x86: mp_init: Switch parameter names in start_aps()

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>

diff --git a/arch/x86/cpu/mp_init.c b/arch/x86/cpu/mp_init.c
index e77d7f2cd6c327bb151ebcd5c9549414668bfb53..8b00d57c880b216c3c34623a7b6a464b9ce90423 100644 (file)
--- 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;
        }