On Wed, 2015-08-26 at 00:00 +0800, Leo Yan wrote:
> 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>;
> };
I prefer the second one. From my view, memory node should only describe
the hardware information of memory.
Regards
Haojian
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