linux-kernel - Re: [PATCH v2 4/4] platform/x86: pmc_atom: improve critclk

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Date:   Mon, 15 Mar 2021 11:19:24 +0100
From:   Hans de Goede <hdegoede@...hat.com>
To:     Henning Schild <henning.schild@...mens.com>,
        linux-kernel@...r.kernel.org, linux-leds@...r.kernel.org,
        platform-driver-x86@...r.kernel.org, linux-watchdog@...r.kernel.org
Cc:     Srikanth Krishnakar <skrishnakar@...il.com>,
        Jan Kiszka <jan.kiszka@...mens.com>,
        Gerd Haeussler <gerd.haeussler.ext@...mens.com>,
        Guenter Roeck <linux@...ck-us.net>,
        Wim Van Sebroeck <wim@...ux-watchdog.org>,
        Mark Gross <mgross@...ux.intel.com>,
        Pavel Machek <pavel@....cz>,
        Andy Shevchenko <andy.shevchenko@...il.com>,
        Michael Haener <michael.haener@...mens.com>
Subject: Re: [PATCH v2 4/4] platform/x86: pmc_atom: improve critclk_systems
 matching for Siemens PCs

Hi,

On 3/15/21 11:14 AM, Henning Schild wrote:
> Am Mon, 15 Mar 2021 10:57:10 +0100
> schrieb Henning Schild <henning.schild@...mens.com>:
> 
>> Siemens industrial PCs unfortunately can not always be properly
>> identified the way we used to. An earlier commit introduced code that
>> allows proper identification without looking at DMI strings that could
>> differ based on product branding.
>> Switch over to that proper way and revert commits that used to collect
>> the machines based on unstable strings.
>>
>> Fixes: 648e921888ad ("clk: x86: Stop marking clocks as
>> CLK_IS_CRITICAL") Fixes: e8796c6c69d1 ("platform/x86: pmc_atom: Add
>> Siemens CONNECT ...") Fixes: f110d252ae79 ("platform/x86: pmc_atom:
>> Add Siemens SIMATIC ...") Fixes: ad0d315b4d4e ("platform/x86:
>> pmc_atom: Add Siemens SIMATIC ...") Tested-by: Michael Haener
>> <michael.haener@...mens.com> Signed-off-by: Henning Schild
>> <henning.schild@...mens.com> ---
>>  drivers/platform/x86/pmc_atom.c | 47
>> +++++++++++++++++++-------------- 1 file changed, 27 insertions(+),
>> 20 deletions(-)
>>
>> diff --git a/drivers/platform/x86/pmc_atom.c
>> b/drivers/platform/x86/pmc_atom.c index ca684ed760d1..38542d547f29
>> 100644 --- a/drivers/platform/x86/pmc_atom.c
>> +++ b/drivers/platform/x86/pmc_atom.c
>> @@ -13,6 +13,7 @@
>>  #include <linux/io.h>
>>  #include <linux/platform_data/x86/clk-pmc-atom.h>
>>  #include <linux/platform_data/x86/pmc_atom.h>
>> +#include <linux/platform_data/x86/simatic-ipc.h>
>>  #include <linux/platform_device.h>
>>  #include <linux/pci.h>
>>  #include <linux/seq_file.h>
>> @@ -362,6 +363,23 @@ static void pmc_dbgfs_register(struct pmc_dev
>> *pmc) }
>>  #endif /* CONFIG_DEBUG_FS */
>>  
>> +static bool pmc_clk_is_critical = true;
>> +
>> +static int siemens_clk_is_critical(const struct dmi_system_id *d)
>> +{
>> +	u32 st_id;
>> +
>> +	if (dmi_walk(simatic_ipc_find_dmi_entry_helper, &st_id))
>> +		goto out;
>> +
>> +	if (st_id == SIMATIC_IPC_IPC227E || st_id ==
>> SIMATIC_IPC_IPC277E)
>> +		return 1;
>> +
>> +out:
>> +	pmc_clk_is_critical = false;
>> +	return 1;
>> +}
>> +
>>  /*
>>   * Some systems need one or more of their pmc_plt_clks to be
>>   * marked as critical.
>> @@ -424,24 +442,10 @@ static const struct dmi_system_id
>> critclk_systems[] = { },
>>  	},
>>  	{
>> -		.ident = "SIMATIC IPC227E",
>> -		.matches = {
>> -			DMI_MATCH(DMI_SYS_VENDOR, "SIEMENS AG"),
>> -			DMI_MATCH(DMI_PRODUCT_VERSION, "6ES7647-8B"),
>> -		},
>> -	},
>> -	{
>> -		.ident = "SIMATIC IPC277E",
>> -		.matches = {
>> -			DMI_MATCH(DMI_SYS_VENDOR, "SIEMENS AG"),
>> -			DMI_MATCH(DMI_PRODUCT_VERSION, "6AV7882-0"),
>> -		},
>> -	},
>> -	{
>> -		.ident = "CONNECT X300",
>> +		.callback = siemens_clk_is_critical,
>> +		.ident = "SIEMENS AG",
>>  		.matches = {
>>  			DMI_MATCH(DMI_SYS_VENDOR, "SIEMENS AG"),
>> -			DMI_MATCH(DMI_PRODUCT_VERSION,
>> "A5E45074588"), },
>>  	},
>>  
>> @@ -453,7 +457,7 @@ static int pmc_setup_clks(struct pci_dev *pdev,
>> void __iomem *pmc_regmap, {
>>  	struct platform_device *clkdev;
>>  	struct pmc_clk_data *clk_data;
>> -	const struct dmi_system_id *d =
>> dmi_first_match(critclk_systems);
>> +	const struct dmi_system_id *d;
>>  
>>  	clk_data = kzalloc(sizeof(*clk_data), GFP_KERNEL);
>>  	if (!clk_data)
>> @@ -461,9 +465,12 @@ static int pmc_setup_clks(struct pci_dev *pdev,
>> void __iomem *pmc_regmap, 
>>  	clk_data->base = pmc_regmap; /* offset is added by client */
>>  	clk_data->clks = pmc_data->clks;
>> -	if (d) {
>> -		clk_data->critical = true;
>> -		pr_info("%s critclks quirk enabled\n", d->ident);
>> +	if (dmi_check_system(critclk_systems)) {
> 
> Had to switch to check_system to get the callback to work.
> 
>> +		clk_data->critical = pmc_clk_is_critical;
>> +		if (clk_data->critical) {
>> +			d = dmi_first_match(critclk_systems);
>> +			pr_info("%s critclks quirk enabled\n",
>> d->ident);
> 
> Now need a double match here just to print the ident. Not too happy
> with that but proposing it like this to keep the ident printing.
> 
> I guess it could be improved by not printing the ident or having a
> global variable and global callback to remember the ident to print
> later. I would propose to not print the ident if the double-match does
> not find traction.

IMHO it would be best to add another callback for the non Siemens
entries which just prints the ideent and returns 1 to avoid needsly
looping over the rest of the array.

And then just set the callback member of all the non Siemens entries
to this new callback. The space for the callback pointer is already
reserved in the struct anyways, so actually setting it does not take
up any space.

Regards,

Hans