu, Mar 14, 2019 at 09:29:32PM +0900, William Breathitt Gray wrote: > > > Changes in v10: > > > - Fix off-by-one error in bitmap initialization in the > > > test_for_each_set_clump8 function > > > - Fix typos in clump_exp array definition in test_bitmap.c ("0x28" > > > should have been "0x38") > > > - Utilize for_each_set_clump8 macro in intel_soc_dts_iosf.c > > > > One more, can you look at gen_74x164_set_multiple() ? It seems a candidate as > > well, if I'm not mistaken. > > We can utilize the for_each_set_clump8 macro in the > gen_74x164_set_multiple function, but I skipped over it earlier since I > noticed it used the BITS_PER_BYTE define rather than a hardcoded 8. If > it always loops 8 bits at a time, then we can use the > for_each_set_clump8 macro; otherwise we would need the more generic > for_each_set_clump macro to handle the non-8-bit looping cases. > > Will BITS_PER_BYTE always be defined as 8 bits? Yes, Linux cannot run on platforms where BITS_PER_BYTE != 8 (no 9-bit bytes ;) include/linux/bits.h:#define BITS_PER_BYTE 8 Gr{oetje,eeting}s, Geert
On Sun, Mar 24, 2019 at 6:12 AM William Breathitt Gray <vilhelm.gray@gmail.com> wrote: > > On Fri, Mar 22, 2019 at 09:12:02PM +0200, Andy Shevchenko wrote: > > On Thu, Mar 14, 2019 at 09:29:32PM +0900, William Breathitt Gray wrote: > > > Changes in v10: > > > - Fix off-by-one error in bitmap initialization in the > > > test_for_each_set_clump8 function > > > - Fix typos in clump_exp array definition in test_bitmap.c ("0x28" > > > should have been "0x38") > > > - Utilize for_each_set_clump8 macro in intel_soc_dts_iosf.c > > > > One more, can you look at gen_74x164_set_multiple() ? It seems a candidate as > > well, if I'm not mistaken. > > We can utilize the for_each_set_clump8 macro in the > gen_74x164_set_multiple function, but I skipped over it earlier since I > noticed it used the BITS_PER_BYTE define rather than a hardcoded 8. If > it always loops 8 bits at a time, then we can use the > for_each_set_clump8 macro; Yes, see below. > otherwise we would need the more generic > for_each_set_clump macro to handle the non-8-bit looping cases. > Will BITS_PER_BYTE always be defined as 8 bits? It's not correct question, the right one "is the hardware always in 8-bit chunks". And datasheet is crystal clear about this. This very old and famous IC has 8-bit from the 70-s (IIRC the epoch of the design). So, it is always in 8-bit chunks.
Changes in v10: - Fix off-by-one error in bitmap initialization in the test_for_each_set_clump8 function - Fix typos in clump_exp array definition in test_bitmap.c ("0x28" should have been "0x38") - Utilize for_each_set_clump8 macro in intel_soc_dts_iosf.c While adding GPIO get_multiple/set_multiple callback support for various drivers, I noticed a pattern of looping manifesting that would be useful standardized as a macro. This patchset introduces the for_each_set_clump8 macro and utilizes it in several GPIO drivers. The for_each_set_clump macro8 facilitates a for-loop syntax that iterates over a memory region entire groups of set bits at a time. For example, suppose you would like to iterate over a 32-bit integer 8 bits at a time, skipping over 8-bit groups with no set bit, where XXXXXXXX represents the current 8-bit group: Example: 10111110 00000000 11111111 00110011 First loop: 10111110 00000000 11111111 XXXXXXXX Second loop: 10111110 00000000 XXXXXXXX 00110011 Third loop: XXXXXXXX 00000000 11111111 00110011 Each iteration of the loop returns the next 8-bit group that has at least one set bit. The for_each_set_clump8 macro has four parameters: * start: set to the bit offset of the current clump * clump: set to the current clump value * bits: bitmap to search within * size: bitmap size in number of bits In this version of the patchset, the for_each_set_clump macro has been reimplemented and simplified based on the suggestions provided by Rasmus Villemoes and Andy Shevchenko in the version 4 submission. In particular, the function of the for_each_set_clump macro has been restricted to handle only 8-bit clumps; the drivers that use the for_each_set_clump macro only handle 8-bit ports so a generic for_each_set_clump implementation is not necessary. Thus, a solution for large clumps (i.e. those larger than the width of a bitmap word) can be postponed until a driver appears that actually requires such a generic for_each_set_clump implementation. For what it's worth, a semi-generic for_each_set_clump (i.e. for clumps smaller than the width of a bitmap word) can be implemented by simply replacing the hardcoded '8' and '0xFF' instances with respective variables. I have not yet had a need for such an implementation, and since it falls short of a true generic for_each_set_clump function, I have decided to forgo such an implementation for now. In addition, the bitmap_get_value8 and bitmap_set_value8 functions are introduced to get and set 8-bit values respectively. Their use is based on the behavior suggested in the patchset version 4 review. William Breathitt Gray (10): bitops: Introduce the for_each_set_clump8 macro lib/test_bitmap.c: Add for_each_set_clump8 test cases gpio: 104-dio-48e: Utilize for_each_set_clump8 macro gpio: 104-idi-48: Utilize for_each_set_clump8 macro gpio: gpio-mm: Utilize for_each_set_clump8 macro gpio: ws16c48: Utilize for_each_set_clump8 macro gpio: pci-idio-16: Utilize for_each_set_clump8 macro gpio: pcie-idio-24: Utilize for_each_set_clump8 macro gpio: uniphier: Utilize for_each_set_clump8 macro thermal: intel: intel_soc_dts_iosf: Utilize for_each_set_clump8 macro drivers/gpio/gpio-104-dio-48e.c | 73 ++++---------- drivers/gpio/gpio-104-idi-48.c | 37 ++----- drivers/gpio/gpio-gpio-mm.c | 73 ++++---------- drivers/gpio/gpio-pci-idio-16.c | 75 ++++++-------- drivers/gpio/gpio-pcie-idio-24.c | 111 ++++++++------------- drivers/gpio/gpio-uniphier.c | 16 ++- drivers/gpio/gpio-ws16c48.c | 72 ++++--------- drivers/thermal/intel/intel_soc_dts_iosf.c | 29 +++--- drivers/thermal/intel/intel_soc_dts_iosf.h | 2 - include/asm-generic/bitops/find.h | 14 +++ include/linux/bitops.h | 5 + lib/find_bit.c | 81 +++++++++++++++ lib/test_bitmap.c | 65 ++++++++++++ 13 files changed, 330 insertions(+), 323 deletions(-)