kernel/amd64: bus: Add bus abstraction layer

Signed-off-by: Ian Moffett <ian@osmora.org>

1 files changed, 80 insertions, 0 deletions

diff --git a/sys/arch/amd64/amd64/bus_machdep.c b/sys/arch/amd64/amd64/bus_machdep.c
new file mode 100644
index 0000000..5c0111d
--- /dev/null
+++ b/sys/arch/amd64/amd64/bus_machdep.c
@@ -0,0 +1,80 @@
+/*
+ * Copyright (c) 2023-2024 Ian Marco Moffett and the Osmora Team.
+ * 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.
+ * 3. Neither the name of Hyra nor the names of its
+ *    contributors may be used to endorse or promote products derived from
+ *    this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "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 COPYRIGHT OWNER OR CONTRIBUTORS 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/param.h>
+#include <sys/types.h>
+#include <sys/errno.h>
+#include <machine/bus.h>
+#include <vm/vm.h>
+#include <vm/map.h>
+#include <vm/pmap.h>
+
+/*
+ * Map a physical device address into the kernel address
+ * space.
+ *
+ * @addr: Physical address to map.
+ * @size: Size to map.
+ * @flags: Mapping flags.
+ * @vap: Resulting virtual address.
+ */
+int
+bus_map(bus_addr_t addr, size_t size, int flags, void **vap)
+{
+    struct vas vas;
+    int status;
+    vaddr_t va;
+    vm_prot_t prot = PROT_READ | PROT_WRITE;
+
+    /* Make sure we have a valid size */
+    if (size == 0) {
+        return -EINVAL;
+    }
+
+    size = ALIGN_UP(size, DEFAULT_PAGESIZE);
+    va = (vaddr_t)PHYS_TO_VIRT(addr);
+    vas = pmap_read_vas();
+
+    /* Now map it to the higher half */
+    if ((status = vm_map(vas, va, addr, prot, size)) != 0) {
+        return status;
+    }
+
+    /*
+     * Mark the memory as uncachable as this is for device I/O
+     * and we do not want to get stale data.
+     */
+    if ((status = pmap_set_cache(vas, va, VM_CACHE_UC)) != 0) {
+        vm_unmap(vas, va, size);
+        return status;
+    }
+
+    *vap = (void *)va;
+    return 0;
+}