MIPS: Use GENERIC_IOMAP

MIPS has a copy of lib/iomap.c with minor alterations, none of which are
necessary given appropriate definitions of PIO_OFFSET, PIO_MASK &
PIO_RESERVED. Provide such definitions, select GENERIC_IOMAP & remove
arch/mips/lib/iomap.c to cut back on the needless duplication.

The one change this does make is to our mmio_{in,out}s[bwl] functions,
which began to deviate from their generic counterparts with commit
0845bb721ebb ("MIPS: iomap: Use __mem_{read,write}{b,w,l} for MMIO"). I
suspect that this commit was incorrect, and that the SEAD-3 platform
should have instead selected CONFIG_SWAP_IO_SPACE. Since the SEAD-3
platform code is now gone & the board is instead supported by the
generic platform (CONFIG_MIPS_GENERIC) which selects
CONFIG_SWAP_IO_SPACE anyway, this shouldn't be a problem any more.

Signed-off-by: Paul Burton <paul.burton@mips.com>
Patchwork: https://patchwork.linux-mips.org/patch/20342/
Cc: linux-mips@linux-mips.org

arch/mips/Kconfig

@@ -21,6 +21,7 @@ config MIPS
 	select GENERIC_CLOCKEVENTS
 	select GENERIC_CMOS_UPDATE
 	select GENERIC_CPU_AUTOPROBE
+	select GENERIC_IOMAP
 	select GENERIC_IRQ_PROBE
 	select GENERIC_IRQ_SHOW
 	select GENERIC_LIB_ASHLDI3
@@ -28,7 +29,6 @@ config MIPS
 	select GENERIC_LIB_CMPDI2
 	select GENERIC_LIB_LSHRDI3
 	select GENERIC_LIB_UCMPDI2
-	select GENERIC_PCI_IOMAP
 	select GENERIC_SCHED_CLOCK if !CAVIUM_OCTEON_SOC
 	select GENERIC_SMP_IDLE_THREAD
 	select GENERIC_TIME_VSYSCALL

arch/mips/include/asm/io.h

@@ -79,6 +79,16 @@ static inline void set_io_port_base(unsigned long base)
 	barrier();
 }
 
+/*
+ * Provide the necessary definitions for generic iomap. We make use of
+ * mips_io_port_base for iomap(), but we don't reserve any low addresses for
+ * use with I/O ports.
+ */
+#define HAVE_ARCH_PIO_SIZE
+#define PIO_OFFSET	mips_io_port_base
+#define PIO_MASK	IO_SPACE_LIMIT
+#define PIO_RESERVED	0x0UL
+
 /*
  * Thanks to James van Artsdalen for a better timing-fix than
  * the two short jumps: using outb's to a nonexistent port seems
@@ -172,11 +182,6 @@ static inline void *isa_bus_to_virt(unsigned long address)
 extern void __iomem * __ioremap(phys_addr_t offset, phys_addr_t size, unsigned long flags);
 extern void __iounmap(const volatile void __iomem *addr);
 
-#ifndef CONFIG_PCI
-struct pci_dev;
-static inline void pci_iounmap(struct pci_dev *dev, void __iomem *addr) {}
-#endif
-
 static inline void __iomem * __ioremap_mode(phys_addr_t offset, unsigned long size,
 	unsigned long flags)
 {

arch/mips/lib/Makefile

@@ -7,7 +7,7 @@ lib-y	+= bitops.o csum_partial.o delay.o memcpy.o memset.o \
 	   mips-atomic.o strncpy_user.o \
 	   strnlen_user.o uncached.o
 
-obj-y			+= iomap.o iomap_copy.o
+obj-y			+= iomap_copy.o
 obj-$(CONFIG_PCI)	+= iomap-pci.o
 lib-$(CONFIG_GENERIC_CSUM)	:= $(filter-out csum_partial.o, $(lib-y))
 

arch/mips/lib/iomap-pci.c

@@ -44,10 +44,3 @@ void __iomem *__pci_ioport_map(struct pci_dev *dev,
 }
 
 #endif /* CONFIG_PCI_DRIVERS_LEGACY */
-
-void pci_iounmap(struct pci_dev *dev, void __iomem * addr)
-{
-	iounmap(addr);
-}
-
-EXPORT_SYMBOL(pci_iounmap);

arch/mips/lib/iomap.c

@@ -1,227 +0,0 @@
-// SPDX-License-Identifier: GPL-2.0
-/*
- * Implement the default iomap interfaces
- *
- * (C) Copyright 2004 Linus Torvalds
- * (C) Copyright 2006 Ralf Baechle <ralf@linux-mips.org>
- * (C) Copyright 2007 MIPS Technologies, Inc.
- *     written by Ralf Baechle <ralf@linux-mips.org>
- */
-#include <linux/export.h>
-#include <asm/io.h>
-
-/*
- * Read/write from/to an (offsettable) iomem cookie. It might be a PIO
- * access or a MMIO access, these functions don't care. The info is
- * encoded in the hardware mapping set up by the mapping functions
- * (or the cookie itself, depending on implementation and hw).
- *
- * The generic routines don't assume any hardware mappings, and just
- * encode the PIO/MMIO as part of the cookie. They coldly assume that
- * the MMIO IO mappings are not in the low address range.
- *
- * Architectures for which this is not true can't use this generic
- * implementation and should do their own copy.
- */
-
-#define PIO_MASK	0x0ffffUL
-
-unsigned int ioread8(void __iomem *addr)
-{
-	return readb(addr);
-}
-
-EXPORT_SYMBOL(ioread8);
-
-unsigned int ioread16(void __iomem *addr)
-{
-	return readw(addr);
-}
-
-EXPORT_SYMBOL(ioread16);
-
-unsigned int ioread16be(void __iomem *addr)
-{
-	return be16_to_cpu(__raw_readw(addr));
-}
-
-EXPORT_SYMBOL(ioread16be);
-
-unsigned int ioread32(void __iomem *addr)
-{
-	return readl(addr);
-}
-
-EXPORT_SYMBOL(ioread32);
-
-unsigned int ioread32be(void __iomem *addr)
-{
-	return be32_to_cpu(__raw_readl(addr));
-}
-
-EXPORT_SYMBOL(ioread32be);
-
-void iowrite8(u8 val, void __iomem *addr)
-{
-	writeb(val, addr);
-}
-
-EXPORT_SYMBOL(iowrite8);
-
-void iowrite16(u16 val, void __iomem *addr)
-{
-	writew(val, addr);
-}
-
-EXPORT_SYMBOL(iowrite16);
-
-void iowrite16be(u16 val, void __iomem *addr)
-{
-	__raw_writew(cpu_to_be16(val), addr);
-}
-
-EXPORT_SYMBOL(iowrite16be);
-
-void iowrite32(u32 val, void __iomem *addr)
-{
-	writel(val, addr);
-}
-
-EXPORT_SYMBOL(iowrite32);
-
-void iowrite32be(u32 val, void __iomem *addr)
-{
-	__raw_writel(cpu_to_be32(val), addr);
-}
-
-EXPORT_SYMBOL(iowrite32be);
-
-/*
- * These are the "repeat MMIO read/write" functions.
- * Note the "__mem" accesses, since we want to convert
- * to CPU byte order if the host bus happens to not match the
- * endianness of PCI/ISA (see mach-generic/mangle-port.h).
- */
-static inline void mmio_insb(void __iomem *addr, u8 *dst, int count)
-{
-	while (--count >= 0) {
-		u8 data = __mem_readb(addr);
-		*dst = data;
-		dst++;
-	}
-}
-
-static inline void mmio_insw(void __iomem *addr, u16 *dst, int count)
-{
-	while (--count >= 0) {
-		u16 data = __mem_readw(addr);
-		*dst = data;
-		dst++;
-	}
-}
-
-static inline void mmio_insl(void __iomem *addr, u32 *dst, int count)
-{
-	while (--count >= 0) {
-		u32 data = __mem_readl(addr);
-		*dst = data;
-		dst++;
-	}
-}
-
-static inline void mmio_outsb(void __iomem *addr, const u8 *src, int count)
-{
-	while (--count >= 0) {
-		__mem_writeb(*src, addr);
-		src++;
-	}
-}
-
-static inline void mmio_outsw(void __iomem *addr, const u16 *src, int count)
-{
-	while (--count >= 0) {
-		__mem_writew(*src, addr);
-		src++;
-	}
-}
-
-static inline void mmio_outsl(void __iomem *addr, const u32 *src, int count)
-{
-	while (--count >= 0) {
-		__mem_writel(*src, addr);
-		src++;
-	}
-}
-
-void ioread8_rep(void __iomem *addr, void *dst, unsigned long count)
-{
-	mmio_insb(addr, dst, count);
-}
-
-EXPORT_SYMBOL(ioread8_rep);
-
-void ioread16_rep(void __iomem *addr, void *dst, unsigned long count)
-{
-	mmio_insw(addr, dst, count);
-}
-
-EXPORT_SYMBOL(ioread16_rep);
-
-void ioread32_rep(void __iomem *addr, void *dst, unsigned long count)
-{
-	mmio_insl(addr, dst, count);
-}
-
-EXPORT_SYMBOL(ioread32_rep);
-
-void iowrite8_rep(void __iomem *addr, const void *src, unsigned long count)
-{
-	mmio_outsb(addr, src, count);
-}
-
-EXPORT_SYMBOL(iowrite8_rep);
-
-void iowrite16_rep(void __iomem *addr, const void *src, unsigned long count)
-{
-	mmio_outsw(addr, src, count);
-}
-
-EXPORT_SYMBOL(iowrite16_rep);
-
-void iowrite32_rep(void __iomem *addr, const void *src, unsigned long count)
-{
-	mmio_outsl(addr, src, count);
-}
-
-EXPORT_SYMBOL(iowrite32_rep);
-
-/*
- * Create a virtual mapping cookie for an IO port range
- *
- * This uses the same mapping are as the in/out family which has to be setup
- * by the platform initialization code.
- *
- * Just to make matters somewhat more interesting on MIPS systems with
- * multiple host bridge each will have it's own ioport address space.
- */
-static void __iomem *ioport_map_legacy(unsigned long port, unsigned int nr)
-{
-	return (void __iomem *) (mips_io_port_base + port);
-}
-
-void __iomem *ioport_map(unsigned long port, unsigned int nr)
-{
-	if (port > PIO_MASK)
-		return NULL;
-
-	return ioport_map_legacy(port, nr);
-}
-
-EXPORT_SYMBOL(ioport_map);
-
-void ioport_unmap(void __iomem *addr)
-{
-	/* Nothing to do */
-}
-
-EXPORT_SYMBOL(ioport_unmap);