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From: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
To: Henning Schild <henning.schild@siemens.com>
Cc: Wolfram Sang <wsa+renesas@sang-engineering.com>,
	Jean Delvare <jdelvare@suse.de>, Lee Jones <lee.jones@linaro.org>,
	Tan Jui Nee <jui.nee.tan@intel.com>,
	Jim Quinlan <james.quinlan@broadcom.com>,
	Jonathan Yong <jonathan.yong@intel.com>,
	Bjorn Helgaas <bhelgaas@google.com>,
	linux-kernel@vger.kernel.org, linux-i2c@vger.kernel.org,
	linux-pci@vger.kernel.org, Jean Delvare <jdelvare@suse.com>,
	Peter Tyser <ptyser@xes-inc.com>,
	hdegoede@redhat.com,
	Mika Westerberg <mika.westerberg@linux.intel.com>
Subject: Re: [PATCH v1 3/7] PCI: New Primary to Sideband (P2SB) bridge support library
Date: Thu, 1 Apr 2021 18:43:11 +0300	[thread overview]
Message-ID: <YGXqDxSJhCO9bD1X@smile.fi.intel.com> (raw)
In-Reply-To: <20210313104557.321de08e@md1za8fc.ad001.siemens.net>

On Sat, Mar 13, 2021 at 10:45:57AM +0100, Henning Schild wrote:
> Am Mon, 8 Mar 2021 14:20:16 +0200
> schrieb Andy Shevchenko <andriy.shevchenko@linux.intel.com>:

...

> > + * pci_p2sb_bar - Get Primary to Sideband bridge (P2SB) device BAR
> > + * @pdev:	PCI device to get a PCI bus to communicate with
> > + * @devfn:	PCI slot and function to communicate with
> > + * @mem:	memory resource to be filled in
> 
> Do we really need that many arguments to it?
> 
> Before i had, in a platform driver that never had its own pci_dev or bus
> 
>   res->start = simatic_ipc_get_membase0(PCI_DEVFN(13, 0));
>   if (res-start == 0)
>     return -ENODEV;
> 
> So helper only asked for the devfn, returned base and no dedicated
> error code.
> 
> With this i need
> 
>   struct pci_bus *bus = pci_find_bus(0, 0);
>   struct pci_dev *pci_dev = bus->self;
>   unsigned int magic_i_do_not_want =  PCI_DEVFN(13, 0);

What confuses me is the use for SPI NOR controller on Broxton. And I think
we actually can indeed hide all this under the hood by exposing P2SB to the OS.

Mika, what do you think?

> I guess that second devfn is for devices behind that bridge. So
> unhiding it might reveal several devices?

Good question. I need a device where actually this happens (hidden P2SB stuff
with let's say SPI NOR there) to see how it looks like in such case. I only
understood the GPIO part. But I'm not so sure anymore.

> But when caring about that
> p2sb do i really need to know its devfn. If so i would like to get

-- 
With Best Regards,
Andy Shevchenko



  reply	other threads:[~2021-04-01 18:45 UTC|newest]

Thread overview: 54+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-03-08 12:20 [rfc, PATCH v1 0/7] PCI: introduce p2sb helper Andy Shevchenko
2021-03-08 12:20 ` [PATCH v1 1/7] PCI: Introduce pci_bus_*() printing macros when device is not available Andy Shevchenko
2021-03-10 14:57   ` Jean Delvare
2021-03-08 12:20 ` [PATCH v1 2/7] PCI: Convert __pci_read_base() to __pci_bus_read_base() Andy Shevchenko
2021-03-10 17:14   ` Christoph Hellwig
2021-03-08 12:20 ` [PATCH v1 3/7] PCI: New Primary to Sideband (P2SB) bridge support library Andy Shevchenko
2021-03-08 18:52   ` Bjorn Helgaas
2021-03-08 19:16     ` Andy Shevchenko
2021-03-09  1:42       ` Bjorn Helgaas
2021-03-09  8:42         ` Henning Schild
2021-04-01 15:45           ` Andy Shevchenko
2021-04-01 16:42             ` Bjorn Helgaas
2021-04-01 18:23               ` Andy Shevchenko
2021-04-01 18:44                 ` Bjorn Helgaas
2021-07-12 12:15                   ` Andy Shevchenko
2021-11-26 15:10                     ` Andy Shevchenko
2021-04-02 13:09           ` Enrico Weigelt, metux IT consult
2021-04-06 13:40             ` Henning Schild
2021-07-12 12:11               ` Andy Shevchenko
2021-11-26 15:38         ` Andy Shevchenko
2021-11-29 21:07           ` Bjorn Helgaas
2021-12-08 17:51             ` Andy Shevchenko
2021-03-13  9:45   ` Henning Schild
2021-04-01 15:43     ` Andy Shevchenko [this message]
2021-04-01 18:06       ` Mika Westerberg
2021-04-01 18:22         ` Andy Shevchenko
2021-04-01 18:32           ` Mika Westerberg
2021-07-12 12:13             ` Andy Shevchenko
2021-03-08 12:20 ` [PATCH v1 4/7] mfd: lpc_ich: Factor out lpc_ich_enable_spi_write() Andy Shevchenko
2021-03-10 10:29   ` Lee Jones
2021-03-08 12:20 ` [PATCH v1 5/7] mfd: lpc_ich: Switch to generic pci_p2sb_bar() Andy Shevchenko
2021-03-10 10:35   ` Lee Jones
2021-03-10 12:05     ` Andy Shevchenko
2021-03-10 12:57       ` Lee Jones
2021-03-08 12:20 ` [PATCH v1 6/7] mfd: lpc_ich: Add support for pinctrl in non-ACPI system Andy Shevchenko
2021-03-10 10:27   ` Lee Jones
2021-04-12 16:01   ` Henning Schild
2021-04-12 16:40     ` Henning Schild
2021-04-12 16:59       ` Andy Shevchenko
2021-04-12 17:16         ` Henning Schild
2021-04-12 17:34           ` Andy Shevchenko
2021-04-13  6:47             ` Henning Schild
2021-04-12 16:51     ` Andy Shevchenko
2021-04-12 17:27       ` Henning Schild
2021-04-12 17:41         ` Andy Shevchenko
2021-03-08 12:20 ` [PATCH v1 7/7] i2c: i801: convert to use common P2SB accessor Andy Shevchenko
2021-03-10 14:51   ` Jean Delvare
2021-12-21 15:08     ` Andy Shevchenko
2021-03-13  9:25 ` [rfc, PATCH v1 0/7] PCI: introduce p2sb helper Henning Schild
2021-06-10  9:02 ` Henning Schild
2021-06-10 10:14   ` Andy Shevchenko
2021-06-10 13:48     ` Henning Schild
2021-06-10 14:04       ` Andy Shevchenko
2021-11-26 15:43 ` Andy Shevchenko

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