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72 lines
2.3 KiB
72 lines
2.3 KiB
========================================================================== |
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Interface for registering and calling firmware-specific operations for ARM |
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========================================================================== |
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Written by Tomasz Figa <[email protected]> |
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Some boards are running with secure firmware running in TrustZone secure |
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world, which changes the way some things have to be initialized. This makes |
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a need to provide an interface for such platforms to specify available firmware |
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operations and call them when needed. |
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Firmware operations can be specified by filling in a struct firmware_ops |
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with appropriate callbacks and then registering it with register_firmware_ops() |
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function:: |
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void register_firmware_ops(const struct firmware_ops *ops) |
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The ops pointer must be non-NULL. More information about struct firmware_ops |
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and its members can be found in arch/arm/include/asm/firmware.h header. |
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There is a default, empty set of operations provided, so there is no need to |
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set anything if platform does not require firmware operations. |
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To call a firmware operation, a helper macro is provided:: |
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#define call_firmware_op(op, ...) \ |
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((firmware_ops->op) ? firmware_ops->op(__VA_ARGS__) : (-ENOSYS)) |
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the macro checks if the operation is provided and calls it or otherwise returns |
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-ENOSYS to signal that given operation is not available (for example, to allow |
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fallback to legacy operation). |
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Example of registering firmware operations:: |
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/* board file */ |
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static int platformX_do_idle(void) |
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{ |
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/* tell platformX firmware to enter idle */ |
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return 0; |
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} |
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static int platformX_cpu_boot(int i) |
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{ |
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/* tell platformX firmware to boot CPU i */ |
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return 0; |
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} |
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static const struct firmware_ops platformX_firmware_ops = { |
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.do_idle = exynos_do_idle, |
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.cpu_boot = exynos_cpu_boot, |
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/* other operations not available on platformX */ |
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}; |
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/* init_early callback of machine descriptor */ |
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static void __init board_init_early(void) |
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{ |
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register_firmware_ops(&platformX_firmware_ops); |
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} |
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Example of using a firmware operation:: |
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/* some platform code, e.g. SMP initialization */ |
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__raw_writel(__pa_symbol(exynos4_secondary_startup), |
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CPU1_BOOT_REG); |
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/* Call Exynos specific smc call */ |
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if (call_firmware_op(cpu_boot, cpu) == -ENOSYS) |
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cpu_boot_legacy(...); /* Try legacy way */ |
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gic_raise_softirq(cpumask_of(cpu), 1);
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