1 files changed, 109 insertions, 0 deletions
diff --git a/arch/csky/mm/highmem.c b/arch/csky/mm/highmem.c
new file mode 100644
index 000000000..89c10800a
--- /dev/null
+++ b/arch/csky/mm/highmem.c
@@ -0,0 +1,109 @@
+// SPDX-License-Identifier: GPL-2.0
+// Copyright (C) 2018 Hangzhou C-SKY Microsystems co.,ltd.
+
+#include <linux/module.h>
+#include <linux/highmem.h>
+#include <linux/smp.h>
+#include <linux/memblock.h>
+#include <asm/fixmap.h>
+#include <asm/tlbflush.h>
+#include <asm/cacheflush.h>
+
+static pte_t *kmap_pte;
+
+unsigned long highstart_pfn, highend_pfn;
+
+void kmap_flush_tlb(unsigned long addr)
+{
+	flush_tlb_one(addr);
+}
+EXPORT_SYMBOL(kmap_flush_tlb);
+
+void *kmap_atomic_high_prot(struct page *page, pgprot_t prot)
+{
+	unsigned long vaddr;
+	int idx, type;
+
+	type = kmap_atomic_idx_push();
+	idx = type + KM_TYPE_NR*smp_processor_id();
+	vaddr = __fix_to_virt(FIX_KMAP_BEGIN + idx);
+#ifdef CONFIG_DEBUG_HIGHMEM
+	BUG_ON(!pte_none(*(kmap_pte - idx)));
+#endif
+	set_pte(kmap_pte-idx, mk_pte(page, prot));
+	flush_tlb_one((unsigned long)vaddr);
+
+	return (void *)vaddr;
+}
+EXPORT_SYMBOL(kmap_atomic_high_prot);
+
+void kunmap_atomic_high(void *kvaddr)
+{
+	unsigned long vaddr = (unsigned long) kvaddr & PAGE_MASK;
+	int idx;
+
+	if (vaddr < FIXADDR_START)
+		return;
+
+#ifdef CONFIG_DEBUG_HIGHMEM
+	idx = KM_TYPE_NR*smp_processor_id() + kmap_atomic_idx();
+
+	BUG_ON(vaddr != __fix_to_virt(FIX_KMAP_BEGIN + idx));
+
+	pte_clear(&init_mm, vaddr, kmap_pte - idx);
+	flush_tlb_one(vaddr);
+#else
+	(void) idx; /* to kill a warning */
+#endif
+	kmap_atomic_idx_pop();
+}
+EXPORT_SYMBOL(kunmap_atomic_high);
+
+/*
+ * This is the same as kmap_atomic() but can map memory that doesn't
+ * have a struct page associated with it.
+ */
+void *kmap_atomic_pfn(unsigned long pfn)
+{
+	unsigned long vaddr;
+	int idx, type;
+
+	pagefault_disable();
+
+	type = kmap_atomic_idx_push();
+	idx = type + KM_TYPE_NR*smp_processor_id();
+	vaddr = __fix_to_virt(FIX_KMAP_BEGIN + idx);
+	set_pte(kmap_pte-idx, pfn_pte(pfn, PAGE_KERNEL));
+	flush_tlb_one(vaddr);
+
+	return (void *) vaddr;
+}
+
+static void __init kmap_pages_init(void)
+{
+	unsigned long vaddr;
+	pgd_t *pgd;
+	pmd_t *pmd;
+	pud_t *pud;
+	pte_t *pte;
+
+	vaddr = PKMAP_BASE;
+	fixrange_init(vaddr, vaddr + PAGE_SIZE*LAST_PKMAP, swapper_pg_dir);
+
+	pgd = swapper_pg_dir + pgd_index(vaddr);
+	pud = (pud_t *)pgd;
+	pmd = pmd_offset(pud, vaddr);
+	pte = pte_offset_kernel(pmd, vaddr);
+	pkmap_page_table = pte;
+}
+
+void __init kmap_init(void)
+{
+	unsigned long vaddr;
+
+	kmap_pages_init();
+
+	vaddr = __fix_to_virt(FIX_KMAP_BEGIN);
+
+	kmap_pte = pte_offset_kernel((pmd_t *)pgd_offset_k(vaddr), vaddr);
+}