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Message-ID: <580f629d-6fae-4cf7-9137-f98b901ae29d@linaro.org>
Date: Tue, 4 Jun 2024 13:20:25 +0200
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Subject: Re: [PATCH v9 2/4] arm64: dts: qcom: qcs8550: introduce qcs8550 dtsi
To: "Aiqun Yu (Maria)" <quic_aiquny@quicinc.com>,
 Tengfei Fan <quic_tengfan@quicinc.com>, andersson@kernel.org,
 konrad.dybcio@linaro.org, robh@kernel.org, krzk+dt@kernel.org,
 conor+dt@kernel.org, dmitry.baryshkov@linaro.org
Cc: linux-arm-msm@vger.kernel.org, devicetree@vger.kernel.org,
 linux-kernel@vger.kernel.org, kernel@quicinc.com
References: <20240529100926.3166325-1-quic_tengfan@quicinc.com>
 <20240529100926.3166325-3-quic_tengfan@quicinc.com>
 <a95fed63-f48d-42c6-856b-0636a50c9dd4@linaro.org>
 <18ff1bf2-be4d-4d82-a4b3-28242b1d1d59@quicinc.com>
Content-Language: en-US
From: Caleb Connolly <caleb.connolly@linaro.org>
In-Reply-To: <18ff1bf2-be4d-4d82-a4b3-28242b1d1d59@quicinc.com>
Content-Type: text/plain; charset=UTF-8; format=flowed
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On 04/06/2024 12:51, Aiqun Yu (Maria) wrote:
> 
> 
> On 6/3/2024 5:20 PM, Caleb Connolly wrote:
>> Hi Tengfei,
>>
>> On 29/05/2024 12:09, 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.
>>
>> Are you describing some particular quirk of the platform here, or just
>> standard UEFI booting?
> 
> It's standard UEFI booting efi config table.

Ok, thanks for confirming.
>>
>> When booting with UEFI, the memory map is passed via the ESRT, so having
>> memory that the kernel shouldn't use it pretty simple (and typical).

woo! \o/
> 
> yes. It is very simple. And the bootloader firmware config the
> "reserved" region in the efi config table from the uefi firmware.
>>> 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.
>>
>> Again, is there something non-standard here? If not I would suggest
>> dropping these detail comments as they might be misleading.
> 
> Detailed comments is used to describe current device tree reserved
> memory regions.
> 
> Current patch is not creating a new mechanism to have memory map
> described. But it is the first time qcom device trees use this design,
> and have a simplified(also more compatible) device tree reserved memory
> region(memory map). Previously, bootloader(apps bootloader) only pass
> the whole physical memory base and size, and use reserved memory nodes
> only in device tree(which is also a standard choose).
> 
> So that's why it is detailed comments for other qcom platform reference.

Doesn't the rb3gen2 also use this design?
> 
>>
>> Thanks and regards,
>>> 3. Remoteproc regions.
>>>       Remoteproc regions will be reserved and then assigned to subsystem
>>> firmware later.
>>> Here is a reserved memory map for this platform:
>>> 0x100000000 +-------------------+
>>>               |                   |
>>>               | Firmware Related  |
>>>               |                   |
>>>    0xd4d00000 +-------------------+
>>>               |                   |
>>>               | Kernel Available  |
>>>               |                   |
>>>    0xa7000000 +-------------------+
>>>               |                   |
>>>               | Remoteproc Region |
>>>               |                   |
>>>    0x8a800000 +-------------------+
>>>               |                   |
>>>               | Firmware Related  |
>>>               |                   |
>>>    0x80000000 +-------------------+
>>>
>>> Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
>>> Signed-off-by: Tengfei Fan <quic_tengfan@quicinc.com>
>>> ---
>>>    arch/arm64/boot/dts/qcom/qcs8550.dtsi | 167 ++++++++++++++++++++++++++
>>>    1 file changed, 167 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..685668c6ad14
>>> --- /dev/null
>>> +++ b/arch/arm64/boot/dts/qcom/qcs8550.dtsi
>>> @@ -0,0 +1,167 @@
>>> +// 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.
>>> +         * 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.
>>> +         * 3. Remoteproc regions.
>>> +         *     Remoteproc regions will be reserved and then assigned to
>>> +         * subsystem firmware later.
>>> +         * Here is a reserved memory map for this platform:
>>> +         * 0x100000000 +-------------------+
>>> +         *             |                   |
>>> +         *             | Firmware Related  |
>>> +         *             |                   |
>>> +         *  0xd4d00000 +-------------------+
>>> +         *             |                   |
>>> +         *             | Kernel Available  |
>>> +         *             |                   |
>>> +         *  0xa7000000 +-------------------+
>>> +         *             |                   |
>>> +         *             | Remoteproc Region |
>>> +         *             |                   |
>>> +         *  0x8a800000 +-------------------+
>>> +         *             |                   |
>>> +         *             | Firmware Related  |
>>> +         *             |                   |
>>> +         *  0x80000000 +-------------------+
>>> +         */
>>> +
>>> +        /*
>>> +         * Firmware related regions, bootloader will possible reserve
>>> parts of
>>> +         * region from 0x80000000..0x8a800000.
>>> +         */
>>> +        aop_image_mem: aop-image-region@81c00000 {
>>> +            reg = <0x0 0x81c00000 0x0 0x60000>;
>>> +            no-map;
>>> +        };
>>> +
>>> +        aop_cmd_db_mem: aop-cmd-db-region@81c60000 {
>>> +            compatible = "qcom,cmd-db";
>>> +            reg = <0x0 0x81c60000 0x0 0x20000>;
>>> +            no-map;
>>> +        };
>>> +
>>> +        aop_config_mem: aop-config-region@81c80000 {
>>> +            no-map;
>>> +            reg = <0x0 0x81c80000 0x0 0x20000>;
>>> +        };
>>> +
>>> +        smem_mem: smem-region@81d00000 {
>>> +            compatible = "qcom,smem";
>>> +            reg = <0x0 0x81d00000 0x0 0x200000>;
>>> +            hwlocks = <&tcsr_mutex 3>;
>>> +            no-map;
>>> +        };
>>> +
>>> +        adsp_mhi_mem: adsp-mhi-region@81f00000 {
>>> +            reg = <0x0 0x81f00000 0x0 0x20000>;
>>> +            no-map;
>>> +        };
>>> +
>>> +        /* PIL region */
>>> +        mpss_mem: mpss-region@8a800000 {
>>> +            reg = <0x0 0x8a800000 0x0 0x10800000>;
>>> +            no-map;
>>> +        };
>>> +
>>> +        q6_mpss_dtb_mem: q6-mpss-dtb-region@9b000000 {
>>> +            reg = <0x0 0x9b000000 0x0 0x80000>;
>>> +            no-map;
>>> +        };
>>> +
>>> +        ipa_fw_mem: ipa-fw-region@9b080000 {
>>> +            reg = <0x0 0x9b080000 0x0 0x10000>;
>>> +            no-map;
>>> +        };
>>> +
>>> +        ipa_gsi_mem: ipa-gsi-region@9b090000 {
>>> +            reg = <0x0 0x9b090000 0x0 0xa000>;
>>> +            no-map;
>>> +        };
>>> +
>>> +        gpu_micro_code_mem: gpu-micro-code-region@9b09a000 {
>>> +            reg = <0x0 0x9b09a000 0x0 0x2000>;
>>> +            no-map;
>>> +        };
>>> +
>>> +        spss_region_mem: spss-region@9b100000 {
>>> +            reg = <0x0 0x9b100000 0x0 0x180000>;
>>> +            no-map;
>>> +        };
>>> +
>>> +        spu_secure_shared_memory_mem:
>>> spu-secure-shared-memory-region@9b280000 {
>>> +            reg = <0x0 0x9b280000 0x0 0x80000>;
>>> +            no-map;
>>> +        };
>>> +
>>> +        camera_mem: camera-region@9b300000 {
>>> +            reg = <0x0 0x9b300000 0x0 0x800000>;
>>> +            no-map;
>>> +        };
>>> +
>>> +        video_mem: video-region@9bb00000 {
>>> +            reg = <0x0 0x9bb00000 0x0 0x700000>;
>>> +            no-map;
>>> +        };
>>> +
>>> +        cvp_mem: cvp-region@9c200000 {
>>> +            reg = <0x0 0x9c200000 0x0 0x700000>;
>>> +            no-map;
>>> +        };
>>> +
>>> +        cdsp_mem: cdsp-region@9c900000 {
>>> +            reg = <0x0 0x9c900000 0x0 0x2000000>;
>>> +            no-map;
>>> +        };
>>> +
>>> +        q6_cdsp_dtb_mem: q6-cdsp-dtb-region@9e900000 {
>>> +            reg = <0x0 0x9e900000 0x0 0x80000>;
>>> +            no-map;
>>> +        };
>>> +
>>> +        q6_adsp_dtb_mem: q6-adsp-dtb-region@9e980000 {
>>> +            reg = <0x0 0x9e980000 0x0 0x80000>;
>>> +            no-map;
>>> +        };
>>> +
>>> +        adspslpi_mem: adspslpi-region@9ea00000 {
>>> +            reg = <0x0 0x9ea00000 0x0 0x4080000>;
>>> +            no-map;
>>> +        };
>>> +
>>> +        /*
>>> +         * Firmware related regions, bootloader will possible reserve
>>> parts of
>>> +         * region from 0xd8000000..0x100000000.
>>> +         */
>>> +        mpss_dsm_mem: mpss_dsm_region@d4d00000 {
>>> +            reg = <0x0 0xd4d00000 0x0 0x3300000>;
>>> +            no-map;
>>> +        };
>>> +    };
>>> +};
>>
> 

-- 
// Caleb (they/them)