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

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Message-ID: <20210315130928.42c65655@md1za8fc.ad001.siemens.net>
Date:   Mon, 15 Mar 2021 13:09:28 +0100
From:   Henning Schild <henning.schild@...mens.com>
To:     Hans de Goede <hdegoede@...hat.com>
Cc:     linux-kernel@...r.kernel.org, linux-leds@...r.kernel.org,
        platform-driver-x86@...r.kernel.org,
        linux-watchdog@...r.kernel.org,
        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

Am Mon, 15 Mar 2021 11:19:24 +0100
schrieb Hans de Goede <hdegoede@...hat.com>:

> 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.

Sounds good. I think i will make that another patch on top of the
series and send it in reply to "v2 4/4". Maybe squash it in a v3.

regards,
Henning

> Regards,
> 
> Hans
>