| Message ID | 20220810014024.27568-1-samuel@sholland.org (mailing list archive) |
|---|---|
| State | Awaiting Upstream, archived |
| Headers | show |
| Series | clk: sunxi-ng: mp: Avoid computing the rate twice | expand |
Dne sreda, 10. avgust 2022 ob 03:40:24 CEST je Samuel Holland napisal(a): > ccu_mp_find_best() already computes a best_rate at the same time as the > best m and p factors. Return it so the caller does not need to duplicate > the division. > > Signed-off-by: Samuel Holland <samuel@sholland.org> Reviewed-by: Jernej Skrabec <jernej.skrabec@gmail.com> Other ccu_*_find_best() functions would also benefit with similar change. Best regards, Jernej
Quoting Samuel Holland (2022-08-09 18:40:24) > ccu_mp_find_best() already computes a best_rate at the same time as the > best m and p factors. Return it so the caller does not need to duplicate > the division. Did the compiler figure this out and thus this patch makes no difference to the final object code?
Hi Stephen, On 8/15/22 12:26, Stephen Boyd wrote: > Quoting Samuel Holland (2022-08-09 18:40:24) >> ccu_mp_find_best() already computes a best_rate at the same time as the >> best m and p factors. Return it so the caller does not need to duplicate >> the division. > > Did the compiler figure this out and thus this patch makes no difference > to the final object code? It makes a difference at least on my gcc version 11.1.0. Before: text data bss dec hex filename 18257 12 0 18269 475d drivers/clk/sunxi-ng/sunxi-ccu.o After: text data bss dec hex filename 18083 12 0 18095 46af drivers/clk/sunxi-ng/sunxi-ccu.o I will send a v2 covering all of the CCU clock types. Regards, Samuel
diff --git a/drivers/clk/sunxi-ng/ccu_mp.c b/drivers/clk/sunxi-ng/ccu_mp.c index 57cf2d615148..cc94a694cb67 100644 --- a/drivers/clk/sunxi-ng/ccu_mp.c +++ b/drivers/clk/sunxi-ng/ccu_mp.c @@ -10,9 +10,9 @@ #include "ccu_gate.h" #include "ccu_mp.h" -static void ccu_mp_find_best(unsigned long parent, unsigned long rate, - unsigned int max_m, unsigned int max_p, - unsigned int *m, unsigned int *p) +static unsigned long ccu_mp_find_best(unsigned long parent, unsigned long rate, + unsigned int max_m, unsigned int max_p, + unsigned int *m, unsigned int *p) { unsigned long best_rate = 0; unsigned int best_m = 0, best_p = 0; @@ -35,6 +35,8 @@ static void ccu_mp_find_best(unsigned long parent, unsigned long rate, *m = best_m; *p = best_p; + + return best_rate; } static unsigned long ccu_mp_find_best_with_parent_adj(struct clk_hw *hw, @@ -109,8 +111,7 @@ static unsigned long ccu_mp_round_rate(struct ccu_mux_internal *mux, max_p = cmp->p.max ?: 1 << ((1 << cmp->p.width) - 1); if (!clk_hw_can_set_rate_parent(&cmp->common.hw)) { - ccu_mp_find_best(*parent_rate, rate, max_m, max_p, &m, &p); - rate = *parent_rate / p / m; + rate = ccu_mp_find_best(*parent_rate, rate, max_m, max_p, &m, &p); } else { rate = ccu_mp_find_best_with_parent_adj(hw, parent_rate, rate, max_m, max_p);
ccu_mp_find_best() already computes a best_rate at the same time as the best m and p factors. Return it so the caller does not need to duplicate the division. Signed-off-by: Samuel Holland <samuel@sholland.org> --- drivers/clk/sunxi-ng/ccu_mp.c | 11 ++++++----- 1 file changed, 6 insertions(+), 5 deletions(-)