James Hogan | 99ef7c2 | 2012-10-09 10:54:17 +0100 | [diff] [blame] | 1 | #include <linux/init.h> |
| 2 | #include <linux/kernel.h> |
| 3 | #include <linux/delay.h> |
| 4 | |
| 5 | #include <asm/l2cache.h> |
| 6 | #include <asm/metag_isa.h> |
| 7 | |
| 8 | /* If non-0, then initialise the L2 cache */ |
| 9 | static int l2cache_init = 1; |
| 10 | /* If non-0, then initialise the L2 cache prefetch */ |
| 11 | static int l2cache_init_pf = 1; |
| 12 | |
| 13 | int l2c_pfenable; |
| 14 | |
| 15 | static volatile u32 l2c_testdata[16] __initdata __aligned(64); |
| 16 | |
| 17 | static int __init parse_l2cache(char *p) |
| 18 | { |
| 19 | char *cp = p; |
| 20 | |
| 21 | if (get_option(&cp, &l2cache_init) != 1) { |
| 22 | pr_err("Bad l2cache parameter (%s)\n", p); |
| 23 | return 1; |
| 24 | } |
| 25 | return 0; |
| 26 | } |
| 27 | early_param("l2cache", parse_l2cache); |
| 28 | |
| 29 | static int __init parse_l2cache_pf(char *p) |
| 30 | { |
| 31 | char *cp = p; |
| 32 | |
| 33 | if (get_option(&cp, &l2cache_init_pf) != 1) { |
| 34 | pr_err("Bad l2cache_pf parameter (%s)\n", p); |
| 35 | return 1; |
| 36 | } |
| 37 | return 0; |
| 38 | } |
| 39 | early_param("l2cache_pf", parse_l2cache_pf); |
| 40 | |
| 41 | static int __init meta_l2c_setup(void) |
| 42 | { |
| 43 | /* |
| 44 | * If the L2 cache isn't even present, don't do anything, but say so in |
| 45 | * the log. |
| 46 | */ |
| 47 | if (!meta_l2c_is_present()) { |
| 48 | pr_info("L2 Cache: Not present\n"); |
| 49 | return 0; |
| 50 | } |
| 51 | |
| 52 | /* |
| 53 | * Check whether the line size is recognised. |
| 54 | */ |
| 55 | if (!meta_l2c_linesize()) { |
| 56 | pr_warn_once("L2 Cache: unknown line size id (config=0x%08x)\n", |
| 57 | meta_l2c_config()); |
| 58 | } |
| 59 | |
| 60 | /* |
| 61 | * Initialise state. |
| 62 | */ |
| 63 | l2c_pfenable = _meta_l2c_pf_is_enabled(); |
| 64 | |
| 65 | /* |
| 66 | * Enable the L2 cache and print to log whether it was already enabled |
| 67 | * by the bootloader. |
| 68 | */ |
| 69 | if (l2cache_init) { |
| 70 | pr_info("L2 Cache: Enabling... "); |
| 71 | if (meta_l2c_enable()) |
| 72 | pr_cont("already enabled\n"); |
| 73 | else |
| 74 | pr_cont("done\n"); |
| 75 | } else { |
| 76 | pr_info("L2 Cache: Not enabling\n"); |
| 77 | } |
| 78 | |
| 79 | /* |
| 80 | * Enable L2 cache prefetch. |
| 81 | */ |
| 82 | if (l2cache_init_pf) { |
| 83 | pr_info("L2 Cache: Enabling prefetch... "); |
| 84 | if (meta_l2c_pf_enable(1)) |
| 85 | pr_cont("already enabled\n"); |
| 86 | else |
| 87 | pr_cont("done\n"); |
| 88 | } else { |
| 89 | pr_info("L2 Cache: Not enabling prefetch\n"); |
| 90 | } |
| 91 | |
| 92 | return 0; |
| 93 | } |
| 94 | core_initcall(meta_l2c_setup); |
| 95 | |
| 96 | int meta_l2c_disable(void) |
| 97 | { |
| 98 | unsigned long flags; |
| 99 | int en; |
| 100 | |
| 101 | if (!meta_l2c_is_present()) |
| 102 | return 1; |
| 103 | |
| 104 | /* |
| 105 | * Prevent other threads writing during the writeback, otherwise the |
| 106 | * writes will get "lost" when the L2 is disabled. |
| 107 | */ |
| 108 | __global_lock2(flags); |
| 109 | en = meta_l2c_is_enabled(); |
| 110 | if (likely(en)) { |
| 111 | _meta_l2c_pf_enable(0); |
| 112 | wr_fence(); |
| 113 | _meta_l2c_purge(); |
| 114 | _meta_l2c_enable(0); |
| 115 | } |
| 116 | __global_unlock2(flags); |
| 117 | |
| 118 | return !en; |
| 119 | } |
| 120 | |
| 121 | int meta_l2c_enable(void) |
| 122 | { |
| 123 | unsigned long flags; |
| 124 | int en; |
| 125 | |
| 126 | if (!meta_l2c_is_present()) |
| 127 | return 0; |
| 128 | |
| 129 | /* |
| 130 | * Init (clearing the L2) can happen while the L2 is disabled, so other |
| 131 | * threads are safe to continue executing, however we must not init the |
| 132 | * cache if it's already enabled (dirty lines would be discarded), so |
| 133 | * this operation should still be atomic with other threads. |
| 134 | */ |
| 135 | __global_lock1(flags); |
| 136 | en = meta_l2c_is_enabled(); |
| 137 | if (likely(!en)) { |
| 138 | _meta_l2c_init(); |
| 139 | _meta_l2c_enable(1); |
| 140 | _meta_l2c_pf_enable(l2c_pfenable); |
| 141 | } |
| 142 | __global_unlock1(flags); |
| 143 | |
| 144 | return en; |
| 145 | } |
| 146 | |
| 147 | int meta_l2c_pf_enable(int pfenable) |
| 148 | { |
| 149 | unsigned long flags; |
| 150 | int en = l2c_pfenable; |
| 151 | |
| 152 | if (!meta_l2c_is_present()) |
| 153 | return 0; |
| 154 | |
| 155 | /* |
| 156 | * We read modify write the enable register, so this operation must be |
| 157 | * atomic with other threads. |
| 158 | */ |
| 159 | __global_lock1(flags); |
| 160 | en = l2c_pfenable; |
| 161 | l2c_pfenable = pfenable; |
| 162 | if (meta_l2c_is_enabled()) |
| 163 | _meta_l2c_pf_enable(pfenable); |
| 164 | __global_unlock1(flags); |
| 165 | |
| 166 | return en; |
| 167 | } |
| 168 | |
| 169 | int meta_l2c_flush(void) |
| 170 | { |
| 171 | unsigned long flags; |
| 172 | int en; |
| 173 | |
| 174 | /* |
| 175 | * Prevent other threads writing during the writeback. This also |
| 176 | * involves read modify writes. |
| 177 | */ |
| 178 | __global_lock2(flags); |
| 179 | en = meta_l2c_is_enabled(); |
| 180 | if (likely(en)) { |
| 181 | _meta_l2c_pf_enable(0); |
| 182 | wr_fence(); |
| 183 | _meta_l2c_purge(); |
| 184 | _meta_l2c_enable(0); |
| 185 | _meta_l2c_init(); |
| 186 | _meta_l2c_enable(1); |
| 187 | _meta_l2c_pf_enable(l2c_pfenable); |
| 188 | } |
| 189 | __global_unlock2(flags); |
| 190 | |
| 191 | return !en; |
| 192 | } |