C6X: memory management and DMA support

Original port to early 2.6 kernel using TI COFF toolchain.
Brought up to date by Mark Salter <msalter@redhat.com>

The C6X architecture currently lacks an MMU so memory management is relatively
simple. There is no bus snooping between L2 and main memory but coherent DMA
memory is supported by making regions of main memory uncached. If such a region
is desired, it can be specified on the commandline with a "memdma=" argument.

Signed-off-by: Aurelien Jacquiot <a-jacquiot@ti.com>
Signed-off-by: Mark Salter <msalter@redhat.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>

1 files changed, 113 insertions, 0 deletions

diff --git a/arch/c6x/mm/init.c b/arch/c6x/mm/init.c
new file mode 100644
index 000000000000..89395f09648a
--- /dev/null
+++ b/arch/c6x/mm/init.c
@@ -0,0 +1,113 @@
+/*
+ *  Port on Texas Instruments TMS320C6x architecture
+ *
+ *  Copyright (C) 2004, 2009, 2010, 2011 Texas Instruments Incorporated
+ *  Author: Aurelien Jacquiot (aurelien.jacquiot@jaluna.com)
+ *
+ *  This program is free software; you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License version 2 as
+ *  published by the Free Software Foundation.
+ */
+#include <linux/mm.h>
+#include <linux/swap.h>
+#include <linux/module.h>
+#include <linux/bootmem.h>
+#ifdef CONFIG_BLK_DEV_RAM
+#include <linux/blkdev.h>
+#endif
+#include <linux/initrd.h>
+
+#include <asm/sections.h>
+
+/*
+ * ZERO_PAGE is a special page that is used for zero-initialized
+ * data and COW.
+ */
+unsigned long empty_zero_page;
+EXPORT_SYMBOL(empty_zero_page);
+
+/*
+ * paging_init() continues the virtual memory environment setup which
+ * was begun by the code in arch/head.S.
+ * The parameters are pointers to where to stick the starting and ending
+ * addresses  of available kernel virtual memory.
+ */
+void __init paging_init(void)
+{
+        struct pglist_data *pgdat = NODE_DATA(0);
+        unsigned long zones_size[MAX_NR_ZONES] = {0, };
+
+        empty_zero_page      = (unsigned long) alloc_bootmem_pages(PAGE_SIZE);
+        memset((void *)empty_zero_page, 0, PAGE_SIZE);
+
+        /*
+         * Set up user data space
+         */
+        set_fs(KERNEL_DS);
+
+        /*
+         * Define zones
+         */
+        zones_size[ZONE_NORMAL] = (memory_end - PAGE_OFFSET) >> PAGE_SHIFT;
+        pgdat->node_zones[ZONE_NORMAL].zone_start_pfn =
+                __pa(PAGE_OFFSET) >> PAGE_SHIFT;
+
+        free_area_init(zones_size);
+}
+
+void __init mem_init(void)
+{
+        int codek, datak;
+        unsigned long tmp;
+        unsigned long len = memory_end - memory_start;
+
+        high_memory = (void *)(memory_end & PAGE_MASK);
+
+        /* this will put all memory onto the freelists */
+        totalram_pages = free_all_bootmem();
+
+        codek = (_etext - _stext) >> 10;
+        datak = (_end - _sdata) >> 10;
+
+        tmp = nr_free_pages() << PAGE_SHIFT;
+        printk(KERN_INFO "Memory: %luk/%luk RAM (%dk kernel code, %dk data)\n",
+               tmp >> 10, len >> 10, codek, datak);
+}
+
+#ifdef CONFIG_BLK_DEV_INITRD
+void __init free_initrd_mem(unsigned long start, unsigned long end)
+{
+        int pages = 0;
+        for (; start < end; start += PAGE_SIZE) {
+                ClearPageReserved(virt_to_page(start));
+                init_page_count(virt_to_page(start));
+                free_page(start);
+                totalram_pages++;
+                pages++;
+        }
+        printk(KERN_INFO "Freeing initrd memory: %luk freed\n",
+               (pages * PAGE_SIZE) >> 10);
+}
+#endif
+
+void __init free_initmem(void)
+{
+        unsigned long addr;
+
+        /*
+         * The following code should be cool even if these sections
+         * are not page aligned.
+         */
+        addr = PAGE_ALIGN((unsigned long)(__init_begin));
+
+        /* next to check that the page we free is not a partial page */
+        for (; addr + PAGE_SIZE < (unsigned long)(__init_end);
+             addr += PAGE_SIZE) {
+                ClearPageReserved(virt_to_page(addr));
+                init_page_count(virt_to_page(addr));
+                free_page(addr);
+                totalram_pages++;
+        }
+        printk(KERN_INFO "Freeing unused kernel memory: %dK freed\n",
+               (int) ((addr - PAGE_ALIGN((long) &__init_begin)) >> 10));
+}