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Message-ID: <c265d22e-c246-4c9f-b6ff-7a350468e28c@quicinc.com>
Date: Thu, 20 Jun 2024 21:40:52 +0800
From: Tengfei Fan <quic_tengfan@...cinc.com>
To: Caleb Connolly <caleb.connolly@...aro.org>, <andersson@...nel.org>,
<konrad.dybcio@...aro.org>, <robh@...nel.org>, <krzk+dt@...nel.org>,
<conor+dt@...nel.org>, <dmitry.baryshkov@...aro.org>
CC: <linux-arm-msm@...r.kernel.org>, <devicetree@...r.kernel.org>,
<linux-kernel@...r.kernel.org>, <kernel@...cinc.com>
Subject: Re: [PATCH v10 2/4] arm64: dts: qcom: qcs8550: introduce qcs8550 dtsi
On 6/18/2024 6:06 PM, Caleb Connolly wrote:
> HI Tengfei,
>
> On 18/06/2024 09:22, Tengfei Fan wrote:
>> QCS8550 is derived from SM8550. The difference between SM8550 and
>> QCS8550 is QCS8550 doesn't have modem RF system. QCS8550 is mainly used
>> in IoT products.
>> QCS8550 firmware has different memory map compared to SM8550.
>> The memory map will be runtime added through bootloader.
>> There are 3 types of reserved memory regions here:
>> 1. Firmware related regions which aren't shared with kernel.
>> The device tree source in kernel doesn't need to have node to
>> indicate
>> the firmware related reserved information. Bootloader converys the
>> information by updating devicetree at runtime.
>> This will be described as: UEFI saves the physical address of the
>> UEFI System Table to dts file's chosen node. Kernel read this table and
>> add reserved memory regions to efi config table. Current reserved memory
>> region may have reserved region which was not yet used, release note of
>> the firmware have such kind of information.
>> 2. Firmware related memory regions which are shared with Kernel
>> The device tree source in the kernel needs to include nodes that
>> indicate fimware-related shared information. A label name is suggested
>> because this type of shared information needs to be referenced by
>> specific drivers for handling purposes.
>> Unlike previous platforms, QCS8550 boots using EFI and describes
>> most reserved regions in the ESRT memory map. As a result, reserved
>> memory regions which aren't relevant to the kernel(like the hypervisor
>> region) don't need to be described in DT.
>> 3. Remoteproc regions.
>> Remoteproc regions will be reserved and then assigned to subsystem
>> firmware later.
>> Here is a reserved memory map for this platform:
>> 0x80000000 +-------------------+
>> | |
>> | Firmware Related |
>> | |
>> 0x8a800000 +-------------------+
>> | |
>> | Remoteproc Region |
>> | |
>> 0xa7000000 +-------------------+
>> | |
>> | Kernel Available |
>> | |
>> 0xd4d00000 +-------------------+
>> | |
>> | Firmware Related |
>> | |
>> 0x100000000 +-------------------+
>>
>> Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@...aro.org>
>> Signed-off-by: Tengfei Fan <quic_tengfan@...cinc.com>
>> ---
>> arch/arm64/boot/dts/qcom/qcs8550.dtsi | 162 ++++++++++++++++++++++++++
>> 1 file changed, 162 insertions(+)
>> create mode 100644 arch/arm64/boot/dts/qcom/qcs8550.dtsi
>>
>> diff --git a/arch/arm64/boot/dts/qcom/qcs8550.dtsi
>> b/arch/arm64/boot/dts/qcom/qcs8550.dtsi
>> new file mode 100644
>> index 000000000000..07b314834d88
>> --- /dev/null
>> +++ b/arch/arm64/boot/dts/qcom/qcs8550.dtsi
>> @@ -0,0 +1,162 @@
>> +// SPDX-License-Identifier: BSD-3-Clause
>> +/*
>> + * Copyright (c) 2023-2024, Qualcomm Innovation Center, Inc. All
>> rights reserved.
>> + */
>> +
>> +#include "sm8550.dtsi"
>> +
>> +/delete-node/ &reserved_memory;
>> +
>> +/ {
>> + reserved_memory: reserved-memory {
>> + #address-cells = <2>;
>> + #size-cells = <2>;
>> + ranges;
>> +
>> +
>> + /* These are 3 types of reserved memory regions here:
>> + * 1. Firmware related regions which aren't shared with kernel.
>> + * The device tree source in kernel doesn't need to have
>> node to
>> + * indicate the firmware related reserved information.
>> Bootloader
>> + * conveys the information by updating devicetree at runtime.
>> + * This will be described as: UEFI saves the physical
>> address of
>> + * the UEFI System Table to dts file's chosen node. Kernel
>> read this
>> + * table and add reserved memory regions to efi config table.
>> Current
>> + * reserved memory region may have reserved region which was
>> not yet
>> + * used, release note of the firmware have such kind of
>> information.
>
> This is a lot of implementation detail about UEFI, I'd imagine that
> anyone curious can go read the relevant docs instead. It's a lot of
> words just to say "Firmware regions which the kernel doesn't need to
> know about which are not included in the EFI provided memory map."
The following update will be applied to this point:
1. Firmware related regions which aren't shared with kernel.
Firmware regions which the kernel doesn't need to know about which
are not included in the EFI provided memory map.
>> + * 2. Firmware related memory regions which are shared with
>> Kernel
>> + * The device tree source in the kernel needs to include
>> nodes
>> + * that indicate fimware-related shared information. A label
>> name
>> + * is suggested because this type of shared information needs to
>> + * be referenced by specific drivers for handling purposes.
>
> "Firmware regions the kernel DOES need to know about, which are
> described in the reserved-memory node".
The following update will be applied to this point:
2. Firmware related memory regions which are shared with Kernel
Firmware regions the kernel does need to know about, which are described
in the reserved-memory node.
>> + * Unlike previous platforms, QCS8550 boots using EFI and
>> describes
>> + * most reserved regions in the ESRT memory map. As a result,
>> reserved
>> + * memory regions which aren't relevant to the kernel(like
>> the hypervisor
>> + ( region) don't need to be described in DT.
>
> These would fall under (1) "firmware the kernel doesn't need to know about"
This will be removed from its current position.
>> + * 3. Remoteproc regions.
>> + * Remoteproc regions will be reserved and then assigned to
>> + * subsystem firmware later.
>
> How do these differ from those described in (2)?
This point will do the following update:
3. Remoteproc regions
Remoteproc regions will be reserved and then assigned to subsystem
firmware later.
Remoteproc regions can be loaded either in a fixed form or in a
relocatable form, depending on the platform.
>
> I think this comment is trying to describe too much at once. You're
> trying to describe what the different types of reserved memory are, how
> the kernel learns about them, and how this differs from previous
> platforms all at once. I think you should tackle these points separately:
>
> First describe the types of reserved memory and how the kernel learns
> about them (my suggestions above). Then describe the differences with
> previous platforms (like the hypervisor example)
>
> Thanks and regards,
Your previous suggestion will be incorporated here as follows:
Unlike previous platforms, QCS8550 boots using EFI and describes most
reserved regions in the ESRT memory map. As a result, reserved memory
regions which aren't relevant to the kernel(like the hypervisor region)
don't need to be described in DT.
Is it reasonable to place it here?
Thanks!
>> + * Here is a reserved memory map for this platform:
>> + * 0x80000000 +-------------------+
>> + * | |
>> + * | Firmware Related |
>> + * | |
>> + * 0x8a800000 +-------------------+
>> + * | |
>> + * | Remoteproc Region |
>> + * | |
>> + * 0xa7000000 +-------------------+
>> + * | |
>> + * | Kernel Available |
>> + * | |
>> + * 0xd4d00000 +-------------------+
>> + * | |
>> + * | Firmware Related |
>> + * | |
>> + * 0x100000000 +-------------------+
>> + */
>> +
>> + aop_image_mem: aop-image-region@...00000 {
>> + reg = <0x0 0x81c00000 0x0 0x60000>;
>> + no-map;
>> + };
>> +
>> + aop_cmd_db_mem: aop-cmd-db-region@...60000 {
>> + compatible = "qcom,cmd-db";
>> + reg = <0x0 0x81c60000 0x0 0x20000>;
>> + no-map;
>> + };
>> +
>> + aop_config_mem: aop-config-region@...80000 {
>> + no-map;
>> + reg = <0x0 0x81c80000 0x0 0x20000>;
>> + };
>> +
>> + smem_mem: smem-region@...00000 {
>> + compatible = "qcom,smem";
>> + reg = <0x0 0x81d00000 0x0 0x200000>;
>> + hwlocks = <&tcsr_mutex 3>;
>> + no-map;
>> + };
>> +
>> + adsp_mhi_mem: adsp-mhi-region@...00000 {
>> + reg = <0x0 0x81f00000 0x0 0x20000>;
>> + no-map;
>> + };
>> +
>> + mpss_mem: mpss-region@...00000 {
>> + reg = <0x0 0x8a800000 0x0 0x10800000>;
>> + no-map;
>> + };
>> +
>> + q6_mpss_dtb_mem: q6-mpss-dtb-region@...00000 {
>> + reg = <0x0 0x9b000000 0x0 0x80000>;
>> + no-map;
>> + };
>> +
>> + ipa_fw_mem: ipa-fw-region@...80000 {
>> + reg = <0x0 0x9b080000 0x0 0x10000>;
>> + no-map;
>> + };
>> +
>> + ipa_gsi_mem: ipa-gsi-region@...90000 {
>> + reg = <0x0 0x9b090000 0x0 0xa000>;
>> + no-map;
>> + };
>> +
>> + gpu_micro_code_mem: gpu-micro-code-region@...9a000 {
>> + reg = <0x0 0x9b09a000 0x0 0x2000>;
>> + no-map;
>> + };
>> +
>> + spss_region_mem: spss-region@...00000 {
>> + reg = <0x0 0x9b100000 0x0 0x180000>;
>> + no-map;
>> + };
>> +
>> + spu_secure_shared_memory_mem:
>> spu-secure-shared-memory-region@...80000 {
>> + reg = <0x0 0x9b280000 0x0 0x80000>;
>> + no-map;
>> + };
>> +
>> + camera_mem: camera-region@...00000 {
>> + reg = <0x0 0x9b300000 0x0 0x800000>;
>> + no-map;
>> + };
>> +
>> + video_mem: video-region@...00000 {
>> + reg = <0x0 0x9bb00000 0x0 0x700000>;
>> + no-map;
>> + };
>> +
>> + cvp_mem: cvp-region@...00000 {
>> + reg = <0x0 0x9c200000 0x0 0x700000>;
>> + no-map;
>> + };
>> +
>> + cdsp_mem: cdsp-region@...00000 {
>> + reg = <0x0 0x9c900000 0x0 0x2000000>;
>> + no-map;
>> + };
>> +
>> + q6_cdsp_dtb_mem: q6-cdsp-dtb-region@...00000 {
>> + reg = <0x0 0x9e900000 0x0 0x80000>;
>> + no-map;
>> + };
>> +
>> + q6_adsp_dtb_mem: q6-adsp-dtb-region@...80000 {
>> + reg = <0x0 0x9e980000 0x0 0x80000>;
>> + no-map;
>> + };
>> +
>> + adspslpi_mem: adspslpi-region@...00000 {
>> + reg = <0x0 0x9ea00000 0x0 0x4080000>;
>> + no-map;
>> + };
>> +
>> + mpss_dsm_mem: mpss_dsm_region@...00000 {
>> + reg = <0x0 0xd4d00000 0x0 0x3300000>;
>> + no-map;
>> + };
>> + };
>> +};
>
--
Thx and BRs,
Tengfei Fan
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