--- /dev/null
+/*
+ * 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
Code Review / kvmfornfv.git / blobdiff