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https://github.com/brain-hackers/u-boot-brain
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![Sean Anderson](/assets/img/avatar_default.png)
Some IPIs may already be pending when U-Boot is started. This could be a problem if a secondary hart tries to handle an IPI before the boot hart has initialized the IPI device. To be specific, the Kendryte K210 ROM-based bootloader does not clear IPIs before passing control to U-Boot. Without this patch, the secondary hart jumps to address 0x0 as soon as it enters secondary_hart_loop, and then hangs in its trap handler. This commit introduces a valid bit so secondary harts know when and IPI originates from U-Boot, and it is safe to use the IPI API. The valid bit is initialized to 0 by board_init_f_init_reserve. Before this, secondary harts wait in wait_for_gd_init. Signed-off-by: Sean Anderson <seanga2@gmail.com> Reviewed-by: Bin Meng <bin.meng@windriver.com> Reviewed-by: Rick Chen <rick@andestech.com> Reviewed-by: Leo Liang <ycliang@andestech.com>
105 lines
2.9 KiB
C
105 lines
2.9 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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* @valid is used to determine whether a sent IPI originated from U-Boot. It is
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* initialized to zero by board_init_f_alloc_reserve. When U-Boot sends its
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* first IPI, it is set to 1. This prevents already-pending IPIs not sent by
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* U-Boot from being taken.
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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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* @valid: Whether this IPI is valid
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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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unsigned int valid;
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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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* @wait: Wait for harts to acknowledge request
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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, int wait);
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/**
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* riscv_init_ipi() - Initialize inter-process interrupt (IPI) driver
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*
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* Platform code must provide this function. This function is called once after
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* the cpu driver is initialized. No other riscv_*_ipi() calls will be made
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* before this function is called.
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*
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* @return 0 if OK, -ve on error
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*/
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int riscv_init_ipi(void);
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/**
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* riscv_send_ipi() - Send inter-processor interrupt (IPI)
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*
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* Platform code must provide this function.
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*
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* @hart: Hart ID of receiving hart
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* @return 0 if OK, -ve on error
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*/
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int riscv_send_ipi(int hart);
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/**
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* riscv_clear_ipi() - Clear inter-processor interrupt (IPI)
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*
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* Platform code must provide this function.
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*
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* @hart: Hart ID of hart to be cleared
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* @return 0 if OK, -ve on error
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*/
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int riscv_clear_ipi(int hart);
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/**
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* riscv_get_ipi() - Get status of inter-processor interrupt (IPI)
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*
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* Platform code must provide this function.
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*
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* @hart: Hart ID of hart to be checked
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* @pending: Pointer to variable with result of the check,
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* 1 if IPI is pending, 0 otherwise
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* @return 0 if OK, -ve on error
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*/
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int riscv_get_ipi(int hart, int *pending);
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#endif
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