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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); |