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Tomasz Figa7366b922012-12-11 13:58:43 +09001Interface for registering and calling firmware-specific operations for ARM.
2----
3Written by Tomasz Figa <t.figa@samsung.com>
4
5Some boards are running with secure firmware running in TrustZone secure
6world, which changes the way some things have to be initialized. This makes
7a need to provide an interface for such platforms to specify available firmware
8operations and call them when needed.
9
10Firmware 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
31and then registered with register_firmware_ops function
32
33 void register_firmware_ops(const struct firmware_ops *ops)
34
35the ops pointer must be non-NULL.
36
37There is a default, empty set of operations provided, so there is no need to
38set anything if platform does not require firmware operations.
39
40To 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
45the 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
47fallback to legacy operation).
48
49Example 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
77Example 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);