1 files changed, 298 insertions, 0 deletions
diff --git a/arch/m68k/mm/motorola.c b/arch/m68k/mm/motorola.c
new file mode 100644
index 000000000..2eb2b31fb
--- /dev/null
+++ b/arch/m68k/mm/motorola.c
@@ -0,0 +1,298 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * linux/arch/m68k/mm/motorola.c
+ *
+ * Routines specific to the Motorola MMU, originally from:
+ * linux/arch/m68k/init.c
+ * which are Copyright (C) 1995 Hamish Macdonald
+ *
+ * Moved 8/20/1999 Sam Creasey
+ */
+
+#include <linux/module.h>
+#include <linux/signal.h>
+#include <linux/sched.h>
+#include <linux/mm.h>
+#include <linux/swap.h>
+#include <linux/kernel.h>
+#include <linux/string.h>
+#include <linux/types.h>
+#include <linux/init.h>
+#include <linux/bootmem.h>
+#include <linux/memblock.h>
+#include <linux/gfp.h>
+
+#include <asm/setup.h>
+#include <linux/uaccess.h>
+#include <asm/page.h>
+#include <asm/pgalloc.h>
+#include <asm/machdep.h>
+#include <asm/io.h>
+#include <asm/dma.h>
+#ifdef CONFIG_ATARI
+#include <asm/atari_stram.h>
+#endif
+#include <asm/sections.h>
+
+#undef DEBUG
+
+#ifndef mm_cachebits
+/*
+ * Bits to add to page descriptors for "normal" caching mode.
+ * For 68020/030 this is 0.
+ * For 68040, this is _PAGE_CACHE040 (cachable, copyback)
+ */
+unsigned long mm_cachebits;
+EXPORT_SYMBOL(mm_cachebits);
+#endif
+
+/* size of memory already mapped in head.S */
+extern __initdata unsigned long m68k_init_mapped_size;
+
+extern unsigned long availmem;
+
+static pte_t * __init kernel_page_table(void)
+{
+	pte_t *ptablep;
+
+	ptablep = (pte_t *)alloc_bootmem_low_pages(PAGE_SIZE);
+
+	clear_page(ptablep);
+	__flush_page_to_ram(ptablep);
+	flush_tlb_kernel_page(ptablep);
+	nocache_page(ptablep);
+
+	return ptablep;
+}
+
+static pmd_t *last_pgtable __initdata = NULL;
+pmd_t *zero_pgtable __initdata = NULL;
+
+static pmd_t * __init kernel_ptr_table(void)
+{
+	if (!last_pgtable) {
+		unsigned long pmd, last;
+		int i;
+
+		/* Find the last ptr table that was used in head.S and
+		 * reuse the remaining space in that page for further
+		 * ptr tables.
+		 */
+		last = (unsigned long)kernel_pg_dir;
+		for (i = 0; i < PTRS_PER_PGD; i++) {
+			if (!pgd_present(kernel_pg_dir[i]))
+				continue;
+			pmd = __pgd_page(kernel_pg_dir[i]);
+			if (pmd > last)
+				last = pmd;
+		}
+
+		last_pgtable = (pmd_t *)last;
+#ifdef DEBUG
+		printk("kernel_ptr_init: %p\n", last_pgtable);
+#endif
+	}
+
+	last_pgtable += PTRS_PER_PMD;
+	if (((unsigned long)last_pgtable & ~PAGE_MASK) == 0) {
+		last_pgtable = (pmd_t *)alloc_bootmem_low_pages(PAGE_SIZE);
+
+		clear_page(last_pgtable);
+		__flush_page_to_ram(last_pgtable);
+		flush_tlb_kernel_page(last_pgtable);
+		nocache_page(last_pgtable);
+	}
+
+	return last_pgtable;
+}
+
+static void __init map_node(int node)
+{
+#define PTRTREESIZE (256*1024)
+#define ROOTTREESIZE (32*1024*1024)
+	unsigned long physaddr, virtaddr, size;
+	pgd_t *pgd_dir;
+	pmd_t *pmd_dir;
+	pte_t *pte_dir;
+
+	size = m68k_memory[node].size;
+	physaddr = m68k_memory[node].addr;
+	virtaddr = (unsigned long)phys_to_virt(physaddr);
+	physaddr |= m68k_supervisor_cachemode |
+		    _PAGE_PRESENT | _PAGE_ACCESSED | _PAGE_DIRTY;
+	if (CPU_IS_040_OR_060)
+		physaddr |= _PAGE_GLOBAL040;
+
+	while (size > 0) {
+#ifdef DEBUG
+		if (!(virtaddr & (PTRTREESIZE-1)))
+			printk ("\npa=%#lx va=%#lx ", physaddr & PAGE_MASK,
+				virtaddr);
+#endif
+		pgd_dir = pgd_offset_k(virtaddr);
+		if (virtaddr && CPU_IS_020_OR_030) {
+			if (!(virtaddr & (ROOTTREESIZE-1)) &&
+			    size >= ROOTTREESIZE) {
+#ifdef DEBUG
+				printk ("[very early term]");
+#endif
+				pgd_val(*pgd_dir) = physaddr;
+				size -= ROOTTREESIZE;
+				virtaddr += ROOTTREESIZE;
+				physaddr += ROOTTREESIZE;
+				continue;
+			}
+		}
+		if (!pgd_present(*pgd_dir)) {
+			pmd_dir = kernel_ptr_table();
+#ifdef DEBUG
+			printk ("[new pointer %p]", pmd_dir);
+#endif
+			pgd_set(pgd_dir, pmd_dir);
+		} else
+			pmd_dir = pmd_offset(pgd_dir, virtaddr);
+
+		if (CPU_IS_020_OR_030) {
+			if (virtaddr) {
+#ifdef DEBUG
+				printk ("[early term]");
+#endif
+				pmd_dir->pmd[(virtaddr/PTRTREESIZE) & 15] = physaddr;
+				physaddr += PTRTREESIZE;
+			} else {
+				int i;
+#ifdef DEBUG
+				printk ("[zero map]");
+#endif
+				zero_pgtable = kernel_ptr_table();
+				pte_dir = (pte_t *)zero_pgtable;
+				pmd_dir->pmd[0] = virt_to_phys(pte_dir) |
+					_PAGE_TABLE | _PAGE_ACCESSED;
+				pte_val(*pte_dir++) = 0;
+				physaddr += PAGE_SIZE;
+				for (i = 1; i < 64; physaddr += PAGE_SIZE, i++)
+					pte_val(*pte_dir++) = physaddr;
+			}
+			size -= PTRTREESIZE;
+			virtaddr += PTRTREESIZE;
+		} else {
+			if (!pmd_present(*pmd_dir)) {
+#ifdef DEBUG
+				printk ("[new table]");
+#endif
+				pte_dir = kernel_page_table();
+				pmd_set(pmd_dir, pte_dir);
+			}
+			pte_dir = pte_offset_kernel(pmd_dir, virtaddr);
+
+			if (virtaddr) {
+				if (!pte_present(*pte_dir))
+					pte_val(*pte_dir) = physaddr;
+			} else
+				pte_val(*pte_dir) = 0;
+			size -= PAGE_SIZE;
+			virtaddr += PAGE_SIZE;
+			physaddr += PAGE_SIZE;
+		}
+
+	}
+#ifdef DEBUG
+	printk("\n");
+#endif
+}
+
+/*
+ * paging_init() continues the virtual memory environment setup which
+ * was begun by the code in arch/head.S.
+ */
+void __init paging_init(void)
+{
+	unsigned long zones_size[MAX_NR_ZONES] = { 0, };
+	unsigned long min_addr, max_addr;
+	unsigned long addr;
+	int i;
+
+#ifdef DEBUG
+	printk ("start of paging_init (%p, %lx)\n", kernel_pg_dir, availmem);
+#endif
+
+	/* Fix the cache mode in the page descriptors for the 680[46]0.  */
+	if (CPU_IS_040_OR_060) {
+		int i;
+#ifndef mm_cachebits
+		mm_cachebits = _PAGE_CACHE040;
+#endif
+		for (i = 0; i < 16; i++)
+			pgprot_val(protection_map[i]) |= _PAGE_CACHE040;
+	}
+
+	min_addr = m68k_memory[0].addr;
+	max_addr = min_addr + m68k_memory[0].size;
+	memblock_add(m68k_memory[0].addr, m68k_memory[0].size);
+	for (i = 1; i < m68k_num_memory;) {
+		if (m68k_memory[i].addr < min_addr) {
+			printk("Ignoring memory chunk at 0x%lx:0x%lx before the first chunk\n",
+				m68k_memory[i].addr, m68k_memory[i].size);
+			printk("Fix your bootloader or use a memfile to make use of this area!\n");
+			m68k_num_memory--;
+			memmove(m68k_memory + i, m68k_memory + i + 1,
+				(m68k_num_memory - i) * sizeof(struct m68k_mem_info));
+			continue;
+		}
+		memblock_add(m68k_memory[i].addr, m68k_memory[i].size);
+		addr = m68k_memory[i].addr + m68k_memory[i].size;
+		if (addr > max_addr)
+			max_addr = addr;
+		i++;
+	}
+	m68k_memoffset = min_addr - PAGE_OFFSET;
+	m68k_virt_to_node_shift = fls(max_addr - min_addr - 1) - 6;
+
+	module_fixup(NULL, __start_fixup, __stop_fixup);
+	flush_icache();
+
+	high_memory = phys_to_virt(max_addr);
+
+	min_low_pfn = availmem >> PAGE_SHIFT;
+	max_pfn = max_low_pfn = max_addr >> PAGE_SHIFT;
+
+	/* Reserve kernel text/data/bss and the memory allocated in head.S */
+	memblock_reserve(m68k_memory[0].addr, availmem - m68k_memory[0].addr);
+
+	/*
+	 * Map the physical memory available into the kernel virtual
+	 * address space. Make sure memblock will not try to allocate
+	 * pages beyond the memory we already mapped in head.S
+	 */
+	memblock_set_bottom_up(true);
+
+	for (i = 0; i < m68k_num_memory; i++) {
+		m68k_setup_node(i);
+		map_node(i);
+	}
+
+	flush_tlb_all();
+
+	/*
+	 * initialize the bad page table and bad page to point
+	 * to a couple of allocated pages
+	 */
+	empty_zero_page = alloc_bootmem_pages(PAGE_SIZE);
+
+	/*
+	 * Set up SFC/DFC registers
+	 */
+	set_fs(KERNEL_DS);
+
+#ifdef DEBUG
+	printk ("before free_area_init\n");
+#endif
+	for (i = 0; i < m68k_num_memory; i++) {
+		zones_size[ZONE_DMA] = m68k_memory[i].size >> PAGE_SHIFT;
+		free_area_init_node(i, zones_size,
+				    m68k_memory[i].addr >> PAGE_SHIFT, NULL);
+		if (node_present_pages(i))
+			node_set_state(i, N_NORMAL_MEMORY);
+	}
+}
+