fsl_booke_mmu.c

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/*
 * Modifications by Kumar Gala ([email protected]) to support
 * E500 Book E processors.
 *
 * Copyright 2004,2010 Freescale Semiconductor, Inc.
 *
 * This file contains the routines for initializing the MMU
 * on the 4xx series of chips.
 *  -- paulus
 *
 *  Derived from arch/ppc/mm/init.c:
 *    Copyright (C) 1995-1996 Gary Thomas ([email protected])
 *
 *  Modifications by Paul Mackerras (PowerMac) ([email protected])
 *  and Cort Dougan (PReP) ([email protected])
 *    Copyright (C) 1996 Paul Mackerras
 *
 *  Derived from "arch/i386/mm/init.c"
 *    Copyright (C) 1991, 1992, 1993, 1994  Linus Torvalds
 *
 *  This program is free software; you can redistribute it and/or
 *  modify it under the terms of the GNU General Public License
 *  as published by the Free Software Foundation; either version
 *  2 of the License, or (at your option) any later version.
 *
 */

#include <linux/signal.h>
#include <linux/sched.h>
#include <linux/kernel.h>
#include <linux/errno.h>
#include <linux/string.h>
#include <linux/types.h>
#include <linux/ptrace.h>
#include <linux/mman.h>
#include <linux/mm.h>
#include <linux/swap.h>
#include <linux/stddef.h>
#include <linux/vmalloc.h>
#include <linux/init.h>
#include <linux/delay.h>
#include <linux/highmem.h>
#include <linux/memblock.h>

#include <asm/pgalloc.h>
#include <asm/prom.h>
#include <asm/io.h>
#include <asm/mmu_context.h>
#include <asm/pgtable.h>
#include <asm/mmu.h>
#include <asm/uaccess.h>
#include <asm/smp.h>
#include <asm/machdep.h>
#include <asm/setup.h>

#include "mmu_decl.h"

unsigned int tlbcam_index;

#define NUM_TLBCAMS (64)
struct tlbcam TLBCAM[NUM_TLBCAMS];

struct tlbcamrange {
    unsigned long start;
    unsigned long limit;
    phys_addr_t phys;
} tlbcam_addrs[NUM_TLBCAMS];

extern unsigned int tlbcam_index;

unsigned long tlbcam_sz(int idx)
{
    return tlbcam_addrs[idx].limit - tlbcam_addrs[idx].start + 1;
}

/*
 * Return PA for this VA if it is mapped by a CAM, or 0
 */
phys_addr_t v_mapped_by_tlbcam(unsigned long va)
{
    int b;
    for (b = 0; b < tlbcam_index; ++b)
        if (va >= tlbcam_addrs[b].start && va < tlbcam_addrs[b].limit)
            return tlbcam_addrs[b].phys + (va - tlbcam_addrs[b].start);
    return 0;
}

/*
 * Return VA for a given PA or 0 if not mapped
 */
unsigned long p_mapped_by_tlbcam(phys_addr_t pa)
{
    int b;
    for (b = 0; b < tlbcam_index; ++b)
        if (pa >= tlbcam_addrs[b].phys
            && pa < (tlbcam_addrs[b].limit-tlbcam_addrs[b].start)
                      +tlbcam_addrs[b].phys)
            return tlbcam_addrs[b].start+(pa-tlbcam_addrs[b].phys);
    return 0;
}

/*
 * Set up a variable-size TLB entry (tlbcam). The parameters are not checked;
 * in particular size must be a power of 4 between 4k and the max supported by
 * an implementation; max may further be limited by what can be represented in
 * an unsigned long (for example, 32-bit implementations cannot support a 4GB
 * size).
 */
static void settlbcam(int index, unsigned long virt, phys_addr_t phys,
        unsigned long size, unsigned long flags, unsigned int pid)
{
    unsigned int tsize;

    tsize = __ilog2(size) - 10;

#ifdef CONFIG_SMP
    if ((flags & _PAGE_NO_CACHE) == 0)
        flags |= _PAGE_COHERENT;
#endif

    TLBCAM[index].MAS0 = MAS0_TLBSEL(1) | MAS0_ESEL(index) | MAS0_NV(index+1);
    TLBCAM[index].MAS1 = MAS1_VALID | MAS1_IPROT | MAS1_TSIZE(tsize) | MAS1_TID(pid);
    TLBCAM[index].MAS2 = virt & PAGE_MASK;

    TLBCAM[index].MAS2 |= (flags & _PAGE_WRITETHRU) ? MAS2_W : 0;
    TLBCAM[index].MAS2 |= (flags & _PAGE_NO_CACHE) ? MAS2_I : 0;
    TLBCAM[index].MAS2 |= (flags & _PAGE_COHERENT) ? MAS2_M : 0;
    TLBCAM[index].MAS2 |= (flags & _PAGE_GUARDED) ? MAS2_G : 0;
    TLBCAM[index].MAS2 |= (flags & _PAGE_ENDIAN) ? MAS2_E : 0;

    TLBCAM[index].MAS3 = (phys & MAS3_RPN) | MAS3_SX | MAS3_SR;
    TLBCAM[index].MAS3 |= ((flags & _PAGE_RW) ? MAS3_SW : 0);
    if (mmu_has_feature(MMU_FTR_BIG_PHYS))
        TLBCAM[index].MAS7 = (u64)phys >> 32;

    /* Below is unlikely -- only for large user pages or similar */
    if (pte_user(flags)) {
       TLBCAM[index].MAS3 |= MAS3_UX | MAS3_UR;
       TLBCAM[index].MAS3 |= ((flags & _PAGE_RW) ? MAS3_UW : 0);
    }

    tlbcam_addrs[index].start = virt;
    tlbcam_addrs[index].limit = virt + size - 1;
    tlbcam_addrs[index].phys = phys;

    loadcam_entry(index);
}

unsigned long calc_cam_sz(unsigned long ram, unsigned long virt,
              phys_addr_t phys)
{
    unsigned int camsize = __ilog2(ram);
    unsigned int align = __ffs(virt | phys);
    unsigned long max_cam;

    if ((mfspr(SPRN_MMUCFG) & MMUCFG_MAVN) == MMUCFG_MAVN_V1) {
        /* Convert (4^max) kB to (2^max) bytes */
        max_cam = ((mfspr(SPRN_TLB1CFG) >> 16) & 0xf) * 2 + 10;
        camsize &= ~1U;
        align &= ~1U;
    } else {
        /* Convert (2^max) kB to (2^max) bytes */
        max_cam = __ilog2(mfspr(SPRN_TLB1PS)) + 10;
    }

    if (camsize > align)
        camsize = align;
    if (camsize > max_cam)
        camsize = max_cam;

    return 1UL << camsize;
}

unsigned long map_mem_in_cams(unsigned long ram, int max_cam_idx)
{
    int i;
    unsigned long virt = PAGE_OFFSET;
    phys_addr_t phys = memstart_addr;
    unsigned long amount_mapped = 0;

    /* Calculate CAM values */
    for (i = 0; ram && i < max_cam_idx; i++) {
        unsigned long cam_sz;

        cam_sz = calc_cam_sz(ram, virt, phys);
        settlbcam(i, virt, phys, cam_sz, PAGE_KERNEL_X, 0);

        ram -= cam_sz;
        amount_mapped += cam_sz;
        virt += cam_sz;
        phys += cam_sz;
    }
    tlbcam_index = i;

    return amount_mapped;
}

#ifdef CONFIG_PPC32

#if defined(CONFIG_LOWMEM_CAM_NUM_BOOL) && (CONFIG_LOWMEM_CAM_NUM >= NUM_TLBCAMS)
#error "LOWMEM_CAM_NUM must be less than NUM_TLBCAMS"
#endif

unsigned long __init mmu_mapin_ram(unsigned long top)
{
    return tlbcam_addrs[tlbcam_index - 1].limit - PAGE_OFFSET + 1;
}

/*
 * MMU_init_hw does the chip-specific initialization of the MMU hardware.
 */
void __init MMU_init_hw(void)
{
    flush_instruction_cache();
}

void __init adjust_total_lowmem(void)
{
    unsigned long ram;
    int i;

    /* adjust lowmem size to __max_low_memory */
    ram = min((phys_addr_t)__max_low_memory, (phys_addr_t)total_lowmem);

    __max_low_memory = map_mem_in_cams(ram, CONFIG_LOWMEM_CAM_NUM);

    pr_info("Memory CAM mapping: ");
    for (i = 0; i < tlbcam_index - 1; i++)
        pr_cont("%lu/", tlbcam_sz(i) >> 20);
    pr_cont("%lu Mb, residual: %dMb\n", tlbcam_sz(tlbcam_index - 1) >> 20,
            (unsigned int)((total_lowmem - __max_low_memory) >> 20));

    memblock_set_current_limit(memstart_addr + __max_low_memory);
}

void setup_initial_memory_limit(phys_addr_t first_memblock_base,
                phys_addr_t first_memblock_size)
{
    phys_addr_t limit = first_memblock_base + first_memblock_size;

    /* 64M mapped initially according to head_fsl_booke.S */
    memblock_set_current_limit(min_t(u64, limit, 0x04000000));
}
#endif