9c261f89a3
This patch extends the firmware_ops structure with two new callbacks: .suspend() and .resume(). The former is intended to ask the firmware to save all its volatile state and suspend the system, without returning back to the kernel in between. The latter is to be called early by very low level platform suspend code after waking up to restore low level hardware state, which can't be restored in non-secure mode. While at it, outdated version of the structure is removed from the documentation and replaced with a reference to the header file. Signed-off-by: Tomasz Figa <t.figa@samsung.com> Acked-by: Alexandre Courbot <acourbot@nvidia.com> Signed-off-by: Kukjin Kim <kgene.kim@samsung.com>
70 lines
2.2 KiB
Text
70 lines
2.2 KiB
Text
Interface for registering and calling firmware-specific operations for ARM.
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----
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Written by Tomasz Figa <t.figa@samsung.com>
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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(virt_to_phys(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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