LKML Archive on lore.kernel.org
help / color / mirror / Atom feed
From: Samuel Ortiz <sameo@linux.intel.com>
To: Grant Likely <grant.likely@secretlab.ca>
Cc: Andres Salomon <dilinger@queued.net>,
	linux-kernel@vger.kernel.org,
	Mark Brown <broonie@opensource.wolfsonmicro.com>,
	khali@linux-fr.org, ben-linux@fluff.org,
	Peter Korsgaard <jacmet@sunsite.dk>,
	Mauro Carvalho Chehab <mchehab@infradead.org>,
	David Brownell <dbrownell@users.sourceforge.net>,
	linux-i2c@vger.kernel.org, linux-media@vger.kernel.org,
	netdev@vger.kernel.org, spi-devel-general@lists.sourceforge.net,
	Mocean Laboratories <info@mocean-labs.com>,
	Greg Kroah-Hartman <gregkh@suse.de>
Subject: Re: [PATCH 07/19] timberdale: mfd_cell is now implicitly available to drivers
Date: Mon, 4 Apr 2011 12:03:15 +0200	[thread overview]
Message-ID: <20110404100314.GC2751@sortiz-mobl> (raw)
In-Reply-To: <BANLkTi=bq=OGzXFp7qiBr7x_BnGOWf=DRQ@mail.gmail.com>

On Fri, Apr 01, 2011 at 05:58:44PM -0600, Grant Likely wrote:
> On Fri, Apr 1, 2011 at 5:52 PM, Samuel Ortiz <sameo@linux.intel.com> wrote:
> > On Fri, Apr 01, 2011 at 11:56:35AM -0600, Grant Likely wrote:
> >> On Fri, Apr 1, 2011 at 11:47 AM, Andres Salomon <dilinger@queued.net> wrote:
> >> > On Fri, 1 Apr 2011 13:20:31 +0200
> >> > Samuel Ortiz <sameo@linux.intel.com> wrote:
> >> >
> >> >> Hi Grant,
> >> >>
> >> >> On Thu, Mar 31, 2011 at 05:05:22PM -0600, Grant Likely wrote:
> >> > [...]
> >> >> > Gah.  Not all devices instantiated via mfd will be an mfd device,
> >> >> > which means that the driver may very well expect an *entirely
> >> >> > different* platform_device pointer; which further means a very high
> >> >> > potential of incorrectly dereferenced structures (as evidenced by a
> >> >> > patch series that is not bisectable).  For instance, the xilinx ip
> >> >> > cores are used by more than just mfd.
> >> >> I agree. Since the vast majority of the MFD subdevices are MFD
> >> >> specific IPs, I overlooked that part. The impacted drivers are the
> >> >> timberdale and the DaVinci voice codec ones.
> >>
> >> Another option is you could do this for MFD devices:
> >>
> >> struct mfd_device {
> >>         struct platform_devce pdev;
> >>         struct mfd_cell *cell;
> >> };
> >>
> >> However, that requires that drivers using the mfd_cell will *never*
> >> get instantiated outside of the mfd infrastructure, and there is no
> >> way to protect against this so it is probably a bad idea.
> >>
> >> Or, mfd_cell could be added to platform_device directly which would
> >> *by far* be the safest option at the cost of every platform_device
> >> having a mostly unused mfd_cell pointer.  Not a significant cost in my
> >> opinion.
> > I thought about this one, but I had the impression people would want to kill
> > me for adding an MFD specific pointer to platform_device. I guess it's worth
> > giving it a try since it would be a simple and safe solution.
> > I'll look at it later this weekend.
> >
> > Thanks for the input.
> 
> [cc'ing gregkh because we're talking about modifying struct platform_device]
> 
> I'll back you up on this one.  It is a far better solution than the
> alternatives.  At least with mfd, it covers a large set of devices.  I
> think there is a strong argument for doing this.  Or alternatively,
> the particular interesting fields from mfd_cell could be added to
> platform_device.  What information do child devices need access to?
In some cases, they need the whole cell to clone it. So I'm up for adding an
mfd_cell pointer to the platform_device structure.
Below is a tentative patch. This is a first step and would fix all
regressions. I tried to keep the MFD dependencies as small as possible, which
is why I placed the pdev->mfd_cell building code in mfd-core.c
The second step would be to get rid of mfd_get_data() and have all subdrivers
going back to the regular platform_data way. They would no longer be dependant
on the MFD code except for those who really need it. In that case they could
just call mfd_get_cell() and get full access to their MFD cell.

--- 
 drivers/mfd/mfd-core.c          |   27 ++++++++++++++++++++++-----
 include/linux/mfd/core.h        |    7 +++++--
 include/linux/platform_device.h |    5 +++++
 3 files changed, 32 insertions(+), 7 deletions(-)

diff --git a/drivers/mfd/mfd-core.c b/drivers/mfd/mfd-core.c
index d01574d..c0fc1c0 100644
--- a/drivers/mfd/mfd-core.c
+++ b/drivers/mfd/mfd-core.c
@@ -18,6 +18,21 @@
 #include <linux/pm_runtime.h>
 #include <linux/slab.h>
 
+static int mfd_platform_add_cell(struct platform_device *pdev, const struct mfd_cell *cell)
+{
+	struct mfd_cell *c;
+
+	if (cell == NULL)
+		return 0;
+
+	c = kmemdup(cell, sizeof(struct mfd_cell), GFP_KERNEL);
+	if (c == NULL)
+		return -ENOMEM;
+
+	pdev->mfd_cell = c;
+	return 0;
+}
+
 int mfd_cell_enable(struct platform_device *pdev)
 {
 	const struct mfd_cell *cell = mfd_get_cell(pdev);
@@ -75,7 +90,7 @@ static int mfd_add_device(struct device *parent, int id,
 
 	pdev->dev.parent = parent;
 
-	ret = platform_device_add_data(pdev, cell, sizeof(*cell));
+	ret = mfd_platform_add_cell(pdev, cell);
 	if (ret)
 		goto fail_res;
 
@@ -104,17 +119,17 @@ static int mfd_add_device(struct device *parent, int id,
 		if (!cell->ignore_resource_conflicts) {
 			ret = acpi_check_resource_conflict(res);
 			if (ret)
-				goto fail_res;
+				goto fail_cell;
 		}
 	}
 
 	ret = platform_device_add_resources(pdev, res, cell->num_resources);
 	if (ret)
-		goto fail_res;
+		goto fail_cell;
 
 	ret = platform_device_add(pdev);
 	if (ret)
-		goto fail_res;
+		goto fail_cell;
 
 	if (cell->pm_runtime_no_callbacks)
 		pm_runtime_no_callbacks(&pdev->dev);
@@ -123,7 +138,8 @@ static int mfd_add_device(struct device *parent, int id,
 
 	return 0;
 
-/*	platform_device_del(pdev); */
+fail_cell:
+	kfree(pdev->mfd_cell);
 fail_res:
 	kfree(res);
 fail_device:
@@ -171,6 +187,7 @@ static int mfd_remove_devices_fn(struct device *dev, void *c)
 	if (!*usage_count || (cell->usage_count < *usage_count))
 		*usage_count = cell->usage_count;
 
+	kfree(pdev->mfd_cell);
 	platform_device_unregister(pdev);
 	return 0;
 }
diff --git a/include/linux/mfd/core.h b/include/linux/mfd/core.h
index ad1b19a..0e4d3a6 100644
--- a/include/linux/mfd/core.h
+++ b/include/linux/mfd/core.h
@@ -86,7 +86,7 @@ extern int mfd_clone_cell(const char *cell, const char **clones,
  */
 static inline const struct mfd_cell *mfd_get_cell(struct platform_device *pdev)
 {
-	return pdev->dev.platform_data;
+	return pdev->mfd_cell;
 }
 
 /*
@@ -95,7 +95,10 @@ static inline const struct mfd_cell *mfd_get_cell(struct platform_device *pdev)
  */
 static inline void *mfd_get_data(struct platform_device *pdev)
 {
-	return mfd_get_cell(pdev)->mfd_data;
+	if (pdev->mfd_cell != NULL)
+		return mfd_get_cell(pdev)->mfd_data;
+	else
+		return pdev->dev.platform_data;
 }
 
 extern int mfd_add_devices(struct device *parent, int id,
diff --git a/include/linux/platform_device.h b/include/linux/platform_device.h
index d96db98..734d254 100644
--- a/include/linux/platform_device.h
+++ b/include/linux/platform_device.h
@@ -14,6 +14,8 @@
 #include <linux/device.h>
 #include <linux/mod_devicetable.h>
 
+struct mfd_cell;
+
 struct platform_device {
 	const char	* name;
 	int		id;
@@ -23,6 +25,9 @@ struct platform_device {
 
 	const struct platform_device_id	*id_entry;
 
+	/* MFD cell pointer */
+	struct mfd_cell	*mfd_cell;
+
 	/* arch specific additions */
 	struct pdev_archdata	archdata;
 };

-- 
Intel Open Source Technology Centre
http://oss.intel.com/

  parent reply	other threads:[~2011-04-04 10:03 UTC|newest]

Thread overview: 65+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2011-02-03  3:54 [RFC] [PATCH 0/19] mfd sharing support Andres Salomon
2011-02-03  3:55 ` [PATCH 01/19] mfd-core: unconditionally add mfd_cell to every platform_device Andres Salomon
2011-02-03  3:58 ` [PATCH 02/19] jz4740: mfd_cell is now implicitly available to drivers Andres Salomon
2011-02-03  8:09   ` Jean Delvare
2011-02-03  4:01 ` [PATCH 03/19] ab3550: " Andres Salomon
2011-02-04  8:20   ` Mattias Wallin
2011-02-03  4:03 ` [PATCH 04/19] ab3100: " Andres Salomon
2011-02-03 12:52   ` Linus Walleij
2011-02-03  4:04 ` [PATCH 05/19] asic3: " Andres Salomon
2011-02-03  4:05 ` [PATCH 06/19] htc-pasic3: " Andres Salomon
2011-02-03  4:08 ` [PATCH 07/19] timberdale: " Andres Salomon
2011-03-31 23:05   ` Grant Likely
2011-04-01 11:20     ` Samuel Ortiz
2011-04-01 17:47       ` Andres Salomon
2011-04-01 17:56         ` Grant Likely
2011-04-01 18:00           ` Grant Likely
2011-04-01 23:52           ` Samuel Ortiz
2011-04-01 23:58             ` Grant Likely
2011-04-02  0:10               ` Andres Salomon
2011-04-04 10:03               ` Samuel Ortiz [this message]
2011-04-05  3:04                 ` Grant Likely
2011-04-06 15:23                   ` Samuel Ortiz
2011-04-06 15:58                     ` Greg KH
2011-04-06 17:05                       ` Samuel Ortiz
2011-04-06 17:16                         ` Ben Hutchings
2011-04-06 17:51                           ` Samuel Ortiz
2011-04-06 18:07                             ` Ben Hutchings
2011-04-06 17:56                         ` Greg KH
2011-04-06 18:25                           ` Andres Salomon
2011-04-06 18:38                             ` Greg KH
2011-04-07  8:04                               ` Grant Likely
2011-04-06 18:47                           ` Samuel Ortiz
2011-04-06 18:59                             ` Felipe Balbi
2011-04-06 22:09                               ` Greg KH
2011-04-07  8:09                                 ` Felipe Balbi
2011-04-07 13:40                               ` Samuel Ortiz
2011-04-07 14:35                                 ` Grant Likely
2011-04-07 15:03                                   ` Samuel Ortiz
2011-04-07 18:06                                     ` Grant Likely
2011-04-07 16:24                   ` Grant Likely
2011-04-01 18:26         ` Samuel Ortiz
2011-02-03  4:09 ` [PATCH 08/19] t7166xb: " Andres Salomon
2011-02-03  4:11 ` [PATCH 09/19] wl1273: " Andres Salomon
2011-02-03  4:12 ` [PATCH 10/19] sh_mobile_sdhi: " Andres Salomon
2011-02-03  4:13 ` [PATCH 11/19] tc6393xb: " Andres Salomon
2011-02-03  4:15 ` [PATCH 12/19] twl4030: " Andres Salomon
2011-02-03  6:05   ` Dmitry Torokhov
2011-02-03  6:39     ` Andres Salomon
2011-02-03  6:53       ` Dmitry Torokhov
2011-02-03  7:03         ` Andres Salomon
2011-02-03  9:31           ` Mark Brown
2011-02-05  2:39             ` Andres Salomon
2011-02-05  3:25               ` Andres Salomon
2011-02-03 12:23           ` Peter Ujfalusi
2011-02-04 10:41           ` Uwe Kleine-König
2011-02-03  4:16 ` [PATCH 13/19] tc6387xb: " Andres Salomon
2011-02-03  4:17 ` [PATCH 14/19] janz: " Andres Salomon
2011-02-03  4:20 ` [PATCH 15/19] mc13xxx: " Andres Salomon
2011-02-04  9:34   ` Uwe Kleine-König
2011-02-04 10:13     ` Uwe Kleine-König
2011-02-04 10:16     ` Andres Salomon
2011-02-03  4:21 ` [PATCH 16/19] mfd-core: drop platform_data/data_size from core mfd_cell struct Andres Salomon
2011-02-03  4:22 ` [PATCH 17/19] mfd-core: add refcounting support to mfd_cells Andres Salomon
2011-02-03  4:23 ` [PATCH 18/19] mfd-core: add platform_device sharing support for mfd Andres Salomon
2011-02-03  4:26 ` [PATCH 19/19] cs5535-mfd: add sharing for acpi/pms cells Andres Salomon

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20110404100314.GC2751@sortiz-mobl \
    --to=sameo@linux.intel.com \
    --cc=ben-linux@fluff.org \
    --cc=broonie@opensource.wolfsonmicro.com \
    --cc=dbrownell@users.sourceforge.net \
    --cc=dilinger@queued.net \
    --cc=grant.likely@secretlab.ca \
    --cc=gregkh@suse.de \
    --cc=info@mocean-labs.com \
    --cc=jacmet@sunsite.dk \
    --cc=khali@linux-fr.org \
    --cc=linux-i2c@vger.kernel.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux-media@vger.kernel.org \
    --cc=mchehab@infradead.org \
    --cc=netdev@vger.kernel.org \
    --cc=spi-devel-general@lists.sourceforge.net \
    --subject='Re: [PATCH 07/19] timberdale: mfd_cell is now implicitly available to drivers' \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).