[PATCH v2 2/3] hw/char/mchp_pfsoc_mmuart: Use a MemoryRegion container

["Philippe Mathieu-Daudé" <f4bug@amsat.org>]

Our device have 2 different I/O regions:
- a 16550 UART mapped for 32-bit accesses
- 13 extra registers

Instead of mapping each region on the main bus, introduce
a container, map the 2 devices regions on the container,
and map the container on the main bus.

Before:

  (qemu) info mtree
    ...
    0000000020100000-000000002010001f (prio 0, i/o): serial
    0000000020100020-000000002010101f (prio 0, i/o): mchp.pfsoc.mmuart
    0000000020102000-000000002010201f (prio 0, i/o): serial
    0000000020102020-000000002010301f (prio 0, i/o): mchp.pfsoc.mmuart
    0000000020104000-000000002010401f (prio 0, i/o): serial
    0000000020104020-000000002010501f (prio 0, i/o): mchp.pfsoc.mmuart
    0000000020106000-000000002010601f (prio 0, i/o): serial
    0000000020106020-000000002010701f (prio 0, i/o): mchp.pfsoc.mmuart

After:

  (qemu) info mtree
    ...
    0000000020100000-0000000020100fff (prio 0, i/o): mchp.pfsoc.mmuart
      0000000020100000-000000002010001f (prio 0, i/o): serial
      0000000020100020-0000000020100fff (prio 0, i/o): mchp.pfsoc.mmuart.regs
    0000000020102000-0000000020102fff (prio 0, i/o): mchp.pfsoc.mmuart
      0000000020102000-000000002010201f (prio 0, i/o): serial
      0000000020102020-0000000020102fff (prio 0, i/o): mchp.pfsoc.mmuart.regs
    0000000020104000-0000000020104fff (prio 0, i/o): mchp.pfsoc.mmuart
      0000000020104000-000000002010401f (prio 0, i/o): serial
      0000000020104020-0000000020104fff (prio 0, i/o): mchp.pfsoc.mmuart.regs
    0000000020106000-0000000020106fff (prio 0, i/o): mchp.pfsoc.mmuart
      0000000020106000-000000002010601f (prio 0, i/o): serial
      0000000020106020-0000000020106fff (prio 0, i/o): mchp.pfsoc.mmuart.regs

Signed-off-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
---
 include/hw/char/mchp_pfsoc_mmuart.h |  1 +
 hw/char/mchp_pfsoc_mmuart.c         | 11 ++++++++---
 2 files changed, 9 insertions(+), 3 deletions(-)

diff --git a/include/hw/char/mchp_pfsoc_mmuart.h b/include/hw/char/mchp_pfsoc_mmuart.h
index 9c012e6c977..864ac1a36b5 100644
--- a/include/hw/char/mchp_pfsoc_mmuart.h
+++ b/include/hw/char/mchp_pfsoc_mmuart.h
@@ -33,6 +33,7 @@
 #define MCHP_PFSOC_MMUART_REG_COUNT 13
 
 typedef struct MchpPfSoCMMUartState {
+    MemoryRegion container;
     MemoryRegion iomem;
     hwaddr base;
     qemu_irq irq;
diff --git a/hw/char/mchp_pfsoc_mmuart.c b/hw/char/mchp_pfsoc_mmuart.c
index 584e7fec17c..ea586559761 100644
--- a/hw/char/mchp_pfsoc_mmuart.c
+++ b/hw/char/mchp_pfsoc_mmuart.c
@@ -25,6 +25,8 @@
 #include "chardev/char.h"
 #include "hw/char/mchp_pfsoc_mmuart.h"
 
+#define REGS_OFFSET 0x20
+
 static uint64_t mchp_pfsoc_mmuart_read(void *opaque, hwaddr addr, unsigned size)
 {
     MchpPfSoCMMUartState *s = opaque;
@@ -72,16 +74,19 @@ MchpPfSoCMMUartState *mchp_pfsoc_mmuart_create(MemoryRegion *sysmem,
 
     s = g_new0(MchpPfSoCMMUartState, 1);
 
+    memory_region_init(&s->container, NULL, "mchp.pfsoc.mmuart", 0x1000);
+
     memory_region_init_io(&s->iomem, NULL, &mchp_pfsoc_mmuart_ops, s,
-                          "mchp.pfsoc.mmuart", 0x1000);
+                          "mchp.pfsoc.mmuart.regs", 0x1000 - REGS_OFFSET);
+    memory_region_add_subregion(&s->container, REGS_OFFSET, &s->iomem);
 
     s->base = base;
     s->irq = irq;
 
-    s->serial = serial_mm_init(sysmem, base, 2, irq, 399193, chr,
+    s->serial = serial_mm_init(&s->container, 0, 2, irq, 399193, chr,
                                DEVICE_LITTLE_ENDIAN);
 
-    memory_region_add_subregion(sysmem, base + 0x20, &s->iomem);
+    memory_region_add_subregion(sysmem, base, &s->container);
 
     return s;
 }
-- 
2.31.1