1 files changed, 135 insertions, 0 deletions
diff --git a/big-little/lib/ipi.c b/big-little/lib/ipi.c
new file mode 100755
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+++ b/big-little/lib/ipi.c
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+/*
+ * Copyright (c) 2012, ARM Limited. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with
+ * or without modification, are permitted provided that the
+ * following conditions are met:
+ *
+ * Redistributions of source code must retain the above
+ * copyright notice, this list of conditions and the
+ * following disclaimer.
+ *
+ * Redistributions in binary form must reproduce the
+ * above copyright notice, this list of conditions and
+ * the following disclaimer in the documentation
+ * and/or other materials provided with the distribution.
+ *
+ * Neither the name of ARM nor the names of its
+ * contributors may be used to endorse or promote products
+ * derived from this software without specific prior written
+ * permission.
+ */
+
+#include "ipi.h"
+#include "misc.h"
+#include "virt_helpers.h"
+#include "bakery.h"
+#include "hyp_vmmap.h"
+#include "gic_registers.h"
+
+extern void gic_send_ipi(unsigned, unsigned);
+
+/*
+ * Set of flags used by the interrupt handling code
+ * to distinguish between IPIs sent by the big-little
+ * code and the payload software.
+ * TODO: Assumes only one cpu will send an IPI at a
+ * time rather than multiple cpus sending the same
+ * IPI to each other at the same time from within the
+ * HYP mode.
+ */
+static unsigned lock_ipi_check;
+static unsigned hyp_ipi_check[16];
+
+/*
+ * Returns the id of the first IPI that is not pending on
+ * our cpu interface or the first IPI that is pending but
+ * was not generated by us. Returns 16 if no such IPI is
+ * found
+ */
+static unsigned get_free_ipi(void)
+{
+        unsigned shift, cpu_if_bit, cpu_id = read_cpuid(), cluster_id =
+                read_clusterid();
+        int ctr;
+
+        cpu_if_bit = 1 << get_cpuif(cluster_id, cpu_id);
+
+        /* Find the register offset */
+        for (ctr = 3; ctr >= 0; ctr--)
+                /* Check whether IPI<shift> has already been generated by us */
+                for (shift = 0; shift < 4; shift++) {
+                        if (read32
+                            (GIC_ID_PHY_BASE + GICD_SPENDSGIR +
+                             (ctr << 2)) & (cpu_if_bit << (shift << 3)))
+                                continue;
+
+                        return (ctr << 2) + shift;
+                }
+
+        return MAX_IPI;
+}
+
+/*
+ * Given a mask of destination cpus and what the IPI is supposed
+ * todo, select an unused IPI and send it.
+ */
+unsigned send_hyp_ipi(unsigned cpuif_mask, unsigned type)
+{
+        unsigned rc = TRUE;
+        unsigned ipi_no = 0;
+
+        /*
+         * First choose a non-pending IPI to avoid a clash with the OS.
+         */
+        ipi_no = get_free_ipi();
+        if (ipi_no == MAX_IPI) {
+                rc = FALSE;
+                return rc;
+        }
+
+        /*
+         * For this IPI set the mask in our global variable. We do it, payload software
+         * does not. But, first check whether any earlier IPIs have already been acked
+         */
+        while (TRUE) {
+                spin_lock(&lock_ipi_check);
+                if (hyp_ipi_check[ipi_no] & 0xff) {
+                        spin_unlock(&lock_ipi_check);
+                } else {
+                        hyp_ipi_check[ipi_no] = (type << 8) | cpuif_mask;
+                        dsb();
+                        spin_unlock(&lock_ipi_check);
+                        break;
+                }
+        };
+
+        /* Send the IPI to the cpu_mask */
+        gic_send_ipi(cpuif_mask, ipi_no);
+
+        return rc;
+}
+
+/*
+ * Given a received IPI, check whether it is a HYP IPI and return
+ * the type if so else 0
+ */
+unsigned get_hyp_ipi(unsigned cpu_if, unsigned ipi_no)
+{
+        unsigned type = 0;
+
+        spin_lock(&lock_ipi_check);
+        /*
+         * If this IPI was sent by the big-little code then our cpu_if bit must have
+         * been set in the ipi_check flag. Reset the bit and indicate that its an
+         * internal IPI.
+         */
+        if (hyp_ipi_check[ipi_no] & (1 << cpu_if)) {
+                type = hyp_ipi_check[ipi_no] >> 8;
+                hyp_ipi_check[ipi_no] &= ~(1 << cpu_if);
+                dsb();
+        }
+        spin_unlock(&lock_ipi_check);
+
+        return type;
+}