diff options
Diffstat (limited to 'kernel/arch/arm/mach-mvebu/coherency.c')
| -rw-r--r-- | kernel/arch/arm/mach-mvebu/coherency.c | 252 |
1 files changed, 252 insertions, 0 deletions
diff --git a/kernel/arch/arm/mach-mvebu/coherency.c b/kernel/arch/arm/mach-mvebu/coherency.c new file mode 100644 index 000000000..e46e9ea1e --- /dev/null +++ b/kernel/arch/arm/mach-mvebu/coherency.c @@ -0,0 +1,252 @@ +/* + * Coherency fabric (Aurora) support for Armada 370, 375, 38x and XP + * platforms. + * + * Copyright (C) 2012 Marvell + * + * Yehuda Yitschak <yehuday@marvell.com> + * Gregory Clement <gregory.clement@free-electrons.com> + * Thomas Petazzoni <thomas.petazzoni@free-electrons.com> + * + * 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 <linux/kernel.h> +#include <linux/init.h> +#include <linux/of_address.h> +#include <linux/io.h> +#include <linux/smp.h> +#include <linux/dma-mapping.h> +#include <linux/platform_device.h> +#include <linux/slab.h> +#include <linux/mbus.h> +#include <linux/pci.h> +#include <asm/smp_plat.h> +#include <asm/cacheflush.h> +#include <asm/mach/map.h> +#include <asm/dma-mapping.h> +#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 |