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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);