1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * Coherency fabric (Aurora) support for Armada 370, 375, 38x and XP 4 * platforms. 5 * 6 * Copyright (C) 2012 Marvell 7 * 8 * Yehuda Yitschak <yehuday@marvell.com> 9 * Gregory Clement <gregory.clement@free-electrons.com> 10 * Thomas Petazzoni <thomas.petazzoni@free-electrons.com> 11 * 12 * The Armada 370, 375, 38x and XP SOCs have a coherency fabric which is 13 * responsible for ensuring hardware coherency between all CPUs and between 14 * CPUs and I/O masters. This file initializes the coherency fabric and 15 * supplies basic routines for configuring and controlling hardware coherency 16 */ 17 18 #define pr_fmt(fmt) "mvebu-coherency: " fmt 19 20 #include <linux/kernel.h> 21 #include <linux/init.h> 22 #include <linux/of_address.h> 23 #include <linux/io.h> 24 #include <linux/smp.h> 25 #include <linux/dma-map-ops.h> 26 #include <linux/platform_device.h> 27 #include <linux/slab.h> 28 #include <linux/mbus.h> 29 #include <linux/pci.h> 30 #include <asm/smp_plat.h> 31 #include <asm/cacheflush.h> 32 #include <asm/mach/map.h> 33 #include <asm/dma-mapping.h> 34 #include "coherency.h" 35 #include "mvebu-soc-id.h" 36 37 unsigned long coherency_phys_base; 38 void __iomem *coherency_base; 39 static void __iomem *coherency_cpu_base; 40 static void __iomem *cpu_config_base; 41 42 /* Coherency fabric registers */ 43 #define IO_SYNC_BARRIER_CTL_OFFSET 0x0 44 45 enum { 46 COHERENCY_FABRIC_TYPE_NONE, 47 COHERENCY_FABRIC_TYPE_ARMADA_370_XP, 48 COHERENCY_FABRIC_TYPE_ARMADA_375, 49 COHERENCY_FABRIC_TYPE_ARMADA_380, 50 }; 51 52 static const struct of_device_id of_coherency_table[] = { 53 {.compatible = "marvell,coherency-fabric", 54 .data = (void *) COHERENCY_FABRIC_TYPE_ARMADA_370_XP }, 55 {.compatible = "marvell,armada-375-coherency-fabric", 56 .data = (void *) COHERENCY_FABRIC_TYPE_ARMADA_375 }, 57 {.compatible = "marvell,armada-380-coherency-fabric", 58 .data = (void *) COHERENCY_FABRIC_TYPE_ARMADA_380 }, 59 { /* end of list */ }, 60 }; 61 62 /* Functions defined in coherency_ll.S */ 63 int ll_enable_coherency(void); 64 void ll_add_cpu_to_smp_group(void); 65 66 #define CPU_CONFIG_SHARED_L2 BIT(16) 67 68 /* 69 * Disable the "Shared L2 Present" bit in CPU Configuration register 70 * on Armada XP. 71 * 72 * The "Shared L2 Present" bit affects the "level of coherence" value 73 * in the clidr CP15 register. Cache operation functions such as 74 * "flush all" and "invalidate all" operate on all the cache levels 75 * that included in the defined level of coherence. When HW I/O 76 * coherency is used, this bit causes unnecessary flushes of the L2 77 * cache. 78 */ 79 static void armada_xp_clear_shared_l2(void) 80 { 81 u32 reg; 82 83 if (!cpu_config_base) 84 return; 85 86 reg = readl(cpu_config_base); 87 reg &= ~CPU_CONFIG_SHARED_L2; 88 writel(reg, cpu_config_base); 89 } 90 91 static int mvebu_hwcc_notifier(struct notifier_block *nb, 92 unsigned long event, void *__dev) 93 { 94 struct device *dev = __dev; 95 96 if (event != BUS_NOTIFY_ADD_DEVICE) 97 return NOTIFY_DONE; 98 dev->dma_coherent = true; 99 100 return NOTIFY_OK; 101 } 102 103 static struct notifier_block mvebu_hwcc_nb = { 104 .notifier_call = mvebu_hwcc_notifier, 105 }; 106 107 static struct notifier_block mvebu_hwcc_pci_nb __maybe_unused = { 108 .notifier_call = mvebu_hwcc_notifier, 109 }; 110 111 static int armada_xp_clear_l2_starting(unsigned int cpu) 112 { 113 armada_xp_clear_shared_l2(); 114 return 0; 115 } 116 117 static void __init armada_370_coherency_init(struct device_node *np) 118 { 119 struct resource res; 120 struct device_node *cpu_config_np; 121 122 of_address_to_resource(np, 0, &res); 123 coherency_phys_base = res.start; 124 /* 125 * Ensure secondary CPUs will see the updated value, 126 * which they read before they join the coherency 127 * fabric, and therefore before they are coherent with 128 * the boot CPU cache. 129 */ 130 sync_cache_w(&coherency_phys_base); 131 coherency_base = of_iomap(np, 0); 132 coherency_cpu_base = of_iomap(np, 1); 133 134 cpu_config_np = of_find_compatible_node(NULL, NULL, 135 "marvell,armada-xp-cpu-config"); 136 if (!cpu_config_np) 137 goto exit; 138 139 cpu_config_base = of_iomap(cpu_config_np, 0); 140 if (!cpu_config_base) { 141 of_node_put(cpu_config_np); 142 goto exit; 143 } 144 145 of_node_put(cpu_config_np); 146 147 cpuhp_setup_state_nocalls(CPUHP_AP_ARM_MVEBU_COHERENCY, 148 "arm/mvebu/coherency:starting", 149 armada_xp_clear_l2_starting, NULL); 150 exit: 151 set_cpu_coherent(); 152 } 153 154 /* 155 * This ioremap hook is used on Armada 375/38x to ensure that all MMIO 156 * areas are mapped as MT_UNCACHED instead of MT_DEVICE. This is 157 * needed for the HW I/O coherency mechanism to work properly without 158 * deadlock. 159 */ 160 static void __iomem * 161 armada_wa_ioremap_caller(phys_addr_t phys_addr, size_t size, 162 unsigned int mtype, void *caller) 163 { 164 mtype = MT_UNCACHED; 165 return __arm_ioremap_caller(phys_addr, size, mtype, caller); 166 } 167 168 static void __init armada_375_380_coherency_init(struct device_node *np) 169 { 170 struct device_node *cache_dn; 171 172 coherency_cpu_base = of_iomap(np, 0); 173 arch_ioremap_caller = armada_wa_ioremap_caller; 174 pci_ioremap_set_mem_type(MT_UNCACHED); 175 176 /* 177 * We should switch the PL310 to I/O coherency mode only if 178 * I/O coherency is actually enabled. 179 */ 180 if (!coherency_available()) 181 return; 182 183 /* 184 * Add the PL310 property "arm,io-coherent". This makes sure the 185 * outer sync operation is not used, which allows to 186 * workaround the system erratum that causes deadlocks when 187 * doing PCIe in an SMP situation on Armada 375 and Armada 188 * 38x. 189 */ 190 for_each_compatible_node(cache_dn, NULL, "arm,pl310-cache") { 191 struct property *p; 192 193 p = kzalloc(sizeof(*p), GFP_KERNEL); 194 p->name = kstrdup("arm,io-coherent", GFP_KERNEL); 195 of_add_property(cache_dn, p); 196 } 197 } 198 199 static int coherency_type(void) 200 { 201 struct device_node *np; 202 const struct of_device_id *match; 203 int type; 204 205 /* 206 * The coherency fabric is needed: 207 * - For coherency between processors on Armada XP, so only 208 * when SMP is enabled. 209 * - For coherency between the processor and I/O devices, but 210 * this coherency requires many pre-requisites (write 211 * allocate cache policy, shareable pages, SMP bit set) that 212 * are only meant in SMP situations. 213 * 214 * Note that this means that on Armada 370, there is currently 215 * no way to use hardware I/O coherency, because even when 216 * CONFIG_SMP is enabled, is_smp() returns false due to the 217 * Armada 370 being a single-core processor. To lift this 218 * limitation, we would have to find a way to make the cache 219 * policy set to write-allocate (on all Armada SoCs), and to 220 * set the shareable attribute in page tables (on all Armada 221 * SoCs except the Armada 370). Unfortunately, such decisions 222 * are taken very early in the kernel boot process, at a point 223 * where we don't know yet on which SoC we are running. 224 225 */ 226 if (!is_smp()) 227 return COHERENCY_FABRIC_TYPE_NONE; 228 229 np = of_find_matching_node_and_match(NULL, of_coherency_table, &match); 230 if (!np) 231 return COHERENCY_FABRIC_TYPE_NONE; 232 233 type = (int) match->data; 234 235 of_node_put(np); 236 237 return type; 238 } 239 240 int set_cpu_coherent(void) 241 { 242 int type = coherency_type(); 243 244 if (type == COHERENCY_FABRIC_TYPE_ARMADA_370_XP) { 245 if (!coherency_base) { 246 pr_warn("Can't make current CPU cache coherent.\n"); 247 pr_warn("Coherency fabric is not initialized\n"); 248 return 1; 249 } 250 251 armada_xp_clear_shared_l2(); 252 ll_add_cpu_to_smp_group(); 253 return ll_enable_coherency(); 254 } 255 256 return 0; 257 } 258 259 int coherency_available(void) 260 { 261 return coherency_type() != COHERENCY_FABRIC_TYPE_NONE; 262 } 263 264 int __init coherency_init(void) 265 { 266 int type = coherency_type(); 267 struct device_node *np; 268 269 np = of_find_matching_node(NULL, of_coherency_table); 270 271 if (type == COHERENCY_FABRIC_TYPE_ARMADA_370_XP) 272 armada_370_coherency_init(np); 273 else if (type == COHERENCY_FABRIC_TYPE_ARMADA_375 || 274 type == COHERENCY_FABRIC_TYPE_ARMADA_380) 275 armada_375_380_coherency_init(np); 276 277 of_node_put(np); 278 279 return 0; 280 } 281 282 static int __init coherency_late_init(void) 283 { 284 if (coherency_available()) 285 bus_register_notifier(&platform_bus_type, 286 &mvebu_hwcc_nb); 287 return 0; 288 } 289 290 postcore_initcall(coherency_late_init); 291 292 #if IS_ENABLED(CONFIG_PCI) 293 static int __init coherency_pci_init(void) 294 { 295 if (coherency_available()) 296 bus_register_notifier(&pci_bus_type, 297 &mvebu_hwcc_pci_nb); 298 return 0; 299 } 300 301 arch_initcall(coherency_pci_init); 302 #endif 303