libqos/ahci: Add ahci_port_select helper

This helper identifies which port of the
AHCI HBA has a device we may run tests on.

Signed-off-by: John Snow <jsnow@redhat.com>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Message-id: 1423158090-25580-2-git-send-email-jsnow@redhat.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>

1 files changed, 27 insertions, 0 deletions

diff --git a/tests/libqos/ahci.c b/tests/libqos/ahci.c
index 5164d42450..7ea55f90b7 100644
--- a/tests/libqos/ahci.c
+++ b/tests/libqos/ahci.c
@@ -267,3 +267,30 @@ void ahci_hba_enable(AHCIQState *ahci)
      * In the future, a small test-case to inspect the Register D2H FIS
      * and clear the initial interrupts might be good. */
 }
+
+/**
+ * Pick the first implemented and running port
+ */
+unsigned ahci_port_select(AHCIQState *ahci)
+{
+    uint32_t ports, reg;
+    unsigned i;
+
+    ports = ahci_rreg(ahci, AHCI_PI);
+    for (i = 0; i < 32; ports >>= 1, ++i) {
+        if (ports == 0) {
+            i = 32;
+        }
+
+        if (!(ports & 0x01)) {
+            continue;
+        }
+
+        reg = ahci_px_rreg(ahci, i, AHCI_PX_CMD);
+        if (BITSET(reg, AHCI_PX_CMD_ST)) {
+            break;
+        }
+    }
+    g_assert(i < 32);
+    return i;
+}