Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20;
Message-ID: <6b016170-0d01-ebb3-a47e-4107cabc4403@quicinc.com>
Date:   Fri, 13 Jan 2023 18:54:19 +0530
MIME-Version: 1.0
User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:91.0) Gecko/20100101
 Thunderbird/91.13.1
Subject: Re: [PATCH v2 2/3] Documentation: admin-guide: ramoops.rst: Update
 the ramoops document
Content-Language: en-US
To:     <keescook@chromium.org>, <gpiccoli@igalia.com>, <corbet@lwn.net>,
        <tony.luck@intel.com>, <robh+dt@kernel.org>,
        <krzysztof.kozlowski+dt@linaro.org>
CC:     <linux-hardening@vger.kernel.org>, <linux-doc@vger.kernel.org>,
        <linux-kernel@vger.kernel.org>, <devicetree@vger.kernel.org>
References: <1673611126-13803-1-git-send-email-quic_mojha@quicinc.com>
 <1673611126-13803-2-git-send-email-quic_mojha@quicinc.com>
From:   Mukesh Ojha <quic_mojha@quicinc.com>
In-Reply-To: <1673611126-13803-2-git-send-email-quic_mojha@quicinc.com>
Content-Type: text/plain; charset="UTF-8"; format=flowed
Content-Transfer-Encoding: 7bit
Precedence: bulk

Hi,

On 1/13/2023 5:28 PM, Mukesh Ojha wrote:
> The reserved memory region for ramoops is assumed to be at a fixed
> and known location when read from the devicetree. This is not desirable
> in environments where it is preferred the region to be dynamically
> allocated at runtime. So, update the document while adding the
> support in the driver.
> 
> Signed-off-by: Mukesh Ojha <quic_mojha@quicinc.com>
> ---
> Change in v2:
>    - Added this patch as per changes going to be done in patch 3/3
> 
>   Documentation/admin-guide/ramoops.rst | 25 ++++++++++++++++++++++---
>   1 file changed, 22 insertions(+), 3 deletions(-)
> 
> diff --git a/Documentation/admin-guide/ramoops.rst b/Documentation/admin-guide/ramoops.rst
> index e9f8514..88884b2 100644
> --- a/Documentation/admin-guide/ramoops.rst
> +++ b/Documentation/admin-guide/ramoops.rst
> @@ -16,8 +16,9 @@ survive after a restart.
>   Ramoops concepts
>   ----------------
>   
> -Ramoops uses a predefined memory area to store the dump. The start and size
> -and type of the memory area are set using three variables:
> +Ramoops uses both predefined and dynamically memory area to store the dump.
> +The start and size and type of the memory area are set using three
> +variables:
>   
>     * ``mem_address`` for the start
>     * ``mem_size`` for the size. The memory size will be rounded down to a
> @@ -70,7 +71,8 @@ Setting the ramoops parameters can be done in several different manners:
>   
>    B. Use Device Tree bindings, as described in
>    ``Documentation/devicetree/bindings/reserved-memory/ramoops.yaml``.
> - For example::
> +
> + Example of statically reserved ramoops region::
>   
>   	reserved-memory {
>   		#address-cells = <2>;
> @@ -85,6 +87,23 @@ Setting the ramoops parameters can be done in several different manners:
>   		};
>   	};
>   
> + Example of dynamically reserved ramoops region::
> +
> +	reserved-memory {
> +		#address-cells = <2>;
> +		#size-cells = <2>;
> +		ranges;
> +
> +		ramoops@8f000000 {

Will fix it as ramoops_region : ramoops ?

> +			compatible = "ramoops";
> +			alloc-ranges = <0x0 0x00000000 0xffffffff 0xffffffff>;
> +			size = <0 0x100000>;
> +			record-size = <0x4000>;
> +			console-size = <0x4000>;
> +		};
> +	};
> +
> +
>    C. Use a platform device and set the platform data. The parameters can then
>    be set through that platform data. An example of doing that is:
>   

-Mukesh