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+Interface for registering and calling firmware-specific operations for ARM.
+----
+Written by Tomasz Figa <t.figa@samsung.com>
+
+Some boards are running with secure firmware running in TrustZone secure
+world, which changes the way some things have to be initialized. This makes
+a need to provide an interface for such platforms to specify available firmware
+operations and call them when needed.
+
+Firmware operations can be specified using struct firmware_ops
+
+        struct firmware_ops {
+                /*
+                * Enters CPU idle mode
+                */
+                int (*do_idle)(void);
+                /*
+                * Sets boot address of specified physical CPU
+                */
+                int (*set_cpu_boot_addr)(int cpu, unsigned long boot_addr);
+                /*
+                * Boots specified physical CPU
+                */
+                int (*cpu_boot)(int cpu);
+                /*
+                * Initializes L2 cache
+                */
+                int (*l2x0_init)(void);
+        };
+
+and then registered with register_firmware_ops function
+
+        void register_firmware_ops(const struct firmware_ops *ops)
+
+the ops pointer must be non-NULL.
+
+There is a default, empty set of operations provided, so there is no need to
+set anything if platform does not require firmware operations.
+
+To call a firmware operation, a helper macro is provided
+
+        #define call_firmware_op(op, ...)                               \
+                ((firmware_ops->op) ? firmware_ops->op(__VA_ARGS__) : (-ENOSYS))
+
+the macro checks if the operation is provided and calls it or otherwise returns
+-ENOSYS to signal that given operation is not available (for example, to allow
+fallback to legacy operation).
+
+Example of registering firmware operations:
+
+        /* board file */
+
+        static int platformX_do_idle(void)
+        {
+                /* tell platformX firmware to enter idle */
+                return 0;
+        }
+
+        static int platformX_cpu_boot(int i)
+        {
+                /* tell platformX firmware to boot CPU i */
+                return 0;
+        }
+
+        static const struct firmware_ops platformX_firmware_ops = {
+                .do_idle        = exynos_do_idle,
+                .cpu_boot       = exynos_cpu_boot,
+                /* other operations not available on platformX */
+        };
+
+        /* init_early callback of machine descriptor */
+        static void __init board_init_early(void)
+        {
+                register_firmware_ops(&platformX_firmware_ops);
+        }
+
+Example of using a firmware operation:
+
+        /* some platform code, e.g. SMP initialization */
+
+        __raw_writel(virt_to_phys(exynos4_secondary_startup),
+                CPU1_BOOT_REG);
+
+        /* Call Exynos specific smc call */
+        if (call_firmware_op(cpu_boot, cpu) == -ENOSYS)
+                cpu_boot_legacy(...); /* Try legacy way */
+
+        gic_raise_softirq(cpumask_of(cpu), 1);