sh: trapped io support V2

The idea is that we want to get rid of the in/out/readb/writeb callbacks from
the machvec and replace that with simple inline read and write operations to
memory. Fast and simple for most hardware devices (think pci).

Some devices require special treatment though - like 16-bit only CF devices -
so we need to have some method to hook in callbacks.

This patch makes it possible to add a per-device trap generating filter. This
way we can get maximum performance of sane hardware - which doesn't need this
filter - and crappy hardware works but gets punished by a performance hit.

V2 changes things around a bit and replaces io access callbacks with a
simple minimum_bus_width value. In the future we can add stride as well.

Signed-off-by: Magnus Damm <damm@igel.co.jp>
Signed-off-by: Paul Mundt <lethal@linux-sh.org>

1 files changed, 58 insertions, 0 deletions

diff --git a/include/asm-sh/io_trapped.h b/include/asm-sh/io_trapped.h
new file mode 100644
index 000000000000..f1251d4f0ba9
--- /dev/null
+++ b/include/asm-sh/io_trapped.h
@@ -0,0 +1,58 @@
+#ifndef __ASM_SH_IO_TRAPPED_H
+#define __ASM_SH_IO_TRAPPED_H
+
+#include <linux/list.h>
+#include <linux/ioport.h>
+#include <asm/page.h>
+
+#define IO_TRAPPED_MAGIC 0xfeedbeef
+
+struct trapped_io {
+        unsigned int magic;
+        struct resource *resource;
+        unsigned int num_resources;
+        unsigned int minimum_bus_width;
+        struct list_head list;
+        void __iomem *virt_base;
+} __aligned(PAGE_SIZE);
+
+#ifdef CONFIG_IO_TRAPPED
+int register_trapped_io(struct trapped_io *tiop);
+int handle_trapped_io(struct pt_regs *regs, unsigned long address);
+
+void __iomem *match_trapped_io_handler(struct list_head *list,
+                                       unsigned long offset,
+                                       unsigned long size);
+
+#ifdef CONFIG_HAS_IOMEM
+extern struct list_head trapped_mem;
+
+static inline void __iomem *
+__ioremap_trapped(unsigned long offset, unsigned long size)
+{
+        return match_trapped_io_handler(&trapped_mem, offset, size);
+}
+#else
+#define __ioremap_trapped(offset, size) NULL
+#endif
+
+#ifdef CONFIG_HAS_IOPORT
+extern struct list_head trapped_io;
+
+static inline void __iomem *
+__ioport_map_trapped(unsigned long offset, unsigned long size)
+{
+        return match_trapped_io_handler(&trapped_io, offset, size);
+}
+#else
+#define __ioport_map_trapped(offset, size) NULL
+#endif
+
+#else
+#define register_trapped_io(tiop) (-1)
+#define handle_trapped_io(tiop, address) 0
+#define __ioremap_trapped(offset, size) NULL
+#define __ioport_map_trapped(offset, size) NULL
+#endif
+
+#endif /* __ASM_SH_IO_TRAPPED_H */