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/*
* Copyright (C) 2019 Repk repk@triplefau.lt
*
* SPDX-License-Identifier: BSD-3-Clause
* https://spdx.org/licenses
*/
#include <inttypes.h>
#include <stdint.h>
#include <common/bl_common.h>
#include <common/debug.h>
#include <arch_helpers.h>
#include <plat/common/platform.h>
#include <bl31/ea_handle.h>
#define A53_SERR_INT_AXI_SLVERR_ON_EXTERNAL_ACCESS 0xbf000002
#if !ENABLE_BACKTRACE
static const char *get_el_str(unsigned int el)
{
if (el == MODE_EL3) {
return "EL3";
} else if (el == MODE_EL2) {
return "EL2";
}
return "S-EL1";
}
#endif /* !ENABLE_BACKTRACE */
/*
* This source file with custom plat_ea_handler function is compiled only when
* building TF-A with compile option HANDLE_EA_EL3_FIRST=1
*/
void plat_ea_handler(unsigned int ea_reason, uint64_t syndrome, void *cookie,
void *handle, uint64_t flags)
{
unsigned int level = (unsigned int)GET_EL(read_spsr_el3());
/*
* Asynchronous External Abort with syndrome 0xbf000002 on Cortex A53
* core means SError interrupt caused by AXI SLVERR on external access.
*
* In most cases this indicates a bug in U-Boot or Linux kernel driver
* pci-aardvark.c which implements access to A3700 PCIe config space.
* Driver does not wait for PCIe PIO transfer completion and try to
* start a new PCIe PIO transfer while previous has not finished yet.
* A3700 PCIe controller in this case sends SLVERR via AXI which results
* in a fatal Asynchronous SError interrupt on Cortex A53 CPU.
*
* Following patches fix that bug in U-Boot and Linux kernel drivers:
* https://source.denx.de/u-boot/u-boot/-/commit/eccbd4ad8e4e182638eafbfb87ac139c04f24a01
* https://git.kernel.org/stable/c/f18139966d072dab8e4398c95ce955a9742e04f7
*
* As a hacky workaround for unpatched U-Boot and Linux kernel drivers
* ignore all asynchronous aborts with that syndrome value received on
* CPU from level lower than EL3.
*
* Because these aborts are delivered on CPU asynchronously, they are
* imprecise and we cannot check the real reason of abort and neither
* who and why sent this abort. We expect that on A3700 it is always
* PCIe controller.
*
* Hence ignoring all aborts with this syndrome value is just a giant
* hack that we need only because of bugs in old U-Boot and Linux kernel
* versions and because it was decided that TF-A would implement this
* hack for U-Boot and Linux kernel it in this way. New patched U-Boot
* and kernel versions do not need it anymore.
*
* Links to discussion about this workaround:
* https://lore.kernel.org/linux-pci/20190316161243.29517-1-repk@triplefau.lt/
* https://lore.kernel.org/linux-pci/971be151d24312cc533989a64bd454b4@www.loen.fr/
* https://review.trustedfirmware.org/c/TF-A/trusted-firmware-a/+/1541
*/
if (level < MODE_EL3 && ea_reason == ERROR_EA_ASYNC &&
syndrome == A53_SERR_INT_AXI_SLVERR_ON_EXTERNAL_ACCESS) {
ERROR_NL();
ERROR("Ignoring Asynchronous External Abort with"
" syndrome 0x%" PRIx64 " received on 0x%lx from %s\n",
syndrome, read_mpidr_el1(), get_el_str(level));
ERROR("SError interrupt: AXI SLVERR on external access\n");
ERROR("This indicates a bug in pci-aardvark.c driver\n");
ERROR("Please update U-Boot/Linux to the latest version\n");
ERROR_NL();
console_flush();
return;
}
plat_default_ea_handler(ea_reason, syndrome, cookie, handle, flags);
}
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