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

[Alistair Francis]

On Sat, Sep 25, 2021 at 11:34 PM Philippe Mathieu-Daudé <f4bug@amsat.org> wrote:
>
> 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>

Reviewed-by: Alistair Francis <alistair.francis@wdc.com>

Alistair

> ---
>  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
>