These parameters are named differently from elsewhere in this file. Switch them to avoid confusion.
Also add comments to this function.
Signed-off-by: Simon Glass sjg@chromium.org Reviewed-by: Bin Meng bmeng.cn@gmail.com Reviewed-by: Wolfgang Wallner wolfgang.wallner@br-automation.com ---
(no changes since v2)
Changes in v2: - Add comments to explain what start_aps() does
arch/x86/cpu/mp_init.c | 25 +++++++++++++++++++------ 1 file changed, 19 insertions(+), 6 deletions(-)
diff --git a/arch/x86/cpu/mp_init.c b/arch/x86/cpu/mp_init.c index e77d7f2cd6..8b00d57c88 100644 --- a/arch/x86/cpu/mp_init.c +++ b/arch/x86/cpu/mp_init.c @@ -308,13 +308,26 @@ static int apic_wait_timeout(int total_delay, const char *msg) return 0; }
-static int start_aps(int ap_count, atomic_t *num_aps) +/** + * start_aps() - Start up the APs and count how many we find + * + * This is called on the boot processor to start up all the other processors + * (here called APs). + * + * @num_aps: Number of APs we expect to find + * @ap_count: Initially zero. Incremented by this function for each AP found + * @return 0 if all APs were set up correctly or there are none to set up, + * -ENOSPC if the SIPI vector is too high in memory, + * -ETIMEDOUT if the ICR is busy or the second SIPI fails to complete + * -EIO if not all APs check in correctly + */ +static int start_aps(int num_aps, atomic_t *ap_count) { int sipi_vector; /* Max location is 4KiB below 1MiB */ const int max_vector_loc = ((1 << 20) - (1 << 12)) >> 12;
- if (ap_count == 0) + if (num_aps == 0) return 0;
/* The vector is sent as a 4k aligned address in one byte */ @@ -326,7 +339,7 @@ static int start_aps(int ap_count, atomic_t *num_aps) return -ENOSPC; }
- debug("Attempting to start %d APs\n", ap_count); + debug("Attempting to start %d APs\n", num_aps);
if (apic_wait_timeout(1000, "ICR not to be busy")) return -ETIMEDOUT; @@ -349,7 +362,7 @@ static int start_aps(int ap_count, atomic_t *num_aps) return -ETIMEDOUT;
/* Wait for CPUs to check in up to 200 us */ - wait_for_aps(num_aps, ap_count, 200, 15); + wait_for_aps(ap_count, num_aps, 200, 15);
/* Send 2nd SIPI */ if (apic_wait_timeout(1000, "ICR not to be busy")) @@ -362,9 +375,9 @@ static int start_aps(int ap_count, atomic_t *num_aps) return -ETIMEDOUT;
/* Wait for CPUs to check in */ - if (wait_for_aps(num_aps, ap_count, 10000, 50)) { + if (wait_for_aps(ap_count, num_aps, 10000, 50)) { debug("Not all APs checked in: %d/%d\n", - atomic_read(num_aps), ap_count); + atomic_read(ap_count), num_aps); return -EIO; }