From: Hans de Goede <hdegoede@redhat.com>
To: Andy Shevchenko <andy.shevchenko@gmail.com>
Cc: Henning Schild <henning.schild@siemens.com>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
Linux LED Subsystem <linux-leds@vger.kernel.org>,
Platform Driver <platform-driver-x86@vger.kernel.org>,
linux-watchdog@vger.kernel.org,
Srikanth Krishnakar <skrishnakar@gmail.com>,
Jan Kiszka <jan.kiszka@siemens.com>,
Gerd Haeussler <gerd.haeussler.ext@siemens.com>,
Guenter Roeck <linux@roeck-us.net>,
Wim Van Sebroeck <wim@linux-watchdog.org>,
Mark Gross <mgross@linux.intel.com>, Pavel Machek <pavel@ucw.cz>
Subject: Re: [PATCH 1/4] platform/x86: simatic-ipc: add main driver for Siemens devices
Date: Fri, 5 Mar 2021 17:14:29 +0100 [thread overview]
Message-ID: <ec54b2ba-3eb2-0981-e409-4d8f9d3e45c1@redhat.com> (raw)
In-Reply-To: <CAHp75VfB8v1n3Hav_oMqG0k4C31NBEUe082i8NrrOGUbSgoESw@mail.gmail.com>
Hi,
On 3/5/21 4:42 PM, Andy Shevchenko wrote:
> On Thu, Mar 4, 2021 at 3:47 PM Hans de Goede <hdegoede@redhat.com> wrote:
>> On 3/4/21 11:11 AM, Andy Shevchenko wrote:
>>> On Thu, Mar 4, 2021 at 8:36 AM Henning Schild
>>> <henning.schild@siemens.com> wrote:
>
> ...
>
>>>> +u32 simatic_ipc_get_membase0(unsigned int p2sb)
>>>> +{
>>>> + u32 bar0 = 0;
>>>
>>>> +#ifdef CONFIG_PCI
>>>
>>> It's ugly besides the fact that you have a dependency.
>>>
>>>> + struct pci_bus *bus;
>>>
>>> Missed blank line.
>>>
>>>> + /*
>>>> + * The GPIO memory is bar0 of the hidden P2SB device. Unhide the device
>>>> + * to have a quick look at it, before we hide it again.
>>>> + * Also grab the pci rescan lock so that device does not get discovered
>>>> + * and remapped while it is visible.
>>>> + * This code is inspired by drivers/mfd/lpc_ich.c
>>>> + */
>>>> + bus = pci_find_bus(0, 0);
>>>> + pci_lock_rescan_remove();
>>>> + pci_bus_write_config_byte(bus, p2sb, 0xE1, 0x0);
>>>> + pci_bus_read_config_dword(bus, p2sb, PCI_BASE_ADDRESS_0, &bar0);
>>>> +
>>>> + bar0 &= ~0xf;
>>>> + pci_bus_write_config_byte(bus, p2sb, 0xE1, 0x1);
>>>> + pci_unlock_rescan_remove();
>>>> +#endif /* CONFIG_PCI */
>>>> + return bar0;
>>>> +}
>>>> +EXPORT_SYMBOL(simatic_ipc_get_membase0);
>>>
>>> Oy vey! I know what this is and let's do it differently. I have some
>>> (relatively old) patch series I can send you privately for testing.
>>
>> This bit stood out the most to me too, it would be good if we can this fixed
>> in some cleaner work. So I'm curious how things will look with Andy's work
>> integrated.
>>
>> Also I don't think this should be exported. Instead this (or its replacement)
>> should be used to get the address for an IOMEM resource to add the platform
>> devices when they are instantiated. Then the platform-dev drivers can just
>> use the regular functions to get their resources instead of relying on this
>> module.
>
> I have published a WIP branch [1]. I have no means to test (I don't
> know what hardware at hand I can use right now), but I made it compile
> after 4 years of gathering dust...
So I took a quick look at the following 2 commits:
"platform/x86: p2sb: New Primary to Sideband bridge support library"
"mfd: lpc_ich: Switch to generic p2sb_bar()"
And this looks good to me, although compared to the code from this
patch-set you are missing the pci_lock_rescan_remove(); and
pci_unlock_rescan_remove(); calls.
> Feel free to give any kind of comments or share your ideas on how it
> can be improved (the above idea on IOMEM resource is interesting, but
> devices are PCI, not sure how this can be done).
The code added by this patch introduces a register_platform_devices()
function which creates a bunch of platform-devices; and then the
device-drivers for those call simatic_ipc_get_membase0() to get their
base-address.
My suggestion was to instead put the simatic_ipc_get_membase0() call
inside the code instantiating the platform devices and to add the
base-address for that pdev as IOMEM resource to the instantiated
platform-devices.
I hope this helps to clarify what I was trying to say.
Regards,
Hans
next prev parent reply other threads:[~2021-03-05 16:15 UTC|newest]
Thread overview: 46+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-03-02 16:33 [PATCH 0/4] add device drivers for Siemens Industrial PCs Henning Schild
2021-03-02 16:33 ` [PATCH 1/4] platform/x86: simatic-ipc: add main driver for Siemens devices Henning Schild
2021-03-04 10:11 ` Andy Shevchenko
2021-03-04 13:47 ` Hans de Goede
2021-03-05 15:42 ` Andy Shevchenko
2021-03-05 16:14 ` Hans de Goede [this message]
2021-03-05 16:25 ` Andy Shevchenko
2021-03-05 16:36 ` Hans de Goede
2021-03-05 16:41 ` Andy Shevchenko
2021-03-05 16:47 ` Andy Shevchenko
2021-03-05 16:42 ` Henning Schild
2021-03-05 17:17 ` Andy Shevchenko
2021-03-05 17:44 ` Andy Shevchenko
2021-03-08 12:57 ` Henning Schild
2021-03-08 13:43 ` Andy Shevchenko
2021-03-04 19:42 ` Henning Schild
2021-03-05 15:46 ` Andy Shevchenko
2021-03-05 16:31 ` Henning Schild
2021-03-04 14:03 ` Hans de Goede
2021-03-02 16:33 ` [PATCH 2/4] leds: simatic-ipc-leds: add new driver for Siemens Industial PCs Henning Schild
2021-03-02 20:54 ` Pavel Machek
2021-03-03 13:11 ` Henning Schild
2021-03-03 19:31 ` Pavel Machek
2021-03-03 20:48 ` Henning Schild
2021-03-03 20:56 ` Henning Schild
2021-03-05 18:25 ` Henning Schild
2021-03-06 12:54 ` Henning Schild
2021-03-06 13:06 ` Henning Schild
2021-03-15 11:49 ` Pavel Machek
2021-03-15 11:41 ` Pavel Machek
2021-03-03 17:37 ` Henning Schild
2021-03-03 17:40 ` Pavel Machek
2021-03-03 18:49 ` Henning Schild
2021-03-03 19:27 ` Pavel Machek
2021-03-02 16:33 ` [PATCH 3/4] watchdog: simatic-ipc-wdt: add new driver for Siemens Industrial PCs Henning Schild
2021-03-02 18:38 ` Guenter Roeck
2021-03-03 14:21 ` Henning Schild
2021-03-03 14:49 ` Jan Kiszka
2021-03-08 15:20 ` Henning Schild
[not found] ` <CAHp75VdUXWDg-2o8fmeo7EoMtRLfCnFOw5ptwjXTv9fKMmHv2A@mail.gmail.com>
2021-03-04 9:00 ` Henning Schild
2021-03-02 16:33 ` [PATCH 4/4] platform/x86: pmc_atom: improve critclk_systems matching for Siemens PCs Henning Schild
2021-03-04 9:50 ` Andy Shevchenko
2021-03-04 10:19 ` [PATCH 0/4] add device drivers for Siemens Industrial PCs Andy Shevchenko
2021-03-04 10:20 ` Andy Shevchenko
2021-03-04 19:26 ` Henning Schild
2021-03-04 19:14 ` Henning Schild
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