3 * Wolfgang Denk, DENX Software Engineering, wd@denx.de.
5 * See file CREDITS for list of people who contributed to this
8 * This program is free software; you can redistribute it and/or
9 * modify it under the terms of the GNU General Public License as
10 * published by the Free Software Foundation; either version 2 of
11 * the License, or (at your option) any later version.
13 * This program is distributed in the hope that it will be useful,
14 * but WITHOUT ANY WARRANTY; without even the implied warranty of
15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 * GNU General Public License for more details.
18 * You should have received a copy of the GNU General Public License
19 * along with this program; if not, write to the Free Software
20 * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
25 #include <asm/system.h>
27 #if !(defined(CONFIG_SYS_ICACHE_OFF) && defined(CONFIG_SYS_DCACHE_OFF))
29 #if defined(CONFIG_SYS_ARM_CACHE_WRITETHROUGH)
30 #define CACHE_SETUP 0x1a
32 #define CACHE_SETUP 0x1e
35 DECLARE_GLOBAL_DATA_PTR;
37 void __arm_init_before_mmu(void)
40 void arm_init_before_mmu(void)
41 __attribute__((weak, alias("__arm_init_before_mmu")));
43 static inline void dram_bank_mmu_setup(int bank)
45 u32 *page_table = (u32 *)gd->tlb_addr;
49 debug("%s: bank: %d\n", __func__, bank);
50 for (i = bd->bi_dram[bank].start >> 20;
51 i < (bd->bi_dram[bank].start + bd->bi_dram[bank].size) >> 20;
53 page_table[i] = i << 20 | (3 << 10) | CACHE_SETUP;
57 /* to activate the MMU we need to set up virtual memory: use 1M areas */
58 static inline void mmu_setup(void)
60 u32 *page_table = (u32 *)gd->tlb_addr;
64 arm_init_before_mmu();
65 /* Set up an identity-mapping for all 4GB, rw for everyone */
66 for (i = 0; i < 4096; i++)
67 page_table[i] = i << 20 | (3 << 10) | 0x12;
69 for (i = 0; i < CONFIG_NR_DRAM_BANKS; i++) {
70 dram_bank_mmu_setup(i);
73 /* Copy the page table address to cp15 */
74 asm volatile("mcr p15, 0, %0, c2, c0, 0"
75 : : "r" (page_table) : "memory");
76 /* Set the access control to all-supervisor */
77 asm volatile("mcr p15, 0, %0, c3, c0, 0"
79 /* and enable the mmu */
80 reg = get_cr(); /* get control reg. */
84 static int mmu_enabled(void)
86 return get_cr() & CR_M;
89 /* cache_bit must be either CR_I or CR_C */
90 static void cache_enable(uint32_t cache_bit)
94 /* The data cache is not active unless the mmu is enabled too */
95 if ((cache_bit == CR_C) && !mmu_enabled())
97 reg = get_cr(); /* get control reg. */
98 set_cr(reg | cache_bit);
101 /* cache_bit must be either CR_I or CR_C */
102 static void cache_disable(uint32_t cache_bit)
106 if (cache_bit == CR_C) {
107 /* if cache isn;t enabled no need to disable */
109 if ((reg & CR_C) != CR_C)
111 /* if disabling data cache, disable mmu too */
116 set_cr(reg & ~cache_bit);
120 #ifdef CONFIG_SYS_ICACHE_OFF
121 void icache_enable (void)
126 void icache_disable (void)
131 int icache_status (void)
133 return 0; /* always off */
136 void icache_enable(void)
141 void icache_disable(void)
146 int icache_status(void)
148 return (get_cr() & CR_I) != 0;
152 #ifdef CONFIG_SYS_DCACHE_OFF
153 void dcache_enable (void)
158 void dcache_disable (void)
163 int dcache_status (void)
165 return 0; /* always off */
168 void dcache_enable(void)
173 void dcache_disable(void)
178 int dcache_status(void)
180 return (get_cr() & CR_C) != 0;