1 files changed, 303 insertions, 0 deletions
diff --git a/mm/early_ioremap.c b/mm/early_ioremap.c
new file mode 100644
index 000000000..a0018ad1a
--- /dev/null
+++ b/mm/early_ioremap.c
@@ -0,0 +1,303 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Provide common bits of early_ioremap() support for architectures needing
+ * temporary mappings during boot before ioremap() is available.
+ *
+ * This is mostly a direct copy of the x86 early_ioremap implementation.
+ *
+ * (C) Copyright 1995 1996, 2014 Linus Torvalds
+ *
+ */
+#include <linux/kernel.h>
+#include <linux/init.h>
+#include <linux/io.h>
+#include <linux/module.h>
+#include <linux/slab.h>
+#include <linux/mm.h>
+#include <linux/vmalloc.h>
+#include <asm/fixmap.h>
+#include <asm/early_ioremap.h>
+
+#ifdef CONFIG_MMU
+static int early_ioremap_debug __initdata;
+
+static int __init early_ioremap_debug_setup(char *str)
+{
+	early_ioremap_debug = 1;
+
+	return 0;
+}
+early_param("early_ioremap_debug", early_ioremap_debug_setup);
+
+static int after_paging_init __initdata;
+
+pgprot_t __init __weak early_memremap_pgprot_adjust(resource_size_t phys_addr,
+						    unsigned long size,
+						    pgprot_t prot)
+{
+	return prot;
+}
+
+void __init __weak early_ioremap_shutdown(void)
+{
+}
+
+void __init early_ioremap_reset(void)
+{
+	early_ioremap_shutdown();
+	after_paging_init = 1;
+}
+
+/*
+ * Generally, ioremap() is available after paging_init() has been called.
+ * Architectures wanting to allow early_ioremap after paging_init() can
+ * define __late_set_fixmap and __late_clear_fixmap to do the right thing.
+ */
+#ifndef __late_set_fixmap
+static inline void __init __late_set_fixmap(enum fixed_addresses idx,
+					    phys_addr_t phys, pgprot_t prot)
+{
+	BUG();
+}
+#endif
+
+#ifndef __late_clear_fixmap
+static inline void __init __late_clear_fixmap(enum fixed_addresses idx)
+{
+	BUG();
+}
+#endif
+
+static void __iomem *prev_map[FIX_BTMAPS_SLOTS] __initdata;
+static unsigned long prev_size[FIX_BTMAPS_SLOTS] __initdata;
+static unsigned long slot_virt[FIX_BTMAPS_SLOTS] __initdata;
+
+void __init early_ioremap_setup(void)
+{
+	int i;
+
+	for (i = 0; i < FIX_BTMAPS_SLOTS; i++)
+		if (WARN_ON(prev_map[i]))
+			break;
+
+	for (i = 0; i < FIX_BTMAPS_SLOTS; i++)
+		slot_virt[i] = __fix_to_virt(FIX_BTMAP_BEGIN - NR_FIX_BTMAPS*i);
+}
+
+static int __init check_early_ioremap_leak(void)
+{
+	int count = 0;
+	int i;
+
+	for (i = 0; i < FIX_BTMAPS_SLOTS; i++)
+		if (prev_map[i])
+			count++;
+
+	if (WARN(count, KERN_WARNING
+		 "Debug warning: early ioremap leak of %d areas detected.\n"
+		 "please boot with early_ioremap_debug and report the dmesg.\n",
+		 count))
+		return 1;
+	return 0;
+}
+late_initcall(check_early_ioremap_leak);
+
+static void __init __iomem *
+__early_ioremap(resource_size_t phys_addr, unsigned long size, pgprot_t prot)
+{
+	unsigned long offset;
+	resource_size_t last_addr;
+	unsigned int nrpages;
+	enum fixed_addresses idx;
+	int i, slot;
+
+	WARN_ON(system_state >= SYSTEM_RUNNING);
+
+	slot = -1;
+	for (i = 0; i < FIX_BTMAPS_SLOTS; i++) {
+		if (!prev_map[i]) {
+			slot = i;
+			break;
+		}
+	}
+
+	if (WARN(slot < 0, "%s(%pa, %08lx) not found slot\n",
+		 __func__, &phys_addr, size))
+		return NULL;
+
+	/* Don't allow wraparound or zero size */
+	last_addr = phys_addr + size - 1;
+	if (WARN_ON(!size || last_addr < phys_addr))
+		return NULL;
+
+	prev_size[slot] = size;
+	/*
+	 * Mappings have to be page-aligned
+	 */
+	offset = offset_in_page(phys_addr);
+	phys_addr &= PAGE_MASK;
+	size = PAGE_ALIGN(last_addr + 1) - phys_addr;
+
+	/*
+	 * Mappings have to fit in the FIX_BTMAP area.
+	 */
+	nrpages = size >> PAGE_SHIFT;
+	if (WARN_ON(nrpages > NR_FIX_BTMAPS))
+		return NULL;
+
+	/*
+	 * Ok, go for it..
+	 */
+	idx = FIX_BTMAP_BEGIN - NR_FIX_BTMAPS*slot;
+	while (nrpages > 0) {
+		if (after_paging_init)
+			__late_set_fixmap(idx, phys_addr, prot);
+		else
+			__early_set_fixmap(idx, phys_addr, prot);
+		phys_addr += PAGE_SIZE;
+		--idx;
+		--nrpages;
+	}
+	WARN(early_ioremap_debug, "%s(%pa, %08lx) [%d] => %08lx + %08lx\n",
+	     __func__, &phys_addr, size, slot, offset, slot_virt[slot]);
+
+	prev_map[slot] = (void __iomem *)(offset + slot_virt[slot]);
+	return prev_map[slot];
+}
+
+void __init early_iounmap(void __iomem *addr, unsigned long size)
+{
+	unsigned long virt_addr;
+	unsigned long offset;
+	unsigned int nrpages;
+	enum fixed_addresses idx;
+	int i, slot;
+
+	slot = -1;
+	for (i = 0; i < FIX_BTMAPS_SLOTS; i++) {
+		if (prev_map[i] == addr) {
+			slot = i;
+			break;
+		}
+	}
+
+	if (WARN(slot < 0, "early_iounmap(%p, %08lx) not found slot\n",
+		 addr, size))
+		return;
+
+	if (WARN(prev_size[slot] != size,
+		 "early_iounmap(%p, %08lx) [%d] size not consistent %08lx\n",
+		 addr, size, slot, prev_size[slot]))
+		return;
+
+	WARN(early_ioremap_debug, "early_iounmap(%p, %08lx) [%d]\n",
+	     addr, size, slot);
+
+	virt_addr = (unsigned long)addr;
+	if (WARN_ON(virt_addr < fix_to_virt(FIX_BTMAP_BEGIN)))
+		return;
+
+	offset = offset_in_page(virt_addr);
+	nrpages = PAGE_ALIGN(offset + size) >> PAGE_SHIFT;
+
+	idx = FIX_BTMAP_BEGIN - NR_FIX_BTMAPS*slot;
+	while (nrpages > 0) {
+		if (after_paging_init)
+			__late_clear_fixmap(idx);
+		else
+			__early_set_fixmap(idx, 0, FIXMAP_PAGE_CLEAR);
+		--idx;
+		--nrpages;
+	}
+	prev_map[slot] = NULL;
+}
+
+/* Remap an IO device */
+void __init __iomem *
+early_ioremap(resource_size_t phys_addr, unsigned long size)
+{
+	return __early_ioremap(phys_addr, size, FIXMAP_PAGE_IO);
+}
+
+/* Remap memory */
+void __init *
+early_memremap(resource_size_t phys_addr, unsigned long size)
+{
+	pgprot_t prot = early_memremap_pgprot_adjust(phys_addr, size,
+						     FIXMAP_PAGE_NORMAL);
+
+	return (__force void *)__early_ioremap(phys_addr, size, prot);
+}
+#ifdef FIXMAP_PAGE_RO
+void __init *
+early_memremap_ro(resource_size_t phys_addr, unsigned long size)
+{
+	pgprot_t prot = early_memremap_pgprot_adjust(phys_addr, size,
+						     FIXMAP_PAGE_RO);
+
+	return (__force void *)__early_ioremap(phys_addr, size, prot);
+}
+#endif
+
+#ifdef CONFIG_ARCH_USE_MEMREMAP_PROT
+void __init *
+early_memremap_prot(resource_size_t phys_addr, unsigned long size,
+		    unsigned long prot_val)
+{
+	return (__force void *)__early_ioremap(phys_addr, size,
+					       __pgprot(prot_val));
+}
+#endif
+
+#define MAX_MAP_CHUNK	(NR_FIX_BTMAPS << PAGE_SHIFT)
+
+void __init copy_from_early_mem(void *dest, phys_addr_t src, unsigned long size)
+{
+	unsigned long slop, clen;
+	char *p;
+
+	while (size) {
+		slop = offset_in_page(src);
+		clen = size;
+		if (clen > MAX_MAP_CHUNK - slop)
+			clen = MAX_MAP_CHUNK - slop;
+		p = early_memremap(src & PAGE_MASK, clen + slop);
+		memcpy(dest, p + slop, clen);
+		early_memunmap(p, clen + slop);
+		dest += clen;
+		src += clen;
+		size -= clen;
+	}
+}
+
+#else /* CONFIG_MMU */
+
+void __init __iomem *
+early_ioremap(resource_size_t phys_addr, unsigned long size)
+{
+	return (__force void __iomem *)phys_addr;
+}
+
+/* Remap memory */
+void __init *
+early_memremap(resource_size_t phys_addr, unsigned long size)
+{
+	return (void *)phys_addr;
+}
+void __init *
+early_memremap_ro(resource_size_t phys_addr, unsigned long size)
+{
+	return (void *)phys_addr;
+}
+
+void __init early_iounmap(void __iomem *addr, unsigned long size)
+{
+}
+
+#endif /* CONFIG_MMU */
+
+
+void __init early_memunmap(void *addr, unsigned long size)
+{
+	early_iounmap((__force void __iomem *)addr, size);
+}