Hello Rasmus,
On 07.07.22 15:12, Rasmus Villemoes wrote:
The size of the dynamic stack allocation here is bounded by the if() statement. However, just allocating the maximum size up-front and doing malloc() if necessary avoids code duplication (the i2c_setup_offset() until the invocation of ->xfer), and generates much better (smaller) code:
bloat-o-meter drivers/i2c/i2c-uclass.o.{0,1} add/remove: 0/0 grow/shrink: 0/1 up/down: 0/-144 (-144) Function old new delta dm_i2c_write 552 408 -144 Total: Before=3828, After=3684, chg -3.76%
It also makes static analysis of maximum stack usage (using the .su files that are automatically generated during build) easier if there are no lines saying "dynamic".
[This is not entirely equivalent to the existing code; this now uses the stack for len <= 64 rather than len <= 63, but that seems like a more natural limit.]
Signed-off-by: Rasmus Villemoes rasmus.villemoes@prevas.dk
drivers/i2c/i2c-uclass.c | 30 ++++++++++++------------------ 1 file changed, 12 insertions(+), 18 deletions(-)
Applied to u-boot-i2c master
Thanks!
bye, Heiko