1========================================================================== 2Interface for registering and calling firmware-specific operations for ARM 3========================================================================== 4 5Written by Tomasz Figa <t.figa@samsung.com> 6 7Some boards are running with secure firmware running in TrustZone secure 8world, which changes the way some things have to be initialized. This makes 9a need to provide an interface for such platforms to specify available firmware 10operations and call them when needed. 11 12Firmware operations can be specified by filling in a struct firmware_ops 13with appropriate callbacks and then registering it with register_firmware_ops() 14function:: 15 16 void register_firmware_ops(const struct firmware_ops *ops) 17 18The ops pointer must be non-NULL. More information about struct firmware_ops 19and its members can be found in arch/arm/include/asm/firmware.h header. 20 21There is a default, empty set of operations provided, so there is no need to 22set anything if platform does not require firmware operations. 23 24To call a firmware operation, a helper macro is provided:: 25 26 #define call_firmware_op(op, ...) \ 27 ((firmware_ops->op) ? firmware_ops->op(__VA_ARGS__) : (-ENOSYS)) 28 29the macro checks if the operation is provided and calls it or otherwise returns 30-ENOSYS to signal that given operation is not available (for example, to allow 31fallback to legacy operation). 32 33Example of registering firmware operations:: 34 35 /* board file */ 36 37 static int platformX_do_idle(void) 38 { 39 /* tell platformX firmware to enter idle */ 40 return 0; 41 } 42 43 static int platformX_cpu_boot(int i) 44 { 45 /* tell platformX firmware to boot CPU i */ 46 return 0; 47 } 48 49 static const struct firmware_ops platformX_firmware_ops = { 50 .do_idle = exynos_do_idle, 51 .cpu_boot = exynos_cpu_boot, 52 /* other operations not available on platformX */ 53 }; 54 55 /* init_early callback of machine descriptor */ 56 static void __init board_init_early(void) 57 { 58 register_firmware_ops(&platformX_firmware_ops); 59 } 60 61Example of using a firmware operation:: 62 63 /* some platform code, e.g. SMP initialization */ 64 65 __raw_writel(__pa_symbol(exynos4_secondary_startup), 66 CPU1_BOOT_REG); 67 68 /* Call Exynos specific smc call */ 69 if (call_firmware_op(cpu_boot, cpu) == -ENOSYS) 70 cpu_boot_legacy(...); /* Try legacy way */ 71 72 gic_raise_softirq(cpumask_of(cpu), 1); 73