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authorPalmer Dabbelt <palmer@dabbelt.com>2017-07-10 18:05:09 -0700
committerPalmer Dabbelt <palmer@dabbelt.com>2017-09-26 15:26:47 -0700
commit6d60b6ee0c9777b92c47f6dc8aad1dd90612e4fa (patch)
tree759b45dbcebd1700f2f9df4deb0513ba54da36c7 /arch/riscv/mm
parent7db91e57a0acde126a162ababfb1e0ab190130cb (diff)
RISC-V: Device, timer, IRQs, and the SBI
This patch contains code that interfaces with devices that are mandated by the RISC-V supervisor specification and that don't have explicit drivers anywhere else in the tree. This includes the staticly defined interrupts, the CSR-mapped timer, and virtualized SBI devices. Signed-off-by: Palmer Dabbelt <palmer@dabbelt.com>
Diffstat (limited to 'arch/riscv/mm')
-rw-r--r--arch/riscv/mm/ioremap.c92
1 files changed, 92 insertions, 0 deletions
diff --git a/arch/riscv/mm/ioremap.c b/arch/riscv/mm/ioremap.c
new file mode 100644
index 000000000000..e99194a4077e
--- /dev/null
+++ b/arch/riscv/mm/ioremap.c
@@ -0,0 +1,92 @@
+/*
+ * (C) Copyright 1995 1996 Linus Torvalds
+ * (C) Copyright 2012 Regents of the University of California
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, version 2.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ */
+
+#include <linux/export.h>
+#include <linux/mm.h>
+#include <linux/vmalloc.h>
+#include <linux/io.h>
+
+#include <asm/pgtable.h>
+
+/*
+ * Remap an arbitrary physical address space into the kernel virtual
+ * address space. Needed when the kernel wants to access high addresses
+ * directly.
+ *
+ * NOTE! We need to allow non-page-aligned mappings too: we will obviously
+ * have to convert them into an offset in a page-aligned mapping, but the
+ * caller shouldn't need to know that small detail.
+ */
+static void __iomem *__ioremap_caller(phys_addr_t addr, size_t size,
+ pgprot_t prot, void *caller)
+{
+ phys_addr_t last_addr;
+ unsigned long offset, vaddr;
+ struct vm_struct *area;
+
+ /* Disallow wrap-around or zero size */
+ last_addr = addr + size - 1;
+ if (!size || last_addr < addr)
+ return NULL;
+
+ /* Page-align mappings */
+ offset = addr & (~PAGE_MASK);
+ addr &= PAGE_MASK;
+ size = PAGE_ALIGN(size + offset);
+
+ area = get_vm_area_caller(size, VM_IOREMAP, caller);
+ if (!area)
+ return NULL;
+ vaddr = (unsigned long)area->addr;
+
+ if (ioremap_page_range(vaddr, vaddr + size, addr, prot)) {
+ free_vm_area(area);
+ return NULL;
+ }
+
+ return (void __iomem *)(vaddr + offset);
+}
+
+/*
+ * ioremap - map bus memory into CPU space
+ * @offset: bus address of the memory
+ * @size: size of the resource to map
+ *
+ * ioremap performs a platform specific sequence of operations to
+ * make bus memory CPU accessible via the readb/readw/readl/writeb/
+ * writew/writel functions and the other mmio helpers. The returned
+ * address is not guaranteed to be usable directly as a virtual
+ * address.
+ *
+ * Must be freed with iounmap.
+ */
+void __iomem *ioremap(phys_addr_t offset, unsigned long size)
+{
+ return __ioremap_caller(offset, size, PAGE_KERNEL,
+ __builtin_return_address(0));
+}
+EXPORT_SYMBOL(ioremap);
+
+
+/**
+ * iounmap - Free a IO remapping
+ * @addr: virtual address from ioremap_*
+ *
+ * Caller must ensure there is only one unmapping for the same pointer.
+ */
+void iounmap(void __iomem *addr)
+{
+ vunmap((void *)((unsigned long)addr & PAGE_MASK));
+}
+EXPORT_SYMBOL(iounmap);