/* * Coherency fabric (Aurora) support for Armada 370, 375, 38x and XP * platforms. * * Copyright (C) 2012 Marvell * * Yehuda Yitschak * Gregory Clement * Thomas Petazzoni * * This file is licensed under the terms of the GNU General Public * License version 2. This program is licensed "as is" without any * warranty of any kind, whether express or implied. * * The Armada 370, 375, 38x and XP SOCs have a coherency fabric which is * responsible for ensuring hardware coherency between all CPUs and between * CPUs and I/O masters. This file initializes the coherency fabric and * supplies basic routines for configuring and controlling hardware coherency */ #define pr_fmt(fmt) "mvebu-coherency: " fmt #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include "coherency.h" #include "mvebu-soc-id.h" unsigned long coherency_phys_base; void __iomem *coherency_base; static void __iomem *coherency_cpu_base; /* Coherency fabric registers */ #define IO_SYNC_BARRIER_CTL_OFFSET 0x0 enum { COHERENCY_FABRIC_TYPE_NONE, COHERENCY_FABRIC_TYPE_ARMADA_370_XP, COHERENCY_FABRIC_TYPE_ARMADA_375, COHERENCY_FABRIC_TYPE_ARMADA_380, }; static const struct of_device_id of_coherency_table[] = { {.compatible = "marvell,coherency-fabric", .data = (void *) COHERENCY_FABRIC_TYPE_ARMADA_370_XP }, {.compatible = "marvell,armada-375-coherency-fabric", .data = (void *) COHERENCY_FABRIC_TYPE_ARMADA_375 }, {.compatible = "marvell,armada-380-coherency-fabric", .data = (void *) COHERENCY_FABRIC_TYPE_ARMADA_380 }, { /* end of list */ }, }; /* Functions defined in coherency_ll.S */ int ll_enable_coherency(void); void ll_add_cpu_to_smp_group(void); int set_cpu_coherent(void) { if (!coherency_base) { pr_warn("Can't make current CPU cache coherent.\n"); pr_warn("Coherency fabric is not initialized\n"); return 1; } ll_add_cpu_to_smp_group(); return ll_enable_coherency(); } static int mvebu_hwcc_notifier(struct notifier_block *nb, unsigned long event, void *__dev) { struct device *dev = __dev; if (event != BUS_NOTIFY_ADD_DEVICE) return NOTIFY_DONE; set_dma_ops(dev, &arm_coherent_dma_ops); return NOTIFY_OK; } static struct notifier_block mvebu_hwcc_nb = { .notifier_call = mvebu_hwcc_notifier, }; static struct notifier_block mvebu_hwcc_pci_nb = { .notifier_call = mvebu_hwcc_notifier, }; static void __init armada_370_coherency_init(struct device_node *np) { struct resource res; of_address_to_resource(np, 0, &res); coherency_phys_base = res.start; /* * Ensure secondary CPUs will see the updated value, * which they read before they join the coherency * fabric, and therefore before they are coherent with * the boot CPU cache. */ sync_cache_w(&coherency_phys_base); coherency_base = of_iomap(np, 0); coherency_cpu_base = of_iomap(np, 1); set_cpu_coherent(); } /* * This ioremap hook is used on Armada 375/38x to ensure that PCIe * memory areas are mapped as MT_UNCACHED instead of MT_DEVICE. This * is needed as a workaround for a deadlock issue between the PCIe * interface and the cache controller. */ static void __iomem * armada_pcie_wa_ioremap_caller(phys_addr_t phys_addr, size_t size, unsigned int mtype, void *caller) { struct resource pcie_mem; mvebu_mbus_get_pcie_mem_aperture(&pcie_mem); if (pcie_mem.start <= phys_addr && (phys_addr + size) <= pcie_mem.end) mtype = MT_UNCACHED; return __arm_ioremap_caller(phys_addr, size, mtype, caller); } static void __init armada_375_380_coherency_init(struct device_node *np) { struct device_node *cache_dn; coherency_cpu_base = of_iomap(np, 0); arch_ioremap_caller = armada_pcie_wa_ioremap_caller; /* * We should switch the PL310 to I/O coherency mode only if * I/O coherency is actually enabled. */ if (!coherency_available()) return; /* * Add the PL310 property "arm,io-coherent". This makes sure the * outer sync operation is not used, which allows to * workaround the system erratum that causes deadlocks when * doing PCIe in an SMP situation on Armada 375 and Armada * 38x. */ for_each_compatible_node(cache_dn, NULL, "arm,pl310-cache") { struct property *p; p = kzalloc(sizeof(*p), GFP_KERNEL); p->name = kstrdup("arm,io-coherent", GFP_KERNEL); of_add_property(cache_dn, p); } } static int coherency_type(void) { struct device_node *np; const struct of_device_id *match; int type; /* * The coherency fabric is needed: * - For coherency between processors on Armada XP, so only * when SMP is enabled. * - For coherency between the processor and I/O devices, but * this coherency requires many pre-requisites (write * allocate cache policy, shareable pages, SMP bit set) that * are only meant in SMP situations. * * Note that this means that on Armada 370, there is currently * no way to use hardware I/O coherency, because even when * CONFIG_SMP is enabled, is_smp() returns false due to the * Armada 370 being a single-core processor. To lift this * limitation, we would have to find a way to make the cache * policy set to write-allocate (on all Armada SoCs), and to * set the shareable attribute in page tables (on all Armada * SoCs except the Armada 370). Unfortunately, such decisions * are taken very early in the kernel boot process, at a point * where we don't know yet on which SoC we are running. */ if (!is_smp()) return COHERENCY_FABRIC_TYPE_NONE; np = of_find_matching_node_and_match(NULL, of_coherency_table, &match); if (!np) return COHERENCY_FABRIC_TYPE_NONE; type = (int) match->data; of_node_put(np); return type; } int coherency_available(void) { return coherency_type() != COHERENCY_FABRIC_TYPE_NONE; } int __init coherency_init(void) { int type = coherency_type(); struct device_node *np; np = of_find_matching_node(NULL, of_coherency_table); if (type == COHERENCY_FABRIC_TYPE_ARMADA_370_XP) armada_370_coherency_init(np); else if (type == COHERENCY_FABRIC_TYPE_ARMADA_375 || type == COHERENCY_FABRIC_TYPE_ARMADA_380) armada_375_380_coherency_init(np); of_node_put(np); return 0; } static int __init coherency_late_init(void) { if (coherency_available()) bus_register_notifier(&platform_bus_type, &mvebu_hwcc_nb); return 0; } postcore_initcall(coherency_late_init); #if IS_ENABLED(CONFIG_PCI) static int __init coherency_pci_init(void) { if (coherency_available()) bus_register_notifier(&pci_bus_type, &mvebu_hwcc_pci_nb); return 0; } arch_initcall(coherency_pci_init); #endif