| Message ID | cover.1613134924.git.syednwaris@gmail.com (mailing list archive) |
|---|---|
| Headers | show |
| Series | Introduce the for_each_set_clump macro | expand |
On Fri, Feb 12, 2021 at 2:19 PM Syed Nayyar Waris <syednwaris@gmail.com> wrote: > > Hello Bartosz, > > Since this patchset primarily affects GPIO drivers, would you like > to pick it up through your GPIO tree? > Sure, as soon as you figure out what's wrong with the xilinx patch. Could you also follow William's suggestion and rename the functions? Bart
On Wed, Mar 3, 2021 at 8:13 PM Bartosz Golaszewski <bgolaszewski@baylibre.com> wrote: > > On Fri, Feb 12, 2021 at 2:19 PM Syed Nayyar Waris <syednwaris@gmail.com> wrote: > > > > Hello Bartosz, > > > > Since this patchset primarily affects GPIO drivers, would you like > > to pick it up through your GPIO tree? > > > > Sure, as soon as you figure out what's wrong with the xilinx patch. > Could you also follow William's suggestion and rename the functions? > > Bart I have incorporated William's suggestions and have also solved the build error coming in the xilinx patch. I am sharing the v3 patchset. Thanks ! Regards Syed Nayyar Waris
Hello Bartosz, Since this patchset primarily affects GPIO drivers, would you like to pick it up through your GPIO tree? This patchset introduces a new generic version of for_each_set_clump. The previous version of for_each_set_clump8 used a fixed size 8-bit clump, but the new generic version can work with clump of any size but less than or equal to BITS_PER_LONG. The patchset utilizes the new macro in several GPIO drivers. The earlier 8-bit for_each_set_clump8 facilitated 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. But with the new for_each_set_clump the clump size can be different from 8 bits. Moreover, the clump can be split at word boundary in situations where word size is not multiple of clump size. Following are examples showing the working of new macro for clump sizes of 24 bits and 6 bits. Example 1: clump size: 24 bits, Number of clumps (or ports): 10 bitmap stores the bit information from where successive clumps are retrieved. /* bitmap memory region */ 0x00aa0000ff000000; /* Most significant bits */ 0xaaaaaa0000ff0000; 0x000000aa000000aa; 0xbbbbabcdeffedcba; /* Least significant bits */ Different iterations of for_each_set_clump:- 'offset' is the bit position and 'clump' is the 24 bit clump from the above bitmap. Iteration first: offset: 0 clump: 0xfedcba Iteration second: offset: 24 clump: 0xabcdef Iteration third: offset: 48 clump: 0xaabbbb Iteration fourth: offset: 96 clump: 0xaa Iteration fifth: offset: 144 clump: 0xff Iteration sixth: offset: 168 clump: 0xaaaaaa Iteration seventh: offset: 216 clump: 0xff Loop breaks because in the end the remaining bits (0x00aa) size was less than clump size of 24 bits. In above example it can be seen that in iteration third, the 24 bit clump that was retrieved was split between bitmap[0] and bitmap[1]. This example also shows that 24 bit zeroes if present in between, were skipped (preserving the previous for_each_set_macro8 behaviour). Example 2: clump size = 6 bits, Number of clumps (or ports) = 3. /* bitmap memory region */ 0x00aa0000ff000000; /* Most significant bits */ 0xaaaaaa0000ff0000; 0x0f00000000000000; 0x0000000000000ac0; /* Least significant bits */ Different iterations of for_each_set_clump: 'offset' is the bit position and 'clump' is the 6 bit clump from the above bitmap. Iteration first: offset: 6 clump: 0x2b Loop breaks because 6 * 3 = 18 bits traversed in bitmap. Here 6 * 3 is clump size * no. of clumps. Changes in v2: - [Patch 1/3]: Shift the macros and related functions to gpiolib inside gpio/. Reduce the visibilty of 'for_each_set_clump' to gpio. - [Patch 1/3]: Remove __builtin_unreachable and simply use return statement. - Remove tests from lib/test_bitmap.c as 'for_each_set_clump' is now localised inside gpio/ only. Syed Nayyar Waris (3): gpiolib: : Introduce the for_each_set_clump macro gpio: thunderx: Utilize for_each_set_clump macro gpio: xilinx: Utilize generic bitmap_get_value and _set_value drivers/gpio/gpio-thunderx.c | 13 ++++-- drivers/gpio/gpio-xilinx.c | 63 ++++++++++++------------- drivers/gpio/gpiolib.c | 90 ++++++++++++++++++++++++++++++++++++ drivers/gpio/gpiolib.h | 28 +++++++++++ 4 files changed, 158 insertions(+), 36 deletions(-) base-commit: e71ba9452f0b5b2e8dc8aa5445198cd9214a6a62