projects / linux-block.git / blame
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|---|---|---|
| dc7a12bd MCC |
1 | ========================================================================== |
| 2 | Interface for registering and calling firmware-specific operations for ARM | |
| 3 | ========================================================================== | |
| 4 | ||
| 7366b92a TF |
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 | ||
| 9c261f89 TF |
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:: |
| 7366b92a TF |
15 | |
| 16 | void register_firmware_ops(const struct firmware_ops *ops) | |
| 17 | ||
| 9c261f89 TF |
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. | |
| 7366b92a TF |
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:: |
| 7366b92a TF |
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:: |
| 7366b92a TF |
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:: |
| 7366b92a TF |
62 | |
| 63 | /* some platform code, e.g. SMP initialization */ | |
| 64 | ||
| 7673f5b1 | 65 | __raw_writel(__pa_symbol(exynos4_secondary_startup), |
| 7366b92a TF |
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); |