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