Re: [Qemu-devel] [PATCH] hw/arm/allwinner-a10: Add the 'A' SRAM and the SRAM controller

[Peter Maydell]

On Sun, 9 Dec 2018 at 19:37, Philippe Mathieu-Daudé <address@hidden> wrote:
>
> From the "A10 User Manual V1.20" p.29: "3.2. Memory Mapping" and:
>
>  7. System Control
>   7.1. Overview
>
>   A10 embeds a high-speed SRAM which has been split into five segments.
>   See detailed memory mapping in following table:
>
>   Area          Address        Size (Bytes)
>    A1    0x00000000-0x00003FFF 16K
>    A2    0x00004000-0x00007FFF 16K
>    A3    0x00008000-0x0000B3FF 13K
>    A4    0x0000B400-0x0000BFFF  3K
>
> Since for emulation purpose we don't need the segmentations, we simply define
> the 'A' area as a single 48KB SRAM.

>  static void aw_a10_init(Object *obj)
>  {
> @@ -85,6 +86,10 @@ static void aw_a10_realize(DeviceState *dev, Error **errp)
>      sysbus_connect_irq(sysbusdev, 4, s->irq[67]);
>      sysbus_connect_irq(sysbusdev, 5, s->irq[68]);
>
> +    memory_region_init_ram(&s->sram_a, NULL, "sram A", 48 * KiB, 
> &error_fatal);

This creates the memory region with a NULL owner, which is
OK for board model code, but since we're a device object
here we should use OBJECT(dev) as the owner.

This is more important if the region creation happens
in the instance_init function, in which case it will
result in a leak of the memory region after the device
is destroyed (see for instance commit 09d98b69804cfd9e),
but it's worth getting right here anyway.

> +    memory_region_add_subregion(get_system_memory(), 0x00000000, &s->sram_a);
> +    create_unimplemented_device("a10-sram-ctrl", 0x01c00000, 4 * KiB);
> +
>      /* FIXME use qdev NIC properties instead of nd_table[] */
>      if (nd_table[0].used) {
>          qemu_check_nic_model(&nd_table[0], TYPE_AW_EMAC);

thanks
-- PMM