Better support memory mapped console devices, such as VGA and EFI

frame buffers and memory mapped UARTs.

1.  Delay calling cninit() until after pmap_bootstrap(). This makes
    sure we have PMAP initialized enough to add translations. Keep
    kdb_init() after cninit() so that we have console when we need
    to break into the debugger on boot.
2.  Unfortunately, the ATPIC code had be moved as well so as to
    avoid a spurious trap #30. The reason for which is not known
    at this time.
3.  In pmap_mapdev_attr(), when we need to map a device prior to the
    VM system being initialized, use virtual_avail as the KVA to map
    the device at. In particular, avoid using the direct map on amd64
    because we can't demote by virtue of not being able to allocate
    yet. Keep track of the translation.
    Re-use the translation after the VM has been initialized to not
    waste KVA and to satisfy the assumption in uart(4) that the handle
    returned for the low-level console is the same as later returned
    when the device is probed and attached.
4.  In pmap_unmapdev() remove the mapping from the table when called
    pre-init. Otherwise keep the mapping. During bus probe and attach
    device resources are mapped and unmapped multiple times, which
    would have us destroy the mapping used by the low-level console.
5.  In pmap_init(), set pmap_initialized to signal that we're not
    pre-init anymore. On amd64, bring the direct map in sync with the
    translations created at that time.
6.  Implement bus_space_map() and bus_space_unmap() for real: when
    the tag corresponds to memory space, call the corresponding
    pmap_mapdev() and pmap_unmapdev() functions to construct and
    actual handle.
7.  In efifb.c and vt_vga.c, remove the crutches and hacks and simply
    call pmap_mapdev_attr() or bus_space_map() as desired.

Notes:
1.  uart(4) already used bus_space_map() during low-level console
    setup but since serial ports have traditionally been I/O port
    based, the lack of a proper implementation for said function
    was not a problem. It has always supported memory mapped UARTs
    for low-level consoles by setting hw.uart.console accordingly.
2.  The use of the direct map on amd64 without setting caching
    attributes has been a bigger problem than previously thought.
    This change has the fortunate (and unexpected) side-effect of
    fixing various EFI frame buffer problems (though not all).

PR: 191564, 194952

Special thanks to:
1.  XipLink, Inc -- generously donated an Intel Bay Trail E3800
    based eval board (ADLE3800PC).
2.  The FreeBSD Foundation, in particular emaste@ -- for UEFI
    support in general and testing.
3.  Everyone who tested the proposed for PR 191564.
4.  jhb@ and kib@ for being a soundboard and applying a clue bat
    if so needed.

2 files changed, 63 insertions, 21 deletions

diff --git a/sys/x86/include/bus.h b/sys/x86/include/bus.h
index ced90d5..91de8cb 100644
--- a/sys/x86/include/bus.h
+++ b/sys/x86/include/bus.h
@@ -130,32 +130,15 @@
  * Map a region of device bus space into CPU virtual address space.
  */
 
-static __inline int bus_space_map(bus_space_tag_t t, bus_addr_t addr,
-				  bus_size_t size, int flags,
-				  bus_space_handle_t *bshp);
-
-static __inline int
-bus_space_map(bus_space_tag_t t __unused, bus_addr_t addr,
-	      bus_size_t size __unused, int flags __unused,
-	      bus_space_handle_t *bshp)
-{
-
-	*bshp = addr;
-	return (0);
-}
+int bus_space_map(bus_space_tag_t tag, bus_addr_t addr, bus_size_t size,
+    int flags, bus_space_handle_t *bshp);
 
 /*
  * Unmap a region of device bus space.
  */
 
-static __inline void bus_space_unmap(bus_space_tag_t t, bus_space_handle_t bsh,
-				     bus_size_t size);
-
-static __inline void
-bus_space_unmap(bus_space_tag_t t __unused, bus_space_handle_t bsh __unused,
-		bus_size_t size __unused)
-{
-}
+void bus_space_unmap(bus_space_tag_t tag, bus_space_handle_t bsh,
+    bus_size_t size);
 
 /*
  * Get a new handle for a subregion of an already-mapped area of bus space.
diff --git a/sys/x86/x86/bus_machdep.c b/sys/x86/x86/bus_machdep.c
new file mode 100644
index 0000000..a629a81
--- /dev/null
+++ b/sys/x86/x86/bus_machdep.c
@@ -0,0 +1,59 @@
+/*-
+ * Copyright (c) 2015 Marcel Moolenaar
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
+ * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
+ * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
+ * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
+ * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
+ * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include <sys/cdefs.h>
+__FBSDID("$FreeBSD$");
+
+#include <sys/param.h>
+#include <sys/systm.h>
+#include <x86/bus.h>
+
+#include <vm/vm.h>
+#include <vm/pmap.h>
+
+/*
+ * Implementation of bus_space_map(), which effectively is a thin
+ * wrapper around pmap_mapdev() for memory mapped I/O space. It's
+ * implemented here and not in <x86/bus.h> to avoid pollution.
+ */
+int
+bus_space_map(bus_space_tag_t tag, bus_addr_t addr, bus_size_t size,
+    int flags __unused, bus_space_handle_t *bshp)
+{
+
+	*bshp = (tag == X86_BUS_SPACE_MEM)
+	    ? (uintptr_t)pmap_mapdev(addr, size)
+	    : addr;
+	return (0);
+}
+
+void
+bus_space_unmap(bus_space_tag_t tag, bus_space_handle_t bsh, bus_size_t size)
+{
+
+	if (tag == X86_BUS_SPACE_MEM)
+		pmap_unmapdev(bsh, size);
+}