* independent of board/firmware
  */
 
-static void *mailbox_0_set_regs[] = {
+static volatile void *mailbox_0_set_regs[] = {
        IOADDR(A_BCM1480_IMR_CPU0_BASE + R_BCM1480_IMR_MAILBOX_0_SET_CPU),
        IOADDR(A_BCM1480_IMR_CPU1_BASE + R_BCM1480_IMR_MAILBOX_0_SET_CPU),
        IOADDR(A_BCM1480_IMR_CPU2_BASE + R_BCM1480_IMR_MAILBOX_0_SET_CPU),
        IOADDR(A_BCM1480_IMR_CPU3_BASE + R_BCM1480_IMR_MAILBOX_0_SET_CPU),
 };
 
-static void *mailbox_0_clear_regs[] = {
+static volatile void *mailbox_0_clear_regs[] = {
        IOADDR(A_BCM1480_IMR_CPU0_BASE + R_BCM1480_IMR_MAILBOX_0_CLR_CPU),
        IOADDR(A_BCM1480_IMR_CPU1_BASE + R_BCM1480_IMR_MAILBOX_0_CLR_CPU),
        IOADDR(A_BCM1480_IMR_CPU2_BASE + R_BCM1480_IMR_MAILBOX_0_CLR_CPU),
        IOADDR(A_BCM1480_IMR_CPU3_BASE + R_BCM1480_IMR_MAILBOX_0_CLR_CPU),
 };
 
-static void *mailbox_0_regs[] = {
+static volatile void *mailbox_0_regs[] = {
        IOADDR(A_BCM1480_IMR_CPU0_BASE + R_BCM1480_IMR_MAILBOX_0_CPU),
        IOADDR(A_BCM1480_IMR_CPU1_BASE + R_BCM1480_IMR_MAILBOX_0_CPU),
        IOADDR(A_BCM1480_IMR_CPU2_BASE + R_BCM1480_IMR_MAILBOX_0_CPU),