1 ==========================================================================
2 Interface for registering and calling firmware-specific operations for ARM
3 ==========================================================================
4
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
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()
14 function::
15
16 void register_firmware_ops(const struct firmware_ops *ops)
17
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.
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
24 To 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
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
33 Example 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
61 Example 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);
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