sh: Provide the kmap_coherent() interface generically.

This plugs in kmap_coherent() for the non-SH4 cases to permit the
pg-mmu.c bits to be used generically across all CPUs. SH-5 is still in
the TODO state, but will move over to fixmap and the generic interface
gradually.

Signed-off-by: Paul Mundt <lethal@linux-sh.org>

1 files changed, 64 insertions, 0 deletions

diff --git a/arch/sh/mm/kmap.c b/arch/sh/mm/kmap.c
new file mode 100644
index 000000000000..3eecf0d42f1a
--- /dev/null
+++ b/arch/sh/mm/kmap.c
@@ -0,0 +1,64 @@
+/*
+ * arch/sh/mm/kmap.c
+ *
+ * Copyright (C) 1999, 2000, 2002  Niibe Yutaka
+ * Copyright (C) 2002 - 2009  Paul Mundt
+ *
+ * Released under the terms of the GNU GPL v2.0.
+ */
+#include <linux/mm.h>
+#include <linux/init.h>
+#include <linux/mutex.h>
+#include <linux/fs.h>
+#include <linux/highmem.h>
+#include <linux/module.h>
+#include <asm/mmu_context.h>
+#include <asm/cacheflush.h>
+
+#define kmap_get_fixmap_pte(vaddr)                                     \
+	pte_offset_kernel(pmd_offset(pud_offset(pgd_offset_k(vaddr), (vaddr)), (vaddr)), (vaddr))
+
+static pte_t *kmap_coherent_pte;
+
+void __init kmap_coherent_init(void)
+{
+	unsigned long vaddr;
+
+	if (!boot_cpu_data.dcache.n_aliases)
+		return;
+
+	/* cache the first coherent kmap pte */
+	vaddr = __fix_to_virt(FIX_CMAP_BEGIN);
+	kmap_coherent_pte = kmap_get_fixmap_pte(vaddr);
+}
+
+void *kmap_coherent(struct page *page, unsigned long addr)
+{
+	enum fixed_addresses idx;
+	unsigned long vaddr, flags;
+	pte_t pte;
+
+	BUG_ON(test_bit(PG_dcache_dirty, &page->flags));
+
+	inc_preempt_count();
+
+	idx = (addr & current_cpu_data.dcache.alias_mask) >> PAGE_SHIFT;
+	vaddr = __fix_to_virt(FIX_CMAP_END - idx);
+	pte = mk_pte(page, PAGE_KERNEL);
+
+	local_irq_save(flags);
+	flush_tlb_one(get_asid(), vaddr);
+	local_irq_restore(flags);
+
+	update_mmu_cache(NULL, vaddr, pte);
+
+	set_pte(kmap_coherent_pte - (FIX_CMAP_END - idx), pte);
+
+	return (void *)vaddr;
+}
+
+void kunmap_coherent(void)
+{
+	dec_preempt_count();
+	preempt_check_resched();
+}