On Tue, Aug 25, 2015 at 09:43:14PM +0800, Haojian Zhuang wrote:
> On Tue, 2015-08-25 at 11:42 +0100, Mark Rutland wrote:
> > > > Are you then going to hack GRUB, release a special HiKey version of
> > > > GRUB, not support any other versions, and still can your firmware
> > > > UEFI?
> > >
> > > I don't need to hack GRUB at all.
> >
> > Then it is working for you by pure chance alone.
> >
> > Please listen to the advice you are being given here; we're trying to
> > ensure that your platform functions (and continues to function) as best
> > it can.
>
> Since we discussed a lot on this, let's make a conclusion on it.
>
> 1. UEFI could append the reserved buffer in it's memory mapping.
> 2. These reserved buffer must be declared in DT, since we also need to
> support non-UEFI (uboot) at the same time.
> 3. Mailbox node should reference reserved buffer by phandle in DT. Then
> map the buffer as non-cacheable in driver.
> 4. These reserved buffer must use "no-map" property since it should be
> non-cacheable in driver.
For more specific discussion for DTS, i list two options at here;
- Option 1: just simply reserve memory regions through memory node,
and mailbox node will directly use the buffer through reg ranges;
- Option 2: use reserved-memory and mailbox node will refer phandle
of reserved-memory;
These two options both can work well with UEFI and Uboot, but option 1
is more simple and straightforward; so i personally prefer it. But
look forwarding your guys' suggestion.
Option 1:
memory@0 {
device_type = "memory";
reg = <0x00000000 0x00000000 0x00000000 0x05e00000>,
<0x00000000 0x05f00000 0x00000000 0x00eff000>,
<0x00000000 0x06e00000 0x00000000 0x0060f000>,
<0x00000000 0x07410000 0x00000000 0x38bf0000>;
};
[...]
mailbox: mailbox@f7510000 {
#mbox-cells = <1>;
compatible = "hisilicon,hi6220-mbox";
reg = <0x0 0xf7510000 0x0 0x1000>, /* IPC_S */
<0x0 0x06dff800 0x0 0x0800>; /* Mailbox buffer */
interrupts = <GIC_SPI 94 IRQ_TYPE_LEVEL_HIGH>;
};
Option 2:
memory@0 {
device_type = "memory";
reg = <0x0 0x0 0x0 0x40000000>;
};
reserved-memory {
#address-cells = <2>;
#size-cells = <2>;
ranges;
mcu_reserved: mcu_reserved@06dff000 {
no-map;
reg = <0x0 0x06dff000 0x0 0x00001000>, /* MCU mailbox buffer */
<0x0 0x05e00000 0x0 0x00100000>, /* MCU firmware buffer */
<0x0 0x0740f000 0x0 0x00001000>; /* MCU firmware section */
};
};
[...]
mailbox: mailbox@f7510000 {
#mbox-cells = <1>;
compatible = "hisilicon,hi6220-mbox";
reg = <0x0 0xf7510000 0x0 0x1000>; /* IPC_S */
memory-region = <&mcu_reserved>; /* Mailbox buffer */
interrupts = <GIC_SPI 94 IRQ_TYPE_LEVEL_HIGH>;
};
> 5. A patch is necessary in kernel. If efi stub feature is enabled,
> arm kernel should not parse memory node or reserved memory buffer in
> DT any more. Arm kernel should either fetch memory information from
> efi or DT. Currently arm kernel fetch both efi memory information and
> reserved buffer from DTB at the same time.
>
> Do you agree on these points?
>
> Regards
> Haojian
>
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