kernel/amd64: bus: Add bus resource interface

This commit introduces a bus resource abstraction. A bus resource
encapsulates bus specific information and semantics. Along with
abstracting away bus specific details and providing an overall
smoother interface, this additionally provides flexibility, access
control and security by keeping track of permissions and allowing
things to be turned on or off.

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

1 files changed, 74 insertions, 0 deletions

diff --git a/sys/arch/amd64/amd64/bus_machdep.c b/sys/arch/amd64/amd64/bus_machdep.c
index d542821..89ef317 100644
--- a/sys/arch/amd64/amd64/bus_machdep.c
+++ b/sys/arch/amd64/amd64/bus_machdep.c
@@ -34,6 +34,52 @@
 #include <vm/vm.h>
 #include <vm/map.h>
 #include <vm/pmap.h>
+#include <vm/dynalloc.h>
+#include <dev/pci/resource.h>
+#include <string.h>
+
+#define BUS_PCI "PCI"
+#define BUS_LPC "LPC"
+
+/*
+ * Set bus specific fields
+ *
+ * @brp: Bus resource pointer.
+ * @type: Bus name/signature
+ *
+ * XXX: Assumes brp->base has already been set to
+ *      a valid bus address.
+ */
+static int
+bus_set(struct bus_resource *brp, const char *type)
+{
+    struct bus_op *io = &brp->io;
+
+    switch (*type) {
+    case 'P':
+        if (strcmp(type, BUS_PCI) == 0) {
+            /*
+             * Bus addresses for 64-bit PCI can theoretically
+             * span 2^64 bytes (i.e., the full 64-bit address space)
+             */
+            brp->dma_max = (bus_addr_t)-1;
+            brp->dma_min = 0;
+
+            /* Set hooks */
+            io->enable_dma = pcir_enable_dma;
+            io->disable_dma = pcir_disable_dma;
+            io->set_sem = pcir_set_sem;
+            io->clr_sem = pcir_clr_sem;
+            io->dma_alloc = pcir_dma_alloc;
+            io->dma_free = pcir_dma_free;
+            io->dma_in = pcir_dma_in;
+            io->dma_out = pcir_dma_out;
+            return 0;
+        }
+    }
+
+    return -ENODEV;
+}
 
 /*
  * Map a physical device address into the kernel address
@@ -78,3 +124,31 @@ bus_map(bus_addr_t addr, size_t size, int flags, void **vap)
     *vap = (void *)va;
     return 0;
 }
+
+/*
+ * Associate a specific bus with a 'bus_resource`
+ * structure.
+ *
+ * @name: Signature.
+ */
+struct bus_resource *
+bus_establish(const char *name)
+{
+    struct bus_resource *brp;
+    size_t siglen;
+
+    siglen = strlen(name);
+    if (siglen > RSIG_MAX) {
+        return NULL;
+    }
+
+    /* Allocate a new bus resource handle */
+    if ((brp = dynalloc(sizeof(*brp))) == NULL) {
+        return NULL;
+    }
+
+    memset(brp, 0, sizeof(*brp));
+    memcpy(brp->signature, name, siglen);
+    bus_set(brp, name);
+    return brp;
+}