1 /* 2 * Copyright (C) 2019 Repk repk@triplefau.lt 3 * 4 * SPDX-License-Identifier: BSD-3-Clause 5 * https://spdx.org/licenses 6 */ 7 8 #include <inttypes.h> 9 #include <stdint.h> 10 11 #include <common/bl_common.h> 12 #include <common/debug.h> 13 #include <arch_helpers.h> 14 #include <plat/common/platform.h> 15 #include <bl31/ea_handle.h> 16 17 #define A53_SERR_INT_AXI_SLVERR_ON_EXTERNAL_ACCESS 0xbf000002 18 19 /* 20 * This source file with custom plat_ea_handler function is compiled only when 21 * building TF-A with compile option HANDLE_EA_EL3_FIRST_NS=1 22 */ 23 void plat_ea_handler(unsigned int ea_reason, uint64_t syndrome, void *cookie, 24 void *handle, uint64_t flags) 25 { 26 unsigned int level = (unsigned int)GET_EL(read_spsr_el3()); 27 28 /* 29 * Asynchronous External Abort with syndrome 0xbf000002 on Cortex A53 30 * core means SError interrupt caused by AXI SLVERR on external access. 31 * 32 * In most cases this indicates a bug in U-Boot or Linux kernel driver 33 * pci-aardvark.c which implements access to A3700 PCIe config space. 34 * Driver does not wait for PCIe PIO transfer completion and try to 35 * start a new PCIe PIO transfer while previous has not finished yet. 36 * A3700 PCIe controller in this case sends SLVERR via AXI which results 37 * in a fatal Asynchronous SError interrupt on Cortex A53 CPU. 38 * 39 * Following patches fix that bug in U-Boot and Linux kernel drivers: 40 * https://source.denx.de/u-boot/u-boot/-/commit/eccbd4ad8e4e182638eafbfb87ac139c04f24a01 41 * https://git.kernel.org/stable/c/f18139966d072dab8e4398c95ce955a9742e04f7 42 * 43 * As a hacky workaround for unpatched U-Boot and Linux kernel drivers 44 * ignore all asynchronous aborts with that syndrome value received on 45 * CPU from level lower than EL3. 46 * 47 * Because these aborts are delivered on CPU asynchronously, they are 48 * imprecise and we cannot check the real reason of abort and neither 49 * who and why sent this abort. We expect that on A3700 it is always 50 * PCIe controller. 51 * 52 * Hence ignoring all aborts with this syndrome value is just a giant 53 * hack that we need only because of bugs in old U-Boot and Linux kernel 54 * versions and because it was decided that TF-A would implement this 55 * hack for U-Boot and Linux kernel it in this way. New patched U-Boot 56 * and kernel versions do not need it anymore. 57 * 58 * Links to discussion about this workaround: 59 * https://lore.kernel.org/linux-pci/20190316161243.29517-1-repk@triplefau.lt/ 60 * https://lore.kernel.org/linux-pci/971be151d24312cc533989a64bd454b4@www.loen.fr/ 61 * https://review.trustedfirmware.org/c/TF-A/trusted-firmware-a/+/1541 62 */ 63 if (level < MODE_EL3 && ea_reason == ERROR_EA_ASYNC && 64 syndrome == A53_SERR_INT_AXI_SLVERR_ON_EXTERNAL_ACCESS) { 65 ERROR_NL(); 66 ERROR("Ignoring Asynchronous External Abort with" 67 " syndrome 0x%" PRIx64 " received on 0x%lx from %s\n", 68 syndrome, read_mpidr_el1(), get_el_str(level)); 69 ERROR("SError interrupt: AXI SLVERR on external access\n"); 70 ERROR("This indicates a bug in pci-aardvark.c driver\n"); 71 ERROR("Please update U-Boot/Linux to the latest version\n"); 72 ERROR_NL(); 73 console_flush(); 74 return; 75 } 76 77 plat_default_ea_handler(ea_reason, syndrome, cookie, handle, flags); 78 } 79