LoongArch: Add misc common routines

Add some misc common routines for LoongArch, including: asm-offsets
routines, futex functions, i/o memory access functions, frame-buffer
functions, procfs information display, etc.

Reviewed-by: WANG Xuerui <git@xen0n.name>
Reviewed-by: Jiaxun Yang <jiaxun.yang@flygoat.com>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>

4 files changed, 264 insertions, 0 deletions

diff --git a/arch/loongarch/include/asm/asm-offsets.h b/arch/loongarch/include/asm/asm-offsets.h
new file mode 100644
index 000000000000..d9ad88d293e7
--- /dev/null
+++ b/arch/loongarch/include/asm/asm-offsets.h
@@ -0,0 +1,5 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (C) 2020-2022 Loongson Technology Corporation Limited
+ */
+#include <generated/asm-offsets.h>
diff --git a/arch/loongarch/include/asm/fb.h b/arch/loongarch/include/asm/fb.h
new file mode 100644
index 000000000000..3116bde8772d
--- /dev/null
+++ b/arch/loongarch/include/asm/fb.h
@@ -0,0 +1,23 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (C) 2020-2022 Loongson Technology Corporation Limited
+ */
+#ifndef _ASM_FB_H_
+#define _ASM_FB_H_
+
+#include <linux/fb.h>
+#include <linux/fs.h>
+#include <asm/page.h>
+
+static inline void fb_pgprotect(struct file *file, struct vm_area_struct *vma,
+				unsigned long off)
+{
+	vma->vm_page_prot = pgprot_writecombine(vma->vm_page_prot);
+}
+
+static inline int fb_is_primary_device(struct fb_info *info)
+{
+	return 0;
+}
+
+#endif /* _ASM_FB_H_ */
diff --git a/arch/loongarch/include/asm/futex.h b/arch/loongarch/include/asm/futex.h
new file mode 100644
index 000000000000..b27d55f92db7
--- /dev/null
+++ b/arch/loongarch/include/asm/futex.h
@@ -0,0 +1,107 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (C) 2020-2022 Loongson Technology Corporation Limited
+ */
+#ifndef _ASM_FUTEX_H
+#define _ASM_FUTEX_H
+
+#include <linux/futex.h>
+#include <linux/uaccess.h>
+#include <asm/barrier.h>
+#include <asm/compiler.h>
+#include <asm/errno.h>
+
+#define __futex_atomic_op(insn, ret, oldval, uaddr, oparg)		\
+{									\
+	__asm__ __volatile__(						\
+	"1:	ll.w	%1, %4 # __futex_atomic_op\n"		\
+	"	" insn	"				\n"	\
+	"2:	sc.w	$t0, %2				\n"	\
+	"	beq	$t0, $zero, 1b			\n"	\
+	"3:						\n"	\
+	"	.section .fixup,\"ax\"			\n"	\
+	"4:	li.w	%0, %6				\n"	\
+	"	b	3b				\n"	\
+	"	.previous				\n"	\
+	"	.section __ex_table,\"a\"		\n"	\
+	"	"__UA_ADDR "\t1b, 4b			\n"	\
+	"	"__UA_ADDR "\t2b, 4b			\n"	\
+	"	.previous				\n"	\
+	: "=r" (ret), "=&r" (oldval),				\
+	  "=ZC" (*uaddr)					\
+	: "0" (0), "ZC" (*uaddr), "Jr" (oparg),			\
+	  "i" (-EFAULT)						\
+	: "memory", "t0");					\
+}
+
+static inline int
+arch_futex_atomic_op_inuser(int op, int oparg, int *oval, u32 __user *uaddr)
+{
+	int oldval = 0, ret = 0;
+
+	pagefault_disable();
+
+	switch (op) {
+	case FUTEX_OP_SET:
+		__futex_atomic_op("move $t0, %z5", ret, oldval, uaddr, oparg);
+		break;
+	case FUTEX_OP_ADD:
+		__futex_atomic_op("add.w $t0, %1, %z5", ret, oldval, uaddr, oparg);
+		break;
+	case FUTEX_OP_OR:
+		__futex_atomic_op("or	$t0, %1, %z5", ret, oldval, uaddr, oparg);
+		break;
+	case FUTEX_OP_ANDN:
+		__futex_atomic_op("and	$t0, %1, %z5", ret, oldval, uaddr, ~oparg);
+		break;
+	case FUTEX_OP_XOR:
+		__futex_atomic_op("xor	$t0, %1, %z5", ret, oldval, uaddr, oparg);
+		break;
+	default:
+		ret = -ENOSYS;
+	}
+
+	pagefault_enable();
+
+	if (!ret)
+		*oval = oldval;
+
+	return ret;
+}
+
+static inline int
+futex_atomic_cmpxchg_inatomic(u32 *uval, u32 __user *uaddr, u32 oldval, u32 newval)
+{
+	int ret = 0;
+	u32 val = 0;
+
+	if (!access_ok(uaddr, sizeof(u32)))
+		return -EFAULT;
+
+	__asm__ __volatile__(
+	"# futex_atomic_cmpxchg_inatomic			\n"
+	"1:	ll.w	%1, %3					\n"
+	"	bne	%1, %z4, 3f				\n"
+	"	or	$t0, %z5, $zero				\n"
+	"2:	sc.w	$t0, %2					\n"
+	"	beq	$zero, $t0, 1b				\n"
+	"3:							\n"
+	"	.section .fixup,\"ax\"				\n"
+	"4:	li.d	%0, %6					\n"
+	"	b	3b					\n"
+	"	.previous					\n"
+	"	.section __ex_table,\"a\"			\n"
+	"	"__UA_ADDR "\t1b, 4b				\n"
+	"	"__UA_ADDR "\t2b, 4b				\n"
+	"	.previous					\n"
+	: "+r" (ret), "=&r" (val), "=" GCC_OFF_SMALL_ASM() (*uaddr)
+	: GCC_OFF_SMALL_ASM() (*uaddr), "Jr" (oldval), "Jr" (newval),
+	  "i" (-EFAULT)
+	: "memory", "t0");
+
+	*uval = val;
+
+	return ret;
+}
+
+#endif /* _ASM_FUTEX_H */
diff --git a/arch/loongarch/include/asm/io.h b/arch/loongarch/include/asm/io.h
new file mode 100644
index 000000000000..884599739b36
--- /dev/null
+++ b/arch/loongarch/include/asm/io.h
@@ -0,0 +1,129 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (C) 2020-2022 Loongson Technology Corporation Limited
+ */
+#ifndef _ASM_IO_H
+#define _ASM_IO_H
+
+#define ARCH_HAS_IOREMAP_WC
+
+#include <linux/compiler.h>
+#include <linux/kernel.h>
+#include <linux/types.h>
+
+#include <asm/addrspace.h>
+#include <asm/bug.h>
+#include <asm/byteorder.h>
+#include <asm/cpu.h>
+#include <asm/page.h>
+#include <asm/pgtable-bits.h>
+#include <asm/string.h>
+
+/*
+ * On LoongArch, I/O ports mappring is following:
+ *
+ *              |         ....          |
+ *              |-----------------------|
+ *              | pci io ports(64K~32M) |
+ *              |-----------------------|
+ *              | isa io ports(0  ~16K) |
+ * PCI_IOBASE ->|-----------------------|
+ *              |         ....          |
+ */
+#define PCI_IOBASE	((void __iomem *)(vm_map_base + (2 * PAGE_SIZE)))
+#define PCI_IOSIZE	SZ_32M
+#define ISA_IOSIZE	SZ_16K
+#define IO_SPACE_LIMIT	(PCI_IOSIZE - 1)
+
+/*
+ * Change "struct page" to physical address.
+ */
+#define page_to_phys(page)	((phys_addr_t)page_to_pfn(page) << PAGE_SHIFT)
+
+extern void __init __iomem *early_ioremap(u64 phys_addr, unsigned long size);
+extern void __init early_iounmap(void __iomem *addr, unsigned long size);
+
+#define early_memremap early_ioremap
+#define early_memunmap early_iounmap
+
+static inline void __iomem *ioremap_prot(phys_addr_t offset, unsigned long size,
+					 unsigned long prot_val)
+{
+	if (prot_val == _CACHE_CC)
+		return (void __iomem *)(unsigned long)(CACHE_BASE + offset);
+	else
+		return (void __iomem *)(unsigned long)(UNCACHE_BASE + 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.
+ */
+#define ioremap(offset, size)					\
+	ioremap_prot((offset), (size), _CACHE_SUC)
+
+/*
+ * ioremap_wc - map bus memory into CPU space
+ * @offset:     bus address of the memory
+ * @size:       size of the resource to map
+ *
+ * ioremap_wc 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.
+ *
+ * This version of ioremap ensures that the memory is marked uncachable
+ * but accelerated by means of write-combining feature. It is specifically
+ * useful for PCIe prefetchable windows, which may vastly improve a
+ * communications performance. If it was determined on boot stage, what
+ * CPU CCA doesn't support WUC, the method shall fall-back to the
+ * _CACHE_SUC option (see cpu_probe() method).
+ */
+#define ioremap_wc(offset, size)				\
+	ioremap_prot((offset), (size), _CACHE_WUC)
+
+/*
+ * ioremap_cache -  map bus memory into CPU space
+ * @offset:	    bus address of the memory
+ * @size:	    size of the resource to map
+ *
+ * ioremap_cache 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.
+ *
+ * This version of ioremap ensures that the memory is marked cachable by
+ * the CPU.  Also enables full write-combining.	 Useful for some
+ * memory-like regions on I/O busses.
+ */
+#define ioremap_cache(offset, size)				\
+	ioremap_prot((offset), (size), _CACHE_CC)
+
+static inline void iounmap(const volatile void __iomem *addr)
+{
+}
+
+#define mmiowb() asm volatile ("dbar 0" ::: "memory")
+
+/*
+ * String version of I/O memory access operations.
+ */
+extern void __memset_io(volatile void __iomem *dst, int c, size_t count);
+extern void __memcpy_toio(volatile void __iomem *to, const void *from, size_t count);
+extern void __memcpy_fromio(void *to, const volatile void __iomem *from, size_t count);
+#define memset_io(c, v, l)     __memset_io((c), (v), (l))
+#define memcpy_fromio(a, c, l) __memcpy_fromio((a), (c), (l))
+#define memcpy_toio(c, a, l)   __memcpy_toio((c), (a), (l))
+
+#include <asm-generic/io.h>
+
+#endif /* _ASM_IO_H */