[PATCH 1/2] Type-safe ioport callbacks

[Avi Kivity <avi@redhat.com>]

The current ioport callbacks are not type-safe, in that they accept an "opaque"
pointer as an argument whose type must match the argument to the registration
function; this is not checked by the compiler.

This patch adds an alternative that is type-safe.  Instead of an opaque
argument, both registation and the callback use a new IOPort type.  The
callback then uses container_of() to access its main structures.

Currently the old and new methods exist side by side; once the old way is gone,
we can also save a bunch of memory since the new method requires one pointer
per ioport instead of 6.

Signed-off-by: Avi Kivity <avi@redhat.com>
---
 ioport.c |   64 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 ioport.h |   16 +++++++++++++++
 2 files changed, 80 insertions(+), 0 deletions(-)

diff --git a/ioport.c b/ioport.c
index ec3dc65..47eafc3 100644
--- a/ioport.c
+++ b/ioport.c
@@ -174,6 +174,70 @@ int register_ioport_write(pio_addr_t start, int length, int size,
     return 0;
 }
 
+static uint32_t ioport_readb_thunk(void *opaque, uint32_t addr)
+{
+    IOPort *ioport = opaque;
+
+    return ioport->ops->readb(ioport, addr);
+}
+
+static uint32_t ioport_readw_thunk(void *opaque, uint32_t addr)
+{
+    IOPort *ioport = opaque;
+
+    return ioport->ops->readw(ioport, addr);
+}
+
+static uint32_t ioport_readl_thunk(void *opaque, uint32_t addr)
+{
+    IOPort *ioport = opaque;
+
+    return ioport->ops->readl(ioport, addr);
+}
+
+static void ioport_writeb_thunk(void *opaque, uint32_t addr, uint32_t data)
+{
+    IOPort *ioport = opaque;
+
+    return ioport->ops->writeb(ioport, addr, data);
+}
+
+static void ioport_writew_thunk(void *opaque, uint32_t addr, uint32_t data)
+{
+    IOPort *ioport = opaque;
+
+    return ioport->ops->writew(ioport, addr, data);
+}
+
+static void ioport_writel_thunk(void *opaque, uint32_t addr, uint32_t data)
+{
+    IOPort *ioport = opaque;
+
+    return ioport->ops->writel(ioport, addr, data);
+}
+
+void ioport_register(IOPort *ioport, pio_addr_t start, pio_addr_t length)
+{
+    if (ioport->ops->readb) {
+        register_ioport_read(start, length, 1, ioport_readb_thunk, ioport);
+    }
+    if (ioport->ops->readw) {
+        register_ioport_read(start, length, 2, ioport_readw_thunk, ioport);
+    }
+    if (ioport->ops->readl) {
+        register_ioport_read(start, length, 4, ioport_readl_thunk, ioport);
+    }
+    if (ioport->ops->writeb) {
+        register_ioport_write(start, length, 1, ioport_writeb_thunk, ioport);
+    }
+    if (ioport->ops->writew) {
+        register_ioport_write(start, length, 2, ioport_writew_thunk, ioport);
+    }
+    if (ioport->ops->writel) {
+        register_ioport_write(start, length, 4, ioport_writel_thunk, ioport);
+    }
+}
+
 void isa_unassign_ioport(pio_addr_t start, int length)
 {
     int i;
diff --git a/ioport.h b/ioport.h
index 3d3c8a3..8036e59 100644
--- a/ioport.h
+++ b/ioport.h
@@ -36,6 +36,22 @@ typedef uint32_t pio_addr_t;
 typedef void (IOPortWriteFunc)(void *opaque, uint32_t address, uint32_t data);
 typedef uint32_t (IOPortReadFunc)(void *opaque, uint32_t address);
 
+struct IOPort;
+
+typedef struct IOPortOps {
+    uint32_t (*readb)(struct IOPort *ioport, pio_addr_t addr);
+    uint32_t (*readw)(struct IOPort *ioport, pio_addr_t addr);
+    uint32_t (*readl)(struct IOPort *ioport, pio_addr_t addr);
+    void (*writeb)(struct IOPort *ioport, pio_addr_t addr, uint32_t data);
+    void (*writew)(struct IOPort *ioport, pio_addr_t addr, uint32_t data);
+    void (*writel)(struct IOPort *ioport, pio_addr_t addr, uint32_t data);
+} IOPortOps;
+
+typedef struct IOPort {
+    IOPortOps *ops;
+} IOPort;
+
+void ioport_register(IOPort *ioport, pio_addr_t start, pio_addr_t length);
 int register_ioport_read(pio_addr_t start, int length, int size,
                          IOPortReadFunc *func, void *opaque);
 int register_ioport_write(pio_addr_t start, int length, int size,
-- 
1.7.3.1