Re: [PATCH v5 17/79] arm/integratorcp: use memdev for RAM

[Igor Mammedov <imammedo@redhat.com>]

On Tue, 18 Feb 2020 07:55:14 +0100
Philippe Mathieu-Daudé <philmd@redhat.com> wrote:

> On 2/17/20 6:33 PM, Igor Mammedov wrote:
> > memory_region_allocate_system_memory() API is going away, so
> > replace it with memdev allocated MemoryRegion. The later is
> > initialized by generic code, so board only needs to opt in
> > to memdev scheme by providing
> >    MachineClass::default_ram_id
> > and using MachineState::ram instead of manually initializing
> > RAM memory region.
> > 
> > Signed-off-by: Igor Mammedov <imammedo@redhat.com>
> > Reviewed-by: Andrew Jones <drjones@redhat.com>
> > ---
> > CC: peter.chubb@nicta.com.au
> > ---
> >   hw/arm/integratorcp.c | 9 ++++-----
> >   1 file changed, 4 insertions(+), 5 deletions(-)
> > 
> > diff --git a/hw/arm/integratorcp.c b/hw/arm/integratorcp.c
> > index 0cd94d9f09..cc845b8534 100644
> > --- a/hw/arm/integratorcp.c
> > +++ b/hw/arm/integratorcp.c
> > @@ -585,7 +585,6 @@ static void integratorcp_init(MachineState *machine)
> >       Object *cpuobj;
> >       ARMCPU *cpu;
> >       MemoryRegion *address_space_mem = get_system_memory();
> > -    MemoryRegion *ram = g_new(MemoryRegion, 1);
> >       MemoryRegion *ram_alias = g_new(MemoryRegion, 1);
> >       qemu_irq pic[32];
> >       DeviceState *dev, *sic, *icp;
> > @@ -605,14 +604,13 @@ static void integratorcp_init(MachineState *machine)
> >   
> >       cpu = ARM_CPU(cpuobj);
> >   
> > -    memory_region_allocate_system_memory(ram, NULL, "integrator.ram",
> > -                                         ram_size);
> >       /* ??? On a real system the first 1Mb is mapped as SSRAM or boot flash.  */
> >       /* ??? RAM should repeat to fill physical memory space.  */
> >       /* SDRAM at address zero*/
> > -    memory_region_add_subregion(address_space_mem, 0, ram);
> > +    memory_region_add_subregion(address_space_mem, 0, machine->ram);
> >       /* And again at address 0x80000000 */
> > -    memory_region_init_alias(ram_alias, NULL, "ram.alias", ram, 0, ram_size);
> > +    memory_region_init_alias(ram_alias, NULL, "ram.alias", machine->ram,
> > +                             0, ram_size);
> >       memory_region_add_subregion(address_space_mem, 0x80000000, ram_alias);
> >   
> >       dev = qdev_create(NULL, TYPE_INTEGRATOR_CM);
> > @@ -660,6 +658,7 @@ static void integratorcp_machine_init(MachineClass *mc)
> >       mc->init = integratorcp_init;
> >       mc->ignore_memory_transaction_failures = true;
> >       mc->default_cpu_type = ARM_CPU_TYPE_NAME("arm926");
> > +    mc->default_ram_id = "integrator.ram";
> >   }
> >   
> >   DEFINE_MACHINE("integratorcp", integratorcp_machine_init)
> >   
> 
> Looking at integratorcm_realize() this machine seems to handle at most 
> 512MiB.

According to 
http://infocenter.arm.com/help/index.jsp?topic=/com.arm.doc.dui0159b/Cegeadbj.html

it supports "optionally, 16 to 256MB of SDRAM plugged into the DIMM socket"
so I'm not sure that realize is valid reference here.
(well I don't know anything about arm boards, but it probably should be
double checked by maintainer).

PS:
It should not hold this series (as check wasn't there to begin with),
I'll post a patch on top to add check once we decide to what limit it
should be set.