projects / deliverable / linux.git / blame
| Commit | Line | Data |
|---|---|---|
| 7366b92a TF |
1 | Interface for registering and calling firmware-specific operations for ARM. |
| 2 | ---- | |
| 3 | Written by Tomasz Figa <t.figa@samsung.com> | |
| 4 | ||
| 5 | Some boards are running with secure firmware running in TrustZone secure | |
| 6 | world, which changes the way some things have to be initialized. This makes | |
| 7 | a need to provide an interface for such platforms to specify available firmware | |
| 8 | operations and call them when needed. | |
| 9 | ||
| 10 | Firmware operations can be specified using struct firmware_ops | |
| 11 | ||
| 12 | struct firmware_ops { | |
| 13 | /* | |
| 14 | * Enters CPU idle mode | |
| 15 | */ | |
| 16 | int (*do_idle)(void); | |
| 17 | /* | |
| 18 | * Sets boot address of specified physical CPU | |
| 19 | */ | |
| 20 | int (*set_cpu_boot_addr)(int cpu, unsigned long boot_addr); | |
| 21 | /* | |
| 22 | * Boots specified physical CPU | |
| 23 | */ | |
| 24 | int (*cpu_boot)(int cpu); | |
| 25 | /* | |
| 26 | * Initializes L2 cache | |
| 27 | */ | |
| 28 | int (*l2x0_init)(void); | |
| 29 | }; | |
| 30 | ||
| 31 | and then registered with register_firmware_ops function | |
| 32 | ||
| 33 | void register_firmware_ops(const struct firmware_ops *ops) | |
| 34 | ||
| 35 | the ops pointer must be non-NULL. | |
| 36 | ||
| 37 | There is a default, empty set of operations provided, so there is no need to | |
| 38 | set anything if platform does not require firmware operations. | |
| 39 | ||
| 40 | To call a firmware operation, a helper macro is provided | |
| 41 | ||
| 42 | #define call_firmware_op(op, ...) \ | |
| 43 | ((firmware_ops->op) ? firmware_ops->op(__VA_ARGS__) : (-ENOSYS)) | |
| 44 | ||
| 45 | the macro checks if the operation is provided and calls it or otherwise returns | |
| 46 | -ENOSYS to signal that given operation is not available (for example, to allow | |
| 47 | fallback to legacy operation). | |
| 48 | ||
| 49 | Example of registering firmware operations: | |
| 50 | ||
| 51 | /* board file */ | |
| 52 | ||
| 53 | static int platformX_do_idle(void) | |
| 54 | { | |
| 55 | /* tell platformX firmware to enter idle */ | |
| 56 | return 0; | |
| 57 | } | |
| 58 | ||
| 59 | static int platformX_cpu_boot(int i) | |
| 60 | { | |
| 61 | /* tell platformX firmware to boot CPU i */ | |
| 62 | return 0; | |
| 63 | } | |
| 64 | ||
| 65 | static const struct firmware_ops platformX_firmware_ops = { | |
| 66 | .do_idle = exynos_do_idle, | |
| 67 | .cpu_boot = exynos_cpu_boot, | |
| 68 | /* other operations not available on platformX */ | |
| 69 | }; | |
| 70 | ||
| 71 | /* init_early callback of machine descriptor */ | |
| 72 | static void __init board_init_early(void) | |
| 73 | { | |
| 74 | register_firmware_ops(&platformX_firmware_ops); | |
| 75 | } | |
| 76 | ||
| 77 | Example of using a firmware operation: | |
| 78 | ||
| 79 | /* some platform code, e.g. SMP initialization */ | |
| 80 | ||
| 81 | __raw_writel(virt_to_phys(exynos4_secondary_startup), | |
| 82 | CPU1_BOOT_REG); | |
| 83 | ||
| 84 | /* Call Exynos specific smc call */ | |
| 85 | if (call_firmware_op(cpu_boot, cpu) == -ENOSYS) | |
| 86 | cpu_boot_legacy(...); /* Try legacy way */ | |
| 87 | ||
| 88 | gic_raise_softirq(cpumask_of(cpu), 1); |