On 23/03/2023 14:45, Souradeep Chowdhury wrote:
>
>
> On 3/22/2023 8:23 PM, Krzysztof Kozlowski wrote:
>> On 22/03/2023 14:54, Souradeep Chowdhury wrote:
>>>
>>>
>>> On 3/21/2023 11:07 PM, Krzysztof Kozlowski wrote:
>>>> On 21/03/2023 14:51, Souradeep Chowdhury wrote:
>>>>> All of Qualcomm's proprietary Android boot-loaders capture boot time
>>>>> stats, like the time when the bootloader started execution and at what
>>>>> point the bootloader handed over control to the kernel etc. in the IMEM
>>>>> region. This information is captured in a specific format by this driver
>>>>> by mapping a structure to the IMEM memory region and then accessing the
>>>>> members of the structure to print the information. This information is
>>>>> useful in verifying if the existing boot KPIs have regre
>>>>
>>>>
>>>>> +/**
>>>>> + * struct boot_stats - timestamp information related to boot stats
>>>>> + * @bootloader_start: Time for the starting point of the abl bootloader
>>>>> + * @bootloader_end: Time when the kernel starts loading from abl bootloader
>>>>> + */
>>>>> +struct boot_stats {
>>>>> + u32 bootloader_start;
>>>>> + u32 bootloader_end;
>>>>> +} __packed;
>>>>> +
>>>>> +static struct boot_stats __iomem *boot_stats;
>>>>> +static void __iomem *mpm_counter_base;
>>>>> +static u32 mpm_counter_freq;
>>>>
>>>> No file-scope variables. Does not scale, not easy for review and
>>>> maintenance. Avoid such code.
>>>
>>> Ack
>>>>
>>>>> +
>>>>> +static int mpm_parse_dt(void)
>>>>> +{
>>>>> + struct device_node *np_imem, *np_mpm2;
>>>>> +
>>>>> + np_imem = of_find_compatible_node(NULL, NULL,
>>>>> + "qcom,imem-boot_stats");
>>>>> + if (!np_imem) {
>>>>> + pr_err("can't find qcom,imem node\n");
>>>>
>>>> So you are printing errors everywhere, on every soc and with compile
>>>> test on every platform there is in the world... sorry, it does not work
>>>> like that.
>>>
>>> Ack
>>>>
>>>>> + return -ENODEV;
>>>>> + }
>>>>> + boot_stats = of_iomap(np_imem, 0);
>>>>> + if (!boot_stats) {
>>>>> + pr_err("boot_stats: Can't map imem\n");
>>>>> + goto err1;
>>>>> + }
>>>>
>>>>
>>>>> +
>>>>> +static void __exit boot_stats_exit(void)
>>>>> +{
>>>>> +}
>>>>> +module_exit(boot_stats_exit)
>>>>
>>>>
>>>> I don't think this is some special code which deserves init calls. Make
>>>> it module_platform_driver().
>>>
>>> Since this just reads some values from the Imem region and prints it to
>>> the user and doesn't have a specific device associated with it, a
>>
>> Which is not really an argument for such antipattern, but okay...
>>
>>> generic module code is written for it and not a module_platform_driver().
>>
>> ... so how do you handle deferred probe?
>
> This has no dependency on other resources except that it parses some
> information from DT nodes, so deferred probe handling is not needed
> in this case.
Yes, I know, but if we would ever add it how this driver can handle it?
This is antipattern.
Best regards,
Krzysztof
