summaryrefslogtreecommitdiff
path: root/arch/i386/mm/boot_ioremap.c
diff options
context:
space:
mode:
authorLinus Torvalds <torvalds@ppc970.osdl.org>2005-04-16 15:20:36 -0700
committerLinus Torvalds <torvalds@ppc970.osdl.org>2005-04-16 15:20:36 -0700
commit1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 (patch)
tree0bba044c4ce775e45a88a51686b5d9f90697ea9d /arch/i386/mm/boot_ioremap.c
downloadconfigs-1da177e4c3f41524e886b7f1b8a0c1fc7321cac2.tar.gz
Linux-2.6.12-rc2v2.6.12-rc2
Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
Diffstat (limited to 'arch/i386/mm/boot_ioremap.c')
-rw-r--r--arch/i386/mm/boot_ioremap.c97
1 files changed, 97 insertions, 0 deletions
diff --git a/arch/i386/mm/boot_ioremap.c b/arch/i386/mm/boot_ioremap.c
new file mode 100644
index 00000000000..523b30634e0
--- /dev/null
+++ b/arch/i386/mm/boot_ioremap.c
@@ -0,0 +1,97 @@
+/*
+ * arch/i386/mm/boot_ioremap.c
+ *
+ * Re-map functions for early boot-time before paging_init() when the
+ * boot-time pagetables are still in use
+ *
+ * Written by Dave Hansen <haveblue@us.ibm.com>
+ */
+
+
+/*
+ * We need to use the 2-level pagetable functions, but CONFIG_X86_PAE
+ * keeps that from happenning. If anyone has a better way, I'm listening.
+ *
+ * boot_pte_t is defined only if this all works correctly
+ */
+
+#include <linux/config.h>
+#undef CONFIG_X86_PAE
+#include <asm/page.h>
+#include <asm/pgtable.h>
+#include <asm/tlbflush.h>
+#include <linux/init.h>
+#include <linux/stddef.h>
+
+/*
+ * I'm cheating here. It is known that the two boot PTE pages are
+ * allocated next to each other. I'm pretending that they're just
+ * one big array.
+ */
+
+#define BOOT_PTE_PTRS (PTRS_PER_PTE*2)
+#define boot_pte_index(address) \
+ (((address) >> PAGE_SHIFT) & (BOOT_PTE_PTRS - 1))
+
+static inline boot_pte_t* boot_vaddr_to_pte(void *address)
+{
+ boot_pte_t* boot_pg = (boot_pte_t*)pg0;
+ return &boot_pg[boot_pte_index((unsigned long)address)];
+}
+
+/*
+ * This is only for a caller who is clever enough to page-align
+ * phys_addr and virtual_source, and who also has a preference
+ * about which virtual address from which to steal ptes
+ */
+static void __boot_ioremap(unsigned long phys_addr, unsigned long nrpages,
+ void* virtual_source)
+{
+ boot_pte_t* pte;
+ int i;
+ char *vaddr = virtual_source;
+
+ pte = boot_vaddr_to_pte(virtual_source);
+ for (i=0; i < nrpages; i++, phys_addr += PAGE_SIZE, pte++) {
+ set_pte(pte, pfn_pte(phys_addr>>PAGE_SHIFT, PAGE_KERNEL));
+ __flush_tlb_one(&vaddr[i*PAGE_SIZE]);
+ }
+}
+
+/* the virtual space we're going to remap comes from this array */
+#define BOOT_IOREMAP_PAGES 4
+#define BOOT_IOREMAP_SIZE (BOOT_IOREMAP_PAGES*PAGE_SIZE)
+static __initdata char boot_ioremap_space[BOOT_IOREMAP_SIZE]
+ __attribute__ ((aligned (PAGE_SIZE)));
+
+/*
+ * This only applies to things which need to ioremap before paging_init()
+ * bt_ioremap() and plain ioremap() are both useless at this point.
+ *
+ * When used, we're still using the boot-time pagetables, which only
+ * have 2 PTE pages mapping the first 8MB
+ *
+ * There is no unmap. The boot-time PTE pages aren't used after boot.
+ * If you really want the space back, just remap it yourself.
+ * boot_ioremap(&ioremap_space-PAGE_OFFSET, BOOT_IOREMAP_SIZE)
+ */
+__init void* boot_ioremap(unsigned long phys_addr, unsigned long size)
+{
+ unsigned long last_addr, offset;
+ unsigned int nrpages;
+
+ last_addr = phys_addr + size - 1;
+
+ /* page align the requested address */
+ offset = phys_addr & ~PAGE_MASK;
+ phys_addr &= PAGE_MASK;
+ size = PAGE_ALIGN(last_addr) - phys_addr;
+
+ nrpages = size >> PAGE_SHIFT;
+ if (nrpages > BOOT_IOREMAP_PAGES)
+ return NULL;
+
+ __boot_ioremap(phys_addr, nrpages, boot_ioremap_space);
+
+ return &boot_ioremap_space[offset];
+}