1 /* 2 * Copyright (C) 2019 Repk repk@triplefau.lt 3 * 4 * SPDX-License-Identifier: BSD-3-Clause 5 * https://spdx.org/licenses 6 */ 7 #include <common/bl_common.h> 8 #include <common/debug.h> 9 #include <arch_helpers.h> 10 #include <plat/common/platform.h> 11 #include <bl31/ea_handle.h> 12 13 #define A53_SERR_INT_AXI_SLVERR_ON_EXTERNAL_ACCESS 0xbf000002 14 15 #if !ENABLE_BACKTRACE 16 static const char *get_el_str(unsigned int el) 17 { 18 if (el == MODE_EL3) { 19 return "EL3"; 20 } else if (el == MODE_EL2) { 21 return "EL2"; 22 } 23 return "S-EL1"; 24 } 25 #endif /* !ENABLE_BACKTRACE */ 26 27 /* 28 * This source file with custom plat_ea_handler function is compiled only when 29 * building TF-A with compile option HANDLE_EA_EL3_FIRST=1 30 */ 31 void plat_ea_handler(unsigned int ea_reason, uint64_t syndrome, void *cookie, 32 void *handle, uint64_t flags) 33 { 34 unsigned int level = (unsigned int)GET_EL(read_spsr_el3()); 35 36 /* 37 * Asynchronous External Abort with syndrome 0xbf000002 on Cortex A53 38 * core means SError interrupt caused by AXI SLVERR on external access. 39 * 40 * In most cases this indicates a bug in U-Boot or Linux kernel driver 41 * pci-aardvark.c which implements access to A3700 PCIe config space. 42 * Driver does not wait for PCIe PIO transfer completion and try to 43 * start a new PCIe PIO transfer while previous has not finished yet. 44 * A3700 PCIe controller in this case sends SLVERR via AXI which results 45 * in a fatal Asynchronous SError interrupt on Cortex A53 CPU. 46 * 47 * Following patches fix that bug in U-Boot and Linux kernel drivers: 48 * https://source.denx.de/u-boot/u-boot/-/commit/eccbd4ad8e4e182638eafbfb87ac139c04f24a01 49 * https://git.kernel.org/stable/c/f18139966d072dab8e4398c95ce955a9742e04f7 50 * 51 * As a hacky workaround for unpatched U-Boot and Linux kernel drivers 52 * ignore all asynchronous aborts with that syndrome value received on 53 * CPU from level lower than EL3. 54 * 55 * Because these aborts are delivered on CPU asynchronously, they are 56 * imprecise and we cannot check the real reason of abort and neither 57 * who and why sent this abort. We expect that on A3700 it is always 58 * PCIe controller. 59 * 60 * Hence ignoring all aborts with this syndrome value is just a giant 61 * hack that we need only because of bugs in old U-Boot and Linux kernel 62 * versions and because it was decided that TF-A would implement this 63 * hack for U-Boot and Linux kernel it in this way. New patched U-Boot 64 * and kernel versions do not need it anymore. 65 * 66 * Links to discussion about this workaround: 67 * https://lore.kernel.org/linux-pci/20190316161243.29517-1-repk@triplefau.lt/ 68 * https://lore.kernel.org/linux-pci/971be151d24312cc533989a64bd454b4@www.loen.fr/ 69 * https://review.trustedfirmware.org/c/TF-A/trusted-firmware-a/+/1541 70 */ 71 if (level < MODE_EL3 && ea_reason == ERROR_EA_ASYNC && 72 syndrome == A53_SERR_INT_AXI_SLVERR_ON_EXTERNAL_ACCESS) { 73 ERROR_NL(); 74 ERROR("Ignoring Asynchronous External Abort with" 75 " syndrome 0x%llx received on 0x%lx from %s\n", 76 syndrome, read_mpidr_el1(), get_el_str(level)); 77 ERROR("SError interrupt: AXI SLVERR on external access\n"); 78 ERROR("This indicates a bug in pci-aardvark.c driver\n"); 79 ERROR("Please update U-Boot/Linux to the latest version\n"); 80 ERROR_NL(); 81 console_flush(); 82 return; 83 } 84 85 plat_default_ea_handler(ea_reason, syndrome, cookie, handle, flags); 86 } 87