arch/arm/mm/cache-feroceon-l2.c

   1 /*
   2  * arch/arm/mm/cache-feroceon-l2.c - Feroceon L2 cache controller support
   3  *
   4  * Copyright (C) 2008 Marvell Semiconductor
   5  *
   6  * This file is licensed under the terms of the GNU General Public
   7  * License version 2.  This program is licensed "as is" without any
   8  * warranty of any kind, whether express or implied.
   9  *
  10  * References:
  11  * - Unified Layer 2 Cache for Feroceon CPU Cores,
  12  *   Document ID MV-S104858-00, Rev. A, October 23 2007.
  13  */
  14
  15 #include <linux/init.h>
  16 #include <linux/of.h>
  17 #include <linux/of_address.h>
  18 #include <linux/highmem.h>
  19 #include <linux/io.h>
  20 #include <asm/cacheflush.h>
  21 #include <asm/cp15.h>
  22 #include <asm/hardware/cache-feroceon-l2.h>
  23
  24 #define L2_WRITETHROUGH_KIRKWOOD        BIT(4)
  25
  26 /*
  27  * Low-level cache maintenance operations.
  28  *
  29  * As well as the regular 'clean/invalidate/flush L2 cache line by
  30  * MVA' instructions, the Feroceon L2 cache controller also features
  31  * 'clean/invalidate L2 range by MVA' operations.
  32  *
  33  * Cache range operations are initiated by writing the start and
  34  * end addresses to successive cp15 registers, and process every
  35  * cache line whose first byte address lies in the inclusive range
  36  * [start:end].
  37  *
  38  * The cache range operations stall the CPU pipeline until completion.
  39  *
  40  * The range operations require two successive cp15 writes, in
  41  * between which we don't want to be preempted.
  42  */
  43
  44 static inline unsigned long l2_get_va(unsigned long paddr)
  45 {
  46 #ifdef CONFIG_HIGHMEM
  47         /*
  48          * Because range ops can't be done on physical addresses,
  49          * we simply install a virtual mapping for it only for the
  50          * TLB lookup to occur, hence no need to flush the untouched
  51          * memory mapping afterwards (note: a cache flush may happen
  52          * in some circumstances depending on the path taken in kunmap_atomic).
  53          */
  54         void *vaddr = kmap_atomic_pfn(paddr >> PAGE_SHIFT);
  55         return (unsigned long)vaddr + (paddr & ~PAGE_MASK);
  56 #else
  57         return __phys_to_virt(paddr);
  58 #endif
  59 }
  60
  61 static inline void l2_put_va(unsigned long vaddr)
  62 {
  63 #ifdef CONFIG_HIGHMEM
  64         kunmap_atomic((void *)vaddr);
  65 #endif
  66 }
  67
  68 static inline void l2_clean_pa(unsigned long addr)
  69 {
  70         __asm__("mcr p15, 1, %0, c15, c9, 3" : : "r" (addr));
  71 }
  72
  73 static inline void l2_clean_pa_range(unsigned long start, unsigned long end)
  74 {
  75         unsigned long va_start, va_end, flags;
  76
  77         /*
  78          * Make sure 'start' and 'end' reference the same page, as
  79          * L2 is PIPT and range operations only do a TLB lookup on
  80          * the start address.
  81          */
  82         BUG_ON((start ^ end) >> PAGE_SHIFT);
  83
  84         va_start = l2_get_va(start);
  85         va_end = va_start + (end - start);
  86         raw_local_irq_save(flags);
  87         __asm__("mcr p15, 1, %0, c15, c9, 4\n\t"
  88                 "mcr p15, 1, %1, c15, c9, 5"
  89                 : : "r" (va_start), "r" (va_end));
  90         raw_local_irq_restore(flags);
  91         l2_put_va(va_start);
  92 }
  93
  94 static inline void l2_clean_inv_pa(unsigned long addr)
  95 {
  96         __asm__("mcr p15, 1, %0, c15, c10, 3" : : "r" (addr));
  97 }
  98
  99 static inline void l2_inv_pa(unsigned long addr)
 100 {
 101         __asm__("mcr p15, 1, %0, c15, c11, 3" : : "r" (addr));
 102 }
 103
 104 static inline void l2_inv_pa_range(unsigned long start, unsigned long end)
 105 {
 106         unsigned long va_start, va_end, flags;
 107
 108         /*
 109          * Make sure 'start' and 'end' reference the same page, as
 110          * L2 is PIPT and range operations only do a TLB lookup on
 111          * the start address.
 112          */
 113         BUG_ON((start ^ end) >> PAGE_SHIFT);
 114
 115         va_start = l2_get_va(start);
 116         va_end = va_start + (end - start);
 117         raw_local_irq_save(flags);
 118         __asm__("mcr p15, 1, %0, c15, c11, 4\n\t"
 119                 "mcr p15, 1, %1, c15, c11, 5"
 120                 : : "r" (va_start), "r" (va_end));
 121         raw_local_irq_restore(flags);
 122         l2_put_va(va_start);
 123 }
 124
 125 static inline void l2_inv_all(void)
 126 {
 127         __asm__("mcr p15, 1, %0, c15, c11, 0" : : "r" (0));
 128 }
 129
 130 /*
 131  * Linux primitives.
 132  *
 133  * Note that the end addresses passed to Linux primitives are
 134  * noninclusive, while the hardware cache range operations use
 135  * inclusive start and end addresses.
 136  */
 137 #define CACHE_LINE_SIZE         32
 138 #define MAX_RANGE_SIZE          1024
 139
 140 static int l2_wt_override;
 141
 142 static unsigned long calc_range_end(unsigned long start, unsigned long end)
 143 {
 144         unsigned long range_end;
 145
 146         BUG_ON(start & (CACHE_LINE_SIZE - 1));
 147         BUG_ON(end & (CACHE_LINE_SIZE - 1));
 148
 149         /*
 150          * Try to process all cache lines between 'start' and 'end'.
 151          */
 152         range_end = end;
 153
 154         /*
 155          * Limit the number of cache lines processed at once,
 156          * since cache range operations stall the CPU pipeline
 157          * until completion.
 158          */
 159         if (range_end > start + MAX_RANGE_SIZE)
 160                 range_end = start + MAX_RANGE_SIZE;
 161
 162         /*
 163          * Cache range operations can't straddle a page boundary.
 164          */
 165         if (range_end > (start | (PAGE_SIZE - 1)) + 1)
 166                 range_end = (start | (PAGE_SIZE - 1)) + 1;
 167
 168         return range_end;
 169 }
 170
 171 static void feroceon_l2_inv_range(unsigned long start, unsigned long end)
 172 {
 173         /*
 174          * Clean and invalidate partial first cache line.
 175          */
 176         if (start & (CACHE_LINE_SIZE - 1)) {
 177                 l2_clean_inv_pa(start & ~(CACHE_LINE_SIZE - 1));
 178                 start = (start | (CACHE_LINE_SIZE - 1)) + 1;
 179         }
 180
 181         /*
 182          * Clean and invalidate partial last cache line.
 183          */
 184         if (start < end && end & (CACHE_LINE_SIZE - 1)) {
 185                 l2_clean_inv_pa(end & ~(CACHE_LINE_SIZE - 1));
 186                 end &= ~(CACHE_LINE_SIZE - 1);
 187         }
 188
 189         /*
 190          * Invalidate all full cache lines between 'start' and 'end'.
 191          */
 192         while (start < end) {
 193                 unsigned long range_end = calc_range_end(start, end);
 194                 l2_inv_pa_range(start, range_end - CACHE_LINE_SIZE);
 195                 start = range_end;
 196         }
 197
 198         dsb();
 199 }
 200
 201 static void feroceon_l2_clean_range(unsigned long start, unsigned long end)
 202 {
 203         /*
 204          * If L2 is forced to WT, the L2 will always be clean and we
 205          * don't need to do anything here.
 206          */
 207         if (!l2_wt_override) {
 208                 start &= ~(CACHE_LINE_SIZE - 1);
 209                 end = (end + CACHE_LINE_SIZE - 1) & ~(CACHE_LINE_SIZE - 1);
 210                 while (start != end) {
 211                         unsigned long range_end = calc_range_end(start, end);
 212                         l2_clean_pa_range(start, range_end - CACHE_LINE_SIZE);
 213                         start = range_end;
 214                 }
 215         }
 216
 217         dsb();
 218 }
 219
 220 static void feroceon_l2_flush_range(unsigned long start, unsigned long end)
 221 {
 222         start &= ~(CACHE_LINE_SIZE - 1);
 223         end = (end + CACHE_LINE_SIZE - 1) & ~(CACHE_LINE_SIZE - 1);
 224         while (start != end) {
 225                 unsigned long range_end = calc_range_end(start, end);
 226                 if (!l2_wt_override)
 227                         l2_clean_pa_range(start, range_end - CACHE_LINE_SIZE);
 228                 l2_inv_pa_range(start, range_end - CACHE_LINE_SIZE);
 229                 start = range_end;
 230         }
 231
 232         dsb();
 233 }
 234
 235
 236 /*
 237  * Routines to disable and re-enable the D-cache and I-cache at run
 238  * time.  These are necessary because the L2 cache can only be enabled
 239  * or disabled while the L1 Dcache and Icache are both disabled.
 240  */
 241 static int __init flush_and_disable_dcache(void)
 242 {
 243         u32 cr;
 244
 245         cr = get_cr();
 246         if (cr & CR_C) {
 247                 unsigned long flags;
 248
 249                 raw_local_irq_save(flags);
 250                 flush_cache_all();
 251                 set_cr(cr & ~CR_C);
 252                 raw_local_irq_restore(flags);
 253                 return 1;
 254         }
 255         return 0;
 256 }
 257
 258 static void __init enable_dcache(void)
 259 {
 260         u32 cr;
 261
 262         cr = get_cr();
 263         set_cr(cr | CR_C);
 264 }
 265
 266 static void __init __invalidate_icache(void)
 267 {
 268         __asm__("mcr p15, 0, %0, c7, c5, 0" : : "r" (0));
 269 }
 270
 271 static int __init invalidate_and_disable_icache(void)
 272 {
 273         u32 cr;
 274
 275         cr = get_cr();
 276         if (cr & CR_I) {
 277                 set_cr(cr & ~CR_I);
 278                 __invalidate_icache();
 279                 return 1;
 280         }
 281         return 0;
 282 }
 283
 284 static void __init enable_icache(void)
 285 {
 286         u32 cr;
 287
 288         cr = get_cr();
 289         set_cr(cr | CR_I);
 290 }
 291
 292 static inline u32 read_extra_features(void)
 293 {
 294         u32 u;
 295
 296         __asm__("mrc p15, 1, %0, c15, c1, 0" : "=r" (u));
 297
 298         return u;
 299 }
 300
 301 static inline void write_extra_features(u32 u)
 302 {
 303         __asm__("mcr p15, 1, %0, c15, c1, 0" : : "r" (u));
 304 }
 305
 306 static void __init disable_l2_prefetch(void)
 307 {
 308         u32 u;
 309
 310         /*
 311          * Read the CPU Extra Features register and verify that the
 312          * Disable L2 Prefetch bit is set.
 313          */
 314         u = read_extra_features();
 315         if (!(u & 0x01000000)) {
 316                 pr_info("Feroceon L2: Disabling L2 prefetch.\n");
 317                 write_extra_features(u | 0x01000000);
 318         }
 319 }
 320
 321 static void __init enable_l2(void)
 322 {
 323         u32 u;
 324
 325         u = read_extra_features();
 326         if (!(u & 0x00400000)) {
 327                 int i, d;
 328
 329                 pr_info("Feroceon L2: Enabling L2\n");
 330
 331                 d = flush_and_disable_dcache();
 332                 i = invalidate_and_disable_icache();
 333                 l2_inv_all();
 334                 write_extra_features(u | 0x00400000);
 335                 if (i)
 336                         enable_icache();
 337                 if (d)
 338                         enable_dcache();
 339         } else
 340                 pr_err(FW_BUG
 341                        "Feroceon L2: bootloader left the L2 cache on!\n");
 342 }
 343
 344 void __init feroceon_l2_init(int __l2_wt_override)
 345 {
 346         l2_wt_override = __l2_wt_override;
 347
 348         disable_l2_prefetch();
 349
 350         outer_cache.inv_range = feroceon_l2_inv_range;
 351         outer_cache.clean_range = feroceon_l2_clean_range;
 352         outer_cache.flush_range = feroceon_l2_flush_range;
 353
 354         enable_l2();
 355
 356         pr_info("Feroceon L2: Cache support initialised%s.\n",
 357                          l2_wt_override ? ", in WT override mode" : "");
 358 }
 359 #ifdef CONFIG_OF
 360 static const struct of_device_id feroceon_ids[] __initconst = {
 361         { .compatible = "marvell,kirkwood-cache"},
 362         { .compatible = "marvell,feroceon-cache"},
 363         {}
 364 };
 365
 366 int __init feroceon_of_init(void)
 367 {
 368         struct device_node *node;
 369         void __iomem *base;
 370         bool l2_wt_override = false;
 371
 372 #if defined(CONFIG_CACHE_FEROCEON_L2_WRITETHROUGH)
 373         l2_wt_override = true;
 374 #endif
 375
 376         node = of_find_matching_node(NULL, feroceon_ids);
 377         if (node && of_device_is_compatible(node, "marvell,kirkwood-cache")) {
 378                 base = of_iomap(node, 0);
 379                 if (!base)
 380                         return -ENOMEM;
 381
 382                 if (l2_wt_override)
 383                         writel(readl(base) | L2_WRITETHROUGH_KIRKWOOD, base);
 384                 else
 385                         writel(readl(base) & ~L2_WRITETHROUGH_KIRKWOOD, base);
 386         }
 387
 388         feroceon_l2_init(l2_wt_override);
 389
 390         return 0;
 391 }
 392 #endif