Change in coreboot[master]: driver/intel/fsp2_0: Allow function to run serially on all APs

[Aamir Bohra (Code Review)]

Attention is currently required from: Furquan Shaikh, Paul Menzel, Tim Wawrzynczak, Angel Pons, Subrata Banik, Andrey Petrov, Patrick Rudolph.
Aamir Bohra has posted comments on this change. ( https://review.coreboot.org/c/coreboot/+/51085 )

Change subject: driver/intel/fsp2_0: Allow function to run serially on all APs
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Patch Set 2:

(5 comments)

Commit Message:

https://review.coreboot.org/c/coreboot/+/51085/comment/53e6a01a_d5a05bd4 
PS2, Line 9: singlethread
> The name seems to be `run_serial`.

Ack

https://review.coreboot.org/c/coreboot/+/51085/comment/d0dadc4f_394209c5 
PS2, Line 14:
> Please give some numbers, on how much time this actually saves. […]

Just adding a provision for serial run. Only for the were MP programming is recommended to run serially. Time would depend on the procedure to be run and also the timeout param in case it does not go through.

File src/drivers/intel/fsp2_0/ppi/mp_service_ppi.c:

https://review.coreboot.org/c/coreboot/+/51085/comment/c64cf287_c313c538 
PS2, Line 67: run_serial
> I’d prefer the opposite name `run_in_parallel`.

This is more to align with FSP EFI_PEI_MP_SERVICES_STARTUP_ALL_APS parameters.

https://review.coreboot.org/c/coreboot/+/51085/comment/4c91e32a_f247f5af 
PS2, Line 77: uint32_t
> get_cpu_count() returns an int

Ack

https://review.coreboot.org/c/coreboot/+/51085/comment/a858da71_eea7817c 
PS2, Line 91: MP_RUN_ON_ALL_CPUS
> I think this enum is named incorrectly. https://review.coreboot.org/cgit/coreboot. […]

ok to add a helper in mp init lib, you mean something like this?

diff --git a/src/cpu/x86/mp_init.c b/src/cpu/x86/mp_init.c
index cca6093458a..8788f650b6b 100644
--- a/src/cpu/x86/mp_init.c
+++ b/src/cpu/x86/mp_init.c
@@ -992,6 +992,19 @@ int mp_run_on_aps(void (*func)(void *), void *arg, int logical_cpu_num,
        return run_ap_work(&lcb, expire_us);
 }

+int mp_run_on_all_aps(void (*func)(void *), void *arg, long expire_us, bool run_serial)
+{
+       if (run_serial) {
+               for (int ap_index = 1; ap_index <= global_aps_num; ap_index++) {
+                       if (mp_run_on_aps(func, arg, ap_index, expire_us))
+                               printk(BIOS_ERR, "%s: failed running procedure on AP %d\n",
+                               __func__, ap_index);
+               }
+       } else {
+               return mp_run_on_aps(func, arg, 0, expire_us);
+       }
+}

and then call this from fsp driver?