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 void plat_ea_handler(unsigned int ea_reason, uint64_t syndrome, void *cookie, 28 void *handle, uint64_t flags) 29 { 30 unsigned int level = (unsigned int)GET_EL(read_spsr_el3()); 31 32 /* 33 * Asynchronous External Abort with syndrome 0xbf000002 on Cortex A53 34 * core means SError interrupt caused by AXI SLVERR on external access. 35 * 36 * In most cases this indicates a bug in U-Boot or Linux kernel driver 37 * pci-aardvark.c which implements access to A3700 PCIe config space. 38 * Driver does not wait for PCIe PIO transfer completion and try to 39 * start a new PCIe PIO transfer while previous has not finished yet. 40 * A3700 PCIe controller in this case sends SLVERR via AXI which results 41 * in a fatal Asynchronous SError interrupt on Cortex A53 CPU. 42 * 43 * Following patches fix that bug in U-Boot and Linux kernel drivers: 44 * https://source.denx.de/u-boot/u-boot/-/commit/eccbd4ad8e4e182638eafbfb87ac139c04f24a01 45 * https://git.kernel.org/stable/c/f18139966d072dab8e4398c95ce955a9742e04f7 46 * 47 * As a hacky workaround for unpatched U-Boot and Linux kernel drivers 48 * ignore all asynchronous aborts with that syndrome value received on 49 * CPU from level lower than EL3. 50 * 51 * Because these aborts are delivered on CPU asynchronously, they are 52 * imprecise and we cannot check the real reason of abort and neither 53 * who and why sent this abort. We expect that on A3700 it is always 54 * PCIe controller. 55 * 56 * Hence ignoring all aborts with this syndrome value is just a giant 57 * hack that we need only because of bugs in old U-Boot and Linux kernel 58 * versions and because it was decided that TF-A would implement this 59 * hack for U-Boot and Linux kernel it in this way. New patched U-Boot 60 * and kernel versions do not need it anymore. 61 * 62 * Links to discussion about this workaround: 63 * https://lore.kernel.org/linux-pci/20190316161243.29517-1-repk@triplefau.lt/ 64 * https://lore.kernel.org/linux-pci/971be151d24312cc533989a64bd454b4@www.loen.fr/ 65 * https://review.trustedfirmware.org/c/TF-A/trusted-firmware-a/+/1541 66 */ 67 if (level < MODE_EL3 && ea_reason == ERROR_EA_ASYNC && 68 syndrome == A53_SERR_INT_AXI_SLVERR_ON_EXTERNAL_ACCESS) { 69 ERROR_NL(); 70 ERROR("Ignoring Asynchronous External Abort with" 71 " syndrome 0x%llx received on 0x%lx from %s\n", 72 syndrome, read_mpidr_el1(), get_el_str(level)); 73 ERROR("SError interrupt: AXI SLVERR on external access\n"); 74 ERROR("This indicates a bug in pci-aardvark.c driver\n"); 75 ERROR("Please update U-Boot/Linux to the latest version\n"); 76 ERROR_NL(); 77 console_flush(); 78 return; 79 } 80 81 plat_default_ea_handler(ea_reason, syndrome, cookie, handle, flags); 82 } 83