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![Lukas Auer](/assets/img/avatar_default.png)
Harts on RISC-V boot independently, U-Boot is responsible for managing them. Functions are called on other harts with smp_call_function(), which sends inter-processor interrupts (IPIs) to all other available harts. Available harts are those marked as available in the device tree and present in the available_harts mask stored in global data. The available_harts mask is used to register all harts that have entered U-Boot. Functions are specified with their address and two function arguments (argument 2 and 3). The first function argument is always the hart ID of the hart calling the function. On the other harts, the IPI interrupt handler handle_ipi() must be called on software interrupts to handle the request and call the specified function. Functions are stored in the ipi_data data structure. Every hart has its own data structure in global data. While this is not required at the moment (all harts are expected to boot Linux), this does allow future expansion, where other harts may be used for monitoring or other tasks. Signed-off-by: Lukas Auer <lukas.auer@aisec.fraunhofer.de> Reviewed-by: Anup Patel <anup.patel@wdc.com> Reviewed-by: Bin Meng <bmeng.cn@gmail.com> Tested-by: Bin Meng <bmeng.cn@gmail.com>
54 lines
1.4 KiB
C
54 lines
1.4 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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/*
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* Copyright (C) 2019 Fraunhofer AISEC,
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* Lukas Auer <lukas.auer@aisec.fraunhofer.de>
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*/
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#ifndef _ASM_RISCV_SMP_H
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#define _ASM_RISCV_SMP_H
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/**
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* struct ipi_data - Inter-processor interrupt (IPI) data structure
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*
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* IPIs are used for SMP support to communicate to other harts what function to
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* call. Functions are in the form
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* void (*addr)(ulong hart, ulong arg0, ulong arg1).
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*
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* The function address and the two arguments, arg0 and arg1, are stored in the
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* IPI data structure. The hart ID is inserted by the hart handling the IPI and
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* calling the function.
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*
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* @addr: Address of function
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* @arg0: First argument of function
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* @arg1: Second argument of function
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*/
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struct ipi_data {
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ulong addr;
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ulong arg0;
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ulong arg1;
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};
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/**
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* handle_ipi() - interrupt handler for software interrupts
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*
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* The IPI interrupt handler must be called to handle software interrupts. It
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* calls the function specified in the hart's IPI data structure.
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*
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* @hart: Hart ID of the current hart
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*/
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void handle_ipi(ulong hart);
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/**
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* smp_call_function() - Call a function on all other harts
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*
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* Send IPIs with the specified function call to all harts.
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*
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* @addr: Address of function
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* @arg0: First argument of function
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* @arg1: Second argument of function
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* @return 0 if OK, -ve on error
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*/
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int smp_call_function(ulong addr, ulong arg0, ulong arg1);
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#endif
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