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1 | ========================================================================== |
2 | Interface for registering and calling firmware-specific operations for ARM | |
3 | ========================================================================== | |
4 | ||
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5 | Written by Tomasz Figa <t.figa@samsung.com> |
6 | ||
7 | Some boards are running with secure firmware running in TrustZone secure | |
8 | world, which changes the way some things have to be initialized. This makes | |
9 | a need to provide an interface for such platforms to specify available firmware | |
10 | operations and call them when needed. | |
11 | ||
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12 | Firmware operations can be specified by filling in a struct firmware_ops |
13 | with appropriate callbacks and then registering it with register_firmware_ops() | |
dc7a12bd | 14 | function:: |
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15 | |
16 | void register_firmware_ops(const struct firmware_ops *ops) | |
17 | ||
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18 | The ops pointer must be non-NULL. More information about struct firmware_ops |
19 | and its members can be found in arch/arm/include/asm/firmware.h header. | |
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20 | |
21 | There is a default, empty set of operations provided, so there is no need to | |
22 | set anything if platform does not require firmware operations. | |
23 | ||
dc7a12bd | 24 | To call a firmware operation, a helper macro is provided:: |
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25 | |
26 | #define call_firmware_op(op, ...) \ | |
27 | ((firmware_ops->op) ? firmware_ops->op(__VA_ARGS__) : (-ENOSYS)) | |
28 | ||
29 | the 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 | |
31 | fallback to legacy operation). | |
32 | ||
dc7a12bd | 33 | Example of registering firmware operations:: |
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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 | ||
dc7a12bd | 61 | Example of using a firmware operation:: |
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62 | |
63 | /* some platform code, e.g. SMP initialization */ | |
64 | ||
7673f5b1 | 65 | __raw_writel(__pa_symbol(exynos4_secondary_startup), |
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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); |