[PATCH 2/3] riscv: dts: spacemit: Move UARTs under dma-bus for K1
Vivian Wang
wangruikang at iscas.ac.cn
Tue Jun 24 05:51:51 PDT 2025
On 6/24/25 20:21, Guodong Xu wrote:
> On Mon, Jun 23, 2025 at 6:04 PM Vivian Wang <wangruikang at iscas.ac.cn> wrote:
>> UART devices in Spacemit K1 use dma-bus DMA translations. Move these
>> nodes under dma-bus to reflect this fact.
...
>>
>> - sec_uart1: serial at f0612000 {
>> - compatible = "spacemit,k1-uart", "intel,xscale-uart";
>> - reg = <0x0 0xf0612000 0x0 0x100>;
>> - interrupts = <43>;
>> - clock-frequency = <14857000>;
>> - reg-shift = <2>;
>> - reg-io-width = <4>;
>> - status = "reserved"; /* for TEE usage */
>> - };
>> -
> Are you sure sec_uart1 should be placed under the dma_bus? Please double
> check. If sec_uart1 and other peripherals supported by the secure DMA
> (base address: 0xF0600000) share the same address mapping as dma_bus, and
> if they can be accessed by the linux kernel in some cases (as saying
> 'reserved'), then that makes sense. If not, better not move them.
Bianbu's DT from SpacemiT [1] shows sec_uart1 using dram_range4, and it
made sense to me. However just to be sure I will ask SpacemiT for
confirmation.
Vivian "dramforever" Wang
[1]: https://gitee.com/bianbu-linux/linux-6.6/blob/k1-bl-v2.2.y/arch/riscv/boot/dts/spacemit/k1-x.dtsi
> --
> Guodong
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